ics8535-21 Integrated Device Technology, ics8535-21 Datasheet - Page 11

• Manufacturer Part Number: ics8535-21
• Description: Low Skew, 1-to-2 Lvcmos/lvttl-to-3.3v Lvpecl Fanout Buffer
• Manufacturer: Integrated Device Technology

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 4.
Figure 4. 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™ 3.3V 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
ICS8535-21
LOW SKEW, 1-TO-2 LVCMOS/LVTTL-TO-3.3V LVPECL FANOUT BUFFER
CC
•
•
– 2V.
For logic high, V
(V
For logic low, V
(V
OL_MAX –
OH_MAX –
CC_MAX
CC_MAX
– V
– V
(V
(V
CC_MAX
OH_MAX
OL_MAX
CC_MAX
OUT
V
OUT
CC
Q1
= V
= V
) = 1.7V
) = 0.9V
– 2V))/R
– 2V))/R
OL_MAX
OH_MAX
L
] * (V
L
] * (V
= V
= V
CO_MAX
CC_MAX
CC_MAX
CC_MAX
RL
50Ω
V
CC
-
2V
V
– 1.7V
OUT
– V
– 0.9V
– V
OL_MAX
OH_MAX
) = [(2V – (V
) = [(2V - (V
11
CC_MAX
CC_MAX
– V
– V
OL_MAX
OH_MAX
))/R
))/R
ICS8535AG-21 REV. A FEBRUARY 24, 2009
L
] * (V
L
] * (V
CC_MAX
CC_MAX
– V
– V
OL_MAX
OH_MAX
) =
) =