ADL - Linearization for ADCs 1.1
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Digital post‑linearization increases the effective resolution of analog‑to‑digital conversions. The linearization technology developed by SP Devices suppresses low order non‑linearities of high‑performance ADCs and non‑linearities caused by pre‑ADC analog components (such as amplifiers, filters and buffers).
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The transfer function of ADCs
The SP Devices linearization technology increases the useful dynamic range of A/D solutions. An ADC can be viewed as a transfer function from the analog to digital domain. An ideal ADC has a completely linear transfer function.
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All ADCs are non-linear
However, the transfer functions of all real ADCs suffer from non‑linearities. These non‑linearities limit the dynamic range of the ADC and often limit the usefulness of many applications.
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The ADL technology
The ADL is digital block for the post‑processing of the output from ADCs that enhances the linearity of the ADC. The ADL improves the dynamic range in most applications by a factor of at least two.
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ADL compensates
- Static nonlinearities
- Frequency dependent nonlinearities
ADL features
- Black box model which captures frequency dependent non-linear behavior
- Self learning and does not need any calibration signal
- Suppresses low-order non-linear distortion
- SFDR for higher Nyquist zone improved to the same levels as lower Nyquist zone
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ADL improvement results
Below is the result of applying ADL on high speed 16-bit ADCs presented.
Analog Devices AD9461
- ADL extends the linear bandwidth beyond 5th Nyquist zone
- ~20 dB DR improvement for 287 MHz & 289 MHz @ fs = 130 MSps

National Semiconductor ADC16V130
- ADL extends the linear bandwidth beyond 5th Nyquist zone
- ~15 dB DR improvement for 287 MHz & 289 MHz @ fs = 130 MSp

Texas Instruments ADS5483
- ADL extends the linear bandwidth beyond 5th Nyquist zone
- ~30 dB DR improvement for 287 MHz & 289 MHz @ fs = 130 MSps

Linear Technology LTC2209
- ADL extends the linear bandwidth beyond 5th Nyquist zone
- ~25 dB DR improvement for 287 MHz & 289 MHz @ fs = 130 MSps

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