Rev A Locked Architecture Details

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cigz75

Run AD5940 datasheet limits review only.
Do not modify schematic wiring.
Do not add components.
Do not change nets.
Review the AD5940 placeholder against datasheet/application-circuit requirements and identify what must be locked before PCB layout.
Check:
  1. Rail requirements:
  • AVDD valid voltage range
  • DVDD valid voltage range
  • IOVDD / digital I/O rail requirement
  • REG_1V8 role
  • whether DVDD_AD5940 may remain tied to MCU_3V3: yes/no/uncertain
  • whether separate 1.8 V rail placeholder is required: yes/no/uncertain
  1. SPI/logic compatibility:
  • whether STM32L552 3.3 V SPI can directly connect to AD5940: yes/no/uncertain
  • whether level shifting may be required: yes/no/uncertain
  1. BioZ/EIS pins:
  • map placeholder nets to likely AD5940 pins/functions:
    AD5940_I_PLUS_PATH
    AD5940_I_MINUS_PATH
    AD5940_V_PLUS_PATH
    AD5940_V_MINUS_PATH
    AD5940_CURRENT_SENSE_P
    AD5940_CURRENT_SENSE_N
    AD5940_EXC_MON
    AD5940_AIN_MON
  1. Application-circuit blockers:
  • required external references
  • required RTIA/RLOAD/RCAL components
  • required clock/crystal if any
  • required decoupling not already represented
  • required reset/interrupt/control pins
  1. Pre-layout decision:
    Choose one:
    A. Keep AD5940 as placeholder only
    B. Add separate 1.8 V LDO placeholder
    C. Add level-shifter placeholder only
    D. Split DVDD_AD5940 from MCU_3V3
    E. Need human datasheet review before schematic changes
Report only:
  • AD5940 rail blockers
  • SPI/logic blockers
  • missing application-circuit components
  • recommended next schematic action
  • whether current AD5940 section is safe for PCB layout: yes/no

flux

I’ll run a read-only AD5940 datasheet-limits review against the current placeholder section, check rails, SPI logic, pin-role mapping, and application-circuit gaps, then report only the blockers and next action.
Worked for 1 min 10 sec
Thought for 4 sec
1/4 Read current AD5940 placeholder connectivity, rails, and support components in the schematic

Read current AD5940 placeholder connectivity, rails, and support components in the schematic

Extract AD5940 rail, I/O, and application-circuit requirements from datasheet/application references

Map current placeholder nets to likely AD5940 functions and identify blockers

Report only the requested AD5940 datasheet-limits conclusions

Accessed knowledge for the next task.
Thought for 8 sec
Read ad5940.html.
Read an-1557.html.
Read pdf.html.
Reading schematic details for U_AD5940, U_MCU_STM32L552, U_LDO_ANALOG_AVDD and 5 more.
Thought for a moment

flux

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MCU GPIO Assignment Draft
Draft MCU functional net assignment for EchoS Bank Rev A.
U_MCU_STM32L552 controls one AD5940 and four ADG1406-family muxes.
AD5940 SPI/control nets: SPI_SCLK -> AD5940 SPI clock SPI_MOSI -> AD5940 SPI MOSI SPI_MISO -> AD5940 SPI MISO AD5940_CS_N -> AD5940 chip select AD5940_RST_N -> AD5940 reset AD5940_INT_N -> AD5940 interrupt input to MCU
Mux shared address nets: MUX_A0 -> all four mux A0 pins MUX_A1 -> all four mux A1 pins MUX_A2 -> all four mux A2 pins MUX_A3 -> all four mux A3 pins
Mux independent enable nets: MUX_I_PLUS_EN MUX_I_MINUS_EN MUX_V_PLUS_EN MUX_V_MINUS_EN
Other MCU interfaces: I2C_SCL / I2C_SDA -> temperature sensors USB_DP / USB_DM -> USB-C device interface to Mac AUX_ADC_IN / AUX_GPIO -> optional auxiliary header
Rules:
  • This is a draft functional assignment only.
  • Do not claim final STM32L552 package pins yet.
  • Final GPIO package pin mapping must be checked against the selected STM32L552 package and board layout.
  • Keep SPI and mux control routing away from analog sense/calibration region.
  • Do not modify schematic wiring.
  • Do not add components.
  • Do not modify calibration bank.
  • Do not modify mux map.