Gas Flow Meter SoC

Industry's First Integrated SOC Designed to Address the Unique Requirements of Natural Gas Meters

Please check latest availability status for a specific part variant.


The MAX35104 is a gas flow meter system-on-chip (SoC) targeted as an analog front-end solution for the ultrasonic gas meter and medical ventilator markets. With a time measurement accuracy of 700ps and automatic differential time of flight (TOF), the device makes for simplified computation of gaseous flow.

Power consumption is the lowest available with ultra-low 62µA time-of-flight measurement and 125nA duty-cycled temperature measurement. Multi-hit (up to six per wave) capability with stop-enable windowing allows the device to be fine-tuned for the application. Internal analog switches, a configurable three-stage integrated operational amplifier chain amplifier, and an ultra-low input offset comparator provide the analog interface and control for a minimal electrical bill of material solution. A programmable high-voltage (up to 30V) pulse launcher provides up to 19dB of transducer launch amplitude adjustment to compensate for transducer aging and temperature, pressure, humidity affects. Early edge detection ensures measurements are made with consistent wave patterns to greatly improve accuracy and eliminate erroneous measurements. Built-in arithmetic logic unit provides TOF difference measurements and programmable receiver hit accumulators to minimize the host microprocessor access. For temperature measurement, the device supports a single 2-wire PT1000 platinum resistive temperature detector (RTD) or NTC thermistor. A simple 4-wire SPI interface allows any microcontroller to effectively configure the device for its intended measurement.
MAX35104: Block Diagram MAX35104: Block Diagram Enlarge+

Key Features

  • High Accuracy Flow Measurement for Billing and Leak Detection
    • Time-to-Digital Accuracy Down to 700ps Measurement Range Up to 8ms
    • 2 Channels: Single-Stop Channel
  • High Accuracy Temperature Measurement for Precise Flow Calculations
    • One 2-Wire Sensor: PT1000, PT500 RTD, and Thermistor Support
  • Maximizes Battery Life with Low Device and Overall System Power
    • Ultra-Low 62µA TOF Measurement and 125nA Duty-Cycled Temperature Measurement
    • Event Timing Mode with Randomizer Reduces Host µC Overhead to Minimize System Power Consumption
    • 2.3V to 3.6V Single-Supply Operation
  • High Integration Solution Minimizes Parts Count and Reduces BOM Cost
    • Built-In Real-Time Clock
    • Small, 5mm x 5mm, 40-Pin TQFN Package
    • -40°C to +85°C Operation
  • Applications/Uses

    • Medical Ventilators
    • Ultrasonic Gas Meters

    See parametric specs for Sensor Signal Conditioners (10)

    Part NumberSensing ElementPGA GainCalibration MethodOutput TypeICC
    typSee Notes
    Ultrasonic Piezoelectric Transducer
    Ultrasonic Transducer
    10 to 29.95 (16 gains)External microcontrollerDigital0.006SPI2.3 to 3.6
    $6.63 @1k

    Pricing Notes:
    This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

    MAX35104EVKIT: Evaluation Kit for the MAX35104
    MAX35104EVKIT2: Evaluation Kit for the MAX35104

    Tools & Models

  • MAX35104
  • Request Reliability Report for: MAX35104 
    Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

    Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

    Quality Management System >
    Environmental Management System >


    Related Resources