19-1679; Rev 2; 12/07
12V, Ultra-Low-I
Q
, Low-Dropout
Linear Regulators with POK
General Description
The MAX8880/MAX8881 are ultra-low supply current,
low-dropout linear regulators, capable of delivering up
to 200mA. They are designed for battery-powered
applications where reverse battery protection and long
battery life are critical.
These regulators’ low 3.5µA supply current extends bat-
tery life in applications with long standby periods. Unlike
PNP-based designs, a 2Ω PMOS device maintains ultra-
low supply current throughout the entire operating range
and in dropout. The parts are internally protected from
output short circuits, reverse battery connection, and
thermal overload. An internal power-OK (POK) com-
parator indicates when the output is out of regulation.
The MAX8880 output is adjustable from 1.25V to 5V
using an external resistor-divider. The MAX8881 pro-
vides only factory-preset output voltages of 1.8V, 2.5V,
3.3V, or 5V (see
Ordering Information).
The devices are
available in 6-pin SOT23 and 6-pin TDFN packages.
♦
3.5µA Supply Current at 12V
♦
Reverse Battery Protection
♦
2.5V to 12V Input Voltage Range
♦
±1.5% Output Voltage Accuracy
♦
200mA max Output Current
♦
2Ω PMOS Output Device
♦
Short-Circuit and Thermal Overload Protection
♦
POK Output for Out-of-Regulation Indicator
♦
Fixed 1.8V, 2.5V, 3.3V, and 5V (MAX8881)
Adjustable from 1.25V to 5V (MAX8880)
♦
Tiny 6-Pin SOT23 Package
♦
Thin 6-Pin TDFN Package
Features
MAX8880/MAX8881
________________________Applications
Smoke Detectors
Battery-Powered Alarms
Remote Transmitters
Smart Battery Packs
PDAs
Handy Terminals
CMOS Backup Power
Real-Time Clocks
Pin Configurations
TOP VIEW
IN
1
6
POK
POK SHDN
6
5
IN
4
Typical Operating Circuit
V
IN
2.5V TO 12V
1μF
V
OUT
1.25V TO 5V
UP TO 200mA
4.7μF
IN
OUT
FB
GND
2
MAX8880
MAX8881
5
SHDN
MAX8880
ON
1
2
3
MAX8881
REGULATION OK
SHDN
GND
POK
OUT
3
4
FB
FB
GND OUT
TDFN
3mm x 3mm
OFF
SOT23-6
Ordering Information
PART
MAX8880EUT-T
MAX8880ETT-T
MAX8881EUT18-T
MAX8881EUT25-T
MAX8881EUT33-T
MAX8881EUT50-T
OUTPUT
Adjustable
Adjustable
1.8V
2.5V
3.3V
5.0V
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
6 SOT23-6
6 TDFN
6 SOT23-6
6 SOT23-6
6 SOT23-6
6 SOT23-6
TOP MARK
AAHR
AGS
AAHS
AAHT
AAHU
AAHV
________________________________________________________________
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.
12V, Ultra-Low-I
Q
, Low-Dropout
Linear Regulators with POK
MAX8880/MAX8881
ABSOLUTE MAXIMUM RATINGS
IN to GND ................................................................-14V to +14V
SHDN
to GND .............................................-0.3V to (V
IN
+ 0.3V),
-0.3V to +0.3V when V
IN
< 0V
OUT, FB to GND...............................-0.3V to +6V when V
IN
> 5.7V,
-0.3V to (V
IN
+ 0.3V) when 0V
≤
V
IN
≤
5.7V,
-0.3V to +0.3V when V
IN
< 0V
POK to GND ...........................................................-0.3V to +14V
OUT Continuous Current...................................................200mA
OUT Short Circuit...........................................................Indefinite
Continuous Power Dissipation (T
A
= +70°C)
6-Pin SOT23 (derate 8.7mW/°C above +70°C)...........696mW
6-Pin TDFN (derate 24.4mW/°C above +70°C) ........1951mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature.........................................-65°C to +165°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
(V
IN
= V
OUT
+ 1V,
SHDN
= IN, C
OUT
= 4.7µF, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Input Voltage Range
Supply Current
Shutdown Supply Current
Input Undervoltage Lockout
FB Voltage, Adjustable
Mode
SYMBOL
V
IN
I
IN
I
IN(SHDN)
V
UVLO
V
FB
MAX8880,
I
OUT
= 20mA
T
A
= +25°C
T
A
= 0°C to +85°C
T
A
= -40°C to +85°C
T
A
= +25°C
T
A
= 0°C to +85°C
T
A
= -40°C to +85°C
OUT Voltage Range
OUT Line Regulation
OUT Load Regulation (Note 3)
Current Limit (Note 3)
Dropout Voltage (Notes 3, 4)
IN Reverse Leakage Current
Foldback Current Limit
SHDN Input Threshold
SHDN Input Bias Current
FB Input Bias Current
POK Trip Threshold
Hysteresis
POK Off-Current
POK Low Voltage
I
POK
V
POK
V
POK
= 12V, T
A
= +25°C
I
POK
= 1mA
50
I
FB
I
OUT
ΔV
DO
I
IN(REV)
I
OUT(SC)
V
IH
V
IL
I
OUT
= 50mA
V
IN
= -12V, V
SHDN
= 0
V
IN
= 5V, V
OUT
= 0
V
IN
= 2.5V to 12V
V
SHDN
= 0 to 12V, T
A
= +25°C
FB = 1.25V, T
A
= +25°C, MAX8880 only
Falling
T
A
= +25°C
T
A
= -40°C to +85°C
2
0.5
-100
0
87.5
86
1.5
100
200
2
90.5
100
20
93.5
95
250
V
OUT
MAX8880
V
IN
= V
OUT
+ 1V to 12V
I
OUT
= 10μA to 100mA
200
1.238
1.232
1.219
-1.5
-2
-3
1.25
0.01
0.006
400
100
200
1
V
IN
= 12V
V
SHDN
= 0, V
IN
= 12V, V
OUT
= 0, T
A
= +25°C
CONDITIONS
MIN
2.5
3.5
1.5
2.1
1.257
TYP
MAX
12
10
3
2.4
1.276
1.282
1.295
1.5
2
3
5.5
0.05
0.015
V
%/V
%/mA
mA
mV
mA
mA
V
nA
nA
% of
V
OUT
nA
mV
%
V
UNITS
V
μA
μA
V
OUT Voltage Accuracy
(Note 2)
MAX8881,
I
OUT
= 20mA
2
_______________________________________________________________________________________
12V, Ultra-Low-I
Q
, Low-Dropout
Linear Regulators with POK
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
OUT
+ 1V,
SHDN
= IN, C
OUT
= 4.7µF, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Thermal Shutdown Threshold
OUT Noise
SYMBOL
T
TSD
CONDITIONS
(Hysteresis = 15°C)
MIN
TYP
160
300
MAX
UNITS
°C
μV
RMS
MAX8880/MAX8881
V
OUT(NOISE)
f = 10Hz to 100kHz, I
OUT
= 1mA
Note 1:
Note 2:
Note 3:
Note 4:
All devices are 100% production tested at T
A
= +25°C. All temperature limits are guaranteed by design.
Output accuracy with respect to nominal preset voltages. FB = OUT.
This specification is valid for V
IN
> 3V.
The dropout voltage is defined as V
IN
- V
OUT
, when V
OUT
is 100mV below the value of V
OUT
for V
IN
= V
OUT
+ 1V.
Typical Operating Characteristics
(V
IN
= 5V, V
OUT
= 3.3V, I
OUT
= 30mA, C
OUT
= 4.7µF, T
A
= +25°C, unless otherwise noted. See Figure 1.)
SUPPLY CURRENT
vs. INPUT VOLTAGE
MAX8880/1-01
SUPPLY CURRENT
vs. TEMPERATURE
4.5
4.0
SUPPLY CURRENT (µA)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
V
OUT
= 1.8V
MAX8880/1-02
DROPOUT VOLTAGE
vs. LOAD CURRENT
450
400
DROPOUT VOLTAGE (mV)
350
300
250
200
150
100
50
0
T
A
= -40°C
0
50
100
150
200
T
A
= +25°C
T
A
= +85°C
MAX8880/1-03
4.5
4.0
SUPPLY CURRENT (µA)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0
2
4
6
8
10
NO LOAD
I
OUT
= 30 mA
5.0
500
12
-40
-15
10
35
60
85
INPUT VOLTAGE (V)
TEMPERATURE (°C)
LOAD CURRENT (mA)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX8880/1-04
OUTPUT NOISE SPECTRAL DENSITY
vs. FREQUENCY
MAX186-14A
OUTPUT NOISE
vs. LOAD CURRENT
350
OUTPUT NOISE (μV
RMS
)
300
250
200
150
100
50
V
OUT
= 1.8V
0
20
40
60
80
100
C
OUT
= 4.7μF
C
OUT
= 1.0μF
MAX8880/1-06
70
60
50
40
30
20
10
0
0.1
1
10
100
1k
10
400
NOISE (µV/√Hz)
1
PSRR (dB)
0.10
0.01
10k
10
100
1k
FREQUENCY (Hz)
10k
100k
FREQUENCY (Hz)
0
LOAD CURRENT (mA)
_______________________________________________________________________________________
3
12V, Ultra-Low-I
Q
, Low-Dropout
Linear Regulators with POK
MAX8880/MAX8881
Typical Operating Characteristics (continued)
(V
IN
= 5V, V
OUT
= 3.3V, I
OUT
= 30mA, C
OUT
= 4.7µF, T
A
= +25°C, unless otherwise noted. See Figure 1.)
SUPPLY CURRENT
OUTPUT VOLTAGE ERROR
OUTPUT VOLTAGE
vs. LOAD CURRENT
vs. LOAD CURRENT
vs. INPUT VOLTAGE
MAX8880/1-08
0.1
OUTPUT VOLTAGE ERROR (%)
0
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
0
50
100
150
MAX8880/1-07
3.00
OUTPUT VOTLAGE (V)
2.50
2.00
1.50
1.00
0.50
3.7
SUPPLY CURRENT (μA)
3.6
3.5
3.4
3.3
200
0
50
100
LOAD CURRENT (mA)
150
200
LOAD CURRENT (mA)
0
0
2
4
6
8
10
12
14
INPUT VOLTAGE (V)
CHANGE FROM NOMINAL OUTPUT
VOLTAGE vs. TEMPERATURE
0.15
CHANGE FROM NOMINALOUTPUT
VOLTAGE (%)
0.10
0.05
0
-0.05
-0.10
-0.15
-0.20
-40
-15
10
35
60
85
TEMPERATURE (°C)
0.1
0
C
OUT
ESR (Ω)
10
MAX8880/1-10
REGION OF STABLE C
OUT
ESR
vs. OUTPUT CURRENT
MAX8880/1-11
LINE-TRANSIENT RESPONSE
MAX8880/1-12
0.20
100
C
OUT
= 10µF
1
C
OUT
= 4.7µF
STABLE REGION
50
100
150
200
200µs/div
C
H1
= V
IN
, 500mV/div, AC COUPLED
C
H2
= V
OUT
, 20mV/div, AC COUPLED
V
OUT
= 5V, I
OUT
= 5mA
OUTPUT CURRENT (mA)
LOAD-TRANSIENT RESPONSE
MAX8880/1-13
LOAD-TRANSIENT RESPONSE
NEAR DROPOUT
MAX8880/1-14
TURN-ON RESPONSE
MAX8880/1-15
32.5mA
32.5mA
4V
1.25mA
1.25mA
400µs/div
C
H1
= I
OUT
, 12.5mA/div
C
H2
= V
OUT
, 100mV/div, AC COUPLED
V
OUT(NOMINAL)
= 5V, V
IN
= 9V
400µs/div
C
H1
= I
OUT
, 12.5mA/div
C
H2
= V
OUT
, 100mV/div, AC COUPLED
V
IN
= 5.2V, V
OUT(NOMINAL)
= 5V
C
H1
= SHDN, 2V/div
C
H2
= V
OUT
, 1V/div
V
IN
= 4.0V
100µs/div
4
_______________________________________________________________________________________
MAX8880/1-09
0.2
3.8
3.50
9.75V
9V
1.8V
12V, Ultra-Low-I
Q
, Low-Dropout
Linear Regulators with POK
Pin Description
PIN
MAX888_ (SOT)
1
2
3
4
MAX888_ (TDFN)
4
2
3
1
NAME
IN
GND
OUT
FB
FUNCTION
Input Voltage. Bypass with a 1µF capacitor to GND.
Ground
Output Voltage. Bypass with a 4.7µF capacitor (<0.5Ω ESR) to GND for load
currents up to 200mA. For load currents up to 40mA, 1µF is acceptable.
Feedback Set Point, 1.25V (MAX8880 only). Output sense, connect to OUT
externally (MAX8881 only).
ON/OFF Control. Regulator is ON when V
SHDN
> 2V. If unused, connect to
IN. If reverse battery protection of the
SHDN
input is desired, connect a
100kΩ resistor in series with
SHDN.
POK Output, Open Drain. Low when OUT is out of regulation or in shutdown.
Connect POK to OUT through a high-value resistor for a simple error
Exposed paddle (TDFN only). Connect to the circuit ground plane.
MAX8880/MAX8881
5
5
SHDN
6
—
6
—
POK
EP
Detailed Description
The MAX8880/MAX8881 are low-dropout, low-quies-
cent current linear regulators designed primarily for
battery-powered applications (Figure 1). The MAX8880
provides an adjustable output voltage from 1.25V to 5V
using an external resistor-divider. The MAX8881 is
available in factory preset output voltages of 1.8V, 2.5V,
3.3V, and 5V. Both devices have a +1.25V reference,
error amplifier, MOSFET driver, and P-channel pass
transistor (Figure 2).
Low-Dropout Regulator
The 1.25V reference is connected to the error amplifi-
er’s inverting input. The error amplifier compares this
reference 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 reference voltage, the pass-transistor gate is
V
IN
2.5V TO 12V
C1
1μF
pulled lower, allowing more current to pass, increasing
the output voltage. If the feedback voltage is higher
than the reference voltage, the pass-transistor gate is
driven higher, allowing less current to pass to the out-
put. The output voltage is fed back through either an
internal resistor voltage divider by externally connect-
ing FB to OUT (MAX8881), or an external resistor net-
work connected to FB (MAX8880). Additional blocks
include an output current limiter, reverse battery pro-
tection, a thermal sensor, shutdown logic, and a POK
comparator to indicate when the output is out of regula-
tion (Figure 2).
Internal P-Channel Pass Transistor
The MAX8880/MAX8881 feature a 2Ω P-channel MOS-
FET pass transistor. This provides advantages over
similar designs using PNP pass transistors, including
longer battery life. The P-channel MOSFET requires no
base drive, which reduces quiescent current consider-
ably. PNP-based regulators waste considerable current
in dropout when the pass transistor saturates. They
also use high base-drive currents under large loads.
The MAX8880/MAX8881 do not suffer from these prob-
lems and consume only 3.5µA of supply current (see
Typical Operating Characteristics).
V
OUT
IN
R2*
100k
OUT
FB
C2
4.7μF
MAX8881
REGULATION OK
SHDN
GND
POK
Dropout Voltage
A regulator’s minimum input-output differential (or
dropout voltage) determines the lowest usable supply
voltage. In battery-powered systems, this determines
the useful end-of-life battery voltage. Because the
MAX8880/MAX8881 use a P-channel MOSFET pass
transistor, their dropout voltage is R
DS(ON)
(2Ω) multi-
plied by the load current (see
Electrical Characteristics).
5
*OPTIONAL
Figure 1. Standard Application Circuit
_______________________________________________________________________________________
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