Analog Devices Inc./Maxim Integrated MAX1982EUT+T

Overview

MAX1982EUT+T from Maxim Integrated is a low-voltage, low-dropout linear regulator with external 5V bias supply input, delivering a fixed 1.2V ±3% output at up to 300mA from an input range of 1.25V to 5.5V. It features an open-drain PGOOD output with 1ms rising-edge propagation delay, thermal shutdown, and current limiting - designed specifically for VID power supplies in notebook computers and PDAs.

For engineers reviewing the MAX1982EUT+T datasheet, MAX1982EUT+T pinout, MAX1982EUT+T application, or MAX1982EUT+T equivalent, key selection criteria include its 1.2V fixed output accuracy, 175mV dropout at 150mA, 6-pin SOT23 package, external BIAS rail dependency, and PGOOD timing behavior under load transients and startup conditions.

Technical Context

The MAX1982EUT+T uses an internal N-channel pass transistor driven by a separate 4.5V–5.5V BIAS supply, decoupling gate drive from the low-voltage IN rail to enable regulation from inputs as low as 1.25V. Its control architecture integrates a 0.8V reference, error amplifier, current-sense circuitry, and UVLO monitoring on the BIAS rail (trip threshold 4.2V).

It implements fast transient response (10µs PGOOD fall time, 100µs startup to 90% VOUT), 65µVRMS output noise (10Hz–100kHz), and -60dB ripple rejection at 10kHz with 300mA load. Thermal shutdown activates at +160°C with 20°C hysteresis, and current limit ranges from 330mA to 1400mA depending on VIN–VOUT differential.

Key Specifications

Pinout & Package

Package: 6-pin SOT23-6 (U16-1), lead(Pb)-free/RoHS-compliant, top mark ABEA+.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-voltage LDO applications.

Compared with TPS79512DCQ and ADP1710AUJZ-1.2-R7, the MAX1982EUT+T uniquely supports 1.25V input via external BIAS, provides deterministic PGOOD timing, and maintains 300mA capability across extended temperature - making it irreplaceable in space-constrained, battery-critical VID systems.

Availability

MAX1982EUT+T is available at Aetrix Electronics and suitable for notebook computers, portable device power management, and low-voltage microcontroller supply applications requiring stable component supply, RoHS compliance, and long-term industrial availability.

Supply support for MAX1982EUT+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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, computing, and communications markets.

The MAX1982EUT+T belongs to Maxim's low-dropout linear regulator product line, engineered specifically for voltage identification (VID) power delivery in portable computing platforms where ultra-low input voltage operation and precise sequencing are mandatory.

FAQ

What is the minimum input voltage required for the MAX1982EUT+T to regulate 1.2V output?

The MAX1982EUT+T requires a minimum IN voltage of 1.25V to maintain 1.2V output under load, enabled by its external 5V BIAS supply driving the N-channel pass transistor gate. This architecture achieves lower effective dropout than single-supply LDOs - critical for single-cell Li-ion (2.7–4.2V) or partially discharged battery operation where input may dip below 1.3V. The BIAS rail must remain ≥4.5V for proper gate drive.

Does the MAX1982EUT+T require an external feedback resistor network?

No, the MAX1982EUT+T is a fixed-output regulator with internal feedback set to 1.2V; it does not use an ADJ pin or external resistors. Unlike the adjustable MAX1983 variant, the MAX1982EUT+T integrates the voltage divider internally - simplifying layout, reducing component count, and guaranteeing ±3% output accuracy across temperature and load without calibration.

How does the PGOOD signal behave during startup and fault conditions for the MAX1982EUT+T?

The MAX1982EUT+T PGOOD pin is an open-drain output that transitions high ≥1ms after VOUT reaches within 10% of 1.2V, providing a reliable power-good indication for system sequencers. It asserts low within 10µs if VOUT falls >120mV (10%) or during shutdown. A 100kΩ pull-up to BIAS is required for logic-level operation - ensuring compatibility with 3.3V or 5V interface logic without level-shifting.

Can the MAX1982EUT+T operate without the BIAS supply connected?

No - the MAX1982EUT+T will not regulate without a valid 4.5V–5.5V BIAS supply. The BIAS rail powers all internal circuitry including the reference, error amplifier, and gate driver. If BIAS is absent or below 3.8V (UVLO threshold), the device remains disabled and OUT floats. Connecting BIAS is mandatory; it cannot be omitted or tied to IN.

What thermal derating applies to the MAX1982EUT+T in a 6-pin SOT23 package?

The MAX1982EUT+T has a maximum continuous power dissipation of 696mW at +70°C ambient. Above +70°C, dissipation must be reduced by 8.7mW/°C - e.g., at +85°C ambient, max dissipation is 696mW − (15 × 8.7mW) = 565.5mW. This corresponds to ~470mA at 1.25V input (ΔV = 0.05V), confirming its 300mA rating is thermally sustainable across the full −40°C to +85°C operating range with standard PCB copper.