TDA7491LP datasheet(26/37 Pages) STMICROELECTRONICS

Part #	TDA7491LP

Description	2 x 5-watt dual BTL class-D audio amplifier

PDF	37 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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26 / 37 page

Applications information

TDA7491LP

26/37

Doc ID 13541 Rev 5

5.3

Gain setting

The gain of the TDA7491LP is set by the two inputs, GAIN0 (pin 30) and GAIN1 (pin 31).

Internally, the gain is set by changing the feedback resistors of the amplifier.

5.4

Input resistance and capacitance

The input impedance is set by an internal resistor Ri = 68 k

Ω (typical). An input capacitor

(Ci) is required to couple the AC input signal.

The equivalent circuit and frequency response of the input components are shown in

Figure 29. For Ci = 220 nF the high-pass filter cut-off frequency is below 20 Hz:

fc = 1 / (2 *

π * Ri * Ci)

Figure 29.

Device input circuit and frequency response

Table 7.

Gain settings

Voltage level on pin GAIN0

Voltage level on pin GAIN1

Nominal gain, Gv (dB)

L(1)

Refer to VinL and VinH in Table 5: Electrical specifications on page 10 for the drive levels for L and H

H(1)

Input

signal

TDA7491LP Datasheet(PDF) 26 Page - STMicroelectronics