ics8430ay62l Integrated Device Technology, ics8430ay62l Datasheet - Page 18

• Manufacturer Part Number: ics8430ay62l
• Description: Ics8430-62 500mhz, Crystal-to-3.3v, 2.5v Differential Lvpecl Frequency Synthesizer
• Manufacturer: Integrated Device Technology

ICS8430-62 Datasheet
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 8.
Figure 8. LVPECL Driver Circuit and Termination
T
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
ICS8430AY-62 REVISION A JULY 2, 2009
o calculate worst case power dissipation into the load, use the following equations which assume a 50Ω load, and a termination voltage of
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
CC
) = 1.7V
) = 0.9V
OL_MAX
– 2V))/R
– 2V))/R
OH_MAX
= V
L
= V
L
] * (V
] * (V
CCO_MAX
CCO_MAX
CCO_MAX
CCO_MAX
RL
50Ω
V
CC
– 1.7V
-
– 0.9V
2V
V
– V
OUT
– V
OL_MAX
OH_MAX
) = [(2V – (V
) = [(2V – (V
18
500MHz CRYSTAL-TO-3.3V, 2.5V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER
CCO_MAX
CCO_MAX
– V
– V
OL_MAX
OH_MAX
))/R
))/R
L]
L
* (V
] * (V
CCO_MAX
©2009 Integrated Device Technology, Inc.
CCO_MAX
– V
– V
OL_MAX
OH_MAX
) =
) =