PM5380-BI PMC-Sierra, Inc., PM5380-BI Datasheet - Page 408

• Manufacturer Part Number: PM5380-BI
• Description: Network Interface, SATURN User Network Interface (8x155) Telecom Standard Product
• Manufacturer: PMC-Sierra, Inc.

Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC- 2010299, Issue 2
Figure 36 ECL Bias Voltage Generator Networks
The APS serial interface and the REFCLK input operate similar to the optical module interfaces
except they are design for 622.08 MHz operation. The APECLV input controls the ECL levels
for the APSI[1:0]+/- inputs, APSO[1:0]+/- outputs and the REFCLK input. Illustrate the
recommended configurations for both types of ECL voltage levels when connecting to optical
modules. Note that the APSI[1:0]+/- and REFCLK inputs are internally terminated with a 100
ohm resistor between the differential inputs.
The APECLV must be set appropriately to configure the APSI[1:0]+/- inputs, APSO[1:0]+/-
outputs and REFCLK input for the termination scheme used. In these configurations, the traces
are double terminated (terminated at the source and sink). The APREF resistor must be set to
1 Kohm.
The 50 ohm control impedance traces must be less than 4 cm in length to reduce the effect of
signal reflections between the two S/UNI-8x155. If the APS traces are longer than 4cm (for
instance, the APS traces travel over a backplane), the APSO[1:0]+/- outputs should be buffered
using standard ECL buffers. The ECL buffers will ensure proper signal levels at the
APSI[1:0]+/- with little waveform overshoot or undershoot. Figure 39 illustrates this
configuration showing the ECL buffer. In this configuration, the APS traces are single
terminated (terminated at sink) and the APREF resistor must be 2 Kohms.
When a APSI[1:0]+/- PECL input is not being used, the positive differential input must be tied
to digital power (VDD) and the negative differential input must be tied to digital ground (VSS).
In all cases, the PECL inputs must be driven with a differential voltage (do not connect both
pins to VDD or VSS). When a APSO[1:0]+/- PECL output is not being used, both the positive
and negative differential outputs of the PECL output may be tied both to digital ground (VSS).
If all APSO[1:0]+/- outputs are not being used, the PECL drivers may be powered down by
connect the APREF1 to digital power (VDD) and the APREF0 to digital ground (VSS).
220W
330W
+3.3V
V
(2.0V)
(OMD Supply)
BB
237W
698W
S/UNI®-8x155 ASSP Telecom Standard Product Data Sheet
+5.0V
V
(3.7V)
(OMD Supply)
BB
Released
408