Access Reader Design
Table
| Net | Source / Destination | Notes |
|---|---|---|
VIN_DC_RAW | DC terminal input | 9-32 V input before protection. |
VIN_DC_PROT | After fuse/TVS/reverse/EMI | Feeds LMR16020. |
5V_DC_PRE_OR | LMR16020 output | Must not directly connect to AG9905 output. |
5V_POE_PRE_OR | AG9905-MTB 5 V output | Must not directly connect to LMR16020 output. |
5V_SYS | OR-ing / mux output | Common 5 V rail after reverse blocking. |
3V3_SYS | 3.3 V buck output | Logic/RF/Ethernet rail. |
SPI_SCK, SPI_MOSI, SPI_MISO | ESP32-S3, CLRC663, W5500 | Shared bus; confirm MISO tri-state. |
W5500_CS, W5500_INT, W5500_RST | ESP32-S3 to W5500 | Ethernet is populated in prototype. |
USB_DP, USB_DN | ESP32-S3 native USB | Service/programming. |
Table
| Function | Required Part / Class | Prototype Status |
|---|---|---|
| PoE 5 V | AG9905-MTB | Populate |
| Ethernet/PoE connector | RJ45 MagJack compatible with W5500 and PoE path | Populate |
| DC buck controller/regulator | LMR16020 | Populate |
| DC buck inductor | Datasheet-sized for 5 V rail peak current | Populate |
| DC buck rectifier/diode if required | Datasheet topology-specific | Populate |
| DC buck feedback resistors | Set 5 V output; tolerance suitable for OR-ing | Populate |
| DC input TVS/fuse/reverse protection | Rated for 9-32 V system and expected surges | Populate |
| 5 V source OR-ing | Reverse-blocking ideal diode / priority mux / equivalent FET solution | Populate |
| Post-OR bulk capacitance | Sized for load transients and source startup limits | Populate |
Table
| Function | Required Part / Class | Prototype Status |
|---|---|---|
| Wi-Fi/BLE MCU | ESP32-S3-WROOM-1-N16R2 | Populate |
| Ethernet controller | W5500 | Populate |
| Ethernet clock/support | W5500 crystal/oscillator and passives as datasheet requires | Populate |
| Ethernet ESD/termination | Protection and Bob Smith/termination as required by MagJack/reference design | Populate |
| Native USB service | USB connector, CC/ESD if USB-C, or matching USB connector support | Populate |
Table
| Subsystem | Prototype Status |
|---|---|
| ESP32-S3 boot/reset/native USB/debug | Populate |
| 5 V to 3.3 V regulator | Populate |
| W5500 + RJ45/MagJack Ethernet | Populate |
| AG9905-MTB PoE | Populate |
| LMR16020 9-32 V DC buck | Populate |
| OR-ing / priority power merge | Populate |
| CLRC663 NFC front-end | Populate |
| EM4095 LF front-end | Populate |
| GM861 QR module connector and power switch | Populate |
| RS-485 interface/protection | Populate |
| Wiegand open-drain drivers/protection | Populate |
| Two relay outputs and flyback/suppression | Populate |
| Two opto/digital inputs and tamper | Populate |
| PCF8563 RTC + CR1220 holder | Populate |
| WS2812/status LED and buzzer | Populate |
Exclude from BOM, Exclude from PCB, Exclude from Pick & Place, or DNP notes for the first prototype.5V_SYS and 3V3_SYS have accessible test points and local bulk capacitance.Purpose
Required Nets
Power Branch BOM Gate
Ethernet/Wi-Fi BOM Gate
Full-System Population Gate
Manual Connectivity Pass Criteria