Analog Devices Inc./Maxim Integrated MAX8633ELA+

Overview

MAX8633ELA+ from Maxim Integrated is a dual-output, pin-programmable LDO linear regulator in a 2mm × 2mm µDFN-8 package, delivering up to 300mA per output with 90mV dropout at 100mA and 54µA quiescent current (both LDOs active). It features an open-drain, active-low RESET output monitoring OUT2 with 120ms minimum timeout and 87% reset threshold, designed for battery-powered portable electronics requiring precise dual-rail regulation and power sequencing.

For engineers reviewing the MAX8633ELA+ datasheet, MAX8633ELA+ pinout, MAX8633ELA+ application, or MAX8633ELA+ equivalent, key selection criteria include dual 300mA output capability, programmable voltage combinations via P1/P2 logic states, integrated reset functionality tied to OUT2, low-noise operation (not applicable to MAX8633), and thermal shutdown protection at +165°C.

Technical Context

The MAX8633ELA+ integrates two independent p-channel MOSFET-based LDO regulators with internal 1.50V reference and error amplifiers, enabling stable regulation without external feedback resistors. Its power-on sequence enforces OUT2-first startup, with OUT1 enabled only after OUT2 reaches 87% of nominal voltage - ensuring controlled rail sequencing in multi-voltage systems.

RESET assertion is strictly conditioned on OUT2 voltage: driven low when VOUT2 falls below 82.5% of nominal, and released to high-impedance 120–180ms after VOUT2 rises above 87%. Output voltages are latched at power-on based solely on P1/P2 logic states (open/GND/IN), and remain fixed until full power cycle or simultaneous SHDN assertion.

Key Specifications

Pinout & Package

MAX8633ELA+ uses an 8-pin, 2mm × 2mm µDFN package with exposed paddle (EP) for thermal dissipation. The package is RoHS-compliant and lead-free, optimized for space-constrained portable designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX8635ELA+, MAX8633ELA+ simplifies control logic with a single SHDN but sacrifices independent rail disable capability; versus TPS70245PWP, it achieves superior size efficiency, lower dropout, and built-in reset - reducing total component count by at least three passive and active devices.

Availability

MAX8633ELA+ is available at Aetrix Electronics and suitable for cellular handsets, PDAs, notebook subsystems, and wireless LAN cards requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MAX8633ELA+ 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 MAX8633–MAX8636 family was designed specifically for space-constrained, battery-powered portable electronics needing dual, low-quiescent, pin-programmable LDO regulation with integrated power sequencing and supervision.

FAQ

What is the function of the RESET pin on the MAX8633ELA+?

The RESET pin on the MAX8633ELA+ is an open-drain, active-low output that monitors only the OUT2 rail. It asserts low when VOUT2 drops below 82.5% of its nominal voltage and releases to high-impedance 120–180ms after VOUT2 rises above 87%. This provides a reliable, resistor-free reset signal synchronized to the secondary output's stability, eliminating need for external supervisors in portable designs.

How are output voltages selected on the MAX8633ELA+?

Output voltages on the MAX8633ELA+ are selected using two tri-state logic inputs - P1 and P2 - each configurable as open, GND, or IN. At power-on, their combined state selects one of nine predefined OUT1/OUT2 voltage pairs (e.g., 2.80V/1.50V, 3.00V/2.80V). These settings are latched and cannot be changed dynamically; reconfiguration requires cycling power or asserting SHDN low simultaneously on both regulators.

Does the MAX8633ELA+ support independent shutdown of each output?

No, the MAX8633ELA+ does not support independent shutdown. It features a single SHDN input that disables both OUT1 and OUT2 simultaneously when driven low. For independent control, consider the MAX8635ELA+, which provides separate SHDN1 and SHDN2 inputs - a key functional distinction confirmed in the official selector guide and pin description table.

What is the maximum power dissipation of the MAX8633ELA+ in its µDFN package?

The MAX8633ELA+ in the 2mm × 2mm µDFN package has a maximum continuous power dissipation of 380mW at +70°C ambient, derating linearly by 4.8mW/°C above that temperature. This limit must be respected when calculating worst-case power: PD = (VIN(MAX) − VOUT1) × IOUT1 + (VIN(MAX) − VOUT2) × IOUT2. Exceeding this value risks thermal shutdown activation at +165°C junction temperature.

Is the MAX8633ELA+ compatible with low-ESR ceramic capacitors only?

Yes, the MAX8633ELA+ is optimized for ceramic output capacitors with low ESR (e.g., X7R or X5R dielectrics), requiring ≥2.2µF per output for full-spec stability across -40°C to +85°C. Tantalum capacitors are explicitly not recommended due to higher ESR, which degrades PSRR, noise performance, and transient response - as stated in the Capacitor Selection section of the datasheet.