ROHM BA3131

BA3131FS
Standard ICs
Dual operational amplifier with switch,
for audio use (3 inputs × 1 output × 2)
BA3131FS
The BA3131FS contains two built-in circuits with operational amplifiers configured of three differential input circuits, an
output circuit, and a switch circuit. The three differential input circuits are separate, enabling independent settings to be
entered for the gain and frequency characteristics.
!Applications
Car stereos, audio amplifiers and other electronic circuits
!Features
1) High gain and low distortion. (Gv = 110dB, THD = 0.0015% typ.)
2) Low noise. (Vn = 2µVrms typ.)
3) Switching circuit can be directly coupled to microcomputer port.
4) Small switching noise.
5) Equipped with 1 / 2 Vcc output circuit for single power supply.
!Block diagram
+ IN1A
1
- IN1A
2
20 + IN2A
19 - IN2A
– +
+ IN1B
3
- IN1B
4
+–
18 + IN2B
17 - IN2B
+–
– +
+ IN1C
5
- IN1C
6
16 + IN2C
15 - IN2C
+–
– +
OUT1
14 OUT2
7
3
SW1
3
13 Vref OUT
8
+
SW2
–
12 1 / 2 VCC
9
GND 10
11 VCC
R
R
BA3131FS
Standard ICs
!Absolute maximum ratings (Ta=25°C)
Parameter
Symbol
Limits
Power supply voltage
VCC
18.0
V
Power dissipation
Pd
750∗
mW
Operating temperature
Topr
– 40 ~ + 85
˚C
Storage temperature
Tstg
– 55 ~ + 125
˚C
Vi
3 ~ VCC
V
Common-mode input voltage
Differential input voltage
Vid
VCC
Load current
IoMax.
± 50.0
Unit
V
mA
∗ Reduced by 7.5mW for each increase in Ta of 1˚C
over 25˚C.
(When mounted on a glass epoxy board (90mm × 50mm × 1.6t))
!Recommended operating conditions (Ta=25°C)
Parameter
Operating power supply voltage
Symbol Min.
Typ.
Max.
Unit
Conditions
6.0
8.0
16.0
V
single power source
VCC
!Electrical characteristics (unless otherwise noted, Ta=25°C, Vcc=8V)
Parameter
Min.
Typ.
Max.
Unit
Quiescent current
Iq
2.0
4.9
7.8
mA
VIN = 0, RL = ∞ , SW pin open
Fig.2
Input offset voltage
Vio
-
0.5
5.0
mV
RS ≤ 10kΩ
Fig.1
Input offset current
Iio
-
5
200
nA
Input bias current
Ib
-
50
500
nA
∗1
Fig.1
High-amplitude voltage gain
Avol
86
110
-
dB
RL ≥ 2kΩ, VO = ± 1.5V
Fig.1
Common-mode input voltage
Vicm
3
6
-
V
In-phase signal rejection ratio
CMRR
60
72
-
dB
RS ≤ 10kΩ
Fig.1
Power supply voltage rejection ratio
PSRR
76
90
-
dB
RS ≤ 10kΩ
Fig.1
Maximum output voltage
VOH
/
VOL
3
6
-
V
RL ≥ 10kΩ
3
6
-
V
RL ≥ 2kΩ
Fig.3
/
Fig.4
Input conversion noise voltage
Vn
-
2.0
4.0
µVrms
∗2
Fig.7
∆VREF
-
-
Reference voltage change
± 10
mV
Conditions
Measurement
circuit
Symbol
Fig.1
Fig.1
Ioref = ± 1mA
-
∗1 Because the first stage is contigured with PNP transistors, input bias current is from the IC.
∗2 Tested under the following conditions: GV = 40dB, RS = 2kΩ, Matsushita Tsuko VP-9690A (using DIN audio filter)
!Design guaranteed values (unless otherwise noted, Ta=25°C, Vcc=8V)
Parameter
Min.
Typ.
Max.
SR
0.5
1.2
-
Gainbandwidth product
GBW
1.5
2.6
-
MHz
f = 10kHz
Fig.6
Crosstalk between A, B and C
CTABC
60
73
-
dB
f = 1kHz
Fig.8
Total harmonic distortion
THD
-
%
GV = 0dB, f = 1kHz, VO = 1Vrms
Fig.9
CS
90
dB
f = 1kHz, input conversion
Fig.10
Slew rate
Channel separation
∗ This item is not guaranteed during processes.
0.0025 0.01
115
-
Unit
Conditions
Measurement
circuit
Symbol
V / µS GV = 0dB, RL = 2kΩ
Fig.5
BA3131FS
Standard ICs
!Measurement circuit
C2
0.1µF
RK
50kΩ
RK
500kΩ
C1
EK
0.1µF
S1
VCC
Rs
Ri
50Ω
10kΩ
VO
15V
RK
500kΩ
+
–
NULL
DUT
–
VF
+
Rs
Ri
50Ω
10kΩ
S3
C3
1000pF
S4
– 15V
S2
Rf
50kΩ
VR
RL2
10kΩ
RL1
2kΩ
Vref
Vref
Vref
∗ C2 and C3 are used to prevent oscillation (adjustment required)
Fig.1
BA3131FS
Standard ICs
!Measurement conditions (Figure 1)
VCC
VR
EK
VF
S1
S2
Input offset voltage
8
Vref
—
VF1
ON
ON
OFF OFF
1
Input offset current
8
Vref
—
VF2
OFF OFF OFF OFF
2
VF3
OFF
ON
VF4
ON
OFF
ON
Measurement Item
Input bias current
8
Vref
High-amplitude voltage gain
8
Vref
Common-mode signal rejection ratio
(Common-mode input voltage)
8
8
Power supply voltage
rejection ratio
—
5.5
VF5
2.5
VF6
6
8
VF7
2
0
VF8
6
Vref
—
VF9
18
Vref
—
VF10
!Equations
(1) Input offset voltage (Vio)
Vio = | VF1 | / (1 + Rf / Rs)
(2) Input offset current (Iio)
Iio = | VF2 - VF1 | / (Ri (1 + Rf / Rs) )
(3) Input bias current (Ib)
Ib = | VF4 - VF3 | / (2 Ri (1 + Rf / Rs) )
(4) High-amplitude voltage gain (Avol)
Avol = 20log (3 (1 + Rf / Rs) / | VF6 - VF5 | ) (dB)
(5) In-phase signal rejection ratio (CMRR)
CMRR = 20log (4 (1 + Rf / Rs) / | VF8 - VF7 | ) (dB)
(6) (In-phase input voltage range) (PSRR)
PSRR = 20log (12 (1 + Rf / Rs) / | VF10 - VF9 | ) (dB)
S3
S4
Equation
OFF OFF
3
ON
ON
OFF
4
ON
ON
OFF OFF
5
ON
ON
OFF OFF
6
BA3131FS
Standard ICs
!Measurement circuits
Vcc
Iq
Vcc
A
+
–
+
2k
or
10kΩ
–
1V
Vref
Vref
Vref
V
VoH
Vref
Fig. 3 Maximum output voltage: High
Fig.2 Iq
Vcc = 18V
Vcc
+
–
1V
Vref
Vref
2k
or
10kΩ
–
VOUT
V
VoL
+
VIN
RL
2kΩ
Vref
Vref
Fig. 4 Maximum output voltage: Low
Fig. 5 Slew rate ( )
Vout (V)
15
Vcc
t (µsec)
10kΩ
0.1µF
–
10µF
+
V
VIN
f = 10kHz
5
t
SR = 10 / t
Fig. 6 Slew rate ( )
Vref
GB = Vo / VIN × f
Fig. 7 Band width frequency gain
Vo
BA3131FS
Standard ICs
100kΩ
–
A
1kΩ / 100kΩ
1kΩ
+
100kΩ
Vcc
3.3µF
0.47µF
B.P.F
20Hz ~ 30kHz
+
–
2.2kΩ 56kΩ
Vref
Von
1kΩ / 100kΩ
Vref
–
B
Vo
+
100kΩ
1kΩ
100kΩ
–
C
Vref
Vref
100kΩ
+
1kΩ
CTABC = 20log
1kΩ / 100kΩ
1k
Vn =
47µF
Vcc = 8V
Von
3
100 × 10
1÷
1 × 103
Vref
~
VIN
f = 1kHz
Channel selection
Vref
Fig. 8 Input conversion noise voltage
Vo
Vcc
3.3µF
0.47µF
+
56kΩ
100kΩ
Distortion meter
–
2.2kΩ
VIN
f = 1kHz
Fig. 9 Crosstalk between A and B
100kΩ
–
Vo1
+
~
Vref
1kΩ
CH-1
1kΩ
Vref
1k / 100kΩ
Vo = 1Vrms
Vref
Fig. 10 Total harmonic distortion
100kΩ
1kΩ
–
Vo2
+
~
Vref
CH-2
f = 1kHz
1k / 100kΩ
Vref
CS = 20log
Vo1
100Vo2
Vcc = 8V
Fig. 12 Channel separation ( )
Vref
Fig. 11 Channel separation ( )
VoA or VoB
VoC
BA3131FS
Standard ICs
!Application example
R2
47k
R8
1k
R4
47k
R10
1k
R6
47k
Aamp: Gv = 20dB
Bamp: Gv = 10dB
Camp: Gv = 0dB
R12
1k
3.3µ
IN2C
C6
3.3µ
IN2B
C5
IN2A
R16
3.3µ
OUT2
10k
R14
C4
3.3k
Vcc = 8V
20
19
18
17
16
15
14
13
12
11
C7
BA3131FS
1
2
3
4
5
100µ
6
7
8
9
C9
C10
0.022µ 22µ
C8
100µ
10
R13
3.3k
3.3µ
R15
IN1A
OUT1
C3
IN1B
C2
IN1C
10k
3.3µ
3.3µ
C1
R1
47k
R7
1k
R3
47k
R9
1k
R5
47k
R11
1k
SW1
SW2
µCOM.
Fig.13
BA3131FS
Standard ICs
!Operation notes
(1) Pin 13 is the reference output pin, from which 1 / 2 Vcc is output. The value for the bypass capacitor should be
determined based on the desired characteristics. A value between 500pF and 1µF may produce oscillation, so if AC
grounding is being used, always use a bypass capacitor with a value of at least 10µF.
Also, Pin 12 is designated for reference circuit input, so if reference output is being used, always use a bypass capacitor
for AC grounding. (We recommend a bypass capacitor with a value of 22µF.)
•Reference data (these values are intended only as a reference, and performance is not guaranteed)
Pin 12 bypass capacitor (µF)
Ripple rejection ratio (fIN = 100 Hz) (dB)
Output rise time (ms)∗
10
– 35
150
22
– 42
300
47
– 48
550
∗ Test conditions: When power supply is on (VCC = 8V), time equal to 90% of VCC bypass capacitor,Pin 13 bypass
capacitor 100µF, output smoothing voltage.
(2) This IC offers stability even at low gain (0 to 20dB), but a capacitance load of 200pF or higher may cause oscillation
(the phase margin at a capacitance of 200pF is 10° typ. (Ta = 85°C, 0dB point) ). Consequently, please make sure
sufficient care is taken in terms of the capacitance load.
When using a 0dB buffer, as shown in the application example (Figure 13), introducing a bias resistance of several kΩ to
the negative input (R11 and R12 in Figure 13, indicated as circled items) results in greater stability in terms of the
capacitance load.
!Truth value table
ch1
ch2
ch3
OFF
Conditions
SW1 (8pin)
H
H
L
L
SW2 (9pin)
H
L
H
L
Corresponds to
µCOM output
∗ “H” when the applied voltage at pins 8 and 9 is 2.0V or more, and “L” when it is 1.0V or less.
BA3131FS
Standard ICs
!Electrical characteristic curves
120
1
Vcc = 8V
Gv = 0dB
Vo = 1Vrms
0.1
110
CTABC
0.05
0.01
90
C.S.
80
70
60
0.005
Vcc = 8V
Gv = 0dB
Vo = 1Vrms
50
0.00
20
50 100
500 1k
40
20
5k 10k 20k
FREQUENCY: f (Hz)
REFERENCE VOLTAGE :Vref (V)
Vcc = 8V
SINK
4.0
SOURCE
3.9
10
13pin OUTPUT CURRENT: ∆IOUT (mA)
Fig. 17 Reference voltage vs.
pin 13 output current
!External dimensions (Units: mm)
1
10
5.4 ± 0.2
11
0.8
0.15 ± 0.1
1.8 ± 0.1
0.11
7.8 ± 0.3
8.7 ± 0.2
20
0.36 ± 0.1
5k 10k 20k
Fig. 15 Channel separation and
crosstalk vs. frequency
4.1
5
500 1k
FREQUENCY: f (Hz)
Fig. 14 Distortion vs. frequency
0
50 100
0.3Min.
0.15
SSOP-A20
DISTN (THD + Vn) (%)
0.1
VCC = 8V
GV = 0dB
0.05
100
C.S., CTABC (dB)
DISTN (THD + Vn) (%)
0.5
0.01
fIN = 10kHz
1kHz
100Hz
0.005
0.001
0.05
0.1
0.5
1.0
OUTPUT VOLTAGE: Vo (Vrms)
Fig. 16 Distortion vs. output voltage