MAX1759EUB+T [MAXIM]
Switched Capacitor Regulator, Voltage-mode, 0.1A, 1800kHz Switching Freq-Max, PDSO10, MICRO MAX PACKAGE-10;
| 型号： | MAX1759EUB+T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Switched Capacitor Regulator, Voltage-mode, 0.1A, 1800kHz Switching Freq-Max, PDSO10, MICRO MAX PACKAGE-10 泵 |
| 文件： | 总12页 (文件大小：191K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-1600; Rev 0; 1/00
Buck/Boost Regulating
Charge Pump in µMAX
General Description
Features
The MAX1759 is a buck/boost regulating charge pump
that generates a regulated output voltage from a single
lithium-ion (Li+) cell, or two or three NiMH or alkaline
cells for small hand-held portable equipment. The
MAX1759 operates over a wide +1.6V to +5.5V input
voltage range and generates a fixed 3.3V or adjustable
ꢀ Regulated Output Voltage (Fixed 3.3V or
Adjustable 2.5V to 5.5V)
ꢀ 100mA Guaranteed Output Current
ꢀ +1.6V to +5.5V Input Voltage Range
ꢀ Low 50µA Quiescent Supply Current
ꢀ 1µA Shutdown Mode
™)
(2.5V to 5.5V) output (Dual Mode . Maxim’s unique
charge-pump architecture allows the input voltage to be
higher or lower than the regulated output voltage.
Despite its high 1.5MHz operating frequency, the
MAX1759 maintains low 50µA quiescent supply current.
ꢀ Load Disconnected from Input in Shutdown
ꢀ High 1.5MHz Operating Frequency
ꢀ Uses Small Ceramic Capacitors
ꢀ Short-Circuit Protection and Thermal Shutdown
ꢀ Small 10-Pin µMAX Package
Designed to be an extremely compact buck/boost con-
verter, this device requires only three small ceramic
capacitors to build a complete DC-DC converter capa-
ble of generating a guaranteed 100mA (min) output
current from a +2.5V input. For added flexibility, the
MAX1759 also includes an open-drain power-OK
(POK) output that signals when the output voltage is in
regulation.
The MAX1759 is available in a space-saving 10-pin
µMAX package that is 1.09mm high and half the size of
an 8-pin SO.
Ordering Information
Applications
PART
TEMP. RANGE
PIN-PACKAGE
Li+ Battery-Powered Applications
MAX1759EUB
-40°C to +85°C
10 µMAX
Miniature Equipment
Backup Battery Boost Converters
Translators
Typical Operating Circuit
Pin Configuration
TOP VIEW
C
X
IN
OUT
3.3V AT 100mA
CXN
CXP
OUT
+1.6V TO +5.5V
POK
SHDN
IN
1
2
3
4
5
10 FB
IN
9
8
7
6
OUT
C
C
OUT
IN
MAX1759
CXP
MAX1759
IN
CXN
PGND
ON
GND
POK
POWER OK
SHDN
OFF
FB GND PGND
µMAX
Dual Mode is a trademark of Maxim Integrated Products.
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
Buck/Boost Regulating
Charge Pump in µMAX
ABSOLUTE MAXIMUM RATINGS
IN, OUT, FB, POK, SHDN to GND............................-0.3V to +6V
PGND to GND..................................................................... 0.3V
CXN to GND ................................................-0.3V to (V + 0.3V)
Operating Temperature Range .......................... -40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s) ................................ +300°C
IN
OUT
CXP to GND..............................................-0.3V to (V
+ 0.3V)
OUT Short to GND.........................................................Indefinite
Continuous Power Dissipation (T = +70°C)
A
10-Pin µMAX (derate 5.6mW/°C above +70°C).........444mW
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
(Circuit of Figure 1, V = V
= 2V, FB = PGND = GND, C = 10µF, C = 0.33µF, C
= 10µF, T = 0°C to +85°C, unless oth-
OUT A
IN
SHDN
IN
X
erwise noted. Typical values are at T = +25°C.)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Input Voltage Range
V
IN
1.6
5.5
V
Input Undervoltage Lockout
Voltage
V
UVLO
0.6
1.0
1.4
V
Output Voltage Adjustment Range
1.6V ≤ V ≤ 5.5V
2.5
3.17
3.17
100
5.5
V
V
IN
2V ≤ V ≤ 5.5V, 1mA ≤ I
≤ 50mA
3.3
3.3
3.43
3.43
IN
LOAD
Output Voltage
V
OUT
2.5V ≤ V ≤ 5.5V, 1mA ≤ I
≤ 100mA
IN
LOAD
Maximum Output Current
Transient Load Current
I
2.5V ≤ V ≤ 5.5V
mA
mA
LOAD,MAX
IN
I
≤ 100mA (RMS)
200
50
85
1
LOAD
V
IN
V
IN
= V
= V
= 4V, V = 0, stepping down
90
180
5
FB
SHDN
SHDN
Quiescent Supply Current
Shutdown Supply Current
I
Q
µA
µA
µA
= 2V, V = 0, stepping up
FB
I
1.6V ≤ V ≤ 5.5V, V = 0
SHDN
Q,SHDN
IN
Leakage Current into OUT in
Shutdown
V
IN
= 2V, V
= 3.3V, V
= 0
1
5
OUT
SHDN
V
1.6V ≤ V ≤ 5.5V
0.25 · V
IL
IN
IN
V
SHDN Logic Input Voltage
V
IH
1.6V ≤ V ≤ 5.5V
0.7 · V
IN
IN
I
V
V
V
= 5.5V
SHDN
-1
1
µA
V
SHDN Input Leakage Current
FB Regulation Voltage
FB Input Current
SHDN
V
FB
= 1.65V, V = 3.3V
OUT
1.205
1.235
25
1.265
200
50
IN
= 1.27V
nA
mV
mV
V
FB
Internal feedback
External feedback
Falling edge at FB
100
100
1.1
5
FB Dual-Mode Threshold
200
1.0
POK Trip Voltage
1.2
100
0.2
1.8
POK Output Low Voltage
POK Leakage Current
Switching Frequency
Output Short-Circuit Current
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
Efficiency
V
OL
I
= 0.5mA, V = 2V
mV
µA
MHz
mA
°C
SINK
IN
V
POK
= 5.5V, V = 1.27V
0.01
1.5
110
160
20
FB
f
1.6V ≤ V ≤ 5.5V, V = 1V
1.2
OSC
IN
FB
V
OUT
= 0, 2.5V ≤ V ≤5.5V, foldback current limit
IN
Rising temperature
°C
V
IN
= 3.6V, I = 10mA
90
%
LOAD
2
_______________________________________________________________________________________
Buck/Boost Regulating
Charge Pump in µMAX
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, V = V
= 2V, FB = PGND = GND, C = 10µF, C = 0.33µF, C
= 10µF, T = -40°C to +85°C, unless oth-
OUT A
IN
SHDN
IN
X
erwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
MAX
UNITS
Input Voltage Range
V
IN
1.6
5.5
V
Input Undervoltage Lockout
Voltage
V
UVLO
0.6
1.4
V
2V ≤ V ≤ 5.5V, 0 ≤ I
≤ 50mA
3.15
3.15
3.45
3.45
V
V
IN
LOAD
Output Voltage
V
OUT
2.5V ≤ V ≤ 5.5V, 0 ≤ I
≤ 100mA
IN
LOAD
Output Voltage Adjustment
Range
1.6V ≤ V ≤ 5.5V
2.5
5.5
V
IN
Maximum Output Current
Quiescent Supply Current
Shutdown Supply Current
I
2.5V ≤ V ≤ 5.5V
100
mA
µA
µA
µA
LOAD,MAX
IN
V
= V
= V
= 4V, V = 0
90
180
6
IN
IN
SHDN
SHDN
FB
I
Q
V
= 2.5V, V = 0
FB
I
1.6V ≤ V ≤ 5.5V, V = 0
SHDN
Q,SHDN
IN
Leakage Current into OUT in
Shutdown
V
IN
= 2V, V
= 3.3V, V
= 0
5
OUT
SHDN
V
1.6V ≤ V ≤ 5.5V
V
V
0.2 · V
IL
IN
IN
SHDN Input Logic Voltage
V
IH
1.6V ≤ V ≤ 5.5V
0.7 · V
IN
IN
I
V
V
V
= 5.5V
SHDN
-1
1
µA
V
SHDN Input Leakage Current
FB Regulation Voltage
FB Input Bias Current
SHDN
V
FB
= 1.65V, V = 3.3V
OUT
1.205
1.265
200
40
IN
= 1.27V
nA
mV
mV
V
FB
Internal feedback
External feedback
Falling edge at FB
FB Dual Mode Threshold
200
1.0
POK Trip Voltage
1.2
100
0.2
1.9
POK Output Low Voltage
POK Leakage Current
Switching Frequency
V
OL
I
= 0.5mA, V = 2V
IN
mV
µA
MHz
SINK
V
POK
= 5.5V
f
1.6V ≤ V ≤ 5.5V, V = 1V
1.1
OSC
IN
FB
Note 1: Specifications to -40°C are guaranteed by design and are not production tested.
_______________________________________________________________________________________
3
Buck/Boost Regulating
Charge Pump in µMAX
Typical Operating Characteristics
(Circuit of Figure 1, C = 10µF, C = 0.33µF, C
= 10µF, V
= 3.3V, V = 2.5V, T = +25°C, unless otherwise noted.)
IN
X
OUT
OUT IN A
OUTPUT VOLTAGE RIPPLE
vs. INPUT VOLTAGE
EFFICIENCY vs. INPUT VOLTAGE
OUTPUT VOLTAGE vs. LOAD CURRENT
100
90
80
70
60
50
40
30
20
10
0
3.40
3.35
100
80
60
40
20
0
I
= 10mA
OUT
I
= 100mA
= 50mA
OUT
I
= 50mA
OUT
I
OUT
3.30
3.25
3.20
I
= 100mA
OUT
I
= 10mA
OUT
1.5
2.5
3.5
INPUT VOLTAGE (V)
4.5
5.5
0.001 0.01
0.1
1
10
100 1000
1.5
2.5
3.5
INPUT VOLTAGE (V)
4.5
5.5
LOAD CURRENT (mA)
QUIESCENT CURRENT
vs. INPUT VOLTAGE
TYPICAL SWITCHING WAVEFORMS
(V < V )
STARTUP INPUT VOLTAGE
(V
OUT
< V )
IN
OUT
IN
10,000
1000
100
4
3
2
1
0
R
V
= 33Ω
LOAD
R
= 33Ω
LOAD
= 4.2V
IN
1
2
10
1
3
NO LOAD
4.5 5.5
0.5
1.5
2.5
3.5
5µs/div
CH1: V , 20mV/div, AC-COUPLED
0.5
1.5
2.5
3.5
4.5
5.5
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
OUT
CH2: V , 5V/div
CXP
CH3: V , 50mV/div, AC-COUPLED
IN
TYPICAL SWITCHING WAVEFORMS
(V > V )
LOAD-TRANSIENT RESPONSE
(V < V )
LOAD-TRANSIENT RESPONSE
(V
> V )
OUT
IN
OUT
IN
OUT
IN
R
V
= 33Ω
LOAD
= 2.5V
IN
1
1
2
1
2
2
3
LOAD STEP: 10mA TO 100mA
= 4.2V
LOAD STEP: 10mA TO 100mA
= 2.5V
V
V
IN
IN
5µs/div
100µs/div
100µs/div
CH1: V , 20mV/div, AC-COUPLED
OUT
CH1: V , 20mV/div, AC-COUPLED
OUT
CH1: V , 20mV/div, AC-COUPLED
OUT
CH2: V , 5V/div
CH2: I , 100mA/div
CH2: I , 100mA/div
CXP
OUT
OUT
CH3: V , 50mV/div, AC-COUPLED
IN
4
_______________________________________________________________________________________
Buck/Boost Regulating
Charge Pump in µMAX
Typical Operating Characteristics (continued)
(Circuit of Figure 1, C = 10µF, C = 0.33µF, C
= 10µF, V
= 3.3V, V = 2.5V, T = +25°C, unless otherwise noted.)
IN
X
OUT
OUT IN A
TURN-ON/OFF RESPONSE
TURN-ON/OFF RESPONSE
(V = 4.2V)
IN
LINE-TRANSIENT RESPONSE
(V = 2.5V)
IN
R
IN
= 33Ω
R
= 33Ω
LOAD
= 4.2V
R
V
= 33Ω
LOAD
LOAD
V
= 2.5V
IN
1
2
1
2
1
2
-4.2V
-2.5V
3
4
3
4
100µs/div
500µs/div
500µs/div
CH1: V ,1V/div
CH1: V , 20mV/div, AC-COUPLED
OUT
OUT
CH1: V ,1V/div
OUT
CH2: I , 200mA/div
CH2: V , 1V/div, AC-COUPLED
IN
IN
CH2: I , 200mA/div
IN
CH3: V , 5V/div
POK
SHDN
CH3: V , 5V/div
POK
SHDN
CH4: V
, 5V/div
CH4: V
, 5V/div
Pin Description
PIN
NAME
FUNCTION
Open-Drain Power-OK Output. POK is high impedance when output voltage is in regulation. POK sinks current
when V falls below 1.1V. Connect a 10kΩ to 1MΩ pull-up resistor from POK to V for a logic signal.
1
POK
FB
OUT
Ground POK or leave unconnected if not used. POK is high impedance in shutdown.
Shutdown Input. Drive high for normal operation; drive low for shutdown mode. OUT is high impedance in
shutdown.
2
SHDN
Input Supply. Connect both pins together and bypass to GND with a ceramic capacitor (see Capacitor
Selection section).
3, 4
IN
5
6
7
8
9
GND
PGND
CXN
Ground. Connect GND to PGND with a short trace.
Power Ground. Charge-pump current flows through this pin.
Negative Terminal of the Charge-Pump Transfer Capacitor
Positive Terminal of the Charge-Pump Transfer Capacitor
Power Output. Bypass to GND with an output filter capacitor.
CXP
OUT
Dual-Mode Feedback. Connect FB to GND for 3.3V output. Connect to an external resistor divider to adjust
the output voltage from 2.5V to 5.5V.
10
FB
_______________________________________________________________________________________
5
Buck/Boost Regulating
Charge Pump in µMAX
Detailed Description
0.33µF
The MAX1759’s unique charge-pump architecture
allows the input voltage to be higher or lower than the
IN
OUT
CXN
CXP
OUT
+1.6V TO +5.5V
3.3V AT 100mA
regulated output voltage. Internal circuitry senses V
IN
IN
and V
and determines whether V
must be
OUT
IN
stepped up or stepped down to produce the regulated
output. When V is lower than V , the charge pump
10µF
10µF
100k
IN
OUT
MAX1759
operates as a regulated step-up voltage doubler. When
V
is higher than V
, the charge pump operates as
ON
IN
OUT
POK
a step-down gated switch.
POWER OK
SHDN
OFF
FB GND PGND
In voltage step-down mode (i.e., the input voltage is
greater than the output voltage) with a light load, the
controller connects CXN to PGND, and shuttles charge
to the output by alternately connecting CXP from IN to
Figure 1. Typical Application Circuit
OUT (see Figures 1 and 2). Although V is greater than
IN
V
, this scheme may not allow the MAX1759 to regu-
OUT
late the output under heavy loads. In this case, the
MAX1759 will automatically switch to step-up mode. In
step-up mode, the output is kept in regulation by modu-
lating the charge delivered by the transfer capacitor
Thermal Shutdown
The MAX1759 features thermal shutdown with tempera-
ture hysteresis. When the die temperature exceeds
160°C, the device shuts down. When the die cools by
20°C, the MAX1759 turns on again. If high die tempera-
ture is caused by output overload and the load is not
removed, the device will turn off and on, resulting in a
pulsed output.
(C ) to the load (see Figure 2). When lightly loaded, the
X
charge pump switches only as necessary to supply the
load, resulting in low quiescent current. Output voltage
ripple does not increase with light loads.
Shutdown Mode
Driving SHDN low places the MAX1759 in shutdown
mode. This disables the charge-pump switches, oscil-
lator, and control logic, reducing quiescent current to
1µA. The output is high impedance in shutdown and is
disconnected from the input. The POK output is high
impedance in shutdown.
Design Procedure
Setting the Output Voltage
The MAX1759 dual-mode feedback controller selects
between the internally set 3.3V regulated output or an
external resistive divider that allows adjustment of the
output voltage from 2.5V to 5.5V. Connect FB to GND
for a regulated 3.3V output. For an adjustable output,
connect a resistive divider between OUT and GND. To
ensure feedback-loop stability and to minimize error due
to FB pin bias currents, the resistive divider current
should be approximately 15µA. In the following equa-
tion, choose R2 in the 50kΩ to 100kΩ range, and calcu-
late R1 from the following formula (Figure 3):
Undervoltage Lockout
The MAX1759 undervoltage lockout feature deactivates
the device when the input voltage falls below 1V.
Power-OK Output
POK is an open-drain output that sinks current when
the regulator feedback voltage falls below 1.1V. The
feedback voltage can be either the internal resistor-
divider feedback voltage when in fixed output mode
(FB tied to GND) or an external feedback voltage from
an external resistive divider in adjustable output mode.
A 10kΩ to 1MΩ pull-up resistor from POK to OUT may
be used to provide a logic output. Connect POK to GND
or leave unconnected if not used.
R1 = R2 [(V
/ V ) - 1]
FB
OUT
and
V
OUT
= V (R1 + R2) / R2
FB
where V
is the desired output voltage from 2.5V to
5.5V, and V is the internal regulation voltage, nomi-
OUT
FB
nally 1.235V.
The circuit of Figure 3 generates a regulated 2.5V, using
external standard 1% resistor values. Surface-mount
resistors should be placed close to the MAX1759, less
than 5mm away from FB (see the PC Board Layout
section).
Soft-Start and Short-Circuit Protection
The MAX1759 features foldback short-circuit protec-
tion. This circuitry provides soft-start by limiting inrush
current during startup and limits the output current to
110mA (typ) if the output is short-circuited to ground.
6
_______________________________________________________________________________________
Buck/Boost Regulating
Charge Pump in µMAX
CXN 7
CXP 8
IN
3, 4
PGND
6
OUT
9
S1
S2
R1
MAX1759
BUCK-BOOST
CONTROL
R2
ENABLE
SHDN
2
1.5MHz
OSC
BIAS
FB
10
1.235V
POK
1
OUT-LOW
N
1.1V
0.1V
GND
5
Figure 2. Functional Diagram
_______________________________________________________________________________________
7
Buck/Boost Regulating
Charge Pump in µMAX
Capacitor Selection
Optimize the charge-pump circuit for physical size, out-
put current, and output ripple by selecting capacitors
0.33µF
C , C , and C . See Table 1 for suggested capacitor
OUT
IN
X
CXN
CXP
OUT
V
= 2.5V
OUT
values.
Note that capacitors must have low ESR (≤20mΩ) to
maintain low output ripple. Ceramic capacitors are
recommended. In cost-sensitive applications where high
output current is needed, the output capacitor may be a
combination of a 1µF ceramic in parallel with a 10µF tan-
talum capacitor. The ceramic capacitor’s low ESR will
help keep output ripple within acceptable levels.
V
= 1.6V TO 5.5V
IN
10µF
IN
100k
10µF
MAX1759
POK
FB
R1
SHDN
76.8k
Output Voltage Ripple
The MAX1759 proprietary control scheme automatically
chooses between voltage doubling and voltage step-
down to maintain output voltage regulation over various
GND
PGND
R2
75k
load currents and V to V
voltage differentials.
OUT
IN
When V is lower than V
, the charge pump always
IN
OUT
Figure 3. Using External Feedback for Regulated 2.5V Output
operates in voltage-doubler mode. It regulates the output
voltage by modulating the charge delivered by the
transfer capacitor.
Table 1. Capacitor Selection
When V is higher than V
, the charge pump oper-
IN
OUT
ates in voltage step-down mode, but may revert to volt-
age-doubler mode if necessary to maintain regulation
under load. While operating in step-down mode, the
output voltage ripple is typically much lower than it is in
voltage-doubler mode (see Typical Operating
Characteristics).
OUTPUT RIPPLE
CAPACITOR VALUE
OUTPUT
CURRENT
(mA)
(mV)
C
IN
C
X
C
OUT
V
=
V
=
IN
IN
(µF)
(µF)
(µF)
2.5V
4.2V
100
100
50
10
4.7
2.2
0.33
0.22
0.1
10
4.7
2.2
40
80
20
60
80
Output Current
The MAX1759 is guaranteed to deliver a regulated 3.3V
at 100mA continuous, from a +2.5V input. Peaks up to
200mA are acceptable as long as the current is
≤100mA (RMS).
100
Applications Information
PC Board Layout
The MAX1759 is a high-frequency switched-capacitor
voltage regulator. For best circuit performance, use a
ground plane and keep C , C , C , and feedback
OUT
IN
X
resistors (if used) close to the device. If using external
feedback, keep the feedback node as small as possi-
ble by positioning the feedback resistors very close to
FB. Suggested PC component placement and board
layout are shown in Figures 4a and 4b.
Chip Information
TRANSISTOR COUNT: 1802
8
_______________________________________________________________________________________
Buck/Boost Regulating
Charge Pump in µMAX
POK
POK
SHDN
SHDN
R3 R2
R1
C3
V
OUT
V
OUT
V
V
IN
IN
U1
C2
C1
GND PLANE
GND PLANE
Figure 4a. MAX1759 Component Placement Guide
Figure 4b. MAX1759 Recommended PC Board Layout
_______________________________________________________________________________________
9
Buck/Boost Regulating
Charge Pump in µMAX
Package Information
Note: The MAX1759 does not have an exposed pad.
10 ______________________________________________________________________________________
Buck/Boost Regulating
Charge Pump in µMAX
NOTES
______________________________________________________________________________________ 11
Buck/Boost Regulating
Charge Pump in µMAX
NOTES
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2000 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
相关型号：
MAX1759EUB-T
Switched Capacitor Regulator, Voltage-mode, 0.1A, 1800kHz Switching Freq-Max, PDSO10, MICRO MAX PACKAGE-10
MAXIM
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