AS6040 Ultrasonic Flow Converter

AS6040 is an ultrasonic flow converter (UFC) solution dedicated to gas meters, but suitable for water meters, too.

It is made up of four main parts: the supervisor, the front end, the post-processing unit, and the interface. The supervisor is the master of the system and controls all of the other parts, making the AS6040 autonomous. 

The front end has a high-voltage driver, an integrated PGA, an offset-stabilized comparator in the receive path, a precision TDC for the time-of-flight measurement, amplitude measurement, and an RDC unit for temperature measurement. 

In flow meter mode, the 32-bit CPU and the post-processing unit calculate the flow. In time conversion mode, the CPU is inactive, and the chip sends the raw time-of-flight data. 

The AS6040 communicates with an external microcontroller via SPI interface. It can also run in stand-alone mode using the integrated pulse interface.

Blockdiagram AS6040 Ultrasonic Flow Converter

AS6040 features and benefits

Features:

  • High performance + ultra-low power 32-Bit CPU
  • 120 * 32 bit NVRAM (non-volatile RAM) for user firmware parameter & data
  • 3968 * 8 bit NVRAM (non-volatile RAM) for user firmware program code
  • 4k * 8 bit ROM for system task code and special flow library code
  • 50 kHz to 1 MHz at 6 V to 17 V drive voltage, generated from battery supply
  • Integrated PGA, gain 2 to 200
  • First hit level and phase detection
  • Amplitude measurement
  • Up to 31 zero crossing measurements
  • Precision time-to-digital converter and low-noise front-end with < 50 ps single shot with good 1MHz transducers on a DN20
  • Ultra-low power consumption
  • SPI serial interface

Benefits:

  • Single-chip solution provides ready flow information
  • System design compatible with mechanical meters
  • High flexibility in choice for external µP handling communication and further data management
  • Operation from Battery
  • Precision down to low flow rates
  • Leakage detection
  • Handles weak signals for small transducers and multiple reflections
  • Compact design
  • Low BOM

Product properties

  • Analog Frontend Yes, with PGA and HV charge pump
  • First Wave Detection Yes, split burst
  • Amplitude Measurement Yes
  • Number of hits 31
  • Resolution TDC [ps] 22
  • Operating Supply Range 3.0 to 3.6
  • Interface SPI, Pulse, 2-wire master
  • CPU 32-bit
  • Firmware -
  • Memory 4k NVRAM, 4k ROM
  • GPIO 5
  • Ambient Temperature Range [°C] -40 to +85
  • Package QFN48

Applications

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Related Tools

Development kit

The AS6040 development kit allows customers a quick and intuitive approach to using the AS6040 UFC in ultrasonic flow meter applications.