Analog Devices Inc./Maxim Integrated MAX38903BATB+T

Overview

MAX38903BATB+T from Analog Devices is a 1A, low-noise linear regulator in a 10-pin 3mm × 3mm TDFN package, delivering ±1% output accuracy over load/line/temperature, 5.5μVRMS output noise (10Hz–100kHz), and only 100mV dropout at full load. It supports resistor-programmable output voltage from 0.6V to 5.0V and includes active-high POK for reliable load startup in high-precision power rails.

For engineers reviewing the MAX38903BATB+T datasheet, MAX38903BATB+T pinout, MAX38903BATB+T application, or MAX38903BATB+T equivalent, key selection criteria include its 70dB PSRR at 10kHz, 800Ω active discharge, programmable soft-start via BYP capacitor, thermal/overcurrent protection, and compatibility with 4μF minimum output capacitance.

Technical Context

The MAX38903BATB+T implements a pMOS-based LDO architecture with internal 0.6V reference and precision error amplifier, enabling stable regulation across 1.7V–5.5V input while maintaining ultra-low noise performance. Its feedback loop uses external resistors (FB pin) to set output voltage, with bias current error minimized by limiting R2 ≤ 300kΩ.

It integrates multiple protection functions: reverse-current blocking triggered when VIN falls 10mV below VOUT, thermal shutdown at 165°C (hysteresis 15°C), and current limiting at 1.4A (typ). The POK signal asserts high after VOUT reaches 91% of regulation and deasserts during overload or shutdown.

Key Specifications

Pinout & Package

The MAX38903BATB+T is housed in a 10-pin, 3mm × 3mm TDFN package with exposed pad (EP) for thermal management. Pin 1 is OUT (top-left corner, pad-side down); EP must be soldered to a grounded thermal plane with ≥4 thermal vias.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A4701RGWR and LT3045EDD#PBF, the MAX38903BATB+T uniquely combines 1A capability, integrated POK, 800Ω active discharge, and 5.5μVRMS noise in a compact 10-pin TDFN - making it optimal for space-constrained, high-reliability systems requiring autonomous power sequencing and robust fault handling.

Availability

MAX38903BATB+T is available at Aetrix Electronics and suitable for communication infrastructure, high-fidelity audio equipment, and medical diagnostic devices requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for MAX38903BATB+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

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The MAX38903 family was designed specifically for noise-sensitive analog and RF power domains, emphasizing ultra-low output noise, precise DC accuracy, and integrated system-level features like POK and active discharge.

FAQ

What output voltage range does the MAX38903BATB+T support?

The MAX38903BATB+T supports resistor-programmable output voltages from 0.6V to 5.0V using an external feedback divider connected to the FB pin. The internal reference is 0.6V, and VOUT = 0.6V × (1 + R1/R2). For example, setting R1 = 950kΩ and R2 = 300kΩ yields 2.5V. This flexibility allows one MAX38903BATB+T variant to replace multiple fixed-output LDOs in a BOM.

Does the MAX38903BATB+T include power-good (POK) functionality?

Yes, the MAX38903BATB+T includes an active-high, open-drain POK output that asserts high when VOUT reaches 91% of its target regulation voltage. It deasserts during overcurrent, thermal shutdown, or EN disable. A pull-up resistor to a compatible supply (e.g., 3.3V or 5V) is required. This feature is absent in the MAX38903A/C/D variants and is specific to the MAX38903BATB+T.

How does the active discharge function work on the MAX38903BATB+T?

When the EN pin is pulled low, the MAX38903BATB+T internally connects an 800Ω resistor between the OUT pin and GND. This discharges output capacitors rapidly - reducing discharge time from >10ms to under 1ms with a 10μF capacitor. This behavior simplifies multi-rail power-down sequencing and prevents back-powering of upstream circuitry during system shutdown.

What is the minimum output capacitance required for stability with the MAX38903BATB+T?

The MAX38903BATB+T requires a minimum of 4μF total output capacitance at the OUT pin, including voltage and temperature derating. A 10μF X5R or X7R ceramic capacitor is recommended for robust performance. Lower values risk instability and poor transient response; the device remains stable with capacitances up to 100μF, provided ESR stays below 0.03Ω.

Can the MAX38903BATB+T operate with a 1.8V input supplying a 1.5V output?

Yes, the MAX38903BATB+T supports this configuration: its dropout voltage is ≤100mV at 1A, so 1.8V input can reliably regulate 1.5V output even under full load. At lighter loads, dropout drops further (e.g., 48mV typ at 1A with VIN = 3.6V). Input voltage must remain ≥1.7V, and VOUT must stay within 0.6V–5.0V - both satisfied in this case.