Mask Option - Epson S1C63558 Technical Manual

CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (FSK Demodulator)

4.15.2 Mask option

The gain of the input amplifier shown in Figure 4.15.1.2 is fixed at 1 (0dB) when the internal feedback
resistor is used.
Use of this internal feedback resistor can be selected by mask option.
When "Use" is selected:
Fig. 4.15.2.1 Circuit configuration when the internal feedback resistor is used
The gain is fixed at 1 (0dB). Leave the FB terminal open.
When "Not use" is selected (example of differential input):
Fig. 4.15.2.2 Circuit configuration when the internal feedback resistor is not used (example of differential input)
The gain of the amplifier can be changed with external resistors.
A 500 k resistor is recommended for R
The gain can be found with the following formula.
R R
5 6
G = =
Amp
R R
1 2
When "Not use" is selected (example of single-end input):
Fig. 4.15.2.3 Circuit configuration when the internal feedback resistor is not used (example of single-end input)
The gain of the amplifier can be changed with external resistors.
A resistor of approximately 500 k is recommended for R
The gain can be found with the following formula.
R
F
G =
Amp
R
IN
138
FB
40k
100k
TIP
100k
RING
100k
V
REF
R
4
500pF
R
2
500pF R
1
R
3
V
REF
, R , R
1 2 5
(In case of R = R , R = R
1 2 3
R
500pF
R
IN
V
REF
EPSON
V
REF
100k
–
Amp
+
40k
V
REF
FB
R
6
TIP
–
Amp
RING
+
R
5
and R , and approximately 200 k for R
6
, R = R )
4 5 6
FB
F
TIP
–
Amp
RING
+
and R .
IN F
and R .
3 4
S1C63558 TECHNICAL MANUAL