Analog Devices Inc./Maxim Integrated MAX1658ESA+T

Overview

MAX1658ESA+T from Maxim Integrated is a 3.3V fixed-output, 350mA low-dropout linear regulator with p-channel MOSFET pass element, 650mV dropout at 350mA, 30μA quiescent current, and -40°C to +85°C operating range. It delivers stable power in space-constrained portable electronics where battery life and thermal efficiency are critical.

For engineers reviewing the MAX1658ESA+T datasheet, MAX1658ESA+T pinout, MAX1658ESA+T application, or MAX1658ESA+T equivalent, key selection factors include its Dual Mode™ output configuration (fixed 3.3V or adjustable), reverse-battery protection, 1μA shutdown current, and SO-8 package thermal performance (1.2W dissipation).

Technical Context

The MAX1658ESA+T uses a p-channel MOSFET pass transistor to maintain ultra-low quiescent current (30μA typ.) across 0–350mA load and into dropout-unlike bipolar-based regulators that increase bias current under load. Its Dual Mode™ comparator monitors the SET pin voltage against a 65mV threshold to select between internal fixed-voltage feedback (3.3V) or external resistive divider for adjustable outputs (1.25V–16V).

Thermal protection activates at +165°C junction temperature with 10°C hysteresis, and reverse-battery protection disables substrate conduction when VIN < GND (down to -17V). The three IN pins serve dual roles: input connection and primary thermal path to PCB copper planes, enabling 69°C/W θ_JB via optimized lead frame design.

Key Specifications

Pinout & Package

MAX1658ESA+T is housed in an 8-pin SO (Small Outline) package with exposed thermal pad-compatible footprint (S8+10F), rated for 1.2W continuous power dissipation at +70°C ambient (derated 14.5mW/°C above). The IN pins (3, 6, 7) double as thermal vias-must connect to large copper planes for reliable 350mA operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX1658ESA+T, TPS76333DBVR offers smaller footprint but sacrifices 50mA output capability, reverse-battery immunity, and thermal safety; MCP1700T-3302E/MB excels in standby IQ but cannot sustain 350mA loads or support adjustable outputs-making MAX1658ESA+T the only choice for robust, high-current portable power rails requiring full protection suite.

Availability

MAX1658ESA+T is available at Aetrix Electronics and suitable for cellular phones, digital cordless phones, PCMCIA cards, hand-held instruments, and palmtop computers requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for MAX1658ESA+T 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+T belongs to Maxim's micropower LDO family designed specifically for battery-powered portable equipment-emphasizing ultra-low IQ, dropout resilience, and integrated protection features in compact packages.

FAQ

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

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

Can the MAX1658ESA+T safely operate with input voltages below 2.7V?

No-the MAX1658ESA+T has a specified minimum input voltage of 2.7V per Absolute Maximum Ratings and Electrical Characteristics tables. Operation below this level may cause regulation loss, increased dropout, or undefined behavior. For sub-2.7V inputs, consider alternative regulators such as the MAX1726 or TPS7A05 series, as the MAX1658ESA+T is not characterized or guaranteed below 2.7V.

Does the MAX1658ESA+T require an external capacitor on the SET pin for stability?

No-capacitors are not required on the SET pin. The MAX1658ESA+T's SET input has leakage current <25nA and is designed for direct connection to GND (for fixed 3.3V) or to a high-impedance resistive divider (for adjustable mode). Adding capacitance risks destabilizing the feedback loop or delaying mode switching; stability relies solely on proper OUT-to-GND bypassing (≥10μF, ESR <0.2Ω).

How does reverse-battery protection work in the MAX1658ESA+T, and what is its limit?

The MAX1658ESA+T integrates reverse-battery protection by using the p-channel MOSFET's body diode orientation and substrate control. When VIN falls below GND, the internal switch disconnects the substrate from IN, preventing latch-up or damage. It is rated for -17V continuous reverse input-verified per Absolute Maximum Ratings. Note: this protects only the IC, not polarized input capacitors, which require nonpolar alternatives under reverse conditions.

What is the thermal resistance (θ_JB) of the MAX1658ESA+T package, and why does it matter?

The MAX1658ESA+T uses a specialized 8-pin SO package with θ_JB = 69°C/W-significantly lower than standard SO-8 (170°C/W). This value quantifies junction-to-board thermal resistance and directly determines safe power dissipation: at +70°C ambient, the 1.2W rating assumes optimal IN-pin copper connections. Poor PCB thermal design raises junction temperature, risking thermal shutdown; thus θ_JB guides heatsinking requirements for sustained 350mA operation.