Analog Devices Inc./Maxim Integrated MAX6328UR22

Overview

MAX6328UR22 from Maxim Integrated is an ultra-low-power open-drain microprocessor supervisory circuit designed to monitor 2.2V power supplies and assert an active-low reset signal during brownout, power-up, and power-down events. It features a factory-trimmed 2.2V reset threshold (±1.5% at +25°C), 100ms minimum reset timeout, 1µA max supply current, and operation down to 1V VCC - making it suitable for battery-powered portable systems requiring reliable power-on reset functionality.

For engineers reviewing the MAX6328UR22 datasheet, MAX6328UR22 pinout, MAX6328UR22 application, or MAX6328UR22 equivalent, this device serves as a precision, low-quiescent-current reset supervisor for 2.2V logic rails in space-constrained embedded systems where transient immunity, minimal external components, and guaranteed reset assertion below 1V are critical selection criteria.

Technical Context

The MAX6328UR22 implements a precision bandgap-based voltage comparator with hysteresis (9.5mV typical) to detect VCC falling below its 2.2V threshold, triggering an open-drain RESET output that remains asserted for ≥100ms after VCC recovers above threshold. Its internal design eliminates need for external RC timing components while maintaining full specification across –40°C to +85°C.

It features transient immunity against fast negative-going VCC glitches (e.g., up to 200µs at 100mV overdrive), operates with no external components, and guarantees correct reset state down to 1V VCC - enabling robust supervision even during deep brownout conditions before system shutdown.

Key Specifications

Pinout & Package

MAX6328UR22 is housed in a 3-pin SOT23-3 package (JEDEC MO-178AA), with 1.3mm × 2.9mm footprint and 1.45mm height - optimized for high-density PCB layouts in portable electronics.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6328UR22, MAX809TR22D3T offers push-pull drive but lacks open-drain flexibility, while TPS3808G01QDBVRQ1 provides automotive qualification and adjustability at higher quiescent current - making MAX6328UR22 optimal for cost-sensitive, space-constrained portable designs needing precise 2.2V supervision and multi-device reset arbitration.

Availability

MAX6328UR22 is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, automotive body control units, and battery management systems requiring stable component supply with guaranteed long-term sourcing.

Supply support for MAX6328UR22 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, computing, and consumer applications.

The MAX6328UR22 belongs to Maxim's µP supervisory circuit product line, engineered specifically for ultra-low-power, precision reset generation in battery-operated and space-constrained embedded systems where reliability under brownout and transient conditions is essential.

FAQ

What is the exact reset threshold voltage of MAX6328UR22 and how tightly is it specified?

The MAX6328UR22 has a factory-trimmed reset threshold of 2.2V, with a tolerance of ±1.5% at +25°C and ±2.5% over the full –40°C to +85°C temperature range. This precision is achieved via on-die trimming during wafer test, eliminating the need for external calibration. The MAX6328UR22 datasheet confirms this value in Table 1 and Electrical Characteristics section under "Reset Threshold" (VTH).

Does MAX6328UR22 require any external components to function as a reset supervisor?

No, the MAX6328UR22 requires zero external components to perform its core reset supervision function. Its internal voltage reference, comparator, and timing circuitry are fully integrated. Only an external pull-up resistor on the open-drain RESET pin is needed to establish a logic-high level - a standard requirement for all open-drain outputs and not considered a functional external component for reset generation.

What is the minimum VCC voltage at which MAX6328UR22 guarantees correct reset behavior?

The MAX6328UR22 guarantees correct reset assertion and release behavior down to VCC = 1.0V, as explicitly stated in the General Description and Absolute Maximum Ratings sections. This allows the MAX6328UR22 to remain functional and hold the system in reset even during severe brownout conditions well below its 2.2V threshold - a key differentiator for fail-safe operation in battery-powered systems.

How does the open-drain output of MAX6328UR22 benefit system-level reset architecture?

The open-drain RESET output of MAX6328UR22 enables wired-OR connection with other reset sources (e.g., watchdog timers, manual reset buttons, or other supervisors), allowing any device to force system reset. It also permits level-shifting via pull-up to higher or lower I/O voltages - critical for interfacing with µPs having bidirectional reset pins like the Motorola 68HC11, as documented in the Applications Information section of the MAX6328UR22 datasheet.

Is MAX6328UR22 pin-compatible with other members of the MAX6326–MAX6348 family?

Yes, all members of the MAX6326/MAX6327/MAX6328/MAX6346/MAX6347/MAX6348 family share identical 3-pin SOT23-3 and SC70-3 packages and pinouts (VCC, RESET, GND). The MAX6328UR22 is therefore pin-compatible with MAX6326UR22 (push-pull) and MAX6327UR22 (active-high push-pull), differing only in output type and logic polarity - enabling flexible design reuse with minimal layout changes.