si5540 Silicon Laboratories, si5540 Datasheet - Page 11

• Manufacturer Part Number: si5540
• Description: Siphy Oc-192/stm-64 Transmitter - Silicon Laboratories
• Manufacturer: Silicon Laboratories

Differential Output Circuitry
The Si5540 utilizes a current-mode logic (CML) architecture to drive the high speed serial output clock and data on
TXCLKOUT and TXDOUT. An example of output termination with ac coupling is shown in Figure 4. In applications
where direct dc coupling is possible, the 250 nF capacitors may be omitted. The differential peak-to-peak voltage
swing of the CML architecture is listed in Table 2 on page 5.
Figure 4. CML Output Driver Termination (TXCLKOUT, TXDOUT)
50
1.5 V
24 mA
50
Preliminary Rev. 0.31
250 nF
250 nF
Zo = 50
Zo = 50
VDD
VDD
50
50
Si5540
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