6.25 Gbps, 4 × 4,
Digital Crosspoint Switch with EQ
AD8156
FEATURES
FUNCTIONAL BLOCK DIAGRAM
4 × 4, fully differential, nonblocking array
Configurable for dual 2 × 2 operation
DC to 6.25 Gbps per channel, NRZ data rate
Programmable input equalization compensates for over 40”
of FR-4 at 6.25 Gbps
Multicast and broadcast modes of operation
Programmable output swing
100 mV p-p to 1.6 V p-p differential
Power supply: 3.3 V ( 10%)
AD8156
INPUT
INPUT
OUTPUT
DRIVERS
RECEIVERS EQUALIZATION
IN0P/N
OUT0P/N
EQ
EQ
EQ
EQ
IN1P/N
IN2P/N
OUT1P/N
OUT2P/N
4 × 4
SWITCH
IN3P/N
OUT3P/N
Low power
No EQ: 400 mW typical
CS
RST
UPD
WE
RE
MODE
D[3:0]
A[3:0]
Maximum EQ: 700 mW typical
CONTROL
LOGIC
Inputs: ac-coupled or dc-coupled
Wide set of dc-coupled input standards
3.3 V/2.5 V/1.8 V CML or 3.3 V LVPECL
Control: LVTTL- or LVCMOS-compatible
Low additive jitter: 25 ps p-p typical
Low random jitter: 0.8 ps rms
4
4
Figure 1.
Integrated 50 Ω termination impedance at inputs/outputs
Individual output disable for power savings
49-ball, 8 mm × 8 mm BGA, 1 mm pitch
APPLICATIONS
Backplane equalization
SONET/SDH
Gigabit Ethernet
XAUI
Fibre Channel
GENERAL DESCRIPTION
The AD8156, a member of the Xstream line of products, is a
high speed, fully differential, digital crosspoint switch. The part
can function as a 4 × 4 crosspoint switch with double-latched
memory, allowing simultaneous updates, or as a dual 2 × 2 with
direct output control. The AD8156 has low power dissipation,
typically 700 mW on 3.3 V with all outputs and input equalizers
active. It operates at any data rate from dc to 6.25 Gbps per port.
The AD8156 high speed inputs are compatible with both ac-
coupled and dc-coupled 3.3 V, 2.5 V, or 1.8 V CML, as well as
3.3 V LVPECL data levels. The control interface is LVTTL- and
LVCMOS-compatible at 3.3 V. All input and output termination
resistors are integrated for ease of layout and to minimize
impedance mismatch. Input equalization and unused outputs
can be individually disabled to minimize power dissipation.
Each input channel on the AD8156 has a programmable input
equalizer to compensate for signal loss over a backplane.
The AD8156 is packaged in a 49-ball, 8 mm × 8 mm, BGA
package with a 1 mm ball pitch. It operates over the industrial
temperature range of −40°C to 85°C.
Rev. 0
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responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
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