PXB4220EV3.4X Infineon Technologies, PXB4220EV3.4X Datasheet - Page 76

• Manufacturer Part Number: PXB4220EV3.4X
• Manufacturer: Infineon Technologies

Specifications of PXB4220EV3.4X

• Data Rate: 2.048Mbps
• Number Of Channels: 1
• Operating Supply Voltage (typ): 3.3V
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Compliant

Figure 20
The tuning range of the DCO is limited to the value programmed to bits “tur” in register
“condN”. If the phase detector requests a higher frequency deviation the DCO enters
out-of-range condition. In this case the DCO’s output will be clipped and bit “max” of
register “statN” will be set. If the number of out-of-range conditions during 16 ATM cells
exceeds the value given by field “tr_acm” of register “treshN”, an out-of-lock message,
indicated via field “ola” of register “oolN”, is generated.
Increasing the loop-gain reduces the damping of the PLL-ACM. This will reduce the rise
time but results in overshoot and long lock-in times.
Reducing the loop-gain increases the damping. This results in lower cut off frequencies,
and prevents overshoot. Thus, CDV is less likely to drive the PLL out of lock. The rise
and lock-in time are increased. If the loop-gain is too low, the amount of bytes required
to drive the DCO over it's tuning range could cause a data buffer over- or underflow.
Optimized damping allows minimum lock-in time without overshoot. In this case PLL-
ACM’s frequency is moving asymptotically to the correct value.
Data Sheet
0.1
0.9
f/f
1
0
Transient Parameters
2d
Tr1
Tr
Mp
Tp
76
PXB 4219E, PXB 4220E, PXB 4221E
Tl
Tr, Tr1: Rise time
Tp:
Tl:
Mp:
2d:
f
0
:
Operational Description
Peak time
Lock in time
Peak overshoot
Tuning range
Target frequency
ACM Transient Parameters
IWE8, V3.4
2003-01-20
t