Patent ID: 8472552

Claim:
A wireless device transmitter for transmitting a radio frequency (RF) output signal, said transmitter comprising: an input stage for receiving a modulated digital signal; an oversampling stage for increasing a frequency of said modulated digital signal to form an oversampled signal of i bits in size, where i is an integer value greater than 1; and a digital to analog converter (DAC) circuit for receiving said i bits of the oversampled signal, said DAC circuit including: a delta sigma (ΔΣ) converter for generating a first analog signal, which is a first current, corresponding to j least significant bits of the oversampled signal; a weighted transistor digital to analog converter for receiving i-j most significant bits of the oversampled signal and for generating i-j corresponding analog signals, which are i-j corresponding currents, where j is an integer value greater than 1 and less than i; a current summing element for generating a final current corresponding to the aggregate sum of the first current and the i-j corresponding current; and a current mirror circuit having a first order filtering circuit for receiving the final current to provide a filtered final current signal.