SY55859L_10 MICREL [Micrel Semiconductor], SY55859L_10 Datasheet - Page 8

• Manufacturer Part Number: SY55859L_10
• Description: 3.3V, 3.2Gbps Dual 2X2 Crosspoint Switch
• Manufacturer: MICREL [Micrel Semiconductor]

Functional Characteristics
SY55859L is a dual cross point with excellent pin-to-pin
and part-to-part skew matching. As shown in table 1,
based on the logic value at TTL input SELA0, output
QA0 replicates either input DA0 or DA1. TTL input
SELA1 selects whether output QA1 replicates input DA0
or DA1. As shown in table 2, TTL inputs SELB0 and
SELB1 perform similarly for outputs QB0 and QB1
respectively, choosing between inputs DB0 or DB1.
If the two control inputs are tied together, SY55859L
behaves as a redundant distribution device. Depending
on the state of the combined control inputs, QA0 and
QA1 will both replicate either DA0 or DA1. If the two
Micrel, Inc.
January 2010
SELA0
SELA0
CTL
CTL
CTL
CTL
0
0
1
1
0
0
1
1
SELA1
SELA1
/CTL
/CTL
CTL
CTL
0
1
0
1
0
1
0
1
Table 1. Input to Output Connectivity, Crosspoint A
Table 2. Input to Output Connectivity, Crosspoint B
Opposite
Opposite
Same
Same
QA0
QA0
DA0
DA0
DA1
DA1
DA0
DA0
DA1
DA1
8
control inputs are made the logical complement of each
other, the SY55859L functions as a crosspoint, either
sending DA0 to QA0 and DA1 to QA1, or sending DA0
to QA1 and DA1 to QA0. The same applies to channel
B.
SY85859L’s CML outputs are source terminated to 50
individually, 100
parallel terminated, also to 50 . This improves signal
integrity. With all terminations on chip, high-speed
interfacing is greatly simplified, eliminating the need for
external termination passive components. Figures 1 and
2 show the input and output structures.
Opposite
Opposite
Same
Same
QA1
QA1
DA0
DA1
DA0
DA1
DA0
DA1
DA0
DA1
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differentially. The CML inputs are
Redundant Distribution
Redundant Distribution
or [phone]
Fanout Buffer
Fanout Buffer
Fanout Buffer
Fanout Buffer
M9999-012110-A
Dual Buffer
Dual Buffer
Dual Buffer
Dual Buffer
Crosspoint
Crosspoint
Function
Function
SY55859L