Analog Devices Inc./Maxim Integrated MAX8634ELA+

Overview

MAX8634ELA+ from Maxim Integrated is a dual 300mA low-dropout linear regulator with pin-programmable output voltages, 90mV dropout at 100mA, 45µVRMS output noise, and independent SHDN1/SHDN2 control. It operates from 2.7V to 5.5V input and is designed for space-constrained battery-powered systems requiring stable dual-rail power with ultra-low quiescent current (54µA typical).

For engineers reviewing the MAX8634ELA+ datasheet, MAX8634ELA+ pinout, MAX8634ELA+ application, or MAX8634ELA+ equivalent, this page delivers verified electrical parameters, exact µDFN-8 package mapping, confirmed three-output-voltage selection logic (P input), thermal shutdown behavior, and real-world design implications of its p-channel MOSFET pass transistors and BP noise-bypass architecture.

Technical Context

The MAX8634ELA+ integrates two independent LDO regulators sharing a common 2.7V–5.5V input, each delivering up to 300mA with internal p-channel MOSFET pass devices enabling 90mV dropout at 100mA and 54µA no-load quiescent current. Its single programming input (P) selects among three fixed OUT1/OUT2 voltage pairs: (2.85V/2.85V), (3.00V/2.85V), or (2.60V/2.60V).

It features dedicated SHDN1 and SHDN2 inputs for independent regulator control, a BP pin accepting a 0.01µF capacitor to reduce reference noise and achieve 45µVRMS output noise (10Hz–100kHz), and thermal shutdown activation at +165°C with 15°C hysteresis - all in an 8-pin 2mm × 2mm µDFN package with exposed paddle.

Key Specifications

Pinout & Package

Package: 8-pin, 2mm × 2mm µDFN with exposed paddle (EP), RoHS-compliant, -40°C to +85°C operating range.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-LDO applications.

Compared with MAX8636ELA+, the MAX8634ELA+ offers independent SHDN1/SHDN2 for granular power management but fewer voltage options; compared with TPL7407LADGQR, it provides true regulated dual-rail LDO functionality with noise filtering and thermal protection - making it the only valid alternative for precision dual-voltage regulation.

Availability

MAX8634ELA+ is available at Aetrix Electronics and suitable for cellular handsets, digital cameras, wireless LAN cards, and handheld test instruments requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX8634ELA+ 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, communications, and consumer applications.

The MAX8633–MAX8636 family was engineered specifically for ultra-low-power, space-constrained battery-powered devices requiring dual independent LDOs with programmable outputs and minimal external components.

FAQ

What output voltage options does the MAX8634ELA+ support?

The MAX8634ELA+ supports three preset output-voltage combinations selected by the logic state of its single programming input (P): (2.85V/2.85V) when P is open, (3.00V/2.85V) when P = GND, and (2.60V/2.60V) when P = IN. These values are factory-trimmed and guaranteed over temperature; the MAX8634ELA+ does not support dynamic reconfiguration - voltage selection is latched at power-on or full shutdown.

How does the BP pin on the MAX8634ELA+ reduce output noise?

The BP pin on the MAX8634ELA+ connects to the internal voltage reference; adding a 0.01µF ceramic capacitor from BP to GND forms a low-pass filter that suppresses reference noise, lowering total output noise to 45µVRMS (10Hz–100kHz). Omitting the BP capacitor increases noise to ~60µVRMS but reduces component count - the MAX8634ELA+'s BP architecture enables design trade-offs between noise performance and solution size.

What is the maximum allowable power dissipation for the MAX8634ELA+ in its µDFN package?

The MAX8634ELA+ in the 2mm × 2mm µDFN package has a maximum continuous power dissipation of 380mW at +70°C ambient, derating by 4.8mW/°C above that temperature. Exceeding this limit risks thermal shutdown activation at +165°C; designers must calculate worst-case power (PD = (VIN−VOUT1)×IOUT1 + (VIN−VOUT2)×IOUT2) and verify it remains below PDMAX for their specific VIN, VOUT, and load conditions.

Can the MAX8634ELA+ regulate both outputs simultaneously at full 300mA load?

Yes, the MAX8634ELA+ can deliver 300mA from both OUT1 and OUT2 simultaneously, provided total power dissipation stays within the µDFN package's 380mW limit at the operating ambient temperature. For example, with VIN = 3.7V, VOUT1 = VOUT2 = 2.85V, and IOUT1 = IOUT2 = 300mA, PD = (3.7−2.85)×0.3 + (3.7−2.85)×0.3 = 510mW - exceeding the rating. Thus, full 300mA dual-load operation requires lower VIN, higher VOUT, reduced ambient, or the larger TDFN package.

Does the MAX8634ELA+ include current limiting and thermal protection?

Yes, the MAX8634ELA+ includes per-regulator current limiting (400mA min, 500mA typ) and comprehensive thermal protection: it disables both outputs when junction temperature exceeds +165°C and re-enables them only after cooling by 15°C (to +150°C). These protections are fully integrated and require no external components - they operate continuously during normal MAX8634ELA+ operation to prevent damage from overload or inadequate heatsinking.