Analog Devices Inc./Maxim Integrated MAX1976AEZT285+

Overview

MAX1976AEZT285+ from Maxim Integrated is a low-dropout linear regulator with integrated active-low open-drain RESET output, designed for battery-powered portable systems. It delivers 300mA continuous output current with ±0.5% output voltage accuracy, 100mV dropout at full load, and operates from 1.62V to 3.6V input. Its preset 2.85V output targets core voltage regulation in handheld computing and mobile communication devices.

For engineers reviewing the MAX1976AEZT285+ datasheet, MAX1976AEZT285+ pinout, MAX1976AEZT285+ application, or MAX1976AEZT285+ equivalent, key selection criteria include guaranteed 300mA load capability under low-input-voltage conditions (≥1.62V), 70ms RESET delay timing, thermal-overload protection, and compatibility with 1µF/4.7µF ceramic bypass capacitor network.

Technical Context

The MAX1976AEZT285+ employs an internal p-channel MOSFET pass transistor (R_DS(ON) = 0.33Ω) enabling supply current independence from load and dropout voltage. Its error amplifier compares a precision reference against internal feedback to regulate output, while a dedicated power-good comparator monitors V_OUT against 82.5% of nominal voltage to control the open-drain RESET signal.

RESET assertion occurs during power-up, brownout (down to VIN = +1V), and shutdown, with a guaranteed minimum delay of 70ms after V_OUT reaches regulation. Thermal shutdown activates at +165°C with 15°C hysteresis, and current limiting engages at ≥450mA to protect against overload.

Key Specifications

Pinout & Package

MAX1976AEZT285+ is packaged in a 6-pin thin SOT23-6 package (1.6mm × 2.9mm × 1.1mm height), optimized for space-constrained portable PCB layouts. The exposed pad is not present in this SOT23 variant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A05285PDBVR and NCP1117DT285T5G, MAX1976AEZT285+ uniquely balances 300mA drive, 100mV dropout, 70ms RESET, and SOT23-6 size-making it the only option meeting all four requirements simultaneously for space- and battery-limited designs.

Availability

MAX1976AEZT285+ is available at Aetrix Electronics and suitable for notebook computers, cellular phones, portable audio players, and PCMCIA cards requiring stable component supply with guaranteed 300mA output and precise 2.85V regulation.

Supply support for MAX1976AEZT285+ 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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.

The MAX1963A/MAX1976A product line was engineered specifically for low-input-voltage, high-accuracy LDO regulation in portable battery-powered equipment-emphasizing minimal dropout, tight DC accuracy, integrated power-good signaling, and compact packaging.

FAQ

What is the exact output voltage of MAX1976AEZT285+ and how is it set?

The MAX1976AEZT285+ has a factory-trimmed fixed output voltage of 2.85V. This value is laser-trimmed during wafer test and does not require external resistors or configuration pins. The suffix "285" in the part number explicitly denotes the 2.85V output, and electrical testing confirms ±0.5% accuracy at +25°C and ±2.5% over full temperature and load range. No user adjustment is possible or required for MAX1976AEZT285+.

Does MAX1976AEZT285+ support operation below 1.8V input?

Yes, MAX1976AEZT285+ is fully specified to operate from 1.62V to 3.6V input. Its BiCMOS process and p-channel MOSFET pass element enable stable regulation even as single-cell Li-ion batteries discharge below 2.0V. The device maintains 300mA output capability down to VIN = VOUT + 100mV = 2.95V, and continues regulating (at reduced current) as low as 1.62V input-critical for maximizing usable battery capacity in portable systems.

What is the function and timing behavior of the RESET pin on MAX1976AEZT285+?

The RESET pin on MAX1976AEZT285+ is an active-low, open-drain output that signals power-good status. It asserts low during power-up until VOUT reaches ≥82.5% of 2.85V (≥2.35V) and remains asserted for a guaranteed minimum of 70ms thereafter. It also pulls low immediately during brownout (VOUT falling below 2.35V) or SHDN activation. This 70ms delay is specific to the MAX1976A variant and distinguishes it from the 2.2ms delay in MAX1963A devices.

Can MAX1976AEZT285+ be used with ceramic output capacitors smaller than 4.7µF?

While MAX1976AEZT285+ is characterized and stabilized with a minimum 4.7µF low-ESR ceramic capacitor, operation with smaller values (e.g., 2.2µF) may be feasible in low-transient applications-but is not guaranteed across temperature and load. Reducing COUT increases output impedance, degrading load-transient response (observed overshoot >20mV for 20mA→200mA steps) and potentially compromising PSRR and stability margins. For production use, 4.7µF remains the validated minimum per the datasheet's capacitor selection guidelines for MAX1976AEZT285+.

How does thermal protection work in MAX1976AEZT285+ and what is its trip point?

MAX1976AEZT285+ incorporates thermal-overload protection that disables the pass transistor when junction temperature exceeds +165°C. Once tripped, the device remains off until the die cools by 15°C (to +150°C), at which point regulation resumes-creating a pulsed output under sustained overload. This hysteresis prevents thermal oscillation. The SOT23-6 package's thermal resistance (θ_JA) limits continuous 300mA operation to cases where (VIN − VOUT) × 300mA stays within 727mW derated above +70°C, directly impacting safe operating area for MAX1976AEZT285+.