ICS853017 Datasheet, PDF (12/15 Pages) Integrated Circuit Systems – QUAD, 1-TO-1 DIFFERENTIAL-TO-2.5V/3.3V/5V LVPECL/ECL RECEIVER

ICS853017
QUAD, 1-TO-1, DIFFERENTIAL-TO-2.5V, 3.3V, 5V LVPECL/ECL RECEIVER
3. Calculations and Equations.
LVPECL output driver circuit and termination are shown in Figure 6.
VCC
PRELIMINARY
Q1
VOUT
RL
50
VCC - 2V
FIGURE 6. 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 – 0.935V
OUT
OH_MAX
CC_MAX
(V - V ⁾ = 0.935V
CC_MAX
OH_MAX
• For logic low, V = V = V – 1.67V
OUT
OL_MAX
CC_MAX
(V - V ⁾ = 1.67V
CC_MAX
OL_MAX
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 - 0.935V)/50Ω] * 0.935V = 19.92mW
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 - 1.67V)/50Ω] * 1.67V = 11.02mW
Total Power Dissipation per output pair = Pd_H + Pd_L = 30.94mW
IDT^™ / ICS^™ 2.5V, 3.3V, 5V LVPECL/ECL RECEIVER
12
ICS853017AM REV. B OCTOBER 24, 2007