Analog Devices Inc./Maxim Integrated MAX6864UK22D3L+

Overview

MAX6864UK22D3L+ from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 2.235V reset threshold (suffix '22'), 300ms minimum reset timeout (suffix 'D3'), and 209s typical watchdog timeout (suffix 'L'). It monitors VCC, responds to manual reset (MR), and triggers reset on watchdog expiration - designed for battery-critical systems like glucose monitors and portable medical devices.

For engineers reviewing the MAX6864UK22D3L+ datasheet, MAX6864UK22D3L+ pinout, MAX6864UK22D3L+ application, or MAX6864UK22D3L+ equivalent, key selection considerations 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 logic with no external components required.

Technical Context

The MAX6864UK22D3L+ 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 if WDI remains static beyond 209s (typ). Its reset assertion is latched and held for the full 300ms timeout after VCC recovery, MR release, or watchdog expiry.

This device uses BiCMOS process technology (2848 transistors) and operates across -40°C to +85°C. The watchdog timeout exhibits ±25% variation over temperature (95s to 487s), while reset threshold drift is limited to ±0.5%VTH hysteresis and normalized VTH variation of ±0.01 over -40°C to +85°C.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, surface-mount, lead-free (RoHS-compliant), 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 TPS3836K33DBVR and STM6315SW33F6F, the MAX6864UK22D3L+ uniquely delivers 2.235V precision threshold, 209s watchdog, and 170nA ICC in the same SOT23-5 footprint - making it the only viable option for 2.2V battery-powered medical devices requiring autonomous fault recovery.

Availability

MAX6864UK22D3L+ is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign loggers, and smart hearing aids requiring stable component supply across extended production lifecycles and strict medical-grade traceability.

Supply support for MAX6864UK22D3L+ 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 interface applications in industrial, medical, and communications markets.

The MAX6864UK22D3L+ belongs to the nanopower µP supervisory family, engineered specifically for ultra-low-power portable medical and battery-operated equipment requiring guaranteed reset integrity and autonomous watchdog protection.

FAQ

What is the exact reset threshold voltage of MAX6864UK22D3L+?

The MAX6864UK22D3L+ has a factory-trimmed reset threshold of 2.235V, with ±2.5% tolerance over temperature (-40°C to +85°C). This value is confirmed by the '22' suffix in the part number per Maxim's Threshold Suffix Guide (Table 2), and is validated in the Electrical Characteristics table where VTH = 2.235V (TYP) under VCC falling conditions.

Does MAX6864UK22D3L+ require an external pullup resistor on the RESET pin?

No, MAX6864UK22D3L+ does not require an external pullup resistor on the RESET pin because it features a push-pull active-low output configuration. The internal driver actively pulls RESET low during assertion and drives it high (to VCC) when deasserted - eliminating dependency on external components for level translation or current sourcing.

How does the watchdog timer in MAX6864UK22D3L+ clear and expire?

The MAX6864UK22D3L+ watchdog timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static (high or low) for longer than 209s (typ). The timer is disabled while RESET is asserted and resumes counting immediately upon RESET deassertion, as documented in the Functional Diagram and Figure 3 timing relationship.

Can MAX6864UK22D3L+ operate reliably at VCC = 1.1V?

Yes, MAX6864UK22D3L+ guarantees valid RESET output down to VCC = +1.1V, as explicitly stated in the Features list and Electrical Characteristics table. Below this voltage, RESET may become indeterminate, but the device continues asserting reset until VCC falls below operational limits - critical for detecting deep brownout in Li-ion systems.

What is the function of Pin 4 (WDI) on MAX6864UK22D3L+?

Pin 4 (WDI) on MAX6864UK22D3L+ is the watchdog input terminal. It monitors µP activity: a rising or falling edge clears the internal watchdog timer, while absence of transitions for >209s (typ) causes reset assertion. WDI accepts standard CMOS logic levels and rejects pulses shorter than 150ns, per the Electrical Characteristics table.