Analog Devices Inc./Maxim Integrated MAX8635ETA+

Overview

MAX8635ETA+ from Maxim Integrated is a dual 300mA pin-programmable LDO linear regulator in an 8-pin 3mm × 3mm TDFN package, operating from 2.7V to 5.5V input with 90mV typical dropout at 100mA and 54µA typical quiescent current. It delivers independently programmable output voltages (e.g., 2.85V/2.85V, 3.00V/2.85V, or 2.60V/2.60V) via P1/P2 logic inputs and supports battery-powered portable electronics requiring stable dual-rail regulation.

For engineers reviewing the MAX8635ETA+ datasheet, MAX8635ETA+ pinout, MAX8635ETA+ application, or MAX8635ETA+ equivalent, key selection criteria include independent SHDN1/SHDN2 control, absence of RESET output, no noise-bypass (BP) pin, and compatibility with ceramic capacitors ≥2.2µF for stability across –40°C to +85°C.

Technical Context

The MAX8635ETA+ integrates two p-channel MOSFET pass transistors with internal 1.50V reference and error amplifiers, enabling low-dropout operation proportional to load current and R_DS(ON). Its dual independent shutdown inputs (SHDN1, SHDN2) allow selective enable/disable of OUT1 and OUT2 without affecting the other regulator.

Output voltages are latched at power-on based on the logic states of P1 and P2 (open/GND/IN), supporting nine preset combinations per Table 3; subsequent changes to P1/P2 have no effect unless both SHDN inputs are pulsed low or supply is cycled. Thermal shutdown activates at +165°C with 15°C hysteresis, and current limiting is set to 400–600mA per output.

Key Specifications

Pinout & Package

MAX8635ETA+ uses an 8-pin, 3mm × 3mm TDFN package with exposed paddle (EP) soldered to PCB ground for thermal dissipation. Pin count and footprint match industry-standard 8-TDFN layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX8635ELA+, the MAX8635ETA+ offers superior thermal handling for sustained 300mA loads; compared with TPS7A20285PDBVR, it provides integrated dual-rail control, programmability, and lower quiescent current-but at higher cost and design integration effort.

Availability

MAX8635ETA+ is available at Aetrix Electronics and suitable for cellular handsets, digital cameras, notebook subsystems, and wireless LAN cards requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for MAX8635ETA+ 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 applications in industrial, medical, communications, and consumer markets.

The MAX8633–MAX8636 family was engineered specifically for space- and power-constrained portable electronics needing dual, pin-configurable, low-I_Q LDOs with minimal external components.

FAQ

What output voltage combinations does the MAX8635ETA+ support?

The MAX8635ETA+ supports nine preset dual-output voltage combinations determined by the logic states of P1 and P2 at power-on, including 2.80V/1.50V, 2.90V/1.50V, 3.00V/1.50V, 2.60V/1.80V, 2.80V/1.80V, 3.00V/2.50V, 3.00V/2.80V, 2.85V/2.85V, and 3.00V/3.00V. These values are fixed per Table 3 in the datasheet and cannot be altered dynamically.

Does the MAX8635ETA+ include a RESET output or noise-bypass (BP) pin?

No, the MAX8635ETA+ does not include a RESET output or BP pin. Unlike MAX8633 (RESET) or MAX8634/MAX8636 (BP), the MAX8635ETA+ is configured for dual independent shutdown control only. Its pinout omits both RESET and BP terminals, confirmed by the Pin Configurations diagram and Selector Guide.

How does shutdown sequencing work on the MAX8635ETA+?

The MAX8635ETA+ features independent SHDN1 and SHDN2 inputs: driving SHDN1 low disables only OUT1, while SHDN2 low disables only OUT2. Both outputs remain active when both pins are high. To fully shut down the device and reduce supply current to ≤1µA, both SHDN1 and SHDN2 must be driven low simultaneously.

What capacitor values are required for stable operation of the MAX8635ETA+?

The MAX8635ETA+ requires a minimum 2.2µF ceramic input capacitor (X5R/X7R dielectric) between IN and GND, and ≥2.2µF ceramic output capacitors on both OUT1 and OUT2. For loads under 150mA, output capacitance may be reduced to 1µF. Tantalum capacitors are not recommended due to higher ESR.

Is the MAX8635ETA+ RoHS-compliant and lead-free?

Yes, the MAX8635ETA+ is RoHS-compliant and lead-free, as indicated by the "+" suffix in the part number per Maxim's ordering information. All packages-including the 8-pin TDFN used for MAX8635ETA+-are lead-free and meet JEDEC J-STD-020 moisture sensitivity level 1 requirements.