AS6501 Time-to-Digital Converter

AS6501 Time-to-Digital Converter

The AS6501 is a high performance 2-channel time-to-digital converter (TDC) frontend device based and derived from TDCGPX2. Highest measurement performance and highest data throughput is achieved with LVDS stop inputs and LVDS serial outputs for each channel.

2-Channel TDC with LVDSA Inputs/Outputs

Current saving operation is also possible with CMOS inputs and SPI readout. High configuration flexibility and unlimited measurement range cover many applications. They range from portable handheld laser range equipment to ambitious time-of-flight measurements of highest performance, as e.g. done in medical imaging applications. AS6501 operates without any locked loop technologies. 

AS6501 calculates all stop measurements inside, proportional to the applied reference clock. Combinations of best single shot accuracy of 10 ps with lowest pulse-to-pulse spacing <5 ns and maximum data throughput rate of 70 MSPS per stop input are possible.

AS6501 Time-to-Digital Converter

AS6501 features and benefits


  • 2 stop channels with 5 ns / 20 ns pulse-to-pulse spacing
  • Maximum 70 MSPS per LVDS output
  • Single shot accuracy 20 ps RMS resolution per channel, 10 ps RMS with high resolution option
  • Unlimited measuring range 0s to 16s
  • Differential reference clock input 2 MHz to 12.5 MHz, optional with quartz
  • LVDS inputs and outputs, 16-stage FIFO per channel, SPI compatible 4-wire interface for configuration, optionally to be used for data readout
  • Automatic calibration to reference clock
  • Supply voltage 3.3 V
  • Power dissipation up to 450 mW, standby current 60 μA
  • QFP48 package (7 x 7 mm², 9 × 9 mm² with leads)


  • Simple data post-processing thanks to calibrated results
  • Event assignment thanks to reference clock & index simplifies coincidence measurements
  • Easy pulse width measurements
  • High efficiency due to high sample rate
  • Compact design thanks to small package and low number of external components
  • Reduced cooling because of low power consumption

Product properties

  • Channels 2
  • Inputs LVDS / CMOS
  • Resolution [ps] 10
  • Pulse-Pair Resolution [ns] 5
  • Measurement Rate [MSPS] 70
  • Multi-Hit Capability Unlimited
  • Operating Supply Range [V] 2.4 to 3.6
  • Interface LVDS / SPI
  • Ambient Temperature Range [°C] -40 to 125
  • Package QFP48


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Related Tools

Development kit

The AS6501 development kit allows customers a quick and intuitive approach to using the AS6501 2-channel time-to-digital converter.