EVALUATION KIT AVAILABLE
MAX35104
Gas Flow Meter SoC
General Description
Benefits and Features
● High Accuracy Flow Measurement for Billing and
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 differen-
tial time of flight (TOF), the device makes for simplified
computation of gaseous flow.
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
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 ampli-
fier chain amplifier, and an ultra-low input offset compara-
tor 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 measure-
ments and programmable receiver hit accumulators to
minimize the host microprocessor access. For tempera-
ture 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.
• 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
Ordering Information appears at end of data sheet.
Applications
● Ultrasonic Gas Meters
● Medical Ventilators
19-8501; Rev 3; 12/17