FDA803D datasheet(49/78 Pages) STMICROELECTRONICS

Part #	FDA803D

Description	1 x 45 W class D digital input automotive power amplifier with diagnostics, wide voltage operation range for car audio and telematic

PDF	78 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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49 / 78 page

DocID031487 Rev 2

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FDA803D

Additional features

12.1

AM operation mode

The device provides special functions in order to avoid EM interferences when the radio is

tuned on an AM station.

The first function consists in allowing the user to select a proper PWM switching frequency

through I2C interface, depending on the AM station selected by the tuner. The PWM

switching frequency selection is available only in case the I2S frame clock is 44.1 kHz or 48

kHz, as shown in Figure 60.

Figure 60. PWM switching frequency selection

Actually, the PWM spectrum of the output square wave can be controlled in AM band just in

case it is possible to fix the switching frequency, in other words without skipping any power

stage commutation (typical phenomenon for a class D amplifier close to the clipping). The

device provides an additional function called LRF (Low Radiation Function). This I2C option

assures a minimum duty cycle for the PWM output square wave avoiding any missing

pulses.

Figure 61. LRF effect on PWM output

FDA803D Datasheet(PDF) 49 Page - STMicroelectronics