Analog Devices Inc./Maxim Integrated MAX6864UK31D3L+T

Overview

MAX6864UK31D3L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 3.075V reset threshold (suffix "31"), 150ms 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 timeout - designed for battery-critical portable medical and handheld devices.

For engineers reviewing the MAX6864UK31D3L+T datasheet, MAX6864UK31D3L+T pinout, MAX6864UK31D3L+T application, or MAX6864UK31D3L+T equivalent, key selection criteria include 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 MAX6864UK31D3L+T integrates three core functions: precision voltage monitoring with ±2.5% threshold accuracy, 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 BiCMOS process enables stable operation across -40°C to +85°C with <0.5%VTH hysteresis.

Reset assertion occurs when VCC falls below 3.075V, MR is pulled low, or WDI fails to toggle within the watchdog period; reset remains asserted for ≥150ms after VCC rises above threshold and MR deasserts. The push-pull RESET output sinks ≤0.3V at 1.2mA (VCC ≥ 2.38V) and sources ≥0.8×VCC at 500µA, ensuring robust interface with µP reset inputs.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free (RoHS-compliant), 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 TPS3836K33DBVR and MAX6361KA29D3+T, the MAX6864UK31D3L+T uniquely combines factory-trimmed 3.075V threshold, 150ms reset timeout, integrated watchdog with 209s period, and MR input in a single 5-pin SOT23 - enabling full supervisory functionality without external components or design compromises.

Availability

MAX6864UK31D3L+T is available at Aetrix Electronics and suitable for portable medical monitoring, battery-powered handhelds, low-power wearables, and remote patient monitoring requiring stable component supply and long-term lifecycle support.

Supply support for MAX6864UK31D3L+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.

The MAX6864UK31D3L+T belongs to Maxim's nanopower µP supervisory family, engineered specifically for ultra-low-power, space-constrained portable electronics where battery longevity and fail-safe reset integrity are critical.

FAQ

What is the exact reset threshold voltage of the MAX6864UK31D3L+T?

The MAX6864UK31D3L+T has a factory-trimmed reset threshold voltage of 3.075V, with ±2.5% tolerance over temperature (-40°C to +85°C). This value is defined by the "31" suffix in the part number and is verified per Table 2 (Threshold Suffix Guide) in the datasheet. The threshold remains stable with <0.5%VTH hysteresis, ensuring clean release without chatter during VCC recovery.

Does the MAX6864UK31D3L+T require external components for basic operation?

No, the MAX6864UK31D3L+T operates fully autonomously with no external components required. It includes an internal 10kΩ pullup on MR, precision bandgap reference, watchdog oscillator, and push-pull RESET driver. Only a 0.1µF VCC bypass capacitor is recommended for noise immunity - no resistors, capacitors, or additional ICs are needed for voltage monitoring, manual reset, or watchdog functionality.

How does the watchdog timer in the MAX6864UK31D3L+T clear and expire?

The MAX6864UK31D3L+T watchdog timer clears on *any* edge (rising or falling) at the WDI pin and expires only if WDI remains static (high or low) for longer than 209s (typical, L-suffix). It does not require alternating high/low pulses - a single edge suffices to reset the timer. During RESET assertion, the watchdog is paused; it resumes counting immediately upon RESET deassertion.

What is the guaranteed minimum reset timeout period for the MAX6864UK31D3L+T?

For the MAX6864UK31D3L+T, the reset timeout period is fixed at 150ms minimum (D3 suffix), with typical value 225ms and maximum 300ms across temperature and voltage. This timeout begins when VCC rises above 3.075V *and* MR is deasserted, and ensures the microprocessor has sufficient time to stabilize clocks and initialize peripherals before release.

Can the MAX6864UK31D3L+T operate reliably at VCC = 1.2V?

Yes, the MAX6864UK31D3L+T is fully specified to operate from VCC = 1.2V to 5.5V, and its RESET output is guaranteed valid down to VCC = 1.1V. At 1.2V, supply current is 190nA (typ), reset threshold remains 3.075V ±2.5%, and RESET output maintains VOL ≤ 0.3V at 50µA sink - enabling robust supervision in deep-brownout conditions common in aging batteries.