Analog Devices Inc./Maxim Integrated MAX6401BS22

Overview

MAX6401BS22 from Maxim Integrated is an ultra-low-power microprocessor supervisory circuit with active-high push-pull 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 portable battery-powered systems during power-up, brownout, or shutdown.

For engineers reviewing the MAX6401BS22 datasheet, MAX6401BS22 pinout, MAX6401BS22 application, or MAX6401BS22 equivalent, this device delivers guaranteed reset validity down to VCC = 1.0V, immunity to short VCC transients, manual reset input with internal 50kΩ pullup, and compatibility with µP bidirectional reset pins when paired with open-drain alternatives.

Technical Context

The MAX6401BS22 implements a precision bandgap reference comparator to detect VCC falling below 2.20V, triggering an active-high RESET signal that remains asserted for ≥100ms after VCC recovers. Its internal timer resets on every threshold breach, ensuring robust brownout recovery.

It features a dedicated MR input with 1µs minimum pulse width, 100ns glitch rejection, and 200ns MR-to-RESET delay; RESET output drives high with 500µA source capability (0.8×VCC min) and sinks up to 1.2mA while asserted, supporting direct interface with µP reset inputs requiring active-high assertion.

Key Specifications

Pinout & Package

MAX6401BS22 is housed in a 4-bump UCSP (2×2 mm) chip-scale package - footprint 70% smaller than SC70, optimized for space-constrained portable designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6400BS22 and MAX6402BS22, the MAX6401BS22 uniquely provides active-high push-pull reset without external components - simplifying design for modern µPs with active-high reset inputs while retaining identical threshold accuracy, ultra-low current, and UCSP footprint.

Availability

MAX6401BS22 is available at Aetrix Electronics and suitable for portable/battery-powered equipment, cell phones, and MP3 players requiring stable component supply with long-term lifecycle support.

Supply support for MAX6401BS22 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 voltage monitoring in space-constrained portable electronics - delivering precision reset supervision with minimal footprint and current draw.

FAQ

What is the exact reset threshold voltage of MAX6401BS22 and how stable is it across temperature?

The MAX6401BS22 has a factory-trimmed nominal reset threshold of 2.20V, with ±2.5% accuracy guaranteed over the full –40°C to +85°C operating range. At +25°C, the threshold is specified between 2.167V (min) and 2.233V (max). This stability eliminates need for external calibration and ensures consistent brownout detection across environmental conditions - critical for reliable operation in handheld devices where ambient temperature varies widely. The MAX6401BS22 achieves this using a precision bandgap reference comparator architecture.

Does MAX6401BS22 require external components to function as a complete reset supervisor?

No, the MAX6401BS22 requires no external components to operate as a fully functional reset supervisor. It integrates a precision voltage reference, comparator, reset timer, and push-pull driver - all within its UCSP-4 package. The MR input includes an internal 50kΩ pullup resistor, and the active-high RESET output drives directly into µP reset pins without needing a pullup. This integration reduces PCB area, BOM cost, and design validation effort - a key advantage confirmed in Maxim's application notes for portable equipment using MAX6401BS22.

How does the manual reset (MR) input behave on MAX6401BS22 during power-up and low-VCC conditions?

The MR input on MAX6401BS22 is active-low with an internal 50kΩ pullup to VCC, allowing it to remain functional even when VCC drops as low as 1.2V. A logic-low pulse ≥1µs on MR asserts RESET high immediately and holds it high for the full 100ms timeout period after MR returns high. This behavior is guaranteed down to VCC = 1.0V for RESET output validity, making MAX6401BS22 suitable for systems requiring manual intervention during brownout - such as field-service reset in PDAs or emergency recovery in pagers.

What is the supply current consumption of MAX6401BS22 and how does it scale with voltage and temperature?

The MAX6401BS22 draws only 500nA typical supply current at VCC = 3.0V and +25°C, rising to 1.0µA maximum at VCC = 5.5V and +85°C. Its ultra-low ICC enables multi-year battery life in always-on supervision roles - verified in Maxim's Typical Operating Characteristics plots showing <1µA across –40°C to +85°C at 3.3V. This performance makes MAX6401BS22 ideal for applications like MP3 players and pagers where standby current directly impacts usable runtime.

Can MAX6401BS22 be used in systems with bidirectional µP reset pins?

No - MAX6401BS22 features an active-high push-pull RESET output, which cannot be directly wired to bidirectional µP reset pins without risk of contention. For such interfaces, Maxim recommends the open-drain variants MAX6402BS22 or MAX6405BS22, which allow safe wired-OR connection with a single external pullup. The MAX6401BS22 is intended for µPs with dedicated active-high reset inputs; attempting to use it with bidirectional pins may cause excessive current flow or logic conflict during reset assertion.