Analog Devices Inc./Maxim Integrated MAX6347XR33-T

Overview

MAX6347XR33-T from Maxim Integrated is an active-high push-pull microprocessor supervisory circuit designed to monitor 3.3V power supplies and assert a reset signal during brownout, power-up, and power-down events. It features a factory-trimmed 3.30V reset threshold (±1.5% at +25°C, ±2.5% over -40°C to +85°C), 100ms minimum reset timeout, ultra-low 1µA max supply current, and guaranteed operation down to VCC = 1.2V. It is used in portable battery-powered systems requiring reliable, low-power power-on reset functionality.

For engineers reviewing the MAX6347XR33-T datasheet, MAX6347XR33-T pinout, MAX6347XR33-T application, or MAX6347XR33-T equivalent, key selection criteria include active-high push-pull output logic, SC70-3 package compatibility, 3.3V supply monitoring accuracy, transient immunity against sub-200µs VCC glitches, and drop-in replacement capability for legacy MAX809/MAX810-based designs.

Technical Context

The MAX6347XR33-T implements a precision bandgap-based voltage comparator with hysteresis (9.5mV) to detect VCC falling below its 3.30V threshold, triggering an active-high RESET output that remains asserted for ≥100ms after VCC recovers. Its internal reference is trimmed at wafer level to ensure ±1.5% accuracy at room temperature and ±2.5% across full industrial temperature range.

It operates from 1.2V to 5.5V VCC, draws ≤1.0µA at 3V (typical 0.5µA), and maintains correct reset state down to 1V - enabling robust brownout detection even during deep discharge. The push-pull output drives high (≥0.8·VCC at 500µA source) when reset is inactive and low (≤0.3V at 1.2mA sink) when asserted, eliminating external pull-up requirements.

Key Specifications

Pinout & Package

MAX6347XR33-T is housed in a 3-pin SC70-3 package (outline X3-2, land pattern 90-0208), measuring 2.0mm × 2.1mm × 0.95mm, with gull-wing leads and RoHS-compliant lead-free finish (marked "FZBJ").

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6347XR33-T, MAX809TRD3-T requires external biasing and offers no current advantage, while TPS3808G33DBVR trades 1.5µA higher supply current and longer reset hold for TI's broader qualification and longer production support - making MAX6347XR33-T optimal for space-constrained, battery-critical designs needing minimal ICC and exact SC70-3 fit.

Availability

MAX6347XR33-T is available at Aetrix Electronics and suitable for portable medical monitors, industrial PLC I/O modules, smart energy meters, and automotive body control modules requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for MAX6347XR33-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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.

The MAX63xx family was engineered specifically for ultra-low-power, precision power-supply supervision in battery-operated and space-constrained embedded systems - emphasizing minimal ICC, tight threshold tolerance, and robust transient rejection.

FAQ

What is the exact reset threshold voltage of MAX6347XR33-T and how tightly is it specified?

The MAX6347XR33-T has a nominal reset threshold of 3.30V, factory-trimmed to ±1.5% at +25°C and ±2.5% over the full -40°C to +85°C operating temperature range. This specification is guaranteed per datasheet Electrical Characteristics table and applies directly to the MAX6347XR33-T - not inferred from family data. Threshold hysteresis is 9.5mV, ensuring clean transition without oscillation near trip point.

Does MAX6347XR33-T require an external pull-up resistor on its RESET pin?

No, MAX6347XR33-T does not require an external pull-up resistor because it features an active-high push-pull output. Its RESET pin actively drives high (≥0.8·VCC at 500µA source) when the supply is valid and low (≤0.3V at 1.2mA sink) during reset assertion. This eliminates BOM cost, saves PCB area, and removes a potential failure point compared to open-drain alternatives like MAX6348XR33-T.

What is the minimum VCC voltage at which MAX6347XR33-T guarantees correct reset state?

MAX6347XR33-T guarantees correct reset assertion and deassertion behavior down to VCC = 1.2V over the full -40°C to +85°C temperature range. While the device remains functional (comparator operational) down to 1.0V, the 1.2V lower limit is the guaranteed minimum for reliable reset state control per datasheet Absolute Maximum and Operating Conditions tables - critical for brownout detection in Li-ion battery systems.

How does MAX6347XR33-T handle fast transients on the VCC line?

MAX6347XR33-T incorporates internal transient immunity circuitry that rejects fast negative-going VCC transients up to 200µs in duration when the overdrive (VTH – VCC) is 100mV, as shown in Figure 4 of the datasheet. This prevents false resets caused by switching noise, ESD coupling, or load-step artifacts - a design feature validated across production lots and explicitly characterized for the MAX6347XR33-T variant.

Is MAX6347XR33-T pin-compatible with industry-standard supervisory ICs like MAX809?

Yes, MAX6347XR33-T is pin-compatible with MAX809TRD3-T and MAX810LRT33-T in the SC70-3 package: Pin 1 = GND, Pin 2 = RESET, Pin 3 = VCC. However, MAX6347XR33-T differs in output logic (active-high push-pull vs. MAX809's active-low open-drain), so direct substitution requires verification of µP reset pin polarity and removal of any existing pull-up resistor.