Patent classifications
H03H11/0433
High stability gain structure and filter realization with less than 50 ppm/° c. temperature variation with ultra-low power consumption using switched-capacitor and sub-threshold biasing
An ultra-low power sub-threshold g.sub.m stage is disclosed where transconductance is very stable with process, temperature, and voltage variations. This technique can be implemented in a differential amplifier with constant gain and a second order biquad filter with constant cut off frequency. The amplifier gain can achieve a small temperature coefficient of 48.6 ppm/° C. and exhibits small sigma of 75 mdB with process. The second order biquad can achieve temperature stability of 69 ppm/° C. and a voltage coefficient of only 49 ppm/mV.
HIGH STABILITY GAIN STRUCTURE AND FILTER REALIZATION WITH LESS THAN 50 PPM/°C TEMPERATURE VARIATION WITH ULTRA-LOW POWER CONSUMPTION USING SWITCHED-CAPACITOR AND SUB-THRESHOLD BIASING
An ultra-low power sub-threshold g.sub.m stage is disclosed where transconductance is very stable with process, temperature, and voltage variations. This technique can be implemented in a differential amplifier with constant gain and a second order biquad filter with constant cut off frequency. The amplifier gain can achieve a small temperature coefficient of 48.6 ppm/ C. and exhibits small sigma of 75 mdB with process. The second order biquad can achieve temperature stability of 69 ppm/ C. and a voltage coefficient of only 49 ppm/mV.
CURRENT-MODE FILTER
Aspects of the present disclosure provide techniques and apparatus for current-mode analog signal filtering. An example filter circuit generally includes a current-mode amplifier. The current-mode amplifier includes a first amplifier including an input and an output; a first inverter including an input coupled to the output of the first amplifier and including an output coupled to a first feedback path, the first feedback path being coupled to a first input of the filter circuit; and a second inverter including an input coupled to the output of the first amplifier.
Architecture to reject near end blockers and transmit leakage
A method and apparatus for minimizing transmit signal interference is provided. The method includes the steps of: receiving a signal and amplifying the received signal. The received signal is then mixed with an intermediate frequency signal to obtain a baseband modulated signal. The baseband modulated signal is first filtered in an RC filter. The resulting signal is then divided by a preselected amount and the first divided portion is sent to a main path of a biquad filter, which produces a first stage biquad filtered signal. The second portion of the divided signal is sent to an auxiliary path of the biquad filter, and produces a second filtered signal. The first and second signals are then recombined and sent to the second stage of the biquad filter, where further filtering takes place.