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Shutdown

A2

R

L

INA193A INA198A

-

OUT

R

S

A1

0.1 F

m

Load

V+

I

L

R

1

R

2

V

IN+

V

IN+

V

IN-

-16Vto80V

Negative

and

Positive

Common-Mode

Voltage

V+

3V

>

Selecting R

S

Transient Protection

INA193A-EP,, INA194A-EP,, INA195A-EP

INA196A-EP, INA197A-EP, INA198A-EP

SBOS400 – MAY 2007

APPLICATION INFORMATION (continued)

Because the INA193A–INA198A consume a quiescent current less than 1 mA, they can be powered by either

the output of logic gates or by transistor switches to supply power. Use a totem pole output buffer or gate that

can provide sufficient drive along with 0.1

µF bypass capacitor, preferably ceramic with good high frequency

characteristics. This gate should have a supply voltage of 3 V or greater because the INA193A–INA198A

requires a minimum supply greater than 2.7 V. In addition to eliminating quiescent current, this gate also turns

off the 10

µA bias current present at each of the inputs. An example shutdown circuit is shown in Figure 4.

Figure 4. INA193A–INA198A Example Shutdown Circuit

provides a full-scale shunt voltage range of 50 mV to 100 mV. Maximum input voltage for accurate

measurements is 500 mV.

The –16 V to 80 V common-mode range of the INA193A–INA198A is ideal for withstanding automotive fault

conditions ranging from 12 V battery reversal up to 80 V transients, since no additional protective components

are needed up to those levels. In the event that the INA193A–INA198A is exposed to transients on the inputs in

excess of its ratings, then external transient absorption with semiconductor transient absorbers (zeners or

Transzorbs) will be necessary. Use of MOVs or VDRs is not recommended except when they are used in

addition to a semiconductor transient absorber. Select the transient absorber such that it will never allow the

INA193A–INA198A to be exposed to transients greater than 80 V (that is, allow for transient absorber tolerance,

as well as additional voltage due to transient absorber dynamic impedance). Despite the use of internal zener

type ESD protection, the INA193A–INA198A does not lend itself to using external resistors in series with the

inputs since the internal gain resistors can vary up to

±30%. (If gain accuracy is not important, then resistors can

be added in series with the INA193A–INA198A inputs with two equal resistors on each input.)

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