Analog Devices Inc./Maxim Integrated MAX6865UK33D1L+T

Overview

The MAX6865UK33D1L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, combining voltage monitoring (3.3V reset threshold), manual reset input (MR), and watchdog timer (209s typical timeout) with ultra-low 170nA supply current. It asserts an active-high push-pull RESET signal during VCC brownout, MR assertion, or watchdog timeout, and holds reset for 10ms minimum after recovery - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK33D1L+T datasheet, MAX6865UK33D1L+T pinout, MAX6865UK33D1L+T application, or MAX6865UK33D1L+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), pin-selectable reset timeout options, and compatibility with low-voltage µP systems requiring long battery life and robust fault recovery.

Technical Context

This device integrates a precision voltage monitor with factory-trimmed 3.3V reset threshold (±2.5%), a 209s typical watchdog timer that clears on WDI edge transitions, and a manual reset input with 250ns MR-to-reset delay and 1µs minimum pulse width. Its BiCMOS process enables stable operation across -40°C to +85°C while maintaining sub-µA quiescent current.

The active-high push-pull RESET output delivers VOH ≥ 0.8×VCC (at ISOURCE = 500µA) and VOL ≤ 0.3V (at ISINK = 1.2mA), ensuring reliable logic-level compatibility with modern low-voltage microcontrollers. Internal 10kΩ MR pullup eliminates external components, and the WDI input accepts pulses as short as 150ns.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount. Compact footprint (2.9mm × 1.6mm × 1.1mm) suitable for space-constrained portable electronics.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK33D1L+T, the MAX6865UK33D1L+T offers identical core supervision but belongs to a variant group with MR and WDI support - whereas TPS3836K33DBVR trades watchdog capability and ultra-low current for lower cost and broader availability, at the expense of battery life and fault coverage.

Availability

MAX6865UK33D1L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign loggers, and handheld diagnostic tools requiring stable component supply, long-term lifecycle support, and RoHS-compliant lead-free packaging.

Supply support for MAX6865UK33D1L+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 industrial, medical, and communications applications, emphasizing low-power, high-reliability performance.

The MAX6865UK33D1L+T belongs to the MAX68xx nanopower µP supervisory family, engineered specifically for battery-critical portable medical and consumer electronics where extended runtime and deterministic fault recovery are mandatory.

FAQ

What is the exact reset threshold voltage of the MAX6865UK33D1L+T?

The MAX6865UK33D1L+T has a factory-trimmed reset threshold of 3.300V, with tolerance of ±2.5% over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "33" corresponds to 3.3V nominal. The device guarantees valid reset assertion down to VCC = +1.1V, making it suitable for deep brownout detection in low-voltage systems.

Does the MAX6865UK33D1L+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK33D1L+T includes a watchdog timer with a typical timeout period of 209 seconds, denoted by the "L" suffix in the part number. This is verified in Table 3 (Watchdog Timeout) and Ordering Information, where "L" specifies the long timeout option (min 95s, typ 209s, max 487s). The timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond this interval.

What type of RESET output does the MAX6865UK33D1L+T provide, and how is it configured?

The MAX6865UK33D1L+T provides an active-high push-pull RESET output, confirmed in the Pin Description section for MAX6865 (pin 1 = RESET, active-high push-pull). This configuration eliminates the need for an external pullup resistor and ensures strong logic-high drive (VOH ≥ 0.8×VCC) and low saturation voltage (VOL ≤ 0.3V), directly interfacing with standard µP reset inputs without level-shifting.

What is the minimum reset timeout period for the MAX6865UK33D1L+T, and how is it selected?

The MAX6865UK33D1L+T has a fixed minimum reset timeout period of 10ms, indicated by the "D1" suffix in the part number. This value is specified in Table 4 (Reset Timeout Periods) as D1 = 10ms (min), 15ms (typ), 25ms (max). Unlike MAX6861–MAX6863 variants, the MAX6865 does not feature a CT pin for dynamic timeout selection - D1 is hardwired internally.

Is the MAX6865UK33D1L+T compatible with 1.8V or 2.5V supply systems?

Yes, the MAX6865UK33D1L+T operates across VCC = 1.2V to 5.5V and maintains full functionality including reset assertion, watchdog timing, and MR response at 1.8V and 2.5V. Electrical Characteristics confirm ICC = 170nA typical at VCC = 1.8V and 190nA at VCC = 2.5V, with guaranteed reset validity down to VCC = +1.1V - making it fully compatible with modern low-voltage µP platforms.