85314AGI-11

www.icst.com/products/hiperclocks.html

REV. C MAY 24, 2005

13

Integrated

Circuit

Systems, Inc.

ICS85314I-11

3. Calculations and Equations.

LVPECL output driver circuit and termination are shown in Figure 6.

Ω load, and a termination

voltage of V

CC

- 2V.

•

For logic high, V

OUT

= V

OH_MAX

= V

CC_MAX

– 1.0V

(V

CC_MAX

- V

OH_MAX

) = 1.0V

•

For logic low, V

OUT

= V

OL_MAX

= V

CC_MAX

– 1.7V

(V

CC_MAX

- V

OL_MAX

) = 1.7V

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

– (V

CC_MAX

- 2V))/R

L

] * (V

CC_MAX

- V

OH_MAX

) = [(2V - (V

CC_MAX

- V

OH_MAX

))/R

L

] * (V

CC_MAX

- V

OH_MAX

) =

[(2V - 1V)/50

Ω] * 1V = 20.0mW

Pd_L = [(V

OL_MAX

– (V

CC_MAX

- 2V))/R

L

] * (V

CC_MAX

- V

OL_MAX

) = [(2V - (V

CC_MAX

- V

OL_MAX

))/R

L

] * (V

CC_MAX

- V

OL_MAX

) =

[(2V - 1.7V)/50

Ω] * 1.7V = 10.2mW

Total Power Dissipation per output pair = Pd_H + Pd_L = 30.2mW

Q1

V

OUT

V

CC

RL

50

V