S4g
===

.. _s4g_description:

Description
-----------

The S4g is a 4 channel DC current source. Each channel is controlled by the same 18-bit DACs (Digital to Analog Converters).

.. figure:: ./figures/FrontS4g.png
    :height: 600px
    :align: left
    :alt: An S4g current module.

On the front of each S4g module you find:

- **4 x SMA**: DC current source with software-selectable range: ±50 mA, ±25 mA, +50 mA, 18-bit resolution, 40 Ω output impedance.
- **4 x MCX**: Voltage monitor for each channel.
- **4 x LED**: To indicate that the current source is clipping to its compliance voltage.


Specifications
--------------

Output characteristics
^^^^^^^^^^^^^^^^^^^^^^

+-----------------------------+----------------------+-----------------------+----------------------+
| Parameter                   | Value                | Units                 | Conditions           |
+=============================+======================+=======================+======================+
| Analog channels             | 4                    |                       | SMA connectors       | 
+-----------------------------+----------------------+-----------------------+----------------------+
| Monitor channels            | 4                    |                       | MCX connectors       | 
+-----------------------------+----------------------+-----------------------+----------------------+
| Range                       | ±50, ±25, +50        | mA                    |                      |   
+-----------------------------+----------------------+-----------------------+----------------------+
| Compliance voltage          | ±3.5                 | V                     |                      |
+-----------------------------+----------------------+-----------------------+----------------------+

Static performance
******************

+----------------------------------+----------------------+-----------------------+----------------------+
| Parameter                        | Value                | Units                 | Conditions           |
+==================================+======================+=======================+======================+
| Resolution                       | 18                   | bit                   |                      |
+----------------------------------+----------------------+-----------------------+----------------------+
| Differential Non-Linearity (DNL) | ±0.2                 | LSB                   | Typical value        |
+----------------------------------+----------------------+-----------------------+----------------------+
| Integral Non-Linearity (INL)     | ±0.5                 | LSB                   | Typical value        |
+----------------------------------+----------------------+-----------------------+----------------------+

Dynamic performance
*******************

+-----------------------------+----------------------+-----------------------+----------------------+
| Parameter                   | Value                | Units                 | Conditions           |
+=============================+======================+=======+===============+======================+
| Noise                       | <2.5                 | nA/√Hz @ 10 kHz       | Measured @ +50 mA    |
|                             +----------------------+-----------------------+ into 50 Ω with       |
|                             | <0.8                 | nA/√Hz @ 1 kHz        | ±50 mA range         |
+-----------------------------+----------------------+-----------------------+----------------------+
| Drift                       | 2.5                  | ppm/°C of full scale  |                      |
+-----------------------------+----------------------+-----------------------+----------------------+

Miscellaneous
^^^^^^^^^^^^^

+-----------------------------+----------------------+-----------------------+----------------------+
| Parameter                   | Value                | Units                 | Conditions           |
+=============================+======================+=======+===============+======================+
| Power consumption           | 1.625                | W                     | No load              |
|                             +----------------------+-----------------------+----------------------+
|                             | 2.6                  | W                     | Full load            |
+-----------------------------+----------------------+-----------------------+----------------------+
| Dimensions                  | 35.3 x 128.7 x 182   | mm³                   |                      |
+-----------------------------+----------------------+-----------------------+----------------------+
| Weight                      | 0.286                | kg                    |                      |
+-----------------------------+----------------------+-----------------------+----------------------+