TSH511CFT(2002) View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
TSH511CFT
(Rev.:2002)
(Rev.:2002)
STMicroelectronics
TSH511CFT Datasheet PDF : 18 Pages
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TSH511
The comparator and the CMUTE capacitor gener-
ate the fade-in and fade-out control ramps for the
audio buffers. The Squelch has been designed
with particular attention to avoid audio pop-noise.
Figure 6 : Squelch schematic
The Audio Buffers can also drive the other usual
impedances used in audio: 32Ω, 600Ω and 10kΩ
(see the corresponding distorsion curves).
The high input impedances of the Audio Buffers
reduce the coupling capacitors to less than 0.1 µF
allowing space and cost saving.
Standby section
Depending on the states of the logic inputs SBY1
and SBY2, RX2 and the Audio Buffer2 can be
disabled separately. The TSH511 receiver can
adapt to different applications by using SBY1 &
SBY2 standby pins:
The squelch section is driven by the receiver RX1
but controls both audio buffers.
Audio Buffer sections
The audio signal from a FM demodulator enters
into the 6dB/octave low-pass filter for de-empha-
sis. 50µs and 75µs are standard de-emphasis val-
ues.
After the de-emphasis network, the potentiometer
controls the volume.
The Rail-to-Rail output stage of each Audio Buffer
is able to drive 20 mW into 16Ω at 2.3V supply
voltage. In this condition, the distortion is typically
0.3% before saturation.
SBY1
pin 32
Low
Low
High
SBY2
pin 31
Low
High
Low
RX1 &
audio RX2
buffer1
ON ON
ON OFF
High High ON OFF
audio typical
buffer 2 use
ON
ON
OFF
stereo
mono on
the two
outputs
mono on
one out-
put
In the standard stereo mode, the configuration is:
SBY1 = SBY2 = ’Low’
In mono mode with one load(example: a single
loadspeaker), RX2 and Audio Buffer 2 are
disabled, the configuration is SBY1 = SBY2 =
’High’.
In mono mode with a stereo load (example: a
stereo headphone), the configuration is SBY1 =
’high’, SBY2 = ’Low’.
A pin connected to Vcc is at ’High’ state, and if
connected to GND is at ’Low’ state.
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