General Description
The MAX8516/MAX8517/MAX8518 low-dropout linear
regulators operate from input voltages as low as 1.425V
and are able to deliver up to 1A of continuous output
current with a maximum dropout voltage of only 200mV.
The output voltage can be set from 0.5V to (VIN- 0.2V)
and is 1.4% accurate over load and line variations, from
0°C to +85°C.
These regulators use small, 1µF ceramic input capacitors and 4.7µF ceramic output capacitors to deliver 1A
output current. High bandwidth provides excellent transient response and limits the output voltage deviation to
45mV for a 20mA to 1A load step, with only a 4.7µF
ceramic output capacitor, and the voltage deviations can
be reduced further by increasing the output capacitor.
Designed with an internal p-channel MOSFET pass
transistor, the MAX8516/MAX8517/MAX8518 feature
low 340µA (typ) supply current during dropout conditions. Soft-start reduces inrush current. Other features
include a logic-controlled shutdown mode, short-circuit
protection, and thermal-overload protection.
The MAX8517 features a power-OK (POK) output that
transitions high when the regulator output is within
±10% of its nominal output voltage. The MAX8518
features a 150ms power-on reset output.
The parts are packaged in a 10-pin µMAX®package that
includes an exposed pad for optimal power dispation.
Applications
Servers
Storage
Networking
Base Stations
Optical Modules
Features
♦ 1.425V to 3.6V Input Voltage Range
♦ Guaranteed 200mV Dropout at 1A Output Current
♦ ±1.4% Output Accuracy Over Load, Line, and
Temperature (0°C to +85°C), ±0.6% Initial Accuracy
♦ Compatible with Ceramic Capacitors
♦ Fast Transient Response
♦ 320µA Operating Supply Current
♦ <25µA Shutdown Supply Current
♦ Short-Circuit Protection
♦ Thermal-Overload Protection
♦ Soft-Start Limits Inrush Current
MAX8516/MAX8517/MAX8518
1.425V to 3.6V Input, 1A,
0.2V Dropout LDO Regulators
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-3188; Rev 1; 4/04
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
EVALUATION KIT
AVAILABLE
PART TEMP RANGE PIN-PACKAGE
MAX8516EUB -40°C to +85°C 10 µMAX
MAX8517EUB -40°C to +85°C 10 µMAX
MAX8518EUB -40°C to +85°C 10 µMAX
1
2
3
4
5
10
9
8
7
6
N.C.
OUT
OUT
FBN.C.
IN
IN
EN
MAX8516
µMAX
TOP VIEW
GNDN.C.
1
2
3
4
5
10
9
8
7
6
N.C.
OUT
OUT
FBPOK
IN
IN
EN
MAX8517
µMAX
GNDN.C.
1
2
3
4
5
10
9
8
7
6
N.C.
OUT
OUT
FBN.C.
IN
IN
EN
MAX8518
µMAX
GNDPOR
Pin Configurations
MAX8516
MAX8517
MAX8518
1µF
4.7µF
INPUT
1.425V TO 3.6V
OUTPUT
0.5V TO (V
IN
- 0.2V), 1A
POWER-ON RESET
POWER-OK
ON
OFF
IN_
POR (MAX8518)
POK (MAX8517)
EN GND
FB
OUT_
Typical Operating Circuit
Post Regulators
Notebooks
PDAs
ATE
1
0
µ
M
A
X
3
m
m
x
5
m
m
µMAX is a registered trademark of Maxim Integrated Products, Inc.
MAX8516/MAX8517/MAX8518
1.425V to 3.6V Input, 1A,
0.2V Dropout LDO Regulators
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1. VIN= +1.8V, V
OUT
= +1.5V, EN = IN, I
OUT
= 1mA, TA = -40°C to +85°C, unless otherwise noted.) (Note 1)
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, EN, POK (MAX8517), POR (MAX8518),
FB to GND.........................................................-0.3V to +4.0V
OUT to GND..................................................-0.3V to (IN + 0.3V)
Output Short-Circuit Duration.....................................Continuous
Continuous Power Dissipation
(T
A
= +70°C, EP soldered to PC board ground)
10-Pin µMAX (derate 10.3mW/°C above +70°C).........824mW
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
PARAMETER CONDITIONS
UNITS
IN
Input Voltage Range
V
Input Undervoltage Lockout VIN rising, 70mV hysteresis
V
OUT
Output Voltage Range 0.5 3.4 V
Load Regulation I
OUT
= 1mA to 1A 0.1 %/A
Line Regulation VIN = 1.425V to 3.6V, V
OUT
= 1.225V, I
OUT
= 1mA
0
% / V
Dropout Voltage (VIN - V
OUT
)VIN = 1.425V, I
OUT
= 1A, VFB = 480mV
200 mV
Current Limit VIN = 3.6V, V
OUT
= 3V, V
FB
= 480mV 1.6 2 2.4 A
Output Shutdown Leakage VIN = 3.6V, V
OUT
= 0, VEN = 0
25 µA
FB
I
OUT
= 10mA, TA = +85°C
503
FB Threshold Accuracy
V
OUT
= 1.225V to 3V, VIN = V
OUT
+ 0.2V to 3.6V,
I
OUT
= 1mA to 1A
507
mV
FB Input Bias Current VFB = 0.5V, VIN = 3.6V
1µA
GND
VIN = 3.6V, V
OUT
= 3V, I
OUT
= 100mA
GND Supply Current
Dropout, V
IN
= 3.6V, VFB = 480mV
600
µA
GND Shutdown Current VIN = 3.6V, EN = GND
25 µA
POK (MAX8517 ONLY)
FB high
560
POK Threshold
V
FB
moving out of regulation,
V
HYS
= 10mV, IN = 1.425V to 3.6V
FB low
460
mV
POK Output Voltage Low V
FB
= 0.4V or 0.6V, I
POK
= 1mA 25 200 mV
POK Output Current High V
POK
= 3.6V
1µA
POK Fault Delay Time From FB to POK 25 50 100 µs
MIN TYP MAX
1.425 3.600
1.32 1.35 1.38
-0.15
100
0.25
497 500
493
540 550
440 450
0.001
320
340
0.25
0.001
+0.15
MAX8516/MAX8517/MAX8518
1.425V to 3.6V Input, 1A,
0.2V Dropout LDO Regulators
_______________________________________________________________________________________ 3
Note 1: Specifications to -40°C are guaranteed by design, not production tested.
Note 2: Measurements at high current are pulse tested, such that the junction temperature is ambient temperature. Minimum supply
voltage for output accuracy must be at least 1.425V.
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1. VIN= +1.8V, V
OUT
= +1.5V, EN = IN, I
OUT
= 1mA, TA = -40°C to +85°C, unless otherwise noted.) (Note 1)
PARAMETER CONDITIONS
UNITS
POR (MAX8518 ONLY)
POR Reset Threshold VFB falling, V
HYS
= 10mV, VIN = 1.425V to 3.6V
460 mV
POR Output Voltage Low V
FB
= 0.4V or 0.6V, I
POR
= 1mA 25 200 mV
POR Output Current High V
POR
= 3.6V
1µA
POR Rising Delay Time From FB to POR
210 ms
EN
EN rising 1.2
Enable Input Threshold VIN = 1.425V to 3.6V
EN falling 0.4
V
Enable Input Bias Current VEN = 0 or 3.6V -1 +1 µA
THERMAL SHUTDOWN
TJ rising
Thermal-Shutdown Threshold Output on or off
T
J
falling
°C
OUTPUT TRANSIENT
Load Transient I
OUT
= 20mA to 1A to 20mA, t
RISE
= t
FALL
= 1µs 3 %
Line Transient δV
IN
= 0.5V, t
RISE
= t
FALL
= 5µs 3 %
Typical Operating Characteristics
(Circuit of Figure 1, V
IN
= +1.8V, V
OUT
= +1.5V, I
OUT
= 1A, C
OUT
= 4.7µF, CIN= 1µF, TA= +25°C.)
OUTPUT VOLTAGE
vs. INPUT VOLTAGE
MAX8516/17/18 toc01
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
3.02.41.81.20.6
1.35
1.40
1.45
1.50
1.55
1.60
1.30
03.6
TA = -40°C TO +85°C
OUTPUT VOLTAGE
vs. LOAD CURRENT
MAX8516/17/18 toc02
LOAD CURRENT (mA)
OUTPUT VOLTAGE (V)
800600400200
1.492
1.494
1.496
1.498
1.500
1.502
1.490
0 1000 1200
TA = +85°C
TA = +25°C
TA = -40°C
GROUND CURRENT
vs. INPUT VOLTAGE
MAX8516/17/18 toc03
INPUT VOLTAGE (V)
GROUND CURRENT (µA)
3.02.40.6 1.2 1.8
100
200
300
400
500
0
03.6
I
LOAD
= 1A
I
LOAD
= 0.5A
I
LOAD
= 0A
MIN TYP MAX
440 450
0.001
105 150
+165
+150
MAX8516/MAX8517/MAX8518
1.425V to 3.6V Input, 1A,
0.2V Dropout LDO Regulators
4 _______________________________________________________________________________________
GROUND CURRENT
vs. LOAD CURRENT
MAX8516/17/18 toc04
LOAD CURRENT (mA)
GROUND CURRENT (µA)
1000800600400200
275
300
325
350
375
250
0 1200
TA = +25°C
TA = -40°C
TA = +85°C
DROPOUT VOLTAGE
vs. LOAD CURRENT
MAX8516/17/18 toc05
LOAD CURRENT (mA)
DROPOUT VOLTAGE (mV)
800600400200
25
50
75
100
125
0
0 1000
LINE INPUT TRANSIENT
(V
IN
= +1.8V TO +2.5V, I
LOAD
= 1A)
MAX8516/17/18 toc06
100µs/div
V
OUT
AC-COUPLED
20mV/div
V
IN
AC-COUPLED
0.5V/div
LOAD-TRANSIENT RESPONSE
(I
LOAD
= 0.1A TO 1A)
MAX8516/17/18 toc07
40µs/div
V
OUT
AC-COUPLED
50mV/div
I
LOAD
1A/div
CIN = 220µF ELECTROLYTIC
CAP CLOSE TO IN
PSRR vs. FREQUENCY (MAX8516)
MAX8516/17/18 toc09
FREQUENCY (kHz)
PSRR (dB)
1001010.1
10
20
30
40
50
60
70
80
0
0.01 1000
I
LOAD
= 100mA
SHUTDOWN RESPONSE
MAX8516/17/18 toc08
100µs/div
V
OUT
1V/div
EN
2V/div
I
IN
1A/div
Typical Operating Characteristics (continued)
(Circuit of Figure 1, V
IN
= +1.8V, V
OUT
= +1.5V, I
OUT
= 1A, C
OUT
= 4.7µF, CIN= 1µF, TA= +25°C.)
MAX8516/MAX8517/MAX8518
1.425V to 3.6V Input, 1A,
0.2V Dropout LDO Regulators
_______________________________________________________________________________________ 5
FB VOLTAGE vs. TEMPERATURE
MAX8516/17/18 toc10
TEMPERATURE (°C)
FB VOLTAGE (mV)
603510-15
499
500
501
502
498
-40 85
I
LOAD
= 10mA
OUTPUT RIPPLE VOLTAGE
MAX8516/17/18 toc11
100µs/div
V
OUT
AC-COUPLED
1mV/div
OVERCURRENT THRESHOLD
vs. TEMPERATURE
MAX8516/17/18 toc12
TEMPERATURE (°C)
OVERCURRENT THRESHOLD (A)
603510-15
1.80
1.85
1.90
1.95
1.75
-40 85
SHORT-CIRCUIT CURRENT
MAX8516/17/18 toc13
100µs/div
V
OUT
1V/div
I
OUT
2A/div
CASE TEMPERATURE
vs. LOAD CURRENT
MAX8516/17/18 toc14
LOAD CURRENT (mA)
CASE TEMPERATURE (°C)
800600400200
15
30
45
60
75
0
0 1000
VIN = 2.5V; TA = +25°C
Typical Operating Characteristics (continued)
(Circuit of Figure 1, V
IN
= +1.8V, V
OUT
= +1.5V, I
OUT
= 1A, C
OUT
= 4.7µF, CIN= 1µF, TA= +25°C.)
MAX8516/MAX8517/MAX8518
1.425V to 3.6V Input, 1A,
0.2V Dropout LDO Regulators
6 _______________________________________________________________________________________
Pin Description
PIN
MAX8516
NAME DESCRIPTION
111EN
Enable Input. Set low to place the device in low-current shutdown mode. Set
high for normal operation.
2, 3 2, 3 2, 3 IN
Regulator Input. V
IN
can range from +1.425V to +3.6V. Bypass with a 1µF or
higher ceramic capacitor to GND.
4, 5, 10 5, 10 4, 10 N.C.
No Connection. Pin 10 is internally pulled down to GND with a 10kΩ resistor.
Leave floating.
6 6 6 GND Ground
7 7 7 FB Feedback Pin. Connect to output through a voltage-divider to set the output.
8, 9 8, 9 8, 9 OUT
Regulator Output. Bypass with a 4.7µF ceramic capacitor to GND (a smaller
capacitor can be used if maximum load is less than 1A, i.e., C
OUT
= I
OUT
(max) ✕ (1µF/200mA).
—4—POK
Power-OK Output (MAX8517 Only). Open-drain output. Connect to a positive
supply with a pullup resistor. If not used, leave pin unconnected. See the
Detailed Description.
——5POR
Power-On Reset Output. Open-drain output. Connect to a positive supply with
a pullup resistor. If not used, leave pin unconnected (see the Detailed
Description for more details).
EP GND
Exposed Pad on the Underside of the Package. Solder to the ground plane for
proper heat dissipation.
Functional Diagram
MAX8517 MAX8518
IN
THRESHOLD
OVERTHERMAL
PROTECTION
EN
OVERTHERMAL
PROTECTION
MAX8516
MAX8517
MAX8518
GND
0.50V
0.55V
REF
0.45V
UNDERVOLTAGE
LOCKOUT
ERROR AMP
WITH
SOFT-START
MOS DRIVER
WITH I
LIMIT
OUT
FB
POK
(MAX8517 ONLY)
POR
(MAX8518 ONLY)
Detailed Description
The MAX8516/MAX8517/MAX8518 are low-input, lowdropout, PMOS regulators capable of delivering up to
1A of output current with as little as 200mV of headroom
from input to output. The PMOS output stage can be driven from input voltages down to +1.425V without sacrificing stability or transient performance. Since these
regulators have a PMOS output device, supply current
is not a significant function of load or input headroom.
Internal P-Channel Pass Transistor
The MAX8516/MAX8517/MAX8518 feature a 100mΩ (typ)
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 MAX8516/
MAX8517/MAX8518 do not suffer from these problems
and consume only 340µA (typ) of quiescent current
under heavy loads, as well as in dropout.
Short-Circuit/Thermal Fault Protection
The MAX8516/MAX8517/MAX8518 are fully protected
from a short circuit at the output through current-limiting
and thermal-overload circuitry. In the fault condition
when the output is shorted to ground, the output current
is limited to 2A. Under these conditions, the part quickly
heats up. When the junction temperature reaches
+165°C, the thermal-overload circuitry turns off the
output, allowing the part to cool down. When the junction
temperature cools to +150°C, the output turns back on
and tries to reestablish regulation. Current limiting and
thermal protection continue until the fault is removed. For
continuous operation, do not exceed the absolute maximum junction-temperature rating of T
J
= +150°C.
Output Voltage Selection
The MAX8516/MAX8517/MAX8518 feature an
adjustable output voltage from 0.5V to 3.4V, using two
external resistors connected as a voltage-divider to FB
as shown in Figure 1. The output voltage is set by the
following equation:
where typically V
FB
= 0.5V. Choose R2 ≤ 5kΩ to optimize quiescent current, accuracy, and high-frequency
power-supply rejection. To simplify resistor selection:
Soft-Start
Inherent soft-start limits inrush current. Peak inrush current is dependent on the value of C
OUT
and can be cal-
culated as follows:
Shutdown Mode
The MAX8516/MAX8517/MAX8518 include an enable
input. To shut down the device, pull EN to GND. For
normal operation, connect the EN to IN. During shutdown, an internal 10kΩ resistor pulls down the output.
Power-OK (MAX8517 Only)
The MAX8517 features a power-OK (POK) output to
indicate the status of the output. POK remains high
when the regulator output is within ±10% of its nominal
output voltage. If the output voltage falls or rises outside this range, POK transitions low. This open-drain
output requires an external pullup resistor to IN. An
internal delay circuit prevents POK from switching for
50µs (typ) after the trip threshold is initially reached. If
the part is in shutdown mode, POK is low.
Power-On Reset (MAX8518 Only)
The MAX8518 features a power-on reset (POR) output
that transitions high 140ms (typ) after the output has
risen above 90% of its final value. This open-drain output requires an external pullup resistor to IN. If the part
is in shutdown mode, falls below 90% of the nominal
output voltage, or experiences a short-circuit or thermal
fault, POR immediately transitions low.
II
CF
INRUSH LOAD
OUT
()
=+
µ
⎛
⎝
⎜
⎞
⎠
⎟
66
RR
V
V
OUT
FB
12 1 =
⎛
⎝
⎜
⎞
⎠
⎟
−
VV
R
R
OUT FB
=+
⎛
⎝
⎜
⎞
⎠
⎟
1
1
2
MAX8516/MAX8517/MAX8518
1.425V to 3.6V Input, 1A,
0.2V Dropout LDO Regulators
_______________________________________________________________________________________ 7
MAX8516
MAX8517
MAX8518
1µF
4.7µF
ENABLE
SHUTDOWN
IN
IN
POK (MAX8517) OR
POR (MAX8518)
EN GND
FB
OUT
OUT
100kΩ*
R1
R2
ADJUSTABLE
OUTPUT
*FOR MAX8517 AND MAX8518
+1.425V TO +3.6V
Figure 1. Typical Application Circuit
MAX8516/MAX8517/MAX8518
Operating Region and Power Dissipation
The 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 = I
OUT
✕ (V
IN
- V
OUT
).
The package features an exposed thermal pad on its
underside. This pad lowers the thermal resistance of
the package by providing a direct heat conduction
path from the die to the PC board.
Additionally, the ground pins (GND) perform the dual
function of providing an electrical connection to system
ground and channeling heat away. Connect the
exposed backside pad and GND to the system ground
using a large pad or ground plane, or multiple vias to
the ground plane layer.
Applications Information
Capacitor Selection and
Regulator Stability
Capacitors are required at the MAX8516/MAX8517/
MAX8518 inputs and outputs for stable operation over the
full temperature range and with load currents up to 1A.
Connect a 1µF capacitor between IN and ground and a
4.7µF capacitor with low equivalent series resistance
(ESR) between OUT and ground for 1A output current.
The input capacitor (CIN) lowers the source impedance of
the input supply. If input-supply source impedance is
high, place a larger input capacitor close to IN to prevent
VINsagging due to load transients. Smaller output capacitors can be used for output currents less than 1A.
Calculate C
OUT
as follows:
Noise, PSRR, and Transient Response
The MAX8516/MAX8517/MAX8518 are designed to
operate with low dropout voltages and low quiescent
currents 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 MAX8516/
MAX8517/MAX8518 load-transient response graphs
(see the Typical Operating Characteristics) show two
components of the output response: a DC shift from the
output impedance due to the load current change, and
the transient response. A typical transient overshoot for
a step change in the load current from 20mA to 1A is
45mV. Use larger output ceramic capacitors greater
than 4.7µF up to 50µF to attenuate the overshoot.
Chip Information
TRANSISTOR COUNT: 2849
PROCESS: BiCMOS
CI FmA
OUT OUT MAX
( / )
()
=×µ1 200
1.425V to 3.6V Input, 1A,
0.2V Dropout LDO Regulators
8 _______________________________________________________________________________________
MAX8516/MAX8517/MAX8518
1.425V to 3.6V Input, 1A,
0.2V Dropout LDO Regulators
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 9
© 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
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
.)
10L UMAX, EXPPADS.EPS
C
1
1
21-0109
PACKAGE OUTLINE, 10L uMAX, EXPOSED PAD
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