SM5160CM Datasheet, PDF (5/7 Pages) Nippon Precision Circuits Inc – Programable PLL Frequency Synthesizer

SM5160CM/DM
FUNCTIONAL DESCRIPTION
Lowpass Filter Connection
An external lowpass filter connects to DOP or DOA.
The output form the filter is fed to a voltage-controlled
oscillator (VCO) which generates the PLL output.
DOP is intended for use with a passive filter as shown
in figure 1. DOA is intended for use with an active filter
as shown in figure 2.
DOP
R1
VCO
R2
C
Programmable Frequency Divider
The input frequency divider and reference frequency
divider ratios can be programmed using the serial data
input.
Input data consists of 16 data bits, in the order msb to
lsb, followed by a control bit, as shown in figure 3 and 4.
SM5160CM
If the control bit is set to 0, the data is written to the
16-bit latch and then passed to the input frequency
divider.
If the control bit is set to 1, the 2 lsbs are ignored and
the remaining data is written to the 14-bit latch and then
passed to the reference frequency divider.
Figure 1. Passive lowpass filter circuit
R1
DOA
VDD VDD
R2 C RL
VCO
510kΩ
Figure 2. Active lowpass filter circuit
16BIT (N- COUNTER DATA)
ignored
14BIT (R- COUNTER DATA)
1: R-LATCH 0: N-LATCH
Figure 3. Serial data format (SM5160CM)
SM5160DM
If the control bit is set to 0, the data is written to the
16-bit latch and then passed to the input frequency
divider.
If the control bit is set to 1, the 2 lsbs and 3msbs are
ignored and the remaining data is written to the 11-bit
latch and then passed to the reference frequency divider.
16BIT (N- COUNTER DATA)
ignored
11BIT (R- COUNTER DATA)
ignored
1: R-LATCH 0: N-LATCH
Figure 4. Serial data format (SM5160DM)
NIPPON PRECISION CIRCUITS-5