Analog Devices Inc./Maxim Integrated MAX6334UR20D3-T

Overview

MAX6334UR20D3-T from Maxim Integrated is an open-drain, active-low microprocessor supervisory circuit in a 3-pin SOT23 package, designed for reliable power-on reset generation in 1.8V–3.3V digital systems. It asserts RESET when VCC falls below 2.00V (±1.8% at +25°C), maintains it for ≥100ms after VCC recovers, draws only 3.3µA at 2.5V, and operates down to VCC = 1.0V over –40°C to +125°C - enabling use in battery-powered instrumentation and critical μP monitoring.

For engineers reviewing the MAX6334UR20D3-T datasheet, MAX6334UR20D3-T pinout, MAX6334UR20D3-T application, or MAX6334UR20D3-T equivalent, key selection criteria include its factory-trimmed 2.0V reset threshold, 100ms minimum timeout, open-drain output for bidirectional μP reset interfaces, guaranteed operation to 1.0V supply, and immunity to fast VCC transients up to 24µs.

Technical Context

The MAX6334UR20D3-T implements a precision voltage comparator with hysteresis and a fixed internal timeout timer. Its reset assertion logic is triggered solely by VCC falling below the 2.00V threshold, with propagation delay of 24µs (at 10V/ms VCC fall rate), and the open-drain output requires an external pull-up resistor for proper level translation and bidirectional reset arbitration.

Unlike push/pull variants (MAX6332/MAX6333), this device's open-drain architecture enables wired-OR reset bus configurations and direct interfacing with microcontrollers like the Motorola 68HC11 that feature bidirectional reset pins - eliminating need for external logic or isolation components.

Key Specifications

Pinout & Package

MAX6334UR20D3-T is housed in a RoHS-compliant 3-pin SOT23 package (outline 21-0051) with standard land pattern 90-0179. The package is tape-and-reel only and supports both leaded and lead-free assembly (–T suffix denotes lead-free).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6334UR20D2-T and MAX6327UT20D3-T, the MAX6334UR20D3-T uniquely combines 2.0V threshold, 100ms timeout, open-drain output, and guaranteed 1.0V operation - making it optimal for battery-powered systems needing robust brownout protection and bidirectional reset capability.

Availability

MAX6334UR20D3-T is available at Aetrix Electronics and suitable for portable instrumentation, industrial controllers, intelligent sensors, and automotive body electronics requiring stable component supply and long-term lifecycle support.

Supply support for MAX6334UR20D3-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) designs precision analog, mixed-signal, and power management ICs for industrial, automotive, communications, and computing applications.

The MAX6332/MAX6333/MAX6334 family delivers ultra-low-voltage, low-power μP supervisory circuits targeting space-constrained, battery-operated, and high-reliability embedded systems requiring precise reset control without external components.

FAQ

What is the exact reset threshold voltage of MAX6334UR20D3-T and how tightly is it specified?

The MAX6334UR20D3-T has a factory-trimmed nominal reset threshold of 2.00V, with a tolerance of ±1.8% at +25°C and ±3% over the full –40°C to +125°C temperature range. This specification ensures accurate brownout detection for 1.8V and 2.5V power rails without external calibration. The MAX6334UR20D3-T's tight threshold control eliminates need for trimming resistors or post-production adjustment.

Does MAX6334UR20D3-T support operation at VCC below 1.8V, and what is its minimum functional supply voltage?

Yes, the MAX6334UR20D3-T is guaranteed to operate correctly down to VCC = 1.0V across –40°C to +125°C, unlike push/pull variants which require ≥0.7V. This makes the MAX6334UR20D3-T suitable for deep brownout monitoring in battery-powered systems where supply may dip near 1.0V before shutdown. Its open-drain output remains functional throughout this range when used with appropriate pull-up.

What is the purpose of the "D3" suffix in MAX6334UR20D3-T, and how does it affect timing behavior?

The "D3" suffix in MAX6334UR20D3-T indicates a factory-programmed minimum reset timeout period of 100ms. This value is fixed and non-adjustable - ensuring consistent, reliable reset hold time for μP initialization without external capacitors. The MAX6334UR20D3-T's 100ms timeout exceeds typical ARM Cortex-M or PIC boot requirements and provides margin against supply instability during recovery.

Can MAX6334UR20D3-T interface directly with a microcontroller that has a bidirectional reset pin, and what external component is required?

Yes, the MAX6334UR20D3-T's open-drain RESET output is specifically designed for direct interface with bidirectional μP reset pins (e.g., Motorola 68HC11). A single external pull-up resistor (typically 10kΩ–100kΩ to VCC) is required to establish the high state. This configuration allows either the MAX6334UR20D3-T or the μP to assert reset on the shared line - no level shifters or logic gates are needed.

How does MAX6334UR20D3-T reject short-duration supply transients, and what is its maximum tolerable glitch width?

The MAX6334UR20D3-T incorporates internal hysteresis and comparator filtering to reject fast negative-going VCC transients. At 10mV overdrive (i.e., VCC dipping 10mV below 2.00V), it tolerates glitches up to 24µs without asserting reset. This immunity prevents false resets caused by switching noise or ESD events. The MAX6334UR20D3-T's transient rejection is characterized across temperature and documented in its Typical Operating Characteristics graph.