DIO2399A/B

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DIO2399A/B• Rev. 1.7

Figure 12. DIO2399X transient protection using a single transzorb and input clamps

Improving transient robustness

Applications involving large input transients with excessive dV/dt above 2 kV per microsecond present at the

device input pins may 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. Care must be

taken to ensure that external series input resistance does not significantly impact gain error accuracy. For

accuracy purposes, these resistances should be kept 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 13. (Note: Capacitors used in high voltage applications should be greater

than or equal to 30 V)

Figure 13. 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 devices are now available with new ESD structures that are not

susceptible to this latching condition. Version B devices are incapable of sustaining these damage causing

latched conditions so they do not have the same sensitivity to the transients that the version A devices have,

thus making the version B devices a better fit for these applications.