FDA903U datasheet(48/80 Pages) STMICROELECTRONICS

номер детали	FDA903U

подробное описание детали	1 x 45 W class D digital input automotive power amplifier with ILoad current monitoring, wide voltage operation range for car audio and telematic

PDF	80 Pages

Scroll/Zoom	100%

производитель	STMICROELECTRONICS [STMicroelectronics]

домашняя страница	http://www.st.com

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48 / 80 page

Additional features

FDA903U

48/80

DS12498 Rev 2

Additional features

11.1

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 63.

Figure 63. 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 64. LRF effect on PWM output

FDA903U датащи(PDF) 48 Page - STMicroelectronics