Analog Devices Inc./Maxim Integrated MAX38908ATD+T

Overview

MAX38908ATD+T from Maxim Integrated is a 4A, high-PSRR nMOS LDO linear regulator with adjustable 0.6V–5.0V output, 0.9V–5.5V input range, and 2.7V–20V BIAS supply support-designed for FPGA core rails, server μPs, and portable cameras requiring tight ±1% DC accuracy and fast transient response under 4A load.

For engineers reviewing the MAX38908ATD+T datasheet, MAX38908ATD+T pinout, MAX38908ATD+T application, or MAX38908ATD+T equivalent, this page delivers verified package mapping (14-pin 3mm×3mm TDFN), confirmed feedback-based voltage programming, thermal shutdown at 165°C, 52dB IN PSRR at 10kHz, and reverse-current protection-key selection criteria for high-reliability power delivery in space-constrained embedded systems.

Technical Context

The MAX38908ATD+T uses an nMOS pass device architecture with separate BIAS rail to decouple gate drive from input supply, enabling stable operation across wide VIN (0.9V–5.5V) and VBIAS (2.7V–20V) ranges while maintaining low dropout (79mV typ at 4A, VOUT=1.2V, VBIAS=5V). Its feedback-controlled loop supports external resistor-divider programming and integrates active discharge, programmable soft-start via BYP capacitor, and monotonic startup.

Protection circuitry includes overcurrent limiting (4.4A–6.8A trip), thermal shutdown (165°C rising / 150°C falling), output-to-input reverse-current blocking (triggered at ~0.7A), and dual UVLO (VIN: 0.45V typ, VBIAS: 2.55V typ) with hysteresis-ensuring robustness during brownouts, short circuits, and power sequencing events in industrial and computing applications.

Key Specifications

Pinout & Package

MAX38908ATD+T is housed in a 14-pin, 3mm × 3mm TDFN package (package code T1433+2C) with exposed pad for thermal dissipation. The package supports JEDEC-standard reflow and achieves θJA = 41°C/W on a four-layer board.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A8300RGRT and NCP1117ST50T3G, the MAX38908ATD+T uniquely combines 4A capability, BIAS-rail independence for ultra-low dropout, ±1% accuracy over temperature, and integrated reverse-current blocking-making it optimal for next-generation compact, high-reliability power systems.

Availability

MAX38908ATD+T is available at Aetrix Electronics and suitable for FPGA core power delivery, server microprocessor rails, and portable camera sensor bias requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for MAX38908ATD+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) is a semiconductor leader specializing in high-performance analog, mixed-signal, and power management ICs for demanding industrial, computing, and communications applications.

The MAX38907/MAX38908 product line was designed specifically for high-current, low-noise, and thermally constrained power delivery in advanced digital systems-including FPGAs, μPs, and imaging sensors-where traditional LDOs fail to meet PSRR, accuracy, or protection requirements.

FAQ

What is the minimum output capacitance required for stability of the MAX38908ATD+T?

The MAX38908ATD+T is stable with a minimum 10μF ceramic output capacitor. The datasheet specifies 22μF as the recommended value for optimal transient response and PSRR performance. Using less than 10μF risks instability, especially under full 4A load, due to insufficient phase margin in the control loop. Always place the capacitor close to the OUT and GND pins with low-inductance layout.

Does the MAX38908ATD+T require a separate BIAS supply to operate?

Yes-the MAX38908ATD+T requires a valid BIAS supply between 2.7V and 20V applied to the BIAS pin. This rail powers the gate driver independently of the IN supply, enabling low dropout and stable regulation even when VIN approaches VOUT. Without BIAS, the device will not regulate; the BIAS voltage must also exceed the target VOUT by at least 2.0V for full specification compliance.

How does the POK (Power-OK) pin function on the MAX38908ATD+T?

The POK pin on the MAX38908ATD+T is an open-drain output that goes high when VOUT reaches 88–94% of its target voltage, indicating regulation. It requires an external 10–100kΩ pullup resistor to a logic-compatible supply. POK remains low during startup, dropout, or fault conditions-enabling precise power sequencing with FPGAs, μPs, or ASICs that monitor reset status before initialization.

Can the MAX38908ATD+T be used in parallel for higher current?

No-parallel operation of the MAX38908ATD+T is not supported or characterized. Its feedback architecture and lack of current-sharing features (e.g., current-sense outputs or master-slave sync) make unbalanced current distribution likely, risking thermal runaway or premature failure. For >4A needs, select a higher-current LDO or use a multiphase DC/DC solution instead.

What is the maximum allowable input-to-output voltage difference (headroom) for specified PSRR performance of the MAX38908ATD+T?

The MAX38908ATD+T delivers its specified 52dB IN PSRR at 10kHz only when the input-to-output headroom is maintained at 300mV. Below this, PSRR degrades significantly-e.g., at 150mV headroom, PSRR falls to ~42dB. Designers must ensure VIN ≥ VOUT + 0.3V during steady-state operation to meet noise-rejection requirements in sensitive analog or high-speed digital circuits.