TDC-GP2 acam messelectronic gmbh, TDC-GP2 Datasheet - Page 22

• Manufacturer Part Number: TDC-GP2
• Description: Precision Time Interval Measurement
• Manufacturer: acam messelectronic gmbh

Figure 10
R u n tim e
H ig h -s p e e d u n it
clo ck
S ta r t
S to p
R e f.
4 Measurement Range 2
Digital TDCs use internal propagation delays of signals
through gates to measure time intervals with very
high precision (see also measurement range 1, sec-
tion 4).
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 3.3 V and 25 °C
ambient temperature. The RMS Noise is approx. 50 ps
(0.7 LSB). 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 measurement range is limited by size of the coarse
counter:
t
The time interval between START and STOP is
calculated with a 26 Bit measurement range.
yy
= T
1 stop channels referring to one start channel
Typ. 50 ps RMS resolution
LSB width typ. 65 ps
2 x Tref pulse pair resolution
3-fold multihit capability
Measurement range 2 x Tref to 4 ms @ 4MHz
Selectable rising/falling edge sensitivity
Integrated programmable windowing for each single
stop with 10 ns precision
ref
F in e c o u n t 1
x 2
acam-messelectronic gmbh - Am Hasenbiel 27 - D-76297 Stutensee-Blankenloch - Germany - www.acam.de
1 4
tim e = T re f x ( C c + (F c 1 - F c2 )/ (C a l2 - C a l1 )
4 ms @ 4MHz
C o a rs e co un t
F in e c o u n t 2
C a l1
C a l2
22
t
t
t
t
t
t
t
ph
pl
ss
r r
ff
va
yy
Input circuitry
Each input separately can be set to be sensitive to
rising or falling edge. This is done in register 0, Bits 0
to 2. (NEG_START, NEG_STOP1).
Further all Start/Stop-inputs support a high active
enable pin.
Note:
In case the Start-Stop interval is less than the lower
limit t
smaller it is. In no case there will be wrong results.
Stop 1
Time (Condition)
2,5 ns (min.)
2,5 ns (min.)
2*Tref
2*Tref
2*Tref
4.6 µs (max.)
4 ms (max)
Start
INTN
zz
the TDC will ignore more and more events the
t
ph
t
ss
Description
Minimum pulse width
Minimum pulse width
Start to Stop @ Dis_Phasenoise=1
Rising edge to rising edge
Falling edge to falling edge
ALU start to data valid
Max. measuring range
t
ph
Figure 11
t
t
rr
yy
t
pl
t
ff
TDC-GP2
t
va