LM3876 datasheet(7/19 Pages) NSC

7 / 19 page

External Components Description (Continued)

(

Figures 1, 2)

Components

Functional Description

10.

(Note 15)

At higher frequencies feedback resistance works with C

f to provide lower AC Gain in conjunction with Rf1

and Ri. A high frequency pole (lowpass roll-off) exists at:

c = [Rf1 Rf2 (s + 1/Rf2Cf)]/[(Rf1 +Rf2)(s + 1/Cf(Rf1 +Rf2))]

11.

(Note 15)

Compensation capacitor that works with R

f1 and Rf2 to reduce the AC Gain at higher frequencies.

12.

Mute resistance set up to allow 0.5 mA to be drawn from pin 8 to turn the muting function off.

→R

M is calculated using: RM ≤ (|VEE| − 2.6V)/I8 where I8 ≥ 0.5 mA. Refer to the Mute Attenuation vs

Mute Current curves in the Typical Performance Characteristics section.

13.

Mute capacitance set up to create a large time constant for turn-on and turn-off muting.

14.

(Note 15)

Works with C

SN to stabilize the output stage by creating a pole that eliminates high frequency oscillations.

15.

(Note 15)

Works with R

SN to stabilize the output stage by creating a pole that eliminates high frequency oscillations.

c = 1/(2πRSNCSN)

16.

(Note 15)

Provides high impedance at high frequecies so that R may decouple a highly capacitive load

17.

(Note 15)

and reduce the Q of the series resonant circuit due to capacitive load. Also provides a low impedance at

low frequencies to short out R and pass audio signals to the load.

18.

Provides power supply filtering and bypassing.

19.

Mute switch that mutes the music going into the amplifier when opened.

Note 15: Optional components dependent upon specific design requirements. Refer to the Application Information section for more information.

OPTIONAL EXTERNAL COMPONENT INTERACTION

Although the optional external components have specific desired functions that are designed to reduce the bandwidth and elimi-

nate unwanted high frequency oscillations they may cause certain undesirable effects when they interact. Interaction may occur

for components whose reactances are in close proximity to one another. One example would be the coupling capacitor, C

C, and

the compensation capacitor, Cf. These two components act as low impedances to certain frequencies which will couple signals

from the input to the output. Please take careful note of basic amplifier component functionality when designing in these compo-

nents.

The optional external components shown in

Figure 2 and described above are applicable in both single and split voltage supply

configurations.

Typical Performance Characteristics

Safe Area

DS011832-17

SPiKe

Protection Response

DS011832-18

Supply Current vs

Supply Voltage

DS011832-19

LM3876 bảng dữ liệu(PDF) 7 Page - National Semiconductor (TI)

LM3876 bảng dữ liệu(HTML) 7 Page - National Semiconductor (TI)

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

bảng dữ liệu tải về

Link URL