ICS85214

LOW SKEW, 1-TO-5, DIFFERENTIAL-TO-HSTL FANOUT BUFFER

IDT™ / ICS™ HSTL FANOUT BUFFER

11

ICS85214AG

REV. B

JUNE 3, 2016

3. Calculations and Equations.

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

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

Figure 6. HSTL Driver Circuit and Termination

To calculate worst case power dissipation into the load, use the following equations which assume a 50 load.

Pd_H is power dissipation when the output drives high.

Pd_L is the power dissipation when the output drives low.

Pd_H = (VOH_MAX /RL) * (VDDO_MAX - VOH_MAX)

Pd_L = (VOL_MAX /RL) * (VDDO_MAX - VOL_MAX)

Pd_H = (1.0V/50

) * (2V - 1.0V) = 20mW

Pd_L = (0.4V/50

) * (2V - 0.4V) = 12.8mW

Total Power Dissipation per output pair = Pd_H + Pd_L = 32.8mW

V

OUT

V

DD

Q1

RL

50

Ω