Analog Devices Inc./Maxim Integrated MAX77839BEFQ+

Overview

The MAX77839BEFQ+ from Analog Devices is a high-efficiency buck-boost DC-DC converter optimized for single-cell Li-ion and low-voltage battery chemistries (≥1.8V discharge), delivering 3A continuous output current with 6μA quiescent current, 2.2MHz switching frequency, and seamless buck/boost mode transition. It supports 1.8V–5.5V input and 2.3V–5.3V adjustable output voltage, and is used in smartphones for ToF/facial recognition power rails.

For engineers reviewing the MAX77839BEFQ+ datasheet, MAX77839BEFQ+ pinout, MAX77839BEFQ+ application, or MAX77839BEFQ+ equivalent, key selection criteria include its POK open-drain GPIO function, 3.6A switching current limit (Option B), FC2QFN-11 package, active output discharge, and thermal/overvoltage protections - all critical for compact, battery-sensitive designs.

Technical Context

The MAX77839BEFQ+ implements a four-switch H-bridge buck-boost topology with current-mode PWM control at 2.2MHz (typ), enabling fast transient response and small external components. Its proprietary algorithm dynamically sequences four phases (Φ1–Φ4) to maintain regulation across input voltages below or above the output setpoint.

It integrates cycle-by-cycle overcurrent protection with a fixed 3.6A (typ) high-side current limit (Option B), undervoltage lockout (1.75V rising threshold), overvoltage protection (0.5V OUT–OUTS differential), and thermal shutdown at +150°C. The GPIO pin functions as an open-drain POK output, asserting low when VOUT is within ±10% of target.

Key Specifications

Pinout & Package

MAX77839BEFQ+ uses the 2.5mm × 2.0mm, 0.5mm pitch, 11-lead FC2QFN package (Package Code F112A2F+1), optimized for high-density portable PCBs with exposed thermal pad.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar buck-boost regulator applications.

Compared with TPS63900DSKR and RTQ2132BGQW, the MAX77839BEFQ+ uniquely balances 3A capability, 6μA IQ, and hardware POK in a 2.5mm × 2.0mm FC2QFN - making it optimal for space-constrained, battery-life-sensitive consumer electronics where deterministic power sequencing matters.

Availability

MAX77839BEFQ+ is available at Aetrix Electronics and suitable for smartphone ToF modules, asset tracking devices, cellular modems, and RF amplifier bias supplies requiring stable component supply with guaranteed long-term availability.

Supply support for MAX77839BEFQ+ 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

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and consumer markets.

The MAX77839 series is part of Analog Devices' power management portfolio designed specifically for ultra-low-power, high-efficiency battery-powered portable electronics requiring seamless voltage regulation across wide input ranges.

FAQ

What is the GPIO function of the MAX77839BEFQ+?

The MAX77839BEFQ+ GPIO pin is configured as an open-drain POK (power-ok) output. It asserts low when the regulated output voltage is within ±10% of the target set by the SEL resistor. This signal is used for hardware-based power sequencing in host systems. Unlike FPWM-capable variants, the MAX77839BEFQ+ does not support forced-PWM mode via this pin.

What switching current limit applies to the MAX77839BEFQ+?

The MAX77839BEFQ+ implements the "B" option, specifying a typical high-side switching current limit of 3.6A. This value is fixed per device variant and determines the maximum inductor peak current during overload or transient events. It is validated in the Electrical Characteristics table (ILIM, C/D options) and impacts external inductor selection per the recommended list in the datasheet.

Which package does the MAX77839BEFQ+ use, and what are its thermal characteristics?

The MAX77839BEFQ+ uses the 11-lead FC2QFN package (2.5mm × 2.0mm, 0.5mm pitch). Its junction-to-ambient thermal resistance (θJA) is 52.3°C/W on a four-layer board, and junction-to-case (θJC) is 0.20°C/W. These values enable reliable 3A continuous operation up to +105°C junction temperature when properly mounted on a thermally enhanced PCB with adequate copper area.

How is the output voltage set on the MAX77839BEFQ+?

The output voltage of the MAX77839BEFQ+ is set using a single external resistor (RSEL) connected between the SEL pin and AGND. The IC reads this resistance during startup to determine the target regulation point. For example, a 0Ω (short) sets VOUT = 3.3V, while a 40.2kΩ resistor sets VOUT = 3.6V. Resistor tolerance must be ≤1% to ensure ±1% output accuracy.

Does the MAX77839BEFQ+ support active output discharge, and how does it work?

Yes, the MAX77839BEFQ+ includes integrated active output discharge. When the device is disabled via EN or latched off by protection (e.g., thermal shutdown), a 100Ω internal switch connects OUT to PGND, discharging the output capacitor rapidly. This ensures the output falls below 0.4V within milliseconds, preventing unintended device wake-up or latch-up in downstream circuitry.