19-3190; Rev 1; 5/05 KIT ATION EVALU LE B A IL A AV 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 ♦ 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 (0°C to +85°C) ♦ Compatible with Ceramic Capacitors ♦ Fast Transient Response ♦ 440µA Operating Supply Current ♦ <50µA Shutdown Supply Current ♦ Short-Circuit Protection ♦ Thermal-Overload Protection ♦ Soft-Start Limits Inrush Current ♦ 5mm x 6.4mm Footprint, 1.1mm Profile Ordering Information PART TEMP RANGE PIN-PACKAGE MAX8526EUD -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 MAX8528EUD -40°C to +85°C 14 TSSOP MAX8528EUD+ -40°C to +85°C 14 TSSOP +Denotes lead-free packaging. Storage Typical Operating Circuit Base Stations Optical Modules Post Regulators INPUT 1.425V TO 3.6V Notebooks 2.2µF IN_ OUT_ OUTPUT 0.5V TO (VIN - 0.2V), 2A MAX8526 MAX8527 MAX8528 PDAs ATE 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/Dallas 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 = 0, VEN = 0 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 -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 DESCRIPTION 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. Test Pin 8 8 8 GND Ground 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. — Exposed Pad on the Underside of the Package. Solder to the ground plane for proper heat dissipation. Exposed Pad 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 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. Pin Configurations 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 11 OUT IN 4 IN 4 MAX8526 IN 5 10 OUT MAX8527 IN 5 10 OUT MAX8528 IN 5 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 8 _______________________________________________________________________________________ 1.425V to 3.6V Input, 2A, 0.2V Dropout LDO Regulators TSSOP 4.4mm BODY.EPS 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 © 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc. MAX8526/MAX8527/MAX8528 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.)