LTM4622_15 Datasheet, PDF (20/26 Pages) Linear Technology – Dual Ultrathin 2.5A Step-Down DC/DC Module Regulator

LTM4622
APPLICATIONS INFORMATION
SAFETY CONSIDERATIONS
The LTM4622 modules do not provide galvanic isolation
from V_IN to V_OUT. There is no internal fuse. If required,
a slow blow fuse with a rating twice the maximum input
current needs to be provided to protect each unit from
catastrophic failure. The device does support thermal
shutdown and over current protection.
LAYOUT CHECKLIST/EXAMPLE
The high integration of LTM4622 makes the PCB board
layout very simple and easy. However, to optimize its
electrical and thermal performance, some layout consid-
erations are still necessary.
nn _{Use large PCB copper areas for high current paths,}
including V_IN, GND, V_OUT1 and V_OUT2. It helps to
minimize the PCB conduction loss and thermal stress.
nn _{Place high frequency ceramic input and output}
capacitors next to the V_IN, PGND and V_OUT pins to
minimize high frequency noise.
nn _{Place a dedicated power ground layer underneath}
the unit.
nn _{To minimize the via conduction loss and reduce}
module thermal stress, use multiple vias for
interconnection between top layer and other
power layers.
nn _{Do not put via directly on the pad, unless they are}
capped or plated over.
nn _{Use a separated SGND ground copper area for}
components connected to signal pins. Connect the
SGND to GND underneath the unit.
nn _{For parallel modules, tie the VOUT, VFB, and COMP}
pins together. Use an internal layer to closely con-
nect these pins together. The TRACK pin can be
tied a common capacitor for regulator soft-start.
nn _{Bring out test points on the signal pins for}
monitoring.
Figure 23 gives a good example of the recommended layout.
20
4622 F23
Figure 23. Recommended PCB Layout
4622f
For more information www.linear.com/LTM4622