4A Ultra-Low-Input-Voltage LDO Regulators

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.

Applications

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

* 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