Texas Instruments SD303EVK Evaluation Board SD303EVK/NOPB SD303EVK/NOPB 데이터 시트

The SDI input connectors (J1 and J2) are 50

Ω SMA connectors.  The SD303/SD307 is initially configured for 100Ω 

differential input.  To configure the SD303/SD307 for 50

Ω single-ended input, remove R28 and place 49.9Ω 0402 

resistors in R9 and R10.  When using only one input, the other input should be terminated with a 50

Ω SMA 

termination. 
 
The SDO output connectors (J3 and J4 for the SD303; and J3, J4, J5, and J6 for the dual output SD307) are 75

Ω 

BNC connectors.  When using only one side of an output pair, the other side should be terminated with a 75

Ω BNC 

termination.  For example, when only using SDO0 on the LMH0307, SDO0

¯¯¯¯¯  should be terminated with a 75

Ω BNC 

termination. 
 

The red and black binding posts (J8 and J9) provide power for the LMH0303/LMH0307 device, and the USB 
connection provides power for the remaining board functions, including the microcontroller and the LEDs.  For 
proper operation, the SD303/SD307 should first be powered with a DC input voltage (between J8 and J9) of 
3.3V ± 5% (3.6V maximum), and then the USB cable should be connected between the evaluation board and 
the PC.  The POWER LED will flash Red while the board is powered from the 3.3 VDC supply alone, and then 
change to solid Green once the USB cable is connected to the PC.  The POWER LED will remain Green as long as 
the board is powered correctly. 
 

A jumper block should be placed on JP1 to connect the LMH0303/LMH0307 pins to the microcontroller.  The ALP 
software will not function correctly if this jumper block is not in place.  Separate jumpers may be used, but they 
must be placed to connect the following pins of JP1:  RSTI

¯¯¯¯  (pins 5-6), ENABLE (pins 7-8), SDA (pins 9-10), SCL 

(pins 11-12), SD/HD (pins 13-14), FAULT

¯¯¯¯¯¯  (pins 15-16), and RSTO

¯¯¯¯¯  (pins 17-18).  This jumper block (or individual 

jumpers) may be removed to control the LMH0303/LMH0307 pins externally, but then the microcontroller will no 
longer be able to communicate with the cable driver. 
 

The ENABLE push button switch controls ENABLE, and the ENABLE LED shows its state.  The ENABLE LED is 
Green when the cable driver is enabled (ENABLE = 1), and Red when the cable driver is disabled (ENABLE = 0).  
When the cable driver is disabled, it enters a deep power down mode, and Termination Fault detection and  LOS

¯¯¯¯ 

detection no longer function. 
 
If the LOSEN register bit (bit 4 of register 05h) is set, then the cable driver can be disabled with  LOS

¯¯¯¯ detection still 

functioning.  With LOSEN set,  LOS

¯¯¯¯ is combined with the ENABLE functionality.  In this mode, disabling the device 

by pushing the ENABLE switch will still power down the device completely (including powering down Termination 
Fault detection and  LOS

¯¯¯¯ detection), but if ENABLE is left active and the signal is removed from the input, the 

device will power down with the  LOS

¯¯¯¯ detection still functioning.  When the input signal is reapplied, the device will 

power back on. 

The SD/HD push button switch controls SD/HD, and the SD/HD LED shows its state.  The SD/HD LED is Green 
when the cable driver is configured for HD/3G edge rates (SD/HD = 0), and Red when the cable driver is configured 
for SD edge rates (SD/HD = 1).  The default setting for the SD/HD LED is Green for HD/3G edge rates. 

SD303/SD307 EVK User Guide 

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Rev 1.2 

© 2010, National Semiconductor Corp.