Introducing the Radiation-Hardened Voltage Regulators Rhfl4913 and the Rhfl6000

Abstract

With the progressive scaling of the modern CMOS processes arising during the recent years, for the devices operating in space the susceptivity to the over-voltage events has increased. They have become more stringent the requirements in terms of accuracy of the supply voltage worth their reliability. For the case of CMOS memories operating at 1.5V it is essential to guarantee a variation of the nominal VOUT to within 5% including those arising on the supply voltage during the transients. Finally, for a voltage regulator operating in space one of the most salient effects are the voltage transients induced on the output by the single events (SET) that may exceed the aforementioned 5% threshold. This can be cause of damage into the circuitry fed downstream. Among the devices in ST portfolio designed to cope with the mentioned effects there are two voltage regulators, the RHFL4913 and the RHFL6000. The first one was initially developed for the harsh environment of the Large Hadron Collider. It was tested by the CERN and it was proven that it is able to operate without problems at up to 100Mrad TID at High Dose Rate without problems 1. Subsequent tests performed at low dose rates (expected in space environment), showed that this device is also ELDRS free up to 1Mrad 2. Further tests performed by NASA highlighted also a certain susceptivity to the SET (3) but this issue can be circumvented by the adoption of a properly sized up RC low pass filter put between the regulator output and the load as shown in fig.1 (4). With the above provision, this regulator is suitable for operating in space. Currently, the RHFL4913 is QMLV qualified.