Analog Devices Inc./Maxim Integrated MAX6867UK17D3S+

Overview

The MAX6867UK17D3S+ from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, a factory-trimmed 1.665V reset threshold (suffix '17'), 150ms minimum reset timeout (D3), and a 3.3s typical watchdog timeout (S). It monitors VCC, responds to manual reset (MR) assertion, and triggers reset upon watchdog timer expiration - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6867UK17D3S+ datasheet, MAX6867UK17D3S+ pinout, MAX6867UK17D3S+ application, or MAX6867UK17D3S+ equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), push-pull active-low RESET output, and integrated MR/WDI interface with no external components required.

Technical Context

The MAX6867UK17D3S+ integrates three core functions: precision voltage monitoring with ±2.5% threshold accuracy over temperature, a manual reset input with 250ns MR-to-reset delay and internal 10kΩ pullup, and a watchdog timer that clears on any WDI edge and expires after 3.3s (typ) if inactive - supporting fail-safe recovery in embedded firmware.

Its architecture uses a BiCMOS process with 2848 transistors, enabling operation from 1.2V to 5.5V while maintaining sub-µA quiescent current. The device asserts RESET low when VCC drops below 1.665V, MR is pulled low, or WDI remains static beyond tWD; RESET remains asserted for ≥150ms after recovery conditions are met.

Key Specifications

Pinout & Package

Package: 5-pin SOT23 (lead-free, RoHS-compliant).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK16D3S+, the MAX6867UK17D3S+ provides higher reset threshold margin for 1.8V systems; versus TPS3836K33DBVR, it delivers 7× lower supply current and integrated watchdog - essential for firmware safety in long-life medical and IoT endpoints.

Availability

MAX6867UK17D3S+ is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign recorders, industrial handheld scanners, and low-power IoT edge sensors requiring stable component supply across extended production lifecycles.

Supply support for MAX6867UK17D3S+ 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 MAX6854–MAX6869 family targets ultra-low-power microprocessor supervision in battery-critical systems, emphasizing nanopower operation, robust reset timing, and integrated watchdog functionality for firmware reliability.

FAQ

What is the exact reset threshold voltage of the MAX6867UK17D3S+?

The MAX6867UK17D3S+ has a factory-trimmed reset threshold voltage of 1.665V (minimum 1.623V, maximum 1.707V) with ±2.5% tolerance over temperature. This value is defined by the '17' suffix in the part number and is guaranteed across the -40°C to +85°C operating range. The MAX6867UK17D3S+ asserts RESET when VCC falls below this threshold and holds it for ≥150ms after VCC rises above it.

Does the MAX6867UK17D3S+ require external components for basic operation?

No, the MAX6867UK17D3S+ requires no external components for core functionality: it includes an internal 10kΩ pullup on MR, precise voltage reference, and watchdog timer. A 0.1µF ceramic capacitor from VCC to GND is recommended for noise suppression, but is not mandatory for specification compliance. The MAX6867UK17D3S+ operates fully functional in its 5-pin SOT23 package with only VCC, GND, MR, WDI, and RESET connections.

How does the watchdog timer in the MAX6867UK17D3S+ respond to firmware activity?

The MAX6867UK17D3S+ watchdog timer clears on every rising or falling edge at the WDI pin and expires only if WDI remains static (high or low) for longer than 3.3s (typical). It does not require toggling - a single edge suffices to reset the timer. During RESET assertion, the watchdog is paused; it resumes counting immediately upon RESET deassertion. This behavior makes the MAX6867UK17D3S+ suitable for monitoring loop-based or interrupt-driven firmware without adding timing overhead.

Can the MAX6867UK17D3S+ operate reliably at VCC = 1.2V?

Yes, the MAX6867UK17D3S+ is fully specified to operate from VCC = 1.2V to 5.5V. Its reset output remains valid down to VCC = +1.1V, and supply current is characterized at 1.2V (190nA typ). At 1.2V, the device maintains full functionality: VTH monitoring, MR response, WDI edge detection, and RESET assertion/deassertion timing all meet datasheet specifications. This makes the MAX6867UK17D3S+ appropriate for single-cell lithium primary or rechargeable systems nearing end-of-discharge.

What is the function of Pin 1 (WDI) on the MAX6867UK17D3S+?

Pin 1 of the MAX6867UK17D3S+ is the Watchdog Input (WDI), which monitors µP firmware health. A rising or falling edge on WDI clears the internal watchdog timer; if WDI remains static for >3.3s (typ), the timer expires and triggers RESET for 150ms. WDI accepts CMOS-level signals (VIH = 0.7×VCC, VIL = 0.3×VCC) and detects pulses as short as 150ns. Unlike MR, WDI has no internal pullup and must be actively driven by the host µP - a key distinction in the MAX6867UK17D3S+ functional architecture.