TDA8552T_02 Datasheet, PDF (7/27 Pages) NXP Semiconductors – 2 x 1.4 W BTL audio amplifiers with digital volume control and headphone sensing

NXP Semiconductors
2 x 1.4 W BTL audio amplifiers with digital
volume control and headphone sensing
Product specification
TDA8552T; TDA8552TS
Mode select pin
The device is in the standby mode (with a very low current
consumption) if the voltage at the MODE pin is between
V_DD and V_DD − 0.5 V. At a mode select voltage level of less
than 0.5 V the amplifier is fully operational. In the range
between 1 V and V_DD − 1 V the amplifier is in the mute
condition. The mute condition is useful for using it as a ‘fast
mute’, in this mode the output signal is suppressed, while
the volume setting remains at its value. It is advised to
keep the device in the mute condition while the input
capacitor is being charged. This can be achieved by
holding the MODE pin at a level of 0.5V_DD, or by waiting
approximately 100 ms before giving the first volume-UP
pulses.
Headphone sense pin (HPS)
A headphone can be connected to the amplifier by using a
coupling capacitor for each channel. The common ground
pin of the headphone is connected to the ground of the
amplifier, see Fig.4. By using the HPS pin as illustrated in
Fig.4, the TDA8552T detects if a headphone jack plug is
inserted into the connector.
When no headphone is plugged in, the voltage level at the
HPS pin will remain LOW. A voltage less than V_DD − 1 V at
the HPS pin will keep the device in the BTL mode, thus the
loudspeakers can be operational. If the HPS pin is not
connected then the device will remain in the BTL mode.
When a headphone is plugged into the connector, the
voltage at the HPS pin will be set to V_DD. The device then
switches to the Single-Ended (SE) mode, this means that
the slave power amplifiers at the outputs OUT1− and
OUT2− will be switched to the standby mode. This results
in floating outputs OUT1− and OUT2−, the loudspeaker
signal is thus attenuated by approximately 80 dB and only
the headphone can operate.
One of the benefits of this system is that the loudspeaker
current does not flow through the jack connector switch,
which could give some output power loss. The other
benefit is that the quiescent current is reduced when the
headphone jack is inserted.
2002 Jan 04
7