The SMM105 actively controls the output voltage level of a DC/DC converter that uses a Trim or VADJ/FB pin to adjust the output. An Active DC Output Control (ADOCTM) feature is used during normal operation to maintain extremely accurate settings of supply voltages and, during system test, to control margining of the supplies using I2C commands. Total accuracy with a 0.1% external reference is 0.2%, and 0.5% using the internal reference. The device can margin supplies with either positive or negative trim pin control within a range of 0.3V to VDD. The SMM105 supply can be from 12V, 8V, 5V or 3.3V to as low as 2.7V to accommodate any intermediate bus supply. The voltage settings (margin high/low and nominal) are programmed into nonvolatile memory through the industry standard I2C 2-wire data bus. The I2C bus is also used to enable margin high, margin low, ADOC or normal operation. When margining, the SMM105 will check the voltage output of the converter and make adjustments to the trim pin via a feedback loop to bring the voltage to the margin setting. A margining status register is set to indicate that the system is ready for test. The SMM105 ADOC will continue to monitor and adjust the channel output at the specified level.