2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

0

2

4

6

8

10

12

14

16

18

V

(mV)

SENSE

20

Actual

Ideal

19

INA193, INA194, INA195

INA196, INA197, INA198

www.ti.com

SBOS307G – MAY 2004 – REVISED JANUARY 2015

Product Folder Links: INA193 INA194 INA195 INA196 INA197 INA198

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Copyright © 2004–2015, Texas Instruments Incorporated

Device Functional Modes (continued)

8.4.2.3 Low VSENSE Case 1: VSENSE < 20mV, −16v ≤ VCM < 0; and Low VSENSE Case 3: VSENSE < 20mV, VS <

VCM ≤ 80V

Although the INA193

−INA198 family of devices are not designed for accurate operation in either of these

regions, some applications are exposed to these conditions; for example, when monitoring power supplies that

are switched on and off while VS is still applied to the INA193−INA198 devices. It is important to know what the

behavior of the devices will be in these regions.

As VSENSE approaches 0 mV, in these VCM regions, the device output accuracy degrades. A larger-than-normal

offset can appear at the current shunt monitor output with a typical maximum value of VOUT = 300 mV for VSENSE

= 0 mV. As VSENSE approaches 20 mV, VOUT returns to the expected output value with accuracy as specified in

the Electrical Characteristics. Figure 26 illustrates this effect using the INA195 and INA198 devices (Gain = 100).

Figure 26. Example for Low VSENSE Cases 1 and 3 (INA195, INA198: Gain = 100)

8.4.2.4 Low VSENSE Case 2: VSENSE < 20 mV, 0 V ≤ VCM ≤ VS

This region of operation is the least accurate for the INA193

−INA198 family of devices. To achieve the wide input

common-mode voltage range, these devices use two op amp front ends in parallel. One op amp front end

operates in the positive input common-mode voltage range, and the other in the negative input region. For this

case, neither of these two internal amplifiers dominates and overall loop gain is very low. Within this region, VOUT

approaches voltages close to linear operation levels for Normal Case 2. This deviation from linear operation

becomes greatest the closer VSENSE approaches 0 V. Within this region, as VSENSE approaches 20 mV, device

operation is closer to that described by Normal Case 2. Figure 27 illustrates this behavior for the INA195 device.

The VOUT maximum peak for this case is tested by maintaining a constant VS, setting VSENSE = 0 mV and

sweeping VCM from 0 V to VS. The exact VCM at which VOUT peaks during this test varies from part to part, but the

VOUT maximum peak is tested to be less than the specified VOUT Tested Limit.