Analog Devices Inc./Maxim Integrated MAX8556ETE/V+T

Overview

The MAX8556ETE/V+T from Maxim Integrated is a 4A ultra-low-input-voltage LDO regulator with p-channel MOSFET pass element, adjustable output (0.5V to VIN − 0.2V), 100mV typical dropout at 4A, ±1% output accuracy over load/line/temperature, and integrated Power-OK (POK) output. It operates from 1.425V–3.6V input and targets point-of-load regulation in high-density server and optical module power supplies.

For engineers reviewing the MAX8556ETE/V+T datasheet, MAX8556ETE/V+T pinout, MAX8556ETE/V+T application, or MAX8556ETE/V+T equivalent, key selection criteria include its 1.425V minimum input capability, POK fault signaling, thermal shutdown threshold (+160°C), 800μA typical ground current under full load, and compatibility with low-ESR ceramic output capacitors (≤50mΩ).

Technical Context

The MAX8556ETE/V+T uses an internal 25mΩ p-channel MOSFET pass transistor, eliminating charge-pump or external bias requirements and enabling stable operation down to 1.425V input. Its error amplifier regulates FB to 0.500V (±5mV) with <1µA input bias, supporting precise resistor-divider-based output programming.

Protection architecture includes foldback current limiting (7A typ current-limit threshold), thermal shutdown at +160°C (with +115°C hysteresis), and undervoltage lockout (1.35V typ enable threshold with 70mV hysteresis). The open-drain POK output asserts low when VOUT deviates >±10% or during thermal fault/shutdown.

Key Specifications

Pinout & Package

The MAX8556ETE/V+T is housed in a 16-pin TQFN package (5mm × 5mm) with exposed thermal paddle (EP), requiring solder connection to PCB ground plane for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with TPS7A8300RGRT and NCP1117ST50T3G, the MAX8556ETE/V+T uniquely combines 4A capability, 1.425V minimum input, POK signaling, and TQFN thermal performance-making it the only option for high-current, low-headroom, fault-aware point-of-load applications.

Availability

MAX8556ETE/V+T is available at Aetrix Electronics and suitable for server power delivery, optical transceiver biasing, 5G base station RF front-ends, and ATE load board applications requiring stable component supply, automotive-grade temperature range (-40°C to +85°C), and RoHS-compliant packaging.

Supply support for MAX8556ETE/V+T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated, now part of Analog Devices, designs precision analog, mixed-signal, and power management ICs for industrial, communications, and computing markets.

The MAX8556ETE/V+T belongs to Maxim's ultra-low-input-voltage LDO family, engineered specifically for high-current, low-headroom point-of-load regulation in space-constrained infrastructure equipment.

FAQ

What is the minimum input voltage supported by the MAX8556ETE/V+T?

The MAX8556ETE/V+T supports a minimum input voltage of 1.425V, verified across temperature and load conditions. This enables direct regulation from single-cell lithium batteries or low-voltage intermediate distribution buses. Operation below 1.425V is prohibited per absolute maximum ratings and triggers undervoltage lockout at ~1.35V (typ), ensuring reliable startup behavior. The MAX8556ETE/V+T maintains regulation and specified performance down to this limit without requiring external bias circuitry.

Does the MAX8556ETE/V+T include power-good signaling?

Yes, the MAX8556ETE/V+T features an open-drain Power-OK (POK) output that transitions high-impedance when the regulated output is within ±10% of its nominal value. POK pulls low during output fault, thermal shutdown, or when EN is low. It includes 50µs internal glitch immunity and requires an external pullup resistor to a logic supply ≤3.6V. This function is exclusive to the MAX8556 variant; the MAX8557 substitutes a POR output instead.

What thermal management is required for the MAX8556ETE/V+T at full 4A load?

At 4A and 1.425V input → 1.2V output, the MAX8556ETE/V+T dissipates ~1W. To maintain junction temperature ≤+150°C, the 16-pin TQFN package requires connection of its exposed paddle (EP) to a multilayer PCB ground plane using ≥9 thermal vias (12mil diameter, 1mil plating). Per JEDEC standards, this enables 2667mW dissipation at +70°C ambient. For higher ambient or sustained loads, increase copper area and thermal via count-failure to properly connect EP risks thermal shutdown at +160°C.

Can the MAX8556ETE/V+T be used with ceramic output capacitors?

Yes, the MAX8556ETE/V+T is explicitly designed for ceramic output capacitors with ESR ≤50mΩ. The datasheet specifies 2×10µF low-ESR ceramics on the output, and recommends 20–120µF total for optimal transient response. Unlike older LDOs requiring tantalum or aluminum electrolytics for stability, the MAX8556ETE/V+T's internal compensation is optimized for ceramic use-reducing board area, improving reliability, and enabling fast load-step response with ≤40mV overshoot.

How does the MAX8556ETE/V+T achieve low quiescent current under heavy load?

The MAX8556ETE/V+T achieves 800μA typical ground current independent of load due to its p-channel MOSFET pass transistor architecture. Unlike bipolar-based LDOs that require base drive current scaling with load, the pMOS device draws no gate current-quiescent current remains constant from zero to 4A. This design eliminates the efficiency penalty of traditional LDOs in dropout and enables predictable battery life estimation in portable infrastructure applications using the MAX8556ETE/V+T.