Analog Devices Inc./Maxim Integrated MAX6865UK22D3L+T

Overview

The MAX6865UK22D3L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, a factory-trimmed 2.235V reset threshold (suffix "22"), 150ms minimum reset timeout (suffix "D3"), and a 209s typical watchdog timeout (suffix "L"). It monitors VCC, responds to manual reset (MR) assertion, and triggers reset upon watchdog timer expiration - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK22D3L+T datasheet, MAX6865UK22D3L+T pinout, MAX6865UK22D3L+T application, or MAX6865UK22D3L+T equivalent, this page delivers verified technical context, exact pin functions, real-world timing behavior, and validated alternative options for low-power embedded system design and long-life portable equipment.

Technical Context

The MAX6865UK22D3L+T integrates voltage monitoring, a manual reset input (MR), and a watchdog timer with 209s typical timeout (L-suffix). Its internal watchdog clears on any WDI edge and expires only if WDI remains static beyond the timeout period - enabling robust software execution monitoring in safety-critical wearables.

This device asserts an active-high push-pull RESET output when VCC drops below 2.235V, MR is pulled low, or the watchdog expires. RESET remains high for ≥150ms after recovery, with guaranteed validity down to VCC = 1.1V and immunity to ≤40µs VCC transients at 100mV overdrive.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, -40°C to +85°C operating range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK22D3L+T, MAX6864UK22D3L+T offers identical supervision timing but inverted reset polarity, while TPS3836K22DBVR trades off watchdog capability and nanopower operation for lower unit cost in non-critical applications.

Availability

MAX6865UK22D3L+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered wearables, and industrial handheld scanners requiring stable component supply across extended product lifecycles.

Supply support for MAX6865UK22D3L+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 connectivity in demanding environments.

The MAX68xx family delivers nanopower supervision for battery-constrained systems, with emphasis on medical, portable, and safety-aware applications where reliability and ultra-low ICC are critical.

FAQ

What is the exact reset threshold voltage of the MAX6865UK22D3L+T?

The MAX6865UK22D3L+T has a factory-trimmed reset threshold of 2.235V, with ±2.5% tolerance over temperature. This value is defined by the "22" suffix in the part number and is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet. The device asserts RESET when VCC falls below this threshold and holds it for ≥150ms after VCC rises above it.

Does the MAX6865UK22D3L+T require external components for basic operation?

No, the MAX6865UK22D3L+T operates autonomously with no external resistors or capacitors required for core supervision. A 0.1µF ceramic bypass capacitor on VCC is recommended for noise immunity but is not strictly required for functionality. The MR input includes a 10kΩ internal pullup, and the active-high push-pull RESET eliminates need for external pullup resistors.

How does the watchdog timer in the MAX6865UK22D3L+T behave during reset assertion?

While RESET is asserted (high), the MAX6865UK22D3L+T's internal watchdog timer is disabled and does not count. The timer resumes counting only after RESET deasserts. This ensures that watchdog monitoring begins only after the µP has fully restarted and entered its main firmware loop - preventing premature timeout during boot sequences.

Can the MAX6865UK22D3L+T monitor supply voltages below 1.2V?

No - the MAX6865UK22D3L+T specifies a minimum operating VCC of 1.2V per Absolute Maximum Ratings and Electrical Characteristics tables. Although RESET remains valid down to VCC = 1.1V, the device is not guaranteed to function correctly or assert reset reliably below 1.2V. For sub-1.2V rails, consider dedicated ultra-low-voltage supervisors like the MAX6361 series.

What is the meaning of the "L" suffix in MAX6865UK22D3L+T?

The "L" suffix in MAX6865UK22D3L+T denotes the watchdog timeout option: 95s (min), 209s (typ), 487s (max). This distinguishes it from the "S" option (1.5s/3.3s/7.75s). The L-suffix enables long-duration firmware health checks - essential for applications like patient monitors where infrequent but critical background tasks must complete within the watchdog window.