DS1650 Datasheet, PDF (23/26 Pages) National Semiconductor (TI) – Quad Differential Line Receivers

Firmware Setting
Please refer to another document for detailed description
of firmware setting.
Thermal Considerations
For continuous operation, do not exceed absolute
maximum junction temperature. The maximum power
dissipation depends on the thermal resistance of the IC
package, PCB layout, rate of surrounding airflow, and
difference between junction and ambient temperature.
The maximum power dissipation can be calculated by
the following formula :
PD(MAX) = (TJ(MAX)  TA) / JA
where TJ(MAX) is the maximum junction temperature,
TA is the ambient temperature, and JA is the junction to
ambient thermal resistance.
For recommended operating condition specifications,
the maximum junction temperature is 125C. The
junction to ambient thermal resistance, JA, is layout
dependent. For WL-CSP-48B 3x3.4 package, the
thermal resistance, JA, is 27.2C/W on a standard
JEDEC 51-7 four-layer thermal test board. The
maximum power dissipation at TA = 25C can be
calculated by the following formula :
PD(MAX) = (125C  25C) / (27.2C/W) = 3.67W for
WL-CSP-48B 3x3.4 package
The maximum power dissipation depends on the
operating ambient temperature for fixed TJ(MAX) and
thermal resistance, JA. The derating curve in Figure
RT1650
16 allows the designer to see the effect of rising
ambient temperature on the maximum power
dissipation.
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
0
Four-Layer PCB
25
50
75
100
125
Ambient Temperature (°C)
Figure 16. Derating Curve of Maximum Power
Dissipation
Layout Considerations
Follow the PCB layout guidelines for optimal
performance of the IC.
 Keep the traces of main current paths as short and
wide as possible.
 Place the capacitors as close as possible to the IC.
 Power ground should be as large as possible and
connected to a power plane for thermal dissipation.
Copyright © 2015 Richtek Technology Corporation. All rights reserved.
DS1650-00 July 2015
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
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