Abstract: A semiconductor device for suppressing transient voltages is adapted for use on high frequency data lines. The semiconductor device combines an avalanche type diode which has high capacitance in series with a rectifying diode which has a capacitance three magnitudes lower. The resultant semiconductor device is fabricated using a single, monolithic silicon die instead of stacking two separate dies as has been done in prior art transient voltage suppressors to achieve the same characteristics. The semiconductor die is adaptable for packaging in surface mountable DIP packages and other common circuit board mountable packages.