Zxld1370, Application information – Diodes ZXLD1370 User Manual
Page 33
ZXLD1370
Document number: DS32165 Rev. 5 - 2
33 of 39
September 2012
© Diodes Incorporated
ZXLD1370
A Product Line of
Diodes Incorporated
Application Information
(cont.)
PCB Layout Considerations
PCB layout is a fundamental activity to get the most of the device in all configurations. In the following section it is possible to find some
important insight to design with the ZXLD1370 both in Buck and Buck-Boost/Boost configurations.
Figure 39 Circuit Layout
Here are some considerations useful for the PCB layout:
•
In order to avoid ringing due to stray inductances, the inductor L1, the anode of D1 and the drain of Q1 should be placed as close
together as possible.
•
The shaping capacitor C1 is fundamental for the stability of the control loop. To this end it should be placed no more than 5mm from
the SHP pin.
•
Input voltage pins, VIN and VAUX, need to be decoupled. It is recommended to use two ceramic capacitors of 2.2uF, X7R, 100V (C3
and C4). In addition to these capacitors, it is suggested to add two ceramic capacitors of 1uF, X7R, 100V each (C2, C8), as well as a
further decoupling capacitor of 100nF close to the VIN/VAUX pins (C9). VIN and VAUX pins can be short-circuited when the device is
used in buck mode, or can be driven from a separate supply.
SHP Pin
V
IN
/ V
AUX
Decoupling
Inductor, Switch and
Freewheeling Diode