Abstract: A delay time calculation method and a delay time calculation system for a semiconductor integrated circuit that enables timing testing to be efficiently performed. The propagation delay time for a signal path taking into consideration variations in the chip is calculated based on a corrected variation coefficient. The corrected value of the variation coefficient is calculated based on a function that approximates the propagation delay time caused by variations in the chip as a propagation delay time affected by the actual variations in the chip in accordance with the number of cell stages in the signal path. Accordingly, the propagation delay time is calculated to have an appropriate occurrence probability corresponding to a 3&sgr; range in the probability density distribution.

Abstract: An interleaved auto-zero analog-to-digital converter includes chopper comparators for comparing an analog input signal to predetermined voltage values. An additional chopper comparator is included for performing the comparison function of a chopper comparator undergoing an auto zero operation.

Abstract: A data access controller for a disc device is disclosed for accessing data on a disc. A control unit, controlling the disc device, outputs a mode switching signal. A mark detector detects the sector mark and the address mark in read data from a target sector, and outputs a first and second detection signals indicative of the detections of the sector mark and address mark, respectively. In response to the mode switching signal, the mark detector enters a first search mode to detect all data bits of the target sector. A physical address read circuit reads physical address data in the read data in response to the second detection signal, and outputs a synchronizing signal. The format counter receives a basic clock signal to count the number of pulses of the clock signal, and resets its count value to a prescribed value in accordance with the first detection signal and the synchronizing signal to synchronize its count value with the position of the drive head on the target sector.