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19-3190; Rev 1; 5/05
KIT ATION EVALU E AILABL AV
1.425V to 3.6V Input, 2A, 0.2V Dropout LDO Regulators
General Description Features
1.425V to 3.6V Input Voltage Range Guaranteed 200mV Dropout at 2A Output Current 0.6% Initial Accuracy 1.4% Output Accuracy over Load/Line/Temperature (0C to +85C) Compatible with Ceramic Capacitors Fast Transient Response 440A Operating Supply Current <50A Shutdown Supply Current Short-Circuit Protection Thermal-Overload Protection Soft-Start Limits Inrush Current 5mm x 6.4mm Footprint, 1.1mm Profile
MAX8526/MAX8527/MAX8528
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 0C to +85C. These regulators use small, 2.2F ceramic input capacitors and 10F 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 10F 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 500A 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.
Ordering Information
PART MAX8526EUD MAX8526EUD+ MAX8527EUD MAX8527EUD+ MAX8528EUD MAX8528EUD+ TEMP RANGE -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C PIN-PACKAGE 14 TSSOP 14 TSSOP 14 TSSOP 14 TSSOP 14 TSSOP 14 TSSOP
Applications
Servers Networking Storage Base Stations Optical Modules Post Regulators Notebooks PDAs ATE
+Denotes lead-free packaging.
Typical Operating Circuit
INPUT 1.425V TO 3.6V IN_ 2.2F OUT_ OUTPUT 0.5V TO (VIN - 0.2V), 2A
MAX8526 MAX8527 MAX8528
POWER-ON RESET POR (MAX8528) POWER-OK ON POK (MAX8527) EN OFF GND FB
10F
Pin Configurations appear at end of data sheet.
________________________________________________________________ Maxim Integrated Products
1
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.
1.425V to 3.6V Input, 2A, 0.2V Dropout LDO Regulators MAX8526/MAX8527/MAX8528
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 = +70C, EP soldered to PC board ground) 14-Pin TSSOP (derate 20.8mW/C above +70C)..............1.7W Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
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 = -40C to +85C, unless otherwise noted.) (Note 1)
PARAMETER IN Input Voltage Range Input Undervoltage Lockout OUT Output Voltage Range Load Regulation Line Regulation Dropout Voltage (VIN - VOUT) Current Limit Output Shutdown Leakage FB IOUT = 20mA, TA = +85C FB Threshold Accuracy FB Input Bias Current VOUT = 1.225V to 3V, VIN = (VOUT + 0.2V) to 3.6V, IOUT = 2mA to 2A VFB = 0.5V, VIN = 3.6V 497 493 0.001 500 503 507 1 mV A IOUT = 2mA to 2A VIN = 1.425V to 3.6V, VOUT = 1.225V, IOUT = 2mA VIN = 1.425V, IOUT = 2A, VFB = 480mV VIN = 3.6V, VOUT = 3V, VFB = 480mV VIN = 3.6V, VOUT = 0, VEN = 0 3.2 -0.15 0.5 0.08 0 100 4 0.5 +0.15 200 4.8 50 3.4 V %/A %/V mV A A VIN rising, 70mV hysteresis 1.425 1.32 1.35 3.600 1.38 V V CONDITIONS MIN TYP MAX UNITS
2
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1.425V to 3.6V Input, 2A, 0.2V Dropout LDO Regulators
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1: VIN = +1.8V, VOUT = +1.5V, EN = IN, IOUT = 2mA, TA = -40C to +85C, unless otherwise noted.) (Note 1)
PARAMETER GND GND Supply Current GND Shutdown Current POK (MAX8527 only) Power-OK Threshold POK Output Voltage Low POK Output Current High POK Fault Delay Time POR (MAX8528 only) Power-On Reset Threshold POR Output Voltage Low POR Output Current High POR Rising Delay Time EN Enable Input Threshold Enable Input Bias Current THERMAL SHUTDOWN Thermal-Shutdown Threshold OUTPUT TRANSIENT Load Transient Line Transient IOUT = 20mA to 2A to 20mA, tRISE = tFALL = 1s VIN = 0.5V, tRISE = tFALL = 5s 3 3 % % Output on or off TJ rising TJ falling +165 +150 C VIN = 1.425V to 3.6V VEN = 0 or 3.6V EN rising EN falling 0.4 -1 +1 1.2 V A VFB falling, VHYS = 10mV, VIN = 1.425V to 3.6V VFB = 0.4V or 0.6V, IPOR = 2mA VPOR = 3.6V From FB to POR 105 440 450 25 0.001 150 460 200 1 210 mV mV A ms VFB moving out of regulation, VHYS = 10mV, IN = 1.425V to 3.6V VFB = 0.4V or 0.6V, IPOK = 2mA VPOK = 3.6V From FB to POK 25 FB high FB low 540 440 550 450 25 0.001 50 560 460 200 1 100 mV mV A s VIN = 3.6V, VOUT = 3V, IOUT = 20mA Dropout, VIN = 3.6V, VFB = 480mV VIN = 3.6V, EN = GND 440 500 0.5 800 50 A A CONDITIONS MIN TYP MAX UNITS
MAX8526/MAX8527/MAX8528
Note 1: Specifications to -40C 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
1.425V to 3.6V Input, 2A, 0.2V Dropout LDO Regulators MAX8526/MAX8527/MAX8528
Typical Operating Characteristics
(Typical values are: VIN = +1.8V, VOUT = +1.5V, IOUT = 2A, COUT =10F, CIN = 2.2F, and TA = +25C, unless otherwise noted.)
OUTPUT VOLTAGE vs. INPUT VOLTAGE
MAX8526/27/28 toc01
OUTPUT VOLTAGE vs. LOAD CURRENT
MAX8526/27/28 toc02
GROUND CURRENT vs. INPUT VOLTAGE
ILOAD = 2A 600 GROUND CURRENT (A) 500 400 300 200 100 0 ILOAD = 0A ILOAD = 1A
MAX8526/27/28 toc03
1.60 1.55 OUTPUT VOTAGE (V) 1.50 1.45 1.40 1.35 1.30 0 0.6 1.2 1.8
1.500 1.499 1.498 OUTPUT VOLTAGE (V) 1.497 1.496 1.495 1.494 1.493 1.492 1.491 1.490 TA = +25C TA = -40C TA = +85C
TA = -40C TO +85C
700
2.4
3.0
3.6
0
400
800
1200
1600
2000
2400
0
0.6
1.2
1.8
2.4
3.0
3.6
INPUT VOLTAGE (V)
LOAD CURRENT (mA)
INPUT VOLTAGE (V)
GROUND CURRENT vs. LOAD CURRENT
MAX8526/27/28 toc04
DROPOUT VOLTAGE vs. LOAD CURRENT
MAX8526/27/28 toc05
LINE-TRANSIENT RESPONSE (VIN = 1.8V TO 2.5V, IOUT = 2A)
650 600 GROUND CURRENT (A) 550 TA = +85C 500 450 400 350 300 250 0 400 800 1200 1600 2000 TA = +25C TA = -40C
125
MAX8526/27/28 toc06
DROPOUT VOLTAGE (mV)
100
75
VOUT 10mV/div AC-COUPLED
50
25
VIN 500mV/div AC-COUPLED
0 2400 0 400 800 1200 1600 2000 100s/div LOAD CURRENT (mA) LOAD CURRENT (mA)
LOAD-TRANSIENT RESPONSE (ILOAD = 0.2A TO 2.2A; CIN = 220F ELECTROLYTIC CAP CLOSE TO IN)
MAX8526/27/28 toc07
SHUTDOWN RESPONSE
MAX8526/27/28 toc08
VOUT 50mV/div AC-COUPLED 2.2A
VOUT 1V/div IIN 2A/div
0.2A
ILOAD 1A/div
EN 2V/div 100s/div
40s/div
4
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1.425V to 3.6V Input, 2A, 0.2V Dropout LDO Regulators
Typical Operating Characteristics (continued)
(Typical values are: VIN = +1.8V, VOUT = +1.5V, IOUT = 2A, COUT =10F, CIN = 2.2F, and TA = +25C, unless otherwise noted.)
FB VOLTAGE vs. TEMPERATURE
MAX8526/27/28 toc09
MAX8526/MAX8527/MAX8528
PSRR vs. FREQUENCY (MAX8526)
80 70 60 50 PSRR (dB) 40 30 20 10 0 -10 0.01 0.1 1 10 100 1000 FREQUENCY (kHz) ILOAD = 100mA 502 501 500 FB VOLTAGE (mV) 499 498 497 496 495 494 -40
ILOAD = 20mA -15 10 35 60 85
TEMPERATURE (C)
OUTPUT RIPPLE VOLTAGE
MAX8526/27/28 toc11
OVERCURRENT THRESHOLD vs. TEMPERATURE
MAX8526/27/28 toc12
4.0 OVERCURRENT THRESHOLD (A)
3.9
VOUT 1mV/div AC-COUPLED
3.8
3.7
3.6
3.5 10s/div -40 -15 10 35 60 85 TEMPERATURE (C)
SHORT-CIRCUIT CURRENT
MAX8526/27/28 TOC13
CASE TEMPERATURE vs. LOAD CURRENT
MAX8526/27/28 toc14
75
CASE TEMPERATURE (C)
VOUT 1V/div
60
45
30
IOUT 2A/div
15 VIN = 2.5V; TA = +25C 0
40s/div
0
400
800
1200
1600
2000
LOAD CURRENT (mA)
_______________________________________________________________________________________
MAX8526/27/28 toc10
5
1.425V to 3.6V Input, 2A, 0.2V Dropout LDO Regulators MAX8526/MAX8527/MAX8528
Pin Description
PIN MAX8526 1 2-5 6, 7, 14 8 9 10-13 MAX8527 1 2-5 7, 14 8 9 10-13 MAX8528 1 2-5 6, 14 8 9 10-13 NAME EN IN T.P. GND FB OUT DESCRIPTION Enable Input. Set low to place the device in low-current shutdown mode. Set high for normal operation. Regulator Input. VIN can range from 1.425V to 3.6V. Bypass with a 2.2F or higher ceramic capacitor to GND. Test Pin Ground Feedback Pin. Connect to output through a voltage-divider to set the output. Regulator Output. Bypass with a 10F ceramic capacitor to GND (a smaller capacitor can be used if maximum load is less than 2A, i.e., COUT = IOUT (max) x (1F/200mA). 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. 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. Exposed Pad on the Underside of the Package. Solder to the ground plane for proper heat dissipation.
--
6
--
POK
--
--
7
POR
Exposed Pad
--
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
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1.425V to 3.6V Input, 2A, 0.2V Dropout LDO Regulators
Detailed Description
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.
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: R1 VOUT = VFB 1 + R2 where typically VFB = 0.5V. Choose R2 < 5k to optimize quiescent current, accuracy, and high-frequency power-supply rejection. To simplify resistor selection: V R1 = R2 OUT -1 VFB
MAX8526/MAX8527/MAX8528
Internal P-Channel Pass Transistor
The MAX8526/MAX8527/MAX8528 feature a 50m (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 500A (typ) of quiescent current under heavy loads, as well as in dropout.
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 (F) IINRUSH = ILOAD + 66
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 +165C, the thermal-overload circuitry turns off the output, allowing the part to cool down. When the junction temperature cools to +150C, 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 = +150C.
ADJUSTABLE OUTPUT IN 2.2F IN IN 100k* IN OUT OUT
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 10k 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 50s (typ) after the trip threshold is initially reached. If the part is in shutdown mode, POK is low.
+1.425V TO +3.6V
MAX8526 MAX8527 MAX8528
OUT OUT FB
R1 10F
Power-On Reset (POR, MAX8528 Only)
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.
POK (MAX8527) OR POR (MAX8528) ENABLE EN SHUTDOWN *FOR MAX8527 AND MAX8528 GND
R2
Figure 1. Typical Application Circuit _______________________________________________________________________________________ 7
1.425V to 3.6V Input, 2A, 0.2V Dropout LDO Regulators MAX8526/MAX8527/MAX8528
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. 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) (1F / 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 10F up to 100F to attenuate the overshoot.
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 2.2F capacitor between IN and ground and a 10F capacitor with low equivalent-series-resistance (ESR) capacitor between OUT and ground for 2A
Pin Configurations
TOP VIEW
EN 1 IN IN 2 3 14 T.P. 13 OUT 12 OUT EN 1 IN IN 2 3 14 T.P. 13 OUT 12 OUT EN 1 IN IN 2 3 14 T.P. 13 OUT 12 OUT
IN 4 IN 5 T.P. 6 T.P. 7
MAX8526
11 OUT 10 OUT 9 8 FB GND
IN 4 IN 5 POK 6 T.P. 7
MAX8527
11 OUT 10 OUT 9 8 FB GND
IN 4 IN 5 T.P. 6 POR 7
MAX8528
11 OUT 10 OUT 9 8 FB GND
TSSOP
TSSOP
TSSOP
Chip Information
TRANSISTOR COUNT: 2977 PROCESS: BiCMOS
8
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1.425V to 3.6V Input, 2A, 0.2V Dropout LDO Regulators
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.)
TSSOP 4.4mm BODY.EPS
MAX8526/MAX8527/MAX8528
XX XX
PACKAGE OUTLINE, TSSOP, 4.40 MM BODY, EXPOSED PAD
21-0108
E
1
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 9 (c) 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.

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