Analog Devices Inc./Maxim Integrated MAX6865UK16D2L+T

Overview

MAX6865UK16D2L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, providing voltage monitoring (1.575V reset threshold), manual reset input (MR), watchdog timer (209s typical timeout), and push-pull active-high RESET output. It asserts reset during VCC brownout, MR assertion, or watchdog timeout, with guaranteed reset validity down to VCC = +1.1V. Used in battery-powered glucose monitors and portable medical devices requiring ultra-low quiescent current.

For engineers reviewing the MAX6865UK16D2L+T datasheet, MAX6865UK16D2L+T pinout, MAX6865UK16D2L+T application, or MAX6865UK16D2L+T equivalent, key selection criteria include its 170nA typical supply current, factory-trimmed 1.575V reset threshold, 40ms minimum reset timeout, 209s watchdog period, and SOT23-5 footprint compatibility with TPS3837.

Technical Context

The MAX6865UK16D2L+T integrates a precision voltage monitor with ±2.5% threshold accuracy, a watchdog timer that clears on any WDI edge (rising or falling), and a manual reset input with 250ns propagation delay. Its internal 10kΩ MR pullup eliminates external components.

Reset assertion occurs when VCC falls below 1.575V, MR is pulled low, or WDI remains static beyond 209s (typ). After recovery, reset remains asserted for ≥40ms before deassertion, ensuring reliable µP initialization. The push-pull active-high RESET output sources up to 500µA at VCC ≥ 2.38V.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, 2.9mm × 1.6mm footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3837K33DBVR and MAX6361KA29D3+T, the MAX6865UK16D2L+T uniquely combines ultra-low 170nA current, programmable watchdog (209s), and 1.575V precision threshold in a pin-compatible SOT23-5 - making it the sole option for long-life, safety-critical portable medical devices requiring both brownout and firmware supervision.

Availability

MAX6865UK16D2L+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered patient monitors, and wireless health sensors requiring stable component supply across multi-year production cycles.

Supply support for MAX6865UK16D2L+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, mixed-signal, and power management ICs for demanding industrial, medical, and communications applications.

The MAX68xx family delivers nanopower supervisory circuits optimized for battery-constrained portable medical electronics, featuring factory-trimmed thresholds, integrated watchdog timers, and guaranteed operation down to 1.1V VCC.

FAQ

What is the exact reset threshold voltage of the MAX6865UK16D2L+T?

The MAX6865UK16D2L+T has a factory-trimmed reset threshold of +1.575V, 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 "16" corresponds to 1.575V. The threshold remains stable across voltage and temperature, with normalized variation <±0.5% from –40°C to +85°C per Figure MAX6854 toc06.

Does the MAX6865UK16D2L+T require external components for basic operation?

No, the MAX6865UK16D2L+T operates autonomously with zero external components. It integrates a 10kΩ internal pullup on MR, precision voltage reference, reset timeout generator, and watchdog timer. Only a 0.1µF ceramic bypass capacitor on VCC to GND is recommended for noise immunity - not strictly required but strongly advised per Typical Operating Circuit and Applications Information sections.

What does the "L" suffix in MAX6865UK16D2L+T indicate?

The "L" suffix specifies the watchdog timeout period: 95s (min), 209s (typ), 487s (max). This is defined in Table 3 (Watchdog Timeout) and confirmed in the Ordering Information section, where "L" is inserted after the reset timeout code "D2" for MAX6864–MAX6869 variants. The "L" option provides long-interval supervision ideal for infrequently active firmware.

How does the MAX6865UK16D2L+T's watchdog timer respond to software hangs?

The MAX6865UK16D2L+T watchdog timer expires only if WDI remains static (high or low) beyond 209s (typ). It clears on *any* edge - rising or falling - so proper firmware design toggles WDI at multiple program points. This prevents stuck-loop evasion: if code hangs mid-subroutine without toggling WDI, the timer expires and asserts RESET for 40ms, forcing full system recovery.

Is the MAX6865UK16D2L+T pin-compatible with other MAX68xx supervisory ICs?

Yes, the MAX6865UK16D2L+T uses the standard 5-pin SOT23-5 pinout shared across the MAX6864–MAX6869 series (Pin 1: RESET, Pin 2: GND, Pin 3: MR, Pin 4: WDI, Pin 5: VCC), as shown in the Pin Configurations diagram on page 16. This allows drop-in replacement within the same functional group, though reset threshold, timeout, and output polarity vary by suffix.