Abstract: A novel circuit topology which provides for the digital automatic gain control of a VCO is disclosed. The topology of the VCO is based on the negative transconductance oscillator due to its intrinsically simple biasing scheme. A system parameter sensitive to the performance level of the VCO is firstly measured. A digital control signal is then generated in response to the measured system parameter. The biasing current provided by the tail circuit of the VCO is adjusted based on the value of the digital control signal. In this way, the biasing current of the VCO may be adjusted to an optimal value for all frequencies of operation. The automatic control aspects of the present invention is useful in monolithic implementations since it automatically compensates for variations in load resistance, process parameters and component tolerances without requiring expensive manual adjustments at the board level.

Abstract: The gain and current consumption of a power amplifier are adjusted while maintaining amplified output signal linearity. Where linearity and low power consumption are maintained for the amplifier by controllable shunting of an input signal amplitude and by providing a predetermined bias signal to the amplifier circuit in a precalibrated manner. A mapping circuit is disposed for receiving a control signal and for providing the predetermined bias signal to the amplifier circuit in the precalibrated manner. The mapping circuit is either internally provided within the same circuit as the power amplifier, or externally.

Abstract: A circuit for controlling a high frequency power amplifier for amplifying a signal for wireless transmission is disclosed. The circuit provides a control signal to the power amplifier at an output port thereof. The control signal has properties of rise time and fall time, where a delayed transition in this signal is based on charging and discharging of the capacitor using two current mirror circuits in order to provide the delayed transition. An advantage lies in that the time of this delayed transition is dependent primarily upon the current mirrors and substantially other than dependent upon the RC time constant of the circuit.

Abstract: A method of producing a bipolar transistor includes the step of providing a sacrificial mesa over a layer of SiGe in order to prevent a polysilicon covering layer from forming over a predetermined region of the SiGe layer forming the transistor base. After an etching process removes the sacrificial mesa and the SiGe layer is exposed, an oppositely doped material is applied over top of the SiGe layer to form an emitter. This makes it possible to realize a thin layer of silicon germanium to serve as the transistor base. This method prevents the base layer SiGe from being affected, as it otherwise would be using a conventional double-poly process.

Abstract: A method of producing a bipolar transistor includes the step of providing a sacrificial mesa over a layer of SiGe in order to prevent a polysilicon covering layer from forming over a predetermined region of the SiGe layer forming the transistor base. After an etching process removes the sacrificial mesa and the SiGe layer is exposed, an oppositely doped material is applied over top of the SiGe layer to form an emitter. This makes it possible to realize a thin layer of silicon germanium to serve as the transistor base. This method prevents the base layer SiGe from being affected, as it otherwise would be using a conventional double-poly process.

Abstract: A two stage amplifier for a portable or cellular phone is disclosed which is manufactured using a fast BiCMOS process suach as SiGe. A shunt circuit controlled by a switch is provided between a base of one of the amplifying transistors and a DC terminal to prevent it from operating in a Class B mode of operation when it is intended for the amplifier to be switched off.

Abstract: Recent trends have seen the desire for lower and lower supply voltages in radio frequency (RF) components as this leads to lower power consumption and, therefore, longer battery life. As well, lower voltages and less current means that mobile products can be made to require fewer battery cells leading to lighter, more compact devices. The present invention discloses a novel topology for providing a low-voltage voltage-controlled oscillator (VCO). The novel topology is based on the negative transconductance oscillator. However, the novel topology of the invention eliminates transistor ‘stacking’ in the oscillator circuit, thereby allowing the oscillator circuit to be operated at a supply voltage only slightly higher than the turn-on voltage for a single transistor.