Analog Devices Inc./Maxim Integrated MAX6865UK45D6L+T

Overview

The MAX6865UK45D6L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring (4.500V 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 maintains reset for 1200ms minimum after recovery - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK45D6L+T datasheet, MAX6865UK45D6L+T pinout, MAX6865UK45D6L+T application, or MAX6865UK45D6L+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), fixed 1200ms reset timeout, and 209s watchdog period - all critical for low-power embedded systems requiring deterministic fault recovery.

Technical Context

The MAX6865UK45D6L+T implements a precision bandgap-based voltage monitor with ±2.5% threshold accuracy over -40°C to +85°C, coupled to a digital watchdog timer that clears on any WDI edge and expires if WDI remains static beyond 209s (typ). Its internal 10kΩ MR pullup enables direct switch interfacing without external components.

This device uses BiCMOS process technology (2848 transistors) to achieve 170nA typical ICC at 2.5V/25°C while maintaining push-pull RESET output drive capability: VOH ≥ 0.8×VCC at ISOURCE = 500µA and VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.38V), ensuring robust logic-level compatibility across supply voltages.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5 (lead-free, +T suffix), 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 MAX6865UK45D6L+T, MAX6864UK45D6S+T offers faster watchdog response (3.3s vs. 209s) at identical pinout and reset timing, while TPS3837K33DBVR provides basic 3.3V supervision without watchdog - making MAX6865UK45D6L+T uniquely suited for long-cycle, safety-critical medical devices requiring both extended watchdog coverage and precise 4.5V rail monitoring.

Availability

MAX6865UK45D6L+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitoring devices, and wearable health trackers requiring stable component supply, long-term lifecycle support, and lead-free compliance.

Supply support for MAX6865UK45D6L+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 power, sensing, and interface applications, with emphasis on low-power and high-reliability solutions.

The MAX6854–MAX6869 family delivers nanopower supervisory functions specifically for battery-operated medical, portable, and industrial equipment where ultra-low ICC and guaranteed reset integrity are mandatory.

FAQ

What is the exact reset threshold voltage of the MAX6865UK45D6L+T?

The MAX6865UK45D6L+T has a factory-trimmed reset threshold of +4.500V, with ±2.5% tolerance over the full -40°C to +85°C temperature range. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "45" corresponds to 4.500V nominal. The device guarantees valid reset assertion down to VCC = +1.1V, making it suitable for deep brownout detection in battery-powered systems.

Does the MAX6865UK45D6L+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK45D6L+T includes a watchdog timer with a typical timeout period of 209 seconds, as indicated by the "L" suffix in the part number. This is verified in Table 3 (Watchdog Timeout) of the datasheet, where "L" denotes 95s (min), 209s (typ), and 487s (max). The timer resets on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond this interval - critical for detecting firmware hangs in long-running medical algorithms.

What type of RESET output does the MAX6865UK45D6L+T provide, and how is it configured?

The MAX6865UK45D6L+T provides an active-high push-pull RESET output, confirmed by its position in the Selector Guide (row MAX6865, column "Push-Pull Active High") and Pin Description section. This means the output drives high during reset assertion and low during normal operation - eliminating the need for an external pullup resistor. The output meets VOH ≥ 0.8×VCC at 500µA source current and VOL ≤ 0.3V at 1.2mA sink current (VCC ≥ 2.38V), ensuring robust logic-level compatibility.

What is the reset timeout period for the MAX6865UK45D6L+T, and how is it set?

The MAX6865UK45D6L+T has a fixed reset timeout period of 1200ms (minimum), as specified by the "D6" suffix in the part number and confirmed in Table 4 (Reset Timeout Periods). This value is factory-programmed and cannot be adjusted externally. The timeout begins when VCC rises above the 4.500V threshold or MR is deasserted, and ensures the microprocessor and peripherals have sufficient time to stabilize before release - essential for reliable boot in medical-grade devices.

Is the MAX6865UK45D6L+T pin-compatible with other devices in the MAX68xx family?

Yes, the MAX6865UK45D6L+T uses the standard 5-pin SOT23-5 package and shares identical pinout with all MAX6864–MAX6869 variants: Pin 1 = RESET, Pin 2 = GND, Pin 3 = MR, Pin 4 = WDI, Pin 5 = VCC. This is explicitly shown in the "Pin Configurations" diagram (page 15) and "MAX6864/MAX6865/MAX6866 Pin Description" table (page 8). However, it is not pin-compatible with MAX6854–MAX6856 or MAX6861–MAX6863, which assign different functions to Pin 1 and Pin 4.