AT9880

{
  "schema_version": 1,
  "type": "component",
  "slug": "at9880",
  "title": "AT9880",
  "brief": "ZHONGKEWEI GNSS Modules, QFN-40L-EP(5x5). Pinout extracted from the datasheet, KiCad symbol/footprint/3D.",
  "version": "0.1.0",
  "license": "CC-BY-SA-4.0",
  "tags": [
    "component",
    "iot-communication modules",
    "at9880"
  ],
  "component": {
    "mpn": "AT9880",
    "manufacturer": "ZHONGKEWEI",
    "package": "QFN-40L-EP(5x5)",
    "pin_count": 41,
    "category": "IoT/Communication Modules",
    "subcategory": "GNSS Modules",
    "datasheet": "https://datasheet.lcsc.com/datasheet/pdf/2070440b59e515adfd111dc1e919a714.pdf",
    "parts": {
      "symbol": "at9880.kicad_sym",
      "footprint": "at9880.kicad_mod",
      "model_3d": "at9880-etched.glb",
      "model_3d_plain": "at9880.glb",
      "model_3d_step": "at9880-etched.step",
      "model_3d_step_plain": "at9880.step",
      "lbr": "at9880.lbr"
    },
    "distributor_links": {},
    "pins": [
      {
        "number": "1",
        "name": "RF1",
        "type": "input",
        "description": "L1-band RF signal input (1561.098 MHz min / 1575.42 MHz typ / 1602 MHz max). DC voltage must not exceed 0.8V; AC-couple with a series capacitor if the external LNA output carries DC."
      },
      {
        "number": "2",
        "name": "GND",
        "type": "power_in",
        "description": "Ground."
      },
      {
        "number": "3",
        "name": "VDD_ANA",
        "type": "power_out",
        "description": "Analog LDO output. Bypass with 1uF decoupling capacitor close to the pin."
      },
      {
        "number": "4",
        "name": "VX_OUT",
        "type": "power_out",
        "description": "TCXO supply output (1.8V typ). Bypass with 1uF decoupling capacitor; feeds the external TCXO EN/VCC."
      },
      {
        "number": "5",
        "name": "XREF",
        "type": "input",
        "description": "Reference clock input from external 26 MHz TCXO. Accepts clipped-sine drive 0.5-1.5 Vpp."
      },
      {
        "number": "6",
        "name": "TST_RF",
        "type": "unconnected",
        "description": "Factory RF test port. Leave floating in normal application."
      },
      {
        "number": "7",
        "name": "VDD_BK",
        "type": "power_out",
        "description": "Backup-domain LDO output. Bypass with 1uF decoupling capacitor close to the pin."
      },
      {
        "number": "8",
        "name": "VBAT",
        "type": "power_in",
        "description": "Backup power input for the RTC/backup-RAM domain (1.4-3.6V, 3.3V typ). Keeps RTC time and backup RAM alive when the main supply is removed to enable warm/hot start."
      },
      {
        "number": "9",
        "name": "VDD_IO",
        "type": "power_in",
        "description": "Digital I/O supply input (2.7-3.6V, 3.3V typ). Also feeds the POR and antenna-detect circuits."
      },
      {
        "number": "10",
        "name": "ANT_BIAS",
        "type": "power_out",
        "description": "Active-antenna bias/feed with integrated current sensing for antenna open/short detection and short-circuit protection (short-protection trip 45-65 mA, typ 50 mA)."
      },
      {
        "number": "11",
        "name": "RTC_O",
        "type": "output",
        "description": "32.768 kHz RTC oscillator output. Connect the 32.768 kHz crystal (12.5 pF CL, ≤80 kΩ ESR) between RTC_O and RTC_I."
      },
      {
        "number": "12",
        "name": "RTC_I",
        "type": "input",
        "description": "32.768 kHz RTC oscillator input. Other terminal of the RTC crystal."
      },
      {
        "number": "13",
        "name": "GPIO2/TXD1",
        "type": "bidirectional",
        "description": "UART1 TXD (default) / general-purpose digital I/O."
      },
      {
        "number": "14",
        "name": "GPIO3/RXD1",
        "type": "bidirectional",
        "description": "UART1 RXD (default) / general-purpose digital I/O."
      },
      {
        "number": "15",
        "name": "Reserved",
        "type": "unconnected",
        "description": "Reserved. Leave floating when unused."
      },
      {
        "number": "16",
        "name": "Reserved",
        "type": "unconnected",
        "description": "Reserved. Leave floating when unused."
      },
      {
        "number": "17",
        "name": "nRST",
        "type": "input",
        "description": "Active-low external reset input, internal pull-up. Reset threshold VDD_IO ≈1.65V; internal nRESET released ~160 ms after nRST rises. Leave floating if unused."
      },
      {
        "number": "18",
        "name": "GPIO1/RXD0",
        "type": "bidirectional",
        "description": "UART0 RXD (default communication port) / general-purpose digital I/O."
      },
      {
        "number": "19",
        "name": "GPIO0/TXD0",
        "type": "bidirectional",
        "description": "UART0 TXD (default positioning output) / general-purpose digital I/O."
      },
      {
        "number": "20",
        "name": "GPIO27",
        "type": "bidirectional",
        "description": "General-purpose digital I/O (Vih ≥ 0.8·VDD_IO, Vil ≤ 0.2·VDD_IO, Voh ≥ VDD_IO−0.4V, Vol ≤ 0.4V; internal 80 kΩ pull-up/pull-down programmable)."
      },
      {
        "number": "21",
        "name": "DX_IN",
        "type": "power_in",
        "description": "Internal DCDC converter input (typically tied to 3.3V main supply). Decouple with a 2.2uF cap; the DCDC steps 3.3V down for the internal core LDO."
      },
      {
        "number": "22",
        "name": "DX_OUT",
        "type": "power_out",
        "description": "Internal DCDC switching-node/output. Connect the DCDC inductor (4.7uH) and 10uF output cap; the resulting rail feeds VCORE."
      },
      {
        "number": "23",
        "name": "VCORE",
        "type": "power_in",
        "description": "Core LDO input (1.2V min, 3.6V max). Normally sourced from DX_OUT via the DCDC, but may be driven from an external supply."
      },
      {
        "number": "24",
        "name": "VDD_BB",
        "type": "power_out",
        "description": "Digital core LDO output (1.0V typ). Bypass with 2.2uF decoupling capacitor close to the pin."
      },
      {
        "number": "25",
        "name": "GPIO22",
        "type": "bidirectional",
        "description": "General-purpose digital I/O; default function is 1PPS timing output."
      },
      {
        "number": "26",
        "name": "Reserved",
        "type": "unconnected",
        "description": "Reserved. Leave floating when unused."
      },
      {
        "number": "27",
        "name": "Reserved",
        "type": "unconnected",
        "description": "Reserved. Leave floating when unused."
      },
      {
        "number": "28",
        "name": "Reserved",
        "type": "unconnected",
        "description": "Factory test port. Leave floating when unused."
      },
      {
        "number": "29",
        "name": "ON_OFF",
        "type": "input",
        "description": "Shutdown/wake control input; internal pull-up. Drive low to enter sleep mode (~50 uA); leave floating if unused."
      },
      {
        "number": "30",
        "name": "GPIO4",
        "type": "bidirectional",
        "description": "General-purpose digital I/O. Leave floating when unused."
      },
      {
        "number": "31",
        "name": "GPIO5",
        "type": "bidirectional",
        "description": "General-purpose digital I/O. Leave floating when unused."
      },
      {
        "number": "32",
        "name": "GPIO8",
        "type": "bidirectional",
        "description": "General-purpose digital I/O. Leave floating when unused."
      },
      {
        "number": "33",
        "name": "GPIO7",
        "type": "bidirectional",
        "description": "General-purpose digital I/O. Leave floating when unused."
      },
      {
        "number": "34",
        "name": "GPIO6",
        "type": "bidirectional",
        "description": "General-purpose digital I/O. Leave floating when unused."
      },
      {
        "number": "35",
        "name": "GPIO10",
        "type": "bidirectional",
        "description": "General-purpose digital I/O. Leave floating when unused."
      },
      {
        "number": "36",
        "name": "GPIO9",
        "type": "bidirectional",
        "description": "General-purpose digital I/O. Leave floating when unused."
      },
      {
        "number": "37",
        "name": "DVDD",
        "type": "power_out",
        "description": "PLL LDO output. Bypass with 1uF decoupling capacitor close to the pin."
      },
      {
        "number": "38",
        "name": "GND",
        "type": "power_in",
        "description": "Ground; also acts as RF isolation pin between RF1 and RF2 - tie directly to PCB ground plane with multiple vias."
      },
      {
        "number": "39",
        "name": "RF2",
        "type": "input",
        "description": "L5-band RF signal input (1176.45 MHz). DC voltage must not exceed 0.8V; AC-couple with a series capacitor if the external LNA output carries DC."
      },
      {
        "number": "40",
        "name": "GND",
        "type": "power_in",
        "description": "Ground."
      },
      {
        "number": "EP",
        "name": "GND",
        "type": "power_in",
        "description": "Exposed thermal pad on package underside. Must be soldered directly to the PCB ground plane with a full via array for thermal and electrical grounding."
      }
    ],
    "provenance": {
      "extractor": "ds2sf",
      "datasheet": {
        "url": "https://datasheet.lcsc.com/datasheet/pdf/2070440b59e515adfd111dc1e919a714.pdf",
        "pages": 16,
        "sha256": "97d93eb7c809245b",
        "source_tier": "lcsc"
      },
      "cad": "KiCad official (CC-BY-SA 4.0)",
      "pins": {
        "total": 41,
        "described": 41,
        "cites_pages": true,
        "refuses_to_fabricate": true
      }
    },
    "viewers": {
      "symbol": "viewers/symbol.html",
      "footprint": "viewers/footprint.html"
    },
    "models_3d": [
      {
        "file": "at9880.step",
        "role": "plain",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          5,
          5,
          0.77
        ],
        "zmin_mm": 0,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "8f37bc7a9aab4742c34f137d9822c0352acc227532830034555744338483cdfc",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      },
      {
        "file": "at9880-etched.step",
        "role": "eda",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          5,
          5,
          0.77
        ],
        "zmin_mm": 0,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "01ba4989ecedd13989880d3c290904dbaf7d340c2c5030cf4fde292e25ae78d8",
        "checked": "2026-10-07",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      }
    ]
  },
  "metadata": {
    "specs": {
      "Manufacturer": "ZHONGKEWEI",
      "Package": "QFN-40L-EP(5x5)",
      "Category": "IoT/Communication Modules",
      "Pins": "41"
    }
  },
  "variants": [],
  "sections": [
    "hero",
    "viewers",
    "readme",
    "breadcrumbs",
    "info"
  ],
  "discovery_triggers": [
    "at9880"
  ],
  "discovery_pitch": "AT9880 (ZHONGKEWEI) component page with datasheet-verified CAD.",
  "author": {
    "name": "Ray"
  },
  "dependencies": {},
  "hero": {
    "type": "image",
    "path": "docs/hero.png"
  },
  "files": [
    "page.json",
    "README.md",
    "at9880.kicad_sym",
    "at9880.kicad_mod",
    "at9880.glb",
    "at9880.step",
    "at9880.lbr",
    "docs/hero.png",
    "docs/at9880-datasheet.pdf",
    "viewers/symbol.html",
    "viewers/footprint.html"
  ],
  "visibility": {
    "public": true
  },
  "updated_at": "2026-09-24T17:15:17.902Z"
}