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26-11-2024: CS stage noise performance optimization
===================================================

Lecture: EE4109-5

Location: Pulse Hall 7 (33.A2.200)

Time: 15:45 - 17:30

.. image:: ../../../img/colorCode.svg
    :alt: color coded resistors

Design of CS stage noise behavior
=================================

.. include:: ../../../topics/CSstage/CSstage-intrinsic-noise.rst
.. include:: ../../../topics/CSstage/CSstage-eq-input-noise.rst
.. include:: ../../../topics/CSstage/CSstage-eq-input-noise-SLiCAP.rst
.. include:: ../../../topics/CSstage/CSstage-noise-optimization-resistive.rst
.. include:: ../../../topics/CSstage/CSstage-noise-optimization-capacitive.rst

Group exercise
==============

.. admonition:: important

   Please follow the instruction below (in the given order)
   
   #. Install `NGspice <https://ngspice.sourceforge.io/>`_
   #. Update your SLiCAP installation from `https://github.com/SLiCAP/SLiCAP_python <https://github.com/SLiCAP/SLiCAP_python>`_.
   
The source impedance of amplifier A1 consists of the parallel connection of the hearing loop receive coil and a damping resistor of :math:`10k\Omega`. The hearing loop receiver has an integrating characteristic; its idealized gain has been determined as :math:`\frac{62.4\times 10^3}{s}`.

#. Determine the show stopper value for the DIN-A weighted integrated noise at the output of the receive coil amplifier in Volts RMS.

#. Determine the contribution of the receive coil and its termination resistor to this weighted output noise. The DIN-A weighting curve can be modeled as a transfer function see `WiKi DIN-A weighting <https://en.wikipedia.org/wiki/A-weighting>`_. Please download the SLiCAP script `DIN_A.py <https://analog-electronics.tudelft.nl/EE4109-2024-2025/designExample/HearingLoop/SLiCAP/DIN_A.py>`_.

#. Consider the noise contribution of your feedback integrator circuit. Specify a budget for its noise contribution, and find a design limit (show-stopper) value for the resistance in this circuit.

#. Determine possible values of the transconductance :math:`g_m` and the input capacitance :math:`c_{iss}` of a MOS that can be used as input stage of the receive coil amplifier. To this end, consider the MOS as the main noise contributer of the amplifier and model the noise behavior as shown below. 

   The figure shows the use of an NMOS; it can be used for a PMOS changing the parameters

   .. image:: https://analog-electronics.tudelft.nl/EE4109-2024-2025/designExample/HearingLoop/SLiCAP/img/noise_ciss_gm_N.svg

#. Determine the values of the channel with :math:`W`, the channel length :math:`L`, and the quiescent operating current :math:`I_{DS}` of a MOS using the results of the previous exercise and the SLiCAP EKV NMOS noise model NM18_noise and LTspice (SLiCAP) symbol SLM_noise.

#. After all parameters have been defined, verify the noise with SLiCAP. 

#. Verify the result with LTspice.