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S/UNI-QUAD
PMC-Sierra, Inc.
PM5349 S/UNI-QUAD
DATASHEET
PMC-971239 ISSUE 6 SATURN USER NETWORK INTERFACE (155-QUAD)
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
221
The RXD+/- inputs to the S/UNI-QUAD are DC coupled as shown. The device
has a true PECL receiver so only termination resistors are required.
Ceramic coupling capacitors are recommended.
Figure 21: Interfacing to ECL or PECL
Zo
S/UNI-QUAD
Optics
PMD
Zo
Zo
Zo
2*Zo
RxD+
RxD-
Gnd
Gnd
Rd
Rd
RD+
RD-
0.1 uF
0.1uF
TxD+
TxD-
RS1
VDD
Gnd
Zo
Zo
R1
R2
TD+
TD-
SD
SD
0.01uF or
0.1 uF
Vpp = (Zo/((RS1+Rs)+Z0) * Vdd
- Vdd (S/UNI-QUAD’s analog transmit power) 3.3V
- Zo (trace impedance) typically 50
Ω
- Rs (TxD source impedance) typically 15-20
Ω
-
RS1 : ~ 158
Ω
Notes: Vpp is minimum input swing required by the optical PMD device.
Vbb is the switching threshold of the PMD device (typically Vdd - 1.3 volts)
Vpp is Voh - Vol (typically 800 mVolts)
Vdd * R2/(R1+R2) = Vbb
RS1
Gnd
Rd
VDD
For interfacing to 5.0V ODL, R1 : 237
Ω
, R2 : 698
Ω
Rd : 330
Ω
For interfacing to 3.3V ODL, R1 : 220
Ω
, R2: 330
Ω
Rd : 150
Ω