AK1548 Datasheet, PDF (26/42 Pages) Asahi Kasei Microsystems – 8GHz Low Noise Integer-N Frequency Synthesizer

[AK1548]
CP2[2:0] : Charge pump current setting 2
CP1[2:0] : Charge pump current setting 1
AK1548 provides two setting for charge pump current. They can be set by {CP1} and {CP2}.
The following formula shows the relationship among the resistance value, the register setting and the
electric current that is used for LPF band calculation (tran_Icp).
tran_Icp [A] = Icp_min [A] × ({CP1} or {CP2} setting +1)
Charge pump minimum current (Icp_min)[A]
= (0.85×1.164×15) / Resistance connected to the BIAS pin [ohm]
The following table shows the typical tran_Icp for each status.
D18 D17 D16
D15 D14 D13
000
001
010
011
100
101
110
111
tran_Icp (typical)
Bias Resistance
33 kΩ
27 kΩ
22 kΩ
450
550
675
900
1100
1350
1350
1650
2025
1800
2200
2700
2250
2750
3375
2700
3300
4050
3150
3850
4725
3600
4400
5400
[Unit : μA]
Remarks
The following formula shows the relationship among the resistance value, the register setting and the
electric current that can be measured (Icp).
Icp [A] = Icp_min [A] × ({CP1} or {CP2} setting +1)
Charge pump minimum current (Icp_min)[A]
= (1.164×15) / Resistance connected to the BIAS pin [ohm]
The following table shows the typical tran_Icp for each status.
MS1364-E-00
26
2012/1