Analog Devices Inc./Maxim Integrated MAX6323FUT26

Overview

MAX6323FUT26 from Maxim Integrated is a microprocessor supervisory circuit with windowed (min/max) watchdog, manual reset, and precision V_CC monitoring. It asserts push-pull RESET when supply drops below 2.55V (±2.5%), guarantees valid reset down to V_CC = +1.2V, features 47ms/63ms slow/fast watchdog timeout windows, and draws only 23µA typical supply current. It is used in automotive engine control units to detect firmware lockup during cold-cranking conditions.

For engineers reviewing the MAX6323FUT26 datasheet, MAX6323FUT26 pinout, MAX6323FUT26 application, or MAX6323FUT26 equivalent, this page delivers verified electrical parameters, SOT23-6 terminal mapping, factory-trimmed watchdog timing behavior, and real-world design implications for brownout resilience and fault-triggered maintenance signaling.

Technical Context

The MAX6323FUT26 implements a dual-threshold watchdog timer that detects both fast faults (WDI falling edges closer than 17ms) and slow faults (no WDI edge longer than 47ms), with WDPO pulsed low for 1ms on detection. Its internal reset comparator operates across -40°C to +125°C with ±2.5% threshold accuracy and guaranteed functionality down to V_CC = +1.2V.

This variant uses laser-trimmed thresholds: nominal reset voltage = 2.63V (UT26 suffix), slow timeout = 47ms (F suffix), and fast timeout = 17ms. The push-pull RESET output drives high to 0.8×V_CC at 800µA source current and sinks to ≤0.4V at 100µA sink current, enabling direct interface with CMOS logic without external pullups.

Key Specifications

Pinout & Package

MAX6323FUT26 is housed in a 6-pin SOT23-6 package (JEDEC MO-178AA), with 1.6mm × 2.9mm footprint and 1.1mm max height. Pin 1 is marked by a dot; device orientation follows standard top-view labeling.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6323HUT26 and TPS3808G33DBVR, MAX6323FUT26 uniquely combines 2.63V precision reset, 47ms/17ms windowed watchdog timing, and push-pull output in one SOT23-6 device-enabling compact, self-contained supervision for time-deterministic embedded systems.

Availability

MAX6323FUT26 is available at Aetrix Electronics and suitable for automotive ECU designs, industrial PLC modules, medical infusion pump controllers, and railway signaling interface boards requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6323FUT26 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for demanding industrial, automotive, and medical applications.

The MAX6323 family was designed specifically for microprocessor supervision in harsh environments-delivering precision voltage monitoring, windowed watchdog timing, and guaranteed reset operation down to 1.2V to meet ASIL-B and IEC 61508 functional safety requirements.

FAQ

What is the exact reset threshold voltage of MAX6323FUT26 and how is it trimmed?

The MAX6323FUT26 has a factory-laser-trimmed reset threshold of 2.63V (nominal), with ±2.5% accuracy over -40°C to +125°C. This value is fixed per unit and corresponds to the "26" suffix in the part number, referencing the UT26 reset threshold option in the MAX6323 datasheet's Reset Threshold Range table. No external calibration is required.

Does MAX6323FUT26 support windowed watchdog functionality, and what are its timeout values?

Yes, MAX6323FUT26 implements true min/max (windowed) watchdog functionality. Its slow timeout is 47ms (typ) and fast timeout is 17ms (typ), corresponding to the "F" suffix in the part number. These values are factory-trimmed and specified in the Watchdog Timeout table of the MAX6323/MAX6324 datasheet under the FUT designation.

What is the output type of the RESET pin on MAX6323FUT26, and does it require an external pullup resistor?

The RESET output of MAX6323FUT26 is push-pull (not open-drain), as confirmed by the MAX6323 designation (vs. MAX6324). It actively drives high to 0.8×V_CC and low to ≤0.4V, so no external pullup resistor is required-unlike the MAX6324 open-drain variant. This simplifies PCB layout and reduces component count.

Can MAX6323FUT26 operate reliably at V_CC = +1.2V, and what happens to RESET output below that voltage?

Yes, MAX6323FUT26 guarantees valid RESET assertion down to V_CC = +1.2V, as stated in the General Description and Electrical Characteristics tables. Below +1.2V, the RESET output ceases to sink current and becomes high-impedance; however, most µPs are nonfunctional below this rail, making the guarantee sufficient for fail-safe shutdown sequencing.

How is the watchdog input (WDI) signal interpreted, and what is the minimum pulse width it accepts?

WDI is edge-sensitive: the internal watchdog timer resets on each falling edge. MAX6323FUT26 requires a minimum WDI pulse width of 300ns (at V_CC = 5.5V) and provides 100ns glitch immunity. Transitions outside the 17ms–47ms window trigger WDPO pulses-enabling detection of both stuck loops and missed deadlines in firmware execution.