Analog Devices Inc./Maxim Integrated MAX1659ESA+

Overview

MAX1659ESA+ from Maxim Integrated is a 5V fixed-output, low-dropout linear regulator with p-channel MOSFET pass element, delivering up to 350mA output current, 490mV dropout at full load, 30μA quiescent current, and 1μA shutdown current. It operates across 2.7V–16.5V input range and targets battery-powered portable electronics requiring stable, low-noise 5V supply.

For engineers reviewing the MAX1659ESA+ datasheet, MAX1659ESA+ pinout, MAX1659ESA+ application, or MAX1659ESA+ equivalent, key selection criteria include dropout voltage at 350mA, thermal performance in 8-pin SO package, Dual Mode™ configurability (fixed vs. adjustable), reverse-battery protection, and PSRR performance above 50dB at 50Hz/60Hz.

Technical Context

The MAX1659ESA+ employs a p-channel MOSFET pass transistor to maintain ultra-low quiescent current across 0–350mA load range, including dropout operation. Its Dual Mode™ architecture uses a 65mV threshold comparator on the SET pin to select between internal 5V feedback (SET ≤ 65mV) or external resistive divider for adjustable output (1.25V–16V).

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 features integrated current limiting (~900mA), 2.5mV_P-P output noise (10Hz–100kHz), and 55dB PSRR at 50Hz.

Key Specifications

Pinout & Package

The MAX1659ESA+ is housed in an 8-pin SOIC package (S8+10F outline) with enhanced thermal performance (θ_JB = 69°C/W), rated for 1.2W continuous power dissipation at +70°C ambient (derated above).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT1763CS8-5#PBF and TCP1265ESE-5.0VCT, the MAX1659ESA+ uniquely combines 350mA capability, ultra-low 30μA quiescent current, reverse-battery tolerance, and Dual Mode™ flexibility-all in a thermally robust 8-pin SO package-making it optimal for space-constrained, battery-reliant portable systems.

Availability

MAX1659ESA+ is available at Aetrix Electronics and suitable for digital cordless phones, cellular handsets, and handheld instrumentation requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX1659ESA+ 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, automotive, and portable applications.

The MAX1658/MAX1659 product line delivers micropower, low-dropout regulators optimized for battery longevity and reliability in compact, high-density portable electronics-emphasizing ultra-low IQ, reverse-battery resilience, and thermal robustness.

FAQ

What is the guaranteed output voltage accuracy of the MAX1659ESA+ over temperature and load?

The MAX1659ESA+ guarantees 5.00V ±1.5% output voltage over –40°C to +85°C ambient temperature and 0–350mA load range, with VIN between 6V and 16.5V. This specification is validated per the datasheet's Electrical Characteristics table and applies to the factory-preset 5V mode when the SET pin is grounded. The MAX1659ESA+ achieves this stability using a 1.21V internal reference and precision feedback comparator.

Does the MAX1659ESA+ require external capacitors, and what are the minimum values?

Yes, the MAX1659ESA+ requires a minimum 10μF low-ESR (<0.2Ω) output capacitor from OUT to GND for stability across its full 350mA load range. An input bypass capacitor of 0.1μF to 10μF is also recommended. Using smaller output capacitors reduces maximum supported load current-e.g., 4.7μF supports up to 250mA. The MAX1659ESA+ does not operate stably without these external components.

How does the Dual Mode™ operation work on the MAX1659ESA+, and can it be reconfigured in-circuit?

Dual Mode™ on the MAX1659ESA+ is controlled by the voltage on the SET pin: grounding SET (≤65mV) selects fixed 5V output; applying >65mV enables adjustable mode using an external resistor divider. This configuration is fully dynamic-switching between modes occurs in real time without power cycling. The MAX1659ESA+ continuously monitors SET, allowing seamless in-system reconfiguration of output voltage.

What thermal derating applies to the MAX1659ESA+ in its 8-pin SO package?

The MAX1659ESA+ 8-pin SO package has a 1.2W continuous power dissipation rating at +70°C ambient, derating linearly by 14.5mW/°C above that temperature. Its specialized lead frame yields θ_JB = 69°C/W-significantly better than standard SOIC. To achieve rated thermal performance, all three IN pins must connect to a large copper pour; the MAX1659ESA+ datasheet provides pad-area vs. power-dissipation curves for layout optimization.

Is the MAX1659ESA+ protected against reverse-battery conditions, and what is the limit?

Yes, the MAX1659ESA+ includes integrated reverse-battery protection and withstands input voltages down to –17V without damage. This is achieved by disconnecting the substrate from IN when VIN falls below GND. The SHDN pin also tolerates reverse bias, enabling direct connection to IN. However, the MAX1659ESA+ does not block reverse current flow from VOUT to VIN-external Schottky diode is required if VOUT may exceed VIN by >300mV.