8413S12I-100 Datasheet, PDF (25/33 Pages) Integrated Device Technology – Ten 100MHz clocks for PCI Express

3. Calculations and Equations.
The purpose of this section is to calculate power dissipation on the IC per HCSL output pair.
HCSL output driver circuit and termination are shown in Figure 7.
VDDO
I_OUT = 17mA
8413S12I-100 DATA SHEET
R_REF =
475Ω ± 1%
V_OUT
R_L
50Ω
IC
Figure 7. HCSL Driver Circuit and Termination
HCSL is a current steering output which sources a maximum of 17mA of current per output. To calculate worst case on-chip power dissipation,
use the following equations which assume a 50 load to ground.
The highest power dissipation occurs when V_DD__MAX.
Power = (V_{DD_MAX} – V_OUT) * I_OUT
since V_OUT = I_OUT * R_L
Power = (V_{DD_MAX} – I_OUT * R_L) * I_OUT
= (3.465V – 17mA * 50) * 17mA
Total Power Dissipation per output pair = 44.5mW
REVISION B 2/03/2015
25
CLOCK GENERATOR FOR CAVIUM PROCESSORS