8538BG-31LF IDT, 8538BG-31LF Datasheet - Page 10

• Manufacturer Part Number: 8538BG-31LF
• Description: Clock Drivers & Distribution
• Manufacturer: IDT

Specifications of 8538BG-31LF

• Product Category: Clock Drivers & Distribution
• Rohs: yes
• Part # Aliases: ICS8538BG-31LF

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 5.
Figure 5. LVPECL Driver Circuit and Termination
T
of V
Pd_H is power dissipation when the output drives high.
Pd_L is the power dissipation when the output drives low.
Pd_H = [(V
[(2V – 0.9V)/50Ω] * 0.9V = 19.8mW
Pd_L = [(V
[(2V – 1.7V)/50Ω] * 1.7V = 10.2mW
Total Power Dissipation per output pair = Pd_H + Pd_L = 30mW
IDT™ / ICS™ LVPECL FANOUT BUFFER
o calculate worst case power dissipation into the load, use the following equations which assume a 50Ω load, and a termination voltage
ICS8538-31
LOW SKEW, 1-TO-8, CRYSTAL OSCILLATOR/LVCMOS-TO-3.3V LVPECL FANOUT BUFFER
CCO
•
•
– 2V.
For logic high, V
(V
For logic low, V
(V
OL_MAX
OH_MAX
CCO_MAX
CCO_MAX
– (V
– (V
– V
– V
CCO_MAX
CCO_MAX
OH_MAX
OUT
OL_MAX
OUT
= V
V
= V
Q1
CCO
) = 1.7V
) = 0.9V
OL_MAX
– 2V))/R
– 2V))/R
OH_MAX
= V
L
L
= V
] * (V
] * (V
CO_MAX
CCO_MAX
CCO_MAX
CCO_MAX
RL
50
V
– 1.7V
CCO
– 0.9V
-
V
2V
– V
OUT
– V
OL_MAX
OH_MAX
) = [(2V – (V
10
) = [(2V – (V
CCO_MAX
CCO_MAX
– V
– V
OL_MAX
OH_MAX
ICS8538BG-31 REV. B FEBRUARY 5, 2008
))/R
))/R
L]
L
] * (V
* (V
CCO_MAX
CCO_MAX
– V
– V
OL_MAX
OH_MAX
) =
) =