component
SI522
Public Unreviewedby Ray
Nanjing Zhongke Microelectronics RFID ICs, QFN-32-EP(5x5). Datasheet-verified pinout, KiCad symbol/footprint/3D.
3D Model
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Symbol & Footprint
Schematic Symbol
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PCB Footprint
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Datasheet
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README
markdownSI522
Nanjing Zhongke Microelectronics · RFID ICs · QFN-32-EP(5x5)
SI522 from Nanjing Zhongke Microelectronics, in a QFN-32-EP(5x5). Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.
Pinout
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | SDI | input | Serial Data Interface (2-wire) enable input. Held high (with EA) to select the 2-wire serial host interface after reset; part of the interface auto-detect strap set. |
| 2 | PVDD | power_in | Pin (pad-driver) power supply, 2.5 V to 3.6 V (recommended 3.3 V). PVDD must be less than or equal to DVDD. |
| 3 | DVDD | power_in | Digital core power supply, 2.5 V to 3.6 V (typ. 3.3 V). Must be tied to the same rail as VDDA and TVDD per note 1 in 表 4-2. |
| 4 | DVSS | power_in | Digital ground reference (0 V). The QFN exposed thermal pad on the package underside must be connected to DVSS. |
| 5 | PVSS | power_in | Pin (pad-driver) ground reference (0 V) for the PVDD domain. |
| 6 | NRSTPD | input | Reset and hard power-down input. Driving low enters hard power-down: internal current sinks and oscillator are disabled and the input pins are disconnected. A rising edge releases reset. |
| 7 | MFIN | input | Factory/test input (measurement input). Not used in normal operation. |
| 8 | MFOUT | output | Factory/test output (measurement output). Not used in normal operation. |
| 9 | SVDD | power_in | Supply for the MFIN/MFOUT test-pin pad drivers, 2.5 V to 3.6 V (typ. 3.3 V). |
| 10 | TVSS | power_in | Transmitter output-stage 1 ground return (high-current). Tie to the low-impedance analog ground plane close to the antenna matching network. |
| 11 | TX1 | output | Transmitter 1 output: 13.56 MHz modulated carrier driver output for the reader antenna (differential with TX2). |
| 12 | TVDD | power_in | Transmitter supply for the TX1 and TX2 output stages, 2.5 V to 3.6 V (typ. 3.3 V). Sets the drive amplitude into the antenna. |
| 13 | TX2 | output | Transmitter 2 output: 13.56 MHz modulated carrier driver output for the reader antenna (differential with TX1). |
| 14 | TVSS | power_in | Transmitter output-stage 2 ground return (high-current). Tie to the low-impedance analog ground plane close to the antenna matching network. |
| 15 | AVDD | power_in | Analog supply for the receiver and reference circuitry, 2.5 V to 3.6 V (typ. 3.3 V). IDDA is 2.9 mA typ. with receiver active, 0.8 mA typ. with RcvOff=1. |
| 16 | VMID | passive | Internal analog reference voltage node. Decouple with an external capacitor to AVSS; do not load externally. |
| 17 | RX | input | Receiver RF input from the antenna matching / receive network. Feeds the on-chip demodulator/decoder. |
| 18 | AVSS | power_in | Analog ground reference (0 V) for the AVDD/VMID/RX domain. |
| 19 | AUX1 | output | Auxiliary analog/digital test output for factory characterization. Leave unconnected in normal use. |
| 20 | AUX2 | output | Auxiliary analog/digital test output for factory characterization. Leave unconnected in normal use. |
| 21 | OSCIN | input | Crystal oscillator inverting amplifier input; also accepts an externally generated 27.12 MHz clock reference (fclk = 27.12 MHz). |
| 22 | OSCOUT | output | Crystal oscillator inverting amplifier output. Connect to the second terminal of the 27.12 MHz crystal; leave floating when driving OSCIN from an external clock. |
| 23 | IRQ | output | Interrupt request output to the host controller. Asserts to indicate an interrupt event; polarity/behavior configured via the interrupt registers. |
| 24 | SD/NSS/RX | bidirectional | Multiplexed host-interface pin. As SD: bidirectional data line for the 2-wire serial interface. As NSS: SPI chip-select input (active-low). As RX: UART data input from host to Si522. |
| 25 | D1/ADR_5 | bidirectional | Multiplexed. D1: test port I/O (SPI/UART modes leave it unused, tie per app note). ADR_5: 2-wire serial address bit 5 input when the 2-wire interface is selected. |
| 26 | D2/ADR_4 | bidirectional | Multiplexed. D2: test port I/O (unused in SPI/UART modes). ADR_4: 2-wire serial address bit 4 input. |
| 27 | D3/ADR_3 | bidirectional | Multiplexed. D3: test port I/O (unused in SPI/UART modes). ADR_3: 2-wire serial address bit 3 input. |
| 28 | D4/ADR_2 | bidirectional | Multiplexed. D4: test port I/O (unused in SPI/UART modes). ADR_2: 2-wire serial address bit 2 input. |
| 29 | D5/ADR_1/SCK/DTRQ | bidirectional | Multiplexed. SCK: SPI serial clock input from the host (up to 10 MHz). DTRQ: UART request-to-send output to the host. ADR_1: 2-wire address bit 1 input. D5: factory test I/O. |
| 30 | D6/ADR_0/MOSI/MX | bidirectional | Multiplexed. MOSI: SPI master-out/slave-in data input. MX: UART data output from Si522 to host. ADR_0: 2-wire address bit 0 input. D6: factory test I/O. |
| 31 | D7/SC/MISO/TX | bidirectional | Multiplexed. MISO: SPI master-in/slave-out data output. TX: UART data output from Si522 to host. SC: 2-wire serial clock I/O. D7: factory test I/O. |
| 32 | EA | input | External address input strap for the 2-wire serial interface. Also part of the interface auto-detect: EA=0 with SDI=0 selects UART, EA=1 with SDI=0 selects SPI, and EA is used as the encoded address bit when the 2-wire interface is selected. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Nanjing Zhongke Microelectronics |
| Package | QFN-32-EP(5x5) |
| Category | RF And Wireless |
| Pins | 32 |
CAD (KiCad official)
- Symbol:
SI522 - Footprint:
Package_DFN_QFN:QFN-32-1EP_5x5mm_P0.5mm_EP3.3x3.3mm - 3D model: QFN-32-EP(5x5) (KiCad packages3D, STEP)
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Nanjing Zhongke Microelectronics datasheet (38 pp, sha256
94296fadef3b08d9, retrieved 2026-08-17, tier: lcsc) - Datasheet language: Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
- Extractor:
ds2sf(Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate. - CAD: KiCad official libraries (CC-BY-SA 4.0).