ROHM BA6110FS Datasheet

BA6110FS

Standard ICs

Voltage controlled operational amplifier

BA6110FS

The BA6110FS is a low-noise, low-offset programmable operational amplifier. Offering superb linearity over a broad range, this IC is designed so that the forward direction conductivity (g such as voltage control amplifiers (VCA), voltage control filters (VCF) and voltage control oscillators (VCO). Distortion reduction circuitry improves the signal-to-noise ratio by a significant 10dB at a distortion rate of 0.5% in comparison with products not equipped with this feature. When used as a voltage control amplifier (VCA), a high S / N ratio of 86dB can be achieved at a distortion rate of 0.5%. The open loop gain is determined by the control current and an attached gain determining resistance R range of settings. In addition, a built-in low-impedance output buffer circuit reduces the number of attachments.

Applications

Electronic volume controls Voltage-controlled impedances Voltage-controlled amplifiers (VCA) Voltage-controlled filters (VCF) Voltage-controlled oscillators (VCO) Multipliers Sample holds Schmitt triggers

) can be changed, making it ideal for applications

, enabling a wide

Features

1) Low distortion rate. (built-in distortion reduction bias diode)

2) Low noise.

3) Low offset voltage. (V

Block diagram

!!!!

= 3m V

Max

BA6110FS

4) Built-in output buffer.

5) Variable g

with superb linearity across three decade

fields.

N.C.

16 15 14 13 12 11 10

–

12345678

N.C.

POSITIVE INPUT

N.C.

BUFFER OUTPUT

1 / 2

N.C.

NEGATIVE INPUT

BUFFER INPUT

VCA OUTPUT

N.C.

INPUT BIAS

N.C.

– V

BUFFER

N.C.

CONTROL INPUT

Standard ICs

Internal circuit configuration

!!!!

Topr Tstg

C Max.

Current mirror (2)

Current mirror (3)

Control pin

300

– 20 ~ + 70

– 55 ~ + 125

Q10Q

Fig.1

34 V

∗

Current mirror (1)

Input bias

(Ta = 25°C)

Positive input

Negative input

Absolute maximum ratings

!!!!

Parameter Symbol Limits Unit

Power supply voltage V Power dissipation Operating temperature ˚C

Storage temperature ˚C Maximum control current 500 µAI

1 Reduced by 3mW for each increase in Ta of 1˚C each 25˚C.

OUT

Current mirror (4)

Current mirror (5)

Buffer IN

BA6110FS

Buffer OUT

Electrical characteristics

!!!!

Parameter Symbol Min. Typ. Max. Unit Conditions

Quiescent current I Pin 7 bias current I Distortion THD — 0.2 1 % Fig.2 Forward transmission conductance g Pin 6 maximum output voltage | V Pin 8 maximum output voltage 911— VR Pin 6 maximum output current 300 500 650 µAI

Residual noise 1 VN

Residual noise 2 VN

Discontinuous noise VNP

Leakage level —– 94 – 75 dBm

(unless otherwise noted, Ta = 25°C, VCC = 15V, VEE = – 15V)

7PIN

OM6

OM8

| V

OM6

| I

L (Leak)

0.9 3.0 6.0 mA I — 0.8 5 µA — Fig.2

4800 8000 12000 µsI

12 14 — VI

| |

—– 94 – 90 dBm Fig.2

—– 74 – 66 dBm Fig.2

— 10.5 11.5 dB Fig.2

CONTROL

= 0µA Fig.2

CONTROL

= 200µA, VI = 5mVrms

CONTROL

= 500µA Fig.2

CONTROL

= 500µA Fig.2

= 47kΩ Fig.2

CONTROL

= 500µA Fig.2

CONTROL

= 0µA, BPF

I (30 ~ 320kHz, 3dB, 6dB / OCT)

CONTROL

= 200µA, BPF

I (30 ~ 20kHz, 3dB, 6dB / OCT)

CONTROL

= 200µA, BPF

I (30 ~ 20kHz, 3dB, 6dB / OCT)

CONTROL

= 0µA, VIN = – 30dBm

= 20kHz

Measurement

circuit

Fig.2

Standard ICs

Measurement circuit

!!!!

BA6110FS

D.V

27kΩ

Circuit discription

!!!!

10µF

600Ω

1kΩ

1 2

1kΩ

500µA→

BA6110FS

200µA→

The BA6110FS is configured of an operational amplifier which can control the forward propagation conductance

) using the control current, an input biascompensating 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 Q operational amplifier, while transistors Q

and Q14 form the differential input for the

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 V point, then 1 / 2 Ic is supplied to the Q

= 0 at this

and Q 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.

150kΩ

Fig.2

30 ~ 20kHz

BPF

47kΩ

VEE = – 10V

6-1

6-2

40dB AMP

= + 10V

V.V

THD

Vmp

For the open loop gain of this operational amplifier, if the Pin 7 control current is I resistance is R

, then:

Av = gm · RO =

CONTROL

and the Pin 11 external

CONTROL

× R

To eliminate the distortion created by the differential input, the input bias diode and its bias circuit consist of the following: bias diodes D

and D2, current mirrors (1) and (2), and the Pin 5 bias pin current mirror that consists of the transistors Q

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, Q

. The VF difference created by the emitter follower is

, and its active load,

eliminated by the emitter follower which consists of the

PNP transistor Q

and resistor R5. Also, the gain is

determined by the ratio of the signal source resistance

and the diode impedance.

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