Analog Devices Inc./Maxim Integrated MAX6865UK36D1L+T

Overview

The MAX6865UK36D1L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 3.6V reset threshold (±2.5%), 10ms minimum reset timeout, and integrated watchdog timer with 209s typical timeout. It monitors VCC, accepts manual reset (MR), and asserts active-low push-pull RESET during brownout, power-up, or watchdog expiration - used in battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK36D1L+T datasheet, MAX6865UK36D1L+T pinout, MAX6865UK36D1L+T application, or MAX6865UK36D1L+T equivalent, key selection criteria include guaranteed RESET validity down to VCC = +1.1V, immunity to sub-40µs VCC transients, MR glitch rejection of 200ns, and compatibility with 1.2V–5.5V supply rails in space-constrained portable systems.

Technical Context

This device integrates three core functions: precision voltage monitoring with hysteresis (0.5% of VTH), a manual reset input with internal 10kΩ pullup and 1µs minimum pulse width, and a watchdog timer that clears on any WDI edge and expires if WDI remains static beyond 209s (typ). The reset assertion persists for ≥10ms after VCC exceeds VTH and MR deasserts.

It operates across –40°C to +85°C, supports push-pull active-low RESET output referenced to VCC, and guarantees functional reset behavior even as VCC falls to +1.1V - critical for low-voltage battery discharge scenarios where µP operation must remain deterministic until full shutdown.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount. Compact 2.9mm × 1.6mm footprint with 0.95mm height - optimized for space-constrained portable PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3836K33DBVR and MAX6361KA29D3+T, the MAX6865UK36D1L+T uniquely delivers 3.6V supervision, 209s watchdog, and 170nA ICC in one SOT23-5 package - making it the only option for long-life, safety-critical portable medical devices requiring both precise brownout detection and autonomous firmware health monitoring.

Availability

MAX6865UK36D1L+T is available at Aetrix Electronics and suitable for glucose monitors, portable ECG devices, and smart inhalers requiring stable component supply with full lifecycle traceability and RoHS-compliant lead-free packaging.

Supply support for MAX6865UK36D1L+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 was engineered specifically for ultra-low-power microprocessor supervision in battery-constrained portable medical and handheld electronics - prioritizing nanoscale ICC, wide VCC range, and integrated watchdog reliability.

FAQ

What is the exact reset threshold voltage of the MAX6865UK36D1L+T?

The MAX6865UK36D1L+T has a factory-trimmed reset threshold of +3.600V with ±2.5% tolerance over temperature (–40°C to +85°C), corresponding to the "36" suffix in its part number per Maxim's Threshold Suffix Guide. This value is guaranteed across the full operating range and does not require external calibration.

Does the MAX6865UK36D1L+T support active-high reset output?

No, the MAX6865UK36D1L+T provides only an active-low push-pull RESET output (Pin 1). The "65" in the part number identifies it as a member of the MAX6864–MAX6866 series with active-low RESET; active-high variants like MAX6865UK36D1L+T do not exist - MAX6865 is defined exclusively as active-low in the Selector Guide and Pin Description tables.

How does the watchdog timer in the MAX6865UK36D1L+T clear and expire?

The MAX6865UK36D1L+T watchdog timer clears on every rising or falling edge at the WDI input (Pin 4) and expires only if WDI remains static (high or low) for longer than 209s (typical, L-suffix). It does not run while RESET is asserted, and resumes counting immediately upon RESET deassertion - ensuring deterministic response to firmware hangs without false triggers from noise.

Can the MAX6865UK36D1L+T operate reliably below 1.2V?

No - the MAX6865UK36D1L+T specifies a minimum operating VCC of 1.2V per Absolute Maximum Ratings and Electrical Characteristics tables. While RESET remains valid down to VCC = +1.1V, the device is not guaranteed to function correctly (e.g., monitor, time, or assert reset) below 1.2V, and supply current and timing parameters are not characterized in that region.

What is the purpose of the "D1L" suffix in MAX6865UK36D1L+T?

In MAX6865UK36D1L+T, "D1" selects the 10ms minimum reset timeout period (per Table 4), and "L" selects the 209s typical watchdog timeout (per Table 3). These suffixes are mandatory for MAX6864–MAX6869 parts and define core timing behavior - D1L is not interchangeable with D3S or other combinations without altering reset hold time and watchdog sensitivity.