Analog Devices Inc./Maxim Integrated MAX6865UK46D1S+T

Overview

The MAX6865UK46D1S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring (4.625V factory-trimmed reset threshold), manual reset input (MR), and watchdog timer (3.3s typical timeout) with ultra-low 170nA typical supply current. It asserts an active-low push-pull RESET output during VCC brownout, MR assertion, or watchdog timeout, and holds reset for 10ms minimum after recovery - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK46D1S+T datasheet, MAX6865UK46D1S+T pinout, MAX6865UK46D1S+T application, or MAX6865UK46D1S+T equivalent, this page delivers verified functional identity, exact reset threshold and timeout values, confirmed watchdog behavior, validated pin configuration, and real-world design implications for low-power 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 3.3s (typ). The internal reset timeout generator guarantees ≥10ms assertion after VCC rises above 4.625V or MR deasserts.

It features a dedicated MR input with 10kΩ internal pullup, glitch rejection of 200ns, and MR-to-reset delay of 250ns. The push-pull RESET output drives low to ≤0.3V at 1.2mA sink (VCC ≥ 2.38V) and high to ≥0.8×VCC at 500µA source, remaining valid down to VCC = 1.1V.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free (RoHS-compliant), footprint compatible with industry-standard 5-pin SOT23 layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK46D1S+T, the MAX6865UK46D1S+T adds CT pin flexibility for future timeout upgrades, while versus TPS3836K33DBVR it delivers true nanopower operation, precise 4.625V threshold, and essential watchdog coverage for safety-critical firmware.

Availability

MAX6865UK46D1S+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign loggers, portable ultrasound probes, and handheld diagnostic scanners requiring stable component supply across extended production lifecycles.

Supply support for MAX6865UK46D1S+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 semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.

The MAX68xx family was designed specifically for ultra-low-power microprocessor supervision in battery-constrained medical and portable electronics, emphasizing nanopower consumption, guaranteed reset validity down to 1.1V, and integrated watchdog functionality.

FAQ

What is the exact reset threshold voltage of the MAX6865UK46D1S+T?

The MAX6865UK46D1S+T has a factory-trimmed reset threshold voltage of 4.625V, with ±2.5% tolerance over the full -40°C to +85°C operating range. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix '46' corresponds to VTH = 4.625V (typ). The MAX6865UK46D1S+T maintains this threshold stability across temperature, with normalized variation ≤±0.5% from -40°C to +85°C per the Typical Operating Characteristics graph.

Does the MAX6865UK46D1S+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK46D1S+T includes a watchdog timer with a typical timeout of 3.3s, indicated by the 'S' suffix in the part number. The watchdog clears on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond this period. The datasheet specifies min/typ/max values of 1.5s/3.3s/7.75s, and the MAX6865UK46D1S+T is characterized to meet the typical 3.3s value under standard conditions.

What is the reset timeout period for the MAX6865UK46D1S+T, and is it configurable?

The MAX6865UK46D1S+T has a fixed reset timeout period of 10ms minimum, denoted by the 'D1' suffix. Unlike MAX6861–MAX6863 variants, it does not feature a CT pin for timeout selection. The 'D1' option provides the shortest available timeout in the family, ensuring rapid system recovery after fault conditions while meeting µP initialization requirements. The MAX6865UK46D1S+T guarantees ≥10ms assertion regardless of VCC slew rate or temperature.

What output type does the MAX6865UK46D1S+T RESET pin provide?

The MAX6865UK46D1S+T provides an active-low push-pull RESET output, confirmed by its position in the Selector Guide (row MAX6865) and Pin Description section. This means the RESET pin actively drives low (≤0.3V at 1.2mA) and actively drives high (≥0.8×VCC at 500µA), eliminating the need for an external pullup resistor and ensuring robust interfacing with standard µP reset inputs. The MAX6865UK46D1S+T does not offer open-drain or active-high variants.

Is the MAX6865UK46D1S+T compatible with 1.8V or 2.5V supply rails?

Yes, the MAX6865UK46D1S+T operates across a VCC range of 1.2V to 5.5V and guarantees RESET validity down to VCC = 1.1V, making it fully compatible with 1.8V and 2.5V logic systems. Its 4.625V reset threshold is intended for monitoring higher rails (e.g., 5V LDO outputs), but the device itself can be powered from lower supplies while still supervising a separate higher-voltage domain - a common architecture in mixed-rail portable medical devices. The MAX6865UK46D1S+T's supply current remains at 170nA typical even at 1.8V.