Analog Devices Inc./Maxim Integrated MAX6802UR31D3+

Overview

MAX6802UR31D3+ from Maxim Integrated is an open-drain, active-low microprocessor supervisory circuit designed for power supply monitoring in 2.85V–5.0V digital systems. It asserts reset when VCC falls below 3.08V (±3% over temperature), maintains reset for ≥100ms after VCC recovers, operates down to 1.0V supply, draws only 4–12µA, and is housed in a 3-pin SOT23 package for space-constrained embedded controllers.

For engineers reviewing the MAX6802UR31D3+ datasheet, MAX6802UR31D3+ pinout, MAX6802UR31D3+ application, or MAX6802UR31D3+ equivalent, key selection criteria include its 3.08V factory-trimmed reset threshold, 100ms minimum timeout, open-drain output compatibility with bidirectional µP reset pins (e.g., Motorola 68HC11), and guaranteed operation down to VCC = 1.0V - critical for brownout detection in portable and industrial equipment.

Technical Context

The MAX6802UR31D3+ implements a precision bandgap-based reset comparator with factory-trimmed 3.08V threshold (±1.8% at +25°C, ±3% over –40°C to +125°C) and built-in immunity to fast VCC transients (e.g., ≤30µs glitches at 100mV overdrive). Its open-drain RESET output requires an external pullup and sinks up to 1.2mA at VCC ≥ 2.5V with VOL ≤ 0.3V.

It features a fixed 100ms (min) reset timeout period, no external components required, and operates across –40°C to +125°C with full electrical specification. The BiCMOS process ensures low 4–12µA supply current and stable performance without trimming or calibration.

Key Specifications

Pinout & Package

MAX6802UR31D3+ is packaged in a RoHS-compliant 3-pin SOT23 (U3-1) with 1.3mm × 2.9mm footprint and 0.95mm height - optimized for high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6802UR31D3+, MAX6327LT29D3+ offers simpler drive but lacks open-drain flexibility, while TPS3808G33DBVR provides timeout adjustability at the cost of pin count, size, and power - making MAX6802UR31D3+ optimal for space-constrained, multi-device reset buses in industrial and portable designs.

Availability

MAX6802UR31D3+ is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical monitors, and automotive body control modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX6802UR31D3+ 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, mixed-signal, and power management ICs for industrial, automotive, and communications applications - emphasizing reliability, integration, and low-power operation.

The MAX6800/MAX6801/MAX6802 family delivers ultra-low-power, pin-compatible µP supervisors with factory-trimmed thresholds and fixed timeouts - engineered for cost-sensitive, space-constrained embedded systems needing robust power monitoring without external components.

FAQ

What is the exact reset threshold voltage of the MAX6802UR31D3+?

The MAX6802UR31D3+ has a factory-trimmed nominal reset threshold of 3.08V, with tolerance of ±1.8% at +25°C and ±3% over the full operating temperature range of –40°C to +125°C. This value is confirmed in Table 1 of the official datasheet and applies specifically to the "31" suffix variant, not other members of the MAX6802 family.

Does the MAX6802UR31D3+ require an external pullup resistor on the RESET pin?

Yes, the MAX6802UR31D3+ features an open-drain RESET output and requires an external pullup resistor (typically 10–100kΩ) to VCC or another logic rail. Without it, the RESET signal cannot achieve a defined high state. This design enables wired-OR configurations and compatibility with microcontrollers like the Motorola 68HC11 that have bidirectional reset pins.

What is the minimum supply voltage at which the MAX6802UR31D3+ guarantees correct reset operation?

The MAX6802UR31D3+ guarantees correct RESET/RESET output state down to VCC = 1.0V - unlike the MAX6800/MAX6801 variants, which guarantee operation only to 0.7V. This is explicitly stated in the General Description and Electrical Characteristics sections of the datasheet and reflects the device's internal architecture optimization for open-drain output stability.

Can the MAX6802UR31D3+ be used in automotive applications?

Yes, the MAX6802UR31D3+ is rated for operation from –40°C to +125°C and specified across this full range, making it suitable for under-hood and cabin automotive applications such as body control modules. Its transient immunity (e.g., rejection of ≤30µs VCC glitches) and guaranteed 1.0V operation further support robustness in automotive power environments.

How does the 100ms reset timeout of the MAX6802UR31D3+ compare to other timeout options in the MAX6802 family?

The "D3" suffix in MAX6802UR31D3+ denotes a factory-programmed 100ms (minimum) reset timeout period. Other variants include D1 (1ms min) and D2 (20ms min). All three timeouts are fully specified over temperature and do not require external components - the D3 version is selected when µP and peripheral initialization times exceed 20ms, ensuring safe release after full system stabilization.