Analog Devices Inc./Maxim Integrated MAX6321HPUK26CY+

Overview

MAX6321HPUK26CY+ from Maxim Integrated is a 5-pin SOT23 microprocessor supervisory circuit with active-low open-drain reset output, 2.63V factory-trimmed reset threshold (±2.5% over -40°C to +125°C), 140ms minimum reset timeout, and 1.6s typical watchdog timeout. It monitors VCC supply integrity and provides system-level reset assertion during power-up, brownout, or software lockup in embedded controllers.

For engineers reviewing the MAX6321HPUK26CY+ datasheet, MAX6321HPUK26CY+ pinout, MAX6321HPUK26CY+ application, or MAX6321HPUK26CY+ equivalent, key selection criteria include its open-drain RESET output compatible with mixed-voltage systems up to 6V, guaranteed reset validity down to VCC = 1V, immunity to sub-4µs negative VCC transients, and AEC-Q100 qualification for automotive-grade reliability.

Technical Context

The MAX6321HPUK26CY+ integrates a precision voltage detector with 40ppm/°C temperature coefficient, a programmable watchdog timer cleared by WDI edge transitions (≥50ns pulse width), and manual reset input with 100ns glitch rejection. Its internal 52kΩ MR pullup enables direct connection of a momentary switch to ground without external components.

As an open-drain device, it requires an external pullup resistor on RESET (typically 10kΩ) to any supply up to 6V - enabling level-shifting across domains. The watchdog timeout is factory-set to 1.6s (Y-T variant), and reset timeout is fixed at 140ms (C-T variant), both guaranteed over full industrial temperature range (-40°C to +125°C).

Key Specifications

Pinout & Package

MAX6321HPUK26CY+ is housed in a RoHS-compliant 5-pin SOT23 package (package code U5+2A, outline 21-0057), measuring 2.9mm × 1.6mm × 1.1mm, with exposed pad for thermal enhancement and standard JEDEC land pattern 90-0174.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6321HPUK26CY+, MAX6321HPUK29CY+ offers identical functionality with higher reset threshold for 3V systems, while TLV803EC26DBVR reduces size and current but sacrifices watchdog, manual reset, and open-drain versatility - making it suitable only for simple reset-only use cases.

Availability

MAX6321HPUK26CY+ is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLC I/O subsystems, and battery-powered telematics units requiring stable component supply with AEC-Q100 compliance and long-term lifecycle support.

Supply support for MAX6321HPUK26CY+ 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 communications applications, with emphasis on reliability, integration, and low-power operation.

The MAX6316–MAX6322 family delivers highly integrated μP supervisory functions - combining reset monitoring, watchdog supervision, and manual reset in miniature SOT23 packages for space-constrained embedded systems.

FAQ

What is the exact reset threshold voltage of MAX6321HPUK26CY+ and how does it vary with temperature?

The MAX6321HPUK26CY+ has a factory-trimmed nominal reset threshold of 2.63V at +25°C, with tolerance of ±1.5% at room temperature and ±2.5% over the full operating range (–40°C to +125°C). Its temperature coefficient is 40ppm/°C, meaning threshold drift is limited to ±0.13V across the entire temperature span - ensuring predictable brownout detection in automotive and industrial environments where MAX6321HPUK26CY+ is deployed.

Does MAX6321HPUK26CY+ require an external pullup resistor on the RESET pin, and what value is recommended?

Yes, MAX6321HPUK26CY+ features an active-low open-drain RESET output and requires an external pullup resistor. A 10kΩ resistor to any supply up to 6V is recommended for most applications - it ensures valid logic-high levels while limiting sink current to <320µA when RESET is asserted. The value must be selected to meet the driven logic's VIH requirement and account for total bus capacitance and leakage paths connected to the RESET line in the system using MAX6321HPUK26CY+.

Can the watchdog function of MAX6321HPUK26CY+ be disabled, and if so, how?

Yes, the watchdog function of MAX6321HPUK26CY+ can be disabled by leaving the WDI pin unconnected or by three-stating the driver connected to it. When WDI is open-circuited, the internal watchdog timer is automatically serviced at intervals equal to 7/8 of the nominal timeout period (1.4s for MAX6321HPUK26CY+), preventing unintended resets. This allows MAX6321HPUK26CY+ to operate as a pure power-monitoring supervisor without software intervention.

What is the minimum VCC voltage at which MAX6321HPUK26CY+ guarantees valid reset output states?

MAX6321HPUK26CY+ guarantees valid reset output states - specifically, RESET remains a defined logic low when asserted - down to VCC = 1.0V. Below this voltage, the internal circuitry may no longer drive the open-drain output reliably. For applications requiring reset signaling down to 0V, external pulldown resistors are not applicable to MAX6321HPUK26CY+ due to its open-drain architecture; instead, system-level power sequencing must ensure VCC stays above 1.0V during critical reset assertion.

Is MAX6321HPUK26CY+ qualified for automotive applications, and what standards does it meet?

Yes, MAX6321HPUK26CY+ is AEC-Q100 qualified (Grade 1: –40°C to +125°C ambient), with full reliability testing including HTOL, TCT, and ESD (HBM ±2kV, CDM ±1kV). It meets automotive requirements for reset supervision in body electronics, infotainment, and ADAS subsystems. The "+" suffix denotes lead-free packaging compliant with RoHS Directive 2011/65/EU, and the device is manufactured in certified automotive-grade facilities - confirming MAX6321HPUK26CY+ suitability for production automotive designs.