BU2373FV_11 Datasheet, PDF (11/19 Pages) Rohm – High Performance VCOs for Image Sampling

BU2373FV,BU2374FV
Technical Note
●Description of operations
VCO Block
Our VCO block consists of ring oscillators using 5-step reverse Amp. Setting the 2PIN: SELECT to “H” makes it possible to
set the system to output frequency dividing mode. (The frequency is divided to 1/2 on the BU2373FV, while 1/4 on the
BU2374FV.) 50% of the frequency is guaranteed even to the duty at this time.
Furthermore, setting the 10Pin: VCO_INHIBIT to “H” makes it possible to set the system to power-down mode. While in
power-down mode, the VCO_OUT output is fixed to “L”, thus achieving reduction in Analog consumption current
approximately by 80%.
In addition, through the adjustment of external resistance value for the BIAS terminal on 13Pin, the fine adjustment of
output frequency can be made.
(VCO I/O Characteristics)
frequency
(MHz)
It is possible to adjust
center frequency with bias -
res is tor
0
Fig.52
VCO_IN (V)
* The VCO built in the BU2373FV has been designed to provide the lowest frequency sensitivity when using the VCO_IN
at about VDD/2. To make use of the VCO, it is recommended to adjust the BIAS resistance so that the voltage of the
VCO_IN will reach VDD/2.
(Configuration of VCO Block)
VCOIN
Bias
block
VCO_INHIBIT
Level
Shifter
L
1/2
1/2
H
SELECT
Fig.53
VCO_OUT
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11/18
2011.08 - Rev.B