ICS8531-01 View Datasheet(PDF) - Integrated Device Technology
Part Name
Description
MFG CO.
'ICS8531-01' PDF : 18 Pages View PDF
ICS8531-01
LOW SKEW, 1-TO-9, DIFFERENTIAL-TO-3.3V LVPECL FANOUT BUFFER
3. Calculations and Equations.
The purpose of this section is to derive the power dissipated into the load.
LVPECL output driver circuit and termination are shown in Figure 6.
VCCO
Q1
VOUT
RL
50
V - 2V
CCO
FIGURE 6. LVPECL 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 - 2V.
CCO
• For logic high, V = V = V
– 0.9V
OUT
OH_MAX
CCO_MAX
(V - V ) = 0.9V
CCO_MAX
OH_MAX
• For logic low, V = V = V – 1.7V
OUT
OL_MAX
CCO_MAX
(V - V ) = 1.7V
CCO_MAX
OL_MAX
Pd_H is power dissipation when the output drives high.
Pd_L is the power dissipation when the output drives low.
Pd_H = [(V – (V - 2V))/R ] * (V - V ) = [(2V - (V
- V ))/R ] * (V - V ) =
OH_MAX
CCO_MAX
L
CCO_MAX
OH_MAX
CCO_MAX
OH_MAX
L
CCO_MAX
OH_MAX
[(2V - 0.9V)/50Ω] * 0.9V = 19.8mW
Pd_L = [(V – (V - 2V))/R ] * (V - V ) = [(2V - (V
- V ))/R ] * (V - V ) =
OL_MAX
CCO_MAX
L
CCO_MAX
OL_MAX
CCO_MAX
OL_MAX
L
CCO_MAX
OL_MAX
[(2V - 1.7V)/50Ω] * 1.7V = 10.2mW
Total Power Dissipation per output pair = Pd_H + Pd_L = 30mW
IDT™ / ICS™ 1-TO-9, 3.3V LVPECL FANOUT BUFFER
13
ICS8531AY-01 REV. F APRIL 11, 2007
Share Link: 
