BQ500414Q Datasheet, PDF (24/34 Pages) Texas Instruments – Qi Compliant Wireless Power Transmitter Manager

bq500414Q
SLUSBE4B – JANUARY 2014 – REVISED JUNE 2014
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11.2 Layout Example
A DC-DC buck regulator is used to step down the system voltage to the 3.3-V supply to the bq500414Q. The
system voltage could be 12-V, or 6-V – 16-V depending on where the buck regulator input is. With such a step-
down ratio, switching duty-cycle will be low and the regulator will be mostly freewheeling. Therefore, place the
freewheeling diode current loop as close to the switching regulator as possible (loop in red). Place the buck
inductor and power loop as close to that as possible (loop in blue).
Buck Inductor
and
Power Loop
Diode Current
Loop
Figure 14. DC-DC Buck Regulator Layout
Make sure the bypass capacitors intended for the bq500414Q 3.3-V supply are actually bypassing these supply
pins (pin 33 V33D and pin 34 V33A) to solid ground plane. This means they need to be placed as close to the
device as possible and the traces must be as wide as possible.
Figure 15. Bypass Capacitors Layout
Make sure the bq500414Q has a continuous flood connection to the ground plane.
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