MAX884 [MAXIM]
5V/3.3V or Adjustable, Low-Dropout, Low IQ, 200mA Linear Regulators; 5V / 3.3V或可调,低压差,低IQ , 200mA线性稳压器型号: | MAX884 |
厂家: | MAXIM INTEGRATED PRODUCTS |
描述: | 5V/3.3V or Adjustable, Low-Dropout, Low IQ, 200mA Linear Regulators |
文件: | 总16页 (文件大小:137K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
19-0275; Rev 0; 12/94
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23/MAX84
_______________Ge n e ra l De s c rip t io n
____________________________Fe a t u re s
The MAX882/MAX883/MAX884 linear regulators maxi-
mize battery life by combining ultra-low supply currents
and low dropout voltages. They feature 200mA output
current capability at up to +125°C junction temperature
and come in a 1.5W SOIC package. The 1.5W package
(c omp a re d to 0.47W for s ta nd a rd SOIC p a c ka g e s )
allows a wider operating range for the input voltage and
output current. The MAX882/MAX883/MAX884 use a P-
channel MOSFET pass transistor to maintain a low 11µA
(15µA ma x) s up p ly c urre nt from no-loa d to the full
200mA output. Unlike earlier bipolar regulators, there are
no PNP base current losses that increase with output
current. And, in dropout, the MOSFET does not suffer
from excessive base currents that occur when PNP tran-
sistors go into saturation. Typical dropout voltages are
220mV at 5V and 200mA, or 320mV at 3.3V and 200mA.
♦ Guaranteed 200mA Output Current at
T = +125°C, with Foldback Current Limiting
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♦ High-Power (1.5W) 8-Pin SO Package
♦ Dual Mode™ Operation: Fixed or Adjustable
Output from 1.25V to 11V
♦ Large Input Range (2.7V to 11.5V)
♦ Internal 1.1Ω P-Channel Pass Transistor
Draws No Base Current
♦ Low 220mV Dropout Voltage at 200mA
Output Current
♦ 11µA Typical Quiescent Current
♦ 1µA (max) Shutdown Mode or 7µA (typ)
The MAX882 features a 7µA standby mode that disables
the output but keeps the reference, low-battery compara-
tor, and biasing circuitry alive. The MAX883/MAX884 fea-
ture a shutdown (OFF) mode that turns off all circuitry,
re d uc ing s up p ly c urre nt to le s s tha n 1µA. All thre e
devices include a low-battery-detection comparator, fold-
back current limiting, reverse-current protection, and
thermal overload protection.
Standby Mode
♦ Low-Battery Detection Comparator
♦ Reverse-Current Protection
♦ Thermal Overload Protection
______________Ord e rin g In fo rm a t io n
The output is preset at 3.3V for the MAX882/MAX884
and 5V for the MAX883. In addition, all devices employ
Dual Mode™ operation, allowing user-adjustable outputs
from 1.25V to 11V using external resistors. The input volt-
age supply range is 2.7V to 11.5V.
PART
TEMP. RANGE
0°C to +70°C
PIN-PACKAGE
8 Plastic DIP
8 SO
MAX882CPA
MAX882CSA
MAX882C/D
MAX882EPA
MAX882ESA
MAX882MJA
0°C to +70°C
0°C to +70°C
Dice*
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
8 Plastic DIP
8 SO
For low-dropout linear regulators with output currents up
to 500mA, refer to the MAX603/MAX604 data sheet.
8 CERDIP**
________________________Ap p lic a t io n s
Ordering Information continued at end of data sheet.
* Dice are tested at T = +25°C, DC parameters only.
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** Contact factory for availability.
Pagers and Cellular Phones
3.3V and 5V Regulators
1.25V to 11V Adjustable Regulators
High-Efficiency Linear Regulators
Battery-Powered Devices
Portable Instruments
__________Typ ic a l Op e ra t in g Circ u it
ON/OFF
OFF (STBY)
Solar-Powered Instruments
__________________P in Co n fig u ra t io n
OUTPUT
VOLTAGE
MAX882
MAX883
MAX884
IN
OUT
TOP VIEW
INPUT
VOLTAGE
LBI
1
2
3
4
8
7
6
5
LBI
LBO
SET
C
C
OUT
IN
O.1µF
2.2µF
OFF (STBY)
SET
GND
MAX882
MAX883
MAX884
BATTERY
GND
OUT
GND
IN
( ) ARE FOR MAX882
( ) ARE FOR MAX882
DIP/SO
™Dual-Mode is a trademark of Maxim Integrated Products.
________________________________________________________________ Maxim Integrated Products
1
Ca ll t o ll fre e 1 -8 0 0 -9 9 8 -8 8 0 0 fo r fre e s a m p le s o r lit e ra t u re .
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ABSOLUTE MAXIMUM RATINGS
Supply Voltage (IN or OUT to GND).......................-0.3V to +12V
Output Short-Circuit Duration .........................................1 minute
Continuous Output Current...............................................300mA
LBO Output Current............................................................50mA
LBO Output Voltage and LBI,
High-Power SO (derate 18.75mW/°C above +70°C) .......1.5W
CERDIP (derate 8.00mW/°C above +70°C).................640mW
Operating Temperature Ranges
MAX88_C_A........................................................0°C to +70°C
MAX88_E_A .....................................................-40°C to +85°C
MAX88_MJA ..................................................-55°C to +125°C
Junction Temperature .....................................................+150°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
SET, STBY, OFF Input Voltages ................-0.3V to the greater of
(IN + 0.3V) or (OUT + 0.3V)
Continuous Power Dissipation (T = +70°C)
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Plastic DIP (derate 9.09mW/°C above +70°C) ............727mW
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 = 6V (MAX883) or V = 4.3V (MAX882/MAX884), C
= 2.2µF, STBY or OFF = V , SET = GND, LBI = V , T = T
to T
,
IN
IN
OUT
IN
IN
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MIN
MAX
unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
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PARAMETER
SYMBOL
CONDITIONS
MAX88_C_A
MIN
2.7
2.9
3.0
TYP
MAX
UNITS
11.5
11.5
11.5
Input Voltage Range
V
IN
SET = OUT, R = 1kΩ MAX88_E_A
V
L
MAX88_MJA
I
= 10µA–200mA,
OUT
T
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≤ +125°C
23/MAX84
MAX883,
I
= 10µA–250mA,
OUT
4.75
5.00
5.25
6.0V ≤ V ≤ 11.5V
T ≤ +85°C
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IN
mV
I
T
= 10µA–250mA,
≤ +70°C
OUT
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Output Voltage (Note 2)
V
OUT
I
= 10µA–150mA,
OUT
T
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≤ +125°C
MAX882/MAX884,
I
= 10µA–200mA,
OUT
3.15
3.30
3.45
4.3V ≤ V ≤ 11.5V
T ≤ +85°C
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IN
I
= 10µA–200mA,
OUT
T
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≤ +70°C
MAX883C_A/E_A
MAX883MJA
60
30
100
150
I
= 1mA to 200mA
OUT
Load Regulation
∆V
mV
mV
mV
LDR
I
= 1mA to 150mA MAX882, MAX884
100
OUT
Line Regulation
∆V
LNR
(V
+ 0.5V) < V < 11.5V, I = 10mA
OUT
10
40
220
440
320
640
15
OUT
IN
I
= 100mA
= 200mA
= 100mA
= 200mA
110
220
160
320
11
OUT
MAX883
I
OUT
Dropout Voltage (Note 3)
∆V
DO
I
OUT
MAX882/MAX884
SET = OUT,
I
OUT
MAX88_C_A/E_A
MAX88_MJA
V
= 6V
IN
30
Quiescent Current
I
Q
µA
MAX88_C_A/E_A
MAX88_MJA
15
25
V
= 11.5V
IN
40
2
_______________________________________________________________________________________
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23/MAX84
ELECTRICAL CHARACTERISTICS (continued)
(V = 6V (MAX883) or V = 4.3V (MAX882/MAX884), C
= 2.2µF, STBY or OFF = V , SET = GND, LBI = V , T = T
to T
,
IN
IN
OUT
IN
IN
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MIN
MAX
unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
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PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX882C_A/E_A
MAX882MJA
7
15
30
25
40
1
STBY = 0V,
= 6V, SET = OUT
V
IN
STBY Quiescent Current
(Note 4)
I
µA
Q STBY
MAX882C_A/E_A
MAX882MJA
10
STBY = 0V,
=11.5V, SET = OUT
V
IN
OFF = 0V,
= 1kΩ,
MAX88_C_A
0.01
R
L
OFF Quiescent Current
I
MAX88_E_A
5
µA
Q OFF
V
IN
= 11.5V
(MAX883/MAX884)
MAX88_MJA
MAX88_C_A
MAX88_E_A
MAX88_MJA
10
1
V
IN
= 11.5V,
Minimum Load Current
I
3
µA
OUT(MIN)
SET = OUT
10
V
< 0.8V
170
430
160
10
OUT
Foldback Current Limit (Note 5)
I
mA
LIM
V
OUT
> 0.8V and V - V > 0.7V
OUT
IN
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
T
°C
°C
SD
∆T
SD
V
= 4.5V
= 3.0V
MAX883_A
6
20
20
OUT
Reverse-Current-Protection
Threshold (Note 6)
∆V
mV
RTH
MAX882_A,
MAX884_A
V
OUT
6
7
MAX882:
= 0V, STBY = 0V, V
V
= 3.0V
OUT
IN
Reverse Leakage Current
Startup Overshoot
I
µA
RVL
MAX883/MAX884:
= 0V, OFF = 0V, V
0.01
1
V
= 3.0V
OUT
IN
% of
V
OUT
V
OSH
R
= 1kΩ, C
= 2.2µF
OUT
L
Time Required to Exit OFF or
STBY Modes
V
= 9V, R = 33Ω, OFF from 0V to V ,
IN L IN
T
200
µs
START
0% to 95% of V
OUT
For internal feedback
For external feedback
65
65
30
Dual Mode™ SET Threshold
V
SET TH
mV
150
SET Reference Voltage
SET Input Leakage Current
LBI Threshold Voltage
LBI Hysteresis
V
SET = OUT, R = 1kΩ
1.16
1.20
±0.01
1.20
7
1.24
±50
1.25
V
nA
V
SET
L
I
V
SET
= 1.5V or 0V
SET
V
LBI signal falling
1.15
LBI
∆V
mV
nA
LBI
LBI Input Leakage Current
I
V
LBI
= 1.5V
±0.01
±50
250
LBI
I
= 1.2mA, V =1V,
LBI
LBO SINK
LBO Output Low Voltage
V
LBOL
90
mV
µA
3V < V < 11.5V, SET = OUT
IN
LBO Output Leakage Current
I
V
LBI
= V , V
= V
IN
0.01
0.01
0.1
LBO LKG
IN LBO
MAX88_C_A
MAX88_E_A
MAX88_MJA
1
3
V
IN
= 11.5V,
OUT Leakage Current
I
V
OUT
= 2V,
µA
OUT LKG
SET = OUT
10
_______________________________________________________________________________________
3
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ELECTRICAL CHARACTERISTICS (continued)
(V = 6V (MAX883) or V = 4.3V (MAX882/MAX884), C
= 2.2µF, STBY or OFF = V , SET = GND, LBI = V , T = T
to T
,
IN
IN
OUT
IN
IN
J
MIN
MAX
unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
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PARAMETER
STBY Threshold Voltage
STBY Hysteresis
SYMBOL
CONDITIONS
STBY signal falling MAX882_A
MIN
TYP
MAX
UNITS
V
V
1.15
1.20
7
1.25
STBY
MAX882_A
MAX882_A
∆V
mV
nA
STBY
STBY Input Leakage Current
I
V
= V or 0V
±0.01
±50
0.4
STBY
STBY
IN
MAX883_A,
MAX884_A
V
IL OFF
In off mode
In on mode,
SET = OUT, V < 6V MAX884_A
IN
MAX883_A,
OFF Threshold Voltage
2.0
3.0
V
V
IH OFF
In on mode, SET = OUT, MAX883_A,
6V < V < 11.5V
MAX884_A
IN
OFF Input Leakage Current
Output Noise (Note 7)
I
V
= V or 0V
±0.01
250
±50
nA
OFF
OFF
IN
10Hz to 10kHz, SET = OUT, R = 1kΩ,
L
e
µV
RMS
n
C
= 2.2µF
OUT
Note 1: Electrical specifications are measured by pulse testing and are guaranteed for a junction temperature (T ) within the
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operating temperature range, unless otherwise noted. When operating C and E grade parts up to a T of +125°C, expect
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performance similar to M grade specifications. For T between +125°C and +150°C, the output voltage may drift more.
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Note 2: (V - V
) is limited to keep the product (I
x (V - V
)) from exceeding the package power dissipation limits. See
OUT
IN
OUT
OUT
IN
Figure 5. Therefore, the combination of high output current and high supply voltage is not tested. Output current at
= +125°C is guaranteed by guard banding tests at T = +85°C and +70°C.
23/MAX84
T
J
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Note 3: Dropout Voltage is (V - V
) when V
falls to 100mV below its nominal value at V = (V
+ 2V). For example, the
IN
OUT
OUT
IN
OUT
MAX883 is tested by measuring the V
at V = 7V, then V is lowered until V
falls 100mV below the measured
OUT
IN
IN
OUT
value. The difference (V - V
) is then measured and defined as ∆V
.
IN
OUT
DO
Note 4: Since standby mode inhibits the output but keeps all biasing circuitry alive, the Standby Quiescent Current is similar to the
normal operating quiescent current.
Note 5: Foldback Current Limit was characterized by pulse testing to remain below the maximum junction temperature (not
production tested).
Note 6: The Reverse-Current Protection Threshold is the output/input differential voltage (V
- V ) at which reverse-current
IN
OUT
protection switchover occurs and the pass transistor is turned off. See the section Reverse Current Protection in the
Detailed Description.
Note 7: Noise is tested using a bandpass amplifier with two poles at 10Hz and two poles at 10kHz.
4
_______________________________________________________________________________________
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23/MAX84
__________________________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s
(V = 7V for MAX883, VIN = 5.3V for MAX882/MAX884, OFF or STBY = VIN, SET = GND, LBI = V , LBO = OPEN, C = C
= 2.2µF,
IN
IN
IN
OUT
R
L
= 1kΩ, T = +25°C, unless otherwise noted.)
A
OUTPUT VOLTAGE
vs. TEMPERATURE
OUTPUT VOLTAGE AND QUIESCENT
CURRENT vs. LOAD CURRENT
104
103
102
101
100
99
101
100
99
30
25
20
15
10
V
OUT
= 5V (MAX883)
OUT
V
= 3.3V (MAX882/MAX884)
98
97
96
95
I
Q
98
OUTPUT VOLTAGE
NORMALIZED TO OUTPUT
VOLTAGE AT 1mA
5
0
97
96
-55 -35 -15
5
25 45 65 85 105 125
0.01
0.1
1
10
100 250
TEMPERATURE (°C)
LOAD CURRENT (mA)
QUIESCENT CURRENT
vs. TEMPERATURE
OUTPUT VOLTAGE AND QUIESCENT
CURRENT vs. SUPPLY VOLTAGE
15
12
6
5
4
3
2
16
14
12
10
8
V
= 5V (MAX883)
OUT
9
6
3
0
V
= 3.3V (MAX882/MAX884)
OUT
I
(MAX882/MAX884)
Q
6
I
Q
(MAX883)
0
4
-55 -35 -15
5
25 45 65 85 105 125
2
3
4
5
6
7
8
9
10 11 12
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
DROPOUT VOLTAGE
vs. LOAD CURRENT
10Hz to 10kHz OUTPUT NOISE
0.6
0.5
0.4
0.3
0.2
0.1
0
V
OUT
= 3.3V (MAX882/MAX884)
V
OUT
= 5V (MAX883)
MAX883
= 5V
V
OUT
10ms/div
0
50
100
150
200
250 300
LOAD CURRENT (mA)
_______________________________________________________________________________________
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____________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s (c o n t in u e d )
(V = 7V for MAX883, V = 5.3V for MAX882/MAX884, OFF or STBY = V , SET = GND, LBI = V , LBO = OPEN, C = C = 2.2µF,
OUT
IN
IN
IN
IN
IN
R
L
= 1kΩ, T = +25°C, unless otherwise noted.)
A
LINE-TRANSIENT RESPONSE
LOAD-TRANSIENT RESPONSE
A
A
B
B
500µs/div
1ms/div
MAX883: V
OUT
= 5V, C = 0µF, t = 15µs, t = 13µs
IN
MAX883: V
OUT
= 5V, t = 24µs, t = 44µs
R F
R
F
A: V = 8V (HIGH) / V = 7V (LOW)
B: OUTPUT VOLTAGE (100mV/div)
A: OUTPUT VOLTAGE (100mV/div)
B: I = 250mA (HIGH) / I = 50mA (LOW)
IN IN
OUT OUT
LBO LOW VOLTAGE
vs. SINK CURRENT
OVERSHOOT AND TIME
EXITING SHUTDOWN MODE
23/MAX84
5
4
3
2
1
0
R
L
= 100Ω
5V
B
A
MAX882/MAX884
MAX883
0V
500µs/div
0.1
1
10
50
A: OFF PIN VOLTAGE (1V/div):
RISE TIME = 9µs
SINK CURRENT (mA)
B: MAX883 OUTPUT VOLTAGE (1V/div):
DELAY = 135µs, RISE TIME = 67µs,
OVERSHOOT = 0%
6
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23/MAX84
______________________________________________________________P in De s c rip t io n
PIN
NAME
FUNCTION
MAX883/
MAX884
MAX882
Low-Battery Output is an open-drain output that goes low when LBI is less than 1.2V. Connect to
IN or OUT through a pull-up resistor. LBO is undefined during shutdown mode
(MAX883/MAX884).
1
2
1
2
LBO
SET
Feedback for setting the output voltage. Connect to GND to set the output voltage to the prese-
lected 3.3V or 5V. Connect to an external resistor network for adjustable-output operation.
Ground pins—also function as heatsinks in the SO package. All GND pins must be soldered to
the circuit board for proper power dissipation. Connect to large copper pads or planes to
channel heat from the IC.
3, 6
3, 6
GND
Regulator Output. Fixed or adjustable from 1.25V to 11.0V. Sources up to 200mA. Bypass with a
2.2µF capacitor.
4
5
7
4
5
OUT
IN
Regulator Input. Supply voltage can range from 2.7V to 11.5V.
Standby. Active-low comparator input. Connect to GND to disable the output or to IN for normal
operation. A resistor network (from IN) can be used to set a standby mode threshold.
—
STBY
Shutdown. Active-low logic input. In OFF mode, supply current is reduced below 1µA and
—
8
7
8
OFF
LBI
V
OUT
= 0V
Low-Battery comparator Input. Tie to IN when not used.
3.3V for the MAX882/MAX884. Ad d itiona l b loc ks
include a foldback current limiter, reverse-current pro-
tection, a thermal sensor, shutdown or standby logic,
and a low-battery-detection comparator.
_______________De t a ile d De s c rip t io n
The MAX882/MAX883/MAX884 are micropower, low-
dropout linear regulators designed primarily for battery-
p owe re d a p p lic a tions . The y fe a ture Dua l-Mod e ™
operation, allowing a fixed output of 5V for the MAX883
and 3.3V for the MAX882/MAX884, or an adjustable output
from 1.25V to 11V. These devices supply up to 200mA
while requiring less than 15µA quiescent current. As illus-
trated in Figure 1, they consist of a 1.20V reference, error
amplifier, MOSFET driver, P-channel pass transistor, dual-
mode comparator and feedback voltage divider.
In t e rn a l P -Ch a n n e l P a s s Tra n s is t o r
The MAX882/MAX883/MAX884 fe a ture a 200mA P-
channel MOSFET pass transistor. This provides several
advantages over similar designs using PNP pass tran-
sistors, including longer battery life.
The P-channel MOSFET requires no base drive, which
reduces quiescent current considerably. PNP based reg-
ulators waste large amounts of current in dropout when
the pass transistor saturates. They also use high base-
drive currents under large loads. The MAX882/MAX883/
MAX884 do not suffer from these problems and consume
only 11µA of quiescent current during light loads, heavy
loads, and dropout.
The 1.20V reference is connected to the error amplifier’s
inverting input. The error amplifier compares this refer-
ence with the selected feedback voltage and amplifies
the difference. The MOSFET driver reads the error signal
and applies the appropriate drive to the P-channel pass
transistor. If the feedback voltage is lower than the refer-
ence, the pass transistor’s gate is pulled lower, allowing
more current to pass and increasing the output voltage. If
the feedback voltage is too high, the pass transistor gate
is pulled up, allowing less current to pass to the output.
Ou t p u t Vo lt a g e S e le c t io n
The MAX882/MAX883/MAX884 feature Dual Mode™
operation. In preset voltage mode, the MAX883’s out-
put is set to 5V and the MAX882/MAX884’s output is set
to 3.3V, using internal trimmed feedback resistors.
Select this mode by connecting SET to ground.
The output voltage is fed back through either an inter-
nal resistor voltage divider connected to the OUT pin,
or an external resistor network connected to the SET
pin. The dual-mode comparator examines the SET pin
voltage and selects the feedback path used. If the SET
pin is below 65mV, internal feedback is used and the
output voltage is regulated to 5V for the MAX883 or
In preset voltage mode, impedances between SET and
ground should be less than 100kΩ. Otherwise, spurious
conditions could cause the voltage at SET to exceed
the 65mV dual-mode threshold.
_______________________________________________________________________________________
7
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IN
LBI
LOW-BATTERY
COMPARATOR
REVERSE-
CURRENT
PROTECTION
LBO
MOSFET DRIVER
WITH FOLDBACK
CURRENT LIMIT
P
N
ERROR AMP
SHUT-
DOWN
LOGIC
OFF
(STBY)
OUT
SET
1.20V
REFERENCE
DUAL-MODE
COMPARATOR
R1
R2
THERMAL
SENSOR
65mV
GND
23/MAX84
( ) ARE FOR MAX882
Figure 1. MAX882/MAX883/MAX884 Functional Diagram
In adjustable mode, the user selects an output voltage
in the 1.25V to 11V range by connecting two external
resistors, used as a voltage divider, to the SET pin
(Figure 2).
S t a n d b y Mo d e (MAX8 8 2 )
The MAX882 has a standby feature that disconnects
the input from the output when STBY is brought low, but
keeps all other circuitry awake. In this mode, V
OUT
drops to 0V, and the internal biasing circuitry (including
the low-battery comparator) remains on. The maximum
quiescent current during standby is 15µA. STBY is a
comparator input with the other input internally tied to
the reference voltage. Use a resistor network as shown
in Figure 3 to set a standby-mode threshold voltage for
undervoltage lockout. Connect STBY to IN for normal
operation.
The output voltage is set by the following equation:
R1
V
= V
1 +
OUT
SET
R2
where V
= 1.20V.
SET
To simplify resistor selection:
V
OUT
R1 = R2
− 1
V
SET
OFF Mo d e (MAX8 8 3 /MAX8 8 4 )
A low-log ic inp ut on the OFF p in s huts d own the
MAX883/MAX884. In this mode, the pass transistor,
control circuit, reference, and all biases are turned off,
and the supply current is reduced to less than 1µA.
LBO is undefined in OFF mode. Connect OFF to IN for
normal operation.
Since the input bias current at SET is nominally zero,
large resistance values can be used for R1 and R2 to
minimize power consumption without losing accuracy.
Up to 1.5MΩ is acceptable for R2. Since the V
toler-
SET
ance is less than ±40mV, the output can be set using
fixed resistors instead of trim pots.
8
_______________________________________________________________________________________
5 V/3 .3 V o r Ad ju s t a b le , Lo w -Dro p o u t ,
Lo w I , 2 0 0 m A Lin e a r Re g u la t o rs
Q
23/MAX84
INPUT
VOLTAGE
OUTPUT
VOLTAGE
IN
OUT
SET
IN
LBI
OUT
OUTPUT
VOLTAGE
INPUT
VOLTAGE
LBI
R1
R2
R1
R2
MAX882
MAX882
MAX883
MAX884
LOAD
OFF
(STBY)
STBY
C
OUT
C
O.1µF
IN
C
C
2.2µF
IN
OUT
2.2µF
GND
GND SET
O.1µF
( ) ARE FOR MAX882
R1 + R2
R1+ R2
V
= V
STBY
, V = 1.20V
STBY
STBY TRIP
R2
V
= V
, V = 1.20V
SET
OUT SET
R2
Figure 2. Adjustable Output Using External Feedback
Resistors
Figure 3. Setting an Undervoltage Lockout Threshold Using
STBY
Fo ld b a c k Cu rre n t Lim it in g
The MAX882/MAX883/MAX884 also include a foldback
current limiter. It monitors and controls the pass transis-
tor’s gate voltage, estimating the output current and
limiting it to 430mA for output voltages above 0.8V and
P o w e r Dis s ip a t io n a n d Op e ra t in g Re g io n
Maximum power dissipation of the MAX882/MAX883/
MAX884 depends on the thermal resistance of the case
and circuit board, the temperature difference between
the d ie junc tion a nd a mb ie nt a ir, a nd the ra te of
air flow. The power dissipation across the device is
(V - V
) > 0.7V. If the output voltage drops below
IN
OUT
0.8V, implying a short-circuit condition, the output cur-
rent is limited to 170mA. The output can be shorted to
ground for 1 minute without damaging the device if the
P = I
is as follows:
(V - V
). The resulting power dissipation
OUT IN
OUT
(T − T )
J
A
P =
package can dissipate (V x 170mA) without exceed-
IN
(θ + θ
)
JB
BA
ing T = +150°C. When the output is greater than 0.8V
J
and (V - V
) < 0.7V (dropout operation), no current
IN
OUT
where (T - T ) is the temperature difference between
J
A
limiting is allowed, to provide maximum load drive.
the MAX882/MAX883/MAX884 die junction and the sur-
rounding air, θ (or θ ) is the thermal resistance of
JB
JC
Th e rm a l Ove rlo a d P ro t e c t io n
Thermal overload protection limits total power dissipa-
tion in the MAX882/MAX883/MAX884. When the junc-
the package chosen, and θ
is the thermal resistance
BA
through the printed circuit board, copper traces, and
other materials to the surrounding air.
tion temperature exceeds T =+160°C, the thermal
J
The 8-p in s ma ll-outline p a c ka g e for the MAX882/
MAX883/MAX884 features a special lead frame with a
lower thermal resistance and higher allowable power
dissipation. This package’s thermal resistance package
is θ = 53°C/W, compared with θ = 110°C/W for an
sensor sends a signal to the shutdown logic, turning off
the pass transistor and allowing the IC to cool. The
thermal sensor turns the pass transistor on again after
the IC’s junction temperature cools by 10°C, resulting in
a pulsed output during thermal overload conditions.
JB
JB
8-pin plastic DIP package and θ = 125°C/W for an 8-
pin ceramic DIP package.
JB
Thermal overload protection is designed to protect the
MAX882/MAX883/MAX884 if fault conditions occur. It is
not inte nd e d to b e us e d a s a n op e ra ting mod e .
Prolonged operation in thermal shutdown mode may
reduce the IC’s reliability. For continual operation, do
not exceed the absolute maximum junction temperature
rating of T = +150°C.
J
_______________________________________________________________________________________
9
5 V/3 .3 V o r Ad ju s t a b le , Lo w -Dro p o u t ,
Lo w I , 2 0 0 m A Lin e a r Re g u la t o rs
Q
1.6
1.5
250
200
MAX883, V
= 5V
MAXIMUM POWER
DISSIPATION LIMIT
OUT
8-PIN SO PACKAGE
MAXIMUM CURRENT
PLASTIC DIP
77.4cm2,
SINGLE-SIDED BOARD
1oz. COPPER
GLASS EPOXY,
1.4
1.3
1.2
1.1
1.0
0.9
HIGH-
POWER
SOIC
150
100
50
T = +125°C,
J
T
A
= +25°C, STILL AIR
CERAMIC DIP
OPERATING
REGION AT
= +25°C
T
A
T = +125°C
J
0
0.1cm2
1cm2
10cm2
1.55in2
100cm2
15.5in2
2
3
4
5
6
7
8
9
10 11 12 13
0.0155in2
0.155in2
SUPPLY VOLTAGE (V)
COPPER GROUND PAD AREA
Figure 4. Typical Maximum Power Dissipation vs. Ground
Pad Area
Figure 5a. Safe Operating Regions: MAX882/MAX884 Maximum
Output Current vs. Supply Voltage
The GND pins of the MAX882/MAX883/MAX884 SOIC
package perform the dual function of providing an elect-
rical connection to ground and channeling heat away. Con-
nect all GND pins to ground using a large pad or ground
plane. Where this is impossible, place a copper plane on an
adjacent layer. For a given power dissipation, the pad
should exceed the associated dimensions in Figure 4.
23/MAX84
250
MAXIMUM POWER
DISSIPATION LIMIT
MAXIMUM CURRENT
200
HIGH-
POWER
SOIC
Figure 4 assumes the IC is in an 8-pin small-outline pack-
age that has a maximum junction temperature of +125°C
and is soldered directly to the pad; it also has a +25°C
ambient air temperature and no other heat sources. Use
larger pad sizes for other packages, lower junction tem-
peratures, higher ambient temperatures, or conditions
where the IC is not soldered directly to the heat-sinking
ground pad. When operating C and E grade parts up to a
150
PLASTIC DIP
100
CERAMIC DIP
OPERATING
50
REGION AT
T
= +25°C
A
J
T = +125°C
0
T
J
of +125°C, expect performance similar to M grade
4
5
6
7
8
9
10 11 12 13
specifications. For T between +125°C and +150°C, the
J
SUPPLY VOLTAGE (V)
output voltage may drift more.
The MAX882/MAX883/MAX884 can regulate currents up
to 250mA and operate with input voltages up to 11.5V, but
not simultaneously. High output currents can only be sus-
tained when input-output differential voltages are small, as
shown in Figure 5. Maximum power dissipation depends
on packaging, temperature, and air flow. The maximum
output current is as follows:
Figure 5b. Safe Operating Regions: MAX883 Maximum Output
Current vs. Supply Voltage
P(T − T )
J
A
I
=
OUT(MAX)
(V − V
)100°C
IN
OUT
where P is derived from Figure 4.
10 ______________________________________________________________________________________
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23/MAX84
OUTPUT
VOLTAGE
OUT
IN
ON/OFF
OFF (STBY)
IN
OUTPUT
VOLTAGE
BATTERY
OFF (STBY)
R1
R2
*
R3
OUT
INPUT
VOLTAGE
MAX882
LBI
LBO
LBI
MAX882
MAX883
MAX884
GND
MAX883
MAX884
SET
POWER-
C
2.2µF
FAIL
OUT
BATTERY
C
O.1µF
IN
C
INDICATION
OUT
GND
2.2µF
C
IN
SET
O.1µF
( ) ARE FOR MAX882
R1 + R2
( ) ARE FOR MAX882
V
LBI TRIP
= V
, V = 1.20V
LBI
LBI
R2
* OPTIONAL REVERSE BATTERY PROTECTION
Figure 6. Using the Low-Battery Comparator to Monitor Battery
Voltage
Figure 7. Typical 3.3V or 5V Linear Regulator Circuit
Re ve rs e -Cu rre n t P ro t e c t io n
The MAX882/MAX883/MAX884 have a unique protection
scheme that limits reverse currents when the input volt-
age falls below the output. It monitors the voltages on IN
and OUT and switches the IC’s substrate and power bus
to the more positive of the two. The control circuitry is
then able to remain functioning and turn the pass transis-
tor off, limiting reverse currents back through to the input
of the device. In this mode, typical current into OUT to
__________Ap p lic a t io n s In fo rm a t io n
The MAX882/MAX883/MAX884 are series linear regula-
tors designed primarily for battery-powered systems.
Figure 7 shows a typical application.
S t a n d b y Mo d e vs . OFF Mo d e
STBY is a comparator input that allows the user to set
the standby-mode threshold voltage, while OFF is a
logic-level input. When in standby mode, the output is
disconnected from the input, but the biasing circuitry
(including the low-battery comparator) is kept alive,
causing the device to draw around 7µA. Standby mode
is useful in applications where a low-battery compara-
tor function is still needed in shutdown.
GND is 15µA at V
= 3.3V and 50µA at V
= 5V.
OUT
OUT
Reverse-current protection activates when the voltage
on IN falls 6mV (or 20mV maximum) below the voltage
on OUT. Before this happens, currents as high as sev-
eral milliamperes can flow back through the device.
A logic low at the OFF pin turns off all biasing circuitry,
including the LBI/LBO comparator, and reduces supply
current to less than 1µA. OFF mode is useful for maxi-
mizing battery life. There is little difference in the time it
takes to exit standby mode or OFF mode.
Lo w -Ba t t e ry-De t e c t io n Co m p a ra t o r
The MAX882/MAX883/MAX884 provide a low-battery com-
parator that compares the voltage on the LBI pin to the
1.20V internal reference. LBO, an open-drain output, goes
low when LBI is below 1.20V. Hysteresis of 7mV has been
added to the low-battery comparator to provide noise
immunity during switching. LBO remains functional in stand-
by mode for the MAX882, but is undefined in OFF mode for
the MAX883 and MAX884. Tie LBI to IN when not used.
Ou t p u t Ca p a c it o r S e le c t io n
a n d Re g u la t o r S t a b ilit y
An output filter capacitor is required at the MAX882/
MAX883/MAX884 OUT p in. The minimum outp ut
capacitance required for stability is 2.2µF.
Use a resistor-divider network as shown in Figure 6 to set
the low-battery trip voltage. Current into the LBI input is
±50nA maximum, so R2 can be as large as 1MΩ. Add
extra noise immunity by connecting a small capacitor
from LBI to GND. Additional hysteresis can be added by
connecting a high-value resistor from LBI to LBO.
* Tie LBI to IN when not used.
______________________________________________________________________________________ 11
5 V/3 .3 V o r Ad ju s t a b le , Lo w -Dro p o u t ,
Lo w I , 2 0 0 m A Lin e a r Re g u la t o rs
Q
80
70
60
50
40
A: C
= 1µF
= 10µF
= 100µF
OUT
B: C
OUT
C: C
OUT
60
50
I
= 1mA
OUT
40
30
30
C
20
10
0
MAX884
∆V = 1V
B
MAX883
∆V = 1V
20
10
0
A
IN
P-P
IN
P-P
C
= 0µF
IN
OUT
C = 0µF
IN
C
= 2.2µF
I
OUT
= 100mA
I
= 100mA
OUT
100 101
102
103
104
105
106
101
102
103
104
105
106
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 8a. Power-Supply Rejection Ratio vs. Ripple Frequency
for Light and Heavy Loads
Figure 8b. Power-Supply Rejection Ratio vs. Ripple Frequency
for Various Output Capacitances
The filter capacitor’s size depends primarily on the
desired power-up time and load-transient responses.
Load-transient response is improved by using larger
output capacitors.
No is e
23/MAX84
The MAX882/MAX883/MAX884 exhibit up to 4mV
of
p-p
noise during normal operation. This is negligible in
most applications. When using the MAX882/MAX883/
MAX884 for applications that include analog-to-digital
converters (ADCs) with resolutions greater than 12 bits,
consider the ADC’s power-supply rejection specifica-
tions . Re fe r to the outp ut nois e p lot in the Typ ic a l
Operating Characteristics section.
The output capacitor’s equivalent series resistance
(ESR) will not affect stability as long as you observe the
minimum capacitance requirement. The type of capaci-
tor selected is not critical, but it must remain above the
minimum va lue ove r the full ope ra ting te mp e ra ture
range.
P S RR a n d Op e ra t io n fro m
S o u rc e s Ot h e r t h a n Ba t t e rie s
In p u t Byp a s s Ca p a c it o r
Normally, use 0.1µF to 10µF capacitors on the MAX882/
MAX883/MAX884 input. The best value depends pri-
The MAX882/MAX883/MAX884 a re d e s ig ne d to
achieve low dropout voltages and low quiescent cur-
rents in battery-powered systems. However, to gain
these benefits, the devices must trade away power-
supply noise rejection, as well as swift response to sup-
p ly va ria tions a nd loa d tra ns ie nts . For a 1mA loa d
c urre nt, p owe r-s up p ly re je c tion ra ng e s from 60d B
down to 20dB at 2kHz. At higher frequencies, the cir-
cuit depends primarily on the characteristics of the out-
put capacitor, and the PSRR increases (Figure 8).
marily on the power-up slew rate of V , and on load
IN
and line transients. Larger input capacitor values pro-
vide better supply-noise rejection and line-transient
response, as well as improved performance, when the
supply has a high AC impedance. The type of input
bypass capacitor used is not critical.
12 ______________________________________________________________________________________
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23/MAX84
In p u t -Ou t p u t (Dro p o u t ) Vo lt a g e
A regulator’s minimum input-output voltage differential
(or dropout voltage) determines the lowest usable sup-
ply voltage. In battery-powered systems, this deter-
INPUT
VOLTAGE
OUTPUT
VOLTAGE
mines the useful end-of-life battery voltage. Because
the MAX882/MAX883/MAX884 use a P-channel MOS-
FET pass transistor, their dropout voltage is a function
IN
OUT
LBI
of R
multiplied by the load current (see Electrical
DS(ON)
C
2.2µF
OUT
Characteristics). Quickly stepping up the input voltage
from the dropout voltage can result in overshoot.
R1
R2
MAX882
D2
STBY
S h o rt -Te rm Ba t t e ry Ba c k u p
Us in g t h e MAX8 8 2
C
O.1µF
IN
BACKUP
BATTERY
GND SET
Figure 9 illustrates a scheme for implementing battery
backup for 3.3V circuits using the MAX882. When the
supply voltage drops below some user-specified value
based on resistors R1 and R2, the standby function
a c tiva te s , turning off the MAX882’s outp ut. Und e r
these conditions, the backup battery supplies power to
the load. Reverse current protection prevents the bat-
tery from draining back through the regulator to the
input.
Figure 9. Short-Term Battery Backup Using the MAX882
When operating from sources other than batteries, sup-
p ly-nois e re je c tion a nd tra ns ie nt re s p ons e c a n b e
improved by increasing the values of the input and out-
put capacitors and employing passive filtering tech-
niques. Do not use power supplies with ripple voltage
exceeding 200mV at 100kHz.
This application is limited to short-term battery backup
for 3.3V circuits. The current drawn by the MAX882’s
OUT pin at 3.3V during reverse current protection is
typically 8µA. It should not be used with the MAX883
and MAX884, since the OFF pin is a logic input, and
indeterminate inputs can cause the regulator to turn on
intermittently, draining the battery.
Ove rs h o o t a n d Tra n s ie n t Co n s id e ra t io n s
The Typical Operating Characteristics section shows
power-up, supply, and load-transient response graphs.
On the load-transient graphs, two components of the
output response can be observed: a DC shift from the
output impedance due to the different load currents,
and the transient response. Typical transients for step
changes in the load current from 50mA to 250mA are
200mV. Increasing the output capacitor’s value attenu-
ates transient spikes.
Re ve rs e Ba t t e ry P ro t e c t io n
Reverse battery protection can be added by including
an inexpensive Schottky diode between the battery
input and the regulator circuit, as shown in Figure 7.
However, the dropout voltage of the regulator will be
increased by the forward voltage drop of the diode. For
example, the forward voltage of a standard 1N5817
Schottky diode is typically 0.29V at 200mA.
During recovery from shutdown, overshoot is negligible
if the output voltage has been given time to decay ade-
quately. During power-up from V = 0V, overshoot is
IN
typically less than 1% of V
.
OUT
______________________________________________________________________________________ 13
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Lo w I , 2 0 0 m A Lin e a r Re g u la t o rs
Q
_Ord e rin g In fo rm a t io n (c o n t in u e d )
___________________Ch ip To p o g ra p h y
PART
TEMP. RANGE
0°C to +70°C
PIN-PACKAGE
8 Plastic DIP
8 SO
LB0
GND
MAX883CPA
MAX883CSA
MAX883C/D
MAX883EPA
MAX883ESA
MAX883MJA
MAX884CPA
MAX884CSA
MAX884C/D
MAX884EPA
MAX884ESA
MAX884MJA
0°C to +70°C
0°C to +70°C
Dice*
LBI
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
0°C to +70°C
8 Plastic DIP
8 SO
SET
OUT
OFF (MAX883/4)
STBY (MAX882)
8 CERDIP**
8 Plastic DIP
8 SO
0. 085"
(2. 159mm)
0°C to +70°C
0°C to +70°C
Dice*
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
8 Plastic DIP
8 SO
8 CERDIP**
* Dice are tested at T = +25°C, DC parameters only.
J
** Contact factory for availability.
IN
OUT
0. 080"
(2. 032mm)
TRANSISTOR COUNT: 151
23/MAX84
NO DIRECT SUBSTRATE CONNECTION. THE N-SUB-
STRATE IS INTERNALLY SWITCHED BETWEEN THE
MORE POSITIVE OF IN OR OUT.
14 ______________________________________________________________________________________
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Q
23/MAX84
________________________________________________________P a c k a g e In fo rm a t io n
INCHES
MILLIMETERS
DIM
E
MIN
MAX
0.200
–
MIN
–
MAX
5.08
–
A
–
E1
D
A1 0.015
A2 0.125
A3 0.055
0.38
3.18
1.40
0.41
1.14
0.20
0.13
7.62
6.10
2.54
7.62
–
0.175
0.080
0.022
0.065
0.012
0.080
0.325
0.310
–
4.45
2.03
0.56
1.65
0.30
2.03
8.26
7.87
–
A3
A2
A1
A
L
B
0.016
B1 0.045
0.008
D1 0.005
0.300
E1 0.240
0.100
eA 0.300
C
0° - 15°
E
C
e
e
B1
eA
eB
–
–
B
eB
L
–
0.400
0.150
10.16
3.81
0.115
2.92
D1
INCHES
MILLIMETERS
PKG. DIM
PINS
Plastic DIP
PLASTIC
DUAL-IN-LINE
PACKAGE
(0.300 in.)
MIN
MAX MIN
MAX
8
P
P
P
P
P
N
D
D
D
D
D
D
0.348 0.390 8.84
9.91
14
16
18
20
24
0.735 0.765 18.67 19.43
0.745 0.765 18.92 19.43
0.885 0.915 22.48 23.24
1.015 1.045 25.78 26.54
1.14 1.265 28.96 32.13
21-0043A
INCHES
MILLIMETERS
DIM
MIN
0.053
MAX
0.069
0.010
0.019
0.010
0.157
MIN
1.35
0.10
0.35
0.19
3.80
MAX
1.75
0.25
0.49
0.25
4.00
A
D
A1 0.004
B
C
E
e
0.014
0.007
0.150
0°-8°
A
0.101mm
0.004in.
0.050
1.27
e
H
L
0.228
0.016
0.244
0.050
5.80
0.40
6.20
1.27
A1
C
B
L
INCHES
MILLIMETERS
DIM PINS
Narrow SO
SMALL-OUTLINE
PACKAGE
MIN MAX
MIN
MAX
5.00
8.75
8
0.189 0.197 4.80
D
D
D
E
H
14 0.337 0.344 8.55
16 0.386 0.394 9.80 10.00
21-0041A
(0.150 in.)
______________________________________________________________________________________ 15
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Lo w I , 2 0 0 m A Lin e a r Re g u la t o rs
Q
___________________________________________P a c k a g e In fo rm a t io n (c o n t in u e d )
INCHES
MIN
MILLIMETERS
DIM
MAX
0.200
0.023
0.065
0.015
0.310
0.320
MIN
–
MAX
5.08
0.58
1.65
0.38
7.87
8.13
E1
E
A
B
–
0.014
0.36
0.97
0.20
5.59
7.37
D
B1 0.038
A
C
E
0.008
0.220
E1 0.290
e
L
0.100
2.54
0.125
0.150
0.015
–
0.200
–
3.18
3.81
0.38
–
5.08
–
0°-15°
C
Q
L1
Q
S
L
L1
0.070
0.098
–
1.78
2.49
–
e
B1
S1 0.005
0.13
B
S1
S
INCHES
MILLIMETERS
DIM PINS
MIN
–
MAX MIN MAX
CERDIP
D
D
D
D
D
D
8
0.405
0.785
0.840
0.960
1.060
1.280
–
–
–
–
–
–
10.29
19.94
21.34
24.38
26.92
CERAMIC DUAL-IN-LINE
PACKAGE
14
16
18
20
24
–
–
–
(0.300 in.)
–
23/MAX84
–
32.51
21-0045A
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.
16 __________________Ma x im In t e g ra t e d P ro d u c t s , 1 2 0 S a n Ga b rie l Drive , S u n n yva le , CA 9 4 0 8 6 (4 0 8 ) 7 3 7 -7 6 0 0
© 1995 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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