Analog Devices Inc./Maxim Integrated MAX603ESA+T

Overview

MAX603ESA+T from Maxim Integrated is a 5V fixed-output, low-dropout linear regulator with P-channel MOSFET pass transistor, delivering up to 500mA output current, 320mV dropout at 5V/500mA, and 15μA typical quiescent current. It operates from 2.7V to 11.5V input and features shutdown mode (2μA), reverse-current protection, and thermal overload protection - designed for battery-powered instrumentation and portable electronics.

For engineers reviewing the MAX603ESA+T datasheet, MAX603ESA+T pinout, MAX603ESA+T application, or MAX603ESA+T equivalent, key selection criteria include dropout voltage under load, quiescent current stability across temperature, shutdown threshold behavior vs. input voltage, reverse-current protection activation threshold, and SO-8 thermal derating capability.

Technical Context

The MAX603ESA+T employs a 1.20V internal bandgap reference and error amplifier driving a P-channel MOSFET pass transistor - eliminating base-drive current loss and enabling ultra-low IQ independent of load. Its Dual Mode™ architecture uses a comparator to select between internal fixed feedback (5V) and external resistor-adjustable output (1.25V–11V) based on SET pin voltage (<80mV for fixed mode).

Reverse-current protection activates when VIN falls 6–20mV below VOUT, switching substrate bias to the more positive rail and limiting reverse leakage to ≤10μA. Foldback current limiting engages at 350mA during short-circuit (VOUT < 0.8V) and up to 1.2A in normal operation, while thermal shutdown triggers at +160°C with 10°C hysteresis.

Key Specifications

Pinout & Package

MAX603ESA+T is housed in an 8-pin SOIC package (S8-7F outline, 1.8W power rating) with four dedicated GND pins (pins 2, 3, 6, 7) serving dual roles as electrical ground and thermal heatsinks - requiring soldering to large copper planes for rated power dissipation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout, low-IQ linear regulator applications.

Compared with LT1761ES5-5#TRMPBF and TLS850F0TESA1, the MAX603ESA+T uniquely balances 500mA capability, 15μA IQ, reverse-current protection, and Dual Mode™ flexibility in an industrial-temperature SO-8 package - making it optimal for portable, battery-backed, and thermally constrained applications where both efficiency and robustness are required.

Availability

MAX603ESA+T is available at Aetrix Electronics and suitable for portable instrumentation, solar-powered data loggers, and industrial handheld scanners requiring stable component supply, extended temperature operation (-40°C to +85°C), and long-term lifecycle support.

Supply support for MAX603ESA+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 company specializing in precision analog, mixed-signal, and power management ICs for industrial, medical, and communications systems.

The MAX603ESA+T belongs to Maxim's low-dropout linear regulator product line, engineered specifically for battery-powered and energy-constrained applications demanding ultra-low quiescent current, reverse-current isolation, and robust thermal protection.

FAQ

What is the maximum continuous output current for MAX603ESA+T at 5V output?

The MAX603ESA+T delivers up to 500mA continuously at 5V output when thermal limits are respected. At 500mA and 5V output, dropout is 320mV typ - requiring minimum input of 5.32V. Power dissipation must stay within the SO-8 package's 1.8W limit, which depends on PCB copper area and ambient temperature per Figure 4 in the datasheet.

Does MAX603ESA+T support adjustable output voltage, and how is it configured?

Yes, MAX603ESA+T supports adjustable output from 1.25V to 11V via external resistors on the SET pin. Connect R1 between OUT and SET, R2 between SET and GND. Output voltage follows VOUT = 1.20V × (1 + R1/R2). The internal 5V setting is disabled when SET voltage exceeds 150mV - confirmed by the dual-mode comparator in the functional diagram.

How does reverse-current protection work in MAX603ESA+T, and what is its activation threshold?

MAX603ESA+T monitors IN and OUT voltages and switches substrate bias to the more positive rail when VIN falls below VOUT. Reverse-current protection activates at ∆V = VOUT – VIN = 6mV (min) to 20mV (max), limiting reverse leakage to ≤10μA. This prevents backfeed from backup batteries or supercapacitors into a failing main supply rail.

What is the shutdown behavior of MAX603ESA+T, and what is the OFF pin threshold?

Driving the OFF pin low (≤0.4V) places MAX603ESA+T in 2μA shutdown mode, disabling all internal circuitry. The high-level threshold is VIN-dependent: ≥2.0V at VIN = 4V, ≥3.0V at VIN = 6V, and ≥4.0V at VIN = 11.5V. Fast edge rates (<1μs) are required - slow RC transitions may cause output glitches.

Can MAX603ESA+T operate with input voltage below 2.7V, and what happens near dropout?

No - absolute minimum input is 2.7V per Absolute Maximum Ratings. Below this, device behavior is undefined and may cause damage. Near dropout (e.g., VIN = 5.32V at 500mA), output remains regulated but quiescent current stays at 15μA typ due to P-channel MOSFET architecture; however, foldback current limiting deactivates, so short-circuit current is uncontrolled.