Analog Devices Inc./Maxim Integrated MAX6869UK26D3S+T

Overview

The MAX6869UK26D3S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 2.625V reset threshold (suffix '26'), 150ms minimum reset timeout (suffix 'D3'), and watchdog timer with 3.3s typical timeout (suffix 'S'). It monitors VCC, responds to manual reset (MR), and triggers reset on watchdog timeout or brownout - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6869UK26D3S+T datasheet, MAX6869UK26D3S+T pinout, MAX6869UK26D3S+T application, or MAX6869UK26D3S+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), open-drain/push-pull output options, and compatibility with low-voltage µP systems operating from 1.2V to 5.5V.

Technical Context

This device integrates three core functions: precision voltage monitoring with ±2.5% threshold accuracy across -40°C to +85°C, a manual reset input with 250ns MR-to-reset delay and 1µs minimum pulse width, 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.

The internal architecture includes a bandgap reference, hysteresis-controlled comparator (0.5% VTH), reset timeout generator with six fixed options (D1–D6), and a noise-immune WDI input with 150ns pulse detection capability. All functions operate reliably with VCC as low as 1.2V, and the reset output remains valid down to 1.1V.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, footprint-compatible with industry-standard 5-pin SOT23.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6869UK26D3S+T, MAX6864UK26D3S+T offers simpler drive capability but sacrifices voltage-level flexibility, while TPS3836K26DBVR trades 10× higher quiescent current for broader TI support infrastructure - making MAX6869UK26D3S+T optimal for long-life, mixed-rail, watchdog-critical medical wearables.

Availability

MAX6869UK26D3S+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign loggers, industrial handheld scanners, and smart wearable health bands requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6869UK26D3S+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 MAX6854–MAX6869 family was designed specifically for ultra-low-power microprocessor supervision in battery-critical portable medical and consumer electronics, emphasizing nanoscale current draw, wide VCC range, and robust reset timing under brownout.

FAQ

What is the exact reset threshold voltage of the MAX6869UK26D3S+T?

The MAX6869UK26D3S+T has a factory-trimmed reset threshold of 2.625V, with ±2.5% tolerance over -40°C to +85°C. This value is confirmed by the '26' suffix in the part number per Maxim's Threshold Suffix Guide (Table 2), and is measured at VCC falling. The device guarantees reset assertion when VCC drops below this threshold and holds reset for the full D3 timeout period (150ms min) after VCC rises above it.

Does the MAX6869UK26D3S+T support open-drain reset output?

Yes, the MAX6869UK26D3S+T features an active-low open-drain RESET output on pin 4. This allows direct connection to µP reset inputs operating at different voltage levels (up to 5.5V) using an external pullup resistor. The output sinks up to 50µA at VCC ≥1.1V with VOL ≤0.3V, enabling interoperability with diverse logic families without level translators.

What is the watchdog timeout behavior of the MAX6869UK26D3S+T?

The MAX6869UK26D3S+T watchdog timer has a typical timeout of 3.3s (suffix 'S'), with a minimum of 1.5s and maximum of 7.75s. It clears on any rising or falling edge at WDI (pin 1) and expires only if WDI remains static beyond the timeout. During reset assertion, the watchdog is disabled; it resumes counting immediately upon reset deassertion - preventing false triggers during power transitions.

Can the MAX6869UK26D3S+T operate reliably at 1.2V supply?

Yes, the MAX6869UK26D3S+T is fully specified to operate from VCC = 1.2V to 5.5V. Its 170nA typical supply current is measured at 1.8V, but electrical characteristics including reset threshold accuracy, watchdog timing, and MR input thresholds remain valid across the entire 1.2V–5.5V range. Reset output is guaranteed functional down to VCC = 1.1V.

How does the MAX6869UK26D3S+T handle short VCC transients?

The MAX6869UK26D3S+T is immune to VCC transients ≤40µs in duration when the overdrive is 100mV (i.e., VCC dips 100mV below the 2.625V threshold). This immunity is characterized in the "Maximum VCC Transient Duration vs. Reset Threshold Overdrive" graph (Figure 5 in datasheet). Transients shorter than this limit will not trigger spurious resets, enhancing reliability in electrically noisy environments.