CLINK3V48BT-112 National Semiconductor, CLINK3V48BT-112 Datasheet - Page 6

• Manufacturer Part Number: CLINK3V48BT-112
• Description: KIT EVAL 48BIT DS90CR481/2/3/4
• Manufacturer: National Semiconductor

Specifications of CLINK3V48BT-112

• Main Purpose: Interface, Serializer, Deserializer (SERDES)
• Utilized Ic / Part: DS90CR481, DS90CR482, and DS90CR483
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -

Tx Features and Explanations
Pre-emphasis (PRE - pin 14/JP1):
1. This feature enables you to overcome cable capacitance through the LVDS
2. It affects Tx A0-A7 and CLKs LVDS outputs only.
3. To disable this function, pin 14 must be tied “low”. LVDS output drive will then be at
4. The input will be pulled low (0.7V) if no jumper is used. To adjust the level of pre-
PLL range select (PLLSEL - pin 15/JP5):
1. High-range is selected by tying pin 15 “high”.
2. Low-range is selected by tying pin 15 “low”. This feature provides lower noise in the
NOTE: Refer to the “Application Notes” on the back of the data sheet for complete
description of each feature.
interface. This function provides additional instantaneous current during switching
transitions. NOTE: This function does NOT affect Rx output drive.
its standard value of 3.5mA.
emphasis, place a jumper on JP1 to Vcc. R48 will now be connected. R48 is a 2K
potentiometer. Use a number 1.4mm jewelers screwdriver to adjust R48. Turning
clockwise will increase the pre-emphasis value. Turning counterclockwise will
decrease the pre-emphasis value. R48 should be adjusted to reduce overshoot.
Too much pre-emphasis can create an overshoot condition at the rising edge and an
undershoot condition on the falling edge. Icc will increase but allows you to drive
longer cables. Too little pre-emphasis will not allow you to drive longer cables.
Monitor any one of the LVDS lines (A0-A7) or CLK1 for a visual confirmation of its
effect. It is recommended that you monitor the LVDS signals with a differential
probe. If a differential probe is not used, a single ended probe can be used for a
quick check.
lower range of the PLL.
National Semiconductor Corporation
Interface Products
LIT# CLINK3V48BT-112-UM
Date 07/15/08
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