MAX8885 - Maxim Integrated
19-1576; Rev 0; 10/99
150mA, Low-Dropout Linear Regulator
with Power-OK Output
Features
♦ Optimized for Low-Cost Tantalum Capacitors
♦ Pin Compatible with MIC5206
♦ Undervoltage Power-OK Output
♦ Preset Output Voltages (±1% accuracy)
♦ Guaranteed 150mA Output Current
♦ 85µA No-Load Supply Current
♦ Low 110mV Dropout at 100mA Load (165mV at
150mA load)
♦ Thermal-Overload and Short-Circuit Protection
♦ Reverse-Battery Protection
♦ 60dB PSRR at 100Hz
♦ 1µA max Shutdown Current
Ordering Information
Applications
PCS Phones
Modems
PART
TEMP. RANGE
PIN-PACKAGE
Cellular Phones
Hand-Held Instruments
MAX8885EUK25
-40°C to +85°C
5 SOT23-5
Cordless Phones
Palmtop Computers
PCMCIA Cards
Electronic Planners
MAX8885EUK27
MAX8885EUK30
MAX8885EUK33
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
5 SOT23-5
5 SOT23-5
5 SOT23-5
MAX8885EUK50
-40°C to +85°C
5 SOT23-5
Output Voltage Selector Guide
PART
VOUT (V)
TOP MARK
MAX8885EUK25
2.5
ADLE
MAX8885EUK27
MAX8885EUK30
MAX8885EUK33
2.7
3.0
3.3
ADLF
ADLG
ADLH
Note: See Output Voltage Selector Guide for more information.
MAX8885EUK50
5.0
ADLJ
Note: Other output voltages between 2.5V and 5.0V are available in 100mV increments—contact factory for information.
Minimum order quantity is 25,000 units.
Typical Operating Circuit
OUTPUT
PRESET
2.5V TO 5.0V
150mA
Pin Configuration
INPUT
+2.5V TO +6.5V
TOP VIEW
IN
IN 1
GND 2
5
COUT
4.7µF
CIN
1µF
OUT
MAX8885
MAX8885
100k
ON
OFF
SHDN 3
OUT
4
POK
POK
SHDN
TO
µC
GND
SOT23-5
________________________________________________________________ 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.
MAX8885
General Description
The MAX8885 low-dropout (LDO) linear regulator operates
from a +2.5V to +6.5V input voltage range and delivers up
to 150mA. It uses a P-channel MOSFET pass transistor to
allow a low 85µA supply current—which is independent of
the load—as well as LDO voltage. The MAX8885 is optimized to operate with low-cost, high-ESR output capacitors such as small case-size tantalum capacitors. It is ideal
for cost-sensitive portable equipment such as PCS and
cellular phones. For a pin-compatible, functionally equivalent device for use with a low-ESR, ceramic output capacitor, refer to the MAX8875 data sheet.
The MAX8885 features a power-OK output that indicates
when the output is out of regulation, and is available in
preset output voltage versions of 5.0V, 3.3V, 3.0V, 2.7V,
and 2.5V. Other features include 1µA (max) shutdown current, short-circuit protection, thermal shutdown protection,
and reverse-battery protection. The MAX8885 is available
in a miniature 5-pin SOT23 package.
MAX8885
150mA, Low-Dropout Linear Regulator
with Power-OK Output
ABSOLUTE MAXIMUM RATINGS
IN, SHDN, POK to GND...............................................-7V to +7V
SHDN to IN ...............................................................-7V to +0.3V
OUT to GND ................................................-0.3V to (VIN + 0.3V)
Output Short-Circuit Duration ........................................Indefinite
Continuous Power Dissipation (TA = +70°C)
5-Pin SOT23 (derate 7.1mW/°C above +70°C)..........571mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
θJA ..................................................................................140°C/W
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(NOMINAL) + 1V, SHDN = IN, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
Input Voltage
SYMBOL
CONDITIONS
MAX
UNITS
2.5
6.5
V
TA = +25°C, IOUT = 100µA
-1
1
TA = -40°C to +85°C, IOUT = 100µA
-2
2
TA = -40°C to +85°C,
IOUT = 100µA to 120mA
-3
2
VIN
Output Voltage Accuracy
MIN
Maximum Output Current
IOUT
150
Current Limit
ILIM
160
Ground Pin Current
IQ
TYP
%
mA
390
IOUT = 100µA
85
IOUT = 150mA
100
IOUT = 100µA
0.1
IOUT = 50mA
50
IOUT = 100mA
110
mA
180
µA
Dropout Voltage (Note 2)
VIN VOUT
Line Regulation
∆VLNR
VIN = (VOUT + 0.1V) to 6.5V, IOUT = 1mA
Load Regulation
∆VLDR
IOUT = 100µA to 120mA, COUT = 4.7µF
0.01
%/mA
COUT = 10µF, f = 10Hz to 100kHz
170
µVRMS
f = 100Hz
60
dB
Output Voltage AC PowerSupply Rejection Ratio
PSRR
mV
165
IOUT = 150mA
Output Voltage Noise
220
-0.15
0
0.15
%/V
SHUTDOWN
Shutdown Supply Current
SHDN Input Threshold
SHDN Input Bias Current
2
IOFF
VIH
VIL
I SHDN
SHDN = GND
TA = +25°C
0.005
TA = +85°C
0.02
2.0
VIN = 2.5V to 5.5V
V SHDN = 5.5V or GND
1
0.4
TA = +25°C
0
TA = +85°C
0.05
_______________________________________________________________________________________
100
µA
V
nA
150mA, Low-Dropout Linear Regulator
with Power-OK Output
MAX8885
ELECTRICAL CHARACTERISTICS (continued)
(VIN = VOUT(NOMINAL) + 1V, SHDN = IN, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
(1 - VOUT / VOUT(NOMINAL))100, VOUT falling,
IOUT = 0
-3
-5
-8
UNITS
POWER-OK OUTPUT
Power-OK Voltage Threshold
VPOK
1
Hysteresis, IOUT = 0
POK Output Voltage Low
VOL
ISINK = 1mA
0 ≤ VPOK ≤ 6.5V, VOUT in regulation
POK Output Leakage Current
%
-5.3
In dropout, VOUT falling
0.4
V
1
µA
THERMAL PROTECTION
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
TSHDN
170
°C
∆TSHDN
20
°C
Note 1: Limits are 100% production tested at TA = +25°C. Limits over the operating temperature range are guaranteed through correlation using Statistical Quality Control (SQC) methods.
Note 2: Dropout voltage is defined as VIN - VOUT, when VOUT is 100mV below the value of VOUT for VIN = VOUT + 0.5V.
Typical Operating Characteristics
(MAX8885EUK30, VIN = +3.6V, CIN = 1µF, COUT = 4.7µF, SHDN = IN, TA = +25°C, unless otherwise noted.)
GROUND PIN CURRENT vs.
OUTPUT LOAD
80
IOUT = 0
60
40
20
110
VIN = 5.0V
105
100
VIN = 3.5V
95
90
0
1
2
3
4
INPUT VOLTAGE (V)
5
6
VIN = VOUT(NOMINAL) + 0.5V
115
VOUT = 5.0V
MAX8885EUK50
110
105
100
VOUT = 3.0V
MAX8885EUK30
95
90
85
0
120
GROUND PIN CURRENT (µA)
100
115
MAX8885toc02
GROUND PIN CURRENT (µA)
IOUT = 150mA
GROUND PIN CURRENT (µA)
MAX8885toc01
120
GROUND PIN CURRENT vs.
OUTPUT LOAD
MAX8885toc03
GROUND PIN CURRENT
vs. INPUT VOLTAGE
85
0
15 30 45 60 75 90 105 120 135 150
OUTPUT LOAD (mA)
0
15 30 45 60 75 90 105 120 135 150
OUTPUT LOAD (mA)
_______________________________________________________________________________________
3
Typical Operating Characteristics (continued)
(MAX8885EUK30, VIN = +3.6V, CIN = 1µF, COUT = 4.7µF, SHDN = IN, TA = +25°C, unless otherwise noted.)
OUTPUT VOLTAGE vs.
INPUT VOLTAGE
90
VIN = 3.6V OR 5.0V
IOUT = 0
80
IOUT = 150mA
1.5
1.0
VIN = 3.6V
2.95
VIN = 5.0V
0
60
-15
10
35
60
2.90
0
85
1
2
3
4
5
TEMPERATURE (°C)
INPUT VOLTAGE (V)
OUTPUT VOLTAGE vs. TEMPERATURE
DROPOUT VOLTAGE vs.
OUTPUT LOAD
100
VIN = 3.6V
IOUT = 150mA
90
80
65
55
TA = +85°C
50
150
TA = +25°C
100
TA = -40°C
30
0
35
10
COUT = 10µF
40
25
60
-15
45
35
50
-40
ROUT = 60Ω
60
VIN = 5.0V
IOUT = 150mA
70
15 30 45 60 75 90 105 120 135 150
OUTPUT LOAD (mA)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
PSRR (dB)
VIN = 3.6V OR 5.0V
IOUT = 0
110
200
DROPOUT VOLTAGE (mV)
120
0
MAX8885toc08
250
MAX8885toc07
130
6
60
0
85
20
0.01
15 30 45 60 75 90 105 120 135 150
COUT = 1µF
0.1
OUTPUT LOAD (mA)
TEMPERATURE (°C)
OUTPUT NOISE SPECTRAL DENSITY
vs. FREQUENCY
10
100
1000
REGION OF STABLE COUT ESR vs.
LOAD CURRENT
OUTPUT NOISE (10Hz TO 100kHz)
1000
MAX8885toc11
MAX8885toc10
10
1
FREQUENCY (kHz)
MAX8885toc12
-40
COUT ESR (Ω)
100
1
VOUT
500µV/div
COUT = 1µF
10
STABLE REGION: COUT = 4.7µF TO 10µF
0.1
1
COUT = 10µF
0.01
COUT = 10µF
ILOAD = 50mA
IOUT = 50mA
0.1
1
10
FREQUENCY (kHz)
4
3.00
0.5
70
OUTPUT VOLTAGE (V)
2.0
3.05
MAX8885toc09
VIN = 3.6V
IOUT = 150mA
IOUT = 0
2.5
OUTPUT VOLTAGE (V)
110
100
3.0
3.10
MAX8885toc05
VIN = 5.0V
IOUT = 150mA
OUTPUT VOLTAGE (V)
GROUND PIN CURRENT (µA)
120
OUTPUT VOLTAGE vs. OUTPUT LOAD
3.5
MAX8885toc04
130
MAX8885toc06
GROUND PIN CURRENT
vs. TEMPERATURE
OUTPUT NOISE SPECTRAL DENSITY (µV/Hz)
MAX8885
150mA, Low-Dropout Linear Regulator
with Power-OK Output
100
1000
0.1
10ms/div
1
30
60
90
LOAD CURRENT (mA)
_______________________________________________________________________________________
120
150
150mA, Low-Dropout Linear Regulator
with Power-OK Output
LINE-TRANSIENT RESPONSE
LOAD-TRANSIENT RESPONSE
NEAR DROPOUT
LOAD-TRANSIENT RESPONSE
MAX8885toc13
MAX8885toc14
MAX8885toc15
50mA
5V
50mA
ILOAD
25mA/div
VIN
4V
0
0
VOUT
25mV/div
3.05V
3.02V
ILOAD
25mA/div
VOUT
VOUT
25mV/div
3.05V
3.00V
3.0V
2.98V
3.0V
VIN = VOUT + 0.5V
CIN = 1µF
ROUT = 60Ω
100µs/div
5µs/div
5µs/div
POK OUTPUT
SHUTDOWN DELAY
POK STARTUP RESPONSE
MAX8885toc17
MAX8885toc16
3V
VOUT
1V/div
0
0
0
2V
0
MAX8885toc18
5V
VOUT
2V/div
2.5V
VPOK
2V/div
2.5V
VIN
2.5V/div
0
VOUT
2.5V/div
0
5V
4V
VSHDN
1V/div
VIN = VOUT + 0.1V
CIN = 1µF
VIN
1V/div
3V
2.5V
VPOK
2.5V/div
0
2V
RLOAD = 60Ω
200µs/div
100µs/div
10ms/div
POK AND SHUTDOWN RESPONSE
MAX8885toc19
2V
VSHDN
0
2V
VOUT
0
4V
2V
VPOK
0
RLOAD = 60Ω
10µs/div
_______________________________________________________________________________________
5
MAX8885
Typical Operating Characteristics (continued)
(MAX8885EUK30, VIN = +3.6V, CIN = 1µF, COUT = 4.7µF, SHDN = IN, TA = +25°C, unless otherwise noted.)
150mA, Low-Dropout Linear Regulator
with Power-OK Output
MAX8885
Pin Description
PIN
NAME
FUNCTION
1
IN
Regulator Input. Supply voltage can range from +2.5V to +6.5V. Bypass with 1µF capacitor to GND
(see Capacitor Selection and Regulator Stability).
2
GND
Ground. This pin also functions as a heatsink. Solder to a large pad or the circuit-board ground
plane to maximize power dissipation.
3
SHDN
Active-Low Shutdown Input. A logic low reduces the supply current to below 1µA. Connect to IN
for normal operation.
4
POK
Power-OK Output. Active low, open-drain output indicates an out-of-regulation condition.
Connect a 100kΩ pull-up resistor to OUT for logic levels. If not used, leave this pin unconnected.
5
OUT
Regulator Output. Fixed 5.0V, 3.3V, 3.0V, 2.7V, or 2.5V output. Sources up to 150mA. Bypass
with 4.7µF (>0.5Ω typ ESR) tantalum capacitor to GND.
Detailed Description
The MAX8885 is a low-dropout, low-quiescent-current
linear regulator designed primarily for battery-powered
applications using low-cost, high-ESR tantalum capacitors. The device delivers up to 150mA and is available
with preset output voltages of 2.5V, 2.7V, 3.0V, 3.3V, or
5.0V. The MAX8885 consists of a 1.25V reference, error
amplifier, P-channel pass transistor, power-OK comparator, and internal feedback voltage divider (Figure 1).
The 1.25V bandgap reference is connected to the error
amplifier’s inverting input. The error amplifier compares
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
lower, which allows more current to pass to the output
and increases 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. The output
voltage is fed back through an internal resistor voltage
divider connected to the OUT pin.
Additional blocks include a current limiter, reverse-battery protection, thermal sensor, and shutdown logic.
Output Voltage
The MAX8885 is supplied with factory-set output voltages of 2.5V, 2.7V, 3.0V, 3.3V, or 5.0V. The part number’s two-digit suffix identifies the nominal output
voltage. For example, the MAX8885EUK33 indicates a
preset output voltage of 3.3V (see Output Voltage
Selector Guide).
Internal P-Channel Pass Transistor
The MAX8885 features a 1.1Ω (typ) P-channel MOSFET
pass transistor. This provides several advantages over
6
similar designs using PNP pass transistors, including
longer battery life. The P-channel MOSFET requires no
base drive, which reduces quiescent current significantly. PNP-based regulators waste considerable current in dropout when the pass transistor saturates. They
also use high base-drive currents under large loads.
The MAX8885 does not suffer from these problems and
consumes only 100µA of quiescent current whether in
dropout, light-load, or heavy-load applications (see
Typical Operating Characteristics).
Power-OK Output (POK)
When the output voltage goes out of regulation—as during dropout, current limit, or thermal shutdown—POK
goes low. POK is an open-drain N-channel MOSFET. To
obtain a logic-level output, connect a pull-up resistor
from POK to OUT. To minimize current consumption,
make this resistor as large as practical. A 100kΩ resistor works well for most applications. The POK function is
not active during shutdown. A capacitor to GND may be
added to generate a power-on-reset (POR) delay, which
can operate down to V IN ≤ 1V. (See POK Startup
Response in the Typical Operating Circuit.)
Current Limit
The MAX8885 includes a current limiter that monitors
and controls the pass transistor’s gate voltage, limiting
the output current to 390mA (typ). For design purposes, consider the current limit to be 160mA (min) to
600mA (max). The output can be shorted to ground for
an indefinite period of time without damaging the part.
Thermal-Overload Protection
When the junction temperature exceeds TJ = +170°C,
the thermal sensor signals the shutdown logic, turning
off the pass transistor and allowing the IC to cool. The
_______________________________________________________________________________________
150mA, Low-Dropout Linear Regulator
with Power-OK Output
SHDN
MAX8885
IN
REVERSE
BATTERY
PROTECTION
MOS DRIVER
WITH ILIMIT
ERROR
AMP
SHUTDOWN
LOGIC
P
OUT
MAX8885
POK
THERMAL
SENSOR
1.25V
REF
95%
REF
POK
GND
Figure 1. Functional Diagram
thermal sensor will turn the pass transistor on again
after the IC’s junction temperature cools by 20°C,
resulting in a pulsed output during continuous thermaloverload conditions.
Thermal-overload protection is designed to protect the
MAX8885 in the event of fault conditions. For continuous
operation, do not exceed the absolute maximum
junction-temperature rating of TJ = +150°C.
Operating Region and Power Dissipation
The MAX8885’s maximum power dissipation depends
on the thermal resistance of the case and circuit board,
the temperature difference between the die junction
and ambient air, and the rate of air flow. The power dissipation across the device is P = IOUT (VIN - VOUT). The
maximum power dissipation is:
PMAX = (TJ - TA) / ( θJB + θBA)
where TJ - TA is the temperature difference between the
MAX8885 die junction and the surrounding air; θJB (or
θJC) is the thermal resistance of the package; and θBA
is the thermal resistance through the printed circuit
board, copper traces, and other materials to the surrounding air.
The MAX8885’s GND pin performs the dual function of
providing an electrical connection to system ground
and channeling heat away. Connect GND to the system
ground using a large pad or ground plane.
Reverse-Battery Protection
The MAX8885 has a unique protection scheme that limits the reverse supply current to 1mA when either VIN or
V SHDN falls below ground. The circuitry monitors the
polarity of these two pins and disconnects the internal
circuitry and parasitic diodes when the battery is
reversed. This feature prevents device damage.
Applications Information
Capacitor Selection and
Regulator Stability
The MAX8885 is designed primarily for applications
using low-cost, high-ESR output capacitors such as
small case-size tantalum electrolytic capacitors. These
capacitors have ESR that can extend as high as 10Ω,
and their capacitance and ESR can vary widely over
their operating temperature range. For stable operation
over the full operating range, use a 4.7µF (1µF min)
capacitor with ESR > 0.5Ω (see the Region of Stable
C OUT ESR vs. Load Current graph in the Typical
Operating Characteristics). Ceramic output capacitors
should not be used with the MAX8885. For a pin-compatible, functionally equivalent linear regulator that is
suitable for ceramic output capacitors, refer to the
MAX8875 data sheet.
Bypass the MAX8885’s input with a 1µF or greater
capacitor to GND. Place this capacitor close to the
device (<5mm).
_______________________________________________________________________________________
7
PSRR and Operation from Sources
Other than Batteries
put capacitor is chosen to comply with the Region of
Stable COUT ESR vs. Load Current graph.
The MAX8885 is designed to allow low dropout voltages
and low quiescent currents in battery-powered systems.
Power-supply rejection is 60dB at low frequencies (see
the Power-Supply Rejection Ratio vs. Frequency graph
in the Typical Operating Characteristics).
Improve supply-noise rejection and transient response
by increasing the values of the input and output bypass
capacitors. The typical operating characteristics show
the MAX8885’s line- and load-transient responses.
A regulator’s minimum input-output voltage differential
(or dropout voltage) determines the lowest usable supply voltage. In battery-powered systems, this will determine the useful end-of-life battery voltage. Because the
MAX8885 uses a P-channel MOSFET pass transistor,
its dropout voltage is a function of drain-to-source onresistance (RDS(ON)) multiplied by the load current (see
Typical Operating Characteristics).
Load-Transient Considerations
The MAX8885’s load-transient response graphs (see
Typical Operating Characteristics) show three components of the output response. The first (and most significant) component is the abrupt drop in output voltage
due to the capacitor’s ESR. The magnitude of the voltage
drop is directly proportional to the output capacitor's
ESR and the size of the load transient and is independent of the regulator’s transient response. The second
component is the output voltage recovery, which is a
function of the regulator’s loop response and the capacitance at the output. The third component is a DC shift in
the output voltage resulting from the regulator’s finite output impedance. To improve the MAX8885’s load-transient response, increase the output capacitor’s value
and decrease its ESR. Take care to ensure that the out-
Dropout Voltage
VDROPOUT = VIN - VOUT = RDS(ON) · IOUT
Chip Information
TRANSISTOR COUNT: 266
Package Information
SOT5L.EPS
MAX8885
150mA, Low-Dropout Linear Regulator
with Power-OK Output
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.
8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 1999 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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