SLYS017D April 2018 – July 2022 INA180-Q1 , INA2180-Q1 , INA4180-Q1
PRODMIX
With a small amount of additional circuitry, the
INAx180-Q1 can be used in circuits
subject to transients higher than 26 V, such as automotive applications. Use only
Zener diodes or Zener-type transient absorbers (sometimes referred to as
transzorbs)—any other type of transient absorber has an unacceptable time
delay. Start by adding a pair of resistors as a working impedance for the Zener
diode, as shown Figure 9-5. Keep these resistors as small as possible; most often, around 10 Ω. Larger
values can be used with an effect on gain that is discussed in the Section 9.1.3 section. This circuit limits only short-term transients; therefore, many
applications are satisfied with a 10-Ω resistor along with conventional Zener diodes
of the lowest acceptable power rating. This combination uses the least amount of
board space. These diodes can be found in packages as small as
SOT-523 or SOD-523.
In the event that low-power Zener diodes do not have sufficient transient absorption capability, a higher-power transzorb must be used. The most package-efficient solution involves using a single transzorb and back-to-back diodes between the device inputs, as shown in Figure 9-6. The most space-efficient solutions are dual, series-connected diodes in a single SOT-523 or SOD-523 package. In either of the examples shown in Figure 9-5 and Figure 9-6, the total board area required by the INAx180-Q1 with all protective components is less than that of an SO-8 package, and only slightly greater than that of an MSOP-8 package.
For a reference design example, see Current Shunt Monitor With Transient Robustness Reference Design.