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
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
33
RR
GND
SW2
OUT1
- IN1C
+ IN1C
+ IN1B
- IN1B
+ IN1A
- IN1A
SW1
V
CC
1 / 2 V
CC
OUT2
- IN2C
+ IN2C
+ IN2B
- IN2B
+ IN2A
- IN2A
Vref OUT
–++–
–+
+–
–+
+–
+
–
BA3131FS
Standard ICs
!
!!
!Absolute maximum ratings (Ta=25°C)
Parameter Symbol Limits Unit
Power supply voltage V
Power dissipation 750∗mW
Operating temperature Topr ˚C
Storage temperature Tstg ˚C
Common-mode input voltage V
Differential input voltage V
Load current ± 50.0 mA
∗
Reduced by 7.5mW for each increase in Ta of 1˚C over 25˚C.
VCC
3 ~ VCC
VCC
Vi
Vid
18.0
Pd
IoMax.
– 40 ~ + 85
– 55 ~ + 125
(When mounted on a glass epoxy board (90mm × 50mm × 1.6t))
!
!!
!Recommended operating conditions (Ta=25°C)
Parameter Symbol Min. Typ. Max. Unit Conditions
Operating power supply voltage VCC 6.0 8.0 16.0 V single power source
!
!!
!Electrical characteristics (unless otherwise noted, Ta=25°C, Vcc=8V)
Parameter Symbol Min. Typ. Max. Unit Conditions
Quiescent current 2.0 4.9 7.8 mA
Input offset voltage - 0.5 5.0 mV
Input offset current - 5 200 nA
Input bias current - 50 500 nA
High-amplitude voltage gain 86 110 - dB
Common-mode input voltage 36-V
In-phase signal rejection ratio CMRR 60 72 - dB
Power supply voltage rejection ratio PSRR 76 90 - dB
Maximum output voltage /
VOH
VOL
36-V /
36-V
Input conversion noise voltage - 2.0 4.0 µVrms
Reference voltage change - - ± 10 mV -
Iq
Vio
Iio
Ib
Vicm
Vn
RS ≤ 10kΩ
RL ≥ 2kΩ, VO = ± 1.5V
RS ≤ 10kΩ
RS ≤ 10kΩ
RL ≥ 10kΩ
Ioref = ± 1mA
Fig.2
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.3
Fig.4
Fig.7
Avol
RL ≥ 2kΩ
∗
2
∗
1
VIN = 0, RL = ∞ , SW pin open
Measurement
circuit
∆VREF
∗1 Because the first stage is contigured with PNP transistors, input bias current is from the IC.
∗2 Tested under the following conditions: G
V
=
40dB, RS = 2kΩ, Matsushita Tsuko VP-9690A (using DIN audio filter)
!
!!
!Design guaranteed values (unless otherwise noted, Ta=25°C, Vcc=8V)
Slew rate SR 0.5 1.2 - V / µS
Gainbandwidth product GBW 1.5 2.6 - MHz f = 10kHz
Crosstalk between A, B and C CT
ABC
60 73 - dB f = 1kHz
THD - 0.0025 0.01 %
CS 90 115 - dB
Parameter Symbol Min. Typ. Max. Unit Conditions
Fig.5
Fig.6
Fig.8
Fig.9
Fig.10
Channel separation
∗ This item is not guaranteed during processes.
Total harmonic distortion
Measurement
circuit
f = 1kHz, input conversion
G
V
= 0dB, f = 1kHz, V
O
= 1Vrms
G
V
= 0dB, RL = 2kΩ
BA3131FS
Standard ICs
!
!!
!Measurement circuit
RK
RK
50kΩ
500kΩ
RK
500kΩ
0.1µF
C2
0.1µF
1000pF
C1
C3
15V
EK
VF
– 15V
–
+
+
–
DUT NULL
V
CC
V
O
S1
Ri
Ri
10kΩ
Rs
50Ω
10kΩ
Rs
50Ω
Vref
Vref
VR Vref
RL2
10kΩ
RL1
2kΩ
S3
S2
S4
Rf
50kΩ
∗ C2 and C3 are used to prevent oscillation (adjustment required)
Fig.1
BA3131FS
Standard ICs
!
!!
!Measurement conditions (Figure 1)
Measurement Item EK Equation
Input offset voltage 8—ON ON OFF OFF 1
Input offset current 8—OFF OFF OFF OFF 2
Input bias current 8—OFF ON OFF OFF 3
ON OFF
High-amplitude voltage gain 85.5 ON ON ON OFF 4
2.5
868 ON ON OFF OFF 5
820
Power supply voltage
rejection ratio 6—ON ON OFF OFF 6
18 —
Common-mode signal rejection ratio
(Common-mode input voltage)
VCC VR
Vref
Vref
Vref
Vref
Vref
Vref
VF1
VF
VF2
VF3
VF4
VF5
VF6
VF7
VF8
VF9
VF10
S1 S2 S3 S4
!
!!
!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)
BA3131FS
Standard ICs
!
!!
!Measurement circuits
Vref
–
+
A
Vcc
Iq
Fig.2 Iq
Vref
+
–
Vref Vref
V
Vcc
1V
2k
or
10kΩVoH
Fig. 3 Maximum output voltage: High
Vref
+
–
Vref Vref
V
Vcc
1V 2k
or
10kΩVoL
Fig. 4 Maximum output voltage: Low
–
+
V
IN
Vref
Vcc = 18V
RL
2kΩ
V
OUT
Fig. 5 Slew rate ( )
t (µsec)
15
5
Vout (V)
t
SR = 10 / t
Fig. 6 Slew rate ( )
+
–
Vref
V
Vcc
Vo
10kΩ
10µF
GB = Vo / V
IN
× f
0.1µF
V
IN
f = 10kHz
Fig. 7 Band width frequency gain
BA3131FS
Standard ICs
+
–
Vref
Vref
Vcc
100kΩ
0.47µF
3.3µF
1k
47µF
2.2kΩ56kΩ100kΩ
B.P.F
20Hz ~ 30kHz Von
Vn = Von
1 ÷100 × 10
1 × 103
3
Fig. 8 Input conversion noise voltage
–
+
C
–
+
B
–
+
A
Vref
Vref
Vref
Vref
Channel selection
100kΩ
100kΩ
100kΩ
1kΩ / 100kΩ
1kΩ / 100kΩ
1kΩ / 100kΩ
1kΩ
1kΩ
1kΩ
V
IN
f = 1kHz
CT
ABC
= 20log VoC
VoA or VoB
Vcc = 8V
Vo
Fig. 9 Crosstalk between A and B
~
Vref
Vref
100kΩ
1kΩ
V
IN
f = 1kHz
–
+
Distortion meter
Vo = 1Vrms
Vo
0.47µF
Vcc
2.2kΩ
56kΩ
3.3µF
Fig. 10 Total harmonic distortion
~
VrefVref
100kΩ
1k / 100kΩ
1kΩ
–
+Vo1
CH-1
Fig. 11 Channel separation ( )
VrefVref
100kΩ
1k / 100kΩ
1kΩ
f = 1kHz
–
+
Vo2
CH-2
Vcc = 8V
CS = 20log Vo1
100Vo2
Fig. 12 Channel separation ( )
~
BA3131FS
Standard ICs
!
!!
!Application example
20
1
19
2
18
3
17
4
16
5
15
6
14
7
13
8
12
9
11
10
Aamp: Gv = 20dB
Bamp: Gv = 10dB
Camp: Gv = 0dB
OUT2
Vcc = 8V
C7 C8 C9 C10
100µ0.022µ22µ100µ
BA3131FS
R14
R16
R12
1k
R6
47k
R10
1k
R4
47k
R8
1k
R2
47k
R5
R15
R11
47k
R9
1k 1k
R3
47k
R7
1k
R1
47k
10k
R13
3.3k
10k
3.3k
3.3µ
3.3µ
3.3µ
C6
C5
C4
IN2C
IN2B
IN2A
3.3µ
C3
C2
C1
IN1A
IN1B
IN1C
3.3µ
3.3µ
SW1 SW2
µCOM.
OUT1
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)
10 – 35 150
22 – 42 300
47 – 48 550
Ripple rejection ratio (f
IN
= 100 Hz) (dB)Pin 12 bypass capacitor (µF) Output rise time (ms)∗
∗ Test conditions: When power supply is on (V
CC
= 8V), time equal to 90% of V
CC
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
H
HCorresponds to
µCOM output
ch1 Conditions
∗
“H” when the applied voltage at pins 8 and 9 is 2.0V or more, and “L” when it is 1.0V or less.
SW1 (8pin)
SW2 (9pin)
H
L
ch2
L
H
ch3
L
L
OFF
BA3131FS
Standard ICs
!
!!
!Electrical characteristic curves
DISTN (THD + Vn) (%)
FREQUENCY: f (Hz)
0.005
0.01
0.05
0.1
0.5
1
20 50 100 500 1k 5k 10k 20k
Vcc = 8V
Gv = 0dB
Vo = 1Vrms
0.00
Fig. 14 Distortion vs. frequency
C.S., CT
ABC
(dB)
FREQUENCY: f (Hz)
20 50 100 500 1k 5k 20k10k
120
110
100
90
80
70
60
50
40
Vcc = 8V
Gv = 0dB
Vo = 1Vrms
CT
ABC
C.S.
Fig. 15 Channel separation and
crosstalk vs. frequency
DISTN (THD + Vn) (%)
OUTPUT VOLTAGE: Vo (Vrms)
0.001
0.005
0.01
0.05 0.1 0.5 1.0
0.05
0.1 V
CC
= 8V
G
V
= 0dB
f
IN =
10kHz
1kHz
100Hz
Fig. 16 Distortion vs. output voltage
REFERENCE VOLTAGE :Vref (V)
13pin OUTPUT CURRENT: ∆IOUT (mA)
Vcc = 8V
SINK
SOURCE
4.1
4.0
3.9
0510
Fig. 17 Reference voltage vs.
pin 13 output current
!
!!
!External dimensions (Units: mm)
SSOP-A20
11
10
20
1
0.11
7.8 ± 0.3
5.4 ± 0.2
8.7 ± 0.2
0.15 ± 0.1
0.36 ± 0.10.8
1.8 ± 0.1
0.3Min.
0.15
Appendix
Appendix1-Rev1.0
The products listed in this document are designed to be used with ordinary electronic equipment or devices
(such as audio visual equipment, office-automation equipment, communications devices, electrical
appliances and electronic toys).
Should you intend to use these products with equipment or devices which require an extremely high level of
reliability and the malfunction of with would directly endanger human life (such as medical instruments,
transportation equipment, aerospace machinery, nuclear-reactor controllers, fuel controllers and other
safety devices), please be sure to consult with our sales representative in advance.
Notes
No technical content pages of this document may be reproduced in any form or transmitted by any
means without prior permission of ROHM CO.,LTD.
The contents described herein are subject to change without notice. The specifications for the
product described in this document are for reference only. Upon actual use, therefore, please request
that specifications to be separately delivered.
Application circuit diagrams and circuit constants contained herein are shown as examples of standard
use and operation. Please pay careful attention to the peripheral conditions when designing circuits
and deciding upon circuit constants in the set.
Any data, including, but not limited to application circuit diagrams information, described herein
are intended only as illustrations of such devices and not as the specifications for such devices. ROHM
CO.,LTD. disclaims any warranty that any use of such devices shall be free from infringement of any
third party's intellectual property rights or other proprietary rights, and further, assumes no liability of
whatsoever nature in the event of any such infringement, or arising from or connected with or related
to the use of such devices.
Upon the sale of any such devices, other than for buyer's right to use such devices itself, resell or
otherwise dispose of the same, no express or implied right or license to practice or commercially
exploit any intellectual property rights or other proprietary rights owned or controlled by
ROHM CO., LTD. is granted to any such buyer.
Products listed in this document use silicon as a basic material.
Products listed in this document are no antiradiation design.
About Export Control Order in Japan
Products described herein are the objects of controlled goods in Annex 1 (Item 16) of Export Trade Control
Order in Japan.
In case of export from Japan, please confirm if it applies to "objective" criteria or an "informed" (by MITI clause)
on the basis of "catch all controls for Non-Proliferation of Weapons of Mass Destruction.
