Analog Devices Inc./Maxim Integrated MAX603CSA+

Overview

The MAX603CSA+ 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 (2μA off mode), reverse-current protection, and thermal overload protection - ideal for battery-powered instrumentation and portable 5V systems.

For engineers reviewing the MAX603CSA+ datasheet, MAX603CSA+ pinout, MAX603CSA+ application, or MAX603CSA+ equivalent, key selection considerations include its fixed-5V output configuration, SO-8 package thermal performance (1.8W), Dual Mode™ adjustability via SET pin, dropout behavior under load, and compatibility with low-noise analog subsystems requiring stable 5V rails.

Technical Context

The MAX603CSA+ employs an internal 1.20V bandgap reference and error amplifier to regulate output by controlling a 500mA P-channel MOSFET pass transistor - eliminating base-drive current losses inherent in bipolar regulators. Its Dual Mode™ comparator selects between internal feedback (5V fixed) and external resistor network (1.25V–11V adjustable) based on SET pin voltage (<80mV for fixed mode).

Reverse-current protection activates when VIN falls 6–20mV below VOUT, switching substrate bias to limit reverse leakage to ≤10μA. Foldback current limiting provides 350mA short-circuit protection below 0.8V output and 1.2A limiting above 0.8V with sufficient VIN–VOUT margin, while thermal shutdown triggers at +160°C with 10°C hysteresis.

Key Specifications

Pinout & Package

MAX603CSA+ is housed in an 8-pin SOIC (Small Outline Integrated Circuit) package rated for 1.8W power dissipation at +70°C ambient, with four dedicated GND pins (pins 2, 3, 6, 7) serving as thermal conduction paths to PCB copper planes.

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 TLS850F3TLE, the MAX603CSA+ delivers optimal trade-off between ultra-low IQ (15μA), adequate 500mA output, and SO-8 thermal capability - making it uniquely suited for cost-sensitive, battery-constrained portable electronics where every microamp counts.

Availability

MAX603CSA+ is available at Aetrix Electronics and suitable for portable instrumentation, battery-powered medical devices, and industrial data loggers requiring stable component supply with guaranteed long-term availability and consistent parametric performance.

Supply support for MAX603CSA+ 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) designs precision analog, mixed-signal, and power management ICs for demanding industrial, medical, and communications applications.

The MAX603CSA+ belongs to Maxim's low-dropout linear regulator product line, engineered specifically for battery-powered systems where minimal quiescent current, robust fault protection, and reliable fixed-voltage regulation are essential.

FAQ

What output voltage does the MAX603CSA+ deliver?

The MAX603CSA+ delivers a factory-trimmed fixed output voltage of 5.00V ±2.5% (4.75V to 5.25V) when the SET pin is connected to GND. This specification is guaranteed over temperature (0°C to +70°C) and load (20μA to 500mA), with line regulation of ≤40mV across its 2.7V–11.5V input range. The MAX603CSA+ achieves this using an internal 1.20V reference and precision feedback divider.

Can the MAX603CSA+ be configured for adjustable output?

Yes, the MAX603CSA+ supports adjustable output from 1.25V to 11V via external resistors connected to the SET pin. When SET is left open or biased above 80mV, the internal feedback divider is disabled and the output follows VOUT = 1.20V × (1 + R1/R2). The MAX603CSA+'s near-zero SET input bias current (±10nA) allows high-value resistors to minimize power loss while maintaining accuracy.

What is the dropout voltage specification for the MAX603CSA+?

The MAX603CSA+ has a typical dropout voltage of 320mV at 500mA output current and 5V output, defined as the VIN–VOUT differential when VOUT drops 100mV below nominal. At lighter loads (200mA), dropout falls to 220mV. This low dropout enables operation from partially discharged batteries - for example, sustaining 5V output until a single Li-ion cell drops to 5.32V.

How does the MAX603CSA+ handle reverse current flow?

The MAX603CSA+ incorporates integrated reverse-current protection that activates when VIN falls 6–20mV below VOUT. Upon detection, internal circuitry switches substrate bias to the more positive node (OUT), turning off the P-channel pass transistor and limiting reverse leakage to ≤10μA. This allows backup supplies or batteries to maintain VOUT during primary input failure without external diodes.

What thermal derating applies to the MAX603CSA+ in SO-8 package?

The MAX603CSA+ SO-8 package has a maximum continuous power dissipation of 1.8W at +70°C ambient, derating linearly at 23.6mW/°C above that temperature. To sustain full 500mA output, PCB layout must provide effective thermal conduction: all four GND pins must connect to ≥1.3cm² copper pad per Maxim's recommended footprint, otherwise junction temperature may exceed +150°C under worst-case VIN–VOUT differentials.