ISL6208C_14 Datasheet, PDF (10/11 Pages) Intersil Corporation – High Voltage Synchronous Rectified Buck MOSFET Drivers

ISL6208C
Layout Considerations
Reducing Phase Ring
The parasitic inductances of the PCB and power devices (both
upper and lower FETs) could cause increased PHASE ringing,
which may lead to voltages that exceed the absolute maximum
rating of the devices. When PHASE rings below ground, the
negative voltage could add charge to the bootstrap capacitor
through the internal bootstrap diode. Under worst-case
conditions, the added charge could overstress the BOOT and/or
PHASE pins. To prevent this from happening, the user should
perform a careful layout inspection to reduce trace inductances,
and select low lead inductance MOSFETs and drivers. D²PAK and
DPAK packaged MOSFETs have high parasitic lead inductances,
as opposed to SOIC-8. If higher inductance MOSFETs must be
used, a Schottky diode is recommended across the lower
MOSFET to clamp negative PHASE ring.
A good layout would help reduce the ringing on the phase and
gate nodes significantly:
• Avoid using vias for decoupling components where possible,
especially in the BOOT-to-PHASE path. Little or no use of vias
for VCC and GND is also recommended. Decoupling loops
should be short.
• All power traces (UGATE, PHASE, LGATE, GND, VCC) should be
short and wide, and avoid using vias. If vias must be used, two
or more vias per layer transition is recommended.
• Keep the SOURCE of the upper FET as close as thermally
possible to the DRAIN of the lower FET.
• Keep the connection in between the SOURCE of lower FET and
power ground wide and short.
• Input capacitors should be placed as close to the DRAIN of the
upper FET and the SOURCE of the lower FET as thermally
possible.
Note: Refer to Intersil Tech Brief TB447 for more information.
Thermal Management
For maximum thermal performance in high current, high
switching frequency applications, connecting the thermal pad of
the DFN to the power ground with multiple vias is recommended.
This heat spreading allows the part to achieve its full thermal
potential.
Revision History
The revision history provided is for informational purposes only and is believed to be accurate, but not warranted. Please go to web to make sure you
have the latest revision.
DATE
REVISION
CHANGE
November 29, 2012
FN8395.0 Initial Release.
About Intersil
Intersil Corporation is a leader in the design and manufacture of high-performance analog, mixed-signal and power management
semiconductors. The company's products address some of the fastest growing markets within the industrial and infrastructure,
personal computing and high-end consumer markets. For more information about Intersil or to find out how to become a member of
our winning team, visit our website and career page at www.intersil.com.
For a complete listing of Applications, Related Documentation and Related Parts, please see the respective product information page.
Also, please check the product information page to ensure that you have the most updated datasheet: ISL6208C
To report errors or suggestions for this datasheet, please go to: www.intersil.com/askourstaff
Reliability reports are available from our website at: http://rel.intersil.com/reports/search.php
For additional products, see www.intersil.com/en/products.html
Intersil products are manufactured, assembled and tested utilizing ISO9000 quality systems as noted
in the quality certifications found at www.intersil.com/en/support/qualandreliability.html
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time
without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be
accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third
parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
10
FN8395.0
November 29, 2012