Analog Devices Inc./Maxim Integrated MAX6346UR33

Overview

MAX6346UR33 from Maxim Integrated is a push-pull active-low microprocessor supervisory circuit designed for precision 3.3V power-supply monitoring in embedded systems. It asserts reset when VCC falls below 3.30V (±1.5% at +25°C, ±2.5% over -40°C to +85°C), maintains reset for ≥100ms after VCC recovery, draws ≤1µA supply current, and operates down to 1.2V VCC. It is used in portable battery-powered controllers requiring reliable brownout protection.

For engineers reviewing the MAX6346UR33 datasheet, MAX6346UR33 pinout, MAX6346UR33 application, or MAX6346UR33 equivalent, key selection criteria include its factory-trimmed 3.30V reset threshold, SOT23-3 package compatibility, push-pull output drive capability (VOH ≥ 0.8·VCC at ISOURCE = 500µA), and immunity to fast VCC transients up to 100V/µs slew rate.

Technical Context

The MAX6346UR33 implements a precision bandgap-based reset comparator with 40ppm/°C temperature coefficient and 9.5mV hysteresis, ensuring stable threshold behavior across industrial temperature range (-40°C to +85°C). Its internal timing circuit guarantees minimum 100ms reset timeout after power-up, independent of external components.

As a member of the MAX6346 family, it shares identical electrical architecture with MAX6326 but features tighter reset threshold tolerances and optimized transient rejection-specifically rejecting negative-going VCC glitches up to 200µs duration when overdriven by 100mV below VTH, per Typical Operating Characteristics data.

Key Specifications

Pinout & Package

SOT23-3 package: 2.92mm × 1.3mm × 1.02mm body, gull-wing leads, RoHS-compliant lead-free option available (replace "-T" with "+T").

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326UR33, MAX6346UR33 offers identical form-factor and function but tighter initial threshold accuracy (±1.5% vs. ±2.5% at +25°C), making it preferable for precision 3.3V systems; versus TPS3123-33DBVR, MAX6346UR33 delivers lower ICC, push-pull output, and faster release timing - critical for battery-constrained and high-speed boot applications.

Availability

MAX6346UR33 is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical sensors, smart energy meters, and automotive body control modules requiring stable component supply and long-term production continuity.

Supply support for MAX6346UR33 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 and mixed-signal ICs for industrial, computing, and communications applications, with emphasis on power management and reliability-critical functions.

The MAX6346 series belongs to Maxim's ultra-low-power µP supervisory product line, engineered specifically for battery-operated and noise-prone embedded systems requiring guaranteed reset behavior without external components.

FAQ

What is the exact reset threshold voltage of MAX6346UR33 and how does it vary with temperature?

The MAX6346UR33 has a factory-trimmed nominal reset threshold of 3.30V, specified as ±1.5% at +25°C and ±2.5% over the full -40°C to +85°C operating range. Its temperature coefficient is 40ppm/°C, meaning threshold drift is limited to approximately ±10mV across the industrial temperature span - verified in the Electrical Characteristics table under VTH conditions.

Does MAX6346UR33 require any external components to operate?

No, MAX6346UR33 requires zero external components. It integrates the voltage reference, comparator, timing capacitor, and push-pull output driver in a single SOT23-3 package. Unlike discrete reset solutions, it needs no pull-up resistors, timing capacitors, or trimming potentiometers - confirmed in the General Description and Features sections.

What is the maximum VCC slew rate that MAX6346UR33 can tolerate without generating false resets?

MAX6346UR33 is rated for VCC slew rates up to 100V/µs, as stated in the Absolute Maximum Ratings table. Its internal comparator design rejects fast transients, and the Typical Operating Characteristics graph "Maximum Transient Duration vs. Reset Threshold Overdrive" confirms immunity to negative glitches ≤200µs when overdriven by 100mV - enabling reliable operation in switch-mode power supply environments.

Can MAX6346UR33 be used with a 1.2V supply, and what is its behavior below the reset threshold?

Yes, MAX6346UR33 is fully functional down to VCC = 1.2V (minimum specified in Electrical Characteristics), and its reset output remains asserted (low) as long as VCC stays below 3.30V. The device guarantees correct logic state for VCC ≥ 1.0V, and the reset comparator continues monitoring even during deep brownout - per the General Description statement "guaranteed to be in the correct state for VCC down to 1V."

Is MAX6346UR33 pin-compatible with legacy Maxim reset ICs like MAX809?

Yes, MAX6346UR33 is explicitly stated as pin compatible with MAX803/MAX809/MAX810 in the Features section. All share identical SOT23-3 pinout (VCC, RESET, GND), same 3.3V threshold option, and push-pull active-low output - enabling drop-in replacement in existing designs without PCB modification.