Analog Devices Inc./Maxim Integrated MAX1642EUA+

Overview

The MAX1642EUA+ from Maxim Integrated is a high-efficiency, low-voltage step-up DC-DC converter optimized for single-alkaline-cell operation. It features a guaranteed 0.88V start-up voltage, 83% peak efficiency at 20mA output, 4µA quiescent supply current into the BATT pin, and an integrated synchronous rectifier. It delivers a fixed 3.3V ±4% output or adjustable 2V–5.2V output in ultra-small µMAX-8 package for space-constrained portable medical monitors.

For engineers reviewing the MAX1642EUA+ datasheet, MAX1642EUA+ pinout, MAX1642EUA+ application, or MAX1642EUA+ equivalent, key selection criteria include minimum input voltage (0.88V), shutdown current (2µA), FB set voltage (1.23V), reverse battery protection capability, and compatibility with 100µH inductors in low-profile µMAX packaging.

Technical Context

The MAX1642EUA+ employs pulse-frequency-modulation (PFM) control with variable on-time (K = 25V·µs typical) and minimum off-time tracking to maintain high efficiency across wide load and input voltage ranges (0.88V–1.65V). Its internal 1Ω N-channel MOSFET switch and built-in synchronous rectifier eliminate external catch diode requirements.

It integrates a logic-controlled shutdown input (SHDN), power-fail detection via PFI/PFO comparator (614mV trip, 1% hysteresis), and reverse-battery protection limiting reverse current to 220mA. The device draws power from the OUT pin and regulates using feedback at the FB pin referenced to 1.23V.

Key Specifications

Pinout & Package

Package: 8-pin µMAX (3.0mm × 3.0mm × 1.1mm height), exposed pad not electrically connected, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-up converter applications.

Compared with MAX1643EUA+, the MAX1642EUA+ provides host-controllable shutdown instead of autonomous battery-low signaling-critical for systems needing precise power sequencing. Versus TPS61200DRCR, MAX1642EUA+ uniquely supports sub-1V start-up essential for maximizing single-alkaline cell utilization.

Availability

MAX1642EUA+ is available at Aetrix Electronics and suitable for personal medical monitors, remote controls, pagers, pointing devices, and single-cell battery-powered instrumentation requiring stable component supply and long-term lifecycle support.

Supply support for MAX1642EUA+ 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, medical, and portable applications.

The MAX1642/MAX1643 product line was engineered specifically for ultra-low-voltage, high-efficiency boost conversion in single-primary-cell systems-prioritizing start-up reliability, quiescent current, and small-footprint integration.

FAQ

What is the guaranteed minimum input voltage for MAX1642EUA+ start-up?

The MAX1642EUA+ guarantees start-up at 0.88V under all conditions, verified per datasheet Figure TOC07a/TOC07b. This enables operation from deeply discharged alkaline cells where other boost converters fail. The 0.88V specification applies across -40°C to +85°C and is independent of output load or capacitor selection. MAX1642EUA+ achieves this via a dedicated low-voltage bootstrap oscillator that pumps the output to ~1.7V before main regulation begins.

How does the MAX1642EUA+ implement reverse battery protection?

The MAX1642EUA+ incorporates an internal 5Ω resistor in series with a protection diode on the BATT pin, limiting reverse current to ≤220mA during accidental battery reversal. This prevents thermal damage while allowing safe handling during assembly or field replacement. The 220mA limit is validated per Absolute Maximum Ratings and Typical Operating Characteristics. MAX1642EUA+ continues normal operation after polarity correction without latch-up or parameter shift.

Can MAX1642EUA+ be configured for adjustable output voltage?

Yes, MAX1642EUA+ supports adjustable output from 2V to 5.2V using two external resistors connected between OUT, FB, and GND. The FB pin regulates to 1.23V, so R1 = R2 × (VOUT/1.23 − 1). For example, 5.0V output requires R1 = 3.07 × R2. R2 should be 100kΩ–1MΩ to minimize leakage error. Fixed 3.3V operation is achieved by connecting FB directly to GND-no resistors needed. MAX1642EUA+ maintains regulation accuracy and efficiency across the full range.

What is the shutdown current specification for MAX1642EUA+?

MAX1642EUA+ draws 2µA typical current into the BATT pin when SHDN is pulled low, as specified in Electrical Characteristics Table (TA = -40°C to +85°C). This ultra-low shutdown current preserves battery capacity during extended idle periods. The device disables its internal MOSFET, places PFO in high-impedance state, and turns off the synchronous rectifier-though forward conduction through the body diode remains. MAX1642EUA+ resumes regulation within microseconds of SHDN returning high.

Which inductor value is recommended for MAX1642EUA+ in standard applications?

A 100µH inductor is recommended for most MAX1642EUA+ applications, as validated in Figures 2 and 4 of the datasheet and Table 2. Sumida CD54-101 and TDK NLC565050T-101K are qualified parts with 350mA saturation current and ≤1Ω DCR. Lower values (e.g., 68µH) increase max output current but raise ripple; higher values (e.g., 220µH) reduce peak current and noise. Inductor selection directly impacts MAX1642EUA+ efficiency, start-up behavior, and thermal performance.