Charge Pump And Loop Filter - Altera Cyclone IV Device Handbook

5–38
Figure 5–25
PLLs of Cyclone IV devices.
Figure 5–25. Scan Chain Bit Order
HB HB
0 1
LB LB
DATAOUT
0 1

Charge Pump and Loop Filter

You can reconfigure the charge pump and loop filter settings to update the PLL
bandwidth in real time.
charge pump current (I
Cyclone IV devices.
Table 5–8. Charge Pump Bit Control
Table 5–9. Loop Filter Resistor Value Control
Cyclone IV Device Handbook,
Volume 1
shows the scan chain bit order sequence for one PLL post-scale counter in
HB HB HB
2 3 4
LB LB
LB
2
3 4
Table 5–8
), loop filter resistor (R), and capacitor (C) values for PLLs of
CP
CP[2]
0
1
1
1
LFR[4] LFR[3]
0 0
0 0
0 0
0 1
1 0
1 0
1 0
1 1
1 1
1 1
1 1
Chapter 5: Clock Networks and PLLs in Cyclone IV Devices
HB HB HB
HB
8
5 6
7
LB
LB LB
LB
5
6 7
8
through Table 5–10 list the possible settings for
CP[1] CP[0]
0 0
0 0
1 0
1 1
LFR[2] LFR[1]
0 0
0 1
1 0
0 0
0 0
0 1
1 0
0 0
0 1
1 0
1 1
PLL Reconfiguration
HB
DATAIN
rbypass
9
LB
rselodd
9
Setting (Decimal)
0
1
3
7
Setting
LFR[0]
(Decimal)
0 0
1 3
0 4
0 8
0 16
1 19
0 20
0 24
1 27
0 28
0 30
October 2012 Altera Corporation