Analog Devices Inc./Maxim Integrated MAX6865UK22D5S+T

Overview

The MAX6865UK22D5S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, combining voltage monitoring (2.235V reset threshold), manual reset input (MR), and watchdog timer (209s typical timeout) with ultra-low 170nA supply current. It asserts an active-high push-pull RESET output during VCC brownout, MR assertion, or watchdog timeout, and holds reset for 450ms minimum after recovery - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK22D5S+T datasheet, MAX6865UK22D5S+T pinout, MAX6865UK22D5S+T application, or MAX6865UK22D5S+T equivalent, key selection criteria include its 2.235V factory-trimmed threshold, 450ms reset timeout, 209s watchdog period, active-high push-pull output, and guaranteed operation down to VCC = 1.1V - critical for low-voltage, long-life embedded systems.

Technical Context

This device implements a precision bandgap-based voltage monitor with ±2.5% threshold accuracy over -40°C to +85°C, coupled with a digital watchdog timer that clears on any WDI edge and expires if WDI remains static beyond 209s (typ). Its internal 10kΩ MR pullup and glitch rejection (200ns) enable robust manual reset without external components.

The reset logic combines asynchronous VCC-fall detection with a monotonic timeout counter; RESET deasserts only after both VCC exceeds VTH + hysteresis (0.5% of VTH) and the full tRP (450ms min) elapses. Immunity to sub-40µs VCC transients at 100mV overdrive ensures stability in noisy power environments.

Key Specifications

Pinout & Package

Package: 5-pin SOT23 (lead-free, +T suffix), footprint-compatible with industry-standard 5-lead SOT-23.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK22D5S+T, the MAX6865UK22D5S+T's active-high push-pull output simplifies interface and saves board space; versus TPS3837K22DBVR, it delivers 170nA operation and integrated watchdog - essential for long-life, safety-critical medical wearables.

Availability

MAX6865UK22D5S+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered diagnostics equipment, and low-power IoT endpoints requiring stable component supply across extended production lifecycles.

Supply support for MAX6865UK22D5S+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) designs precision analog and mixed-signal ICs for demanding industrial, medical, and communications applications.

The MAX68xx family delivers nanopower supervision with integrated watchdog and manual reset for battery-critical systems - engineered specifically for glucose monitors, patient wearables, and portable diagnostics where reliability and longevity are paramount.

FAQ

What is the exact reset threshold voltage of the MAX6865UK22D5S+T?

The MAX6865UK22D5S+T has a factory-trimmed reset threshold of 2.235V, with ±2.5% tolerance over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "22" corresponds to 2.235V nominal. The device guarantees valid reset assertion down to VCC = 1.1V, making it suitable for low-voltage brownout protection in medical sensors.

Does the MAX6865UK22D5S+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK22D5S+T includes a watchdog timer with a typical timeout period of 209 seconds, designated by the "L" suffix in its ordering code. The timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond this interval. This long timeout is optimized for infrequent firmware health checks in low-duty-cycle portable medical devices.

What type of reset output does the MAX6865UK22D5S+T provide, and how is it configured?

The MAX6865UK22D5S+T provides an active-high push-pull RESET output on Pin 1. Unlike open-drain variants, it does not require an external pullup resistor and can directly drive standard µP reset inputs. Its VOH is guaranteed ≥0.8 × VCC at 500µA source current, ensuring robust logic-level compatibility across its 1.2V–5.5V operating range.

How does the manual reset (MR) input function on the MAX6865UK22D5S+T?

The MR input on the MAX6865UK22D5S+T is an active-low signal with an internal 10kΩ pullup to VCC. Driving MR low initiates a reset that persists for the full 450ms timeout period after MR returns high. It accepts CMOS logic levels, rejects glitches <200ns, and requires no external debounce - enabling simple momentary switch implementation for field recalibration in medical devices.

Is the MAX6865UK22D5S+T compatible with lead-free PCB assembly processes?

Yes, the "+T" suffix in MAX6865UK22D5S+T explicitly denotes lead-free packaging compliant with RoHS and JEDEC J-STD-020 reflow profiles. The device uses matte tin plating and is qualified for standard Pb-free reflow cycles up to 260°C peak temperature, supporting modern high-reliability medical manufacturing requirements.