BA6110FS

Standard ICs

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!Attached components

(1) Positive input (Pin 1)

This is the differential positive input pin. To minimize the

distortion due to the diode bias, an input resistor is

connected in series with the signal source. By increasing

the input resistance, distortion is minimized.

However, the degree of improvement for resistances

greater than 10k

Ω is about the same. An input resistance

of 1k

Ω to 20kΩ is recommended.

(2) Negative input (Pin 3)

This is the differential negative input pin. It is grounded

with roughly the same resistance value as that of the

positive input pin. The offset adjustment is also

connected to this pin. Make sure a sufficiently high

resistance is used, so as not to disturb the balance of the

input resistance (see Figure 3).

(3) Input bias diode (Pin 5)

The IC input impedance when the diode is biased, if the

(

Ω)

26

(4) Control (Pin 7)

This pin controls the differential current. By changing the

current which flows into this pin, the gain of the differential

amplifier can be changed.

(5) Output (Pin 11)

the Pin 7 control terminal, as follows:

52 (mV)

Make sure the resistor is selected based on the desired

maximum output and gain.

(6) Buffer input (Pin 12)

The buffer input consists of the PNP and NPN emitter

follower. The bias current is normally about 0.8

µA.

Consequently, when used within a small region of control

current, we recommend using the high input impedance

FET buffer.

(7) Buffer output resistance (Pin 14)

An 11k

output within the IC. When adding an external resistance

between the GND and the output, make sure the resistor

Ω.

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!Application example

(1) Fig.3 shows a voltage-controlled amplifier (AM

modulation) as an example of an application of the

BA6110FS.

52 (mV)

Good linearity can be achieved when controlling over

three decades.

input is biased at the diode and distortion is reduced.

The gain in this case is given by the diode impedance Rd

following:

×

Ω, so that the

Fig. 6 shows the control current in relation to the open

loop gain at the diode bias. In the same way, Fig.7 shows

the control current in relation to the THD = 0.5% output at

the bias point.

Fig. 8 shows a graph of the control current in relation to

the open gain with no diode bias.

Fig. 9 shows a graph of the control current in relation to

the SN ratio.

Fig. 10 shows a graph of the diode bias current in relation

to the SN ratio.

Fig. 11 shows a graph of the power supply voltage

characteristics.

(2) Fig. 4 shows a low pass filter as an example of an

application of the BA6110FS.

Pin 7 control current.

(R

This is attenuated by -6dB / OCT.

output characteristics.

(3) Fig. 5 shows a voltage-controlled secondary low

passfilter as an example of an application of the

BA6110FS.

thePin 7 control current.

(R

This is attenuated by - 12dB / OCT.

characteristic.