Maxim MAX8526EUD+ 1.425v to 3.6v input, 2a, 0.2v dropout ldo regulator Datasheet

19-3190; Rev 2; 8/09
KIT
ATION
EVALU
E
L
B
AVAILA
1.425V to 3.6V Input, 2A,
0.2V Dropout LDO Regulators
The MAX8526/MAX8527/MAX8528 low-dropout linear
regulators operate from input voltages as low as 1.425V
and are able to deliver up to 2A 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, 2.2µF ceramic input capacitors and 10µF ceramic output capacitors to deliver 2A
output current. High bandwidth provides excellent transient response and limits the output voltage deviation to
45mV for a 20mA to 2A load step, with only a 10µF
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 MAX8526/MAX8527/MAX8528 feature
low 500µA typical 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 MAX8527 features a power-OK (POK) output that
transitions high when the regulator output is within
±10% of its nominal output voltage. The MAX8528 features a 150ms power-on reset (POR) output.
The parts are packaged in a 14-pin TSSOP package,
which includes an exposed pad for optimal power
dissipation.
Applications
Servers
Networking
Features
o 1.425V to 3.6V Input Voltage Range
o Guaranteed 200mV Dropout at 2A Output Current
o ±0.6% Initial Accuracy
o ±1.4% Output Accuracy over
Load/Line/Temperature (0°C to +85°C)
o Compatible with Ceramic Capacitors
o Fast Transient Response
o 440µA Operating Supply Current
o <50µA Shutdown Supply Current
o Short-Circuit Protection
o Thermal-Overload Protection
o Soft-Start Limits Inrush Current
o 5mm x 6.4mm Footprint, 1.1mm Profile
Ordering Information
TEMP RANGE
PIN-PACKAGE
MAX8526EUD
PART
-40°C to +85°C
14 TSSOP
MAX8526EUD+
-40°C to +85°C
14 TSSOP
MAX8527EUD
-40°C to +85°C
14 TSSOP
MAX8527EUD+
-40°C to +85°C
14 TSSOP
MAX8527EUD/V+
-40°C to +85°C
14 TSSOP
MAX8528EUD
-40°C to +85°C
14 TSSOP
MAX8528EUD+
-40°C to +85°C
14 TSSOP
+Denotes a lead(Pb)-free RoHS-compliant package.
/V Denotes an automotive qualified part.
Storage
Typical Operating Circuit
Base Stations
Optical Modules
Post Regulators
INPUT
1.425V TO 3.6V
Notebooks
2.2µF
IN_
OUT_
MAX8526
MAX8527
MAX8528
PDAs
ATE
OUTPUT
0.5V TO (VIN - 0.2V), 2A
10µF
POWER-ON RESET
POR (MAX8528)
POWER-OK
FB
POK (MAX8527)
ON
Pin Configurations appear at end of data sheet.
EN
GND
OFF
________________________________________________________________ Maxim Integrated Products
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.
1
MAX8526/MAX8527/MAX8528
General Description
MAX8526/MAX8527/MAX8528
1.425V to 3.6V Input, 2A,
0.2V Dropout LDO Regulators
ABSOLUTE MAXIMUM RATINGS
IN, EN, POK (MAX8527), POR (MAX8528),
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 (TA = +70°C,
EP soldered to PC board ground)
14-Pin TSSOP (derate 20.8mW/°C above +70°C)..............1.7W
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
(Circuit of Figure 1: VIN = +1.8V, VOUT = +1.5V, EN = IN, IOUT = 2mA, TA = -40°C to +85°C, unless otherwise noted.) (Note 1)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
3.600
V
1.38
V
IN
Input Voltage Range
Input Undervoltage Lockout
1.425
VIN rising, 70mV hysteresis
1.32
1.35
OUT
Output Voltage Range
0.5
Load Regulation
IOUT = 2mA to 2A
Line Regulation
VIN = 1.425V to 3.6V, VOUT = 1.225V, IOUT = 2mA
Dropout Voltage (VIN - VOUT)
VIN = 1.425V, IOUT = 2A, VFB = 480mV
Current Limit
VIN = 3.6V, VOUT = 3V, VFB = 480mV
Output Shutdown Leakage
VIN = 3.6V, VOUT = 0V, VEN = 0V
3.4
0.08
-0.15
3.2
V
%/A
0
+0.15
%/V
100
200
mV
4
4.8
A
0.5
50
µA
500
503
FB
IOUT = 20mA, TA = +85°C
497
FB Threshold Accuracy
VOUT = 1.225V to 3V, VIN = (VOUT + 0.2V) to 3.6V,
IOUT = 2mA to 2A
493
FB Input Bias Current
VFB = 0.5V, VIN = 3.6V
2
507
0.001
_______________________________________________________________________________________
1
mV
µA
1.425V to 3.6V Input, 2A,
0.2V Dropout LDO Regulators
(Circuit of Figure 1: VIN = +1.8V, VOUT = +1.5V, EN = IN, IOUT = 2mA, TA = -40°C to +85°C, unless otherwise noted.) (Note 1)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
GND
GND Supply Current
GND Shutdown Current
VIN = 3.6V, VOUT = 3V, IOUT = 20mA
440
Dropout, VIN = 3.6V, VFB = 480mV
500
800
VIN = 3.6V, EN = GND
0.5
50
µA
µA
POK (MAX8527 Only)
Power-OK Threshold
VFB moving out of regulation,
VHYS = 10mV, IN = 1.425V to 3.6V
POK Output Voltage Low
VFB = 0.4V or 0.6V, IPOK = 2mA
POK Output Current High
VPOK = 3.6V
POK Fault Delay Time
From FB to POK
FB high
540
550
560
FB low
440
450
460
25
200
mV
mV
0.001
1
µA
25
50
100
µs
440
450
460
mV
25
200
mV
0.001
1
µA
150
210
ms
POR (MAX8528 Only)
Power-On Reset Threshold
VFB falling, VHYS = 10mV, VIN = 1.425V to 3.6V
POR Output Voltage Low
VFB = 0.4V or 0.6V, IPOR = 2mA
POR Output Current High
VPOR = 3.6V
POR Rising Delay Time
From FB to POR
105
EN
Enable Input Threshold
VIN = 1.425V to 3.6V
Enable Input Bias Current
VEN = 0 or 3.6V
EN rising
EN falling
1.2
0.4
-1
+1
V
µA
THERMAL SHUTDOWN
Thermal-Shutdown Threshold
Output on or off
TJ rising
+165
TJ falling
+150
°C
OUTPUT TRANSIENT
Load Transient
IOUT = 20mA to 2A to 20mA, tRISE = tFALL = 1µs
3
%
Line Transient
δVIN = 0.5V, tRISE = tFALL = 5µs
3
%
Note 1: Specifications to TA = -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.
_______________________________________________________________________________________
3
MAX8526/MAX8527/MAX8528
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics
(Typical values are: VIN = +1.8V, VOUT = +1.5V, IOUT = 2A, COUT =10µF, CIN = 2.2µF, and TA = +25°C, unless otherwise noted.)
OUTPUT VOLTAGE
vs. LOAD CURRENT
1.50
1.45
1.40
1.499
1.498
1.497
TA = +85°C
1.496
1.495
1.494
TA = +25°C
1.493
TA = -40°C
700
MAX8526/27/28 toc03
1.500
ILOAD = 2A
600
GROUND CURRENT (µA)
OUTPUT VOTAGE (V)
1.55
GROUND CURRENT
vs. INPUT VOLTAGE
MAX8526/27/28 toc02
TA = -40°C TO +85°C
OUTPUT VOLTAGE (V)
1.60
MAX8526/27/28 toc01
OUTPUT VOLTAGE
vs. INPUT VOLTAGE
500
400
ILOAD = 1A
300
ILOAD = 0A
200
1.492
1.35
100
1.491
1.490
1.30
1.2
1.8
2.4
3.0
400
800
1200
1600
2000
2400
0
0.6
1.2
1.8
2.4
3.0
INPUT VOLTAGE (V)
LOAD CURRENT (mA)
INPUT VOLTAGE (V)
GROUND CURRENT
vs. LOAD CURRENT
DROPOUT VOLTAGE
vs. LOAD CURRENT
LINE-TRANSIENT RESPONSE
(VIN = 1.8V TO 2.5V, IOUT = 2A)
MAX8526/27/28 toc04
650
600
550
TA = +85°C
500
450
TA = +25°C
400
0
0
3.6
TA = -40°C
350
100
VOUT
10mV/div
AC-COUPLED
75
50
VIN
500mV/div
AC-COUPLED
25
300
0
250
0
400
800
1200
1600
2000
2400
0
400
LOAD CURRENT (mA)
800
1200
1600
100µs/div
2000
LOAD CURRENT (mA)
LOAD-TRANSIENT RESPONSE
(ILOAD = 0.2A TO 2.2A; CIN = 220µF
ELECTROLYTIC CAP CLOSE TO IN)
SHUTDOWN RESPONSE
MAX8526/27/28 toc08
MAX8526/27/28 toc07
VOUT
1V/div
VOUT
50mV/div
AC-COUPLED
IIN
2A/div
2.2A
0.2A
ILOAD
1A/div
40µs/div
4
3.6
MAX8526/27/28 toc06
125
MAX8526/27/28 toc05
0.6
DROPOUT VOLTAGE (mV)
0
GROUND CURRENT (µA)
MAX8526/MAX8527/MAX8528
1.425V to 3.6V Input, 2A,
0.2V Dropout LDO Regulators
EN
2V/div
100µs/div
_______________________________________________________________________________________
1.425V to 3.6V Input, 2A,
0.2V Dropout LDO Regulators
FB VOLTAGE vs. TEMPERATURE
PSRR vs. FREQUENCY (MAX8526)
501
500
FB VOLTAGE (mV)
60
50
40
30
20
499
498
497
496
10
495
ILOAD = 100mA
ILOAD = 20mA
494
-10
0.1
1
10
100
-40
1000
-15
10
35
60
FREQUENCY (kHz)
TEMPERATURE (°C)
OUTPUT RIPPLE VOLTAGE
OVERCURRENT THRESHOLD
vs. TEMPERATURE
MAX8526/27/28 toc11
VOUT
1mV/div
AC-COUPLED
85
MAX8526/27/28 toc12
OVERCURRENT THRESHOLD (A)
4.0
3.9
3.8
3.7
3.6
3.5
-40
10µs/div
-15
10
35
60
85
1600
2000
TEMPERATURE (°C)
CASE TEMPERATURE
vs. LOAD CURRENT
SHORT-CIRCUIT CURRENT
MAX8526/27/28 TOC13
75
VOUT
1V/div
IOUT
2A/div
CASE TEMPERATURE (°C)
0.01
MAX8526/27/28 toc14
0
MAX8526/27/28 toc10
70
PSRR (dB)
502
MAX8526/27/28 toc09
80
60
45
30
15
VIN = 2.5V; TA = +25°C
0
40µs/div
0
400
800
1200
LOAD CURRENT (mA)
_______________________________________________________________________________________
5
MAX8526/MAX8527/MAX8528
Typical Operating Characteristics (continued)
(Typical values are: VIN = +1.8V, VOUT = +1.5V, IOUT = 2A, COUT =10µF, CIN = 2.2µF, and TA = +25°C, unless otherwise noted.)
1.425V to 3.6V Input, 2A,
0.2V Dropout LDO Regulators
MAX8526/MAX8527/MAX8528
Pin Description
PIN
NAME
FUNCTION
MAX8526
MAX8527
MAX8528
1
1
1
EN
Enable Input. Set low to place the device in low-current shutdown mode. Set
high for normal operation.
2–5
2–5
2–5
IN
Regulator Input. VIN can range from 1.425V to 3.6V. Bypass with a 2.2µF or
higher ceramic capacitor to GND.
6, 7, 14
7, 14
6, 14
T.P.
8
8
8
GND
9
9
9
FB
10–13
10–13
10–13
OUT
Regulator Output. Bypass with a 10µF ceramic capacitor to GND (a smaller
capacitor can be used if maximum load is less than 2A, i.e., COUT = IOUT (max)
x (1µF/200mA).
—
6
—
POK
Power-OK Output (MAX8527 Only). 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.
—
—
7
POR
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
Exposed Pad on the Underside of the Package. Solder to the ground plane for
proper heat dissipation.
—
Test Pin
Ground
Feedback Pin. Connect to output through a voltage-divider to set the output.
Functional Diagram
IN
THRESHOLD
OVERTHERMAL
PROTECTION
REF
EN
SHUTDOWN
LOGIC
0.50V
0.55V
0.45V
UNDERVOLTAGE
LOCKOUT
ERROR AMP
WITH
SOFT-START
MOS DRIVER
WITH ILIMIT
OUT
FB
MAX8526
MAX8527
MAX8528
POK
(MAX8527 ONLY)
POR
(MAX8528 ONLY)
GND
6
_______________________________________________________________________________________
1.425V to 3.6V Input, 2A,
0.2V Dropout LDO Regulators
The MAX8526/MAX8527/MAX8528 are low-input, lowdropout, PMOS regulators capable of delivering up to
2A 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 this
regulator has a PMOS output device, supply current is
not a significant function of load or input headroom.
Internal p-Channel Pass Transistor
The MAX8526/MAX8527/MAX8528 feature a 50mΩ
(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 MAX8526/
MAX8527/MAX8528 do not suffer from these problems
and consume only 500µA (typ) of quiescent current
under heavy loads, as well as in dropout.
Short-Circuit/Thermal Fault Protection
The MAX8526/MAX8527/MAX8528 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 4A. 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
TJ = +150°C.
ADJUSTABLE
OUTPUT
+1.425V TO +3.6V
IN
2.2µF
OUT
IN
IN
100kΩ*
IN
OUT
MAX8526
MAX8527
MAX8528
OUT
EN
SHUTDOWN
GND
where typically VFB = 0.5V. Choose R2 < 5kΩ to optimize quiescent current, accuracy, and high-frequency
power-supply rejection. To simplify resistor selection:
⎛V
⎞
R1 = R2 ⎜ OUT -1⎟
⎝ VFB
⎠
Soft-Start
Inherent soft-start limits inrush current. Peak inrush current is dependent on the value of COUT and can be
calculated as follows:
⎛ COUT (µF) ⎞
IINRUSH = ILOAD + ⎜
⎟
66
⎝
⎠
Shutdown Mode
The MAX8526/MAX8527/MAX8528 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 (POK, MAX8527 Only)
The MAX8527 features a power-OK 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/rises outside this
range, POK transitions low. This open-drain output
requires an external pullup resistor to IN. An internal
delay circuit prevents the 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 (POR, MAX8528 Only)
R2
The MAX8528 features a power-on reset output that
transitions high 150ms (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/thermal fault,
POR immediately transitions low.
10µF
FB
ENABLE
R1 ⎞
⎛
VOUT = VFB ⎜1 +
⎟
⎝
R2 ⎠
R1
OUT
POK (MAX8527) OR
POR (MAX8528)
Output Voltage Selection
The MAX8526/MAX8527/MAX8528 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:
*FOR MAX8527 AND MAX8528
Figure 1. Typical Application Circuit
_______________________________________________________________________________________
7
MAX8526/MAX8527/MAX8528
Detailed Description
MAX8526/MAX8527/MAX8528
1.425V to 3.6V Input, 2A,
0.2V Dropout LDO Regulators
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 = IOUT x (VIN - VOUT).
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 MAX8526/MAX8527/
MAX8528 inputs and outputs for stable operation over
the full temperature range and with load currents up to
2A. Connect a 2.2µF capacitor between IN and ground
and a 10µF capacitor with low equivalent-series-resistance (ESR) capacitor between OUT and ground for 2A
8
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 VIN sagging due to load transients. Smaller output capacitors can be used for output
currents less than 2A. Calculate COUT as follows:
COUT = IOUT(max) (1µF / 200mA)
Noise, PSRR, and Transient Response
The MAX8526/MAX8527/MAX8528 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 MAX8526/
MAX8527/MAX8528 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 2A is
45mV. Use larger output ceramic capacitors greater
than 10µF up to 100µF to attenuate the overshoot.
_______________________________________________________________________________________
1.425V to 3.6V Input, 2A,
0.2V Dropout LDO Regulators
TOP VIEW
EN 1
14 T.P.
EN 1
14 T.P.
EN 1
14 T.P.
IN
2
13 OUT
IN
2
13 OUT
IN
2
13 OUT
IN
3
12 OUT
IN
3
12 OUT
IN
3
12 OUT
11 OUT
IN 4
10 OUT
IN 5
IN 4
MAX8526
IN 5
MAX8527
11 OUT
IN 4
10 OUT
IN 5
MAX8528
11 OUT
10 OUT
T.P. 6
9
FB
POK 6
9
FB
T.P. 6
9
FB
T.P. 7
8
GND
T.P. 7
8
GND
POR 7
8
GND
TSSOP
TSSOP
TSSOP
Chip Information
TRANSISTOR COUNT: 2977
PROCESS: BiCMOS
Package Information
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in
the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status.
PACKAGE TYPE
PACKAGE CODE
DOCUMENT NO.
14 TSSOP
U14E-3
21-0108
_______________________________________________________________________________________
9
MAX8526/MAX8527/MAX8528
Pin Configurations
MAX8526/MAX8527/MAX8528
1.425V to 3.6V Input, 2A,
0.2V Dropout LDO Regulators
Revision History
REVISION
NUMBER
REVISION
DATE
0
2/04
Initial release
1
5/05
Added lead-free versions in the Ordering Information and updated the
Ordering Information and the Pin Description.
2
8/09
Added automotive version of the MAX8527.
DESCRIPTION
PAGES
CHANGED
—
1, 6, 8
1
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.
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