CH438Q

{
  "schema_version": 1,
  "type": "component",
  "slug": "ch438q",
  "title": "CH438Q",
  "brief": "WCH(Jiangsu Qin Heng) RS232 ICs, LQFP-44(10x10). Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.",
  "version": "0.1.0",
  "license": "CC-BY-SA-4.0",
  "tags": [
    "component",
    "interface ics",
    "ch438q",
    "factory-2.0.0",
    "extractor-text"
  ],
  "component": {
    "mpn": "CH438Q",
    "manufacturer": "WCH(Jiangsu Qin Heng)",
    "package": "LQFP-44(10x10)",
    "pin_count": 44,
    "category": "Interface ICs",
    "subcategory": "RS232 ICs",
    "datasheet": "https://datasheet.lcsc.com/datasheet/pdf/1fbe2751991eaf39cd5a29ebd9c3a74d.pdf",
    "parts": {
      "symbol": "ch438q.kicad_sym",
      "footprint": "ch438q.kicad_mod",
      "model_3d": "ch438q-hero.glb",
      "model_3d_plain": "ch438q-etched.glb",
      "model_3d_step": "ch438q-etched.step",
      "model_3d_step_plain": "ch438q.step",
      "lbr": "ch438q.lbr"
    },
    "distributor_links": {
      "lcsc": "C100039"
    },
    "distributor_check": {
      "checked_at": "2026-10-23T03:32:44Z",
      "source": "Component Ocean /api/assign-pns",
      "digikey": {
        "pn": null,
        "status": "no match"
      },
      "mouser": {
        "pn": null,
        "status": "no match"
      }
    },
    "pins": [
      {
        "number": "1",
        "name": "WR#",
        "type": "input",
        "description": "Write strobe input in parallel port mode, active at low level."
      },
      {
        "number": "2",
        "name": "VCC",
        "type": "power_in",
        "description": "Positive power terminal; supply 3.3V to 5.3V (5V typ)."
      },
      {
        "number": "3",
        "name": "GND",
        "type": "power_in",
        "description": "Common grounding end."
      },
      {
        "number": "4",
        "name": "A6/ALE",
        "type": "input",
        "description": "Address line A6 in direct address mode; address latch enable input in multiplexed address mode, active at high level."
      },
      {
        "number": "5",
        "name": "A5",
        "type": "input",
        "description": "Address line input in direct address mode."
      },
      {
        "number": "6",
        "name": "A4",
        "type": "input",
        "description": "Address line input in direct address mode."
      },
      {
        "number": "7",
        "name": "A3",
        "type": "input",
        "description": "Address line input in direct address mode."
      },
      {
        "number": "8",
        "name": "A2",
        "type": "input",
        "description": "Address line input in direct address mode."
      },
      {
        "number": "9",
        "name": "A1",
        "type": "input",
        "description": "Address line input in direct address mode."
      },
      {
        "number": "10",
        "name": "A0",
        "type": "input",
        "description": "Address line input in direct address mode."
      },
      {
        "number": "11",
        "name": "RXD4",
        "type": "input",
        "description": "UART4 asynchronous serial data input with built-in weak pull-up resistor."
      },
      {
        "number": "12",
        "name": "TXD4",
        "type": "output",
        "description": "UART4 asynchronous serial data output."
      },
      {
        "number": "13",
        "name": "TXD3",
        "type": "output",
        "description": "UART3 asynchronous serial data output."
      },
      {
        "number": "14",
        "name": "GND",
        "type": "power_in",
        "description": "Common grounding end."
      },
      {
        "number": "15",
        "name": "RXD3",
        "type": "input",
        "description": "UART3 asynchronous serial data input with built-in weak pull-up resistor."
      },
      {
        "number": "16",
        "name": "VCC",
        "type": "power_in",
        "description": "Positive power terminal; supply 3.3V to 5.3V (5V typ)."
      },
      {
        "number": "17",
        "name": "GND",
        "type": "power_in",
        "description": "Common grounding end."
      },
      {
        "number": "18",
        "name": "XI",
        "type": "input",
        "description": "Crystal oscillator input, connect external crystal and oscillation capacitor or drive external clock (0.9216MHz to 32MHz)."
      },
      {
        "number": "19",
        "name": "XO",
        "type": "output",
        "description": "Reverse-phase crystal oscillator output, connect external crystal and oscillation capacitor to ground."
      },
      {
        "number": "20",
        "name": "RXD2",
        "type": "input",
        "description": "UART2 asynchronous serial data input with built-in weak pull-up resistor."
      },
      {
        "number": "21",
        "name": "TXD2",
        "type": "output",
        "description": "UART2 asynchronous serial data output."
      },
      {
        "number": "22",
        "name": "TXD1",
        "type": "output",
        "description": "UART1 asynchronous serial data output."
      },
      {
        "number": "23",
        "name": "RXD1",
        "type": "input",
        "description": "UART1 asynchronous serial data input with built-in weak pull-up resistor."
      },
      {
        "number": "24",
        "name": "TXD5",
        "type": "output",
        "description": "UART5 asynchronous serial data output."
      },
      {
        "number": "25",
        "name": "RXD5",
        "type": "input",
        "description": "UART5 asynchronous serial data input with built-in weak pull-up resistor."
      },
      {
        "number": "26",
        "name": "TXD6",
        "type": "output",
        "description": "UART6 asynchronous serial data output."
      },
      {
        "number": "27",
        "name": "RXD6",
        "type": "input",
        "description": "UART6 asynchronous serial data input with built-in weak pull-up resistor."
      },
      {
        "number": "28",
        "name": "TXD7",
        "type": "output",
        "description": "UART7 asynchronous serial data output."
      },
      {
        "number": "29",
        "name": "RXD7",
        "type": "input",
        "description": "UART7 asynchronous serial data input with built-in weak pull-up resistor."
      },
      {
        "number": "30",
        "name": "TXD0",
        "type": "output",
        "description": "UART0 asynchronous serial data output."
      },
      {
        "number": "31",
        "name": "RXD0",
        "type": "input",
        "description": "UART0 asynchronous serial data input with built-in weak pull-up resistor."
      },
      {
        "number": "32",
        "name": "INT",
        "type": "output",
        "description": "Open-drain interrupt request output, active at low level, external pull-up resistor may be required."
      },
      {
        "number": "33",
        "name": "RST#",
        "type": "input",
        "description": "External manual reset input, active at low level, built-in weak pull-down resistor."
      },
      {
        "number": "34",
        "name": "D7",
        "type": "bidirectional",
        "description": "Bit 7 of the 8-bit parallel bidirectional three-state data bus; address/data multiplexed in multiplexed address mode."
      },
      {
        "number": "35",
        "name": "D6",
        "type": "bidirectional",
        "description": "Bit 6 of the 8-bit parallel bidirectional three-state data bus; address/data multiplexed in multiplexed address mode."
      },
      {
        "number": "36",
        "name": "D5",
        "type": "bidirectional",
        "description": "Bit 5 of the 8-bit parallel bidirectional three-state data bus; address/data multiplexed in multiplexed address mode."
      },
      {
        "number": "37",
        "name": "D4",
        "type": "bidirectional",
        "description": "Bit 4 of the 8-bit parallel bidirectional three-state data bus; address/data multiplexed in multiplexed address mode."
      },
      {
        "number": "38",
        "name": "D3",
        "type": "bidirectional",
        "description": "Bit 3 of the 8-bit parallel bidirectional three-state data bus; address/data multiplexed in multiplexed address mode."
      },
      {
        "number": "39",
        "name": "D2",
        "type": "bidirectional",
        "description": "Bit 2 of the 8-bit parallel bidirectional three-state data bus; address/data multiplexed in multiplexed address mode."
      },
      {
        "number": "40",
        "name": "D1",
        "type": "bidirectional",
        "description": "Bit 1 of the 8-bit parallel bidirectional three-state data bus; address/data multiplexed in multiplexed address mode."
      },
      {
        "number": "41",
        "name": "D0",
        "type": "bidirectional",
        "description": "Bit 0 of the 8-bit parallel bidirectional three-state data bus; address/data multiplexed in multiplexed address mode."
      },
      {
        "number": "42",
        "name": "AMOD",
        "type": "input",
        "description": "Address input mode selection: low level is direct address mode, high level is multiplexed address mode."
      },
      {
        "number": "43",
        "name": "CS#",
        "type": "input",
        "description": "Chip selection control input in parallel port mode, active at low level."
      },
      {
        "number": "44",
        "name": "RD#",
        "type": "input",
        "description": "Read strobe input in parallel port mode, active at low level."
      }
    ],
    "provenance": {
      "extractor": "extract_pins 0.3",
      "factory_chain": {
        "factory": "2.0.0",
        "extractor": "extract_pins 0.3",
        "primary_model": "claude-sonnet-5-5",
        "primary_mode": "text+vision",
        "consensus_model": "claude-opus-5-5",
        "consensus": "agreed",
        "guards": "pin_guards 0.1: passed",
        "guard_notes": [
          "extractor flagged: Pin numbers were read from the CH438Q package drawing on page 2, because the text tables give only C; The datasheet has no CH438Q-specific description for each pin. Descriptions are borrowed from the CH",
          "vision extraction: provenance cannot be text-verified; needs consensus"
        ],
        "pages_sent": 14,
        "cost_usd": 0.6273,
        "at": "2026-10-23T03:32:19"
      },
      "datasheet": {
        "url": "https://datasheet.lcsc.com/datasheet/pdf/1fbe2751991eaf39cd5a29ebd9c3a74d.pdf",
        "pages": 14,
        "sha256": "99b5378163fd173a",
        "source_tier": "lcsc"
      },
      "cad": "KiCad official (CC-BY-SA 4.0)",
      "pins": {
        "total": 44,
        "described": 44,
        "cites_pages": true,
        "refuses_to_fabricate": true
      }
    },
    "viewers": {
      "symbol": "viewers/symbol.html",
      "footprint": "viewers/footprint.html"
    },
    "models_3d": [
      {
        "file": "ch438q.step",
        "role": "plain",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
          12,
          12,
          1.5
        ],
        "zmin_mm": 0,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "81aae6270b5c742bed79a8a35e9adf7fbed97c42e341e6b25ab20c1783b93b5d",
        "checked": "2026-10-23",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      },
      {
        "file": "ch438q-etched.step",
        "role": "eda",
        "up": "Z",
        "units": "mm",
        "origin": "footprint origin = pad-pattern centre",
        "seat": "z = 0",
        "extents_mm": [
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          1.5
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        "zmin_mm": 0,
        "centre_offset_mm": 0,
        "footprint_binding": "identity",
        "sha256": "55720896cfe2996a6a946422b1bda8706a231075d3306a48ff603de2b3e65090",
        "checked": "2026-10-23",
        "checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
      }
    ]
  },
  "metadata": {
    "specs": {
      "Manufacturer": "WCH(Jiangsu Qin Heng)",
      "Package": "LQFP-44(10x10)",
      "Category": "Interface ICs",
      "Pins": "44"
    },
    "characteristics": {
      "version": 1,
      "source": "datasheet",
      "datasheet_sha256": "99b5378163fd173a939fa8bf5d90c32a70f4675f1bc177f4be90ba2f92794516",
      "rows": [
        {
          "name": "Supply voltage",
          "symbol": "VCC",
          "kind": "electrical",
          "unit": "V",
          "min": 3.3,
          "typ": 5,
          "max": 5.3,
          "conditions": "TA=25℃, VCC=5V",
          "source_page": 12,
          "source": "datasheet"
        },
        {
          "name": "Supply current during working at 5V",
          "symbol": "ICC",
          "kind": "electrical",
          "unit": "mA",
          "min": 2,
          "typ": 10,
          "max": 40,
          "conditions": "TA=25℃, VCC=5V",
          "source_page": 12,
          "source": "datasheet"
        },
        {
          "name": "Supply current during working at 3.3V",
          "symbol": "ICC3",
          "kind": "electrical",
          "unit": "mA",
          "min": 0.5,
          "typ": 5,
          "max": 20,
          "conditions": "",
          "source_page": 12,
          "source": "datasheet"
        },
        {
          "name": "Supply current at 3.3V during low-power sleep",
          "symbol": "ISLP3",
          "kind": "electrical",
          "unit": "uA",
          "min": 5,
          "typ": 50,
          "max": 500,
          "conditions": "",
          "source_page": 12,
          "source": "datasheet"
        },
        {
          "name": "Low level input voltage",
          "symbol": "VIL",
          "kind": "electrical",
          "unit": "V",
          "min": -0.5,
          "typ": null,
          "max": 0.8,
          "conditions": "",
          "source_page": 12,
          "source": "datasheet"
        },
        {
          "name": "High level input voltage",
          "symbol": "VIH",
          "kind": "electrical",
          "unit": "V",
          "min": 2,
          "typ": null,
          "max": null,
          "conditions": "max printed as VCC+0.5",
          "source_page": 12,
          "source": "datasheet"
        },
        {
          "name": "Low level output voltage",
          "symbol": "VOL",
          "kind": "electrical",
          "unit": "V",
          "min": null,
          "typ": null,
          "max": 0.5,
          "conditions": "4mA draw current",
          "source_page": 12,
          "source": "datasheet"
        },
        {
          "name": "Input current of input with built-in pull-down resistor",
          "symbol": "IIN",
          "kind": "electrical",
          "unit": "uA",
          "min": null,
          "typ": null,
          "max": 10,
          "conditions": "",
          "source_page": 12,
          "source": "datasheet"
        },
        {
          "name": "Input current at input with weak pull-up resistor",
          "symbol": "IUP1",
          "kind": "electrical",
          "unit": "uA",
          "min": 2,
          "typ": 5,
          "max": 170,
          "conditions": "",
          "source_page": 12,
          "source": "datasheet"
        },
        {
          "name": "Input current of input with built-in weak pull-down resistor",
          "symbol": "IDN1",
          "kind": "electrical",
          "unit": "uA",
          "min": -20,
          "typ": 40,
          "max": 80,
          "conditions": "",
          "source_page": 12,
          "source": "datasheet"
        },
        {
          "name": "Ambient temperature during operation (VCC=5V)",
          "symbol": "TA",
          "kind": "absolute_maximum",
          "unit": "℃",
          "min": -40,
          "typ": null,
          "max": 85,
          "conditions": "VCC=5V",
          "source_page": 12,
          "source": "datasheet"
        },
        {
          "name": "Ambient temperature during operation (VCC=3.3V)",
          "symbol": "TA",
          "kind": "absolute_maximum",
          "unit": "℃",
          "min": -40,
          "typ": null,
          "max": 65,
          "conditions": "VCC=3.3V",
          "source_page": 12,
          "source": "datasheet"
        },
        {
          "name": "Ambient temperature during storage",
          "symbol": "TS",
          "kind": "absolute_maximum",
          "unit": "℃",
          "min": -55,
          "typ": null,
          "max": 125,
          "conditions": "",
          "source_page": 12,
          "source": "datasheet"
        },
        {
          "name": "Supply voltage",
          "symbol": "VCC",
          "kind": "absolute_maximum",
          "unit": "V",
          "min": -0.5,
          "typ": null,
          "max": 6,
          "conditions": "",
          "source_page": 12,
          "source": "datasheet"
        },
        {
          "name": "Voltage on the input or output pins",
          "symbol": "VIO",
          "kind": "absolute_maximum",
          "unit": "V",
          "min": -0.5,
          "typ": null,
          "max": null,
          "conditions": "max printed as VCC+0.5",
          "source_page": 12,
          "source": "datasheet"
        },
        {
          "name": "XI input frequency, crystal frequency",
          "symbol": "FXI",
          "kind": "timing",
          "unit": "MHz",
          "min": 0.9216,
          "typ": 22.1184,
          "max": 32,
          "conditions": "max 24 at VCC=3.3V",
          "source_page": 13,
          "source": "datasheet"
        },
        {
          "name": "Time from clear interrupt operation to cancelling interrupt",
          "symbol": "TIC",
          "kind": "timing",
          "unit": "nS",
          "min": 2,
          "typ": 20,
          "max": 100,
          "conditions": "",
          "source_page": 13,
          "source": "datasheet"
        },
        {
          "name": "Width of effective strobe writing pulse WR",
          "symbol": "TWW",
          "kind": "timing",
          "unit": "nS",
          "min": 60,
          "typ": null,
          "max": null,
          "conditions": "VCC=5V",
          "source_page": 13,
          "source": "datasheet"
        },
        {
          "name": "Width of effective strobe reading pulse RD",
          "symbol": "TRW",
          "kind": "timing",
          "unit": "nS",
          "min": 50,
          "typ": null,
          "max": null,
          "conditions": "VCC=5V",
          "source_page": 13,
          "source": "datasheet"
        },
        {
          "name": "Interval width of strobe reading or writing pulse",
          "symbol": "TWS",
          "kind": "timing",
          "unit": "nS",
          "min": 40,
          "typ": null,
          "max": null,
          "conditions": "VCC=5V",
          "source_page": 13,
          "source": "datasheet"
        },
        {
          "name": "Address input setup time before RD or WR",
          "symbol": "TAS",
          "kind": "timing",
          "unit": "nS",
          "min": 5,
          "typ": null,
          "max": null,
          "conditions": "VCC=5V",
          "source_page": 13,
          "source": "datasheet"
        },
        {
          "name": "Address input maintaining time after RD or WR",
          "symbol": "TAH",
          "kind": "timing",
          "unit": "nS",
          "min": 3,
          "typ": null,
          "max": null,
          "conditions": "",
          "source_page": 13,
          "source": "datasheet"
        },
        {
          "name": "Data input setup time before write strobe WR",
          "symbol": "TIS",
          "kind": "timing",
          "unit": "nS",
          "min": 0,
          "typ": null,
          "max": null,
          "conditions": "",
          "source_page": 13,
          "source": "datasheet"
        },
        {
          "name": "Data input maintaining time after strobe writing WR",
          "symbol": "TIH",
          "kind": "timing",
          "unit": "nS",
          "min": 10,
          "typ": null,
          "max": null,
          "conditions": "",
          "source_page": 13,
          "source": "datasheet"
        },
        {
          "name": "Data input hold time on write strobe WR front edge",
          "symbol": "TIHX",
          "kind": "timing",
          "unit": "nS",
          "min": 80,
          "typ": null,
          "max": null,
          "conditions": "",
          "source_page": 13,
          "source": "datasheet"
        },
        {
          "name": "Effective strobe reading RD to effective data output",
          "symbol": "TON",
          "kind": "timing",
          "unit": "nS",
          "min": 15,
          "typ": null,
          "max": 25,
          "conditions": "VCC=5V",
          "source_page": 13,
          "source": "datasheet"
        },
        {
          "name": "Ineffective strobe reading RD to ineffective data output",
          "symbol": "TOF",
          "kind": "timing",
          "unit": "nS",
          "min": null,
          "typ": null,
          "max": 20,
          "conditions": "VCC=5V",
          "source_page": 13,
          "source": "datasheet"
        },
        {
          "name": "Width of effective address latch pulse ALE",
          "symbol": "TLW",
          "kind": "timing",
          "unit": "nS",
          "min": 6,
          "typ": null,
          "max": null,
          "conditions": "VCC=5V",
          "source_page": 13,
          "source": "datasheet"
        },
        {
          "name": "Address input setup time before address latch ALE",
          "symbol": "TLS",
          "kind": "timing",
          "unit": "nS",
          "min": 5,
          "typ": null,
          "max": null,
          "conditions": "VCC=5V",
          "source_page": 13,
          "source": "datasheet"
        },
        {
          "name": "Address input hold time after address latch ALE",
          "symbol": "TLH",
          "kind": "timing",
          "unit": "nS",
          "min": 3,
          "typ": null,
          "max": null,
          "conditions": "",
          "source_page": 13,
          "source": "datasheet"
        },
        {
          "name": "Multiplexed address output invalid until read strobe RD valid",
          "symbol": "TLZ",
          "kind": "timing",
          "unit": "nS",
          "min": 0,
          "typ": null,
          "max": null,
          "conditions": "",
          "source_page": 13,
          "source": "datasheet"
        }
      ]
    }
  },
  "variants": [],
  "sections": [
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    "info"
  ],
  "discovery_triggers": [
    "ch438q"
  ],
  "discovery_pitch": "CH438Q (WCH(Jiangsu Qin Heng)) component page: datasheet pinout, KiCad symbol, footprint and 3D.",
  "author": {
    "name": "Ray",
    "email": "[email protected]"
  },
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  "visibility": {
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}