Analog Devices Inc./Maxim Integrated MAX6402BS22

Overview

MAX6402BS22 from Maxim Integrated is an ultra-low-power microprocessor supervisory circuit with open-drain active-low reset output, factory-trimmed 2.20V reset threshold (±2.5% over -40°C to +85°C), 100ms minimum reset timeout, and 500nA typical supply current at 3.0V - used to monitor VCC in battery-powered portable systems during power-up, brownout, or shutdown.

For engineers reviewing the MAX6402BS22 datasheet, MAX6402BS22 pinout, MAX6402BS22 application, or MAX6402BS22 equivalent, key selection criteria include its open-drain RESET output for bidirectional µP reset pin interfacing, guaranteed reset validity down to VCC = 1.0V, immunity to sub-200ns VCC transients, and UCSP-4 package compatibility with space-constrained handheld designs.

Technical Context

The MAX6402BS22 integrates a precision bandgap reference comparator and internal reset timer, asserting RESET low when VCC falls below 2.20V and holding it low for ≥100ms after VCC rises above threshold. Its open-drain output requires an external pullup resistor and supports wired-OR configurations with microcontrollers having bidirectional reset pins.

It features a manual reset input (MR) with internal 50kΩ pullup, 1µs minimum MR pulse width, and 100ns glitch rejection. Reset assertion remains valid down to VCC = 1.0V, and the device ignores fast negative-going VCC transients up to 200µs depending on overdrive magnitude.

Key Specifications

Pinout & Package

MAX6402BS22 is housed in a 4-bump (2×2 mm) UCSP™ chip-scale package (UCSP-4), offering 70% smaller footprint than SC70 and optimized for ultra-compact portable PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6402BS23-T, MAX6402BS22 offers lower threshold for earlier brownout intervention in 2.2V–2.4V systems; compared with TPS3808G12DBVR, it delivers 3.2× lower supply current and native open-drain support - critical for compact, long-life portable designs.

Availability

MAX6402BS22 is available at Aetrix Electronics and suitable for portable/battery-powered equipment, cell phones, and MP3 players requiring stable component supply with consistent UCSP-4 packaging and factory-trimmed 2.20V reset performance.

Supply support for MAX6402BS22 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 MAX6400–MAX6405 family was designed specifically for ultra-low-power microprocessor supervision in space-constrained portable electronics, emphasizing minimal quiescent current, precise factory-trimmed thresholds, and chip-scale packaging.

FAQ

What is the exact reset threshold voltage of MAX6402BS22 and how accurate is it over temperature?

The MAX6402BS22 has a nominal reset threshold of 2.20V, with ±2.5% accuracy guaranteed over the full operating temperature range of -40°C to +85°C. At +25°C, the threshold is specified between 2.167V (min) and 2.233V (max). This precision eliminates the need for external resistor dividers or calibration, making MAX6402BS22 ideal for battery voltage monitoring in portable devices where consistent brownout detection is critical.

Does MAX6402BS22 support bidirectional microprocessor reset pins, and how is this implemented?

Yes, MAX6402BS22 supports bidirectional µP reset pins via its open-drain active-low RESET output (B1 pin). This allows direct connection to microcontrollers like the Motorola 68HCxx series using a single external pullup resistor - enabling either the MAX6402BS22 or the µP itself to assert reset on the shared line. The design avoids level-shifting components and simplifies PCB routing in compact handheld layouts.

What is the minimum VCC voltage at which MAX6402BS22 guarantees correct reset output behavior?

MAX6402BS22 guarantees correct reset output logic state down to VCC = 1.0V, meaning RESET remains asserted (low) even as supply voltage collapses - ensuring safe shutdown and preventing erratic µP operation during deep brownout. This capability is confirmed across the full -40°C to +85°C temperature range and is essential for protecting nonvolatile memory writes in battery-powered systems.

How does the manual reset input (MR) function on MAX6402BS22, and what external components are needed?

The MR pin on MAX6402BS22 is an active-low input with an internal 50kΩ pullup resistor to VCC, so no external biasing is required. A momentary switch from MR to GND initiates a reset, and the device holds RESET low for the full 100ms timeout period after MR returns high. No debouncing circuitry is necessary due to built-in 100ns glitch rejection, though a 0.1µF capacitor to ground is recommended in noisy environments.

What package type does MAX6402BS22 use, and what are its key mechanical advantages?

MAX6402BS22 uses a 4-bump UCSP™ (Ultra Compact Silicon Package) measuring 2mm × 2mm, also designated UCSP-4. It is 70% smaller than the SC70 package, enabling placement in ultra-dense portable PCBs. The chip-scale construction minimizes parasitic inductance and thermal resistance, while the bump configuration supports fine-pitch reflow assembly - critical for modern handheld and wearable electronics designs.