8.2 V common-cathode pair for signal-line clamping
The UMZ8.2TFHT106 is a dual common-cathode zener array from ROHM's automotive-grade series, qualified to AEC-Q101. It delivers a nominal 8.2 V regulation point in a single SC-70 package, replacing two discrete zeners and cutting placement cost on terminal-protection circuits. Rated at 200 mW maximum power dissipation, the part is sized for low-current clamping on data lines, I/O ports, or supply-rail transients where the energy per event stays within the SC-70 thermal envelope.
Leakage and impedance — the standby and clamping trade-off
Reverse leakage is specified at 500 nA maximum when biased at 5 V — low enough to avoid draining a coin cell or supercap in a parked ECU module. Maximum zener impedance (Zzt) is 30 Ohms, which sets the dynamic resistance during reverse breakdown. For a 5 mA clamping current the voltage drop across the internal resistance adds roughly 150 mV to the nominal 8.2 V.