analog to digital converter box for motorola

Resistance means coupled between the first and second reference voltages, for developing on each of a rank ordered plurality of step nodes a predetermined step voltage between the first and second reference voltages and Voltage divider means for providing a step voltage selected between first and second reference voltages in response to the digital input code, comprising: In a converter for providing an analog output signal corresponding to a digital input code, comprising: Coupled directly to the C DAC is an operational amplifier receive filter circuit which utilizes the C DAC as an input capacitor thereby eliminating the need for a buffer amplifier and allowing the DAC to be used for both analog to digital and digital to analog conversion.ġ. The DAC is asynchronous and has programmable A-and Mu-255 law PCM conversion capability.

The DAC provided utilizes an R ladder DAC coupled directly to a C DAC and has a switching structure that is simpler than comparable prior art circuits.

One embodiment of the invention is to utilize a companding DAC having a capacitor array which may be used as the output capacitance of the operational amplifier circuit. The multi-function circuit provides a large savings in circuit area and permits versatility of circuit applications. A single operational amplifier utilizes switched capacitors for sampling and holding an input signal, for establishing a low frequency pole, for applying the sample to an output capacitance to charge the capacitance and for comparing the input signal with a reference. An operational amplifier capable of selectively performing a variety of circuit functions is provided.

Analog to digital converter box for motorola