8. DCO ΣΔ : Design Considerations Composite ΣΔ Noise ↑, N ↑ , M ↓ , TB size ↑, f CLK ↓ Critical parameters: M, CLK, N, δ C -> Δ f Due to resolution of digital input (M) Due to size of capacitor Δ f Reference [3] - Bogdan Staszewski, Chih-Ming Hung
9. DCO ΣΔ : Design Considerations Effect of SD order (N) M = 10, Δ f = 30kHz, f CLK = 450MHz N = 1 N = 2 N ↑ , L SD,M Х , L SD, Δ f lower between 1-10M & higher @ 100MHz Composite response (solid black line) DOES NOT include natural DCO phase noise!
10. DCO ΣΔ : Design Considerations Effect of Fractional Word Length (M) N = 2, Δ f = 30kHz, f CLK = 450MHz M = 2 M = 10 Composite response (solid black line) DOES NOT include natural DCO phase noise! M ↑ , L SD,M ↑ , L SD, Δ f X, Current consumption ↑
11. DCO ΣΔ : Design Considerations Effect of Capacitor Size ( Δ f) M = 10, N = 2, f CLK = 450MHz Δ f = 10kHz Δ f = 30kHz Δ f ↑ , L SD,M ↑ , L SD, Δ f ↑ Composite response (solid black line) DOES NOT include natural DCO phase noise!
12. DCO ΣΔ : Design Considerations Effect of ΣΔ Clock ( f CLK ) M = 10, N = 2, Δ f = 30kHz f CLK = 225MHz f CLK = 450MHz f CLK ↑ , L SD,M X , L SD, Δ f ↑ Composite response (solid black line) DOES NOT include natural DCO phase noise!
57. DCO Gain Calibration & Compensation Without calibration and compensation, the phase error of the transmitter will fail 3GPP GSM specification. GSM 3GPP limit (5 degrees) Measured Simulated Target specification (3 degrees)
60. TDC Calibration & Compensation Error needs to be within ±2% to meet 3 RMS phase-error spec.
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62. Calibration of DCO Current Variation of DCO Phase Noise Operating beyond optimum bias setting effects the DCO reliability. 400kHz Offset
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64. Calibration of DCO Current Validation of Proposed Solution Optimum DCO current using PHE based estimation PHE based estimation of DCO noise correlates with the measured DCO integrated noise.
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66. DCO Frequency Calibration & Compensation The allocated time for ADPLL lock may not be adequate given DCO center frequency variation.
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69. Noisy/Defective vs. Normal DCO PTE is determined based on PHE based estimation of DCO noise. References [5] - Oren Eliezer, Imran Bashir
70. Block Diagram for Cap. Test DCO phase capacitor toggling time domain PHE waveform H(S) References [5] - Oren Eliezer, Imran Bashir