SLVSFD0 September 2019 LM74202-Q1
PRODUCTION DATA.
In case of short circuit and over load current limit, when the device interrupts current flow, input inductance generates a positive voltage spike on the input and output inductance generates a negative voltage spike on the output. The peak amplitude of voltage spikes (transients) is dependent on value of inductance in series to the input or output of the device. Such transients can exceed the Absolute Maximum Ratings of the device if steps are not taken to address the issue.
Typical methods for addressing transients include:
The approximate value of input capacitance can be estimated with Equation 14.
where
Automotive applications could require additional Transient Voltage Suppressor (TVS) to prevent transients from exceeding the Absolute Maximum Ratings of the device. These transients include ISO 7637 Pulse 1, Output short to battery, Output short to GND and reverse battery at input.
The circuit implementation with optional protection components (TVS Diode at Input and schottky diode at output) is shown in Figure 46. For protection from automotive transients similar to ISO 7637 Pulse 1, Output short to battery , output short to GND and reverse battery, use CIN ≥ 1 µF and COUT ≥ 3.3 µF. For selection of TVS diode and other components, see Application Information.