Analog Devices Inc./Maxim Integrated MAX822SUS-T

Overview

MAX822SUS-T 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 a pin-selectable reset timeout of 1ms (max), 20ms (min), or 100ms (min), 2.93V reset threshold, 2.5µA supply current, and guaranteed operation from –40°C to +125°C - ideal for portable battery-powered instrumentation and embedded controllers.

For engineers reviewing the MAX822SUS-T datasheet, MAX822SUS-T pinout, MAX822SUS-T application, or MAX822SUS-T equivalent, key selection considerations include its active-high RESET output, SRT-configurable timeout, precise 2.93V threshold with ±1.5% accuracy over temperature, transient immunity up to 12µs at 100mV overdrive, and compatibility with low-voltage µP systems requiring valid reset down to VCC = 1.2V.

Technical Context

The MAX822SUS-T implements a precision voltage comparator with hysteresis-free threshold detection and an internal monostable timer triggered on VCC rise above 2.93V. Its SRT input directly selects one of three discrete timeout modes via GND/VCC/unconnected states - no external timing components required.

Reset assertion is immune to fast VCC transients (e.g., ≤12µs negative glitches at 100mV overdrive) and maintains output validity across full industrial temperature range (–40°C to +125°C), with RESET output voltage specified as VOH ≥ 0.8VCC at ISOURCE = 150µA and VOL ≤ 0.4V at ISINK = 1.2mA.

Key Specifications

Pinout & Package

SOT143-4 surface-mount package (3.0mm × 1.5mm × 1.0mm height), lead-free compatible, with exposed pad not electrically connected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX822TUS-T, the MAX822SUS-T offers earlier reset assertion for systems with wider 3V supply tolerances; versus TPS3808G12DBVR, it delivers plug-and-play timing configuration without resistors or layout overhead - critical for space-constrained metering and portable designs.

Availability

MAX822SUS-T is available at Aetrix Electronics and suitable for portable medical instruments, industrial PLC I/O modules, smart energy meters, and bar-code scanners requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX822SUS-T 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 analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.

The MAX821/MAX822 family was engineered specifically for cost-sensitive, space-constrained microprocessor supervision in battery-powered and harsh-environment systems - prioritizing zero-external-component operation, wide temperature support, and glitch-immune reset generation.

FAQ

What is the exact reset threshold voltage of the MAX822SUS-T and how tightly is it specified?

The MAX822SUS-T has a nominal reset threshold of 2.93V, with a guaranteed tolerance of ±1.5% over the full operating temperature range (–40°C to +125°C). This specification is confirmed in the Electrical Characteristics table of the official datasheet (Rev 3, 19-1122), where MIN/MAX values are explicitly listed as 2.89V and 2.96V at TA = –40°C to +125°C. The MAX822SUS-T's tight threshold accuracy eliminates need for system-level calibration in 3V-class applications.

How does the SRT pin configure the reset timeout delay on the MAX822SUS-T?

The SRT pin on the MAX822SUS-T selects one of three discrete reset timeout periods: connect SRT to GND for 1ms (maximum), connect to VCC for 20ms (minimum), or leave unconnected for 100ms (minimum). This is implemented via internal resistor ladder decoding - no external timing components required. The MAX822SUS-T datasheet specifies that capacitive loading on SRT must remain below 200pF when left open to ensure reliable 100ms mode operation.

Does the MAX822SUS-T provide valid reset output when VCC drops below 1.5V?

Yes - the MAX822SUS-T guarantees valid active-high RESET output down to VCC = 1.2V, as confirmed in the Electrical Characteristics table (VCC Range row, MIN = 1.2V). Unlike many supervisors that fail below 2V, the MAX822SUS-T maintains defined VOH and VOL levels across this extended range, enabling robust brownout recovery in systems using aging or cold-temperature batteries where VCC may sag to 1.25V before cutoff.

What package type and footprint does the MAX822SUS-T use, and is it RoHS-compliant?

The MAX822SUS-T uses the SOT143-4 package (3.0mm × 1.5mm × 1.0mm), with package drawing code U4-1* per Maxim's ordering documentation. The "-T" suffix indicates tape-and-reel packaging; RoHS compliance is not inherent in the -T suffix - the MAX822SUS-T is leaded (non-RoHS), whereas MAX822SUS+T is the lead-free variant. The SOT143 footprint is standardized and widely supported in PCB design libraries.

Can the MAX822SUS-T replace the MAX822RUS-T in an existing design without changes?

No - the MAX822SUS-T and MAX822RUS-T have different reset thresholds (2.93V vs. 2.63V) and are not functionally interchangeable without verifying system-level brownout margins. While both share identical pinout, timing options, and package, substituting them requires validation that the 300mV higher trip point of the MAX822SUS-T does not cause premature reset in systems with tighter 3V rail regulation. The MAX822SUS-T datasheet explicitly lists these as distinct orderable variants with separate top marks (BJ_ vs. BK_).