.. _current_measurement_box_rev03:

Current Measurement Box Rev03
=============================

Overview
--------

.. figure:: currentmeasurementbox_rev03_externalthreads.jpg
   :alt: Current measurement box Rev03
   :align: center
   :width: 800px

Rev03 is the latest revision of the current measurement box.
The schematic is built around four identical measurement channels.
Each channel uses a Sensitec CAS50xxSRA or CAS50xxKRA current sensor and a THS4521 fully differential amplifier stage.

Changes from Rev02
------------------

- Input and output terminals changed to Wuerth REDCUBE press-fit terminals for M3 ring shoes. 
- Input supply range in the schematic is extended to 7 V to 65 V.
- The power supply now generates an intermediate 6.5 V rail and a clean 5.10 V VCC+ rail.
- Differential output filtering is populated with 5.6 nF differential capacitance and 470 pF common-mode capacitors.

Interface
---------

**Inputs:**

- Supply voltage VIN: 7 V to 65 V via Samtec IPL1-102-02-L-D-K.
- Alternative VIN connector footprint: TSW-102-07-F-S.
- Sensor current path per channel through REDCUBE press-fit terminals for M3 ring shoes, rated for 130 A.

  - Initially, the external-thread `Wuerth 7461094 <https://www.we-online.com/components/products/datasheet/7461094.pdf>`_ terminal was used.
  - Due to production issues during press-fit assembly, it was changed to the internal-thread `Wuerth 7461093 <https://www.we-online.com/components/products/datasheet/7461093.pdf>`_ terminal.

**Outputs:**

- 4 fully differential voltage outputs via RJ45.

.. figure:: currentmeasurementbox_rev03_internalthreads.jpg
   :alt: Current measurement box Rev03 with internal-thread terminals
   :align: center
   :width: 800px

   Rev03 with internal-thread REDCUBE terminals 7461093.

Functionality and Specifications
--------------------------------

.. list-table::
   :widths: 30 70
   :header-rows: 1

   * - Parameter
     - Description
   * - VIN
     - 7 V to 65 V
   * - Intermediate supply
     - 6.5 V generated by TPSM365R6 buck converter
   * - VCC+ Supply
     - 5.10 V generated by TPS7A4700 LDO
   * - Reference / output common-mode
     - 2.5 V generated by REF35250QDBVR
   * - Number of channels
     - 4
   * - Current sensor
     - Sensitec CAS50xxSRA/CAS50xxKRA
   * - Amplifier
     - THS4521 fully differential amplifier, gain = 2
   * - Input current connection
     - REDCUBE press-fit terminals
   * - Output connector
     - RJ45 for fully differential output pairs
   * - Output filter
     - R13/R15 = 49.9 Ohm, C18 = 5.6 nF, C16/C20 = 470 pF
   * - Filter cutoff
     - 273 kHz 

Supported Sensors
-----------------

Rev03 supports all current transducers listed in :ref:`current_measurement_box_supported_sensors`, including CAS5075KRA-KH.

Schematic
---------

* :download:`Schematic Rev03 <SCH_Strommessplatine_Default_Rev03.pdf>`

Known Issues
------------

No known issues are documented yet.