GS2989

Final Data Sheet

Rev.6

GENDOC-052133

July 2015

15 of 20

Semtech

www.semtech.com

•

High-speed traces are round-curved (rather than 45° or 90° angles) to minimize

impedance variations due to change of PCB trace width

Note: For more recommendations on Trace Lengths, ORL Inductor Values and other PCB

Layout Considerations, please refer to Semtech’s GS2989 Design Guide

(Doc ID 52070).

5.2 Typical Application Circuit

Figure 5-1: Typical Application Circuit

DDI

2

DDI

3

SDO1

12

SDO1

11

SDO2

10

SDO2

9

RSET

5

GS2989

VCC_Term

10n

GND

75R

4u7

4u7

4u7

4u7

75R

VCC_Term

VCC_Term

10n

75R

10n

GND

GND

4u7

4u7

75R

75R

75R

75R

75R

5n6*

5n6*

GND

VCC

GND

VCC

10n

10n

R*

* Typical value: varies with layout, and represents a trade-off

between good eye shape and output return loss.

5n6 is the optimum value for an 800mV output swing

and 3.3V operation.

4n7 is the optimum value for an 800mV output swing and

2.5V operation.

6n8 is the optimum value for an 1800mV output swing.

NOTE: All resistors in Ohms, capacitors in Farads,

and inductors in Henrys, unless otherwise stated.

*Customer to choose resistor value.

5n6*

5n6*

**Please refer to section 4.2.