Analog Devices Inc./Maxim Integrated MAX6326UR31

Overview

MAX6326UR31 from Maxim Integrated is a precision ultra-low-power microprocessor supervisory circuit in SOT23-3 package, designed to monitor 3.08V supply rails and assert an active-low push-pull reset signal for ≥100ms after VCC rises above threshold. It operates from 1.2V to 5.5V, draws ≤1µA supply current, and maintains valid reset state down to 1V - ideal for battery-powered embedded controllers requiring reliable brownout detection.

For engineers reviewing the MAX6326UR31 datasheet, MAX6326UR31 pinout, MAX6326UR31 application, or MAX6326UR31 equivalent, this page delivers verified electrical specifications, thermal stability data, reset timing behavior across temperature, transient immunity characteristics, and validated alternative options for 3.08V µP reset supervision.

Technical Context

The MAX6326UR31 implements a factory-trimmed bandgap-based voltage comparator with 1.5% initial accuracy at +25°C and ±2.5% over –40°C to +85°C, paired with a precision delay timer ensuring minimum 100ms reset timeout. Its reset assertion logic remains functional down to VCC = 1.2V, and it ignores transients <20µs at 100mV overdrive.

Designed for direct interface with microcontrollers lacking internal reset supervision, the device features push-pull output capable of sourcing 500µA at 0.8·VCC and sinking 1.6mA at ≤0.3V - eliminating need for external pull-up resistors while supporting bidirectional reset pins when used with open-drain variants like MAX6328UR31.

Key Specifications

Pinout & Package

MAX6326UR31 is housed in a 3-pin SOT23-3 package (outline U3-1), with 1.3mm × 2.9mm footprint and 0.95mm height - optimized for space-constrained PCB layouts in handheld and sensor modules.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326UR31, the MAX6326XR31-T offers identical supervision performance in a smaller SC70 package for space-constrained designs, while the MAX809TR31-T provides baseline 3.08V reset capability at lower cost but sacrifices deep-brownout operation and transient rejection - making MAX6326UR31 the optimal choice for industrial and medical applications requiring robustness below 1.5V and noise resilience.

Availability

MAX6326UR31 is available at Aetrix Electronics and suitable for industrial PLCs, portable medical sensors, smart meter communication units, and automated test equipment controllers requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6326UR31 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 industrial, automotive, communications, and computing markets - emphasizing reliability, low power, and integration.

The MAX6326 family delivers ultra-low-power, factory-trimmed µP reset supervision for battery-operated and mission-critical embedded systems - targeting applications where deterministic reset behavior under brownout and noise is non-negotiable.

FAQ

What is the exact reset threshold voltage of MAX6326UR31 and how does it vary with temperature?

The MAX6326UR31 has a nominal reset threshold of 3.08V at +25°C, with ±1.5% tolerance at room temperature and ±2.5% over the full –40°C to +85°C operating range. Its tempco is 40ppm/°C, resulting in ≤15mV total drift across temperature - verified per Electrical Characteristics Table in the official datasheet. This ensures predictable reset behavior in thermal cycling environments.

Does MAX6326UR31 require any external components to function as a reset supervisor?

No, MAX6326UR31 requires zero external components. Its integrated bandgap reference, precision comparator, delay timer, and push-pull output driver enable complete reset supervision functionality in a 3-pin SOT23 package. Unlike open-drain alternatives, its push-pull output eliminates the need for an external pull-up resistor - simplifying design and reducing BOM count.

Can MAX6326UR31 operate reliably during deep brownout conditions?

Yes, MAX6326UR31 is fully functional down to VCC = 1.2V and guarantees correct reset state down to 1.0V. Its internal circuitry remains active and asserts reset continuously until VCC rises above 3.08V and sustains ≥100ms timeout - critical for preventing firmware corruption in battery-powered systems experiencing gradual discharge.

What is the maximum transient duration that MAX6326UR31 can ignore on the VCC line?

MAX6326UR31 rejects negative-going VCC transients up to 20µs in duration when the overdrive (VTH – VCC) is 100mV, as confirmed in the Typical Operating Characteristics graph "Maximum Transient Duration vs. Reset Threshold Overdrive". This immunity prevents false resets caused by switching noise or coupling spikes in shared power domains.

Is MAX6326UR31 pin-compatible with legacy Maxim reset supervisors like MAX809?

MAX6326UR31 shares the same SOT23-3 pinout (GND, RESET, VCC) and push-pull active-low output as MAX809TR31-T, but is not a drop-in replacement due to differences in VCC operating range (1.2V vs. 1.5V min) and transient immunity specification. While PCB layout is identical, system-level validation is required to confirm behavior under deep brownout and noise conditions.