MAX8834 [MAXIM]
Adaptive Step-Up Converters with 1.5A Flash Driver;
| 型号： | MAX8834 |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Adaptive Step-Up Converters with 1.5A Flash Driver |
| 文件： | 总44页 (文件大小：984K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
EVALUATION KIT AVAILABLE
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
General Description
Features
o 2.5V to 5.5V Operation Range
o Step-Up DC-DC Converter
The MAX8834Y/MAX8834Z flash drivers integrate a
1.5A PWM DC-DC step-up converter and three pro-
grammable low-side, low-dropout LED current regula-
tors. The step-up converter features an internal
switching MOSFET and synchronous rectifier to
improve efficiency and minimize external component
1.5A Guaranteed Output Current
2
Adaptive or I C Programmable Output Voltage
2MHz and 4MHz Switching Frequency Options
o Two Flash/Movie LED Current Regulators
2
count. An I C interface provides flexible control of step-
2
I C Programmable Flash and Movie Current
up converter output voltage setting, movie/flash mode
selection, flash timer duration settings, and current reg-
ulator settings. The MAX8834Y/MAX8834Z operate
down to 2.5V, making them future proof for new battery
technologies.
Low-Dropout Voltage (110mV max) at 500mA
o LED Indicator Current Regulator
2
I C Programmable Output Current
Ramp and Blink Timers for Indicator Mode
Low-Dropout Voltage (130mV max) at 16mA
The MAX8834Y/MAX8834Z consist of two current regula-
tors for the flash/movie mode. Each current regulator can
sink 750mA in flash mode and 125mA in movie mode.
The MAX8834Y/MAX8834Z also integrate a 16mA low-
current regulator that can be used to indicate camera
status. The indicator current regulator includes program-
mable ramp and blink timer settings. A programmable
input current limit, invoked using the GSMB control,
reduces the total current drawn from the battery during
PA transmit events. This ensures the flash current is set
to the maximum possible for any given operating condi-
tion. Additionally, the MAX8834Y/MAX8834Z include a
MAXFLASH function that adaptively reduces flash cur-
rent during low battery conditions to help prevent system
undervoltage lockup.
2
o I C Programmable Safety and Watchdog Timers
o GSM Blank Logic Input
o MAXFLASH System Lockup Protection
o Remote Temperature Sensor Input
o Open/Short LED Detection
o Thermal Shutdown Protection
o < 1µA Shutdown Current
o 20-Bump, 0.5mm Pitch, 2.5mm x 2.0mm WLP
Applications
Cell Phones and Smart Phones
PDAs, Digital Cameras, and Camcorders
Other features include an optional NTC input for finger-
burn protection and open/short LED detection. The
MAX8834Y switches at 2MHz, providing best overall
efficiency. The MAX8834Z switches at 4MHz, providing
smallest overall solution size. The MAX8834Y/
MAX8834Z are available in a 20-bump, 0.5mm pitch
WLP package (2.5mm x 2.0mm).
Typical Operating Circuit
1µH OR 2.2µH
PROGRAMMABLE
OUTPUT
INPUT
2.5V TO 5.5V
3.7V TO 5.2V
LX
IN
OUT
10µF
10µF
Ordering Information
AGND
PGND
SWITCHING
PIN-PACKAGE FREQUENCY
(MHz)
TEMP
PART
COMP
FLED1
MAX8834Y
MAX8834Z
RANGE
1.5A TOTAL
FLASH
-40°C to 20 WLP
+85°C (2.5mm x 2.0mm)
FLED2
MAX8834YEWP+T
MAX8834ZEWP+T
2
4
PA_TXON
GSMB
LED_EN
SCL
-40°C to 20 WLP
+85°C (2.5mm x 2.0mm)
INDLED
16mA INDICATOR
FLASH ON
FGND
NTC
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
2
I C
SDA
V
LOGIC
FINGER-BURN
PROTECTION
Pin Configuration appears at end of data sheet.
V
DD
0.1µF
Visit www.maximintegrated.com/products/patents for
product patent marking information.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-4421; Rev 2; 2/10
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
ABSOLUTE MAXIMUM RATINGS
IN, OUT, NTC to AGND.........................................-0.3V to +6.0V
Continuous Power Dissipation (T = +70°C)
A
V
to AGND.........................................................-0.3V to +4.0V
(derate 17.5mW/°C above +70°C).............................1410mW
DD
SCL, SDA, LED_EN, GSMB to AGND ........-0.3V to (V
FLED1, FLED2, INDLED to FGND............-0.3V to (V
COMP to AGND...........................................-0.3V to (V + 0.3V)
PGND, FGND to AGND.........................................-0.3V to +0.3V
+ 0.3V)
+ 0.3V)
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Bump Temperature* (soldering) ......................................+260°C
DD
OUT
IN
I
LX
Current (rms) ......................................................................3A
*This device is constructed using a unique set of packaging techniques that impose a limit on the thermal profile the device can be exposed to during board
level solder attach and rework. This limit permits only the use of the solder profiles recommended in the industry-standard specification, JEDEC 020A, para-
graph 7.6, Table 3 for IR/VPR and Convection reflow. Preheating is required. Hand or wave soldering is not allowed.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V = 3.6V, V
= V
= V
= 0V, V
= 1.8V, T = -40°C to +85°C, unless otherwise noted. Typical values are at
DD A
IN
AGND
PGND
FGND
T
A
= +25°C.) (Note 1)
PARAMETER
IN Operating Voltage
CONDITIONS
MIN
2.5
TYP
MAX
5.5
UNITS
V
V
V
DD
Operating Range
1.62
3.6
V
Undervoltage Lockout
DD
V
V
falling
falling
1.25
2.15
1.4
1.55
2.45
V
DD
(UVLO) Threshold
V
DD
UVLO Hysteresis
50
2.3
50
mV
V
IN UVLO Threshold
IN UVLO Hysteresis
IN
mV
2
IN Standby Supply Current
V
V
= V
= V
= V , V = 5.5V, I C ready
DD IN
1
7
µA
SCL
SCL
SDA
SDA
V
DD
Standby Supply Current
2
2
= V = 3.6V, I C ready
4
µA
DD
(All Outputs Off, I C Enabled)
LOGIC INTERFACE
LED_EN, GSMB
SCL, SDA
1.4
Logic Input-High Voltage
V
V
= 1.62V to 3.6V
= 1.62V to 3.6V
V
V
DD
0.7 x
V
DD
LED_EN, GSMB
SCL, SDA
0.4
Logic Input-Low Voltage
DD
0.3 x
V
DD
LED_EN Minimum High Time
(LED_EN is Internally Sampled
by a 1MHz Clock)
1
µs
From LED_EN going high to rising edge on current
regulator
LED_EN Propagation Delay
3
µs
kꢀ
µA
LED_EN and GSMB Pulldown
Resistor
400
-1
800
1600
+1
T
T
= +25°C
= +85°C
0.01
0.1
A
Logic Input Current (SCL, SDA)
V = 0V or V = 3.6V
IL IH
A
2
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
ELECTRICAL CHARACTERISTICS (continued)
(V = 3.6V, V
IN
= V
= V
= 0V, V
= 1.8V, T = -40°C to +85°C, unless otherwise noted. Typical values are at
DD A
AGND
PGND
FGND
T
A
= +25°C.) (Note 1)
PARAMETER
CONDITIONS
MIN
TYP
0.01
0.1
MAX
UNITS
T
T
= +25°C
= +85°C
-1
+1
IN and V in UVLO,
A
DD
Shutdown Leakage Current
µA
V
= V
= 0V
GSMB
LED_EN
A
2
I C INTERFACE
SDA Output Low Voltage
I
= 3mA
0.03
0.4
V
SDA
BUF
2
I C Clock Frequency
400
kHz
Bus-Free Time Between STOP
and START
t
t
1.3
0.6
µs
µs
Hold Time Repeated START
Condition
0.1
HD_STA
SCL Low Period
SCL High Period
t
t
1.3
0.6
0.2
0.2
µs
µs
LOW
HIGH
Setup Time Repeated START
Condition
t
0.6
0.1
µs
SU_STA
SDA Hold Time
SDA Setup Time
t
t
t
0
-0.01
50
µs
ns
µs
HD_DAT
SU_DAT
SU_STO
100
0.6
Setup Time for STOP Condition
STEP-UP DC-DC CONVERTER
OUT Voltage Range
0.1
100mV steps
No load, V
3.7
-2.75
5.2
5.2
+2.75
5.5
V
%
V
OUT Voltage Accuracy
= 5V
0.5
OUT
OUT Overvoltage Protection
When running in adaptive mode
= I = 492.24mA setting, I = 16mA
INDLED
5.35
Adaptive Output Voltage
Regulation Threshold
I
150
mV
FLED1
FLED2
PGOOD Window Comparator
Line Regulation
V
V
= 5V, in programmable mode
-15
-12.5
0.1
-10
%
%/V
%/A
A
OUT
= 2.5V to 4.2V
IN
Load Regulation
I
= 0mA to 1500mA
0.5
OUT
nFET Current Limit
3.6
LX nFET On-Resistance
LX pFET On-Resistance
LX to PGND, I = 200mA
0.055
0.12
0.1
0.130
0.200
1
ꢀ
LX
LX to OUT, I = 200mA
ꢀ
LX
T
T
= +25°C
A
LX Leakage
V
LX
= 5.5V
µA
= +85°C
0.1
A
Input Current Limit Range During
GSMB Trigger
50
800
mA
Input Current Limit Step Size
During GSMB Trigger
50
mA
%
Input Current Limit Accuracy
I
= 100mA, in dropout mode
-15
1.8
1.6
3.6
3.2
+15
2.2
2.4
4.4
4.8
ILIM
T
A
T
A
T
A
T
A
= +25°C
2
4
MAX8834Y
MAX8834Z
= -40°C to +85°C
= +25°C
Operating Frequency, No Load
MHz
= -40°C to +85°C
Maxim Integrated
3
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
ELECTRICAL CHARACTERISTICS (continued)
(V = 3.6V, V
IN
= V
= V
= 0V, V
= 1.8V, T = -40°C to +85°C, unless otherwise noted. Typical values are at
DD A
AGND
PGND
FGND
T
A
= +25°C.) (Note 1)
PARAMETER
CONDITIONS
MIN
TYP
75
MAX
UNITS
%
Maximum Duty Cycle
Minimum Duty Cycle
V
V
V
= 4.5V
= 4.5V
69
OUT
7.5
55
%
OUT
COMP Transconductance
COMP Discharge Resistance
OUT Discharge Resistance
= 1.5V
µS
COMP
During shutdown or UVLO, from COMP to AGND
During shutdown or UVLO, from OUT to LX
120
10
ꢀ
kꢀ
FLED1/FLED2 CURRENT REGULATOR
Step-up off, FLED1/FLED2 on, supply current for each
current source
IN Supply Current
0.6
mA
Flash
750
125
Maximum Current Setting
mA
%
Movie
23.44mA setting
T
A
T
A
T
A
T
A
= +25°C
-5
-2.5
-4
+20
+2.5
+4
= +25°C
0.5
Current Accuracy
492.24mA setting
%
= -40°C to +85°C
= -40°C to +85°C
750mA setting
-10
+5
%
492.24mA setting
93.75mA setting
110
100
+1
Current Regulator Dropout
(Note 2)
mV
50
0.01
0.1
T
T
= +25°C
= +85°C
-1
FLED1/FLED2 Leakage in
Shutdown
A
V
= V
= 5.5V
µA
FLED1
FLED2
A
INDLED CURRENT REGULATOR
IN Supply Current
Step-up converter off, INDLED on
0.6
16
mA
mA
%
Maximum Current Setting
0.5mA setting
T
A
T
A
T
A
= +25°C
-10
-3
+10
+3
Current Accuracy
= +25°C
0.5
%
16mA setting
= -40°C to +85°C
-5
+5
%
Current Regulator Dropout
16mA setting (Note 2)
55
0.01
0.1
130
+1
mV
T
T
= +25°C
= +85°C
-1
A
INDLED Leakage in Shutdown
V
= 5.5V
µA
INDLED
A
PROTECTION CIRCUITS
NTC BIAS Current
19.4
388
20
20.6
412
µA
NTC Overtemperature Detection
Threshold
V
V
falling, 100mV hysteresis, NTC_CNTL[2:0] = 100
falling
400
100
mV
NTC
NTC Short Detection Threshold
Flash Duration Timer Range
mV
ms
NTC
In 50ms steps (Note 3)
50
800
440
480
T
A
T
A
= +25°C
360
320
400
Flash Duration Timer Accuracy
(400ms Setting)
ms
ms
ms
s
= -40°C to +85°C
Minimum Flash Duration
FLASH_EN[2:0] = 1XX
2
Flash Safety Timer Reset Inhibit From falling edge of LED_EN until flash safety timer is
Period
30
reset
Watchdog Timer Range
In 4s steps
4
16
4
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
ELECTRICAL CHARACTERISTICS (continued)
(V = 3.6V, V
IN
= V
= V
= 0V, V
= 1.8V, T = -40°C to +85°C, unless otherwise noted. Typical values are at
DD A
AGND
PGND
FGND
T
A
= +25°C.) (Note 1)
PARAMETER
CONDITIONS
MIN
3.6
3.2
TYP
MAX
4.4
UNITS
T
T
= +25°C
4
Watchdog Timer Accuracy
(4s setting)
A
s
mV
V
= -40°C to +85°C
4.8
A
Open LED Detection Threshold
FLED1, FLED2, INDLED enabled
100
V
-
OUT
1V
Shorted LED Detection Threshold FLED1, FLED2, INDLED enabled
From LED open or short detected until LED current
regulator is disabled
Open and Short Debounce Timer
30
20
ms
Thermal-Shutdown Hysteresis
Thermal Shutdown
MAXFLASH
°C
°C
+160
Low-Battery Detect Threshold
Range
33mV steps
2.5
3.4
V
Low-Battery Voltage Threshold
Accuracy
2.5
%
Low-Battery Voltage Hysteresis
Programmable Range
100
200
mV
mV
µs
Low-Battery Voltage Hysteresis
Step Size
100
LB_TMR[1:0] = 00
LB_TMR[1:0] = 01
200
400
250
500
300
600
Low-Battery Reset Time
Note 1: All devices are 100% production tested at T = +25°C. Limits over the operating temperature range are guaranteed by
A
design.
Note 2: LED current regulator dropout voltage is defined as the voltage when current drops 10% from the current level measured at
0.6V.
Note 3: Flash duration is from rising edge of LED_EN until I
= 0A (safety time in one-shot mode).
FLED
Note 4: The adaptive output voltage regulation threshold is individually set on each device to 75mV above the dropout voltage of
the LED current regulators. This ensures minimum power dissipation on the IC during a flash event. The dropout voltage
chosen is the highest measured dropout voltage of FLED1, FLED2, and INDLED.
Maxim Integrated
5
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Typical Operating Characteristics
(Circuit of Figure 1, V = 3.6V, V
= 3.8V, V
= 3.0V, T = +25°C, unless otherwise noted.)
IN
OUT
DD
A
STEP-UP CONVERTER EFFICIENCY
vs. INPUT VOLTAGE (MAX8834Y)
STEP-UP CONVERTER EFFICIENCY
vs. INPUT VOLTAGE (MAX8834Z)
STEP-UP CONVERTER EFFICIENCY
vs. OUTPUT CURRENT (MAX8834Y)
100
90
80
70
60
50
40
30
20
10
0
100
100
80
60
40
20
0
V
= 3.6V
IN
90
80
70
60
50
40
30
20
10
0
V
= 3.8V
OUT
I
= 16mA
V
OUT
= 3.8V
= 750mA
OUT
OUT
V
OUT
= 5V
= 750mA
V
= 3.2V
= 2.5V
OUT
IN
I
I
V
OUT
= 3.8V
= 750mA
V
OUT
IN
V
OUT
= 5V
= 16mA
OUT
I
I
V
OUT
= 5V
= 250mA
OUT
V
OUT
= 5V
= 250mA
OUT
V
OUT
= 5V
= 16mA
OUT
I
V
OUT
= 5V
= 750mA
OUT
I
V
= 3.8V
= 16mA
I
OUT
I
V
= 3.8V
V
= 3.8V
= 250mA
OUT
I
OUT
OUT
OUT
I
= 250mA
I
OUT
FOR V > V , V
INCREASES ABOVE THE
FOR V > V , V
INCREASES ABOVE THE
IN
OUT OUT
IN
OUT OUT
PROGRAMMED VALUE DUE TO THE MINIMUM
DUTY CYCLE CONSTRAINT.
PROGRAMMED VALUE DUE TO THE MINIMUM
DUTY CYCLE CONSTRAINT.
2.5
3.0
3.5
4.0
4.5
5.0
2.5
3.0
3.5
4.0
4.5
5.0
1
10
100
1000
10,000
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
STEP-UP CONVERTER EFFICIENCY
vs. OUTPUT CURRENT (MAX8834Z)
STEP-UP CONVERTER SUPPLY CURRENT
vs. TEMPERATURE
STEP-UP CONVERTER SUPPLY CURRENT
vs. SUPPLY VOLTAGE
100
80
60
40
20
0
20
15
10
5
15
12
9
V
= 3.6V
IN
V
= 3.8V
V
OUT
= 5V
OUT
V
= 3.2V
= 2.5V
IN
MAX8834Z
MAX8834Y
V
MAX8834Z
IN
MAX8834Y
6
3
0
0
1
10
100
1000
10,000
-40
-15
10
35
60
85
2.5
3.0
3.5
4.0
4.5
5.0
OUTPUT CURRENT (mA)
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
LED CURRENT ACCURACY
vs. INPUT VOLTAGE
LED CURRENT ACCURACY
vs. TEMPERATURE
10
10
5
8
6
I
= 125mA
FLED2
I
= 125mA
FLED1
I
= 125mA
4
FLED1
I
= 125mA
I
= 492.19mA
FLED2
FLED1
I
= 492.19mA
FLED1
2
0
0
I
= 492.19mA
FLED2
I
= 16mA
I
= 16mA
-2
-4
-6
-8
-10
INDLED
INDLED
I
= 750mA
= 750mA
FLED1
I
= 750mA
FLED1
-5
-10
I
= 750mA
FLED2
I
= 492.19mA
FLED2
I
FLED2
V
OUT
= 5V
5.0
V
OUT
= 5V
2.5
3.0
3.5
4.0
4.5
5.5
-40
-15
10
35
60
85
INPUT VOLTAGE (V)
TEMPERATURE (°C)
6
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Typical Operating Characteristics (continued)
(Circuit of Figure 1, V = 3.6V, V
= 3.8V, V
= 3.0V, T = +25°C, unless otherwise noted.)
DD A
IN
OUT
OUTPUT VOLTAGE ACCURACY
vs. TEMPERATURE
INTERNAL OSCILLATOR FREQUENCY
vs. SUPPLY VOLTAGE
0.6
0.4
0.2
0
5
4
3
2
1
0
V
= 5V
OUT
MAX8834Z, NO LOAD
MAX8834Z
MAX8834Y
MAX8834Y, NO LOAD
MAX8834Y, I
= 250mA
OUT
-0.2
-0.4
-0.6
MAX8834Z, I
-15
= 250mA
OUT
-40
10
35
60
85
2.5
3.0
3.5
4.0
4.5
5.0
5.5
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
STARTUP WAVEFORM
STARTUP WAVEFORM
(MAX8834Y, V
= 5V)
(MAX8834Y, ADAPTIVE MODE)
OUT
MAX8834Y/Z toc11
MAX8834Y/Z toc12
2V/div
2V/div
2V/div
5V
V
V
OUT
OUT
2V/div
V
V
LX
LX
LX
LX
ADAPTIVE MODE
= 31.25mA
V
LED1
= 5V
= 31.25mA
OUT
I
LED1
I
I
I
500mA/div
1V/div
500mA/div
1V/div
V
COMP
V
COMP
1ms/div
1ms/div
STARTUP WAVEFORM
STARTUP WAVEFORM
(MAX8834Z, V
= 5V)
(MAX8834Z, ADAPTIVE MODE)
OUT
MAX8834Y/Z toc13
MAX8834Y/Z toc14
2V/div
2V/div
2V/div
2V/div
5V
V
OUT
V
OUT
V
LX
LX
V
LX
LX
V
LED1
= 5V
= 31.25mA
ADAPTIVE MODE
= 31.25mA
OUT
I
I
LED1
I
I
500mA/div
1V/div
500mA/div
1V/div
V
COMP
V
COMP
1ms/div
1ms/div
Maxim Integrated
7
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Typical Operating Characteristics (continued)
(Circuit of Figure 1, V = 3.6V, V
= 3.8V, V
= 3.0V, T = +25°C, unless otherwise noted.)
DD A
IN
OUT
SHUTDOWN WAVEFORM
(MAX8834Y, V = 5V)
SHUTDOWN WAVEFORM
(MAX8834Y, ADAPTIVE MODE)
OUT
MAX8834Y/Z toc15
MAX8834Y/Z toc16
5V
V
V
2V/div
2V/div
OUT
OUT
2V/div
2V/div
V
V
LX
LX
LX
ADAPTIVE MODE
= 31.25mA
V
LED1
= 5V
= 31.25mA
OUT
I
I
LED1
I
500mA/div
1V/div
500mA/div
1V/div
I
LX
V
V
COMP
COMP
400µs/div
400µs/div
SHUTDOWN WAVEFORM
(MAX8834Z, V = 5V)
SHUTDOWN WAVEFORM
(MAX8834Z, ADAPTIVE MODE)
OUT
MAX8834Y/Z toc17
MAX8834Y/Z toc18
2V/div
2V/div
5V
2V/div
2V/div
V
V
OUT
OUT
V
V
LX
LX
V
LED1
= 5V
= 31.25mA
OUT
ADAPTIVE MODE
= 31.25mA
I
LX
I
I
LED1
500mA/div
1V/div
500mA/div
1V/div
I
LX
V
COMP
V
COMP
400µs/div
400µs/div
LIGHT-LOAD SWITCHING WAVEFORMS
LIGHT-LOAD SWITCHING WAVEFORMS
(MAX8834Y)
(MAX8834Z)
MAX8834Y/Z toc20
MAX8834Y/Z toc19
2V/div
0V
2V/div
0V
V
V
LX
LX
0mA
0mA
I
LX
I
LX
200mA/div
200mA/div
V
I
= 5V
= 16mA
OUT
OUT
V
I
= 5V
= 16mA
OUT
OUT
V
V
OUT
AC RIPPLE
OUT
20mV/div
20mV/div
AC RIPPLE
400ns/div
400ns/div
8
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Typical Operating Characteristics (continued)
(Circuit of Figure 1, V = 3.6V, V
= 3.8V, V
= 3.0V, T = +25°C, unless otherwise noted.)
DD A
IN
OUT
HEAVY-LOAD SWITCHING WAVEFORMS
HEAVY-LOAD SWITCHING WAVEFORMS
(MAX8834Y)
(MAX8834Z)
MAX8834Y/Z toc21
MAX8834Y/Z toc22
2V/div
0V
2V/div
0V
V
V
LX
LX
LX
500mA/div
1.5A
1.5A
I
I
LX
500mA/div
V
I
= 5V
= 1A
V
I
= 5V
= 1A
OUT
OUT
OUT
OUT
V
V
OUT
AC RIPPLE
OUT
50mV/div
50mV/div
AC RIPPLE
400ns/div
400ns/div
GSMB WAVEFORM
MAXFLASH FUNCTION
MAX8834Y/Z toc23
MAX8834Y/Z toc24
V
DROPS
IN
3.6V
3.6V
BELOW THE
THRESHOLD
VOLTAGE
V
= 5V
= 500mA
= I
= 80µs
OUT
2V/div
1A/div
V
I
I
t
GSMB
LIM
200mV/div
200mV/div
V
IN
= 515.63mA
FLED1 FLED2
HC_TRM
I
IN
V
INCREASES TO
IN
THE THRESHOLD
I
500mA/div
500mA/div
FLED1
V
= 5V
OUT
I
= 750mA
= 3.0V
FLED1
I
FLED1
V
V
LB_TH
DISABLED
= 50ms
LB_HYS
TMR_DUR
I
0mA
FLED2
t
1ms/div
10ms/div
OUTPUT VOLTAGE LINE REGULATION
(MAX8834Y)
OUTPUT VOLTAGE LINE REGULATION
(MAX8834Z)
5.02
5.01
5.00
4.99
4.98
4.97
5.02
5.01
5.00
4.99
4.98
4.97
V
= 5V
V
= 5V
OUT
OUT
I
= 16mA
OUT
I
= 16mA
OUT
I
= 250mA
OUT
I
= 250mA
I
= 750mA
OUT
OUT
I
= 750mA
4.0
OUT
2.5
3.0
3.5
INPUT VOLTAGE (V)
4.5
2.5
3.0
3.5
INPUT VOLTAGE (V)
4.0
4.5
Maxim Integrated
9
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Typical Operating Characteristics (continued)
(Circuit of Figure 1, V = 3.6V, V
= 3.8V, V
= 3.0V, T = +25°C, unless otherwise noted.)
DD A
IN
OUT
OUTPUT VOLTAGE LOAD REGULATION
OUTPUT VOLTAGE LOAD REGULATION
(MAX8834Y)
(MAX8834Z)
5.02
5.01
5.00
4.99
4.98
4.97
4.96
5.02
5.01
5.00
4.99
4.98
4.97
4.96
V
= 5V
10
OUT
V
= 5V
OUT
1
100
1000
10,000
1
10
100
1000
10,000
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
INPUT CURRENT LIMIT
INPUT CURRENT LIMIT
vs. PROGRAMMED OUTPUT VOLTAGE
vs. PROGRAMMED VALUE
580
570
560
550
540
530
520
510
500
1000
800
600
400
200
0
I
= 500mA
LIM
V
= 5V
OUT
IDEAL LINE
0
200
400
600
800
3.7
4.0
4.3
4.6
4.9
5.2
PROGRAMMED VALUE (mA)
PROGRAMMED OUTPUT VOLTAGE (V)
10
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Pin Description
PIN
NAME
FUNCTION
Regulator Output. Connect OUT to the anodes of the external LEDs. Bypass OUT to PGND with a 10µF
ceramic capacitor. OUT is connected to LX through an internal 10kꢀ resistor during shutdown.
A1, B1
OUT
Inductor Connection. Connect LX to the switched side of the inductor. LX is internally connected to
the drains of the internal MOSFETs. LX is connected to OUT through an internal 10kꢀ resistor during
shutdown.
A2, B2
LX
Power Ground. Connect PGND to AGND and to the input capacitor ground. Connect PGND to the PCB
ground plane.
A3, B3
A4
PGND
IN
Analog Supply Voltage Input. The input voltage range is 2.5V to 5.5V. Bypass IN to AGND and PGND
with a 10µF ceramic capacitor as close as possible to the IC. IN is high impedance during shutdown.
Logic Input Supply Voltage. Connect V to the logic supply driving SCL, SDA, LED_EN, and GSMB.
DD
2
Bypass V to AGND with a 0.1µF ceramic capacitor. When V is below the UVLO, the I C registers
A5
V
DD
DD
DD
reset and the step-up converter turns off.
2
B4
B5
SCL
I C Clock Input. Data is read on the rising edge of SCL.
Analog Ground. Connect AGND to PGND and to the input capacitor ground. Connect AGND to the PCB
ground plane.
AGND
Compensation Input. See the Compensation Network Selection section for details. COMP is internally
pulled to AGND through a 180ꢀ resistor in shutdown.
C1
COMP
FGND
C2, D2
FLED1/FLED2 and INDLED Power Ground. Connect FGND to PGND.
LED Enable Logic Input. LED_EN controls FLED1, FLED2, and INDLED, depending on control bits
written into the LED_CNTL register. See the LED_EN Control register description for an explanation of
this input function. LED_EN has an internal 800kꢀ pulldown resistor to AGND.
C3
C4
LED_EN
GSM Blank Signal. Assert GSMB to reduce the current regulator settings according to the values
programmed into the GSMB_CUR register. The status of the flash safety timer and the flash/movie
mode values in the current regulator registers are not affected by the GSMB state. Connect GSMB to
the PA module enable signal or other suitable logic signal that indicates a GSM transmit is in
process. Polarity of this signal is set by a bit in the GSMB_CUR register (default is active-high).
GSMB has an internal 800kꢀ pulldown resistor to AGND.
GSMB
2
I C Data Input. Data is read on the rising edge of SCL and data is clocked out on the falling edge of
C5
D1
SDA
SCL.
2
FLED2 Current Regulator. Current flowing into FLED2 is based on the internal I C registers
FLASH2_CUR and MOVIE_CUR. Connect FLED2 to the cathode of an external flash LED or LED
module. FLED2 is high impedance during shutdown. If unused, connect FLED2 to ground.
FLED2
2
FLED1 Current Regulator. Current flowing into FLED1 is based on the internal I C registers
FLASH1_CUR and MOVIE_CUR. Connect FLED1 to the cathode of an external flash LED or LED
module. FLED1 is high impedance during shutdown. If unused, connect FLED1 to ground.
D3
D4
D5
FLED1
INDLED
NTC
2
INDLED Current Regulator. Current flowing into INDLED is based on the internal I C registers
IND_CUR. Connect INDLED to the cathode of an external indicator LED. INDLED is high impedance
during shutdown. If unused, connect INDLED to ground.
NTC Bias Output. NTC provides 20µA to bias the NTC thermistor. The NTC voltage is compared to the
trip threshold programmed by the NTC_CNTL register. NTC is high impedance during shutdown.
Connect NTC to IN if not used. See the Finger-Burn Protection (NTC) section for details.
Maxim Integrated
11
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
see Tables 3 and 4). The movie mode provides continu-
Detailed Description
2
ous lighting when enabled through I C or LED_EN.
The MAX8834Y/MAX8834Z flash drivers integrate an
adaptive 1.5A PWM step-up DC-DC converter, two
750mA white LED camera flash/movie current regula-
tors, and a 16mA indicator LED current regulator. An
When the flash mode is enabled, a flash safety timer,
2
programmable from 50ms to 800ms through I C, limits
the duration of the flash mode. Once the flash safety
timer expires, the current regulators return to movie
mode if movie mode was active when a flash event was
triggered. The flash mode has priority over the movie
mode.
2
I C interface controls individual output on/off, the step-
up output voltage setting, the movie/flash current, and
the flash timer duration settings.
Step-Up Converter (LX, OUT, COMP, PGND)
The MAX8834Y/MAX8834Z include a fixed-frequency,
PWM step-up converter that supplies power to the flash
LEDs. The output voltage is programmable from 3.7V to
Flash Safety Timer
The flash safety timer is activated any time flash mode is
2
selected, either with LED_EN or through the I C interface.
2
The flash safety timer, programmable from 50ms to
5.2V (in 100mV steps) through the I C interface. The
2
800ms through I C, limits the duration of the flash mode
output voltage can also be set adaptively based on the
LED forward voltage. The step-up converter switches
an internal power MOSFET and synchronous rectifier at
a constant 2MHz or 4MHz frequency, with varying duty
cycle up to 75%, to maintain constant output voltage as
the input voltage and load vary. Internal circuitry pre-
vents any unwanted subharmonic switching by forcing
a minimum 7% (typ) duty cycle.
2
in case LED_EN is stuck high or the I C command to
turn off has not been sent within the programmed flash
safety timer duration. This timer can be configured to
operate either in one-shot mode or maximum flash
duration mode (see Table 9). In one-shot mode, the
flash function is initiated on the rising edge of LED_EN
2
(or I C bit) and terminated based on the programmed
value of the safety timer (see Figure 1). In the maximum
flash timer mode, flash function remains enabled as
long as LED_EN (or I C bit) is high, unless the prepro-
grammed safety timer times out (see Figure 2).
When the step-up converter is set to dropout mode, the
internal synchronous rectifier is driven fully on, keeping
the voltage at OUT equal to the LX input. This mode
provides the lowest current consumption when driving
LEDs with low forward voltage.
2
Once the flash mode is disabled, by either LED_EN,
I C, or flash safety timer, the flash has to be off for a
minimum time (flash safety timer reset inhibit period),
before it can be reinitiated (see Figure 3). This prevents
spurious events from re-enabling the flash mode.
2
The output voltage is internally monitored for a fault
condition. If the output voltage drops below 8% (typ) of
the nominal programmed value, a POK fault is indicat-
ed in STATUS1 register bit 5. This feature is disabled if
the step-up converter is set to operate in adaptive
mode.
Indicator Current Regulator (INDLED)
A low-dropout linear current regulator from INDLED to
FGND sinks current from the cathode terminal of the
Overvoltage Protection
2
indicator LED. The INDLED current is regulated to I C
The MAX8834Y/MAX8834Z include a comparator to
programmable levels up to 16mA. Programmable con-
trol is provided for ramp-up (OFF to ON) and ramp-
down (ON to OFF) times, as well as blink rate and duty
cycle. The user can choose to enable or disable the
ramp time and blink rate features. See Tables 6, 7, and
8 for more information.
monitor the output voltage (V
) during adaptive
OUT
mode operation of the step-up converter. If at anytime
the output voltage exceeds a maximum threshold of
5.5V, the COMP capacitor is discharged until the output
voltage is reduced by the 200mV (typ) hysteresis. Once
the output voltage drops below this threshold, normal
charging of the COMP capacitor is resumed.
INDLED Blink Function
INDLED current regulator is able to generate a blink
function. The OFF and ON time for INDLED are set
Flash Current Regulator
(FLED1 and FLED2)
2
using the I C interface. See Figure 4.
A low-dropout linear current regulator from FLED1/
FLED2 to FGND sinks current from the cathode terminal
of the flash LED(s). The FLED1/FLED2 current is regu-
INDLED Ramp Function
The INDLED current regulator output provides ramp-up/
down for smooth transition between different brightness
settings. The ramp-up/down times are controlled by the
2
lated to I C programmable levels for movie mode (up to
125mA, see Table 5) and flash mode (up to 750mA,
12
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
ENABLING OF FLASH MODE BY
2
LED_EN OR I C CONTROL
ONE-SHOT FLASH TIMER
ONE-SHOT FLASH TIMER
Figure 1. One-Shot Flash-Timer Mode
ENABLING OF FLASH MODE BY
2
LED_EN OR I C CONTROL
MAXIMUM FLASH
SAFETY TIMER
MAXIMUM FLASH TIMER
Figure 2. Maximum Flash-Timer Mode
ENABLING OF FLASH MODE BY
2
LED_EN OR I C CONTROL
30ms
Figure 3. Flash Safety Timer Reset Inhibit Period
I
IND[4:0]
t
t
IND_ON
IND_OFF
Figure 4. Blink Function Timing
IND_RU and IND_RD control bits, and the ramp func-
tion is enabled/disabled by the IND_RP_EN bit. The
current regulator increases/decreases the current one-
Combining BLINK Timer and Ramp Function
When using the ramp function for INDLED together with
the blink timer, keep the ramp-up timer shorter than the
ON blink timer and the ramp-down timer shorter than
the OFF timer. Failing to comply with this results in the
step every t
/32 until 0mA or IND[4:0] current is
RAMP
reached. See Figures 5 and 6.
Maxim Integrated
13
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
128ms
256ms
512ms
1024ms
I
= FULL SCALE
INDLED
I
= 1/2 SCALE
0mA
INDLED
Figure 5. Ramp-Up Behavior
I
= FULL SCALE
INDLED
I
= 1/2 SCALE
0mA
INDLED
128ms
256ms
512ms
1024ms
Figure 6. Ramp-Down Behavior
t
t
t
t
t
IND_OFF
IND_OFF
IND_ON
IND_OFF
IND_ON
I
= IND_LED[4:0]
IND_LED
I
I
= CODE 0111
= CODE 0011
IND_LED
IND_LED
I
= OFF
IND_LED
t
IND_RU
t
IND_RD
t =
t =
32
32
Figure 7. Combining RAMP Function and Blink Timer
programmed current not being reached during the ON
time, or the INDLED current not returning to 0mA during
the OFF time. See Figure 7.
If FLED1/FLED2 is enabled for both movie and flash
modes at the same time, flash mode has priority. Once
the safety timer expires, the current regulator then
returns to the movie mode.
t
IND_RU
32
Watchdog Timer
t
≥
(IND_LED +1)
(IND_LED +1)
IND_ON
The MAX8834Y/MAX8834Z include a watchdog timer
2
function that can be programmed using the I C inter-
t
IND_RD
32
t
≥
face from 4 seconds to 16 seconds with a 4-second
step. If the watchdog timer expires, the MAX8834Y/
MAX8834Z interpret it as an indication that the system
is no longer responding and enters safe mode. In safe
mode, the MAX8834Y/MAX8834Z disable all current
regulators and the step-up DC-DC converter to prevent
IND_OFF
where IND_LED is the code from 0 to 31 specified in
the IND_LED[4:0].
LED Enable Input (LED_EN)
The LED_EN logic input can enable/disable the FLED1,
FLED2, and INDLED current regulators. It can be
programmed to control movie mode, flash mode, and
indicator mode by using the IND_EN, MOVIE_EN,
and FLASH_EN bits, respectively. See Table 8 for
more information.
2
potential damage to the system. The I C setting for the
respective registers does not change, therefore, reset-
ting the watchdog timer reverts the MAX8834Y/
MAX8834Z back to the state present before entering
safe mode.
14
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
WATCHDOG
TIMEOUT
SUSPENDING ALL
WATCHDOG
WATCHDOG
WATCHDOG
WATCHDOG
CURRENT
TIMER ENABLED
TIMER RESET
TIMER RESET
TIMER RESET
REGULATIONS
WDT_RST IS
CLEARED
2
(I C) WDT_EN
2
(I C) WDT_RST
WATCHDOG TIMER
LED_EN
I
OR
FLED_
I
INDLED
t < WDT_DUR[1:0]
t < WDT_DUR[1:0]
t < WDT_DUR[1:0]
t > WDT_DUR[1:0]
Figure 8. Watchdog Timer Timing Diagram 1
WATCHDOG
TIMEOUT
SUSPENDING ALL
CURRENT
REGULATIONS
WATCHDOG
TIMER ENABLED
WATCHDOG
TIMER RESET
WATCHDOG
TIMER RESET
WATCHDOG
TIMER RESET
WDT_RST IS
CLEARED
2
(I C) WDT_EN
2
(I C) WDT_RST
WATCHDOG TIMER
LED_EN
I
OR
FLED_
I
INDLED
t < WDT_DUR[1:0]
t < WDT_DUR[1:0]
t < WDT_DUR[1:0]
t > WDT_DUR[1:0]
Figure 9. Watchdog Timer Timing Diagram 2
Setting the WDT_EN bit to 1 in the TMR_DUR register
(Table 9) enables the watchdog timer. Resetting the
watchdog timer is achieved by the rising or falling edge
of LED_EN or by setting bit 0 in the WDT_RST register
(Table 14). See Figures 8 and 9 for two examples of
watchdog timer timing diagrams.
Maxim Integrated
15
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
GSMB EVENT
GSMB (ACTIVE-HIGH)
INPUT CURRENT
PREDEFINED INPUT CURRENT
LIMIT DURING GSMB
FLED1/FLED2 DECREASED ONE
LSB SINCE I > I
IN LIM[3:0]
FLED1/FLED2 INCREASED
ONE LSB SINCE I < I
IN LIM[3:0]
FLED2 OUTPUT
CURRENT
FLED1 OUTPUT
CURRENT
FLASH1_CUR
SETTING
TIME
HC_TMR[1:0]
1µs AFTER GSMB
ACTIVATED, FLED_ GOES
TO THE MINIMUM SETTING
1µs AFTER GSMB
DEACTIVATED, FLED_ GOES
TO THE PREVIOUS SETTING
Figure 10. Input Current Limit During GSMB Event
then start increasing the FLED1 and FLED2 current by
one LSB steps, at a time interval set by HC_TMR[1:0]
(see Table 11). The increasing continues until either the
predefined FLED1/FLED2 current setting is reached or
the input current exceeds the maximum predefined
input current limit during a GSMB event. When the input
current exceeds the predefined input current limit, the
FLED1/FLED2 current is reduced by one LSB. The
MAX8834Y/MAX8834Z continue to adjust the FLED1
and FLED2 up and down depending on the input cur-
rent limit as long as the GSMB event is present. See
Figure 10 for more detailed information.
GSM Blank Function (GSMB)
The GSMB input is provided to allow the flash current to
be momentarily reduced during a GSM transmit to
reduce the peak current drawn from the battery. The
input current limit ensures that the maximum possible
output current is always provided, regardless of the
input voltage and the LED forward voltages.
When a GSMB event is triggered, the FLED1 and
FLED2 current regulators go to the lowest setting to
ensure the current drawn from the battery is quickly
reduced to a safe level. The MAX8834Y/MAX8834Z
16
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
To use this feature, connect the logic signal used to
enable the PA, or equivalent, to the GSMB input.
Assertion of this signal does not change the current sta-
tus of the flash safety timer or the flash current values
plus a predefined hysteresis (V
). If it is still
LB_HYS
below V
+ V
, the FLED1/FLED2 current
LB_HYS
LB_TH
regulators reduce their output current again to ensure
that minimum input voltage is available for the system.
2
stored in the I C registers. Once the signal is deassert-
If the input voltage is above V
+ V
, the cur-
LB_TH
LB_HYS
ed, the current regulators change back to their previ-
ously programmed values. Polarity of this signal is
controlled through bit 6 in the GSMB_CUR register
(Table 11). The default is active-high.
rent regulator increases the output current by one step
(if it is less than the user-defined output current). To
disable the hysteresis, set LB_HYS[1:0] to 11. In this
case, after the FLED1/FLED2 current is reduced, it
stays at the current setting. Figures 12, 13, and 14
show examples of MAXFLASH function operation. See
Tables 12 and 13 for control register details.
Finger-Burn Protection (NTC)
An NTC input is provided for the (optional) finger-burn
protection feature. To use this feature, connect a 100kΩ
NTC with B = 4550 between NTC and AGND. NTC
sources 20µA current and the voltage established by
this current and the NTC resistance is compared inter-
nally to a voltage threshold in the range of 200mV to
550mV, programmed through bits [2:0] of the NTC
Control register (see Table 10).
The MAXFLASH function continues for the entire dura-
tion of the FLASH/MOVIE event to ensure that the
FLASH/MOVIE output current is always maximized for
the specific operating conditions.
Undervoltage Lockout
The MAX8834Y/MAX8834Z contain undervoltage lock-
If the voltage on the NTC pin falls below the programmed
threshold during a flash event, the flash cycle is immedi-
ately terminated, and an indication is latched through bit 3
in the STATUS1 register (see Table 15).
out (UVLO) circuitry that disables the IC until V is
IN
greater than 2.3V (typ). Once V rises above 2.3V
IN
(typ), the UVLO circuitry does not disable the IC until
V
falls below the UVLO threshold minus the hysteresis
IN
voltage. The MAX8834Y/MAX8834Z also contain a V
DD
To disable this function, clear bit 3 (enable bit) in the
NTC Control register.
UVLO circuitry that monitors the V
V
the logic registers are reset to their default states. The
logic registers are only reset in a V
and not an IN UVLO condition.
voltage. When the
DD
voltage falls below 1.4V (typ), the contents of all
DD
MAXFLASH Function
During high load currents, the battery voltage momen-
tarily drops due to its internal ESR, together with the
serial impedance from the battery to the load. For
equipment requiring a minimum voltage for stable oper-
ation, the battery ESR needs to be calculated to esti-
mate the maximum battery current that maintains the
battery voltage above the critical threshold. Due to the
complicated measurement of the battery ESR, the
MAX8834Y/MAX8834Z feature the MAXFLASH function
to prevent the battery voltage from dropping below the
threshold voltage. See Figure 11 for details.
UVLO condition
DD
t
LB_TMR
I
OUT_MAX
IN
DOWN
V
LB_TH
CURRENT
REGULATOR
The MAX8834Y/MAX8834Z input voltage is monitored
during a FLASH/MOVIE event. If the input voltage
UP
drops below a predefined threshold (V
), it indi-
LB_TH
cates that the FLASH/MOVIE event is drawing more
current than the battery can support. As a result, the
FLED1/FLED2 current regulators start decreasing their
output currents by one step. Therefore, the input cur-
rent is reduced and the input voltage starts to rise due
to the internal battery ESR. The input voltage is then
V
V
LB_HYS
LB_TH
sampled again after t
and compared to V
LB_TH
Figure 11. Block Diagram of MAXFLASH Function
LB_TMR
Maxim Integrated
17
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
V
+ V
LB_HYS
LB_TH
V
LB_TH
t
LB_TMR
TIME
Figure 12. Example 1 of MAXFLASH Function Operation
REDUCTION IN BATTERY CURRENT CAUSED
BY OTHER SYSTEM
V
+ V
LB_HYS
LB_TH
V
I
LB_TH
MAX
t
LB_TMR
TIME
Figure 13. Example 2 of MAXFLASH Function Operation
REDUCTION IN BATTERY CURRENT
CAUSED BY OTHER SYSTEM
FLASH CURRENT IS NOT INCREASED
AGAIN SINCE LB_HYS = 11
V
+ V
LB_HYS
LB_TH
V
LB_TH
I
MAX
t
LB_TMR
TIME
Figure 14. Example 3 of MAXFLASH Function Operation with Hysteresis Disabled
18
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
2
FLED2 regulators must be disabled through I C to
avoid a fault detection from an open or short.
Soft-Start
The step-up converter implements a soft-start to control
inrush current when it turns on. It soft-starts by charging
Open/Short Detection
The MAX8834Y/MAX8834Z monitor the FLED1, FLED2,
and INDLED voltage to detect any open or short LEDs.
A short fault is detected when the voltage rises above
C
with a 100µA current source. During this time,
COMP
the internal MOSFET is switching at the minimum duty
cycle. Once V rises above 1V, the duty cycle
COMP
increases until the output voltage reaches the desired
regulation level. COMP is pulled to AGND with a 180Ω
(typ) internal resistor during IN, UVLO, dropout mode,
or shutdown. See the Typical Operating Characteristics
for an example of soft-start operation. Soft-start is reini-
tiated after UVLO or if the step-up converter is re-
enabled after shutdown or dropout mode.
V
- 1V (typ), and an open fault is detected when
OUT
the voltage falls below 100mV. The fault detection cir-
cuitry is only activated when the corresponding current
regulator is enabled and provides a continuous moni-
tor of the current regulator condition. Once a fault is
detected, the corresponding current regulator is dis-
abled and the status is latched into the corresponding
fault register bit (see Table 15). This allows the proces-
sor to determine the MAX8834Y/MAX8834Z operating
condition.
Shutdown and Standby
The MAX8834Y/MAX8834Z are in shutdown when either
V
or V
are in UVLO. In shutdown, supply current is
IN
DD
reduced to 0.1µA (typ). When V is above its UVLO
IN
Thermal Shutdown
Thermal shutdown limits total power dissipation in the
MAX8834Y/MAX8834Z. When the junction temperature
exceeds +160°C (typ), the IC turns off, allowing itself to
cool. The IC turns on and begins soft-start after the junc-
tion temperature cools by 20°C. This results in a pulsed
output during continuous thermal overload conditions.
threshold, but V
is below its UVLO threshold, the IC
DD
disables its internal reference, keeps all registers reset,
turns the step-up converter off, and turns the
FLED1/FLED2 current regulators off (high impedance).
Once a logic-level voltage is supplied to V , the IC
DD
2
enters standby condition and is ready to accept I C
commands. The internal MOSFET, synchronous rectifi-
er, and FLED1/FLED2 are also high impedance in
standby.
2
I C Serial Interface
An I C-compatible, 2-wire serial interface controls the
2
Typical shutdown timing characteristics are shown in
the Typical Operating Characteristics.
step-up converter output voltage, flash, movie, and
indicator current settings, flash duration, and other
parameters. The serial bus consists of a bidirectional
serial-data line (SDA) and a serial-clock input (SCL).
The MAX8834Y/MAX8834Z are slave-only devices, rely-
ing upon a master to generate a clock signal. The mas-
ter initiates data transfer to and from the MAX8834Y/
Parallel Connection of Current Regulators
The FLED1/FLED2 current regulators can be connected
in parallel as long as the system software properly sets
the current levels for each regulator. Unused current
regulators may be connected to ground. The FLED1/
SDA
t
BUF
t
SU,STA
t
SU,DAT
t
HD,STA
t
LOW
t
SU,STO
t
HD,DAT
t
SCL
t
HIGH
HD,STA
t
t
F
R
START CONDITION
REPEATED START CONDITION
STOP
CONDITION
START
CONDITION
Figure 15. 2-Wire Serial Interface Timing Detail
Maxim Integrated
19
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
SCL
SDA
DATA LINE STABLE
DATA VALID
DATA ALLOWED TO
CHANGE
STOP
CONDITION
(P)
START
CONDITION
(S)
Figure 16. Bit Transfer
MAX8834Z and generates SCL to synchronize the data
transfer (Figure 15).
START and STOP Conditions
Both SCL and SDA remain high when the bus is not
busy. The master signals the beginning of a transmis-
sion with a START (S) condition by transitioning SDA
from high to low while SCL is high. When the master
has finished communicating with the MAX8834Y/
MAX8834Z, it issues a STOP (P) condition by transition-
ing SDA from low to high while SCL is high. The bus is
then free for another transmission (Figure 17). Both
START and STOP conditions are generated by the bus
master.
2
I C is an open-drain bus. Both SDA and SCL are bidi-
rectional lines, connected to a positive supply voltage
through a pullup resistor. They both have Schmitt trig-
gers and filter circuits to suppress noise spikes on the
bus to assure proper device operation.
A bus master initiates communication with the
MAX8834Y/MAX8834Z as a slave device by issuing a
START (S) condition followed by the MAX8834Y/
MAX8834Z address. The MAX8834Y/MAX8834Z
address byte consists of 7 address bits and a read/
write bit (R/W). After receiving the proper address, the
MAX8834Y/MAX8834Z issue an acknowledge bit by
pulling SDA low during the ninth clock cycle.
Acknowledge
The acknowledge bit is used by the recipient to hand-
shake the receipt of each byte of data (Figure 18). After
data transfer, the master generates the acknowledge
clock pulse and the recipient pulls down the SDA line
during this acknowledge clock pulse so the SDA line
stays low during the high duration of the clock pulse.
When the master transmits the data to the
MAX8834Y/MAX8834Z, it releases the SDA line and the
MAX8834Y/MAX8834Z take control of the SDA line and
generate the acknowledge bit. When SDA remains high
during this 9th clock pulse, this is defined as the not
acknowledge signal. The master can then generate
either a STOP condition to abort the transfer, or a
repeated START condition to start a new transfer.
Slave Address
The MAX8834Y/MAX8834Z act as a slave transmitter/
receiver. Its slave address is 0x94 for write operations
and 0x95 for read operations.
Bit Transfer
Each data bit, from the most significant bit to the least
significant bit, is transferred one by one during each
clock cycle. During data transfer, the SDA signal is
allowed to change only during the low period of the
SCL clock and it must remain stable during the high
period of the SCL clock (Figure 16).
20
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
SDA BY MASTER
D0
D7
D6
SDA
SCL
NOT ACKNOWLEDGE
SDA BY SLAVE
SCL
ACKNOWLEDGE
8
1
2
9
CLOCK PULSE FOR
ACKNOWLEDGEMENT
START CONDITION
START
STOP
CONDITION
CONDITION
Figure 17. START and STOP Conditions
Figure 18. Acknowledge
Write Operations
Use the following procedure to write to a sequential
block of registers:
The MAX8834Y/MAX8834Z recognize the write byte
protocol as defined in the SMBus™ specification and
shown in section A of Figure 19. The write byte proto-
1) The master sends a start command.
2) The master sends the 7-bit slave address followed
by a write bit.
2
col allows the I C master device to send 1 byte of data
to the slave device. The write-byte protocol requires a
register pointer address for the subsequent write. The
MAX8834Y/MAX8834Z acknowledge any register
pointer even though only a subset of those registers
actually exists in the device. The write byte protocol is
as follows:
3) The addressed slave asserts an acknowledge by
pulling SDA low.
4) The master sends the 8-bit register pointer of the
first register to write.
5) The slave acknowledges the register pointer.
6) The master sends a data byte.
1) The master sends a start command.
2) The master sends the 7-bit slave address followed
by a write bit.
7) The slave updates with the new data.
8) The slave acknowledges the data byte.
3) The addressed slave asserts an acknowledge by
pulling SDA low.
9) Steps 6 to 8 are repeated for as many registers in
the block, with the register pointer automatically
incremented each time.
4) The master sends an 8-bit register pointer.
5) The slave acknowledges the register pointer.
6) The master sends a data byte.
10) The master sends a STOP condition.
Read Operations
The method for reading a single register (byte) is shown
in section A of Figure 20. To read a single register:
7) The slave updates with the new data.
8) The slave acknowledges the data byte.
9) The master sends a STOP (P) condition.
1) The master sends a start command.
In addition to the write-byte protocol, the MAX8834Y/
MAX8834Z can write to multiple registers as shown in
2) The master sends the 7-bit slave address followed
by a write bit.
2
section B of Figure 19. This protocol allows the I C
3) The addressed slave asserts an acknowledge by
pulling SDA low.
master device to address the slave only once and then
send data to a sequential block of registers starting at
the specified register pointer.
4) The master sends an 8-bit register pointer.
SMBus is a trademark of Intel Corp.
Maxim Integrated
21
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
LEGEND
MASTER TO
SLAVE
SLAVE TO
MASTER
A. WRITING TO A SINGLE REGISTER WITH THE WRITE BYTE PROTOCOL
1
7
1
0
1
8
1
8
1
1
NUMBER OF BITS
S
SLAVE ADDRESS
A
REGISTER POINTER
A
DATA
A
P
R/W
B. WRITING TO MULTIPLE REGISTERS
NUMBER OF BITS
1
7
1
1
8
1
8
1
8
1
...
S
SLAVE ADDRESS
0
A
REGISTER POINTER X
A
DATA X
A
DATA X+1
A
R/W
NUMBER OF BITS
8
1
8
1
...
DATA X+n-1
A
DATA X+n
A
P
Figure 19. Writing to the MAX8834Y/MAX8834Z
5) The slave acknowledges the register pointer.
3) The addressed slave asserts an acknowledge by
pulling SDA low.
6) The master sends a REPEATED START (Sr) condition.
4) The master sends an 8-bit register pointer of the
first register in the block.
7) The master sends the 7-bit slave address followed
by a read bit.
5) The slave acknowledges the register pointer.
6) The master sends a REPEATED START condition.
8) The slave asserts an acknowledge by pulling SDA
low.
9) The slave sends the 8-bit data (contents of the reg-
ister).
7) The master sends the 7-bit slave address followed
by a read bit.
10) The master asserts an acknowledge by pulling SDA
low.
8) The slave asserts an acknowledge by pulling SDA
low.
11) The master sends a STOP (P) condition.
9) The slave sends the 8-bit data (contents of the reg-
ister).
In addition, the MAX8834Y/MAX8834Z can read a block
of multiple sequential registers as shown in section B of
Figure 20. Use the following procedure to read a
sequential block of registers:
10) The master asserts an acknowledge by pulling SDA
low.
11) Steps 9 and 10 are repeated for as many registers
in the block, with the register pointer automatically
incremented each time.
1) The master sends a start command.
2) The master sends the 7-bit slave address followed
by a write bit.
12) The master sends a STOP condition.
22
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
LEGEND
MASTER TO
SLAVE
SLAVE TO
MASTER
A. READING A SINGLE REGISTER
1
7
1
0
1
8
1
1
8
1
1
8
1
1
NUMBER OF BITS
S
SLAVE ADDRESS
A
REGISTER POINTER
A
Sr
SLAVE ADDRESS
1
A
DATA
A
P
R/W
B. READING MULTIPLE REGISTERS
NUMBER OF BITS
1
7
1
1
8
1
1
8
1
8
1
1
1
...
S
SLAVE ADDRESS
0
A
REGISTER POINTER X
A
Sr
SLAVE ADDRESS
A
DATA X+1
A
R/W
R/W
8
1
8
1
8
1
1
NUMBER OF BITS
...
A
...
DATA X+1
DATA X+n-1
A
DATA X+n
A
P
Figure 20. Reading from the MAX8834Y/MAX8834Z
Maxim Integrated
23
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Table 1. Register Map
REGISTER
ADDRESS (hex)
NAME
TABLE
TYPE
DESCRIPTION
Step-up converter control
BOOST_CNTL
Table 2
Table 3
Table 4
Table 5
—
00
01
02
03
04
05
06
07
08
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
FLASH1_CUR
FLED1 flash current control
FLED2 flash current control
FLED1 and FLED2 movie current control
Reserved for future use
FLASH2_CUR
MOVIE_CUR
Reserved for future use
IND_CUR
Table 6
—
Indicator LED current control
Reserved for future use
Reserved for future use
IND_CNTL
Table 7
—
Indicator LED ramp and blink control
Reserved for future use
Reserved for future use
FLED1, FLED2, and INDLED on/off and mode control,
and definition of LED_EN logic input function
LED_CNTL
Table 8
09
R/W
TMR_DUR
Table 9
Table 10
Table 11
Table 12
Table 13
Table 14
Table 15
Table 16
—
0A
0B
0C
0D
0E
16
17
18
19
1A
1B
R/W
R/W
R/W
R/W
R/W
R/W
R
Watchdog timer and flash safety timer control
NTC function control
NTC_CNTL
GSMB_CUR
MAXFLASH1
MAXFLASH2
WDT_RST
FLED1 and FLED2 current control during GSM transmit
MAXFLASH function register 1
MAXFLASH function register 2
Watchdog timer reset
STATUS1
Status register
STATUS2
R
Status register
Reserved for future use
CHIP_ID1
R/W
R
Reserved for future use
Table 17
Table 18
Die type information
CHIP_ID2
R
Die type and mask revision information
24
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Table 2. BOOST_CNTL
This register contains step-up converter control values.
REGISTER NAME
Address
BOOST_CNTL
0x00
Reset Value
Type
0x00
Read/write
—
Special Features
BIT
NAME
DESCRIPTION
DEFAULT VALUE
B7 (MSB)
—
Reserved for future use
0
0 = Step-up converter off
1 = Step-up converter on
B6
B5
BOOST_EN
0
00 = Step-up voltage set adaptively
01 = Step-up voltage set programmatically according to
BOOST_CNTL[3:0]
BOOST_MODE
00
10 = Step-up converter runs in dropout
B4
B3
B2
11 = Step-up converter automatically changes between adaptive
regulation and dropout mode depending on operating conditions
0000 = 3.7V
0001 = 3.8V
0010 = 3.9V
0011 = 4.0V
0100 = 4.1V
0101 = 4.2V
0110 = 4.3V
0111 = 4.4V
1000 = 4.5V
1001 = 4.6V
1010 = 4.7V
1011 = 4.8V
1100 = 4.9V
1101 = 5.0V
1110 = 5.1V
1111 = 5.2V
BOOST_CNTL[3:0]
0000
B1
B0 (LSB)
Maxim Integrated
25
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Table 3. FLASH1_CUR
This register contains FLED1 flash current control values.
REGISTER NAME
Address
FLASH1_CUR
0x01
Reset Value
Type
0x00
Read/write
—
Special Features
BIT
NAME
DESCRIPTION
DEFAULT VALUE
FLED1 Flash Mode Current Setting
00000 = 23.44mA
00001 = 46.88mA
00010 = 70.32mA
B7 (MSB)
00011 = 93.76mA
00100 = 117.20mA
00101 = 140.64mA
00110 = 164.08mA
00111 = 187.52mA
01000 = 210.96mA
01001 = 234.40mA
01010 = 257.84mA
01011 = 281.28mA
01100 = 304.72mA
01101 = 328.16mA
01110 = 351.60mA
B6
B5
B4
B3
FLASH1[4:0] 01111 = 375.04mA
10000 = 398.48mA
10001 = 421.92mA
10010 = 445.36mA
10011 = 468.80mA
10100 = 492.24mA
10101 = 515.68mA
10110 = 539.12mA
10111 = 562.56mA
11000 = 586.00mA
11001 = 609.44mA
11010 = 632.88mA
11011 = 656.32mA
11100 = 679.76mA
11101 = 703.20mA
11110 = 726.56mA
11111 = 750.00mA
00000
B2
B1
—
—
—
Reserved for future use
Reserved for future use
Reserved for future use
—
—
—
B0 (LSB)
26
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Table 4. FLASH2_CUR
This register contains FLED2 flash current control values.
REGISTER NAME
Address
FLASH2_CUR
0x02
Reset Value
Type
0x00
Read/write
—
Special Features
BIT
NAME
DESCRIPTION
DEFAULT VALUE
FLED2 Flash Mode Current Setting
00000 = 23.44mA
00001 = 46.88mA
00010 = 70.32mA
00011 = 93.76mA
00100 = 117.20mA
00101 = 140.64mA
00110 = 164.08mA
00111 = 187.52mA
01000 = 210.96mA
01001 = 234.40mA
01010 = 257.84mA
01011 = 281.28mA
01100 = 304.72mA
01101 = 328.16mA
01110 = 351.60mA
01111 = 375.04mA
10000 = 398.48mA
10001 = 421.92mA
10010 = 445.36mA
10011 = 468.80mA
10100 = 492.24mA
10101 = 515.68mA
10110 = 539.12mA
10111 = 562.56mA
11000 = 586.00mA
11001 = 609.44mA
11010 = 632.88mA
11011 = 656.32mA
11100 = 679.76mA
11101 = 703.20mA
11110 = 726.56mA
11111 = 750.00mA
B7 (MSB)
B6
B5
B4
FLASH2[4:0]
00000
B3
B2
B1
—
—
—
Reserved for future use
Reserved for future use
Reserved for future use
—
—
—
B0 (LSB)
Maxim Integrated
27
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Table 5. MOVIE_CUR
This register contains FLED1 and FLED2 movie current control values.
REGISTER NAME
Address
MOVIE_CUR
0x03
Reset Value
Type
0x00
Read/write
—
Special Features
BIT
NAME
DESCRIPTION
DEFAULT NAME
B7 (MSB)
—
Reserved for future use
—
FLED1 Movie Mode Current Setting
000 = 15.625mA
B6
001 = 31.250mA
010 = 46.875mA
MOVIE1[2:0]
011 = 62.500mA
100 = 78.125mA
101 = 93.750mA
110 = 109.375mA
111 = 125.000mA
000
—
B5
B4
B3
—
Reserved for future use
FLED2 Movie Mode Current Setting
000 = 15.625mA
001 = 31.250mA
010 = 46.875mA
011 = 62.500mA
B2
B1
MOVIE2[2:0]
000
100 = 78.125mA
101 = 93.750mA
110 = 109.375mA
111 = 125.000mA
B0 (LSB)
28
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Table 6. IND_CUR
This register contains indicator LED current control values.
REGISTER NAME
Address
IND_CUR
0x05
Reset Value
Type
0x00
Read/write
—
Special Features
BIT
NAME
DESCRIPTION
DEFAULT VALUE
B7 (MSB)
—
Reserved for future use
0
INDLED Indicator Blink Timer Enable
0 = Indicator blink is disabled
1 = Indicator blink is enabled
B6
B5
IND_BL_EN
IND_RP_EN
0
0
INDLED Indicator Ramp-Up/Down Enable
0 = Indicator ramp-up/down is disabled
1= Indicator ramp-up/down is enabled
INDLED Indicator Mode Current Setting
00000 = 0.5mA
00001 = 1.0mA
00010 = 1.5mA
00011 = 2.0mA
00100 = 2.5mA
00101 = 3.0mA
00110 = 3.5mA
00111 = 4.0mA
01000 = 4.5mA
01001 = 5.0mA
01010 = 5.5mA
01011 = 6.0mA
01100 = 6.5mA
01101 = 7.0mA
01110 = 7.5mA
01111 = 8.0mA
10000 = 8.5mA
10001 = 9.0mA
10010 = 9.5mA
10011 = 10.0mA
10100 = 10.5mA
10101 = 11.0mA
10110 = 11.5mA
10111 = 12.0mA
11000 = 12.5mA
11001 = 13.0mA
11010 = 13.5mA
11011 = 14.0mA
11100 = 14.5mA
11101 = 15.0mA
11110 = 15.5mA
11111 = 16.0mA
B4
B3
B2
B1
IND[4:0]
00000
B0 (LSB)
Maxim Integrated
29
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Table 7. IND_CNTL
This register contains indicator LED ramp and blink timer control.
REGISTER NAME
Address
IND_CNTL
0x07
Reset Value
Type
0x00
Read/write
—
Special Features
BIT
NAME
DESCRIPTION
DEFAULT VALUE
INDLED Indicator Off Blink Timer Control
00 = 512ms
B7 (MSB)
IND_OFF
01 = 1024ms
00
10 = 2048ms
11 = 4096ms
B6
B5
B4
B3
INDLED Indicator On Blink Timer Control
00 = 128ms
01 = 256ms
10 = 512ms
11 = 1024ms
IND_ON
00
00
00
INDLED Indicator Ramp-Up Timer Control
00 = 128ms
01 = 256ms
10 = 512ms
11 = 1024ms
IND_RU[1:0]
IND_RD[1:0]
B2
B1
INDLED Indicator Ramp-Down Timer Control
00 = 128ms
01 = 256ms
10 = 512ms
11 = 1024ms
B0 (LSB)
30
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Table 8. LED_CNTL
This register contains FLED1, FLED2 and INDLED on/off and mode control.
REGISTER NAME
Address
LED_CNTL
0x09
Reset Value
Type
0x00
Read/write
—
Special Features
BIT
NAME
DESCRIPTION
DEFAULT VALUE
INDLED Indicator Current Regulator Enable
00 = INDLED indicator LED is disabled
B7 (MSB)
IND_EN[1:0]
00
01 = INDLED indicator LED is disabled
10 = INDLED indicator LED is enabled
B6
11 = INDLED indicator LED is controlled by LED_EN input
FLED1/FLED2 MOVIE Mode Current Regulator Enable
000 = FLED1 and FLED2 movie mode disabled
B5
B4
001 = FLED1 movie mode is enabled, FLED2 movie mode is disabled
010 = FLED2 movie mode is enabled, FLED1 movie mode is disabled
011 = FLED1 and FLED2 movie mode is enabled
101 = FLED1 movie mode is controlled by LED_EN, FLED2 movie mode
is disabled
MOVIE_EN[2:0]
000
110 = FLED2 movie mode is controlled by LED_EN, FLED1 movie mode
is disabled
B3
111 = FLED1 and FLED2 movie mode is controlled by LED_EN
FLED1/FLED2 Flash Mode Current Regulator Enable
000 = FLED1 and FLED2 flash mode disabled
B2
001 = FLED1 flash mode is enabled, FLED2 flash mode is disabled
010 = FLED2 flash mode is enabled, FLED1 flash mode is disabled
011 = FLED1 and FLED2 flash mode is enabled
101 = FLED1 flash mode is controlled by LED_EN, FLED2 flash mode is
disabled
FLASH_EN[2:0]
000
B1
110 = FLED2 flash mode is controlled by LED_EN, FLED1 flash mode is
disabled
B0 (LSB)
111 = FLED1 and FLED2 flash mode is controlled by LED_EN
Maxim Integrated
31
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Table 9. TMR_DUR
This register contains watchdog timer and flash safety time-control values.
REGISTER NAME
Address
TMR_DUR
0x0A
Reset Value
Type
0x00
Read/write
—
Special Features
BIT
B7 (MSB)
B6
NAME
DESCRIPTION
DEFAULT VALUE
Enable/Disable Of Watchdog Timer Function
0 = WDT is disabled
WDT_EN
0
1 = WDT is enabled
Watchdog Timer Duration
00 = 4s
WDT_DUR[1:0]
TMR_MODE
00
01 = 8s
10 = 12s
11 = 16s
Safety Timer Control
B5
0 = One-shot mode—generates a flash with a duration of TMR_DUR
2
regardless of LED:EN and I C setting; pulling V low in this
DD
B4
0
condition terminates flash operating and puts the IC into power-down
mode
1 = Maximum timer mode—ensures that flash duration does not exceed
the timer defined in TMR:DUR
Safety Timer Duration Control
0000 = 50ms
0001 = 100ms
0010 = 150ms
0011 = 200ms
B3
B2
0100 = 250ms
0101 = 300ms
0110 = 350ms
TMR_DUR [3:0] 0111 = 400ms
1000 = 450ms
0000
1001 = 500ms
1010 = 550ms
B1
1011 = 600ms
1100 = 650ms
1101 = 700ms
1110 = 750ms
B0 (LSB)
1111 = 800ms
32
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Table 10. NTC_CNTL
This register contains NTC function control values.
REGISTER NAME
Address
NTC_CNTL
0x0B
Reset Value
Type
0x00
Read/write
—
Special Features
BIT
NAME
DESCRIPTION
DEFAULT VALUE
Flash Safety Timer Reset Control
0 = Enable FLASH reset timer, only valid when FLASH mode is
enabled using the LED_EN; LED_EN needs to be pulled low for
minimum 30ms (typ) to reset the flash safety
1 = Disable FLASH reset timer; flash safety timer is reset as soon as
LED_EN is pulled low
B7 (MSB)
FLASH_TMR_CNTL
0
B6
B5
B4
—
—
—
Reserved for future use
Reserved for future use
Reserved for future use
0
0
0
Finger-Burn Feature Enable
0 = Disable NTC function
1 = Enable NTC function
B3
B2
NTC_EN
0
Finger-Burn Threshold Control
000 = 200mV
001 = 250mV
010 = 300mV
NTC[2:0]
011 = 350mV
000
B1
100 = 400mV
101 = 450mV
110 = 500mV
111 = 550mV
B0 (LSB)
Maxim Integrated
33
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Table 11. GSMB_CUR
This register contains FLED1 and FLED2 current control values for the GSMB function.
REGISTER NAME
Address
GSMB_CUR
0x0C
Reset Value
Type
0xC0
Read/write
—
Special Features
BIT
NAME
DESCRIPTION
DEFAULT VALUE
GSM Blank Enable
0 = GSMB input is disabled
1 = GSMB input is enabled
B7 (MSB)
B6
GSMB_EN
1
GSM Blank Polarity Control
0 = GSMB is active-low
1 = GSMB is active-high
GSMB_POL
1
Input Current Limit During GSMB
0000 = 50mA
B5
B4
0001 = 100mA
0010 = 150mA
0011 = 200mA
0100 = 250mA
0101 = 300mA
0110 = 350mA
0111 = 400mA
1000 = 450mA
1001 = 500mA
1010 = 550mA
1011 = 600mA
1100 = 650mA
1101 = 700mA
1110 = 750mA
1111 = 800mA
ILIM[3:0]
0000
B3
B2
GSMB Reset Timer
00 = 10µs
B1
HC_TMR[1:0] 01 = 20µs
10 = 40µs
00
B0 (LSB)
11 = 80µs
34
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Table 12. MAXFLASH1
This register contains MAXFLASH control function.
REGISTER NAME
Address
MAXFLASH1
0x0D
Reset Value
Type
0x00
Read/write
—
Special Features
BIT
NAME
DESCRIPTION
DEFAULT VALUE
MAXFLASH Function Enable
0 = Disabled
B7 (MSB)
LB_EN
0
1 = Low-battery function is enabled
Low-Battery Detection Threshold
00000 = 2.400V [Do not use]
00001 = 2.433V [Do not use]
00010 = 2.466V [Do not use]
00011 = 2.500V
00100 = 2.533V
00101 = 2.566V
00110 = 2.600V
00111 = 2.633V
B6
B5
01000 = 2.666V
01001 = 2.700V
01010 = 2.733V
01011 = 2.766V
01100 = 2.800V
01101 = 2.833V
01110 = 2.866V
LB_TH[4:0]
01111 = 2.900V
10000 = 2.933V
10001 = 2.966V
10010 = 3.000V
10011 = 3.033V
10100 = 3.066V
10101 = 3.100V
10110 = 3.133V
10111 = 3.166V
11000 = 3.200V
11001 = 3.233V
11010 = 3.266V
11011 = 3.300V
11100 = 3.333V
11101 = 3.366V
00000
B4
B3
B2
11110 = 3.400V
11111 = 3.400V
Low-Battery Detection Hysteresis
00 = 100mV
B1
LB_HYS[1:0]
01 = 200mV
00
10 = Reserved for future use
11 = Hysteresis is disabled—flash current is only reduced
B0 (LSB)
Maxim Integrated
35
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Table 13. MAXFLASH2
This register contains MAXFLASH control function.
REGISTER NAME
Address
MAXFLASH2
0x0E
Reset Value
Type
0x00
Read/write
—
Special Features
BIT
B7 (MSB)
B6
NAME
—
DESCRIPTION
DEFAULT VALUE
Reserved for future use
Reserved for future use
Reserved for future use
Reserved for future use
Reserved for future use
Reserved for future use
0
0
0
0
0
0
—
B4
—
B3
—
B3
—
B2
—
Low-Battery Reset Timer
00 = 0.250ms
B1
LB_TMR[1:0] 01 = 0.500ms
10 = Reserved for future use
11 = Reserved for future use
00
B0 (LSB)
Table 14. WDT_RST
This register contains watchdog reset function.
REGISTER NAME
Address
WDT_RST
0x16
Reset Value
Type
0x00
Read/write
—
Special Features
BIT
B7 (MSB)
B6
NAME
—
DESCRIPTION
DEFAULT VALUE
Reserved for future use
Reserved for future use
Reserved for future use
Reserved for future use
Reserved for future use
Reserved for future use
Reserved for future use
0
0
0
0
0
0
0
—
B4
—
B3
—
B3
—
B2
—
B1
—
Watchdog Reset
0 = Default
B0 (LSB)
—
—
1 = Writing a 1 resets the watchdog timer; after writing a 1, this bit is cleared
upon watchdog timer reset
36
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Table 15. STATUS1
This register contains status information.
REGISTER NAME
Address
STATUS1
0x17
N/A
Read
—
Reset Value
Type
Special Features
BIT
NAME
DESCRIPTION
DEFAULT VALUE
NTC Status Readback
0 = NTC status OK
B7 (MSB)
NTC_FLT
0
1 = Fault (short) occurred on NTC
GSMB Status Readback
B6
B5
GSMB
0 = No GSMB event has occurred
1 = GSMB event has occurred
0
0
0
0
0
0
0
POK Window Cooperator Status Readback
0 = Output voltage is within POK window
1 = POK fault has occurred
POK_FLT
Die Temperature Overload Condition Status Readback
0 = Die temp is within spec
1 = Die overtemp event has occurred
B4
OVER_TEMP
NTC_OVT
NTC Status Readback
0 = NTC temperature is within spec
1 = NTC temperature threshold has tripped
B3
INDLED Status Readback
0 = INDLED status is OK
1 = Fault (open/short) has occurred on INDLED
B2
INDLED_FLT
FLED2_FLT
FLED1_FLT
FLED2 Status Readback
0 = FLED2 status is OK
1 = Fault (open/short) has occurred on FLED2
B1
FLED1 Status Readback
0 = FLED1 status is OK
B0 (LSB)
1 = Fault (open/short) has occurred on FLED1
Note: All faults are latched. Bit(s) are cleared after reading register contents. If the fault is still present, the bit is set again.
Maxim Integrated
37
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Table 16. STATUS2
This register contains status information.
REGISTER NAME
Address
STATUS2
0x18
N/A
Reset Value
Type
Read
—
Special Features
BIT
NAME
DESCRIPTION
DEFAULT VALUE
Indication of if MAXFLASH Function Has Been Triggered Since Last
Read Operation of This Register
0 = MAXFLASH event has not occurred
B7 (MSB)
B6
MAXFLASH_STAT
GSMB_ILIM
0
1 = MAXFLASH event has occurred
Indication of if Input Current Limit Has Been Reached During GSMB
Since Last Read Operation of This Register
0 = Input current limit not reached
0
1 = Input current limit reached
B5
B4
—
—
—
—
—
—
Reserved for future use
Reserved for future use
Reserved for future use
Reserved for future use
Reserved for future use
Reserved for future use
0
0
0
0
0
0
B3
B2
B1
B0 (LSB)
Note: All faults are latched. Bit(s) are cleared after reading register contents. If the fault is still present, the bit is set again.
Table 17. CHIP_ID1
This register contains the MAX8834Y/MAX8834Z die type number.
REGISTER NAME
Address
CHIP_ID1
0x1A
N/A
Reset Value
Type
Read
—
Special Features
BIT
B7 (MSB)
B6
NAME
DESCRIPTION
DEFAULT VALUE
DIE_TYPE[7:4]
BCD Character 1
[0001]
B5
B4
B3
B2
DIE_TYPE[3:0]
BCD Character 1
[0001]
B1
B0 (LSB)
Note: This register value is fixed in metal.
38
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Table 18. CHIP_ID2
This register contains the die type dash number (0 = plain) and mask revision level.
REGISTER NAME
Address
CHIP_ID2
0x1B
N/A
Reset Value
Type
Read
—
Special Features
BIT
B7 (MSB)
B6
NAME
DESCRIPTION
DEFAULT VALUE
DASH
BCD Character representing dash number
—
B5
B4
B3
B2
MASK_REV BCD Character representing die revision
—
B1
B0 (LSB)
Note: This register value is fixed in metal.
most situations, but a 4.7µF ceramic capacitor is
acceptable for lower load currents.
Applications Information
Inductor Selection
See Table 19 for a list of recommended inductors. To
prevent core saturation, ensure that the inductor satura-
tion current rating exceeds the peak inductor current
for the application. Calculate the worst-case peak
inductor current as follows:
Compensation Network Selection
The step-up converter is compensated for stability
through an external compensation network from COMP
to AGND. See Table 20 for recommended compensa-
tion networks.
PCB Layout
Due to fast-switching waveforms and high-current
paths, careful PCB layout is required. Connect AGND,
FGND, and PGND directly to the ground plane. The IN
bypass capacitor should be placed as close as possi-
V
×I
V
IN(MIN)
OUT OUT(MAX)
I
=
+
PEAK
0.9 × V
2 × f × L
SW
IN(MIN)
where f
is the switching frequency.
SW
ble to the IC. R
and C
should be connected
COMP
COMP
Capacitor Selection
between COMP and AGND as close as possible to the
IC. Minimize trace lengths between the IC and the
inductor, the input capacitor, and the output capacitor;
keep these traces short, direct, and wide. The ground
Bypass IN to AGND and PGND with a ceramic capaci-
tor. Ceramic capacitors with X5R and X7R dielectrics are
recommended for their low ESR and tighter tolerances
over wide temperature ranges. Place the capacitor as
close as possible to the IC. The recommended minimum
value for the input capacitor is 10µF; however, larger
value capacitors can be used to reduce input ripple at
the expense of size and higher cost.
connections of C and C
should be as close
OUT
IN
together as possible and connected to PGND. The
traces from the input to the inductor and from the out-
put capacitor to the LEDs may be longer. Figure 21
illustrates an example PCB layout and routing scheme.
Refer to the MAX8834Y/MAX8834Z Evaluation Kit for a
PCB layout example.
The output capacitance required depends on the out-
put current. A 10µF ceramic capacitor works well in
Maxim Integrated
39
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Table 19. Suggested Inductors
DIMENSIONS
x W x H
MANUFACTURER
PART/SERIES
INDUCTANCE (µH)
DCR (mꢀ) ISAT (A)
(l
TYP
)
MAX
TYP
(mm)
LPS4012-222ML
LPS4018-222ML
LPS5030-220ML
LPS6225-222ML
LPO3310-102ML
LPS3015-102ML
LPO3010-102NLC
DO3314-102ML
LPS3314-102ML
DP1605T-102ML
LPS4012-102ML
LPS4018-102ML
LPS5015-102ML
NR4018T2R2M
NR3012T1R0N
NR4010T1R0N
NR3015T1R0N
NR4012T1R0N
NP03SB1R0M
2.2
2.2
2.2
2.2
1
100
70
57
45
76
75
140
110
45
40
60
40
50
72
60
120
36
72
27
30
36
65
56
40
30
40
2.3
2.7
3.1
3.9
1.6
1.6
1.7
2.1
2.3
2.5
2.8
2.8
3.8
2.7
1.5
1.8
2.1
2.5
2.6
4
4 x 4 x 1.1
4 x 4 x 1.7
5 x 5 x 2.9
6.2 x 6.2 x 2.5
3 x 3 x 1
1
3 x 3 x 1
Coilcraft
1
3 x 3 x 1
1
3 x 3 x 1.4
3 x 3 x 1.4
4 x 4 x 1.8
4 x 4 x 1.1
4 x 4 x 1.7
5 x 5 x 1.5
4 x 4 x 1.8
3 x 3 x 1.2
4 x 4 x 1
1
1
1
1
1
2.2
1
1
1
3 x 3 x 1.5
4 x 4 x 1.2
4 x 4 x 1.8
5 x 5 x 2
Taiyo Yuden
1
1
NP04SZB1R0N
NR4018T1R0N
1117AS-1R2N
1
1
4
4 x 4 x 1.8
3 x 3 x 1
1.2
1.2
1
1.2
1.8
1.8
1.95
2.1
1098AS-1R2N
3 x 3 x 1.2
4 x 4 x 1.8
3 x 3 x 1.8
3 x 3 x 1.5
TOKO
A997AS-1R0N
1072AS-1R0N
1
1071AS-1R0N
1
Table 20. Suggested Compensation
Networks
R
(kꢀ)
C
COMP
(pF)
COMP
INDUCTANCE
1.0µH Inductor (dynamic loads)
2.2µH Inductor (dynamic loads)
4.7µH Inductor (dynamic loads)
10µH Inductor (dynamic loads)
Other (non-LED) Loads (1µH to 10µH)
5.5
4.3
3
2200
2200
4700
6800
22000
3
0 (short)
40
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
IN
L
5mm
C
OUT
C
IN
V
DD
IN
LX
A2
PGND
A3
OUT
V
DD
A1
A4
A5
PGND
B3
LX
B2
SCL
B4
AGND
B5
OUT
B1
GND
FGND
C2
GSMB
C4
SDA
C5
COMP
C1
LED_EN
C3
SCL
SDA
GSMB
FGND
D2
FLED2
D1
FLED1
D3
INDLED
D4
NTC
D5
NTC
LED_EN
3.8mm
Figure 21. Recommended PCB Layout
Maxim Integrated
41
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Block Diagram and Typical Application Circuit
PROGRAMMABLE
OUTPUT
3.7V TO 5.2V
1µH
LX
IN
OUT
C
OUT
INPUT
CURRENT
LIMIT
10µF
V
C
IN
UVLO AND
POWER
IN
PWM STEP-UP
CONVERTER
2.5V TO 5.5V
10µF
AGND
V
REF
ADAPTIVE/
FIXED
PGND
COMP
OUTPUT
SELECT
SELECT
MIN
V
REG
C
R
COMP
2MHz OR 4MHz
COMP
FLASH
TIMER
V
POK
750mA
FLED1
FLED2
WATCHDOG
TIMER
NTC
750mA
16mA
GSMB
REGISTERS
R
NTC
PA_EN
AND
CONTROL
LOGIC
100kΩ
1MHz
V
LOGIC
1.62V TO 3.6V
INDLED
FGND
LED_EN
FLASH/MOVIE
STROBE
SAMPLING
LOGIC
V
DD
C
VDD
0.1µF
2
I C
INTERFACE
MAX8834Y
MAX8834Z
SDA
SCL
2
I C
INTERFACE
42
Maxim Integrated
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Pin Configuration
Chip Information
PROCESS: BiCMOS
TOP VIEW
(BUMPS ON BOTTOM)
1
2
3
5
4
MAX8834Y/MAX8834Z
Package Information
A
A1
A2
LX
A3
A4
IN
A5
For the latest package outline information and land patterns (foot-
prints), go to www.maximintegrated.com/packages. Note that a
“+”, “#”, or “-” in the package code indicates RoHS status only.
Package drawings may show a different suffix character, but the
drawing pertains to the package regardless of RoHS status.
V
OUT
PGND
DD
B
B1
B2
LX
B3
B4
B5
AGND
OUT
PGND
SCL
PACKAGE TYPE PACKAGE CODE DOCUMENT NO.
20 WLP
W202A2+2
21-0059
C
D
C1
C2
C3
C4
C5
SDA
COMP
LED_EN
FGND
GSMB
D1
D2
D3
D4
D5
NTC
FLED2
FLED1
FGND
INDLED
WLP
(2.5mm ×× 2.0mm)
Maxim Integrated
43
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
Revision History
REVISION
NUMBER
REVISION
DATE
PAGES
CHANGED
DESCRIPTION
0
1
2
4/09
5/09
2/10
Initial release
—
38, 39, 41
28
Added notes to Tables 16 and 18, and updated Figure 21
Corrected register value in Table 5
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent
licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and
max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
44 ________________________________Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000
© 2010 Maxim Integrated Products, Inc.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
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