DS10CP154 National Semiconductor, DS10CP154 Datasheet - Page 9

• Manufacturer Part Number: DS10CP154
• Description: 1.5 Gbps LVDS Crosspoint Switch
• Manufacturer: National Semiconductor

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Functional Description
The DS10CP154 is a 1.5 Gbps 4x4 LVDS digital crosspoint
switch optimized for high-speed signal routing and switching
over lossy FR-4 printed circuit board backplanes and bal-
anced cables. The DS10CP154 operates in two modes: Pin
Mode (EN_smb = 0) and SMBus Mode (EN_smb = 1).
When in the Pin Mode, the switch is fully configurable with
external pins. This is possible with two input select pins per
output (e.g. S00 and S01 pins for OUT0).
In the Pin Mode, feedback from the LOS (Loss Of Signal)
monitor circuitry is not available (there is not an LOS output
pin).
When in the SMBus Mode, the full switch configuration and
SoftPWDN can be programmed via the SMBus interface. In
addition, by using the SMBus interface, a user can obtain the
feedback from the built-in LOS circuitry which detects an open
inputs fault condition.
In the SMBus Mode, the S00 and S01 pins become SMBus
clock (SCL) input and data (SDA) input pins respectively; the
S10, S11, S21 and S21 pins become the User-Set SMBus
Slave Address input pins (ADDR0, 1, 2 and 3) while the S30
Switch Configuration Truth Tables
S01
S11
0
0
1
1
0
0
1
1
TABLE 1. Input Select Pins Configuration for the Output OUT0
TABLE 2. Input Select Pins Configuration for the Output OUT1
S00
S10
0
1
0
1
0
1
0
1
9
and S31 pins become non-functional (tieing these two pins to
either H or L is recommended if the device will function only
in the SMBus mode).
In the SMBus Mode, the PWDN pin remains functional. How
this pin functions in each mode is detailed in the following
sections.
DS10CP154 OPERATION IN THE PIN MODE
Power Up
In the Pin Mode, when the power is applied to the device
power suppy pins, the DS10CP154 enters the Power Up
mode when the PWDN pin is set to logic H. When in the Power
Down mode (PWDN pin is set to logic L), all circuitry is shut
down except the minimum required circuitry for the LOS and
SMBus Slave operation.
Switch Configuration
In the Pin Mode, the DS10CP154 operates as a fully pin-con-
figurable crosspoint switch. The following truth tables illus-
trate how the swich can be configured with external pins.
INPUT SELECTED
INPUT SELECTED
IN0
IN1
IN2
IN3
IN0
IN1
IN2
IN3
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