Analog Devices Inc./Maxim Integrated MAX6865UK27D5L+T

Overview

The MAX6865UK27D5L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, combining voltage monitoring (2.700V factory-trimmed reset threshold), manual reset input (MR), and watchdog timer (209s typical timeout) with 170nA typical 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 MAX6865UK27D5L+T datasheet, MAX6865UK27D5L+T pinout, MAX6865UK27D5L+T application, or MAX6865UK27D5L+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to sub-40µs VCC transients, pin-selectable reset timeout compatibility, and lead-free SOT23-5 packaging for space-constrained portable designs.

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 (rising or falling) and triggers reset if WDI remains static beyond 209s (typ). The internal reset timeout generator uses RC-based timing with factory-trimmed D5 setting (450ms min).

The MAX6865UK27D5L+T features an internally pulled-up MR input (10kΩ to VCC), active-high push-pull RESET referenced to VCC, and operates across 1.2V–5.5V supply range. Its 170nA supply current at 2.5V enables multi-year operation on coin-cell batteries without compromising reset reliability.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, 2.9mm × 1.6mm footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK27D5S+T and TPS3836K33DBVR, the MAX6865UK27D5L+T uniquely delivers ultra-low 170nA ICC, long 209s watchdog coverage, and factory-trimmed 2.700V threshold in a single SOT23-5 package - enabling extended battery life and simplified layout in portable medical electronics.

Availability

MAX6865UK27D5L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign recorders, industrial handheld scanners, and smart wearable sensors requiring stable component supply across multi-year production cycles.

Supply support for MAX6865UK27D5L+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, mixed-signal, and power management ICs for demanding industrial, medical, and communications applications.

The MAX6854–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in battery-critical portable medical and consumer electronics, emphasizing nanoscale ICC, robust reset timing, and integrated watchdog safety.

FAQ

What is the exact reset threshold voltage of the MAX6865UK27D5L+T?

The MAX6865UK27D5L+T has a factory-trimmed reset threshold of 2.700V with ±2.5% tolerance over -40°C to +85°C, confirmed in Table 2 (Threshold Suffix Guide) where suffix '27' corresponds to 2.700V nominal. This value is laser-trimmed during production and does not require external calibration. The MAX6865UK27D5L+T maintains this accuracy across its full operating temperature range and supply voltage (1.2V–5.5V).

Does the MAX6865UK27D5L+T support active-high or active-low reset output?

The MAX6865UK27D5L+T provides an active-high push-pull RESET output, as specified in its pin description (Pin 1 function) and Selector Guide. This means RESET goes high during fault conditions (VCC < 2.700V, MR asserted, or WDI timeout) and returns low after the 450ms timeout expires. The MAX6865UK27D5L+T does not offer open-drain or active-low variants - those are assigned to other members of the MAX68xx family like MAX6856 or MAX6866.

What is the watchdog timeout period for the MAX6865UK27D5L+T?

The MAX6865UK27D5L+T features a watchdog timeout period of 209s (typical), indicated by the 'L' suffix in its part number. This value is confirmed in Table 3 (Watchdog Timeout) and applies across -40°C to +85°C. The watchdog timer resets on any rising or falling edge at WDI and triggers RESET if WDI remains static longer than 209s. The MAX6865UK27D5L+T's watchdog is fully functional only when VCC ≥ 1.2V.

Can the MAX6865UK27D5L+T operate with supply voltages below 1.8V?

Yes, the MAX6865UK27D5L+T operates from 1.2V to 5.5V and guarantees valid RESET assertion down to VCC = +1.1V, as stated in the Absolute Maximum Ratings and Electrical Characteristics tables. At 1.2V supply, its typical supply current is 190nA, and it maintains full reset monitoring functionality including MR input detection and watchdog timing. The MAX6865UK27D5L+T is therefore suitable for ultra-low-voltage systems such as energy-harvesting sensors or depleted battery scenarios.

Is the MR input of the MAX6865UK27D5L+T internally pulled up?

Yes, the MR input of the MAX6865UK27D5L+T includes an internal 10kΩ pullup resistor to VCC, as documented in the Pin Description section and Applications Information. This eliminates the need for an external pullup component. The MR pin is active-low with 0.3×VCC VIL and 0.7×VCC VIH thresholds, and features 250ns glitch rejection. When unused, MR may be left floating or tied to VCC - the MAX6865UK27D5L+T will not assert reset under either condition.