ICS8741004_1 Datasheet, PDF (15/19 Pages) Integrated Device Technology – DIFFERENTIAL-TO-LVDS/0.7V DIFFERENTIAL PCI EXPRESS™ JITTER ATTENUATOR

ICS8741004
DIFFERENTIAL-TO-LVDS/0.7V DIFFERENTIAL PCI EXPRESS™ JITTER ATTENUATOR
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 6.
V DD O
VOU T
RL
50
IC
Figure 6. HCSL Driver Circuit and Termination
To calculate worst case power dissipation into the load, use the following equations which assume a 50Ω load and a termination
voltage of V_DDO – 2V.
Pd_H is power dissipation when the output drives high.
Pd_L is the power dissipation when the output drives low.
Pd_H = (V_{OH_MAX} /R_L) * (V_{DDO_MAX} – V_{OH_MAX})
Pd_L = (V_{OL_MIN} /R_L) * (V_{DDO_MAX} – V_{OL_MIN})
Pd_H = (0.85V /50Ω) * (3.465V – 0.87V) = 44.1mW
Pd_L = (0.15V/50Ω) * 0.15V = 0.45mW
Total Power Dissipation per output pair = Pd_H + Pd_L = 45mW
IDT™ / ICS™ PCI EXPRESS™ JITTER ATTENUATOR
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ICS8741004AG REV. ANOVEMBER 1, 2007