The MAX8556/MAX8557 are low-dropout linear regulators that can operate from input voltages as low as 1.425V and 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. These regulators use an internal p-channel MOSFET pass transistor, resulting in a low supply current of 800µA typical, independent of the load current and dropout voltage. The use of a p-channel MOSFET eliminates the need for an additional external supply or a noisy internal charge pump. Additional features include 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.
The MAX8556 and MAX8557 are low‑dropout linear regulators that operate from input voltages as low as 1.425 V and can deliver up to 4 A of continuous output current. They feature a p‑channel MOSFET pass transistor, low quiescent current, and built‑in protection such as short‑circuit foldback and thermal overload.
The devices include a Power‑OK (POK) output on the MAX8556 and a Power‑On Reset (POR) output on the MAX8557, both open‑drain signals for system monitoring. They are supplied in a 16‑pin thin QFN package (5 mm × 5 mm) and are intended for server, networking, base‑station, and point‑of‑load applications.
| Input Voltage Range | 1.425 V to 3.6 V |
|---|---|
| Output Voltage Range | 0.5 V to 3.4 V |
| Maximum Output Current | 4 A continuous |
| Typical Dropout Voltage (4 A load) | 100 mV |
| Shutdown Supply Current (max) | 150 pA |
| Power‑OK Output (POK) | High when output within +10 % of nominal |
| Power‑On Reset Output (POR) | High 140 ms after output reaches 90 % of nominal |
| Package | 16‑Pin Thin QFN 5 mm × 5 mm |
| Operating Temperature Range | -40 °C to +85 °C |
The regulators operate from 1.425 V up to 3.6 V input.
They can provide up to 4 A of continuous output current.
Typical dropout is about 100 mV when delivering 4 A.
Both devices are offered in a 16‑pin thin QFN package measuring 5 mm × 5 mm.