SC9270C/D 查看數據表（PDF） - Silan Microelectronics
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SC9270C/D Datasheet PDF : 12 Pages
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Silan
Semiconductors
SC9270C/D
5. INPUT CONFIGURATION
The input arrangement of the SC9270C/D provides a differential-input operational amplifier as well as a bias source
(VREF ) which is used to bias the inputs at mid-rail.
Provision is made for connection of a feedback resistor to the op-amp output (GS) for adjustment of gain. In a single-
ended configuration, the input pins are connected as shown in Fig.2 with the op-amp connected for unity gain and
VREF biasing the input at 1/2VDD.
Fig.8 shows the differential configuration, which permits the adjustment of gain with the feedback resistor R5.
C1 R1
C2 R4
R3
IN+
IN-
R5 GS
R2
VREF
SC9270C/D
+
-
DIFFERENTIAL INPUT AMPLIFIER
C1=C2=10nF
R1=R4=R5=100k
R2=60k, R3=37.5k
R3= R2*R5
R2+R5
All resistors are +/- 1% tolerance
All capacitors are +/- 5% tolerance
VOLTAGE GAIN (Av diff)= R5
R1
INPUT IMPEDANCE(Zi diff)=2 R12+ 1 2
C
Figure 8. Differential input configuration
6. POWER – DOWN AND INHIBIT MODE
A logic high applied to pin 6 (PWDN) will power the device to minimize the power consumption in a standby mode. It
stops the oscillator and the functions of the filters.
Inhibit mode is enabled by a logic high input to the pin 5 (INH). It inhibits the detection of 1633 Hz. The output code
will remain the same as the previous detected code (see table 2).
fLOW Fhigh KEY TOE Q4 Q3 Q2 Q1
fLOW Fhigh KEY TOE Q4 Q3 Q2 Q1
697 1209 1 H L L L H
697 1209 1 H L L L H
697 1336 2 H L L H L
697 1336 2 H L L H L
697 1477 3 H L L H H
697 1477 3 H L L H H
770 1209 4 H L H L L
770 1209 4 H L H L L
770 1336 5 H L H L H
770 1336 5 H L H L H
770 1477 6 H L H H L
770 1477 6 H L H H L
852 1209 7 H L H H H
852 1209 7 H L H H H
852 1336 8 H H L L L
852 1336 8 H H L L L
852 1477 9 H H L L H
852 1477 9 H H L L H
941 1336 0 H H L H L
941 1336 0 H H L H L
941 1209 * H H L H H
941 1209 * H H L H H
941 1477 # H H H L L
941 1477 # H H H L L
697 1633 A H H H L H 697
1633 A H
770 1633 B H H H H L
852 1633 C H H H H H
770 1633 B H
852 1633 C H
PREVIOUS DATA
941 1633 D H L L L L
941 1633 D H
--
-- ANY L Z Z Z Z
--
-- ANY L Z Z Z Z
Table 2: Truth table
INH = VSS
(Z: high impedance)
INH = VDD
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 1.1 2001.04.27
11
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