Analog Devices Inc./Maxim Integrated MAX6865UK19D1L+T

Overview

The MAX6865UK19D1L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring (1.9V reset threshold), manual reset input (MR), and watchdog timer (209s 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 MAX6865UK19D1L+T datasheet, MAX6865UK19D1L+T pinout, MAX6865UK19D1L+T application, or MAX6865UK19D1L+T equivalent, key selection criteria include its 1.9V factory-trimmed reset threshold, 10ms reset timeout, 209s watchdog period, guaranteed reset validity down to VCC = +1.1V, and immunity to short VCC transients - all critical for low-power embedded system reliability.

Technical Context

This device implements a dual-monitoring architecture: a precision bandgap-based voltage detector triggers reset when VCC falls below 1.9V ±2.5%, while a digital watchdog timer monitors WDI activity and expires if no edge occurs within 209s (typ). The internal 10kΩ MR pullup and glitch rejection (200ns) enable robust manual reset handling without external components.

The push-pull active-low RESET output drives directly to VCC or GND with VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.12V), and VOH ≥ 0.8×VCC at ISOURCE = 500µA - ensuring clean logic-level compatibility with µP reset inputs across 1.2V–5.5V supply range.

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 MAX6865UK19D1L+T, MAX6864UK19D1L+T offers identical core supervision but omits CT configurability, while TPS3836K33DBVR trades ultra-low power and watchdog capability for simpler 3.3V-only monitoring - making MAX6865UK19D1L+T uniquely suited for long-life, safety-critical, firmware-monitored battery systems.

Availability

MAX6865UK19D1L+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered wearables, and industrial sensor nodes requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.

Supply support for MAX6865UK19D1L+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 high-performance analog and mixed-signal ICs for power, sensing, and connectivity applications in demanding environments.

The MAX6854–MAX6869 family delivers nanopower supervisory functions specifically for battery-constrained systems where reliability, ultra-low ICC, and integrated watchdog supervision are mandatory - targeting medical, portable, and IoT edge devices.

FAQ

What is the exact reset threshold voltage of the MAX6865UK19D1L+T?

The MAX6865UK19D1L+T has a factory-trimmed reset threshold of 1.9V with ±2.5% tolerance over temperature (-40°C to +85°C). This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "19" corresponds to 1.900V nominal. The device guarantees valid reset assertion down to VCC = +1.1V, making it suitable for deep brownout detection in low-voltage battery systems.

Does the MAX6865UK19D1L+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK19D1L+T includes a watchdog timer with a typical timeout period of 209 seconds, designated by the "L" suffix in the part number. This long-duration watchdog is optimized for firmware that performs infrequent operations - such as periodic sensor reads or wireless transmissions - and clears on any rising or falling edge at the WDI pin. The timer remains disabled until VCC exceeds the 1.9V threshold and reset deasserts.

What type of reset output does the MAX6865UK19D1L+T provide, and how is it configured?

The MAX6865UK19D1L+T provides an active-low push-pull RESET output (Pin 1), as confirmed by its pin description and functional diagram. It drives low during VCC brownout, MR assertion, or watchdog timeout, and returns high after the 10ms reset timeout period. Unlike open-drain variants, it requires no external pullup resistor and sources/sinks sufficient current (VOH ≥ 0.8×VCC, VOL ≤ 0.3V) to directly drive standard µP reset inputs.

How is the reset timeout period set on the MAX6865UK19D1L+T?

The reset timeout period for the MAX6865UK19D1L+T is fixed at 10ms (minimum), indicated by the "D1" suffix in the part number. This value is factory-programmed and not user-configurable - unlike MAX6861–MAX6863 variants with CT pin selectability. The 10ms duration ensures sufficient hold time for most 8-/16-bit microcontrollers to complete internal initialization after power-up or reset recovery.

Is the MAX6865UK19D1L+T pin-compatible with other devices in the MAX68xx family?

The MAX6865UK19D1L+T uses the standard 5-pin SOT23-5 package and shares identical pinout with MAX6864/MAX6866/MAX6867/MAX6869 variants: Pin 1 = RESET, Pin 2 = GND, Pin 3 = MR, Pin 4 = WDI, Pin 5 = VCC. However, it is not pin-compatible with MAX6861–MAX6863 (which use CT instead of WDI) or MAX6854–MAX6856 (which lack WDI). Always verify function mapping before substitution.