Analog Devices Inc./Maxim Integrated MAX6326UR23

Overview

MAX6326UR23 from Maxim Integrated is an ultra-low-power, active-low push-pull microprocessor supervisory circuit designed to monitor 2.3V power supplies and assert a reset signal during brownout or power-up conditions. It features a factory-trimmed 2.32V reset threshold (±1.5% at +25°C), 100ms minimum reset timeout, 1µA maximum supply current at +25°C, and operation down to 1V VCC - making it suitable for battery-powered portable systems requiring reliable power-on reset functionality.

For engineers reviewing the MAX6326UR23 datasheet, MAX6326UR23 pinout, MAX6326UR23 application, or MAX6326UR23 equivalent, key selection criteria include its SOT23-3 open-drain–incompatible push-pull output, precise 2.32V threshold for 2.5V rail monitoring, guaranteed reset assertion below VCC = 1V, immunity to sub-200µs VCC transients, and compatibility with space-constrained embedded controllers.

Technical Context

The MAX6326UR23 implements a precision bandgap-based voltage comparator with internal hysteresis (9.5mV typical) to detect VCC falling below its 2.32V threshold. Its reset logic holds the active-low RESET output asserted for ≥100ms after VCC rises above threshold, ensuring stable µP initialization.

It operates across -40°C to +85°C with ±2.5% total threshold variation over temperature and 40ppm/°C tempco. The push-pull output drives low to ≤0.4V at 1.6mA sink and high to ≥0.8·VCC at 500µA source, eliminating external pull-up components in most µP interface configurations.

Key Specifications

Pinout & Package

SOT23-3 package: 1.3mm × 2.9mm × 1.0mm body, surface-mount, lead-free compatible (suffix +T), JEDEC MO-178AA compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809TRD23+T and TPS3808G12DBVR, the MAX6326UR23 delivers superior low-power performance (1µA vs. ≥1.8µA), guaranteed 1V operation for robust brownout response, and integrated push-pull drive that eliminates external passives - reducing design risk in portable and automotive applications.

Availability

MAX6326UR23 is available at Aetrix Electronics and suitable for portable medical devices, industrial PLCs, automotive body control units, and smart energy meters requiring stable component supply with long-term lifecycle support.

Supply support for MAX6326UR23 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 power, sensing, and interface applications in industrial, automotive, and computing markets.

The MAX6326 series belongs to Maxim's ultra-low-power µP supervisory product line, engineered specifically for battery-operated and energy-constrained systems needing reliable, single-chip reset generation with minimal footprint and leakage.

FAQ

What is the exact reset threshold voltage of MAX6326UR23 and how tightly is it specified?

The MAX6326UR23 has a factory-trimmed reset threshold of 2.32V, with ±1.5% tolerance at +25°C and ±2.5% over the full -40°C to +85°C operating range. This specification is confirmed in Table 1 of the official datasheet and ensures consistent brownout detection for 2.5V supply rails without external calibration. The MAX6326UR23 achieves this via laser trimming during wafer sort.

Does MAX6326UR23 support operation below 1.8V, and what is its minimum functional VCC?

Yes, the MAX6326UR23 is fully specified to operate down to 1.0V VCC, and its reset comparator remains functional and correctly asserts RESET even at this level. This capability is explicitly guaranteed in the Absolute Maximum Ratings and Electrical Characteristics tables, enabling reliable reset hold during deep brownout events where other supervisors fail. The MAX6326UR23 maintains this behavior across temperature.

Is MAX6326UR23 pin-compatible with legacy Maxim reset ICs like MAX809?

Yes, the MAX6326UR23 uses the same SOT23-3 pinout (GND, RESET, VCC) and is explicitly stated as pin-compatible with MAX803/MAX809/MAX810 in the datasheet's Features section. This allows direct replacement in existing layouts without PCB modification, provided the output type (active-low push-pull) and threshold match system requirements. The MAX6326UR23 retains identical mechanical and electrical interface behavior.

What is the maximum transient duration the MAX6326UR23 can ignore on the VCC line?

The MAX6326UR23 rejects VCC transients up to 200µs in duration when the overdrive (VTH – VCC) is 100mV, as shown in Figure MAX6326-04 of the datasheet. This immunity is achieved through internal filtering and comparator hysteresis (9.5mV typical), preventing false resets from switching noise or ESD-induced dips. The MAX6326UR23 maintains this rejection profile across its full temperature range.

How does the push-pull output of MAX6326UR23 simplify µP interface compared to open-drain alternatives?

The push-pull output of the MAX6326UR23 actively drives both high (≥0.8·VCC) and low (≤0.4V), eliminating the need for an external pull-up resistor required by open-drain reset ICs. This reduces BOM count, saves PCB space, removes timing uncertainty from RC time constants, and improves noise immunity on the reset line. The MAX6326UR23 thus enables cleaner, more deterministic reset signaling to µPs such as STM32L0 and Silicon Labs EFM32.