Applications involving large input transients with excessive dV/dt above 2 kV per microsecond present at the device input pins can cause damage to the internal ESD structures on version A devices. This potential damage is a result of the internal latching of the ESD structure to ground when this transient occurs at the input. With significant current available in most current-sensing applications, the large current flowing through the input transient-triggered, ground-shorted ESD structure quickly results in damage to the silicon. External filtering can be used to attenuate the transient signal prior to reaching the inputs to avoid the latching condition. Take care to ensure that external series input resistance does not significantly affect gain error accuracy. For accuracy purposes, keep the resistance under 10 Ω if possible. Ferrite beads are recommended for this filter because of their inherently low dc ohmic value. Ferrite beads with less than 10 Ω of resistance at dc and over 600 Ω of resistance at 100 MHz to 200 MHz are recommended. The recommended capacitor values for this filter are between 0.01 µF and 0.1 µF to ensure adequate attenuation in the high-frequency region. This protection scheme is shown in Figure 7-7. Again, see TIDA-00302 Transient Robustness for Current Shunt Monitor Design Guide, TIDU473 for more information on transient robustness and current-shunt monitor input protection.

Figure 7-7 Transient Protection

To minimize the cost of adding these external components to protect the device in applications where large transient signals may be present, version B and C devices are now available with new ESD structures that are not susceptible to this latching condition. Version B and C devices are incapable of sustaining these damage-causing latched conditions so these devices do not have the same sensitivity to the transients that the version A devices have, thus making the version B and C devices a better fit for these applications.