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RECOMMENDED INDUCTOR AND CAPACITOR VALUES BY APPLICATION

CLASS-D REQUIREMENTS

DECOUPLING CAPACITORS

INPUT CAPACITORS

)

I I

1

f =

c

(2

R C

´ p

´

(6)

TPA2013D1

SLOS520 – AUGUST 2007

Use Table 4 as a guide for determining the proper inductor and capacitor values.

Table 4. Recommended Values

Class-D

Class-D

Minimum

Required

Max

Output

L

Inductor Vendor

Capacitor Vendor

Load

ΔV

Power

(A)

(

μH)

Part Numbers

(

μF)

Part Numbers

(

Ω)

(V)

(V)

(mVpp)

3.3

10

Toko DE2812C

Kemet C1206C106K8PACTU

1

8

3

4.3

0.70

30

Coilcraft DO3314

Murata GRM32ER61A106KA01B

Murata LQH3NPN3R3NG0

Taiyo Yuden LMK316BJ106ML-T

4.7

22

Murata LQH32PN4R7NN0

1.6

8

3

5.5

1.13

30

Murata GRM32ER71A226KE20L

Toko DE4514C

Taiyo Yuden LMK316BJ226ML-T

Coilcraft LPS4018-472

3.3

33

2

4

3

4.6

1.53

30

Murata LQH55PN3R3NR0

TDK C4532X5R1A336M

Toko DE4514C

6.2

47

2.3

4

1.8

5.5

2

30

Sumida

Murata GRM32ER61A476KE20L

CDRH5D28NP-6R2NC

Taiyo Yuden LMK325BJ476MM-T

(1)

All power levels are calculated at 1% THD unless otherwise noted

(2)

All values listed are for ceramic capacitors. The correction factor of 2 is included in the values.

The TPA2013D1 is a high-performance Class-D audio amplifier that requires adequate power supply decoupling

to

ensure

the

efficiency

is

high

and

total

harmonic

distortion

(THD)

is

low.

Place

a

low

equivalent-series-resistance (ESR) ceramic capacitor, typically 1

μF as close as possible to the device VDD lead.

This choice of capacitor and placement helps with higher frequency transients, spikes, or digital hash on the line.

Additionally, placing this decoupling capacitor close to the TPA2013D1 is important for the efficiency of the

Class-D amplifier, because any resistance or inductance in the trace between the device and the capacitor can

cause a loss in efficiency. Place a capacitor of 10

μF or greater between the power supply and the boost

inductor. The capacitor filters out high frequency noise. More importantly, it acts as a charge reservoir, providing

energy more quickly than the board supply, thus helping to prevent any droop.

The TPA2013D1 does not require input coupling capacitors if the design uses a differential source that is biased

within the common mode input range. Use input coupling capacitors if the input signal is not biased within the

recommended common-mode input range, if high pass filtering is needed, or if using a single-ended source.

The input capacitors and input resistors form a high-pass filter with the corner frequency, fc, determined in

Equation 6.

The value of the input capacitor is important to consider as it directly affects the bass (low frequency)

performance of the circuit. Speakers in wireless phones cannot usually respond well to low frequencies, so the

corner frequency can be set to block low frequencies in this application. Not using input capacitors can increase

output offset.

Use Equation 7 to find the required the input coupling capacitance.

Copyright © 2007, Texas Instruments Incorporated

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