Abstract: The present invention provides methods and apparatus for trimming semiconductor devices and circuits, such as pin electronics circuits used in automated test equipment (ATE) systems and the like, without requiring a laser trimming operation. In a preferred embodiment, the present invention addresses the need to precisely adjust a reference current and/or voltage by replacing a conventional current/voltage reference source with a digital-to-analog (D/A) converter. A select switch or mechanism is preferably coupled to the input of the D/A converter and operatively presents a digital input word to the D/A converter by selectively reading the digital word from at least one of a data register and a fuse register. The data register is preferably used during testing of the overall current or voltage reference by iteratively trying various digital input codes while concurrently measuring the analog output signal from the D/A converter until the output signal sufficiently matches a predetermined output value.

Abstract: The present invention provides methods and apparatus for trimming semiconductor devices and circuits, such as pin electronics circuits used in automated test equipment (ATE) systems and the like, without requiring a laser trimming operation. In a preferred embodiment, the present invention addresses the need to precisely adjust a reference current and/or voltage by replacing a conventional current/voltage reference source with a digital-to-analog (D/A) converter. A select switch or mechanism is preferably coupled to the input of the D/A converter and operatively presents a digital input word to the D/A converter by selectively reading the digital word from at least one of a data register and a fuse register. The data register is preferably used during testing of the overall current or voltage reference by iteratively trying various digital input codes while concurrently measuring the analog output signal from the D/A converter until the output signal sufficiently matches a predetermined output value.

Abstract: A current limiter circuit for limiting current in an electrical circuit element such as the magneto-resistive portion of a read head forming a portion of a hard disk drive and including: a first circuit connected to one end of the circuit element for applying a bias current of a desired value to the circuit element in response to the value to an input signal; a second circuit connected to the other end of the circuit element for setting the amplitude of the voltage signal generated across the circuit element in response to the bias current; and a third electrical circuit connected to both the first and second circuits for limiting the value of bias current to a predetermined level for an abnormal event such as a current surge, a short circuit, or any other type of undesired current operating condition.