LUCW3000CCN AGERE [Agere Systems], LUCW3000CCN Datasheet - Page 21

• Manufacturer Part Number: LUCW3000CCN
• Description: W3000 PLL Dual-Band Frequency Synthesizer
• Manufacturer: AGERE [Agere Systems]

Advance Data Sheet
December 1999
Application Information
For example, take a GSM application where a loop bandwidth of 22 kHz is required.
Other parameters specified by the system are listed below:
Using the formulas above, the three time constants can be calculated as follows:
From these values, we can derive the initial component values as follows:
If we choose R2 = 15 k , then
From these initial values, the loop filter components used in the application circuit can be derived through
practical optimization.
VCO Gain (K
Charge Pump Current (I
Divider Ratio (value of midband frequency used) (N)
Required Phase Margin
Reference Frequency Attenuation from Additional Pole
Lucent Technologies Inc.
T1 = 2.63697E – 10
T2 = 3.14484E – 10
T3 = 2.38732E – 10
R1 = 2992
C1 = 0.96 nF
C2 = 10.5 nF
C3 = 159 pF
VCO)
Parameter
CP)
–6
–5
–6
s
s
s
(continued)
W3000 PLL Dual-Band Frequency Synthesizer
88 MHz/V
2.5 mA
Value
20 dB
7850
45°
21