Abstract: Methods and apparatus are provided for improving the jitter tolerance in an SFP limit amplified signal. Jitter tolerance is improved in a communications receiver by applying a received signal to an SFP limiting amplifier; and applying an output of the SFP limiting amplifier to a low pass filter to improve the jitter tolerance. The low pass filter optionally applies a programmable amount of attenuation to high frequency components of the output. The low pass filter slew rate controls (i.e., rotates) a data eye representation of the received signal to increase the data eye representation along a time axis. The noise margin of the received signal can optionally be improved by applying an output of the low pass filter to an all pass filter. A slew rate controller can evaluate the data eye statistics to determine a setting for the low pass filter.

Abstract: A method comprises providing a free buffer pool in a memory including a non-negative number of free buffers that are not allocated to a queue for buffering data. A request is received to add one of the free buffers to the queue. One of the free buffers is allocated to the queue in response to the request, if the queue has fewer than a first predetermined number of buffers associated with a session type of the queue. One of the free buffers is allocated to the queue, if a number of buffers in the queue is at least as large as the first predetermined number and less than a second predetermined number associated with the session type, and the number of free buffers is greater than zero.

Abstract: A duty-cycle correction (DCC) circuit adapted to adjust the duty cycle of a differential clock signal to conform it to the requirements of a half-rate clocking system. In a representative embodiment, the DCC circuit has a buffer circuit adapted to generate a differential output clock signal by adding offset voltage to a differential input clock signal. A feedback loop coupled to the buffer circuit processes the output clock signal to evaluate deviation of its duty-cycle value from 50% and, based on the evaluation, configures the buffer circuit to adjust the offset voltage such that the duty-cycle deviation is reduced. The feedback loop and the buffer circuit are controlled by a duty-cycle calibration engine, e.g., a digital logic circuit adapted to determine an appropriate value for the offset voltage, which causes the duty-cycle value in the output clock signal to be substantially 50% regardless of the duty-cycle value in the input clock signal.

Abstract: A motor controller for an electric motor having a plurality of motor terminals is connected to a power supply and comprises a commutation control, a current sensor, a peak target circuit, a pulse width control and a reverse current control. The commutation control is connected to the motor terminals for causing current pulses to flow through selected terminals during each commutation state. The current sensor provides a sense signal representative of the current pulses, and the peak current target circuit provides a target signal. The pulse width control controls pulse width of the current pulses as a function of the sense signal and the target signal. The reverse current control prevents reverse current from flowing into the power supply during change of commutation state.

Abstract: A method for testing integrated circuits, including measuring a current signature delta value of a device under test and comparing the current signature delta value to a threshold current signature delta value to determine whether the current signature delta value is greater than the threshold current signature delta value. If the current signature delta value exceeds the threshold current signature delta value, the integrated circuit is rejected. Integrated circuits are also rejected if the post-stress current signature value exceeds a maximum current signature value, even though the current signature delta value is less than the threshold current signature delta value. In addition, an apparatus for testing integrated circuits is disclosed.