Tr i p ath Technol ogy, I n c. - Techni cal In fo rma t io n

28

TK2150 – Rev. 1.0/12.02

loads and the impedance they present changes over frequency and from speaker model to

speaker model.

Tripath recommends designing the filter as a 2nd order, 100kHz LC filter. Tripath has obtained

The core material of the output filter inductor has an effect on the distortion levels produced by a

TK2150 amplifier. Tripath recommends low-mu type-2 iron powder cores because of their low

used on the EB-TK2150 was a T106-2 wound with 44 turns of 22AWG wire.

Tripath also recommends that an RC damper be used after the LC low-pass filter. No-load

operation of a TK2150 amplifier can create significant peaking in the LC filter, which produces

strong resonant currents that can overheat the output MOSFETs and/or other components. The

20

Bridging the TK2150

The TK2150 can be bridged by returning the signal from VP1 to the input resistor at INV2. OUT1

will then be a gained version of VP1, and OUT2 will be a gained and inverted version of OAOUT1

(see Figure 8). When the two amplifier outputs are bridged, the apparent load impedance seen

by each output is halved, so the current capability of the output MOSFETs, as well their power

dissipation capability, must be accounted for in the design. In addition, the higher peak currents

caused by driving lower impedance loads will cause additional ringing on the outputs. Thus, the

layout and supply decoupling for low impedance (below 8 ohms) bridged applications must be

extremely good to minimize output ringing and to ensure proper amplifier performance.

OAOUT1

INV1

C

I

22

23

+

V5

AGND

R

F

R

I

-

+

OAOUT2

INV2

27

28

V5

AGND

20k

-

+

BIASCAP

TC2001

INPUT1

20k

Figure 8: Input Stage Setup for Bridging