TDC-GP21: Time-to-Digital Converter with Integrated Analog Frontend

• 2-channel TDC with 22ps resolution
• Analog frontend for ultrasonic flow meters
• Chopper-stabalized low-offset comparator for zero crossing detection
• Precise windowing for hit selection
• Temperature measuring unit for PT1000 sensors
• QFN32 package

TDC-GP21 BENEFITS

• High prescision
• Low power
• Few additional external component needed

Measurement Mode 1

• 2 channels with typ. 90 ps resolution
• 1-channel double resolution with typ. 45 ps
• Range 3.5 ns (0 ns) to 2.5 µs
• 20 ns pulse-pair resolution, 4-fold multihit
• Up to 1 million measurements per second in measure mode 1

Measurement Mode 2

• 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
• 2 x CLKHS pulse-pair resolution with 3-fold multihit capability
• Each of the 3 events can be assigned to an adjustable measuring window with 10 ns resolution

Temperature Measurement Unit

• 2 or 4 sensors
• PT100/PT500/PT1000 or higher
• Schmitt trigger integrated
• Very high resolution: up to 17.5 Bit eff. (0.004 °C resolution for platinum sensors)
• Ultra low current (0.08 µA when measuring every 30 seconds)

Special Functions

• 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
• 7×32 Bit EEPROM

Analog Input Circuit

• Chopper-stabilized low-offset comparator
• 2 analog switches for input selection
• External circuit is reduced to 2 resistors and 2 capacitors

FUNCTIONAL BLOCK DIAGRAM

Resolution
typ. 90 ps, 45 ps in double resolution mode, 22 ps in quad resolution mode (only Measure Mode 2)

Max data rate:	up to ½ million samples per second
Power supply voltage:	2.5 V to 3.6 V
Operating temp:	-40°C to 125°C
Quiescent current:	< 0.1µA
INL:	< 0.1 LSB
DNL:	< 0.8 LSB