• 1 stop channel referring to one start channel
• Typ. 65 ps resolution
• 2xTref pulse pair resolution
• 3-fold multihit capability
• Measurement range 500 ns to 4 ms
• Selectable rising/falling edge sensitivity
• Powerful windowing functionality

Digital TDCs use internal propagation delays of signals through gates to measure time intervals with very high precision (see also measurement range 1).
In measurement range 2 the maximum time interval is extended using a pre-divider. The resolution in LSB remains unchanged by that. In this mode the high-speed unit of the TDC does not measure the whole time interval but only time intervals from START and STOP to the next rising edge of the reference clock (fine-counts). In between the fine-counts the TDC counts the number of periods of the reference clock (coarse-count).

The BIN size (LSB) is typically 65 ps at 3.6 V and 25 °C ambient temperature. The gate propagation delay times strongly depend on temperature and voltage. In measuring range 2 the result is the sum of different fine and coarse-count results. Therefore it is necessary in measuring range 2 to make a calibration. During a calibration the TDC measures 1 and 2 periods of the reference clock.

The measuring unit is actuated by a START signal and stopped by a STOP signal. Based on the position of the ring oscillator and the coarse counter the time interval between START and STOP is calculated with a 26 Bit measurement range.

The measurement range is limited by size of the coarse counter:
tyy = Tref x 16384 ~ 4 ms

	Time (Condition)	Description
tph	2.5 ns	Minimum pulse width
tpl	2.5 ns	Minimum pulse width
tss	500 ns min.	Start to Stop
trr	ns	Rising edge to rising edge
tff	ns	Falling edge to falling edge
tva	4.6 µs calibrated	Last hit to data valid
tyy	4 ms	Measurement range