AK1573 Datasheet, PDF (24/42 Pages) Asahi Kasei Microsystems – Low Noise Integrated VCO

[AK1573/AK1573B/AK1573C]
The following table shows the typical Icp for each status.
Icp (typ.) unit : μA
CP1[2:0], CP2[2:0]
0
1
2
3
4
5
6
7
33kΩ
286
573
859
1146
1432
1718
2005
2291
BIAS
27kΩ
350
700
1050
1400
1750
2100
2450
2800
22kΩ
430
859
1289
1718
2148
2577
3007
3436
< Address0x03 : Ref/Pres >
D[19:16]
CALTM[3:0] Set the calibration precision of VCO
The register CALTM[3:0] bits set the calibration precision and time. The larger CALTM[3:0] bits
are set, the higher calibration precision becomes, but the longer calibration time is required as
trade-off. Set the value calculated by the following formula to get enough calibration precision.
However, CALTM[3:0] bits should be set from 0 to 10. Over 11 are prohibited. See “15. VCO”
for details of the VCO calibration.
CALTM[3:0] bits ≥ 10 – log (B[12:0] bits) / log(2)
The calibration time can be estimated as following formula;
Calibration time = 1 /F_PFD × 11 × 2 ^ CALTM[3:0] bits
D[15:14]
PRE[1:0] : Selects a dividing ratio for the prescaler
00: P=8
01: P=16
10: P=32
11: P=64
The prescaler value should be selected so that the prescaler output frequency is less
than or equal to 300MHz.
015009351-E-00
- 24 -
2015/8