Analog Devices Inc./Maxim Integrated MAX822MUS

Overview

MAX822MUS from Maxim Integrated is an active-high microprocessor supervisory circuit in a 4-pin SOT143 package, designed to monitor +3V to +5V power supplies and assert reset during brownout, power-up, or power-down events. It features pin-selectable reset timeout delays (1ms max, 20ms min, or 100ms min), 2.5µA supply current, guaranteed operation from −40°C to +125°C, and a nominal reset threshold of 4.38V - ideal for portable equipment and critical µP power monitoring.

For engineers reviewing the MAX822MUS datasheet, MAX822MUS pinout, MAX822MUS application, or MAX822MUS equivalent, key selection criteria include its active-high RESET output, SRT-configurable timeout, low quiescent current, wide temperature range, and compatibility with 3V/5V systems requiring reliable power-on sequencing and transient immunity.

Technical Context

The MAX822MUS implements a precision voltage comparator with hysteresis-free threshold detection and an internal timer controlled by the SRT pin. Its reset assertion logic remains valid while VCC ≥ 1.2V, and the RESET output stays high for the full timeout period after VCC rises above the threshold.

It uses a dedicated SRT input to select one of three discrete timeout modes without external components: GND → 1ms (max), VCC → 20ms (min), or open → 100ms (min). The device ignores fast VCC transients (<12µs at 100mV overdrive) and maintains reset accuracy with ±30ppm/°C tempco across −40°C to +125°C.

Key Specifications

Pinout & Package

SOT143-4 surface-mount package (3.0mm × 1.5mm × 1.0mm), lead-free option available (MAX822MUS+T), JEDEC-compliant footprint per drawing 21-0052.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage supervisor applications.

Compared with TLV803EB29DBZR and ADM6315-43ARTZ-RL, the MAX822MUS uniquely offers pin-selectable timeout, active-high output, and 4.38V threshold in a 4-pin SOT143 - enabling precise timing control and direct µP compatibility without external logic or resistor networks.

Availability

MAX822MUS is available at Aetrix Electronics and suitable for portable medical devices, industrial PLC modules, automotive body control units, and bar-code scanners requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX822MUS 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, and computing markets.

The MAX822MUS belongs to Maxim's µP supervisory product line, engineered specifically for robust, low-power voltage monitoring and reset generation in space-constrained, thermally demanding embedded systems.

FAQ

What is the reset threshold voltage of the MAX822MUS?

The MAX822MUS has a nominal reset threshold voltage of 4.38V, with guaranteed minimum and maximum values of 4.31V and 4.45V respectively over the full −40°C to +125°C temperature range. This threshold is factory-trimmed and specified in the Electrical Characteristics table of the MAX822 datasheet (Rev 3, 19-1122). The MAX822MUS uses this precise threshold to detect undervoltage conditions on the VCC rail and initiate the reset sequence.

How do I configure the reset timeout delay on the MAX822MUS?

The reset timeout delay of the MAX822MUS is configured using the SRT pin: connect SRT to GND for a 1ms (maximum) delay, connect SRT to VCC for a 20ms (minimum) delay, or leave SRT unconnected for a 100ms (minimum) delay. Capacitive loading on SRT must remain below 200pF to ensure reliable 100ms operation. This hardware-based selection eliminates firmware dependencies and ensures deterministic timing independent of µP state.

Is the MAX822MUS compatible with 3V systems?

The MAX822MUS supports VCC from 1.2V to 5.5V and is specified for precision monitoring of +3V to +5V supplies. However, its 4.38V nominal threshold makes it primarily intended for +5V systems. For +3V applications, Maxim offers other variants in the same family - such as MAX822TUS (3.08V threshold) or MAX822SUS (2.93V threshold) - which are better matched to 3V rail supervision. Using MAX822MUS on a 3V rail would not assert reset, as 3V remains below its threshold.

Does the MAX822MUS provide reset assertion during power-down?

Yes, the MAX822MUS asserts its active-high RESET output whenever VCC falls below the 4.38V threshold - including during power-down, brownout, or battery depletion. RESET remains high for the full pin-selected timeout period after VCC recovers above the threshold. The device guarantees valid RESET output down to VCC = 1.2V, and includes transient immunity to reject short-duration VCC glitches that could cause false resets.

What package type and dimensions does the MAX822MUS use?

The MAX822MUS is housed in a 4-pin SOT143 (also designated SOT-143 or U4-1*) package measuring 3.0mm × 1.5mm × 1.0mm. Its pinout is standardized per JEDEC outline 21-0052, with pins arranged as GND (1), RESET (2), SRT (3), and VCC (4) in top-view orientation. Lead-free versions (e.g., MAX822MUS+T) are available and share identical mechanical dimensions and solder-reflow profiles.