Analog Devices Inc./Maxim Integrated MAX6865UK20D3S+T

Overview

The MAX6865UK20D3S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 2.0V reset threshold (±2.5%), 300ms 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 MAX6865UK20D3S+T datasheet, MAX6865UK20D3S+T pinout, MAX6865UK20D3S+T application, or MAX6865UK20D3S+T equivalent, key selection criteria include guaranteed RESET validity down to VCC = +1.1V, immunity to sub-40µs VCC transients, pin-selectable reset delay absence (fixed D3 timeout), and compatibility with 1.2V–5.5V supply rails.

Technical Context

This device implements a precision bandgap-based voltage monitor with 0.5% hysteresis, a digital watchdog timer that clears on any WDI edge (min pulse width 150ns), and a fixed 300ms reset timeout after VCC recovery or MR deassertion. The internal 10kΩ MR pullup enables direct switch interfacing without external components.

RESET assertion occurs when VCC falls below 2.0V, MR is pulled low, or WDI remains static beyond 3.3s (typ). RESET remains high for ≥300ms after VCC exceeds 2.0V and MR releases, ensuring reliable µP initialization. No external timing capacitors or resistors are required.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount. Footprint compatible with industry-standard 5-pin SOT23 land pattern (JEDEC MO-178AA).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK20D3S+T, the MAX6865UK20D3S+T provides identical supervision accuracy and watchdog performance but delivers active-high RESET for direct µP compatibility - versus TPS3836K20DBVR, it reduces supply current by 99.99% and adds critical watchdog fault coverage.

Availability

MAX6865UK20D3S+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered IoT sensors, and industrial handheld equipment requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.

Supply support for MAX6865UK20D3S+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 communications markets.

The MAX6854–MAX6869 family delivers nanopower supervision for space-constrained, battery-critical systems - engineered specifically for multi-year operation in glucose monitors, wearables, and remote sensors.

FAQ

What is the reset threshold voltage of the MAX6865UK20D3S+T?

The MAX6865UK20D3S+T has a factory-trimmed reset threshold of 2.0V with ±2.5% tolerance over temperature. This value is fixed per the "20" suffix in the part number and is guaranteed valid from -40°C to +85°C. The device asserts RESET when VCC falls below this threshold and holds it asserted for ≥300ms after VCC rises above 2.0V.

Does the MAX6865UK20D3S+T include a watchdog timer?

Yes, the MAX6865UK20D3S+T includes a watchdog timer with a typical timeout of 3.3s (S-suffix), which expires if the WDI pin remains static (no rising or falling edge) beyond that period. The timer clears on every WDI transition, MR assertion, or RESET assertion - making it suitable for detecting firmware hangs in low-power embedded systems.

What type of RESET output does the MAX6865UK20D3S+T provide?

The MAX6865UK20D3S+T provides an active-high push-pull RESET output on Pin 1. Unlike open-drain variants, it does not require an external pullup resistor and can directly drive the reset input of most microcontrollers. Its VOH is guaranteed ≥0.8 × VCC when sourcing 500µA, supporting clean logic-level compatibility across 1.2V–5.5V supplies.

What is the supply current consumption of the MAX6865UK20D3S+T?

The MAX6865UK20D3S+T consumes only 170nA typical supply current at +25°C with VCC = 2.5V and no load - among the lowest in its class. This ultra-low ICC enables multi-year operation from small coin cells and is critical for always-on portable medical and sensor applications where battery replacement is impractical.

Is the MAX6865UK20D3S+T pin-compatible with other supervisory ICs?

The MAX6865UK20D3S+T uses a standard 5-pin SOT23-5 package and shares pinout compatibility with the MAX6864/MAX6866 series (Pin 1=RESET, Pin 2=GND, Pin 3=MR, Pin 4=WDI, Pin 5=VCC). It is not pin-compatible with TPS3836-series devices, which use different pin assignments and lack WDI functionality - PCB layout must match the MAX6865-specific pin mapping.