op183gbc Analog Devices, Inc., op183gbc Datasheet - Page 15

• Manufacturer Part Number: op183gbc
• Description: 5 Mhz Single-supply Operational Amplifiers
• Manufacturer: Analog Devices, Inc.

LOW VOLTAGE FREQUENCY SYNTHESIZER FOR
WIRELESS TRANSCEIVER
The low noise and low voltage operation capability of the
OP183 serves well for the loop filter of a frequency synthesizer.
Figure 39 shows a typical application in a radio transceiver. The
phase noise performance of the synthesizer depends on low
noise contribution from each component in the loop as the
noise is amplified by the frequency division factor of the
prescaler.
The resistors used in the low-pass filter should be of low to
moderate values to reduce noise contribution due to the input
bias current as well as the resistors themselves. The filter cutoff
frequency should be chosen to optimize the loop constant.
B
RB2
QB4
QB2
A
RB1
QB5A
QB3
QB1
JB1
R3LT
CB1
R10
QB9
1
RB3
2
R3AT
Q1
R3A
R3B
R1
Z1
CC1
Figure 40. OP183 Simplified Schematic
R4A
R4B
QB10
R2
R4AT
Q2
R4LT
Rev. D | Page 15 of 16
R11
3
5
QB6
RB4
QB12
Q3
OSCILLATOR
REFERENCE
Figure 39. Low Voltage Frequency Synthesizer for a Wireless Transceiver
QB7
CRYSTAL
RB5
QD1
Q7
Q5
QB13
DETECTOR
Q4
QB8
PHASE
CF1
RB6
PRESCALER
Q8
QB14
Q6
÷
R5
CC3
Q10
RF
OUT
QB11
QD2
R9
QD3
V
CO
R7
CC2
CONTROL
R8
900MHz
VCO
7
4
Q12
Q11
OP183
3V
6
OP183