BU2374FV Datasheet, PDF (7/8 Pages) Rohm – VCO + phase comparator IC for PLL system

Multimedia ICs
!Application example
LOGIC VDD
1 LOGIC VDD
H:VCO_OUT 1/4 divide
L :VCO_OUT normal
2 SELECT
Bypass
capacitor
Ref input
3 VCO OUT
4 FIN-A
1/N
5 FIN-B
LOGIC GND
6 PFD OUT
7 LOGIC GND
BU2374FV
VCO VDD 14
BIAS 13
VCO IN 12
VCO GND 11
VCO VDD
R
Bypass
capacitor
R
R
VCO GND
VCO INHIBIT 10
PFD INHIBIT 9
H:VCO out Disable
L:VCO out Enable
H:PFD out Disable
L:PFD out Enable
TEST 8
VCO_VDD,VCO_GND
Please take care this Power line. Because this line is most weak in digital noise.
So this line must be separated from LOGIC_VDD, GND.
And place bypass capacitor (0.1µF) for power pin as close to BU2374FV as possible.
LOGIC_VDD, LOGIC_GND
This line is noise source. So it should be separated from AVDD (AGND).
And place bypass capacitor (0.1µF) for power pin as close to BU2374FV as possible.
And this line should be connected VDD of external voc-out divide.
Bias
Please take care because the bias is weak in digital noise.
And place capacitor (0.1µF) close to BU2374FV.
∗Recommend to use capacitor that is better to reduce high frequency noise.
∗Recommend to control (SELECT, PFD_INHIBIT, VCO_INHIBIT) by power line (LOGIC_VDD, LOGIC_GND).
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