Analog Devices Inc./Maxim Integrated MAX6865UK22D5L+T

Overview

The MAX6865UK22D5L+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 2.235V (factory-trimmed threshold), MR is pulled low, or the watchdog times out after 209s (typ). Designed for ultra-low-power systems, it draws only 170nA (typ) supply current and guarantees valid reset operation down to VCC = +1.1V - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK22D5L+T datasheet, MAX6865UK22D5L+T pinout, MAX6865UK22D5L+T application, or MAX6865UK22D5L+T equivalent, key selection criteria include its 2.235V reset threshold, 300ms minimum reset timeout (D5), 209s watchdog period (L suffix), active-high push-pull RESET output, and guaranteed operation at VCC ≥ 1.1V in -40°C to +85°C environments.

Technical Context

This device implements a precision bandgap-based voltage monitor with 2.5% threshold accuracy and 0.5% hysteresis, paired with a digitally controlled watchdog timer that clears on any WDI edge (rising or falling) and expires if WDI remains static >209s (typ). The internal 10kΩ MR pullup enables direct CMOS-level manual reset initiation without external components.

The reset logic combines three independent assertion sources - VCC undervoltage, MR assertion, and watchdog timeout - with priority-independent deassertion timing governed by a fixed 300ms (min) timeout after all conditions clear. Its BiCMOS process ensures immunity to short VCC transients (<40µs at 100mV overdrive) and stable operation across full industrial temperature range.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK22D5L+T, MAX6864UK22D5L+T offers identical supervision parameters but inverted RESET polarity, while TPS3837K22DBVR trades nanopower operation and watchdog functionality for lower cost and simpler architecture - making MAX6865UK22D5L+T the sole choice for battery-critical, watchdog-dependent medical designs.

Availability

MAX6865UK22D5L+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered instrumentation, and industrial handheld equipment requiring stable component supply with long-term lifecycle assurance.

Supply support for MAX6865UK22D5L+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 MAX68xx family delivers nanopower supervisory solutions optimized for battery longevity and reliability in portable healthcare and IoT edge devices - with the MAX6865UK22D5L+T targeting applications demanding both precise voltage monitoring and long-interval watchdog supervision.

FAQ

What is the exact reset threshold voltage of the MAX6865UK22D5L+T?

The MAX6865UK22D5L+T has a factory-trimmed reset threshold of 2.235V, with ±2.5% tolerance over temperature (-40°C to +85°C). This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "22" corresponds to 2.235V nominal. The device guarantees valid reset assertion down to VCC = +1.1V, ensuring robustness during deep brownout conditions.

Does the MAX6865UK22D5L+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK22D5L+T includes a watchdog timer with a typical timeout period of 209 seconds, indicated by the "L" 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 interval. This long timeout is specifically designed for low-duty-cycle systems like remote patient monitors where firmware health checks occur infrequently but must be highly reliable.

What type of RESET output does the MAX6865UK22D5L+T provide, and how is it configured?

The MAX6865UK22D5L+T provides an active-high push-pull RESET output, as confirmed by its pin description (Pin 1 = RESET, active-high push-pull) and Selector Guide. This configuration eliminates the need for an external pullup resistor and ensures strong logic-level drive into the µP's reset input across the full 1.2V–5.5V VCC range, with VOH ≥ 0.8×VCC and VOL ≤ 0.3V under specified load conditions.

What is the reset timeout period for the MAX6865UK22D5L+T, and how is it selected?

The MAX6865UK22D5L+T has a fixed minimum reset timeout period of 300ms, designated by the "D5" suffix per Table 4 (Reset Timeout Periods). This value is factory-programmed and non-adjustable - unlike the MAX6861–MAX6863 series, which use the CT pin for selection. The 300ms duration ensures sufficient time for complete µP power-up sequencing, PLL locking, and memory initialization before release.

Is the MAX6865UK22D5L+T compatible with standard SOT23-5 footprints and assembly processes?

Yes, the MAX6865UK22D5L+T uses a standard 5-pin SOT23-5 package with JEDEC MO-178AC outline, fully compatible with automated pick-and-place and reflow soldering. Its lead-free "+T" suffix confirms RoHS-compliant termination, and the pinout (GND at Pin 2, VCC at Pin 5) matches industry-standard SOT23 orientation. Thermal and mechanical data confirm suitability for standard IPC-7351B land patterns.