®

INA2141

8

APPLICATION INFORMATION

Figure 1 shows the basic connections required for operation

of the INA2141. Applications with noisy or high impedance

power supplies may require decoupling capacitors close to

the device pins as shown.

The output is referred to the output reference (Ref) terminals

be low-impedance connections to assure good common-

mode rejection. A resistance of 8

Ω in series with a Ref pin

will cause a typical device to degrade to approximately

80dB CMR (G = 1).

The INA2141 has a separate output sense feedback connec-

respective output terminals for proper operation. The output

sense connection can be used to sense the output voltage

directly at the load for best accuracy.

SETTING THE GAIN

Gain of each IA can be independently selected with a jumper

connection as shown in Figure 1. G = 10V/V with no jumper

installed. With a jumper installed G = 100V/V. To preserve

good gain accuracy, this jumper must have low series

resistance. A resistance of 0.5

Ω in series with the jumper

will decrease the gain by 0.1%.

Internal resistor ratios are laser trimmed to assure excellent

gain accuracy. Actual resistor values can vary by approxi-

mately

±25% from the nominal values shown.

Gains between 10 and 100 can be achieved by connecting an

external resistor to the jumper pins. This is not recom-

mended, however, because the

±25% variation of internal

resistor values makes the required external resistor value

uncertain. A companion model, INA2128, features accu-

rately trimmed internal resistors so that gains from 1 to

10,000 can be set with an external resistor.

DYNAMIC PERFORMANCE

The typical performance curve “Gain vs Frequency” shows

that despite its low quiescent current, the INA2141 achieves

wide bandwidth, even at high gain. This is due to its current-

feedback topology. Settling time also remains excellent at

high gain.

NOISE PERFORMANCE

The INA2141 provides very low noise in most applications.

Low frequency noise is approximately 0.2

µVp-p measured

from 0.1 to 10Hz (G = 100). This provides dramatically

improved noise when compared to state-of-the-art chopper-

stabilized amplifiers.

FIGURE 1. Basic Connections.

A

1

A

2

A

3

6

(11)

7

Sense

(10)

(12)

(13)

(14)

(16)

(15)

40k

Ω

40k

Ω

40k

Ω

40k

Ω

9

8

2

4

3

J

J

1

Pin numbers for

Channel B shown

in parenthesis.

V

IN

V

IN

G = 10V/V

Open Circuit

G = 100V/V

Connect Jumper

V+

V–

INA2141

–

+

5

Over-Voltage

Protection

25k

Ω

25k

Ω

Over-Voltage

Protection

Load

V

+

–

0.1µF

0.1µF

NOTE: If channel is unused,

connect inputs to ground, sense

to V

+

–

V

O

Also drawn in simplified form:

INA2141

Ref

V

O

V

IN

–

V

IN

+

Ref

5050

Ω

252

Ω

252

Ω