Analog Devices Inc./Maxim Integrated MAX6865UK24D5S+T

Overview

The MAX6865UK24D5S+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 2.4V reset threshold (±2.5%), 300ms minimum reset timeout (D5), and integrated watchdog timer with 3.3s typical timeout (S suffix). It monitors VCC, responds to manual reset (MR) input, and asserts active-high push-pull RESET during brownout, power-up, or watchdog expiration - used in battery-powered medical and portable electronics.

For engineers reviewing the MAX6865UK24D5S+T datasheet, MAX6865UK24D5S+T pinout, MAX6865UK24D5S+T application, or MAX6865UK24D5S+T equivalent, this page delivers verified technical context, exact pin functions, real-world timing behavior, and validated alternative options for low-power µP reset and watchdog supervision.

Technical Context

The MAX6865UK24D5S+T implements a dual-monitoring architecture: a precision voltage detector with guaranteed reset validity down to VCC = +1.1V, and an independent watchdog timer that clears on any WDI edge (rising or falling) and expires if WDI remains static beyond 3.3s (typ). Its MR input features 10kΩ internal pullup and 1µs minimum pulse width support.

This device uses BiCMOS process technology (2848 transistors) and operates across –40°C to +85°C. The active-high push-pull RESET output drives to ≥0.8×VCC when deasserted (ISOURCE = 500µA, VCC ≥ 2.38V) and sinks to ≤0.3V when asserted (ISINK = 1.2mA, VCC ≥ 2.38V), ensuring reliable interface with modern µP reset inputs.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK24D5S+T, MAX6864UK24D5S+T removes MR but retains identical supervision timing and watchdog capability, while TPS3837K24DBVR trades nanopower operation and integrated watchdog for lower unit cost and TI's broad qualification pedigree - making it suitable for non-battery-critical industrial use cases.

Availability

MAX6865UK24D5S+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered IoT sensors, wearable health trackers, and low-power industrial controllers requiring stable component supply and long-term lifecycle support.

Supply support for MAX6865UK24D5S+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 interface applications in demanding environments.

The MAX6854–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in space-constrained, battery-operated systems - prioritizing nanoscale current draw, guaranteed low-VCC operation, and integrated watchdog reliability.

FAQ

What is the exact reset threshold voltage of the MAX6865UK24D5S+T?

The MAX6865UK24D5S+T has a factory-trimmed reset threshold voltage of 2.4V with ±2.5% tolerance over –40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "24" corresponds to VTH = 2.4V nominal. The MAX6865UK24D5S+T maintains this specification across its full operating temperature range and supply voltage (1.2V–5.5V).

Does the MAX6865UK24D5S+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK24D5S+T includes a watchdog timer with a typical timeout of 3.3s, indicated by the "S" suffix in the part number. The watchdog clears on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond this period. This behavior is documented in Table 3 (Watchdog Timeout) and applies specifically to the MAX6865UK24D5S+T variant.

What type of RESET output does the MAX6865UK24D5S+T provide?

The MAX6865UK24D5S+T provides an active-high push-pull RESET output (Pin 1), as confirmed in the MAX6865-specific pin description on page 8 of the datasheet. This eliminates the need for an external pullup resistor and ensures robust logic-level drive across its 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 MAX6865UK24D5S+T, and how is it selected?

The MAX6865UK24D5S+T has a fixed reset timeout period of 300ms minimum (D5 option), as encoded by the "D5" segment in its part number. This value is one of six factory-set options (D1–D6) and is not user-configurable. The D5 timeout is verified in Table 4 (Reset Timeout Periods) and ensures sufficient hold time for µP initialization sequences in low-power embedded systems using the MAX6865UK24D5S+T.

Is the MAX6865UK24D5S+T pin-compatible with other devices in the MAX68xx family?

The MAX6865UK24D5S+T uses the standard 5-pin SOT23-5 package and shares identical pinout with MAX6864/MAX6866 variants (Pin 1: RESET, Pin 2: GND, Pin 3: MR, Pin 4: WDI, Pin 5: VCC). However, it is not pin-compatible with MAX6861–MAX6863 (which use CT instead of WDI) or MAX6854–MAX6856 (which lack WDI). Pin compatibility is limited to the MAX6864/MAX6865/MAX6866 subgroup.