Analog Devices Inc./Maxim Integrated MAX6402BS22+T

Overview

MAX6402BS22+T from Maxim Integrated is an ultra-low-power microprocessor supervisory circuit in a 4-bump UCSP package, designed to monitor VCC supply voltage and assert an active-low open-drain reset signal when voltage falls below 2.20V. It features ±2.5% threshold accuracy over –40°C to +85°C, 100ms minimum reset timeout, manual reset input with internal 50kΩ pullup, and guaranteed reset validity down to VCC = 1.0V. It is used in battery-powered portable electronics requiring reliable power-on reset and brownout protection.

For engineers reviewing the MAX6402BS22+T datasheet, MAX6402BS22+T pinout, MAX6402BS22+T application, or MAX6402BS22+T equivalent, key selection considerations include its 2.20V factory-trimmed threshold, open-drain output configuration, 500nA typical supply current, UCSP-4 package footprint, and compatibility with bidirectional µP reset pins via external pullup.

Technical Context

The MAX6402BS22+T implements a precision bandgap reference comparator with factory-trimmed 2.20V reset threshold and 6.3mV hysteresis. Its reset logic asserts low on VCC undervoltage and remains asserted for ≥100ms after VCC recovers, with immunity to transients ≤200ns (glitch rejection) and ≤100mV overdrive.

It integrates a manual reset input (MR) with TTL/CMOS-compatible thresholds, internal 50kΩ pullup, and 1µs minimum pulse width requirement. The open-drain RESET output requires an external pullup resistor and supports wired-OR interfacing with bidirectional microcontroller reset pins.

Key Specifications

Pinout & Package

MAX6402BS22+T is housed in a 4-bump, 2mm × 2mm UCSP (Ultra Compact Silicon Package) with bottom-solder bumps - no leads or wire bonds. This chip-scale package reduces board area by 70% versus SC70 and enables ultra-thin portable designs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisory applications.

Compared with MAX6400BS22+T and TPS3123E12DBVR, the MAX6402BS22+T uniquely combines ultra-low 500nA supply current, open-drain flexibility for shared reset buses, and integrated MR-making it optimal for compact, battery-critical designs requiring both automatic and manual reset control.

Availability

MAX6402BS22+T is available at Aetrix Electronics and suitable for portable medical devices, wearable fitness trackers, industrial handheld scanners, smart remote controls, and battery-backed IoT edge nodes requiring stable component supply and long-term lifecycle support.

Supply support for MAX6402BS22+T 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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.

The MAX6400–MAX6405 family was designed specifically for ultra-low-power microprocessor supervision in space- and energy-constrained portable electronics, emphasizing minimal footprint, nanoscale quiescent current, and factory-trimmed voltage accuracy.

FAQ

What is the exact reset threshold voltage of the MAX6402BS22+T?

The MAX6402BS22+T has a factory-trimmed nominal reset threshold of 2.20V, with tolerance of ±2.5% over the full –40°C to +85°C temperature range. At +25°C, the threshold is specified as 2.167V (min) to 2.233V (max), per Table 1 in the datasheet. This precise value enables reliable brownout detection in 2.2V–2.5V system rails without external calibration.

Does the MAX6402BS22+T require an external pullup resistor on the RESET pin?

Yes, the MAX6402BS22+T features an open-drain RESET output and requires an external pullup resistor (typically 10kΩ to 100kΩ) to VCC or another logic rail. Without this resistor, the RESET signal cannot achieve a valid high logic level. This design enables wired-OR connection with other open-drain reset sources and direct interfacing to bidirectional microcontroller reset pins.

Can the MAX6402BS22+T operate with supply voltages below 2.2V?

Yes - the MAX6402BS22+T is fully operational and guarantees correct reset output logic down to VCC = 1.0V. While its reset threshold is 2.20V, the internal circuitry remains functional at lower supplies, allowing it to assert and maintain RESET low during deep brownout conditions. This ensures deterministic behavior even as the battery depletes below nominal voltage.

What is the function of the MR pin on the MAX6402BS22+T?

The MR (Manual Reset) pin on the MAX6402BS22+T is an active-low input with an internal 50kΩ pullup resistor to VCC. Pulling MR low asserts RESET immediately, and RESET remains asserted for the full 100ms timeout period after MR returns high. This allows hardware-initiated resets via momentary switches or logic signals without external components - a key feature for field service and test modes.

Is the MAX6402BS22+T pin-compatible with other members of the MAX6400–MAX6405 family?

Yes, all MAX6400–MAX6405 variants, including the MAX6402BS22+T, share identical UCSP-4 pinout (GND, RESET, MR, VCC) and footprint. However, output type differs: MAX6402BS22+T uses open-drain, while MAX6400BS22+T uses push-pull. Swapping requires verifying external circuit compatibility - especially presence/absence of pullup resistor and load drive requirements.