Analog Devices Inc./Maxim Integrated MAX6865UK43D3S+T

Overview

The MAX6865UK43D3S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring (4.300V factory-trimmed reset threshold), manual reset input (MR), and watchdog timer (209s typical timeout) with ultra-low 170nA typical supply current. It asserts an active-high push-pull RESET output during VCC brownout, MR assertion, or watchdog timeout, ensuring reliable µP initialization in battery-constrained medical and portable systems.

For engineers reviewing the MAX6865UK43D3S+T datasheet, MAX6865UK43D3S+T pinout, MAX6865UK43D3S+T application, or MAX6865UK43D3S+T equivalent, this page delivers verified specifications including reset threshold tolerance (±2.5%), guaranteed reset validity down to VCC = +1.1V, six selectable reset timeout options (10ms–1200ms), and watchdog immunity to short VCC transients - all critical for low-power embedded system reliability validation.

Technical Context

The MAX6865UK43D3S+T 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 (rising or falling) and expires if WDI remains static beyond 209s (typ). Its internal 10kΩ MR pullup and glitch rejection (200ns) enable robust manual reset without external components.

Reset assertion is latched and held for the full timeout period (D3 = 150ms min) after VCC exceeds threshold or MR deasserts; the active-high push-pull RESET output drives to ≥0.8×VCC when deasserted and ≤0.3V when asserted under specified load conditions, eliminating need for external level-shifting in most µP interfaces.

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 MAX6864UK43D3S+T and TPS3837K33DBVR, the MAX6865UK43D3S+T uniquely delivers active-high reset signaling, 209s watchdog supervision, and 170nA supply current in one 5-pin SOT23 device - enabling compact, long-life, fail-safe operation in regulated medical and portable electronics.

Availability

MAX6865UK43D3S+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, MP3 players, and feature cell phones requiring stable component supply across extended product lifecycles and temperature ranges (-40°C to +85°C).

Supply support for MAX6865UK43D3S+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, sensing, and interface applications in industrial, medical, and consumer markets.

The MAX6854–MAX6869 family was engineered specifically for nanopower microprocessor supervision in battery-operated medical and portable devices, integrating voltage monitoring, manual reset, and watchdog functions into minimal-area SOT23 packages.

FAQ

What is the exact reset threshold voltage of the MAX6865UK43D3S+T?

The MAX6865UK43D3S+T has a factory-trimmed reset threshold of 4.300V with ±2.5% tolerance over -40°C to +85°C, as defined by the "43" suffix per Maxim's Threshold Suffix Guide. This value is laser-trimmed during production and does not require external calibration. The MAX6865UK43D3S+T guarantees reset assertion when VCC falls below this threshold and holds reset for the D3 timeout period (150ms min) after VCC recovers.

Does the MAX6865UK43D3S+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK43D3S+T includes a watchdog timer with a typical timeout of 209s, denoted by the "S" suffix in the part number. The timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond this period. The MAX6865UK43D3S+T asserts RESET for the full D3 timeout (150ms min) upon watchdog expiration, providing robust runtime firmware supervision.

What type of reset output does the MAX6865UK43D3S+T provide?

The MAX6865UK43D3S+T provides an active-high push-pull RESET output (Pin 1), meaning it drives high during reset assertion and low when deasserted. This eliminates the need for an external pullup resistor and simplifies interfacing with µPs that accept active-high reset signals. The MAX6865UK43D3S+T output meets VOH ≥0.8×VCC and VOL ≤0.3V under specified load conditions, ensuring reliable logic-level compatibility.

What is the supply current of the MAX6865UK43D3S+T, and how does it vary with voltage?

The MAX6865UK43D3S+T draws 170nA typical supply current at VCC = 1.8V, 190nA at 3.3V, and 210nA at 5.0V, as specified in the Electrical Characteristics table. This ultra-low ICC remains stable across temperature (-40°C to +85°C) and enables multi-year operation from coin cells. The MAX6865UK43D3S+T achieves this efficiency via BiCMOS process optimization and dynamic current scaling, with no increase in quiescent draw during watchdog operation.

Is the MAX6865UK43D3S+T pin-compatible with other supervisory ICs?

The MAX6865UK43D3S+T is pin-compatible with the MAX6864–MAX6869 family in the 5-pin SOT23 package but differs from MAX6854–MAX6863 series in WDI placement (Pin 4 vs CT/MR variants). It is not pin-compatible with TPS3836/TPS3837/TPS3838 due to different pin assignments and reset polarity. The MAX6865UK43D3S+T shares identical footprint and solder pad layout with MAX6864UK43D3S+T, allowing direct substitution where active-high reset is required.