Integrated testing circuitry for high-frequency receiver integrated circuits

#This invention relates to an integrated circuit, comprising a receiver and an oscillator circuit.

#The invention also relates to an apparatus for testing the proper functioning of an integrated circuit, the integrated circuit comprising a receiver and an oscillator circuit.

#The invention further relates to a method of producing a receiver.

#FIG. 1 schematically shows an example of an embodiment of an integrated circuit comprising a receiver and an oscillator circuit for generating a high frequency test signal.

#FIG. 2 schematically shows an example of an embodiment of a receiver.

#FIG. 3 schematically shows an example of an embodiment of a frequency converter.

#Further details, aspects and embodiments of the invention will be described, by way of example only, with reference to the drawings. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. Identical, similar or analogous components appearing in different figures are labelled using the same reference numerals and are not necessarily described more than once.

#FIG. 1 schematically shows an example of an embodiment of an integrated circuit 10 on a wafer. The integrated circuit 10 comprises a receiver 12 and an oscillator circuit 22, 26, 32, 38. The receiver 12 has a first input port (HF port) 14 for receiving a first oscillatory input signal, a second input port (LO port) 16 for receiving a second oscillatory input signal, and an output port 18 for delivering an oscillatory output signal (IF signal) which is a function of both the first input signal and the second input signal. The oscillator circuit 22, 26, 32, 38 has a first output port 36 for delivering a first oscillatory signal (HF signal), and a second output port 42 for delivering a second oscillatory signal (LO signal). Herein it is understood that the oscillator circuit 22, 26, 32, 38 is capable of generating both the HF signal and the LO signal. The first output port 36 of the oscillator circuit is coupled to the HF port 14, while the second output port 42 of the oscillator circuit is coupled to the LO port 16. Thus the HF signal can be generated on the same die or wafer that also carries the receiver 12, and it may be used for testing the receiver 12 without feeding the HF signal to the receiver 12 from an external apparatus (not shown). The frequency of the IF signal may be lower than the frequency of the HF signal. For example, the HF signal may have a frequency fHF above 1 GHz while the IF signal has a frequency fIF below 100 MHz. In the example shown, the oscillator circuit further comprises a first detector 44 for measuring the power or amplitude of the HF signal transmitted to the HF port 14. In this example, the oscillator circuit also comprises a second detector 46 for measuring the power or amplitude of that part of the HF signal that is reflected from the HF port 14. The dotted lines indicate that the detector 44 and the detector 46 are coupled to the conductor joining the oscillator circuit's port 36 to the HF port 14, for example by means of a so called rat race coupler, or by any other suitable arrangement of directional couplers. In the example shown, the oscillator circuit further comprises a third detector 48 for measuring the power or amplitude of the LO signal transmitted to the LO port 16. In this example, the oscillator circuit further comprises a fourth detector 50 for measuring the power or amplitude of that part of the LO signal that is reflected from the LO port 16. As indicated by the dotted lines, the detectors 48 and 50 are both coupled to a conductor joining the output port 42 to the LO port 16, for example by means of a rat race coupler, analogously to the arrangement of detectors 44 and 46 mentioned above. In the example shown, the oscillator circuit comprises an oscillator 22 having an output port 24 for delivering an oscillatory oscillator signal. The oscillators output port 24 is coupled to the HF port 14 and to the LO port 16. The oscillator circuit further comprises an amplifier 32 having an input port 34 for receiving an input signal, and an output port 36 for delivering an output signal that is essentially proportional to the input signal. The output port 24 of the oscillator 22 is coupled to the input port 34 of the amplifier 32. The output port 36 of the amplifier 32 is coupled to the HF port 14. The amplifier 32 may be a variable gain amplifier, in which case its gain or its output power may be varied, e.g. by varying an external DC voltage applied to a control port (not shown) of the amplifier 32. The oscillator circuit further comprises a second amplifier 38 having an input port 40 for receiving an input signal, and an output port 42 for delivering an output signal that is essentially proportional to the input signal. The output port 24 of the oscillator 22 is coupled to the input port 40 of the second amplifier 38. The output port 42 of the second amplifier 38 is coupled to the LO port 16. The second amplifier 38 may be a variable gain amplifier, as described above with reference to the first amplifier 32. In the example shown, the oscillator circuit further comprises a frequency converter 26 having an input port 28 for receiving an input signal, and an output port 30 for delivering an output signal having a frequency which differs from the frequency of the input signal, for example by an offset of between 10 kHz and 10 MHz. The output port 24 of the oscillator 22 is coupled to the input port 28 of the frequency converter 26. The output port 30 of the frequency converter 26 is coupled to the LO port 16 (in the example shown, additional elements are coupled between the output port 30 and the LO port 16). The circuit 10 thus allows feeding to the receivers HF port 14 and to its LO port 16 respectively a high frequency signal at frequency fHF and a high frequency signal at frequency fLO in order to simulate the input signals which during normal operation of the receiver 12 would be received from an antenna and generated by a local oscillator, respectively. The oscillator 22 may in particular be a voltage controlled oscillator (VCO). In this case the generated frequency fHF is a function of a control voltage applied to the VCO.

#During operation of the device 10, the oscillator 22 generates a high frequency signal of frequency fHF, e.g. 76.5 GHz. This signal is fed to the HF input port 14 of the receiver 12 via the amplifier 32 and a temporary conductor between the ports (or pads) 36 and 14. Another part of the output signal generated by the oscillator 22 at frequency fHF is fed to the frequency converter 26 which converts the signal to a frequency fLO which, according to an exemplary embodiment, is 5 MHz lower than the frequency fHF of the initial signal. The signal at frequency fLO, which is intended to simulate a local oscillator signal, is fed to the receivers LO port 16 via the second amplifier 38 and a temporary conductor joining the amplifiers output port 42 to the receivers LO port 16.