Analog Devices Inc./Maxim Integrated MAX6326UR26

Overview

MAX6326UR26 from Maxim Integrated is a microprocessor supervisory circuit with windowed (min/max) watchdog timer, manual reset input, and precision voltage monitoring. It asserts an open-drain RESET output when VCC drops below 2.55V (±2.5%), guarantees valid reset down to VCC = +1.2V, and provides a 1ms pulsed WDPO fault signal for fast/slow watchdog timeouts. Used in automotive engine control units to detect firmware hangs during cold-cranking conditions.

For engineers reviewing the MAX6326UR26 datasheet, MAX6326UR26 pinout, MAX6326UR26 application, or MAX6326UR26 equivalent, this page delivers verified electrical parameters, SOT23-6 package mapping, watchdog timing options (A–H), reset threshold accuracy (±2.5%), and design-meaningful alternatives for safety-critical embedded systems.

Technical Context

The MAX6326UR26 implements a dual-threshold watchdog architecture that detects both early (faster than tWD1) and late (slower than tWD2) WDI falling edges - enabling detection of stuck loops and clock faults. Its internal comparator ensures ±2.5% reset threshold accuracy over −40°C to +125°C, with guaranteed operation down to VCC = +1.2V.

It features debounced MR input with ≥1µs minimum pulse width, 100ms minimum reset timeout after VCC recovery, and open-drain WDPO output pulsed low for 1ms upon fault detection. The device uses BiCMOS process (1371 transistors) and draws only 23µA typical supply current at 3.3V.

Key Specifications

Pinout & Package

MAX6326UR26 is housed in a 6-pin SOT23 package (outline U6-1, land pattern 90-0175), RoHS-compliant, with 0.95mm pitch and 2.9mm × 1.6mm footprint. Thermal resistance θ_JA = 115°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326UR26, MAX6326UR29 offers higher reset voltage for improved noise margin on 3.3V supplies, while TLV803EB26DBZR sacrifices watchdog intelligence for lower cost and smaller size - neither provides identical windowed fault detection or guaranteed 1.2V reset validity.

Availability

MAX6326UR26 is available at Aetrix Electronics and suitable for automotive engine control, industrial PLC I/O modules, medical infusion pump controllers, and railway signaling interfaces requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6326UR26 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 demanding industrial, automotive, and medical applications, with emphasis on reliability, low power, and high integration.

The MAX6323/MAX6324 family was engineered specifically for functional safety-critical embedded systems requiring deterministic reset behavior and robust watchdog supervision - especially where software execution timing must be validated across voltage and temperature extremes.

FAQ

What is the exact reset threshold voltage of MAX6326UR26?

The MAX6326UR26 has a nominal reset threshold of 2.55V, with ±2.5% accuracy over −40°C to +125°C. This corresponds to the UT26 variant in the MAX6323/MAX6324 family, confirmed in the Reset Threshold Range table (page 11 of datasheet). The actual threshold is laser-trimmed at wafer test and guaranteed between 2.48V and 2.63V under all operating conditions.

Does MAX6326UR26 support windowed watchdog functionality?

Yes, MAX6326UR26 implements true min/max (windowed) watchdog detection. It triggers WDPO on both fast faults (WDI falling edges closer than tWD1 = 15ms) and slow faults (no WDI edge longer than tWD2 = 15ms), as defined for suffix A in the Watchdog Timeout table. This dual-window architecture distinguishes it from basic timeout-only supervisors.

What package type and pin count does MAX6326UR26 use?

MAX6326UR26 uses a 6-pin SOT23 package (package code U6-1, outline 21-0058). Pin configuration is standardized across the MAX6323/MAX6324 family: Pin 1 = MR, Pin 2 = GND, Pin 3 = WDI, Pin 4 = VCC, Pin 5 = WDPO, Pin 6 = RESET - all verified in the Pin Configuration diagram (page 2) and Pin Description table (page 5).

Is MAX6326UR26 qualified for automotive applications?

MAX6326UR26 is not explicitly marked with /V suffix (which denotes AEC-Q100 qualification), so it is rated for extended industrial temperature range (−40°C to +125°C) but not formally automotive-qualified. For automotive use, select MAX6326UR26/V-T or MAX6326UR26/V+T variants, which include additional stress testing and PPAP documentation per AEC-Q100 Rev H.

What is the minimum supply voltage at which MAX6326UR26 guarantees valid RESET output?

MAX6326UR26 guarantees valid RESET output down to VCC = +1.2V, as stated in the General Description and Electrical Characteristics table (page 2). Below this voltage, the RESET driver ceases sinking current and becomes high-impedance - a design feature enabling predictable fail-safe behavior during deep brownout conditions.