Embodiments of the present invention pertain to wireless circuits, and more particularly, to a wireless communication system for testing and configuring circuits on a die.
To test an integrated circuit on a die, it is desirable to have good controllability so as to be able to set various internal nodes to desired logical states, and to have good observability so that appropriate nodes may be observed to determine if the integrated circuit is performing correctly. Usually, controllability and observability are achieved by modifying existing circuit state elements such as latches and flip-flops, and configuring them to form a shift register in a test mode. In some instances, additional state elements are introduced to observe the circuit state, where such state elements are often connected to each other to form a shift register, commonly referred to as a scan chain.
The input and output ports of a scan chain, commonly called test access pins, are connected to the input and output ports of the die under test. The test access pins are often multiplexed with other functional pins of the die. In certain situations, the scan chain may be configured to form a linear feedback shift register (LFSR) so that the response of a circuit under test to multiple stimulus cycles may be stored in the form of a signature. The signature is periodically flushed out to determine the correctness of the circuit behavior. While the use of a scan chain reduces the amount of data to be flushed out, it may also lead to a loss of resolution in diagnosing faulty circuit behavior.
Data captured in the chain scan is observed at the die input and output ports by serially shifting the scan chain (or the LFSR). However, such testing is difficult if the die under test is mounted onto a board or a system where direct access to the test access pins is not practical. Furthermore, based on the number of scan nodes in the circuit under test, multiple scan chains are created to reduce the time to set and observe the scan nodes, which may require multiple test access ports. The need to route the scan chains test access spins to the die periphery may lead to a significant amount of metal interconnect.
An approach suggested to overcome some of the limitation discussed above, limited to circuit testing before wafer sawing, is to make use of a wireless coupling between a circuit under test and the test equipment, where antennas and radio frequency (RF) transceivers are formed on the scribe lines of the wafer and the transceivers are coupled to the integrated circuits. However, such an approach does not lend to testing circuits on an individual die after the wafer has been sawed. Furthermore, direct electrical connection between the RF transceivers and circuits under test may leave exposed wires after wafer sawing, perhaps reducing reliability. In addition, the RF transceivers proposed utilize typical architectures employing modulation and demodulation, whereby signals are up-converted for transmission and down converted to IF frequencies. Such typical transceiver architectures may not be easily implemented in a CMOS (Complementary Metal Oxide Semiconductor) process.
a and 3b illustrate another UWB transceiver architecture.
Data provided to resource control 110 may be transmitted by UWB transceiver 102 to test equipment 118, and data provided by test equipment 118 may be provided to the appropriate functional units 112 and 116 via UWB transceiver 102, MAC 108 and resource control 110. Components on test equipment 118 include UWB transceiver 120, antenna 122, and ATE (Automatic Test Equipment) signal control functional unit 122. ATE signal control may perform encryption and decryption of data that is transmitted or received by UWB transceiver 120.
The components shown in
Traditionally, a UWB transmitter transmits a baseband signal where the frequency content of the transmitted signal includes frequencies from zero to some value representative of the bandwidth of the signal, where the bandwidth if about 500 MHz or greater. In practice, the signal may be a pulse in the time domain. However, more recently, the definition of UWB has been broadened so that UWB transmitters now may employ orthogonal frequency division multiplexing, whereby more than one channel is utilized where each channel occupies non-overlapping portion of the frequency spectrum. In this case, except for the baseband channel, a baseband signal is up-converted to a bandlimited signal centered about a center frequency, where the signal bandwidth is about or greater than 20% of its center frequency.
An example of a UWB transceiver may be illustrated as shown in
The architecture of
The architecture of
Antenna placement may be placed on the die package, and connected to the die via a solder bump. This arrangement is illustrated in
For sorting and testing, it may be advantages to test each of the die on a wafer before the wafer is cut.
Inductive coupling may also be employed. For example, in
An antenna for a die under test may be formed on a circuit board to which the die is attached. For example, a simple plan view of such an embodiment is illustrated in
Various modifications may be made to the disclosed embodiments without departing from the scope of the invention as claimed below. Furthermore, it is to be understood in these letters patent that the meaning of “A is connected to B”, where A or B may be, for example, a node or device terminal, is that A and B are connected to each other so that the voltage potentials of A and B are substantially equal to each other. For example, A and B may be connected by way of an interconnect, transmission line, etc. In integrated circuit technology, the “interconnect” may be exceedingly short, comparable to the device dimension itself. For example, the gates of two transistors may be connected to each other by polysilicon or copper interconnect that is comparable to the gate length of the transistors. As another example, A and B may be connected to each other by a switch, such as a transmission gate, so that their respective voltage potentials are substantially equal to each other when the switch is ON.
It is also to be understood that the meaning of “A is coupled to B” is that either A and B are connected to each other as described above, or that, although A and B may not be connected to each other as described above, there is nevertheless a device or circuit that is connected to both A and B. This device or circuit may include active or passive circuit elements. For example, A may be connected to a circuit element which in turn is connected to B.
It is also to be understood in these letters patent that a “current source” may mean either a current source or a current sink. Similar remarks apply to similar phrases, such as, “to source current”.
It is also to be understood that various circuit blocks, such as current mirrors, amplifiers, etc., may include switches so as to be switched in or out of a larger circuit, and yet such circuit blocks may still be considered connected to the larger circuit because the various switches may be considered as included in the circuit block.
It is also to be understood that a claimed equality or match is interpreted to mean an equality or match within the tolerances of the process technology.