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5
FS781BZB (DIGITAL VIDEO ASSY: IC1802)
Low EMI Clock IC
Pin Assignment (Top View)
Xin
1
Xout
2
FS78x
S1
3
LF
4
8 Pin SOIC Package
Block Diagram
250 K
Xin
1(3)
8 pF
Xout
2(4)
Power Contol
VDD
8(2)
Logic
Pin Function
No.
Pin Name
I/O
1/2 Xin/Xout
I/O
7/3 S0/S1
I
CMOS/TTL
4
LF
I
6
FSOUT
O
CMOS/TTL
8
VDD
P
5
VSS
P
5
6
8
VDD
7
S0
6
FSOUT
5
VSS
Reference
Divider
Modulation
Control
8 pF
VDD
Input Control Logic
5(7)
3(5)
7(1)
VSS
S1
S0
Type
Pins form an on-chip reference oscillator when connected to terminals of an external parallel
Analog
resonant crystal. Xin may be connected to TTL/CMOS external clock source. If Xin connected to
external clock other than crystal, leave Xout (pin2) unconnected.
Digital control inputs to select input frequency range and output frequency scaling. Refer to
Tables 7 and 8 for selection. S0 has internal pulldown. S1 has internal pullup.
Loop Filter. Single ended tri-state output of the phase detector. A two-pole passive loop filter is
Analog
connected to Loop Filter (LF).
Modulated Clock Frequency Output. The center frequency is the same as the input reference
frequency for FS781. Input frequency is multipled by 2X and 4X for FS782 and FS784
respectively.
Power
Positive Power Supply
Power
Power Supply Ground
6
7
Loop Filter
4(6)
Phase
Detector
VCO
10 pF.
VCO / N
Output
Divider
and
Mux
VSS
(TSSOP Pin #)
Function
PDP-503PC
7
8
FSOUT
6(8)
105
8
A
B
C
D
E
F
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