RT8170A Datasheet, PDF (44/45 Pages) Richtek Technology Corporation – Single-Phase Controller with Integrated Driver

RT8170A
Layout Considerations
PCB layout is critical to achieve low switching losses and
stable operation. The switching power stage requires
particular attention. If possible, mount all of the power
components on the top side of the board with their ground
terminals flushed against one another. Follow these
guidelines for the optimum PCB layout :
 Keep the high current paths short, especially at the
ground terminals.
 Keep the power traces and load connections short. This
is essential for high efficiency.
 When trade-offs in trace lengths must be made, it's
preferable to let the inductor charging path be longer
than the discharging path.
 Place the current sense component close to the
controller. ISENP and ISENN connections for current
limit and voltage positioning must be made using Kelvin
sense connections to guarantee current sense accuracy.
The PCB trace from the sense nodes should be
paralleled back to the controller.
 Route high speed switching nodes away from sensitive
analog areas (COMP, FB, ISENP, ISENN, etc...)
 Connect the exposed pad to the ground plane through
low impedance path. Recommend use of at least 5 vias
to connect to ground planes in PCB internal layers.
Copyright ©2013 Richtek Technology Corporation. All rights reserved.
www.richtek.com
44
is a registered trademark of Richtek Technology Corporation.
DS8170A-00 November 2013