Datasheet

EN
VFB
VREG5
SS
VIN
VBST
SW
PGND
ANALOG
GROUND
TRACE
SOFT
START
CAP
BIAS
CAP
FEEDBACK
RESISTORS
TO ENABLE
CONTROL
VIN INPUT
BYPASS
CAPACITOR
VIN
POWER GROUND
Additional
Thermal
Vias
Additional
Thermal
Vias
BOOST
CAPACITOR
OUTPUT
INDUCTOR
OUTPUT
FILTER
CAPACITOR
VOUT
Connection to
POWER GROUND
on internal or
bottom layer
EXPOSED
POWERPAD
AREA
VIN INPUT
BYPASS
CAPACITOR
TPS54427
SLVSB43A –NOVEMBER 2011–REVISED JUNE 2013 www.ti.com
LAYOUT CONSIDERATIONS
1. The TPS54427 can supply relatively large current up to 4A. So heat dissipation may be a concern. The top
side area adjacent to the TPS54427 should be filled with ground as much as possible to dissipate heat.
2. The bottom side area directly below the IC should a dedicated ground area. It should be directed connected
to the thermal pad of the using vias as shown. The ground area should be as large as practical. Additional
internal layers can be dedicated as ground planes and connected to vias as well.
3. Keep the input switching current loop as small as possible.
4. Keep the SW node as physically small and short as possible to minimize parasitic capacitance and
inductance and to minimize radiated emissions. Kelvin connections should be brought from the output to the
feedback pin of the device.
5. Keep analog and non-switching components away from switching components.
6. Make a single point connection from the signal ground to power ground.
7. Do not allow switching current to flow under the device.
8. Keep the pattern lines for VIN and PGND broad.
9. Exposed pad of device must be connected to PGND with solder.
10. VREG5 capacitor should be placed near the device, and connected PGND.
11. Output capacitor should be connected to a broad pattern of the PGND.
12. Voltage feedback loop should be as short as possible, and preferably with ground shield.
13. Lower resistor of the voltage divider which is connected to the VFB pin should be tied to SGND.
14. Providing sufficient via is preferable for VIN, SW and PGND connection.
15. PCB pattern for VIN, SW, and PGND should be as broad as possible.
16. VIN Capacitor should be placed as near as possible to the device.
Figure 16. TPS54427 Layout
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