TS4890IST datasheet(37/46 Pages) STMICROELECTRONICS

37 / 46 page

DocID8396 Rev 7

37/46

TS4890

Application information

and the theoretical value of the -3 dB cut of higher frequency is 2 MHz/3 = 660 kHz. We can

keep this value or limiting the bandwidth by adding a capacitor Cfeed, in parallel on Rfeed.

Then:

So, we could use for Cfeed a 220 pF capacitor value that gives 24 kHz. Now, we can choose

the value of Cb with the constraint THD+N in 20 Hz to 20 kHz < 0.5% @ Pout=0.45 W. If you

refer to the closest THD+N vs frequency measurement: Figure 71 (Vcc=3.3 V, Gv=10), with

Cb = 1 µF, the THD+N vs frequency is always below 0.4%. As the behavior is the same with

Vcc = 5 V (Figure 67), Vcc = 2.6 V (Figure 67). As the gain for these measurements is

higher (worst case), we can consider with Cb = 1 µF, Vcc = 3.5 V and Gv = 6, that the

THD+N in 20 Hz to 20 kHz range with Pout = 0.45 W is lower than 0.4%. In the following

tables, you could find three another examples with values required for the demoboard.

Remark: components with (*) marking are optional.

Application n°1: 20 Hz to 20 kHz bandwidth and 6 dB gain BTL power

amplifier

Table 9. Components

Designator

Part type

22 k / 0.125 W

Short-circuit

(Vcc-Vf_led)/If_led

10 k/0.125 W

470 nF

100 µF

100 nF

Short-circuit

C10

Short-circuit

C12

1 µF

S1, S2, S6, S7

2 mm insulated plug

10.16 mm pitch

3 connector 2.54 mm

pitch

PCB phono jack

Led 3 mm

TS4890ID or TS4890IS

Rfeed

Rin

-----------------

FEED

πR

FEEDFCH

------------------------------------

265pF

TS4890IST 数据表(PDF) 37 Page - STMicroelectronics

TS4890IST 数据表(HTML) 37 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46

数据表下载

链接网址

TS4890IST 数据表(PDF) 37 Page - STMicroelectronics

TS4890IST 数据表(HTML) 37 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46

数据表 下载

链接网址

数据表下载