VSC830 datasheet(14/18 Pages) VITESSE

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VITESSE

SEMICONDUCTOR CORPORATION

Data Sheet

VSC830

Dual 2x2 Crosspoint Switch

2.7Gb/s Asynchronous

G52192-0, Rev 4.0

Page 14

05/23/01

Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com

Internet: www.vitesse.com

Figure 7: Examples of High-Speed Output I/O Termination for VSC830

Power Supply and Layout Considerations

The VSC830 is a single supply part, requiring only a 3.3V supply. The location and hook-up of the bypass

capacitors is critical to providing the VSC830 with a clean 3.3V power supply. VCC that are adjacent can share

a 0.027

µF capacitor connected to V

EE.

Normally the four channel specific VCC pins (VCCP1A, VCCP1B, VCCP2A, VCCP2B) are connected to one

common VCC plane. In the same way the four channel specific VEE pins are connected to the common VEE

plane. A suggested decoupling schematic for this configuration is shown in Figure 7a. However, a slightly

higher signal integrity can be achieved if these pins are treated as different power supplies. In this case,

VCCP1A should then be decoupled to VEE1A etc, as shown in Figure 7b.

VCC

Ω

100Ω

0.1µF

ZO = 50Ω

VCC

Ω

50Ω

0.1µF

50Ω

VCC

ZO = 50Ω

a) Single-Ended AC Termination (Receiver internal biasing required)

b) DC Termination

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