C =

i

1

2

Z f

p

i

c

f

=

c

1

2

Z C

p

i

i

-3dB

IN

Input

Signal

20

TPA3136D2, TPA3136AD2

SLOS938D – MAY 2016 – REVISED MARCH 2017

www.ti.com

Product Folder Links: TPA3136D2 TPA3136AD2

Submit Documentation Feedback

Copyright © 2016–2017, Texas Instruments Incorporated

Typical Applications (continued)

pass filter with the corner frequency determined in Equation 2.

(2)

reconfigured as Equation 3.

(3)

and the feedback network to the load. This leakage current creates a dc offset voltage at the input to the

amplifier that reduces useful headroom. For this reason, a low-leakage tantalum or ceramic capacitor is the best

choice. When polarized capacitors are used, the positive side of the capacitor should face the amplifier input in

most applications as the dc level there is held at 3 V, which is likely higher than the source dc level. Note that it

is important to confirm the capacitor polarity in the application. Additionally, lead-free solder can create dc offset

voltages and it is important to ensure that boards are cleaned properly.

10.2.2.6 BSN and BSP Capacitors

The full H-bridge output stages use only NMOS transistors. Therefore, they require bootstrap capacitors for the

high side of each output to turn on correctly. A 0.22-μF ceramic capacitor, rated for at least 25 V, must be

connected from each output to its corresponding bootstrap input. Specifically, one 0.22-μF capacitor must be

connected from OUTPx to BSPx, and one 0.22-μF capacitor must be connected from OUTNx to BSNx. (See the

application circuit diagram in Figure 18.)

The bootstrap capacitors connected between the BSxx pins and corresponding output function as a floating

power supply for the high-side N-channel power MOSFET gate drive circuitry. During each high-side switching

cycle, the bootstrap capacitors hold the gate-to-source voltage high enough to keep the high-side MOSFETs

turned on.