Reduced Power Time-to-Digital Converter with AFE, RTC, and Flash

Accurate Low Flow Measurement with Lowest System Power Consumption

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The MAX35103 is a time-to-digital converter with built-in amplifier and comparator targeted as a low-cost analog front-end solution for the ultrasonic heat meter and flow meter markets. It is similar to the MAX35101, but consumes about half the average power and increases the maximum ToF measurement frequency in event timing mode from 2Hz to 16Hz.

With a time measurement accuracy of 20ps and automatic differential time-of-flight (ToF) measurement, this device makes for simplified computation of liquid flow.

Average power consumption is the lowest available with ultra-low 5.5μA ToF measurement and < 125nA duty-cycled temperature measurement.
MAX35103: Typical Application Circuit MAX35103: Typical Application Circuit Enlarge+

Key Features

  • High Accuracy Flow Measurement for Billing and Leak Detection
    • Time-to-Digital Accuracy Down to 20ps
    • Measurement Range Up to 8ms
    • Two Channels: Single-Stop Channel
  • High Accuracy Temperature Measurement for Precise Heat and Flow Calculations
    • Up to Four 2-Wire Sensors
    • PT1000 and PT500 RTD Support
  • Maximizes Battery Life with Low Device and Overall System Power
    • Ultra-Low 5μA ToF Measurement and < 125nA Duty-Cycled Temperature Measurement
    • Event Timing Mode Reduces Host Microcontroller Overhead to Minimize System Power Consumption
    • 2.3V to 3.6V Single-Supply Operation
  • High-Integration Solution Minimizes Parts Count and Reduces BOM Cost
    • 8KB of Nonvolatile Flash Memory for Data Logging
    • Built-in Real Time Clock
    • Small, 5mm x 5mm, 32-Pin TQFP Package
    • -40°C to +85°C Operation


  • Ultrasonic Gas Meters
  • Ultrasonic Heat Meters
  • Ultrasonic Water Meters
Part NumberSensing ElementPGA GainCalibration MethodOutput TypeICC
typSee Notes
MAX35103 Ultrasonic Piezoelectric TransducerFixedExternal microcontrollerDigital0.006SPI2.3 to 3.6
$4.73 @1k
See All Sensor Signal Conditioners (10)
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.

MAX35103EVKIT: Evaluation Kit for the MAX35103
MAX35103EVKIT2: Evaluation Kit for the MAX35103/MAX32620

CAD Symbols and Footprints

  • MAX35103EHJ+
  • MAX35103EHJ+T
  • Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

    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.

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