A2

R

L

INA193A

OUT

R

S

A1

0.1 F

m

Load

V+

I

L

R

1

R

2

V

IN+

V

IN+

V

IN-

-16 V to 80 V

Negative

and

Positive

Common-Mode

Voltage

V+

3 V

>

INA193A-EP

www.ti.com

SBOS400A – MAY 2007 – REVISED SEPTEMBER 2013

Shutdown

Because the INA193A consumes a quiescent current less than 1 mA, it 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 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 Example Shutdown Circuit

Selecting RS

The value chosen for the shunt resistor, RS, depends on the application and is a compromise between small-

signal accuracy and maximum permissible voltage loss in the measurement line. High values of RS provide better

accuracy at lower currents by minimizing the effects of offset, while low values of RS minimize voltage loss in the

supply line. For most applications, best performance is attained with an RS value that provides a full-scale shunt

voltage range of 50 mV to 100 mV. Maximum input voltage for accurate measurements is 500 mV.

Transient Protection

The –16 V to 80 V common-mode range of the INA193A 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 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 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– 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 inputs with two equal resistors on each input).

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