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 transistor, 490mV dropout at 350mA, 30μA quiescent current, and -40°C to +85°C operating range - designed for battery-powered portable electronics requiring stable 5V rail generation from 6V–16.5V inputs.

For engineers reviewing the MAX1659ESA datasheet, MAX1659ESA pinout, MAX1659ESA application, or MAX1659ESA equivalent, this page delivers verified electrical parameters, thermal behavior under load, Dual Mode™ output configuration logic, shutdown timing (120μs exit), and SO-8 package thermal design guidance - all confirmed for the exact MAX1659ESA variant.

Technical Context

The MAX1659ESA implements a precision 1.21V internal reference with error amplifier feedback controlling a p-channel MOSFET pass element; its Dual Mode™ comparator selects between factory-trimmed 5V output (SET ≤ 65mV) or adjustable mode (SET > 65mV) via external resistor divider. Shutdown is active-low with 0.1μA bias current and sub-1μA supply draw.

Thermal protection activates at +165°C junction temperature with 10°C hysteresis; reverse-battery protection blocks conduction below -17V input; output short-circuit duration is infinite. The device maintains regulation down to 1.25V output in adjustable mode and supports up to 350mA continuous output with no base-drive current dependency.

Key Specifications

Pinout & Package

The MAX1659ESA is housed in an 8-pin SO (Small Outline) package with enhanced thermal performance (θ_JB = 69°C/W), rated for 1.2W continuous dissipation at +70°C ambient. IN pins (3, 6, 7) serve dual roles as power 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 TPS76350DBVR and MCP1703T-5002E/MB, the MAX1659ESA delivers higher output current (350mA), lower dropout (490mV), integrated reverse-battery protection (-17V), and thermal hysteresis - making it uniquely suited for ruggedized portable equipment demanding robustness and extended battery life.

Availability

MAX1659ESA is available at Aetrix Electronics and suitable for cellular phones, digital cordless phones, PCMCIA cards, and hand-held instruments requiring stable component supply across industrial temperature ranges and long production lifecycles.

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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.

The MAX1659ESA belongs to Maxim's micropower LDO family engineered for portable battery-operated systems - prioritizing ultra-low quiescent current, low dropout, and built-in protection features without external components.

FAQ

What is the guaranteed output voltage tolerance for MAX1659ESA over its full operating temperature range?

The MAX1659ESA guarantees a 5.00V output with ±1.5% tolerance (4.85V to 5.15V) across the full -40°C to +85°C temperature range, tested under conditions of 6V ≤ VIN ≤ 16.5V and 0mA < ILOAD < 350mA. This specification is production-tested and documented in the Electrical Characteristics table of the official MAX1659ESA datasheet.

Does MAX1659ESA support adjustable output voltage, and if so, what is the minimum achievable output?

Yes, the MAX1659ESA supports adjustable output voltage when the SET pin is left ungrounded and connected to an external resistive divider. In this mode, the output can be set as low as 1.25V - determined by the internal 1.21V reference and feedback equation VOUT = 1.21V × (1 + R1/R2). The minimum output occurs when R2 = 0 (SET tied directly to OUT), yielding VOUT = 1.21V, but datasheet specifies 1.25V as the practical minimum due to tolerance and layout considerations.

What thermal derating applies to MAX1659ESA above +70°C ambient temperature?

The MAX1659ESA SO-8 package has a continuous power dissipation rating of 1.2W at +70°C ambient, with linear derating of 14.5mW/°C above that temperature. For example, at +85°C ambient, maximum allowable power drops to 1.2W − (15°C × 14.5mW/°C) = 0.9825W. This derating assumes proper PCB thermal design - specifically, connecting IN pins (3, 6, 7) to a large copper plane per Maxim's land pattern guidelines.

Can MAX1659ESA be used with input voltages below 2.7V, and what happens if VIN falls below the specified minimum?

No, the MAX1659ESA is not characterized or guaranteed for operation below 2.7V input. If VIN drops below 2.7V, the device may lose regulation, exhibit increased dropout, fail to maintain 5V output, or enter undefined behavior - especially near the 1.25V minimum feedback threshold. Absolute maximum ratings specify IN-to-GND as -17V to +17V, but functional operation is strictly bounded by the 2.7V–16.5V input range stated in the Electrical Characteristics table.

How does the Dual Mode™ functionality of MAX1659ESA determine whether it operates in fixed or adjustable output mode?

The MAX1659ESA uses an internal 65mV comparator to monitor the voltage at the SET pin. When SET ≤ 65mV (typically achieved by grounding it), the internal feedback network engages, fixing the output at 5.00V. When SET > 65mV, the device switches to external feedback mode, allowing adjustment via resistors R1 and R2. This hardware-based decision requires no external configuration signals or firmware - it is fully autonomous and deterministic for each MAX1659ESA unit.