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 and features shutdown mode (2μA), 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 criteria include dropout voltage under load, quiescent current stability across temperature, shutdown threshold behavior vs. input voltage, and SO-8 package thermal performance with multi-GND heatsinking.

Technical Context

The MAX603ESA+ uses an internal 1.20V bandgap reference and error amplifier to regulate output via a P-channel MOSFET pass transistor - eliminating base-drive current losses inherent in bipolar PNP regulators. Its Dual Mode™ architecture selects between fixed 5V output (SET = GND) or adjustable 1.25V–11V output (external resistor divider on SET pin) based on a confirmed 80mV dual-mode threshold.

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 provides 350mA short-circuit protection below 0.8V output and 1.2A limit above 0.8V with VIN–VOUT > 0.7V.

Key Specifications

Pinout & Package

MAX603ESA+ is housed in an 8-pin SOIC (SO-8) package with exposed thermal pad-compatible lead frame (θ_JB = 42°C/W), rated for 1.8W continuous power dissipation at T_A = +70°C. Four GND pins (2, 3, 6, 7) serve dual roles: electrical ground and thermal conduction - all must be soldered to large copper planes for reliable thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS76350DBVR and MCP1703T-5002E/MB, the MAX603ESA+ uniquely combines 500mA capability, sub-350mV dropout, 15μA I_Q, active shutdown, and reverse-current protection in a thermally robust SO-8 package - making it the only option for high-reliability, battery-limited systems demanding full-feature integration.

Availability

MAX603ESA+ is available at Aetrix Electronics and suitable for battery-powered devices, portable instruments, and solar-powered instruments requiring stable component supply with guaranteed long-term availability and extended temperature support (–40°C to +85°C).

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 semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.

The MAX603ESA+ belongs to Maxim's low-dropout linear regulator product line, engineered specifically for energy-constrained portable and remote systems where battery life, thermal efficiency, and fault resilience are critical design priorities.

FAQ

What is the maximum continuous output current for MAX603ESA+ at 5V output and 7V input?

The MAX603ESA+ delivers up to 500mA continuously at 5V output when input is 7V, provided thermal limits are respected. With its SO-8 package and four GND pins acting as heatsinks, sustained 500mA operation requires proper PCB copper area per Figure 4 in the datasheet. At 7V input, power dissipation is (7V – 5V) × 500mA = 1W - within the 1.8W SO-8 rating at T_A ≤ +70°C with adequate layout.

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

Yes, MAX603ESA+ supports adjustable output from 1.25V to 11V using Dual Mode™ operation. To enable adjustable mode, disconnect the SET pin from GND and connect an external resistor divider (R1 from OUT to SET, R2 from SET to GND). The output voltage follows V_OUT = 1.20V × (1 + R1/R2), with V_SET = 1.20V ±40mV. Fixed 5V mode is selected by tying SET to GND.

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

MAX603ESA+ monitors the differential between OUT and IN voltages. When V_OUT exceeds V_IN by 6mV (min) to 20mV (max), internal circuitry switches substrate bias to the more positive rail and turns off the P-channel pass transistor, limiting reverse current to ≤10μA. This prevents backfeed from backup batteries or supercapacitors into a failing primary supply.

What capacitor values are required for stable operation of MAX603ESA+?

For stable operation across –40°C to +85°C and up to 500mA load, MAX603ESA+ requires a minimum 10μF output capacitor (low-ESR tantalum or ceramic) and 0.1μF to 10μF input capacitor. Using <3.3μF output capacitance risks oscillation. Larger output capacitors improve load-transient response and PSRR above 10kHz; input capacitance ≥1μF enhances line-transient rejection.

Is MAX603ESA+ pin-compatible with other regulators in the MAX603/MAX604 family?

Yes, MAX603ESA+ shares identical SO-8 pinout and footprint with MAX604ESA+, MAX603CSA, and MAX604CSA. All variants use the same IN, GND×4, OFF, SET, and OUT pin assignments. However, output voltage differs: MAX603 variants deliver 5V (fixed), while MAX604 variants deliver 3.3V (fixed); substituting them requires verifying downstream voltage tolerance.