Analog Devices Inc./Maxim Integrated MAX603ESA

Overview

The MAX603ESA 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, features shutdown (2μA off mode), reverse-current protection, and thermal overload protection - ideal for battery-powered portable instruments and solar-powered devices.

For engineers reviewing the MAX603ESA datasheet, MAX603ESA pinout, MAX603ESA application, or MAX603ESA equivalent, key selection considerations include its -40°C to +85°C industrial temperature range, SO-8 package thermal performance (1.8W dissipation), Dual Mode™ adjustable/fixed output capability, and reverse-current protection threshold of 6–20mV.

Technical Context

The MAX603ESA implements a 1.20V bandgap reference, error amplifier, and MOSFET driver controlling an internal 500mA P-channel pass transistor. Its Dual Mode™ comparator selects feedback path based on SET pin voltage (<80mV for fixed 5V output; >150mV for adjustable mode using external resistors).

Reverse-current protection actively switches substrate bias between IN and OUT pins when VIN falls below VOUT by ≥6mV, limiting reverse leakage to ≤10μA. Foldback current limiting activates at VOUT < 0.8V (350mA limit) or VIN − VOUT > 0.7V (1200mA limit), with thermal shutdown engaging at TJ = +160°C and 10°C hysteresis.

Key Specifications

Pinout & Package

MAX603ESA uses an 8-pin SOIC (Small Outline Integrated Circuit) package rated for 1.8W continuous power dissipation at TA = +70°C, with GND pins (2,3,6,7) serving dual roles as electrical ground and thermal heatsinks - requiring connection to large copper planes for reliable high-current operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT1763CS8-5#TRPBF and TSP50C50DGKR, the MAX603ESA uniquely balances 500mA delivery, 320mV dropout, 15μA IQ, and integrated reverse-current protection in a thermally robust SO-8 package - making it optimal for industrial portable designs requiring reliability across voltage transients and supply failures.

Availability

MAX603ESA is available at Aetrix Electronics and suitable for battery-powered devices, portable instruments, and solar-powered instruments requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for MAX603ESA 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 MAX603ESA belongs to Maxim's low-dropout linear regulator product line, engineered specifically for energy-constrained portable and remote systems where extended battery life, supply fault resilience, and thermal robustness are critical design requirements.

FAQ

What is the maximum continuous output current of the MAX603ESA?

The MAX603ESA delivers up to 500mA continuous output current under proper thermal conditions - specifically when mounted on a PCB with sufficient copper area to sustain its 1.8W SO-8 power dissipation rating at TA = +70°C. At higher ambient temperatures or reduced heatsinking, the actual current must be derated per the thermal resistance (θJB = 42°C/W) and maximum junction temperature of +150°C. The MAX603ESA datasheet specifies 600mA absolute maximum short-circuit duration (1 minute), but 500mA is the guaranteed continuous rating.

Does the MAX603ESA support adjustable output voltage?

Yes, the MAX603ESA supports adjustable output voltage from 1.25V to 11V using external resistors connected to the SET pin - enabled by its Dual Mode™ architecture. When SET is grounded, it defaults to fixed 5V output. For adjustable mode, the output voltage follows VOUT = 1.20V × (1 + R1/R2), where R2 connects SET to GND and R1 connects OUT to SET. The MAX603ESA's SET pin draws only ±10nA, allowing high-value resistors (up to 1.5MΩ for R2) to minimize power loss while maintaining accuracy.

How does reverse-current protection work in the MAX603ESA?

The MAX603ESA's reverse-current protection activates when the input voltage (VIN) falls 6–20mV below the output voltage (VOUT), causing internal circuitry to switch the substrate bias to the more positive of IN or OUT. This turns off the P-channel pass transistor and limits reverse leakage to ≤10μA - preventing battery self-discharge or backfeed from backup supplies. Unlike discrete diode solutions, this feature requires no external components and maintains regulation integrity during switchover, making the MAX603ESA suitable for dual-supply systems like main + backup battery configurations.

What capacitor values are recommended for stable operation of the MAX603ESA?

For stable operation across temperature and load, the MAX603ESA requires a minimum 10μF output capacitor (low-ESR tantalum or ceramic) and an input capacitor of 0.1μF to 10μF. The 10μF output capacitor ensures phase margin and suppresses load-transient spikes; using <3.3μF risks oscillation. Larger input capacitors improve line-transient response and supply-noise rejection, especially when sourced from noisy adapters. All capacitors must be placed close to the MAX603ESA pins, with GND connections routed directly to the four SO-8 ground pads to maintain low-impedance return paths.

Is the MAX603ESA pin-compatible with the MAX604ESA?

No, the MAX603ESA and MAX604ESA are not pin-compatible in fixed-output mode due to differing internal feedback networks - though they share identical pinout, package, and terminal functions. The MAX603ESA is factory-trimmed for 5V output, while the MAX604ESA is trimmed for 3.3V. Both support Dual Mode™ adjustable operation via the SET pin, but substituting one for the other without adjusting external circuitry will result in incorrect output voltage. For drop-in replacement, select the same part number variant; cross-grade substitution requires validation of load regulation, dropout, and thermal behavior at the target output voltage.