ICS8525 View Datasheet(PDF) - Integrated Circuit Systems

Part Name

Description

MFG CO.

ICS8525

LOW SKEW, 1-TO-4 LVCMOS-TO-LVHSTL FANOUT BUFFER

Integrated Circuit Systems 

Integrated

Circuit

Systems, Inc.

ICS8525

LOW SKEW, 1-TO-4

LVCMOS-TO-LVHSTL FANOUT BUFFER

3. Calculations and Equations.

The purpose of this section is to derive the power dissipated into the load.

LVHSTL output driver circuit and termination are shown in Figure 8.

VDDO

Q1

VOUT

RL

50

VDDO - 2V

FIGURE 8 - LVHSTL 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.

DD

Pd_H is power dissipation when the output drives high.

Pd_L is the power dissipation when the output drives low.

Pd_H = (V

/R ) * (V

-V

)

OH_MAX L

DD_MAX OH_MAX

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

OL_MAX L

DD_MAX OL_MAX

• For logic high, V = V

=V

– 1.2V

OUT

OH_MAX

DD_MAX

• For logic low, V = V

=V

– 0.4V

OUT

OL_MAX

DD_MAX

Pd_H = (1.2V/50Ω) * (2V - 1.2V) = 19.2mW

Pd_L = (0.4V/50Ω) * (2V - 0.4V) = 12.8mW

Total Power Dissipation per output pair = Pd_H + Pd_L = 32mW

8525BG

www.icst.com/products/hiperclocks.html

9

REV. B JULY 27, 2001

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