Analog Devices Inc./Maxim Integrated MAX6865UK27D2S+T

Overview

The MAX6865UK27D2S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, combining voltage monitoring (2.700V reset threshold), manual reset input (MR), and watchdog timer (3.3s timeout) with ultra-low 170nA typical supply current. It asserts an active-low push-pull RESET output during VCC brownout, MR assertion, or watchdog timeout, and holds reset for 40ms minimum after recovery - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK27D2S+T datasheet, MAX6865UK27D2S+T pinout, MAX6865UK27D2S+T application, or MAX6865UK27D2S+T equivalent, key selection criteria include its 2.700V factory-trimmed threshold, 40ms reset timeout, 3.3s watchdog period, guaranteed RESET validity down to VCC = +1.1V, and immunity to sub-40µs VCC transients.

Technical Context

This device implements a precision bandgap-based voltage monitor with ±2.5% threshold accuracy over -40°C to +85°C, coupled with a digital watchdog timer that clears on any WDI edge and expires if WDI remains static beyond 3.3s (typ). The internal reset timeout generator uses RC-based timing with temperature-compensated stability.

The MR input features 10kΩ internal pullup, 1µs minimum pulse width support, and 200ns glitch rejection; RESET output delivers push-pull active-low drive with VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.12V) and VOH ≥ 0.8×VCC at ISOURCE = 500µA.

Key Specifications

Pinout & Package

5-pin SOT23 package (lead-free, RoHS-compliant) with 1.3mm × 2.9mm footprint and 0.95mm height - compatible with standard high-volume pick-and-place assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK27D2S+T, MAX6326UR29+T omits watchdog capability but offers longer reset timeout, while TPS3836K33DBVR trades 20× higher ICC for TI's production scalability - neither provides the 2.700V/3.3s/40ms combination critical for portable medical reset integrity.

Availability

MAX6865UK27D2S+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered diagnostics equipment, and implantable telemetry modules requiring stable component supply with long-term lifecycle assurance.

Supply support for MAX6865UK27D2S+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 demanding applications in healthcare, industrial, and communications markets.

The MAX68xx family targets ultra-low-power microprocessor supervision in space-constrained, battery-operated systems - emphasizing nanopower operation, factory-trimmed accuracy, and integrated watchdog functionality for functional safety.

FAQ

What is the exact reset threshold voltage of the MAX6865UK27D2S+T?

The MAX6865UK27D2S+T has a factory-trimmed reset threshold of 2.700V 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 "27" corresponds to VTH = 2.700V. The device guarantees valid RESET assertion down to VCC = +1.1V, making it suitable for deep-brownout scenarios in MAX6865UK27D2S+T-based medical sensors.

Does the MAX6865UK27D2S+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK27D2S+T integrates a watchdog timer with a typical timeout period of 3.3 seconds, denoted by the "S" suffix in the part number. The timer clears on any rising or falling edge at the WDI pin and expires if WDI remains static beyond this period, triggering a reset for the configured 40ms timeout. This behavior is specified in Table 3 (Watchdog Timeout) and applies exclusively to MAX6864–MAX6869 variants like the MAX6865UK27D2S+T.

What is the reset timeout period for the MAX6865UK27D2S+T, and how is it selected?

The MAX6865UK27D2S+T has a fixed reset timeout period of 40ms (minimum), indicated by the "D2" suffix per Table 4 (Reset Timeout Periods). Unlike MAX6861–MAX6863 variants, this parameter is factory-set and not user-configurable. The 40ms duration ensures sufficient hold time for ARM Cortex-M and similar µPs to complete internal initialization before releasing RESET - a key timing requirement validated in MAX6865UK27D2S+T application circuits.

What package type and lead finish does the MAX6865UK27D2S+T use?

The MAX6865UK27D2S+T is supplied in a 5-pin SOT23-5 package with lead-free (RoHS-compliant) finish, as indicated by the "+T" suffix. Its dimensions are 1.3mm × 2.9mm × 0.95mm, compatible with standard high-speed placement equipment. The package includes exposed pad thermal enhancement and meets JEDEC MO-178 standards - identical to other MAX68xx supervisory devices for seamless board-level substitution.

How does the MAX6865UK27D2S+T handle short VCC transients, and what is its immunity level?

The MAX6865UK27D2S+T is immune to VCC transients ≤40µs in duration when the overdrive is 100mV above its 2.700V threshold, as shown in Figure MAX684 toc05. This transient immunity prevents false resets caused by switching noise or RF coupling in portable medical devices. The design achieves this through internal filtering and hysteresis (0.5% of VTH), ensuring robust operation in MAX6865UK27D2S+T deployments near wireless transceivers or motor drivers.