lc72133m Sanyo Semiconductor Corporation, lc72133m Datasheet - Page 16

• Manufacturer Part Number: lc72133m
• Description: Pll Frequency Synthesizer For Electronic Tuning
• Manufacturer: Sanyo Semiconductor Corporation

IF Counter Structure
The LC72133 IF counter is a 20-bit binary counter. The result, i.e., the counter’s MSB, can be read serially from the DO
pin.
The IF frequency (Fc) is measured by determining how many pulses were input to an IF counter in a specified
measurement period, GT.
Fc =
1. IF Counter Frequency Calculation Examples
GT1
0
0
1
1
• When the measurement period (GT) is 32 ms, the count (C) is 53980 hexadecimal (342400 decimal):
• When the measurement period (GT) is 8 ms, the count (C) is E10 hexadecimal (3600 decimal):
GT
IF frequency (Fc) = 342400 32 ms = 10.7 MHz
IF frequency (Fc) = 3600 8 ms = 450 kHz
C
GT0
0
1
0
1
IFIN
Measurement period (GT) (ms)
(C = Fc GT)
32
64
4
8
Measurement time
0
0
GT0
4/8/32/64
0
1
ms
0
5
0
0
GT1
0
1
(Fc)
0
0
Wait time (twu) (ms)
LC72133M, 72133V
C: Count value (number of pulses)
0
0
(GT)
0
3
1
0
3 to 4
3 to 4
7 to 8
7 to 8
0
1
1
1
L
S
B
C = Fc
0 to 3
1
0
E
9
0
1
0
1
4 to 7 8 to 11 12 to 15 16 to 19
GT
(20-bit binary counter)
1
0
CTE
0
0
IF counter
8
1
0
0
1
0
0
0
0
0
0
0
0
0
0
0
M
S
B
(C)
DO pin
A11934
A11933
A11932
No. 5427-16/23