STV0056A STMicroelectronics, STV0056A Datasheet - Page 3

• Manufacturer Part Number: STV0056A
• Description: Video ICs Analog Sound/Video
• Manufacturer: STMicroelectronics
• Type: Audio DSPr

Specifications of STV0056A

• Maximum Operating Temperature: + 70 C
• Package / Case: PDIP-56
• Minimum Operating Temperature: 0 C
• Mounting Style: Through Hole
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PIN ASSIGNMENT (continued)
PIN DESCRIPTION
SOUND DETECTION
FMIN
This is the input to the two FM demodulators. It
feeds two AGC amplifiers with a bandwidth of at
least 5-10MHz. There is one amplifier for each
channel both with the same input. The AGC ampli-
fiers have a 0dB to +40dB range.
Z
Max input = 500mV
added together, when their phases coincide).
AGC L, AGC R
AGC amplifiers peak detector capacitor connec-
tions. The output current has an attack/decay ratio
of 1:32. That is the ramp up current is approxi-
mately 5 A and decay current is approximately
160 A. 11V gives maximum gain. These pins are
also driven by a circuit monitoring the voltage on
AMPLK L and AMPLK R respectively.
AMPLK L, AMPLK R
The outputs of amplitude detectors LEFT and
RIGHT. Each requires a capacitor and a resistor to
GND. The voltage across this is used to decide
whether there is a signal being received by the FM
detector. The level detector output drives a bit in
the detector I
AMPLK L and AMPLK R drive also respectively
AGC L and AGC R. For instance when the voltage
on AMPLK L is > (V
V
IN
REF
Pin Number
= 5k , Min input = 2mV
from pin AGCL to reduce the AGC gain.
45
46
47
48
49
50
51
52
53
54
55
56
2
C bus control block.
REF
PP
PK OUT L
CPUMP R
PK OUT R
+ 1 V
AMPLK R
(max when all inputs are
A GND R
LEVEL L
PK IN L
DET R
U75 R
Name
A 12V
FC L
I
REF
PP
BE
per subcarrier.
) it sinks current to
Audio 12V Supply
Amplitude Detector Capacitor Left
FM PLL Filter Right
Deemphasis Time Constant Right
FM PLL Charge Pump Capacitor Right
Current Reference Resistor
Noise Reduction Peak Detector Output Right
Noise Reduction Peak Detector Output Left
Noise Reduction Level Left
Noise Reduction Peak Detector Input
Audio Roll-off Left
Audio Ground
DET L, DET R
Respectively the outputs of the FM phase detector
left and right.
This is for the connection of an external loop filter
for the PLL. The output is a push-pull current
source.
CPUMP L, CPUMP R
The output from the frequency synthesizer is a
push-pull current source which requires a capacitor
to ground to derive a voltage to pull the VCO to the
target frequency. The output is 100 A to achieve
lock and 2 A during lock to provide a tracking time
constant of approximately 10Hz.
V
This is the audio processor voltage reference used
through out the FM/audio section of the chip. As
such it is essential that it is well decoupled to
ground to reduce as far as possible the risk of
crosstalk and noise injection. This voltage is de-
rived directly from the bandgap reference of 2.4V.
The V
operation and 100 A when in stand-by.
I
This is a buffered V
to produce an accurate current reference, within
the chip, for the biasing of amplifiers with current
outputs into filters. It is also required for the Noise
reduction circuit to provide accurate roll-off fre-
quencies. This pin should not be decoupled as it
would inject current noise. The target current is
50 A 2% thus a 47.5k
REF
REF
REF
output can sink up to 500 A in normal
Function
REF
output to an off-chip resistor
1% is required.
STV0056A
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