841S012DI Datasheet

©2016 Integrated Device Technology, Inc

January 4, 2016

18

3. Calculations and Equations.

The purpose of this section is to calculate power dissipation on the IC per HCSL output pair.

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

HCSL is a current steering output which sources a maximum of 17mA of current per output. To calculate worst case on-chip power

dissipation, use the following equations which assume a 50

Ω load to ground.

The highest power dissipation occurs at maximum V

DD

.

Power

= (V

DD_MAX

– V

OUT ) * IOUT,

since V

OUT = IOUT * RL

= (V

DD_MAX

– I

OUT * RL) * IOUT

= (3.465V – 17mA * 50

Ω) * 17mA

Total Power Dissipation per output pair = 44.5mW

FIGURE 8. HCSL DRIVER CIRCUIT AND TERMINATION

VDD

VOUT

RL

50



IC

IOUT = 17mA

RREF =

475

 ± 1%