Analog Devices Inc./Maxim Integrated MAX6323BUT31-T

Overview

MAX6323BUT31-T from Maxim Integrated is a push-pull output microprocessor supervisory circuit with windowed (min/max) watchdog timer, 3.08V ±2.5% reset threshold, and 100ms minimum reset timeout delay. It monitors +3.3V power supplies in automotive engine control units and industrial PLCs, asserting active-low RESET when VCC drops below threshold or MR is pulled low.

For engineers reviewing the MAX6323BUT31-T datasheet, MAX6323BUT31-T pinout, MAX6323BUT31-T application, or MAX6323BUT31-T equivalent, key selection criteria include its factory-trimmed 3.08V reset threshold, B-suffix 15ms fast/100ms slow watchdog timeout window, guaranteed RESET validity down to VCC = +1.2V, and SOT23-6 package compatibility with space-constrained embedded designs.

Technical Context

The MAX6323BUT31-T implements a dual-window watchdog architecture: fast timeout (tWD1 = 10–15ms) detects premature WDI pulses, while slow timeout (tWD2 = 100–150ms) identifies missed pulses. Its internal reset comparator guarantees operation across -40°C to +125°C with ±2.5% voltage threshold accuracy over temperature.

RESET is push-pull active-low with VOH ≥ 0.8×VCC at 500μA and VOL ≤ 0.4V at 1.2mA; WDPO is open-drain, pulsing low for 1ms on fault detection. The device draws only 23μA typical supply current and features debounced MR input with 1μs minimum pulse width and 100ns glitch immunity.

Key Specifications

Pinout & Package

MAX6323BUT31-T is housed in a 6-pin SOT23 package (package code U6+1), with 1.6mm × 2.9mm footprint and 1.1mm height, suitable for high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6323BUT31-T, MAX6324BUT31-T offers identical supervision capability but requires an external pullup on RESET, while TLV809K33DBZR omits watchdog entirely-making MAX6323BUT31-T the sole option for applications demanding both precise 3.08V reset and min/max timing fault detection.

Availability

MAX6323BUT31-T is available at Aetrix Electronics and suitable for automotive engine control units, industrial programmable logic controllers, and medical infusion pumps requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6323BUT31-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 automotive, industrial, and communications applications.

The MAX6323/MAX6324 product line delivers highly accurate, temperature-stable supervisory functions specifically for safety-critical embedded systems requiring guaranteed reset behavior and robust watchdog supervision.

FAQ

What is the exact reset threshold voltage of MAX6323BUT31-T and how is it trimmed?

The MAX6323BUT31-T has a factory-laser-trimmed reset threshold of 3.08V with ±2.5% accuracy over -40°C to +125°C. This value is fixed per unit and corresponds to the "31" suffix in the part number, referencing the 3.00V–3.15V nominal range in the Reset Threshold Range table. No external adjustment is possible-the precision is achieved during wafer-level trimming.

Does MAX6323BUT31-T support windowed watchdog functionality, and what are its timeout values?

Yes, MAX6323BUT31-T implements true min/max (windowed) watchdog supervision. The "B" suffix specifies a fast timeout of 10–15ms and a slow timeout of 100–150ms. These windows detect both abnormally rapid and excessively delayed WDI pulses-enabling reliable identification of software execution anomalies beyond simple timeout detection.

Can MAX6323BUT31-T operate reliably at VCC = +1.2V, and what happens to RESET output below that?

Yes, MAX6323BUT31-T guarantees valid RESET output down to VCC = +1.2V. Below +1.2V, the RESET output becomes high-impedance (open-circuit) and ceases to sink current. This behavior is intentional-ensuring predictable failure mode during deep brownout while avoiding false logic states on the reset line in systems where µP is already nonfunctional.

What is the function of the WDPO pin on MAX6323BUT31-T, and how should it be interfaced?

The WDPO pin on MAX6323BUT31-T is an open-drain watchdog pulse output that asserts low for 1ms upon detection of either fast or slow watchdog faults. It must be pulled up externally to a voltage ≤+6V. WDPO remains inactive while RESET is asserted, and its pulse provides a dedicated fault signal-enabling NMI triggering or separate fault logging without affecting the primary reset path.

How does the manual reset (MR) input behave on MAX6323BUT31-T, and is external debouncing required?

The MR input on MAX6323BUT31-T is internally pulled up to VCC and debounced-requiring no external RC network. It responds to a minimum 1μs low pulse and rejects transients as short as 100ns. When asserted, MR forces RESET low, clears the watchdog timer, and holds RESET active for ≥100ms after MR returns high-providing clean, noise-immune manual reset capability.