843404AG

www.icst.com/products/hiperclocks.html

REV. A OCTOBER 17, 2005

13

Integrated

Circuit

Systems, Inc.

ICS843404

LVCMOS/CRYSTAL-TO-3.3V LVPECL AND

LVDS CLOCK GENERATOR

TERMINATION FOR 2.5V LVPECL OUTPUT

Figure 5A and Figure 5B show examples of termination for 2.5V

LVPECL driver. These terminations are equivalent to terminat-

ing 50

Ω to V

DD - 2V. For VDDO = 2.5V, the VDDO - 2V is very close to

ground level. The R3 in Figure 5B can be eliminated and the

termination is shown in Figure 5C.

FIGURE 5C. 2.5V LVPECL TERMINATION EXAMPLE

FIGURE 5B. 2.5V LVPECL DRIVER TERMINATION EXAMPLE

FIGURE 5A. 2.5V LVPECL DRIVER TERMINATION EXAMPLE

R2

62.5

R3

250

2.5V

VDDO=2.5V

Zo = 50 Ohm

R1

250

+

-

2,5V LVPECL

Driv er

R4

62.5

2.5V

Zo = 50 Ohm

Zo = 50 Ohm

+

-

VDDO=2.5V

R2

50

R1

50

2,5V LVPECL

Driv er

2.5V

R3

18

Zo = 50 Ohm

Zo = 50 Ohm

R1

50

VDDO=2.5V

2.5V

R2

50

2,5V LVPECL

Driv er

Zo = 50 Ohm

+

-

ICS843404

LVCMOS/CRYSTAL-TO-3.3V LVPECL AND LVDS CLOCK GENERATOR

TSD

IDT™ / ICS™ LVCMOS/CRYSTAL-TO-3.3V LVPECL AND LVDS CLOCK GENERATOR

ICS843404

13