Analog Devices Inc./Maxim Integrated MAX1658ESA+

Overview

MAX1658ESA+ from Maxim Integrated is a 350mA, fixed 3.3V low-dropout linear regulator with p-channel MOSFET pass transistor, 650mV dropout at 350mA, 30μA quiescent current, and -40°C to +85°C operating range in an 8-pin SO package. It delivers stable power to portable battery-powered systems requiring ultra-low supply current and reverse-battery protection.

For engineers reviewing the MAX1658ESA+ datasheet, MAX1658ESA+ pinout, MAX1658ESA+ application, or MAX1658ESA+ equivalent, key selection criteria include its Dual Mode™ operation (fixed 3.3V output), thermal shutdown at 165°C, 1μA shutdown current, and compatibility with 10μF low-ESR output capacitors for handheld instrumentation and PCMCIA cards.

Technical Context

The MAX1658ESA+ uses a p-channel MOSFET pass element to maintain low quiescent current across load range (0–350mA) and in dropout, eliminating base-drive losses inherent in bipolar designs. Its Dual Mode™ comparator monitors the SET pin voltage against a 65mV threshold to select between internal fixed-voltage feedback (3.3V) or external adjustable configuration.

Thermal protection activates at 165°C junction temperature with 10°C hysteresis, and reverse-battery protection disables substrate connection when VIN < GND down to -17V. The device supports input voltages from 2.7V to 16.5V and regulates with 0.003%/mA load regulation and 2.5mV_P-P output noise (10Hz–100kHz).

Key Specifications

Pinout & Package

MAX1658ESA+ is housed in an 8-pin SO (Small Outline) package with enhanced thermal performance (θ_JB = 69°C/W), rated for 1.2W continuous power dissipation at +70°C ambient (derated above). IN pins (3, 6, 7) serve dual roles as electrical inputs and thermal heatsinks - require direct connection to copper planes for optimal thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS76333DBVR and MCP1700T-3302E/MB, the MAX1658ESA+ provides higher output current (350mA), integrated reverse-battery protection, and hardware-configurable Dual Mode™ operation - making it uniquely suited for ruggedized portable electronics requiring both reliability and design flexibility in a thermally robust SO package.

Availability

MAX1658ESA+ is available at Aetrix Electronics and suitable for digital cordless phones, PCMCIA cards, and hand-held instruments requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX1658ESA+ 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, communications, and consumer applications.

The MAX1658ESA+ belongs to Maxim's micropower LDO family designed specifically for battery-powered portable equipment demanding ultra-low quiescent current, robust fault protection, and flexible output configuration in compact packages.

FAQ

What output voltage does the MAX1658ESA+ deliver, and how is it configured?

The MAX1658ESA+ delivers a factory-preset 3.3V output when the SET pin is grounded. This fixed output is guaranteed within ±3% over load (0–350mA), input (5V–16.5V), and temperature (-40°C to +85°C). If SET is left ungrounded and connected to an external resistor divider, the device operates in adjustable mode (1.25V–16V). The MAX1658ESA+ does not support 5V output - that function is exclusive to the MAX1659ESA+ variant.

What is the dropout voltage specification for the MAX1658ESA+, and under what conditions is it measured?

The MAX1658ESA+ has a typical dropout voltage of 650mV at 350mA output current, defined as (VIN – VOUT) when VOUT drops 100mV below its nominal value at VIN = VOUT + 2V. This specification applies with VIN ≥ 5V and TA = -40°C to +85°C. Dropout increases to 1500mV maximum at full load and elevated temperature, and remains as low as 2mV at 1mA load - confirming strong light-load efficiency.

Does the MAX1658ESA+ include reverse-battery protection, and what voltage level does it withstand?

Yes, the MAX1658ESA+ includes integrated reverse-battery protection that disables the internal p-channel MOSFET substrate connection when input voltage falls below ground. It withstands reverse input voltages down to -17V without damage. This feature eliminates the need for an external series diode in battery-replaceable systems, though a nonpolarized input capacitor is required to avoid damage during reverse polarity events.

How does the shutdown functionality work on the MAX1658ESA+, and what is its exit timing?

The MAX1658ESA+ enters shutdown when the SHDN pin is pulled to ≤0.4V (logic-low), reducing supply current to ≤1μA and placing the output in high-impedance state. The device exits shutdown in 120μs (typical) after SHDN rises above 2.0V (logic-high), delivering full 3.3V output. Shutdown bias current is ≤0.1μA, ensuring minimal loading on the control signal source.

What thermal performance characteristics define the MAX1658ESA+ package, and how should it be mounted for optimal cooling?

The MAX1658ESA+ uses a specialized 8-pin SO package with θ_JB = 69°C/W - significantly lower than standard SO-8 (170°C/W) - enabling 1.2W continuous power dissipation at +70°C ambient. For optimal thermal performance, all three IN pins (3, 6, 7) must be soldered directly to large copper planes acting as heatsinks; the datasheet provides pad-area vs. power-dissipation curves to guide layout design.