Analog Devices Inc./Maxim Integrated MAX6864UK20D4S+T

Overview

The MAX6864UK20D4S+T 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 2.0V reset threshold (±2.5%), 1200ms minimum reset timeout, and a 3.3s typical watchdog timeout. It monitors VCC, accepts manual reset via MR input, and triggers reset on voltage drop, MR assertion, or watchdog expiration - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6864UK20D4S+T datasheet, MAX6864UK20D4S+T pinout, MAX6864UK20D4S+T application, or MAX6864UK20D4S+T equivalent, this page delivers verified technical context, exact pin functions, real-world timing behavior, and validated alternative options for low-power embedded reset supervision.

Technical Context

The MAX6864UK20D4S+T integrates three core supervision functions: precision VCC monitoring with guaranteed reset validity down to VCC = +1.1V, edge-triggered manual reset with 250ns MR-to-reset delay and 1µs minimum pulse width, and a watchdog timer that clears on any WDI transition (rising or falling) and expires after 3.3s (typ) if inactive.

Its internal architecture includes a bandgap-based voltage reference, a hysteresis-controlled comparator (0.5% VTH), a digital timeout counter for reset assertion, and a state machine that prioritizes reset sources - VCC drop, MR, or watchdog timeout - with no external components required.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, 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 MAX6865UK20D4S+T, the MAX6864UK20D4S+T provides active-low reset compatibility with legacy µPs, while TPS3836K20DBVR trades 10× higher quiescent current for broader distributor availability and simpler qualification - making it viable for non-battery-critical industrial controls.

Availability

MAX6864UK20D4S+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered wearables, smart hearing aids, and industrial handheld scanners requiring stable component supply across long product lifecycles.

Supply support for MAX6864UK20D4S+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 management, sensing, and interface applications in demanding environments.

The MAX6864UK20D4S+T belongs to the nanopower µP supervisory family, engineered specifically for ultra-low-power, safety-critical portable electronics where battery life, reset reliability, and watchdog integrity are non-negotiable.

FAQ

What is the exact reset threshold voltage of the MAX6864UK20D4S+T?

The MAX6864UK20D4S+T has a factory-trimmed reset threshold of 2.0V with ±2.5% tolerance over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "20" corresponds to VTH = 2.000V (typ). The device guarantees valid reset assertion down to VCC = +1.1V, independent of threshold accuracy.

Does the MAX6864UK20D4S+T require external components for basic operation?

No, the MAX6864UK20D4S+T requires no external components for core supervision. Its internal 10kΩ MR pull-up, precision voltage reference, and digital timeout logic eliminate need for resistors or capacitors. Only a 0.1µF ceramic bypass capacitor on VCC is recommended for noise immunity - not mandatory but strongly advised per datasheet Figure 1.

How does the watchdog timer in the MAX6864UK20D4S+T respond to firmware activity?

The MAX6864UK20D4S+T watchdog timer clears on any rising or falling edge at the WDI pin and expires after 3.3s (typ) if no edge occurs. It ignores pulse width or duty cycle - only edge transitions matter. The timer remains suspended while RESET is asserted, resuming counting immediately upon deassertion, enabling robust integration with interrupt-driven or polling-based firmware.

What is the function of Pin 1 (RESET) on the MAX6864UK20D4S+T?

Pin 1 of the MAX6864UK20D4S+T is the active-low push-pull RESET output. It drives low during VCC brownout, MR assertion, or watchdog timeout, and remains low for the full 1200ms timeout period before returning high. Unlike open-drain variants, it does not require an external pull-up and can sink 500µA at VCC ≥ 2.38V - directly compatible with most µP reset inputs.

Is the MAX6864UK20D4S+T pin-compatible with other devices in the MAX68xx family?

Yes, the MAX6864UK20D4S+T shares the identical 5-pin SOT23-5 pinout with all MAX6854–MAX6869 variants, including MAX6865UK20D4S+T and MAX6866UK20D4S+T. Pin assignments (RESET, GND, MR, WDI, VCC) are fixed across the family - enabling direct substitution where reset polarity and feature set align.