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19-4537; Rev 0; 3/09
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High PSRR, Low-Dropout, 150mA
Linear Regulators
General Description
The MAX8891/MAX8892 low-dropout (LDO) linear regu-
lators are designed to deliver up to 150mA continuous
output current. These regulators achieve a low 120mV
dropout for 120mA load current.
The MAX8891 only requires an input/output capacitor,
hence achieving the smallest PCB area. The
MAX8892’s output voltage can be adjusted with an
external divider.
The MAX8891 is preset to a variety of voltages in the
1.5V to 4.5V range. Designed with a p-channel
MOSFET series pass transistor, the MAX8891/MAX8892
maintain very low ground current (40µA).
The regulators are designed and optimized to work with
low-value, low-cost ceramic capacitors. The MAX8891/
MAX8892 require only 1µF (typ) of output capacitance
for stability with any load. When disabled, current con-
sumption drops to below 1µA.
These regulators are available in a tiny 5-pin SC70
package.
Applications
Cellular and Cordless Phones
PDA and Palmtop Computers
Base Stations
Bluetooth Portable Radios and Accessories
Wireless LANs
Digital Cameras
Personal Stereos
Portable and Battery-Powered Equipment
Output Voltage Selector Guide appears at end of data sheet.
Pin Configuration
Features
Space-Saving SC70 Package
65dB PSRR at 10kHz
120mV Dropout at 120mA Load
Stable with 1µF Ceramic Capacitor for Any Load
Guaranteed 150mA Output
Only Need Input and Output Capacitors (MAX8891)
Output Voltages: 1.5V, 1.8V, 2.5V, 2.6V, 2.7V, 2.8V,
2.85V, 3V, 3.3V, 4.5V (MAX8891) and Adjustable
(MAX8892)
Low 40µA Ground Current
Excellent Load/Line Transient
Overcurrent and Thermal Protection
Ordering Information
PART*
TEMP RANGE PIN-PACKAGE
MAX8891EXKxy+T -40°C to +85°C 5 SC70
MAX8892EXK+T
-40°C to +85°C 5 SC70
*xy is the output voltage code (see Output Voltage Selector
Guide). Other versions between 1.5V and 4.5V are available in
100mV increments. Contact factory for other versions.
+Denotes a lead(Pb)-free/RoHS-compliant package.
Typical Operating Circuits
INPUT
2V TO 6V
CIN = 1µF
ON
OFF
OUTPUT PRESET
1.5V TO 4.5V
IN OUT
MAX8891
SHDN
COUT = 1µF
GND
TOP VIEW
+
IN 1
5 OUT
MAX8891/
GND 2 MAX8892
SHDN 3
4
N.C. (MAX8891)
FB (MAX8892)
SC70
INPUT
2V TO 6V
CIN = 1µF
ON
OFF
IN OUT
MAX8892
SHDN
FB
GND
OUTPUT ADJUSTABLE
1.5V TO 4.5V
R1
COUT = 1µF
R2
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.

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High PSRR, Low-Dropout, 150mA
Linear Regulators
ABSOLUTE MAXIMUM RATINGS
IN to GND .................................................................-0.3V to +7V
Output Short-Circuit Duration.....................................Continuous
OUT, SHDN to GND ......................................-0.3V to (IN + 0.3V)
FB, BP, N.C. to GND..................................-0.3V to (OUT + 0.3V)
Continuous Power Dissipation (TA = +70°C)
5-Pin SC70 (derate 3.1mW/°C above +70°C) ..............0.247W
θJA
5-Pin SC70 .................................................................324°C/W
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
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
(VIN = VOUT + 0.5V, TA = -40°C to +85°C, unless otherwise noted. CIN = 1µF, COUT = 1µF. Typical values are at TA = +25°C; the
MAX8892 is tested with 2.45V output, unless otherwise noted.) (Note 1)
PARAMETER
Input Voltage Range
Output Voltage Accuracy
Maximum Output Current
Current Limit
Dropout Voltage (Note 2)
Ground Current
Line Regulation
Load Regulation
Shutdown Supply Current
Ripple Rejection
Output Noise Voltage (RMS)
SHDN Logic-Low Level
SHDN Logic-High Level
SHDN Input Bias Current
FB Input Bias Current (MAX8892)
Thermal Shutdown
Thermal-Shutdown Hysteresis
SYMBOL
VIN
IOUT
ILIM
IQ
VLNR
VLDR
ISHDN
PSRR
CONDITIONS
IOUT = 100µA to 80mA
OUT = 90% of nominal value
VOUT 3V, IOUT = 120mA
2.5V VOUT < 3V, IOUT = 120mA
2V VOUT < 2.5V, IOUT = 120mA
IOUT = 0.05mA
VIN = (VOUT + 0.5V) to 6V, IOUT = 0.1mA
IOUT = 1mA to 80mA
SHDN = 0V
TA = +25°C
TA = +85°C
f = 10kHz, IOUT = 10mA
f = 100Hz to 100kHz, ILOAD = 80mA
VIN = 2V to 6V
VIN = 2V to 6V
VIN = 6V, SHDN = TA = +25°C
0V or 6V
TA = +85°C
VIN = 6V,
VFB = 1.3V
TA = +25°C
TA = +85°C
MIN TYP MAX
26
-3 +3
150
200
120
135
180
40
0.001
0.003
0.003
1
0.05
65
230
0.4
1.5
0.01
0.006
0.01
160
10
0.1
Note 1: Limits are 100% tested at TA = +25°C. Limits over operating temperature range are guaranteed by design.
Note 2: Dropout is defined as VIN - VOUT when VOUT is 100mV below the value of VOUT for VIN = VOUT + 0.5V.
UNITS
V
%
mA
mA
mV
µA
%/V
%/mA
µA
dB
µV
V
V
µA
µA
°C
°C
2 _______________________________________________________________________________________

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High PSRR, Low-Dropout, 150mA
Linear Regulators
Typical Operating Characteristics
(VIN = VOUT + 0.5V, CIN = 1µF, COUT = 1µF, TA = +25°C, unless otherwise noted.)
OUTPUT VOLTAGE vs. INPUT VOLTAGE
3.0
2.5
IOUT = 0mA
2.0
1.5
1.0 IOUT = 120mA
0.5
0.0
0
12345
INPUT VOLTAGE (V)
6
OUTPUT VOLTAGE ACCURACY
vs. LOAD CURRENT
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
0
25 50 75 100 125 150
LOAD CURRENT (mA)
OUTPUT VOLTAGE ACCURACY
vs. TEMPERATURE
1.0
IOUT = 1mA
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
-40
-15 10 35 60
TEMPERATURE (°C)
85
DROPOUT VOLTAGE vs. LOAD CURRENT
200
180 TA = +25°C
160 TA = +85°C
140
120
100
80
60 TA = -40°C
40
20
0
0 25 50 75 100 125 150
LOAD CURRENT (mA)
DROPOUT VOLTAGE vs. OUTPUT VOLTAGE
250
IOUT = 80mA
200
150
100
50
0
2.0 2.2 2.4 2.6 2.8 3.0 3.2
OUTPUT (V)
GROUND PIN CURRENT vs. INPUT VOLTAGE
350
300
250
200
150
100
IOUT = 0mA
50
0
012345
INPUT VOLTAGE (V)
GROUND PIN CURRENT vs. LOAD CURRENT
350
300 VIN = 5.5V
250
200 VIN = 3.8V
150
100
50
0
0 25 50 75 100 125 150
LOAD CURRENT (mA)
GROUND PIN CURRENT vs. TEMPERATURE
50
45
40
35
30
-40
-15 10 35 60
TEMPERATURE (°C)
85
PSRR vs. FREQUENCY
90
80
70
60
50
40
30
20
10 ILOAD = 10mA
0
0.01 0.1
1
10
FREQUENCY (kHz)
100
1000
_______________________________________________________________________________________ 3

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High PSRR, Low-Dropout, 150mA
Linear Regulators
Typical Operating Characteristics (continued)
(VIN = VOUT + 0.5V, CIN = 1µF, COUT = 1µF, TA = +25°C, unless otherwise noted.)
LOAD TRANSIENT RESPONSE
dl/dt = 0.5mA/μs
MAX8891/2 toc10
10mA
50mA
dl/dt = 0.5mA/μs
VIN = 3.5V
10mA
ILOAD
25mA/div
VIN
10mV/div
LOAD TRANSIENT RESPONSE
dl/dt = 5mA/μs
MAX8891/2 toc11
10mA
50mA
dl/dt = 0.5mA/μs
VIN = 3.5V
10mA
ILOAD
25mA/div
VIN
10mV/div
LOAD TRANSIENT RESPONSE
dl/dt = 20mA/μs
MAX8891/2 toc12
10mA
50mA
dl/dt = 20mA/μs
VIN = 3.5V
10mA
ILOAD
25mA/div
VIN
10mV/div
200μs/div
VOUT
10mV/div
20μs/div
VOUT
10mV/div
4μs/div
VOUT
10mV/div
STARTUP WAVEFORM
MAX8891/2 toc13
VIN = 3.5V
RLOAD = 30Ω
ON
VSHDN
2V/div
OFF
SHUTDOWN WAVEFORM
MAX8891/2 toc14
ON VIN = 3.5V
RLOAD = 30Ω
VSHDN
OFF 2V/div
VOUT
500mV/div
VOUT
500mV/div
LINE TRANSIENT RESPONSE
dv/dt = 500mV/μs
MAX8891/2 toc15
RLOAD = 30Ω
4V dv/dt = 500mV/μs
4V
VIN
500mV/div
3.5V
VOUT
10mV/div
10μs/div
40μs/div
40μs/div
LINE TRANSIENT RESPONSE
dv/dt = 200mV/μs
MAX8891/2 toc16
RLOAD = 30Ω
5V dv/dt = 200mV/μs
5V
VIN
1V/div
REGION OF STABLE COUT ESR
vs. LOAD CURRENT
100
10
3.5V 1
VOUT
10mV/div
0.1
STABLE REGION
40μs/div
0.01
0
25 50 75 100 125 150
LOAD CURRENT (mA)
4 _______________________________________________________________________________________

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PIN
MAX8891 MAX8892
11
22
33
—4
4—
55
High PSRR, Low-Dropout, 150mA
Linear Regulators
Pin Description
NAME
IN
GND
SHDN
FB
N.C.
OUT
FUNCTION
Unregulated Input Supply
Ground
Shutdown. Pull low to disable the regulator.
Adjustable Output Feedback Point
Not Internally Connected
Regulated Output Voltage. Bypass with a capacitor to GND. See the Capacitor Selection
and Regulator Stability section for more details.
Detailed Description
The MAX8891/MAX8892 are low-dropout, low-quies-
cent current linear regulators designed for space-
restricted applications. The parts are available with
preset output voltages ranging from 1.5V to 4.5V in
100mV increments. These devices can supply loads up
to 150mA. As shown in the Functional Diagram, the
MAX8891 consists of an innovative bandgap core, error
amplifier, p-channel pass transistor, and internal feed-
back voltage-divider. The MAX8892 allows for
adjustable output with an external feedback network.
Additional blocks include a current limiter, thermal sen-
sor, and shutdown logic.
The 1.225V bandgap reference is connected to the
error amplifier’s inverting input. The error amplifier com-
pares this reference with the feedback voltage and
amplifies the difference. If the feedback voltage is lower
than the reference voltage, the pass-transistor gate is
pulled low. This allows more current to pass to the out-
put and increases the output voltage. If the feedback
voltage is too high, the pass transistor gate is pulled
high, allowing less current to pass to the output. The
output voltage is fed back through an internal (external
for the MAX8892) resistor voltage-divider connected to
the OUT pin.
Internal P-Channel Pass Transistor
The MAX8891/MAX8892 feature a 1Ω (typ) p-channel
MOSFET pass transistor. This provides several advan-
tages over similar designs using a PNP pass transistor,
including longer battery life. The p-channel MOSFET
requires no base drive, which considerably reduces qui-
escent current. PNP-based regulators waste consider-
able current in dropout when the pass transistor
saturates. They also use high base-drive current under
heavy loads. The MAX8891/MAX8892 do not suffer from
these problems and consume only 40µA of quiescent
current in light load and 220µA in dropout (see the
Typical Operating Characteristics).
Output Voltage Selection
The MAX8891 is supplied with factory-set output volt-
ages from 1.5V to 4.5V, in 100mV increments (see the
Ordering Information). The MAX8892 features a user-
adjustable output through an external feedback net-
work (see the Typical Operating Circuits).
To set the output of the MAX8892, use the following
equation:
R1 =
R2
X
⎝⎜
VOUT
VREF
-1⎞⎠⎟
where R2 is chosen to be less than 240kΩ and VREF =
1.225V. Use 1% or better resistors.
Shutdown
The MAX8891/MAX8892 feature a low-power shutdown
mode that reduces quiescent current less than 1µA.
Driving SHDN low disables the voltage reference, error
amplifier, gate-drive circuitry, and pass transistor (see
the Functional Diagram), and the device output enters a
high-impedance state. Connect SHDN to IN for normal
operation.
Current Limit
The MAX8891/MAX8892 include a current limiter, which
monitors and controls the pass transistor’s gate volt-
age, limiting the output current to 200mA. The output
can be continuously shorted to ground without damag-
ing the part.
_______________________________________________________________________________________ 5