BA6110 데이터 시트보기 (PDF) - ROHM Semiconductor
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BA6110 Datasheet PDF : 7 Pages
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Standard ICs
!Measurement circuit
BA6110FS
D.V
S4
27kΩ
1kΩ
10µF
+
1 S1
2
1
S5
11
12
15
V
BA6110FS
600Ω
14
3
1kΩ
5
9
S3 7
S7
2
1
3
S2
1
3
2
2 150kΩ
1
1V
mA
VCC = + 10V
S0
47kΩ
1 30 ~ 20kHz
BPF
2
S6-1
1 S6-2
2
V.V THD DV
VEE = – 10V
40dB AMP
Vmp
Fig.2
!Circuit discription
The BA6110FS is configured of an operational amplifier
which can control the forward propagation conductance
(gm) using the control current, an input bias-
compensating diode used to eliminate distortion created
by the amplifier’s differential input, a bias setter, and an
output buffer.
In the operational amplifier, Pin 1 is the positive input and
Pin 3 is the negative input. Pin 7 is the control pin which
determines the differential current. Pin 11 is the output pin
which determines the open loop gain using the external
resistor and the control current.
This section describes the circuit operation of this
operational amplifier.
Transistors Q13 and Q14 form the differential input for the
operational amplifier, while transistors Q7 to Q12 are
composed of the current mirror circuits. The current
mirror absorbs current from the differential input common
emitter which is equal to the control current flowing into
the Pin 7 control pin. If the differential input VIN = 0 at this
point, then 1 / 2 Ic is supplied to the Q13 and Q14
collectors and the other half passes through the current
mirrors (3) and (4). The output of current mirror (3) which
is the differential active load is inverted by current mirror
(5), and is balanced with the output of current mirror (4),
also an active load.
If the differential input changes, the current balance
changes. The output current is on Pin 11. An output
voltage can be generated using an external resistance.
For the open loop gain of this operational amplifier, if the
Pin 7 control current is ICONTROL and the Pin 11 external
resistance is RO, then:
Av = gm · RO =
ICONTROL × RO
2
KT
q
To eliminate the distortion created by the differential input,
the input bias diode and its bias circuit consist of the
following: bias diodes D1 and D2, current mirrors (1) and
(2), and the Pin 5 bias pin current mirror that consists of
the transistors Q1 to Q6 and the resistance R1.
This circuit eliminates the distortion that occurs as a
result of using the differential input open loop.
In the buffer circuit, Pin 12 is the buffer input and Pin 14 is
the buffer output.
In the buffer circuit, the emitter follower consists of the
active load of the NPN transistor, Q17, and its active load,
Q16. The VF difference created by the emitter follower is
eliminated by the emitter follower which consists of the
PNP transistor Q18 and resistor R5. Also, the gain is
determined by the ratio of the signal source resistance
RIN and the diode impedance.
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