Analog Devices Inc./Maxim Integrated MAX6802UR29D1+T

Overview

MAX6802UR29D1+T from Maxim Integrated is an open-drain, active-low microprocessor supervisory circuit in a 3-pin SOT23 package, designed to monitor 2.93V power supplies and assert reset for ≥1ms after VCC rises above threshold. It operates down to 1.0V supply, draws only 4–12µA, and provides transient-immune brownout detection for embedded controllers and portable systems.

For engineers reviewing the MAX6802UR29D1+T datasheet, MAX6802UR29D1+T pinout, MAX6802UR29D1+T application, or MAX6802UR29D1+T equivalent, key selection criteria include its 2.93V factory-trimmed reset threshold, 1ms minimum timeout, open-drain output structure, guaranteed operation to 1.0V, and compatibility with bidirectional µP reset pins.

Technical Context

The MAX6802UR29D1+T implements a precision voltage comparator with ±1.8% threshold accuracy at +25°C and ±3% over –40°C to +125°C, paired with a fixed 1ms reset timeout timer. Its open-drain RESET output requires an external pullup resistor and supports wired-OR configurations with microcontrollers having bidirectional reset pins.

It features immunity to fast VCC transients (e.g., ≤30µs glitches at 100mV overdrive), operates across full industrial temperature range (–40°C to +125°C), and maintains valid reset state down to VCC = 1.0V-unlike the MAX6800/MAX6801 which guarantee down to 0.7V.

Key Specifications

Pinout & Package

MAX6802UR29D1+T is housed in a RoHS-compliant 3-pin SOT23 package (outline 21-0051, land pattern 90-0179), with 1.3mm × 2.9mm footprint and 0.95mm height-optimized for space-constrained PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6802UR29D1+T, the MAX6326UT29D1+T sacrifices high-temperature operation for lower unit cost, while the TPS3808G125DBVR trades open-drain versatility and sub-1.2V validity for integrated push-pull drive-making MAX6802UR29D1+T optimal for thermally demanding, multi-source reset bus designs.

Availability

MAX6802UR29D1+T is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical devices, automotive body control modules, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6802UR29D1+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, automotive, and communications markets.

The MAX6800/MAX6801/MAX6802 family delivers ultra-low-power, pin-compatible supervisory circuits for space-constrained µP systems requiring precise, glitch-immune reset generation across harsh operating conditions.

FAQ

What is the exact reset threshold voltage of MAX6802UR29D1+T and how tightly is it specified?

The MAX6802UR29D1+T has a factory-trimmed nominal reset threshold of 2.93V, with tolerance of ±1.8% at +25°C and ±3% over the full –40°C to +125°C temperature range. This precision eliminates need for external calibration and ensures consistent brownout detection across environmental extremes. The 2.93V value is selected from Table 1 in the datasheet and confirmed in the Selector Guide for UR29 suffix.

Does MAX6802UR29D1+T support operation down to 0V VCC, and what happens below 1.0V?

No-MAX6802UR29D1+T is guaranteed functional only down to VCC = 1.0V. Below that, reset assertion cannot be assured due to reduced sinking capability of the open-drain output. Unlike push-pull variants (MAX6800/MAX6801), the MAX6802UR29D1+T is not recommended for applications requiring valid reset down to 0V; a pulldown resistor will not restore guaranteed behavior in that region.

What is the purpose of the "D1" in MAX6802UR29D1+T, and how does it affect timing behavior?

The "D1" in MAX6802UR29D1+T denotes a factory-programmed minimum reset timeout period of 1ms. This is distinct from D2 (20ms min) and D3 (100ms min). The 1ms timeout ensures rapid system recovery after brief brownouts while still meeting µP internal stabilization requirements-critical in real-time control loops and battery-powered wake-up sequences.

Can MAX6802UR29D1+T drive a reset line shared with other open-drain devices, and what pullup value is recommended?

Yes-MAX6802UR29D1+T's open-drain RESET output is explicitly designed for wired-OR bus sharing, such as with µP bidirectional reset pins (e.g., Motorola 68HC11). A 10kΩ to 100kΩ pullup resistor to VCC is recommended; 47kΩ is typical for balancing speed, noise immunity, and current draw. Total bus capacitance should remain <50pF to maintain <1µs rise time.

How does MAX6802UR29D1+T reject power-supply transients, and what is its maximum tolerable glitch width?

MAX6802UR29D1+T rejects fast VCC transients via internal hysteresis and comparator overdrive filtering. Per the "Maximum Transient Duration vs. Reset Comparator Overdrive" graph, it tolerates ≤30µs negative-going glitches at 100mV overdrive without asserting reset. This immunity prevents spurious resets in electrically noisy environments like motor drives or switching power supplies.