Improvements since V1
21-10-2016
Top View
- All labels not properly represented were changed to fit into the pdf file.
- Net labels on the FMC component were changed (LA_XX instead of COMP_OUT) to stick to the FMC standard and allow port to port recognition.
- Guidelines for each regulator has been added.
- OUT_8, OUT_9 and BIP_OUT were transformed into ISOLATED_OUT0, ISOLATED_OUT1 and ISOLATED_CTRL respectively (to ease the understanding).
- SPI signals have been made more clear.
Power Supplies
- The sheet "Supply Stage" has been divided into "Positive Supplies", "Negative Supplies", "Sequencer" and "I2C, Onewire and Protection"
- To facilitate the test procedure, every voltage supplies have now their test points.
- 0 Ohm resistors were added for each voltage supplies.
- P7V0, N5V0 have been changed to P6V7 and N5V3 respectively. It allows protection diodes to fulfil their duty as the comparator model has changed.
- P6V7, N5V3 and N12V0 power supply circuits were recalculated and the surrounding components changed.
- The inductances on the former FMC version had two problems: their inductance and their saturation current.
Sequencer
- P12V0 to P12V0_VDD switch was changed from N_Mosfet to two Mosfet: one N_Mosfet with one P_Mosfet
- RESET_n pin was wrongly wired
- The threshold voltage was barely met with the resistors choice, now it is corrected
Input Stage
- Comparator LMH7324 has been replaced by the LMH7322 for availability and hysteresis reasons
- Protection voltage levels were changed according to the new comparators requirements
- As the hysteresis is built-in in the new comparator, the ADN4688 were removed
- A resistor divider has been added to handle -10V signals, compared to the-5V previously handled
- The high impedance (1 MOhm) rely now on the new resistor divider
- In order to guarantee optimal comparators protection, Schottky diodes were selected because of their reduced forward voltage
DAC
- GPIO and RST_n pins have been connected to VADJ according to the datasheet
I2C
- TCA9539PWR has replaced the TCA6416APWR, despite working fine the former model had only one pin for addressing and was not recommended for new designs
Output Stage
- MAX9122ESE was replaced by MAX9122EUE for availability reason
- Feedback lines should be labelled with "_N" at the end.
Layout
- The new comparator requires the heat-sink to be connected to the VEE which is N5V3 in this project.
- The FCS8 connector has been placed as far as possible of the LEMO and Leds to allow more space for plug/unplug manipulation.
- The new comparator has only 2 inputs (4 on the former model) but has bult-in hysteresis, thus new comparators replaced the former LVDS receiver.