Analog Devices Inc./Maxim Integrated MAX6864UK29D1S+T

Overview

The MAX6864UK29D1S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, combining voltage monitoring (V_TH = 2.852 V), manual reset input (MR), and watchdog timer (t_WD = 3.3 s typ) with ultra-low 170 nA typical supply current. It asserts an active-low push-pull RESET output during V_CC brownout, MR assertion, or watchdog timeout - used in battery-powered glucose monitors and portable medical devices requiring guaranteed reset validity down to V_CC = 1.1 V.

For engineers reviewing the MAX6864UK29D1S+T datasheet, MAX6864UK29D1S+T pinout, MAX6864UK29D1S+T application, or MAX6864UK29D1S+T equivalent, key selection criteria include factory-trimmed 2.852 V reset threshold, 10 ms minimum reset timeout, 3.3 s watchdog period, push-pull active-low RESET output, and immunity to sub-40 µs V_CC transients.

Technical Context

This device implements a dual-trigger reset architecture: one path responds to V_CC falling below 2.852 V (±2.5%), the second to MR low assertion, and the third to WDI inactivity exceeding 3.3 s. All three conditions force RESET low for ≥10 ms after recovery.

The internal watchdog uses edge-triggered clearing (on rising/falling WDI transitions) and remains disabled during asserted RESET. The MR input features 10 kΩ internal pullup and 200 ns glitch rejection, while RESET output guarantees VOL ≤ 0.3 V at ISINK = 1.2 mA (V_CC ≥ 2.38 V).

Key Specifications

Pinout & Package

Package: 5-pin SOT23 (lead-free, +T suffix), footprint-compatible with industry-standard 5-lead SOT-23 packages.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK29D1S+T, the L-suffix variant trades faster fault detection (3.3 s vs. 209 s) for longer software margin, while TPS3836K33DBVR omits watchdog entirely and consumes ~9× more current - making MAX6864UK29D1S+T optimal for battery-critical, watchdog-requiring applications.

Availability

MAX6864UK29D1S+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign recorders, industrial handheld scanners, and wearable health trackers requiring stable component supply across multi-year production cycles.

Supply support for MAX6864UK29D1S+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 in industrial, medical, and communications markets.

The MAX6864UK29D1S+T belongs to the nanopower µP supervisory family engineered specifically for battery-operated medical and portable electronics where ultra-low ICC, guaranteed reset validity to 1.1 V, and integrated watchdog functionality are mandatory.

FAQ

What is the exact reset threshold voltage of the MAX6864UK29D1S+T?

The MAX6864UK29D1S+T has a factory-trimmed reset threshold voltage of 2.852 V, 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 "29" corresponds to 2.852 V nominal. The MAX6864UK29D1S+T maintains this accuracy without external calibration components.

Does the MAX6864UK29D1S+T require external components for basic operation?

No, the MAX6864UK29D1S+T operates autonomously with no external components required. Its internal 10 kΩ MR pullup, precision bandgap reference, and timing elements eliminate the need for external resistors or capacitors. Only a 0.1 µF V_CC-to-GND bypass capacitor is recommended for noise immunity - not mandatory but strongly advised per datasheet guidelines for the MAX6864UK29D1S+T.

What is the watchdog timeout behavior of the MAX6864UK29D1S+T?

The MAX6864UK29D1S+T features a watchdog timeout period of 3.3 s (typical), denoted by the "S" suffix. The internal timer clears on any rising or falling edge at WDI and expires only if WDI remains static (high or low) beyond this interval. Upon expiration, RESET asserts for the configured 10 ms minimum timeout - a behavior verified in Electrical Characteristics Table and Figure 3 of the MAX6864UK29D1S+T datasheet.

Can the MAX6864UK29D1S+T operate reliably below 1.8 V?

Yes, the MAX6864UK29D1S+T is fully specified from V_CC = 1.2 V to 5.5 V and guarantees valid RESET output down to V_CC = 1.1 V. At 1.2 V, supply current remains at 190 nA (typ), and RESET VOL stays ≤0.3 V with 50 µA sink current. This makes the MAX6864UK29D1S+T suitable for single-cell LiFePO₄ or deeply discharged alkaline systems.

Is the MAX6864UK29D1S+T pin-compatible with other supervisory ICs?

The MAX6864UK29D1S+T uses a standard 5-pin SOT23 package with pin 1 = RESET, pin 2 = GND, pin 3 = MR, pin 4 = WDI, pin 5 = V_CC. It is not pin-compatible with TPS3836/TPS3837/TPS3838 (which lack WDI and use different pinouts), nor with MAX6861–MAX6863 (CT pin instead of WDI). Direct replacement requires matching both function and pin mapping - confirmed by Pin Configurations section of MAX6864UK29D1S+T datasheet.