ICS853001AGLFT View Datasheet(PDF) - Integrated Circuit Systems

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ICS853001AGLFT

1:1, DIFFERENTIAL LVPECL-TO-2.5V, 3.3V, 5V LVPECL/ECL BUFFER

Integrated Circuit Systems 

Integrated

Circuit

Systems, Inc.

ICS853001

1:1, DIFFERENTIAL LVPECL-TO-

2.5V, 3.3V, 5V LVPECL/ECL 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 7.

VCC

Q1

VOUT

RL

50

VCC - 2V

FIGURE 7. 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.

CC

• For logic high, V = V

=V

– 1.005V

OUT

OH_MAX

CC_MAX

(V

- V ) = 1.005

CC_MAX OH_MAX

• For logic low, V = V

=V

– 1.78V

OUT

OL_MAX

CC_MAX

(V

- V ) = 1.78V

CC_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

CC_MAX

L

CC_MAX OH_MAX

CC_MAX OH_MAX

L

CC_MAX OH_MAX

[(2V - 1.005V)/50Ω] * 1.005V = 20mW

Pd_L = [(V – (V - 2V))/R ] * (V

- V ) = [(2V - (V

- V ))/R ] * (V - V ) =

OL_MAX

CC_MAX

L

CC_MAX OL_MAX

CC_MAX OL_MAX

L

CC_MAX OL_MAX

[(2V - 1.78V)/50Ω] * 1.78V = 7.83mW

Total Power Dissipation per output pair = Pd_H + Pd_L = 27.83mW

853001AG

www.icst.com/products/hiperclocks.html

13

REV. A JANUARY 29, 2005

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