ZHCSK76 September 2019 LM74202-Q1
PRODUCTION DATA.
To protect the device and the load from input transients exceeding the absolute maximum ratings of the device, a TVS diode is required at input of the device. To meet the requirements of protection for ISO 16750 pulse 5b and ISO 7637 pulse 1 as per Table 5, SMBJ28CA is selected for protection from transients.
| Parameter | ISO 16750 Pulse 5b | ISO 7637 Pulse 1 and Reverse Battery | |
|---|---|---|---|
| Maximum Transient Voltage of Pulse (VT) | 35 V | -150V | A bidirectional TVS is required to protect from positive and negative transients |
| Pulse Current through TVS (IPulse) | (VT - VC)/(Ri) | (VT - VC)/(Ri) | Ri = Source impedance.
For ISO 16750 Pulse 5b; Ri = 0.5 Ω For ISO 7637 Pulse 1;Ri = 10 Ω |
| Clamping voltage of TVS (VC) at Pulse current IPulse | < 55 V | > –(55 - VOUT-Max) V | To keep input voltage below absolute maximum rating of the device. See Equation 13 for VC |
| Breakdown voltage of TVS (VBR) | > 32V | > 14V | To operate with maximum operating input voltage and to protect from maximum reverse battery voltage |
where