BUILT-IN SELF TEST CIRCUIT FOR MEASURING PHASE NOISE OF A PHASE LOCKED LOOP
First Claim
1. An apparatus for measuring phase noise of a device under test (DUT), the apparatus comprising:
- a first phase detector configured to receive a first signal from the DUT and first clock signal from a timing generator, wherein the first phase detector is further configured to measure a phase error between the first signal and the first clock signal and output a first phase error signal;
a first charge pump configured to receive the first phase error signal and generate a first current;
a first capacitor configured to receive the first current and provide a first voltage;
a first voltage controlled delay line (VCDL) configured to receive a second clock signal and the first voltage, and output a first delay signal indicative of a delay proportional to the first voltage; and
a first 1-bit time-to-digital converter (TDC) configured to receive a third clock signal and the first delay signal and output a first logical value if the first delay signal leads the third clock signal and output a second logical value if the first delay signal lags the third clock signal.
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Abstract
An apparatus and method for providing a phase noise built-in self test (BIST) circuit are disclosed herein. In some embodiments, a method and apparatus for forming a multi-stage noise shaping (MASH) type high-order delta sigma (ΔΣ) time-to-digital converter (TDC) are disclosed. In some embodiments, an apparatus includes a plurality of first-order ΔΣ TDCs formed in an integrated circuit (IC) chip, wherein each of the first-order ΔΣ TDCs are connected to one another in a MASH type configuration to provide the MASH type high-order ΔΣ TDC, wherein the MASH type high-order ΔΣ TDC is configured to measure the phase noise of a device under text (DUT).
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Citations
20 Claims
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1. An apparatus for measuring phase noise of a device under test (DUT), the apparatus comprising:
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a first phase detector configured to receive a first signal from the DUT and first clock signal from a timing generator, wherein the first phase detector is further configured to measure a phase error between the first signal and the first clock signal and output a first phase error signal; a first charge pump configured to receive the first phase error signal and generate a first current; a first capacitor configured to receive the first current and provide a first voltage; a first voltage controlled delay line (VCDL) configured to receive a second clock signal and the first voltage, and output a first delay signal indicative of a delay proportional to the first voltage; and a first 1-bit time-to-digital converter (TDC) configured to receive a third clock signal and the first delay signal and output a first logical value if the first delay signal leads the third clock signal and output a second logical value if the first delay signal lags the third clock signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A multi-stage noise shaping (MASH) type high-order delta sigma (Δ
- Σ
) time-to-digital converter (TDC), comprising;a first first-order Δ
Σ
TDC configured to receive a first signal from a device under test (DUT) and a first clock signal, wherein the first first-order Δ
Σ
TDC is configured to measure a phase difference between the first signal and the first clock signal and convert the phase difference to a first digital value; anda second first-order Δ
Σ
TDC configured to receive a first residue signal from the first first-order Δ
Σ
TDC and the first clock signal, wherein the second first-order Δ
Σ
TDC is configured to measure a phase difference between the first residue signal and the first clock signal and convert the phase difference to a second digital value. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A method of converting noise into a digital signal, the method comprising:
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providing a first reference signal to a device under test (DUT) and a first node of a first delta sigma (Δ
Σ
) time-to-digital converter (TDC);providing a first feedback signal from the DUT to a second node of the first Δ
Σ
TDC;providing a second reference signal to a third node of the first Δ
Σ
TDC;providing a third and a fourth reference signal to a fourth and a fifth node, respectively, of the first Δ
Σ
TDC;providing a first output of the first Δ
Σ
TDC as a second feedback signal to a sixth node of the first Δ
Σ
TDC, wherein the second feedback signal selects either the third or fourth reference signal to provide to a seventh node of the first Δ
Σ
TDC; andsaving a digital output of the first Δ
Σ
TDC in a memory. - View Dependent Claims (19, 20)
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Specification