Analog Devices Inc./Maxim Integrated MAX6866UK43D3S+T

Overview

The MAX6866UK43D3S+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-low open-drain RESET output when VCC drops below 4.300V (typ), MR is pulled low, or the watchdog times out after 3.3s (typ). Designed for ultra-low-power systems, it draws only 170nA (typ) supply current and guarantees valid reset down to VCC = +1.1V - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6866UK43D3S+T datasheet, MAX6866UK43D3S+T pinout, MAX6866UK43D3S+T application, or MAX6866UK43D3S+T equivalent, this page delivers verified technical context, exact pin roles, confirmed reset threshold and timeout values, watchdog timing behavior, and two validated alternative parts with documented functional differences.

Technical Context

The MAX6866UK43D3S+T implements a precision bandgap-based voltage monitor with ±2.5% threshold accuracy over temperature, paired with a digitally timed watchdog that clears on any WDI edge and expires after 3.3s (typ) if inactive. Its internal 10kΩ MR pullup and glitch rejection (200ns) enable robust manual reset without external components.

This device uses a fixed 150ms (min) reset timeout period (D3 option), open-drain RESET output requiring external pullup, and operates across VCC = 1.2V to 5.5V. It is immune to VCC transients ≤40µs at 100mV overdrive and supports logic-level compatibility via configurable RESET termination.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount. Compact 2.9mm × 1.6mm footprint with 0.95mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK43D3S+T, the MAX6866UK43D3S+T's open-drain output enables shared reset busing and voltage translation, while TPS3838K33DBVR trades nanopower operation for lower unit cost and simpler qualification - making MAX6866UK43D3S+T optimal for safety-critical, long-life portable medical designs.

Availability

MAX6866UK43D3S+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, MP3 players, and smart wearables requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.

Supply support for MAX6866UK43D3S+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 high-performance analog and mixed-signal ICs for power, sensing, and interface applications in industrial, medical, and consumer markets.

The MAX6854–MAX6869 family delivers nanopower supervisory functionality targeting battery-operated portable electronics where ultra-low ICC, guaranteed reset validity down to 1.1V, and integrated watchdog are essential for safety and reliability.

FAQ

What is the exact reset threshold voltage of the MAX6866UK43D3S+T?

The MAX6866UK43D3S+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 VTH = 4.300V (min 4.193V, max 4.408V). The MAX6866UK43D3S+T maintains this accuracy across its full -40°C to +85°C operating range.

Does the MAX6866UK43D3S+T include a watchdog timer, and what is its timeout?

Yes, the MAX6866UK43D3S+T includes a watchdog timer with a nominal timeout of 3.3 seconds, indicated by the "S" suffix in the part number. The watchdog clears on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond this period. The MAX6866UK43D3S+T datasheet specifies min/typ/max values of 1.5s/3.3s/7.75s under varying conditions.

What does the "D3" in MAX6866UK43D3S+T signify?

The "D3" suffix in MAX6866UK43D3S+T denotes the reset timeout period option: 150ms (minimum), 225ms (typical), and 300ms (maximum). This is defined in Table 4 (Reset Timeout Periods) of the datasheet. The D3 selection ensures the RESET signal remains asserted long enough for complete µP initialization, especially in systems with slow clock startup or complex boot sequences.

Is the RESET output of the MAX6866UK43D3S+T push-pull or open-drain?

The MAX6866UK43D3S+T features an active-low open-drain RESET output, as confirmed in the Pin Description section (page 8) and Selector Guide (page 16). This requires an external pullup resistor and enables wired-OR configurations, voltage level translation, and multi-device reset bus sharing - a key differentiator from push-pull variants like MAX6864UK43D3S+T.

What is the supply current consumption of the MAX6866UK43D3S+T at 1.8V?

The MAX6866UK43D3S+T draws 170nA (typical) supply current at VCC = 1.8V, TA = +25°C, with reset deasserted - per Electrical Characteristics table (page 2). This ultra-low ICC enables multi-year operation in coin-cell-powered devices. At VCC < VTH (reset asserted), current rises to 7µA (typ), still negligible for most battery-life calculations.