General Description
The MAX1589 low-dropout linear regulator operates
from a +1.62V to +3.6V supply and delivers a guaran-
teed 500mA continuous load current with a low 175mV
dropout. The high-accuracy (±0.5%) output voltage is
preset to internally trimmed voltages from +0.75V to
+3.0V. An active-low, open-drain reset output remains
asserted for at least 70ms after the output voltage reach-
es regulation. This device is offered in 6-pin thin SOT23
and 6-pin 3mm x 3mm thin DFN packages.
An internal PMOS pass transistor maintains low supply
current, independent of load and dropout voltage, making
the MAX1589 ideal for portable battery-powered equip-
ment such as personal digital assistants (PDAs), digital
still cameras, cell phones, cordless phones, and note-
book computers. Other features include logic-controlled
shutdown, short-circuit protection, and thermal-
overload protection.
Applications
Notebook Computers
Cellular and PCS Telephones
Personal Digital Assistants (PDAs)
Hand-Held Computers
Digital Still Cameras
PCMCIA Cards
CD and MP3 Players
Features
♦Low 1.62V Minimum Input Voltage
♦Guaranteed 500mA Output Current
♦±0.5% Initial Accuracy
♦Low 175mV Dropout at 500mA Load
♦70ms RESET Output Flag
♦Supply Current Independent of Load and Dropout
Voltage
♦Logic-Controlled Shutdown
♦Thermal-Overload and Short-Circuit Protection
♦Preset Output Voltages (0.75V, 1.0V, 1.2V, 1.3V,
1.5V, 1.8V, 2.5V, and 3.0V)
♦Tiny 6-Pin Thin SOT23 Package (<1.1mm High)
♦Thin 6-Pin TDFN Package (<0.8mm High)
MAX1589
Low-Input-Voltage, 500mA LDO Regulator
with
RREESSEETT
in SOT and TDFN
________________________________________________________________ Maxim Integrated Products 1
GND
OUTIN
TOP VIEW
MAX1589
SHDN
GND
THIN SOT23
I.C.
RESET
RESET
1
2
3
6
5
4
4
5
6
SHDN
IN
3
2
1
I.C.
OUT
TDFN
3mm x 3mm
MAX1589
Pin Configurations
ON
OFF
INPUT
1.62V TO 3.6V
IN
SHDN
GND
RESET
OUT
OUTPUT
0.75V TO 3.0V
500mA
TO μC
LOGIC
SUPPLY
100kΩ
MAX1589
CIN
1μF
COUT
4.7μF
Typical Operating Circuit
19-3048; Rev 2; 10/07
*Insert the desired three-digit suffix (see the Selector Guide) into
the blanks to complete the part number. Contact the factory for
other output voltages.
Selector Guide
TOP MARK
VOUT
(V) SUFFIX SOT TDFN
0.75 075 AAAT AFJ
1.00 100 AAAU AFK
1.20 120 — ATM
1.30 130 AAAV AFL
1.50 150 AAAW AFM
1.80 180 AAAX AFN
2.50 250 AAAY AFO
3.00 300 AAAZ AFP
Ordering Information
PART*
TEMP RANGE
PIN-PACKAGE
MAX1589EZT_ _ _-T -40°C to +85°C
6 Thin SOT23-6
MAX1589ETT_ _ _
-40°C to +85°C
6 TDFN
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.
MAX1589
Low-Input-Voltage, 500mA LDO Regulator
with
RREESSEETT
in SOT and TDFN
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
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.
IN, SHDN, RESET to GND .....................................-0.3V to +4.0V
OUT to GND ................................................-0.3V to (VIN + 0.3V)
Output Short-Circuit Duration.....................................Continuous
Continuous Power Dissipation (TA= +70°C)
6-Pin Thin SOT23 (derate 9.1mW/°C above +70°C)....727mW
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 Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
ELECTRICAL CHARACTERISTICS
(VIN = (VOUT + 0.5V) or VIN = 1.8V, whichever is greater; SHDN = IN, CIN = 1µF, COUT = 4.7µF, TA= -40°C to +85°C, unless other-
wise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
Input Voltage VIN
1.62 3.60
V
Input Undervoltage Lockout VUVLO VIN rising (180mV typical hysteresis)
1.30 1.60
V
IOUT = 150mA, TA = +25°C
-0.5 +0.5
Output Voltage Accuracy IOUT = 1mA to 500mA,
VIN = (VOUT + 0.5V) to +3.6V
-1.5 +1.5
%
Maximum Output Current IOUT Continuous
500
mARMS
Current Limit ILIM VOUT = 96% of nominal value
550 850 1150
mA
No load 70
140
IOUT = 500mA 90
Ground Current IQ
Dropout (Note 2) 70
µA
Dropout Voltage
VIN - VOUT
IOUT = 500mA, VOUT ≥ 1.8V (Note 2)
175 350
mV
Load Regulation ΔVLDR IOUT = 1mA to 500mA
0.02 0.5
%
Line Regulation ΔVLNR
VIN = (VOUT + 0.5V) to +3.6V, IOUT = 100mA -0.15 +0.01 +0.15
% / V
Output Noise 10Hz to 100kHz, IOUT = 10mA 86
µVRMS
PSRR f < 1kHz, IOUT = 10mA 70 dB
SHUTDOWN
TA = +25°C
0.001
1
Shutdown Supply Current IOFF SHDN = GND TA = +85°C
0.01
µA
VIH VIN = 1.62V to 3.6V
1.4
SHDN Input Logic Levels VIL VIN = 1.62V to 3.6V
0.6
V
TA = +25°C 1
300
SHDN Input Bias Current ISHDN V
S H DN
= 0 or 3.6V TA = +85°C 5 nA
Turn-On Delay From SHDN high to OUT high, VOUT = 1.5V 90 µs
RESET OUTPUT
Reset Threshold Accuracy VOUT falling (1.7% typical hysteresis) 80
82.5
85
%VOUT
I
RESET = 100µA
1.5 100
RESET Output Low Voltage VOL VIN = +1.0V, I
RESET = 100µA 3
100
mV
MAX1589
Low-Input-Voltage, 500mA LDO Regulator
with
RREESSEETT
in SOT and TDFN
_______________________________________________________________________________________ 3
Note 1: Limits are 100% production tested at TA= +25°C. Limits over the operating temperature range are guaranteed by design.
Note 2: The dropout voltage is defined as VIN - VOUT, when VOUT is 4% lower than the value of VOUT when VIN = VOUT + 0.5V.
ELECTRICAL CHARACTERISTICS (continued)
(VIN = (VOUT + 0.5V) or VIN = 1.8V, whichever is greater; SHDN = IN, CIN = 1µF, COUT = 4.7µF, TA= -40°C to +85°C, unless other-
wise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
TA = +25°C
0.001
1
RESET Output High
Leakage Current IOH V
RESET = 3.6V,
RESET not asserted TA = +85°C
0.01
µA
Reset Delay tRP From VOUT high to RESET rising 70
100 160
ms
THERMAL PROTECTION
Thermal-Shutdown Temperature T SHDN
+165
°C
Thermal-Shutdown Hysteresis
ΔT SHDN
15 °C
OUTPUT VOLTAGE ACCURACY
vs. LOAD CURRENT
MAX1589 toc01
LOAD CURRENT (mA)
OUTPUT VOLTAGE ACCURACY (%)
400300200100
-0.1
0
0.1
0.2
-0.2
0 500
VOUT = +3.0V
VOUT = +1.5V
VOUT = +0.75V
OUTPUT VOLTAGE ACCURACY
vs. TEMPERATURE
MAX1589 toc03
TEMPERATURE (°C)
OUTPUT VOLTAGE ACCURACY (%)
603510-15
-1.0
-0.5
0
0.5
1.0
1.5
-1.5
-40 85
VOUT = +1.5V
IOUT = 0mA, 100mA, 500mA
120
60
0.01 0.1 1 10 100 1000
GROUND-PIN CURRENT
vs. LOAD CURRENT
MAX1589 toc04
LOAD CURRENT (mA)
GROUND-PIN CURRENT (μA)
100
110
70
80
90
VOUT = +3.0V
VOUT = +1.5V
VOUT = +0.75V
GROUND-PIN CURRENT
vs. TEMPERATURE
MAX1589 toc06
TEMPERATURE (°C)
GROUND-PIN CURRENT (μA)
603510-15
60
70
80
90
100
50
-40 85
VOUT = +1.5V
IOUT = 1mA TO 500mA
IOUT = 0mA
Typical Operating Characteristics
(VIN = (VOUT + 0.5V) or 1.8V, whichever is greater; SHDN = IN, CIN = 1µF, COUT = 4.7µF, TA= +25°C, unless otherwise noted.)
MAX1589
Low-Input-Voltage, 500mA LDO Regulator
with
RREESSEETT
in SOT and TDFN
4 _______________________________________________________________________________________
DROPOUT VOLTAGE
vs. LOAD CURRENT
MAX1589 toc07
LOAD CURRENT (mA)
VDROPOUT (mV)
400300200100
40
80
120
160
200
0
0 500
VOUT = +1.8V
VOUT = +3.0V
Typical Operating Characteristics (continued)
(VIN = (VOUT + 0.5V) or 1.8V, whichever is greater; SHDN = IN, CIN = 1µF, COUT = 4.7µF, TA= +25°C, unless otherwise noted.)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
FREQUENCY (kHz)
PSRR (dB)
100101
10
20
30
40
50
60
70
80
0
0.1 1000
IOUT = 10mA
VOUT = +3.0V
VOUT = +1.5V
VOUT = +0.75V
LINE-TRANSIENT RESPONSE
MAX1589 toc09
40μs/div
3.5V
4V
1.5V
10mV/div
AC-COUPLED
500mV/div
VOUT
VIN
ILOAD = 100mA
VOUT = 1.5V
LINE-TRANSIENT RESPONSE
NEAR DROPOUT
MAX1589 toc10
40μs/div
1.8V
2.5V
1.5V
10mV/div
AC-COUPLED
500mV/div
VOUT
VIN
ILOAD = 100mA
VOUT = 1.5V
LOAD-TRANSIENT RESPONSE
MAX1589 toc12
20μs/div
100mA
500mA
50mV/div
AC-COUPLED
500mA/div
VOUT
IOUT
VIN = 3.6V
VOUT = 1.5V
LOAD-TRANSIENT RESPONSE
MAX1589 toc11
20μs/div
20mA
200mA
20mV/div
AC-COUPLED
200mA/div
VOUT
IOUT
VIN = 1.8V
VOUT = 1.5V
0
MAX1589
Low-Input-Voltage, 500mA LDO Regulator
with
RREESSEETT
in SOT and TDFN
_______________________________________________________________________________________ 5
SHUTDOWN RESPONSE
MAX1589 toc13
100μs/div
0
0
500mV/div
1V/div
VOUT
VSHDN
RL = 25Ω
VOUT = 1.5V
Typical Operating Characteristics (continued)
(VIN = (VOUT + 0.5V) or 1.8V, whichever is greater; SHDN = IN, CIN = 1µF, COUT = 4.7µF, TA= +25°C, unless otherwise noted.)
SHUTDOWN/RESET RESPONSE
MAX1589 toc14
40ms/div
0
0
0
1V/div
1V/div
1V/div
VRESET
VOUT
VSHDN
RL = 25Ω
VOUT = 1.5V
LINE/RESET RESPONSE
MAX1589 toc15
200ms/div
0
0
0
2V/div
1V/div
1V/div
VRESET
VOUT
VIN
RL = 25Ω
VOUT = 1.5V
MAX1589
Detailed Description
The MAX1589 is a low-dropout, low-quiescent-current,
high-accuracy linear regulator designed primarily for
battery-powered applications. The device supplies
loads up to 500mA and is available with preset output
voltages from +0.75V to +3.0V. As illustrated in Figure 1,
the MAX1589 contains a reference, an error amplifier, a
P-channel pass transistor, an internal feedback voltage-
divider, and a power-good comparator.
The error amplifier compares the 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, allowing more
current to pass to the output 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.
Internal P-Channel Pass Transistor
The MAX1589 features a 0.33Ω(RDS(ON)) P-channel
MOSFET pass transistor. Unlike similar designs using
PNP pass transistors, P-channel MOSFETs require no
base drive, which reduces quiescent current. PNP-
based regulators also waste considerable current in
dropout when the pass transistor saturates and use
high base-drive currents under large loads. The
MAX1589 does not suffer from these problems and
consumes only 90µA (typ) of quiescent current under
heavy loads, as well as in dropout.
Shutdown
Pull SHDN low to enter shutdown. During shutdown, the
output is disconnected from the input, an internal 1.5kΩ
resistor pulls OUT to GND, RESET is actively pulled
low, and supply current drops below 1µA.
RREESSEETT
Output
The MAX1589’s microprocessor (µP) supervisory cir-
cuitry asserts a guaranteed logic-low reset during
power-up, power-down, and brownout conditions down
to +1V. RESET asserts when VOUT is below the reset
threshold and remains asserted for at least 70ms (tRP)
after VOUT rises above the reset threshold.
Current Limit
The MAX1589 monitors and controls the pass transis-
tor’s gate voltage, limiting the output current to 850mA
(typ). If the output current exceeds ILIM, the MAX1589
output voltage drops.
Thermal-Overload Protection
Thermal-overload protection limits total power dissipa-
tion in the MAX1589. When the junction temperature
exceeds +165°C, a thermal sensor turns off the pass
Low-Input-Voltage, 500mA LDO Regulator
with
RREESSEETT
in SOT and TDFN
6 _______________________________________________________________________________________
PART
SOT23 TDFN
NAME FUNCTION
16IN
Regulator Input. Supply voltage can range from +1.62V to +3.6V. Bypass IN with at least a
1µF ceramic capacitor to GND (see the Capacitor Selection and Regulator Stability
section).
2 — GND Ground. GND also functions as a heatsink. Solder GND to a large pad or circuit-board
ground plane to maximize SOT23 power dissipation.
— 4 GND Ground
35SHDN Active-Low Shutdown Input. A logic low reduces supply current to below 1µA. Connect to
IN or logic high for normal operation.
43RESET
Active-Low, Open-Drain Reset Output. RESET rises 100ms after the output has achieved
regulation. RESET falls immediately if VOUT drops below 82.5% of its nominal voltage, or if
the MAX1589 is shut down.
5 2 I.C. Internally Connected. Leave floating or connect to GND.
6 1 OUT Regulator Output. Sources up to 500mA. Bypass with a 4.7µF low-ESR ceramic capacitor
to GND.
—Exposed
Pad EP Ground. EP also functions as a heatsink. Solder EP to a large pad or circuit-board ground
plane to maximize TDFN power dissipation.
Pin Description
transistor, allowing the IC to cool. The thermal sensor
turns the pass transistor on again after the junction tem-
perature cools by 15°C, resulting in a pulsed output
during continuous thermal-overload conditions.
Thermal-overload protection safeguards the MAX1589
in the event of fault conditions. For continuous opera-
tion, do not exceed the absolute maximum junction-
temperature rating of +150°C.
Operating Region and Power Dissipation
The MAX1589’s maximum power dissipation depends
on the thermal resistance of the IC package and circuit
board, the temperature difference between the die
junction and ambient air, and the rate of airflow. The
power dissipated in the device is P = IOUT ✕(VIN -
VOUT). The maximum allowed power dissipation is:
PMAX = (TJ(MAX) - TA) / (θJC + θCA)
where TJ(MAX) - TAis the temperature difference between
the MAX1589 die junction and the surrounding air, θJC is
the thermal resistance of the junction to the case, and
θCA is the thermal resistance from the case through the
PC board, copper traces, and other materials to the sur-
rounding air. Typical thermal resistance (θJC + θJA) for a
device mounted to a 1in square, 1oz copper pad is
41°C/W for the 3mm x 3mm TDFN package, and
110°C/W for the 6-pin thin SOT23 package. For best
heatsinking, expand the copper connected to GND, or
the exposed paddle.
The MAX1589 delivers up to 500mA and operates with
an input voltage up to +3.6V. However, when using the
6-pin SOT23 version, high output currents can only be
sustained when the input-output differential voltage is
low, as shown in Figure 2.
The maximum allowed power dissipation for the 6-pin
TDFN is 1.951W at TA= +70°C. Figure 3 shows that the
maximum input-output differential voltage is not limited
by the TDFN package power rating.
Applications Information
Capacitor Selection and
Regulator Stability
Capacitors are required at the MAX1589’s input and
output for stable operation over the full temperature
range and with load currents up to 500mA. Connect a
1µF ceramic capacitor between IN and GND and a
4.7µF low-ESR ceramic capacitor between OUT and
GND. The input capacitor (CIN) lowers the source
impedance of the input supply. Use larger output
MAX1589
Low-Input-Voltage, 500mA LDO Regulator
with
RREESSEETT
in SOT and TDFN
_______________________________________________________________________________________ 7
Figure 1. Functional Diagram
P
OUT
RESET
MAX1589
MOS DRIVER
WITH ILIMIT
ERROR
AMP
POWER-GOOD
COMPARATOR
THERMAL
SENSOR 100ms
TIMER
82.5%
REF
REF
SHUTDOWN
LOGIC
IN
SHDN
GND
MAX1589
capacitors to reduce noise and improve load-transient
response, stability, and power-supply rejection.
The output capacitor’s equivalent series resistance
(ESR) affects stability and output noise. Use output
capacitors with an ESR of 30mΩor less to ensure sta-
bility and optimize transient response. Surface-mount
ceramic capacitors have very low ESR and are com-
monly available in values up to 10µF. Connect CIN and
COUT as close to the MAX1589 as possible to minimize
the impact of PC board trace inductance.
Noise, PSRR, and Transient Response
The MAX1589 is designed to operate with low dropout
voltages and low quiescent currents in battery-powered
systems, while still maintaining good noise, transient
response, and AC rejection. See the Typical Operating
Characteristics for a plot of Power-Supply Rejection
Ratio (PSRR) vs. Frequency. When operating from noisy
sources, improved supply-noise rejection and transient
response can be achieved by increasing the values of
the input and output bypass capacitors and through
passive filtering techniques.
The MAX1589 load-transient response (see the Typical
Operating Characteristics) shows two components of
the output response: a near-zero DC shift from the out-
put impedance due to the load-current change, and the
transient response. A typical transient response for a
step change in the load current from 100mA to 500mA
is 35mV. Increasing the output capacitor’s value and
decreasing the ESR attenuates the overshoot.
Input-Output (Dropout) Voltage
A regulator’s minimum input-output voltage difference
(dropout voltage) determines the lowest usable supply
voltage. In battery-powered systems, this determines
the useful end-of-life battery voltage. Because the
MAX1589 uses a P-channel MOSFET pass transistor, its
dropout voltage is a function of drain-to-source on-resis-
tance (RDS(ON) = 0.33Ω) multiplied by the load current
(see the Typical Operating Characteristics):
VDROPOUT = VIN - VOUT = 0.33Ω✕IOUT
The MAX1589 ground current reduces to 70µA in dropout.
Chip Information
TRANSISTOR COUNT: 2556
PROCESS: BiCMOS
Low-Input-Voltage, 500mA LDO Regulator
with
RREESSEETT
in SOT and TDFN
8 _______________________________________________________________________________________
Figure 2. Power Operating Regions for 6-Pin SOT23: Maximum
Output Current vs. Input Voltage
MAXIMUM OUTPUT CURRENT
vs. INPUT VOLTAGE
(POWER DISSIPATION LIMIT)
(VIN - VOUT) (V)
MAXIMUM OUTPUT CURRENT (mA)
2.52.01.51.00.503.0
MAXIMUM RECOMMENDED
OUTPUT CURRENT 6-PIN SOT23
TA = +85°C
TA = +70°C
MAX1589 fig02
100
200
300
400
500
600
0
MAXIMUM OUTPUT CURRENT
vs. INPUT VOLTAGE
(POWER DISSIPATION LIMIT)
(VIN - VOUT) (V)
MAXIMUM OUTPUT CURRENT (mA)
2.52.01.51.00.503.0
MAXIMUM RECOMMENDED
OUTPUT CURRENT 6-PIN TDFN
TA = +85°C
MAX1589 fig03
100
200
300
400
500
600
0
Figure 3. Power Operating Region for 6-Pin TDFN: Maximum
Output Current vs. Input Voltage
MAX1589
Low-Input-Voltage, 500mA LDO Regulator
with
RREESSEETT
in SOT and TDFN
_______________________________________________________________________________________ 9
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
6L THIN SOT23.EPS
MAX1589
Low-Input-Voltage, 500mA LDO Regulator
with
RREESSEETT
in SOT and TDFN
10 ______________________________________________________________________________________
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
MAX1589
Low-Input-Voltage, 500mA LDO Regulator
with
RREESSEETT
in SOT and TDFN
______________________________________________________________________________________ 11
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
6, 8, &10L, DFN THIN.EPS
MAX1589
Low-Input-Voltage, 500mA LDO Regulator
with
RREESSEETT
in SOT and TDFN
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
© 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
COMMON DIMENSIONS
SYMBOL MIN. MAX.
A 0.70 0.80
D 2.90 3.10
E 2.90 3.10
A1 0.00 0.05
L 0.20 0.40
PKG. CODE N D2 E2 eJEDEC SPEC b[(N/2)-1] x e
PACKAGE VARIATIONS
0.25 MIN.k
A2 0.20 REF.
2.00 REF0.25±0.050.50 BSC2.30±0.1010T1033-1
2.40 REF0.20±0.05- - - - 0.40 BSC1.70±0.10 2.30±0.1014T1433-1
1.50±0.10 MO229 / WEED-3
0.40 BSC - - - - 0.20±0.05 2.40 REFT1433-2 14 2.30±0.101.70±0.10
T633-2 6 1.50±0.10 2.30±0.10 0.95 BSC MO229 / WEEA 0.40±0.05 1.90 REF
T833-2 8 1.50±0.10 2.30±0.10 0.65 BSC MO229 / WEEC 0.30±0.05 1.95 REF
T833-3 8 1.50±0.10 2.30±0.10 0.65 BSC MO229 / WEEC 0.30±0.05 1.95 REF
2.30±0.10 MO229 / WEED-3 2.00 REF0.25±0.050.50 BSC1.50±0.1010T1033-2
Revision History
Pages changed at Rev 2: 1, 8–12