Abstract: An integrated circuit I/O buffer has an output driver. The output driver includes first, second and third voltage supply terminals and a pad terminal. A pad pull-up transistor is coupled in series between the first voltage supply terminal and the pad terminal and has a pull-up control terminal. A pad pull-down transistor is coupled in series between the second voltage supply terminal and the pad terminal and has a pull-down control terminal. A voltage protection transistor is coupled between the pad terminal and the pad pull-down transistor. The voltage protection transistor has a control terminal and a capacitance between the control terminal and the pad terminal. A resistor is coupled in series between the control terminal of the voltage protection transistor and the third voltage supply terminal and forms a resistor-capacitor (RC) circuit with the capacitance.

Abstract: A means and method for testing high speed phase locked loops (13) in an integrated circuit (12) at a test frequency lower than the operation speed of the phase locked loop (13). A test circuit portion (10) repeatedly tests for a zero level (42) of a recover clock signal (34) from the phase locked loop (13) and a latching flip flop (26) is set to provide a lock indication output (30) as long as repeated samples, taken at a test time (38) continue to indicate a zero level (42) of the recover clock signal (34). The test time (38) is the leading edge (40) of a reference clock signal (36) provided from an external source at a reference clock input (28) to the integrated circuit (12).

Abstract: A high speed capture latch includes differential data inputs, a latch clock input, a boost clock input, a current steering circuit, a switched current source, a latch element and first and second boost current sources. The current steering circuit has first and second differential control terminals which are coupled to the differential data inputs and control current through first and second current paths, respectively. The switched current source is coupled between the current steering circuit and a first voltage supply terminal and has a control terminal coupled to the latch clock input. The latch element is coupled between a second voltage supply terminal and the current steering circuit and provides a latch output. The first boost current source is coupled to the first current path between the latch element and the current steering circuit and has a control terminal coupled to the boost clock input.

Abstract: A voltage-controlled oscillator includes at least one voltage-controlled delay element and a reference voltage generator. The voltage-controlled delay element has first and second voltage supply inputs, a control voltage input, a signal input and a signal output. The reference voltage generator has a voltage input coupled to the control voltage input and a voltage output coupled to the first voltage supply input.

Abstract: A self-timed phase detector for detecting the phase of an input signal, such as a high speed serial data stream. The self-timed phase detector includes a precharged latch, a phase detector circuit and a data valid gate. The precharged latch has a latch input, a sample clock input and first and second complementary latch outputs. The first and second complementary latch outputs have an active state and a precharged state. The phase detector circuit is coupled to the first latch output and generates a phase signal on a phase output as a function of the phase of the input signal. The data valid gate is coupled to the phase output for passing the phase signal when the latch outputs are in the active state and for blocking the phase signal when the latch outputs are in the precharged state.

Abstract: A bit serial decoder is disclosed decoding an encoded non-return to zero (NRZ) signal without the use of external clock. Transitions within the encoded NRZ signal cause a differential voltage signal to be output. This differential voltage increases at a constant rate between two transitions. At the second transition the magnitude of the differential voltage is compared to a preset value to determine a number of consecutive like bits. These consecutive bits can then be transmitted in one step to a storage means.

Abstract: A self-timed memory control system including a dummy row and column of memory cells along adjacent edges of a core memory array. Control logic receives an external clock signal and initiates address decoding, and also asserts a sense enable signal for activating the sense amplifiers. A dummy driver receives the enable signal and asserts a select signal on a dummy select line, which causes a memory access to occur in the dummy portion simultaneously with each access of the core memory array. A fixed memory cell in the dummy path always asserts a logic zero to a dummy sense amplifier, which senses the logic zero and respondingly asserts a timing signal. The dummy sense amplifier is biased with a voltage offset to favor a logic one, so that the timing signal is preferably delayed until after the output data of the core memory array has stabilized.