Analog Devices Inc./Maxim Integrated MAX6865UK34D1S+T

Overview

The MAX6865UK34D1S+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 3.315V reset threshold (suffix "34"), 10ms minimum reset timeout (suffix "D1"), and integrated watchdog timer with 3.3s typical timeout (suffix "S"). It monitors VCC, responds to manual reset (MR), and asserts reset on voltage drop, MR assertion, or watchdog expiration - used in battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK34D1S+T datasheet, MAX6865UK34D1S+T pinout, MAX6865UK34D1S+T application, or MAX6865UK34D1S+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), push-pull active-low reset output, and compatibility with noisy low-power systems requiring precise brownout detection and software fault recovery.

Technical Context

The MAX6865UK34D1S+T implements a dual-monitoring architecture: a precision bandgap-based voltage detector for VCC monitoring with ±2.5% threshold accuracy and 0.5% hysteresis, and an RC-based watchdog timer that clears on any WDI edge and expires if WDI remains static beyond 3.3s (typ). Its internal 10kΩ MR pullup enables direct switch interfacing without external components.

Reset assertion is latched and held for the full 10ms timeout after VCC rises above 3.315V and MR deasserts; the push-pull RESET output drives actively low (VOL ≤ 0.3V at 1.2mA) and high (VOH ≥ 0.8×VCC) with no external pullup required. The device operates across -40°C to +85°C and draws only 170nA at 2.5V, enabling multi-year operation on coin-cell batteries.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK34D1S+T, the MAX6865UK34D1S+T adds no functional overhead but retains identical core supervision - while TPS3836K33DBVR trades nanopower operation and watchdog capability for simpler qualification in legacy 3.3V-only systems.

Availability

MAX6865UK34D1S+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign recorders, industrial handheld scanners, and low-power wearable sensors requiring stable component supply across extended production lifecycles.

Supply support for MAX6865UK34D1S+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 industrial, medical, and automotive markets.

The MAX6865UK34D1S+T belongs to the MAX68xx nanopower supervisory family, engineered specifically for battery-critical portable medical and IoT devices demanding sub-µA quiescent current, guaranteed low-VCC reset, and integrated watchdog reliability.

FAQ

What is the exact reset threshold voltage of the MAX6865UK34D1S+T?

The MAX6865UK34D1S+T has a factory-trimmed reset threshold of 3.315V, with ±2.5% tolerance over -40°C to +85°C. This value is defined by the "34" suffix in the part number and is verified per Table 2 (Threshold Suffix Guide) in the datasheet. The threshold remains stable across temperature, with normalized variation ≤±0.5% from -40°C to +85°C.

Does the MAX6865UK34D1S+T require external components for basic operation?

No, the MAX6865UK34D1S+T operates autonomously with no external components required: it features an internal 10kΩ pullup on MR, no timing capacitor for reset timeout, and a push-pull RESET output eliminating external pullups. Only a 0.1µF ceramic bypass capacitor on VCC to GND is recommended for noise immunity - not mandatory but strongly advised for robust operation.

How does the watchdog timer in the MAX6865UK34D1S+T respond to firmware activity?

The MAX6865UK34D1S+T watchdog timer clears on every rising or falling edge at the WDI pin and expires only if WDI remains static for ≥3.3s (typ). It ignores pulse widths <150ns and continues counting only when RESET is deasserted - ensuring reliable detection of hung firmware loops while tolerating brief signal glitches during normal operation.

Can the MAX6865UK34D1S+T assert reset when VCC drops below 1.5V?

Yes - the MAX6865UK34D1S+T guarantees valid RESET assertion down to VCC = +1.1V, well below 1.5V. At VCC = 1.2V, it maintains full reset functionality including MR response and watchdog expiration, with VOL ≤ 0.3V (at ISINK = 50µA) and VOH ≥ 0.8×VCC. This ensures fail-safe behavior during deep brownout conditions common in battery-powered systems.

Is the MAX6865UK34D1S+T pin-compatible with other MAX68xx devices?

The MAX6865UK34D1S+T uses the standard 5-pin SOT23-5 package and shares identical pinout (RESET, GND, MR, WDI, VCC) with MAX6864/MAX6866/MAX6867–MAX6869 variants. It is not pin-compatible with MAX6861–MAX6863 (which use CT instead of WDI) or MAX6854–MAX6856 (which lack WDI). Always verify pin function mapping against the specific variant's Pin Description table.