VSC8151 查看數據表（PDF） - Vitesse Semiconductor
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VSC8151 Datasheet PDF : 30 Pages
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VITESSE
SEMICONDUCTOR CORPORATION
Advance Product Information
VSC8151
2.488Gb/s SONET/SDH
STS-48/STM-16 Section Terminator
The serial demux can be bypassed and the 16-bit single-ended PECL bus RXPIN[15:0] can be used to input
SONET/SDH data for applications where the data has already been deserialized by a previous device. This
mode is selected by asserting the EQULOOP input (active high). Input setup and hold requirements are speci-
fied with respect to the falling edge of POUTCLK; the user is responsible for meeting loop timing requirements
between the VSC8151 and previous device. The user must still provide a line rate clock to the serial clock input
RXSLKIN+/- to provide a high-speed output clock to the mux and the means to create the divide-by-16 POUT-
CLK.
2.5G Serial and Parallel Output Interfaces
The high speed clock and data output driver consists of a differential pair designed to drive a 50Ω transmis-
sion line. The transmission line should be terminated with a 100Ω resistor at the load between true and comple-
ment outputs. No connection to a termination voltage is required. The output driver is source terminated to 50Ω
on-chip, providing a snubbing of any reflections. If used single-ended, one way to terminate the output driver is
differentially at the load with a 100Ω resistor between true and complement outputs. See Figure 2A. Another
option is to terminate the used output at the load with 50 ohm to VTERM and the unused output with 50 ohm to
VTERM at the source. See Figure 2B.
In some applications, it may be desirable to turn off the high speed outputs (TXSOUT, TXSCLKOUT) to
reduce power. To disable the high speed clock output, tie pin 22 to VCC (3.3V) instead of GND. To disable the
high speed data output, tie pin 17 to VCC (3.3V) instead of GND. Turning off each output will reduce maximum
current consumption by 107mA for the clock output, and 122mA for the data output.
Figure 2A
Figure 2: High Speed Output Driver & Termination
VCC
50Ω
50Ω
100Ω
Pre-Driver
VEE
Z0 = 50Ω
Figure 2B
VCC
50Ω
50Ω
VTERM
50Ω
Pre-Driver
VEE
50Ω
Z0 = 50Ω
VTERM
G52225-0, Rev. 2.9
12/1/99
© VITESSE SEMICONDUCTOR CORPORATION
741 Calle Plano, Camarillo, CA 93012 • 805/388-3700 • FAX: 805/987-5896
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