Analog Devices Inc./Maxim Integrated MAX6802UR46D3

Overview

MAX6802UR46D3 from Maxim Integrated is an open-drain, active-low microprocessor supervisory circuit in a 3-pin SOT23 package, designed to monitor 4.63V power supplies with ±3% threshold accuracy over -40°C to +125°C and assert reset for ≥100ms after VCC recovery. It draws only 5µA typical supply current at 5V and guarantees valid RESET output down to VCC = 1.0V. Used in automotive and industrial controllers for brownout protection.

For engineers reviewing the MAX6802UR46D3 datasheet, MAX6802UR46D3 pinout, MAX6802UR46D3 application, or MAX6802UR46D3 equivalent, key selection criteria include its factory-trimmed 4.63V reset threshold, 100ms minimum timeout, open-drain output architecture, guaranteed operation down to 1.0V VCC, and immunity to sub-30µs VCC transients at 100mV overdrive.

Technical Context

The MAX6802UR46D3 implements a precision bandgap-based voltage comparator with hysteresis to detect VCC falling below 4.63V (±3% over temperature), triggering an open-drain RESET assertion. Its internal timing circuit generates a fixed ≥100ms reset pulse after VCC rises above threshold, independent of external components.

Designed for high-noise environments, the reset comparator rejects fast transients-e.g., a 100mV dip on VCC must exceed ~30µs to trigger reset. The open-drain output requires an external pullup resistor and supports bidirectional reset interfaces, such as with Motorola 68HC11 microcontrollers.

Key Specifications

Pinout & Package

MAX6802UR46D3 is housed in a RoHS-compliant 3-pin SOT23 package (outline U3-1, land pattern 90-0179), with 1.3mm × 0.8mm 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 MAX6801UR46D3-T and MAX6328UT46D3-T, the MAX6802UR46D3 uniquely combines automotive temperature rating, open-drain flexibility, and guaranteed 1.0V VCC operation - making it the only choice for shared-reset systems in harsh environments.

Availability

MAX6802UR46D3 is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC controllers, portable medical devices, and smart sensor nodes requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6802UR46D3 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 demanding industrial, automotive, and computing applications.

The MAX6800/MAX6801/MAX6802 family delivers highly integrated, low-power microprocessor supervisory circuits targeting space- and reliability-critical systems where external component count and supply noise immunity are paramount.

FAQ

What is the exact reset threshold voltage of MAX6802UR46D3 and how tightly is it specified?

The MAX6802UR46D3 has a factory-trimmed reset threshold of 4.63V, with a guaranteed tolerance of ±3% over the full operating temperature range of -40°C to +125°C. At +25°C, the typical value is 4.63V, and the min/max limits are 4.491V and 4.769V respectively. This precision eliminates the need for external calibration and ensures consistent brownout detection across environmental conditions.

Does MAX6802UR46D3 support operation at very low supply voltages, and what is the minimum functional VCC?

Yes, the MAX6802UR46D3 is guaranteed to maintain correct RESET/RESET logic states down to VCC = 1.0V, unlike the MAX6800/MAX6801 variants which are rated to 0.7V. This ensures deterministic reset behavior during deep brownout events, though the open-drain output's sinking capability degrades below 1.0V - so system design should ensure critical reset actions complete above this threshold.

What is the purpose of the open-drain output in MAX6802UR46D3, and what external component is required?

The open-drain output of the MAX6802UR46D3 enables wired-OR reset bus configurations and direct interface with microcontrollers featuring bidirectional reset pins (e.g., Motorola 68HC11). It requires an external pullup resistor - typically 10kΩ to 100kΩ - connected between the RESET pin and the target logic rail (e.g., VCC or 3.3V). No pullup is integrated internally.

How long does the reset pulse last on MAX6802UR46D3 after VCC recovers above the threshold?

The MAX6802UR46D3 asserts RESET for a minimum of 100ms after VCC rises above the 4.63V threshold. This timeout is factory-programmed and fully specified over temperature; typical values range from 100ms to 200ms depending on process variation. The fixed duration ensures sufficient time for power stabilization and oscillator startup in connected microprocessors.

Can MAX6802UR46D3 reject fast supply transients, and what is its transient immunity specification?

Yes, the MAX6802UR46D3 reset comparator is designed to ignore fast negative-going VCC transients. It rejects pulses ≤30µs in duration when the overdrive is 100mV below the 4.63V threshold. This immunity is confirmed by the "Maximum Transient Duration vs. Reset Comparator Overdrive" curve in the datasheet and prevents spurious resets caused by switching noise or ESD-induced supply disturbances.