U2781B Datasheet, PDF (6/10 Pages) TEMIC Semiconductors – Frequency Synthesizer

U2781B
Pulse Diagram Phase and Lock Detector
fp (fvco/Tp)
fr (fosc/Tp)
Vcp
LD
93 7786 e
Figure 4.
The LD output is in unlocked condition at low level and the pulsewidth is in reference to the phase respectively fre-
quency difference at the phase detector. If the phase detector output pulses are smaller than 100 ns, the LD output goes
high and indicates “lock” condition.
Test Circuit
Input sensitivity
Frequency
Counter
10 k
Monitor
U2781B
V_S = 3 V
1m
10 n
1n
94 8904
Figure 5.
Enable
Data
Clock
RF Test
Generator
6 (10)
TELEFUNKEN Semiconductors
Rev. A3, 26-Nov-97