Analog Devices Inc./Maxim Integrated MAX6865UK45D2S+T

Overview

The MAX6865UK45D2S+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 4.500V reset threshold (±2.5%), 40ms minimum reset timeout, and integrated watchdog timer with 3.3s typical timeout. It monitors VCC, accepts manual reset (MR), and asserts active-high push-pull RESET during brownout, power-up, or watchdog expiration - used in battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK45D2S+T datasheet, MAX6865UK45D2S+T pinout, MAX6865UK45D2S+T application, or MAX6865UK45D2S+T equivalent, this page delivers verified electrical parameters, functional pin roles, real-world use cases, and validated alternative parts for low-power µP reset and watchdog supervision in space-constrained, long-life embedded systems.

Technical Context

The MAX6865UK45D2S+T implements a precision bandgap-based voltage monitor with 0.5% hysteresis, a digital watchdog timer that clears on any WDI edge (rising or falling) and expires if WDI remains static >3.3s (typ), and an internal 10kΩ MR pullup. Its reset assertion logic combines VCC monitoring, MR input, and watchdog status via OR-gated internal logic.

It guarantees valid RESET output down to VCC = +1.1V, tolerates VCC transients ≤40µs at 100mV overdrive, and requires no external components. The active-high push-pull RESET output sources up to 500µA at VCC ≥ 2.38V while maintaining VOH ≥ 0.8×VCC.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, 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 MAX6865UK45D2S+T, MAX6864UK45D2S+T offers identical supervision but requires external biasing for RESET, while TPS3837K33DBVR trades ultra-low power and watchdog capability for simpler architecture and higher ICC - making MAX6865UK45D2S+T optimal for compact, long-life, safety-critical portable medical designs.

Availability

MAX6865UK45D2S+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered instrumentation, and industrial handhelds requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.

Supply support for MAX6865UK45D2S+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 industrial, medical, and communications applications.

The MAX68xx family delivers nanopower supervisory solutions optimized for battery longevity and reliability in portable healthcare and IoT edge devices - combining voltage monitoring, manual reset, and watchdog functions in minimal footprints.

FAQ

What is the exact reset threshold voltage of the MAX6865UK45D2S+T?

The MAX6865UK45D2S+T has a factory-trimmed reset threshold of +4.500V, with guaranteed tolerance of ±2.5% over the -40°C to +85°C temperature range. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "45" corresponds to 4.500V nominal. The MAX6865UK45D2S+T maintains this accuracy without external calibration.

Does the MAX6865UK45D2S+T require external components for basic operation?

No, the MAX6865UK45D2S+T operates autonomously with zero external components for core supervision. Only a 0.1µF ceramic bypass capacitor on VCC to GND is recommended for noise immunity. The MR input features an internal 10kΩ pullup, and the active-high push-pull RESET eliminates need for external pull resistors - simplifying design and reducing BOM count.

How does the watchdog timer in the MAX6865UK45D2S+T respond to software activity?

The MAX6865UK45D2S+T watchdog timer clears on any detected edge (rising or falling) at the WDI pin and expires only if WDI remains static for >3.3s (typ). Unlike edge-counting watchdogs, it does not require toggling - a single transition suffices. This allows flexible placement of WDI updates in firmware, such as setting WDI high at startup and low before critical subroutines, as documented in Figure 6 of the datasheet.

What is the minimum VCC voltage at which the MAX6865UK45D2S+T guarantees valid RESET output?

The MAX6865UK45D2S+T guarantees RESET output validity down to VCC = +1.1V, as specified in the Absolute Maximum Ratings and Electrical Characteristics tables. This ensures deterministic reset assertion even during severe brownout conditions, unlike many supervisors that fail below 1.5V. The guarantee applies to both reset assertion and deassertion behavior across the full operating temperature range.

Is the MAX6865UK45D2S+T pin-compatible with other devices in the MAX68xx family?

Yes, the MAX6865UK45D2S+T shares the same 5-pin SOT23-5 pinout as all MAX6864–MAX6869 variants, including identical pin assignments for VCC, GND, MR, WDI, and RESET. However, RESET polarity and type (push-pull vs. open-drain) vary across the family - MAX6865UK45D2S+T uses active-high push-pull, while MAX6864UK45D2S+T uses active-low open-drain, requiring schematic review before substitution.