Analog Devices Inc./Maxim Integrated MAX6865UK20D6S+T

Overview

MAX6865UK20D6S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 2.0V reset threshold (±2.5%), 1200ms minimum reset timeout, manual reset input (MR), and watchdog timer with 209s typical timeout. It monitors VCC in battery-powered medical and portable systems to ensure reliable µP initialization during brownout or software hang.

For engineers reviewing the MAX6865UK20D6S+T datasheet, MAX6865UK20D6S+T pinout, MAX6865UK20D6S+T application, or MAX6865UK20D6S+T equivalent, this page delivers verified electrical parameters, functional pin mapping, real-world use cases for glucose monitors and patient monitors, and validated alternative parts with documented timing and output differences.

Technical Context

The MAX6865UK20D6S+T integrates voltage monitoring, a manual reset input (MR), and a watchdog timer (WDI) in a single BiCMOS IC. Its reset assertion is triggered by VCC falling below 2.0V, MR low pulse ≥1µs, or WDI inactivity exceeding 209s (typ). The internal reset timeout is fixed at 1200ms (D6 option), and reset remains asserted until both VCC exceeds 2.0V and MR deasserts.

It supports push-pull active-high RESET output referenced to VCC, guarantees valid reset down to VCC = 1.1V, and features 10kΩ internal MR pullup. Watchdog clearing occurs on any WDI edge (rising/falling), MR assertion, or RESET assertion - enabling robust firmware supervision without external components.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, -40°C to +85°C operating range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK20D6S+T, MAX6864UK20D6S+T lacks active-high RESET compatibility, while TPS3837K20DBVR omits watchdog capability entirely - making MAX6865UK20D6S+T the sole choice for compact, low-power, watchdog-enabled 2.0V supervision in medical wearables.

Availability

MAX6865UK20D6S+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, and portable ECG recorders requiring stable component supply with full lifecycle support and traceable sourcing.

Supply support for MAX6865UK20D6S+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 industrial, medical, and communications applications, with expertise in low-power supervision and power management.

The MAX6854–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in battery-critical medical and portable electronics, integrating voltage monitoring, manual reset, and watchdog functions in minimal footprint.

FAQ

What is the exact reset threshold voltage of MAX6865UK20D6S+T?

The MAX6865UK20D6S+T has a factory-trimmed reset threshold of 2.0V with ±2.5% tolerance over temperature (-40°C to +85°C). This value is confirmed in Table 2 (Threshold Suffix Guide) where suffix "20" corresponds to 1.950V (min), 2.000V (typ), and 2.050V (max). The threshold remains stable across temperature, with normalized variation ≤±0.5% from -40°C to +85°C per typical characteristics graph.

Does MAX6865UK20D6S+T support active-high RESET output?

Yes, MAX6865UK20D6S+T provides a push-pull active-high RESET output, as confirmed in the Selector Guide (row MAX6865) and Pin Description section. When VCC drops below 2.0V, MR is pulled low, or WDI inactivity exceeds 209s, RESET transitions from low to high and remains high for the full 1200ms timeout period. This eliminates need for external level-shifting in µPs with active-high reset inputs.

What is the watchdog timeout behavior of MAX6865UK20D6S+T?

MAX6865UK20D6S+T uses the "L" watchdog suffix, delivering a typical timeout of 209s (min 95s, max 487s). The watchdog timer clears on any WDI edge (rising or falling), MR assertion, or RESET assertion. It does not require toggling - a single edge suffices. While RESET is asserted, the watchdog timer is disabled; it resumes counting only after RESET deasserts.

Can MAX6865UK20D6S+T operate down to 1.2V supply?

Yes, MAX6865UK20D6S+T operates across VCC = 1.2V to 5.5V per Absolute Maximum Ratings and Electrical Characteristics tables. Crucially, its RESET output remains valid down to VCC = 1.1V, ensuring reliable assertion even during severe brownout. At VCC = 1.2V, supply current is 190nA (typ), and reset threshold maintains ±2.5% accuracy.

Is an external pullup resistor required for MR on MAX6865UK20D6S+T?

No, MAX6865UK20D6S+T includes an internal 10kΩ pullup resistor from MR to VCC, as explicitly stated in the Pin Description and Detailed Description sections. MR may be left unconnected or tied to VCC when unused. External debounce is unnecessary; a momentary switch from MR to GND implements manual reset without additional components.