TDC-GP22 - Ultrasonic Flow Converter with integrated Analog Frontend

TDC-GP22 is acam's newest product in the TDC product line. It is the first device that can be seen as an integrated ultrasonic flow converter. It is a 100% pin and functional compatible upgrade to TDC-GP21. But the new additional functionality - the save first hit detection and the patented signal strength monitoring by pulse width measurement - make it the first complete and easy to use front-end chip for ultrasonic water meters and heat meters.

Analog elements like a chopper stabilized comparator and analog switches simplify external circuits of ultrasonic flow meters in a significant manner. The programmable offset range of the comparator was extended. In combination with the first hit detection empty tubes can easily detected. In parallel, the operating current is reduced by improved internal data processing. All in all, the TDC-GP22 is the device of choice to design future ultra-compact and low-cost ultrasonic flow meters and heat meters.

TDC - Time-to-Digital Converters

TDC GP22 - Data Sheet

TDC-GP22

TDC	Resolution	Max Data Rate	Power Sup. (V)	Op. Temp.	Quiescent Curr.	INL	DNL
TDC GP22	typ. 90 ps, 45 ps in double resolution mode, 22 ps in quad resolution mode (only Measure Mode 2)	up to 1 M samples per second	2.5 V to 3.6 V	-40 °C to 125 °C	< 0.1 μA	< 0.1 LSB	< 0.8 LSB

GP22 - General Circuit Features

Measure Mode 2	Analog Input Circuit
1 channel with typ. 90 ps resolution Double resolution mode with 45 ps, Quad resolution mode with 22 ps resolution Measurement range 500 ns to 4 ms 3-fold multihit capability with automatic processing of all 3 data	Chopper-stabilized low-offset comparator, programmable, �35 mV First-wave detection: offset set zero automatically after first wave, hit selection relative to first wave First-wave pulse-width measurement for signal monitoring and bubble detection Integrated analog switches for input selection External circuit is reduced to 2 resistors and 2 capacitors
Special Functions	Temperature Measurement Unit
Fire pulse generator, up to 127 pulses Trigger to rising and/or falling edge Precise stop enable by windowing Low-power 32 kHz oscillator (500 nA) Clock calibration unit 7x32 Bit EEPROM	2 or 4 sensors, PT500/PT1000 or higher Schmitt trigger integrated 16-Bit eff. with external Schmitt-trigger, 17.5-Bit eff. with integrated low noise Schmitttrigger Ultra low current (0.08 �A when measuring every 30 seconds)
Measurement Mode 1	General
2 channels with typ. 90 ps resolution 1-channel double resolution with typ. 45 ps Range 3.5 ns (0 ns) to 2.5 �s 20 ns pulse-pair resolution, 4-fold multihit Up to 1 million measurements per second in measure mode 1	4-wire SPI interface 1 MHz continuous data rate max. I/O voltage 2.5 V to 3.6 V Core voltage 2.5 V to 3.6 V Temperature range � 40 �C to +125 �C QFN 32 package

TDC GP22 - Block Diagram and Package Outline

TDC Block Diagram	TDC Package Outline

Click image for closeup view

TDC Applications
Ultrasonic Heat Meters	Ultrasonic Flow Meters	Laser Range Finders
Laser Scanners	Magnetostrictive Positioning

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