Analog Devices Inc./Maxim Integrated MAX604CSA

Overview

The MAX604CSA from Maxim Integrated is a 3.3V fixed-output, low-dropout linear regulator with P-channel MOSFET pass transistor, delivering up to 500mA output current, 240mV typical dropout at 200mA, 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 space-constrained battery-powered instrumentation.

For engineers reviewing the MAX604CSA datasheet, MAX604CSA pinout, MAX604CSA application, or MAX604CSA equivalent, key selection criteria include dropout performance at 3.3V loads, shutdown leakage under varying VIN, reverse-current threshold accuracy, thermal derating in SO-8 packages, and compatibility with 10μF ceramic output capacitors for stable transient response.

Technical Context

The MAX604CSA implements Dual Mode™ operation: internal feedback fixes VOUT to 3.3V when SET is grounded, while external resistor networks enable adjustable outputs from 1.25V to 11V using a precise 1.20V reference. Its error amplifier compares SET voltage against this reference and drives a P-channel MOSFET pass element with no gate drive current, enabling ultra-low IQ across load and temperature.

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 conditions and scales to 1.2A above 0.8V output, while thermal shutdown triggers at +160°C with 10°C hysteresis.

Key Specifications

Pinout & Package

MAX604CSA uses an 8-pin SOIC (SO-8) package rated for 1.8W continuous power dissipation at +70°C ambient, with four dedicated GND pins 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 TPS76333DBVR and MCP1826-3302E/DB, the MAX604CSA uniquely combines 500mA capability, 240mV dropout at 200mA, 15μA IQ, and integrated reverse-current protection - making it the only option among the three qualified for battery-backup and solar-harvesting systems requiring bidirectional isolation.

Availability

MAX604CSA is available at Aetrix Electronics and suitable for portable instrumentation, solar-powered data loggers, and handheld test equipment requiring stable component supply with guaranteed long-term manufacturability and RoHS-compliant packaging.

Supply support for MAX604CSA 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 MAX603/MAX604 series was designed specifically for battery-powered systems demanding ultra-low quiescent current, low dropout, and robust fault protection - targeting portable instruments, pagers, and solar-harvesting devices where efficiency and reliability are non-negotiable.

FAQ

What is the maximum continuous output current for MAX604CSA at 3.3V output?

The MAX604CSA delivers up to 300mA continuously while maintaining specified output voltage accuracy and thermal limits in its SO-8 package. At higher currents (up to 500mA), operation is permitted only with reduced input-output differential voltage - for example, ≤0.5V at 500mA - to stay within the 1.8W power dissipation limit and avoid thermal shutdown. Derating is required above +70°C ambient.

Does MAX604CSA support adjustable output voltages, and how is it configured?

Yes, the MAX604CSA supports adjustable output from 1.25V to 11V using external resistors connected to the SET pin. When SET is left open or pulled above 150mV, the device enters adjustable mode and regulates VOUT = 1.20V × (1 + R1/R2). The internal 3.3V preset is only active when SET is solidly grounded (≤80mV). Impedance to ground must remain <10kΩ in fixed mode to prevent spurious mode switching.

What capacitor values are required for stable operation of MAX604CSA?

For stable operation across temperature and load, the MAX604CSA requires a minimum 10μF output capacitor (low-ESR ceramic or tantalum) and 0.1μF–10μF input capacitor. Using <3.3μF output capacitance risks oscillation. The 10μF output cap ensures adequate phase margin, dampens load transients (≤0.2V step from 5mA to 500mA), and maintains PSRR >60dB below 10kHz.

How does reverse-current protection work in MAX604CSA, and what is its threshold?

MAX604CSA monitors the differential between OUT and IN pins and activates reverse-current protection when VOUT exceeds VIN by 6mV (typical) to 20mV (max). At that point, internal circuitry switches substrate bias to the more positive rail and turns off the P-channel pass transistor, limiting reverse leakage to ≤10μA. This prevents battery or supercapacitor discharge through the regulator when input power fails.

What is the thermal performance of MAX604CSA in SO-8 package, and how should PCB layout support it?

The MAX604CSA SO-8 package has θJB = 42°C/W and supports 1.8W continuous dissipation at +70°C ambient. To achieve this, all four GND pins (pins 2, 3, 6, 7) must be soldered to a large copper pad or internal ground plane - ideally ≥1.3 cm² per side on FR-4 - acting as primary heat path. Without proper GND thermal coupling, junction temperature can exceed +150°C even at moderate loads, triggering thermal shutdown.