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MAX8556, MAX8557

4A Ultra-Low-Input-Voltage LDO Regulators

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Status Explanations for product status codes

Active: In Production.


The MAX8556/MAX8557 low-dropout linear regulators operate from input voltages as low as 1.425V and are able to deliver up to 4A of continuous output current with a typical dropout voltage of only 100mV. The output voltage is adjustable from 0.5V to VIN - 0.2V.

Designed with an internal p-channel MOSFET pass transistor, the MAX8556/MAX8557 maintain a low 800µA typical supply current, independent of the load current and dropout voltage. Using a p-channel MOSFET eliminates the need for an additional external supply or a noisy internal charge pump. Other features include a logic-controlled shutdown mode, built-in soft-start, short-circuit protection with foldback current limit, and thermal-overload protection. The MAX8556 features a POK output that transitions high when the regulator output is within ±10% of its nominal output voltage. The MAX8557 offers a power-on reset output that transitions high 140ms after the output has achieved 90% of its nominal output voltage.

The MAX8556/MAX8557 are available in a 16-pin thin QFN 5mm x 5mm package with exposed paddle.

Data Sheet

Download this datasheet in PDF formatDownload Rev 2 (PDF, 224kB)
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An evaluation board is available: MAX8556EVKIT

Key Features

  • 1.425V to 3.6V Input Voltage Range
  • Guaranteed 4A Output Current
  • ±1% Output Accuracy Over Load/Line/Temperature
  • 100mV Dropout at 4A Load (typ)
  • Built-In Soft-Start
  • 800µA (typ) Operating Supply Current
  • 150µA (max) Shutdown Supply Current
  • Short-Circuit Current Foldback Protection
  • Thermal-Overload Protection
  • ±10% Power-OK (MAX8556)
  • 140ms Power-On Reset Output (MAX8557)
  • Fast Transient Response
  • 16-Pin Thin QFN (5mm x 5mm) Package


  • Automated Test Equipment (ATE)
  • Networking
  • Optical Modules
  • Point-of-Load Supplies
  • Servers and Storage Devices
  • Wireless Base Stations

Key Specifications:

Linear Regulators
Part Number Regulators VIN
Low Batt./ Pwr. Fail Out POK/Reset Thresh.
Watchdog Reverse Batt. Protect. Oper. Temp.
min max min max typ max nom See Notes
MAX8556  1 1.4 3.6 0.5 3.4 0.1 4000 1600 No Vout-10% No No -40 to +85 $2.20 @1k
MAX8557  $3.91 @1k
See All Linear Regulators (149)

Pricing Notes:

This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.


MAX8556, MAX8557: Typical Operating Circuit
Typical Operating Circuit

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Information Index

Document Ref.: 19-3257 Rev 2; 2010-04-01
This page last modified: 2010-04-01