Analog Devices Inc./Maxim Integrated MAX6865UK43D4S+T

Overview

The MAX6865UK43D4S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring, manual reset input (MR), and watchdog timer (WDI) functions. It asserts an active-high push-pull RESET output when VCC drops below 4.300V (typ), MR is pulled low, or the watchdog expires after 3.3s (typ). Designed for ultra-low-power systems, it draws only 170nA (typ) supply current and guarantees valid reset operation down to VCC = +1.1V.

For engineers reviewing the MAX6865UK43D4S+T datasheet, MAX6865UK43D4S+T pinout, MAX6865UK43D4S+T application, or MAX6865UK43D4S+T equivalent, this device is selected for battery-powered medical monitors, portable instrumentation, and embedded systems requiring guaranteed brownout immunity, glitch-resistant reset timing, and software-failure detection via watchdog timeout.

Technical Context

The MAX6865UK43D4S+T implements a dual-threshold voltage monitor with ±2.5% accuracy over temperature, coupled to a monolithic watchdog timer that clears on any WDI edge and times out after 3.3s (typ) if inactive. Its internal 10kΩ MR pullup enables direct switch interface without external components.

Reset assertion is synchronized to VCC crossing the factory-trimmed 4.300V threshold, with a fixed 1200ms (min) timeout period after recovery. The active-high push-pull RESET output drives directly into CMOS inputs and remains valid down to VCC = +1.1V, eliminating need for external level-shifting or pulldown resistors in most applications.

Key Specifications

Pinout & Package

MAX6865UK43D4S+T is housed in a lead-free 5-pin SOT23-5 package (JEDEC MO-178AA), with 0.95mm pitch and 2.9mm × 1.6mm footprint. Pin 1 is marked with a dot; pin numbering follows standard SOT23 convention (counterclockwise from mark).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3837K33DBVR and MAX6361KA29D3+T, the MAX6865UK43D4S+T uniquely delivers 4.3V precision monitoring, integrated watchdog with 3.3s timeout, and nanopower operation - making it the only option for long-life, safety-critical 4.3V battery systems requiring both voltage and software fault detection.

Availability

MAX6865UK43D4S+T is available at Aetrix Electronics and suitable for portable medical monitoring, battery-powered instrumentation, wearable health sensors, and industrial edge nodes requiring stable component supply across extended product lifecycles.

Supply support for MAX6865UK43D4S+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 MAX6865UK43D4S+T belongs to Maxim's nanopower µP supervisory family, engineered specifically for battery-constrained systems needing guaranteed reset integrity, ultra-low ICC, and integrated watchdog supervision without external components.

FAQ

What is the exact reset threshold voltage of the MAX6865UK43D4S+T?

The MAX6865UK43D4S+T has a factory-trimmed reset threshold of 4.300V (typical), with ±2.5% tolerance over temperature and supply voltage. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "43" corresponds to 4.300V. The device guarantees valid reset assertion down to VCC = +1.1V, making it suitable for applications with steep battery discharge curves.

Does the MAX6865UK43D4S+T require external components for basic operation?

No, the MAX6865UK43D4S+T requires no external components for core functionality. It integrates a 10kΩ internal pullup on the MR pin, needs no timing capacitors, and its active-high push-pull RESET output drives µP reset inputs directly. Only a 0.1µF ceramic bypass capacitor on VCC to GND is recommended for noise immunity - no resistors, diodes, or additional ICs are needed.

What is the watchdog timeout behavior of the MAX6865UK43D4S+T?

The MAX6865UK43D4S+T features a watchdog timer with a typical timeout of 3.3s (S-suffix), as specified in Table 3. The timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static (high or low) beyond that period. When it expires, it triggers the RESET output for the full 1200ms timeout - identical to voltage- or MR-initiated resets.

How does the MAX6865UK43D4S+T handle short VCC transients?

The MAX6865UK43D4S+T is designed to ignore short VCC transients: a 100mV dip in supply voltage lasting ≤40µs will not cause a false reset. This immunity is characterized in the "Maximum VCC Transient Duration vs. Reset Threshold Overdrive" graph (Figure 5). The device uses internal filtering and hysteresis (0.5% of VTH) to reject noise while maintaining fast response to genuine brownouts.

Is the MAX6865UK43D4S+T pin-compatible with other devices in the MAX68xx family?

The MAX6865UK43D4S+T shares the same 5-pin SOT23-5 package and pinout (RESET, GND, MR, WDI, VCC) with MAX6864–MAX6866 variants, but differs from MAX6861–MAX6863 (which use CT instead of WDI) and MAX6854–MAX6856 (which lack WDI). It is not pin-compatible with TPS3836/TPS3837 series, which have different pin assignments and no WDI function.