component
LTC2870IUFD#TRPBF
Public Made by Adomby adom
Analog Devices RS-485 / RS-422 ICs, QFN-28(4x5). Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
main
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{
"slug": "ltc2870iufd-trpbf",
"version": "0.1.0",
"type": "component",
"description": "Analog Devices RS-485 / RS-422 ICs, QFN-28(4x5). Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.",
"tags": [
"component",
"interface",
"ltc2870iufd#trpbf",
"factory-2.0.0",
"extractor-text"
],
"dependencies": {},
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"component": {
"mpn": "LTC2870IUFD#TRPBF",
"manufacturer": "Analog Devices",
"package": "QFN-28(4x5)",
"pin_count": 29,
"category": "Interface",
"subcategory": "RS-485 / RS-422 ICs",
"datasheet": "https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8590145891929141248",
"parts": {
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"model_3d_step_plain": "ltc2870iufd-trpbf.step",
"lbr": "ltc2870iufd-trpbf.lbr"
},
"distributor_links": {
"lcsc": "C580626",
"digikey": "LTC2870IUFD#TRPBFTR-ND",
"mouser": "584-LTC2870IUFDTRPBF"
},
"distributor_check": {
"checked_at": "2026-10-21T00:55:25Z",
"source": "Component Ocean /api/assign-pns",
"digikey": {
"pn": "LTC2870IUFD#TRPBFTR-ND",
"status": "found",
"lifecycle": "Active"
},
"mouser": {
"pn": "584-LTC2870IUFDTRPBF",
"status": "found",
"lifecycle": "Restricted Availability"
}
},
"pins": [
{
"number": "1",
"name": "VEE",
"type": "power_out",
"description": "Generated negative supply (-6.3V) for the RS232 driver; tie all VEE pins together and connect a 1µF capacitor between VEE (sequentially after CAP) and GND."
},
{
"number": "2",
"name": "RA",
"type": "output",
"description": "RS485 differential receiver output or RS232 receiver output 1, held Hi-Z when RXEN is high."
},
{
"number": "3",
"name": "RB",
"type": "output",
"description": "RS232 receiver output 2, held Hi-Z when RXEN is high."
},
{
"number": "4",
"name": "485/232",
"type": "input",
"description": "Interface select: logic low enables RS232 mode and logic high enables RS485 mode; do not float."
},
{
"number": "5",
"name": "RXEN",
"type": "input",
"description": "Receiver enable: logic high disables the RS232 and RS485 receivers leaving outputs Hi-Z, logic low enables them; do not float."
},
{
"number": "6",
"name": "DXEN",
"type": "input",
"description": "Driver enable: logic low disables the RS232 and RS485 drivers leaving outputs Hi-Z, logic high enables them; do not float."
},
{
"number": "7",
"name": "DY",
"type": "input",
"description": "RS485 driver input or RS232 driver input 1; do not float."
},
{
"number": "8",
"name": "DZ",
"type": "input",
"description": "RS232 driver input 2; do not float."
},
{
"number": "9",
"name": "FEN",
"type": "input",
"description": "Fast enable: logic high keeps the integrated DC/DC converter active regardless of driver, receiver and termination enables; logic low disables fast enable mode; do not float."
},
{
"number": "10",
"name": "GND",
"type": "power_in",
"description": "Ground; tie all four GND pins together."
},
{
"number": "11",
"name": "CAP",
"type": "passive",
"description": "Charge pump capacitor for the generated negative supply; connect a 220nF capacitor between CAP and SW."
},
{
"number": "12",
"name": "VEE",
"type": "power_out",
"description": "Generated negative supply (-6.3V) for the RS232 driver; tie together with the other VEE pins and a 1µF capacitor to GND."
},
{
"number": "13",
"name": "GND",
"type": "power_in",
"description": "Ground; tie all four GND pins together."
},
{
"number": "14",
"name": "SW",
"type": "passive",
"description": "Switch pin for the boost converter; connect a 10µH inductor between SW and VCC."
},
{
"number": "15",
"name": "VDD",
"type": "power_out",
"description": "Generated positive supply (+7V) for the RS232 driver; connect a 1µF capacitor between VDD and GND."
},
{
"number": "16",
"name": "VCC",
"type": "power_in",
"description": "Input supply, 3V to 5.5V; tie all three VCC pins together and connect a 2.2µF or larger capacitor between VCC (adjacent to VDD) and GND."
},
{
"number": "17",
"name": "Z",
"type": "bidirectional",
"description": "RS485 negative driver output or RS232 driver output 2 (LTC2870); also the RS485 negative receiver input in half-duplex mode."
},
{
"number": "18",
"name": "GND",
"type": "power_in",
"description": "Ground; tie all four GND pins together."
},
{
"number": "19",
"name": "Y",
"type": "bidirectional",
"description": "RS485 positive driver output or RS232 driver output 1 (LTC2870); also the RS485 positive receiver input in half-duplex mode."
},
{
"number": "20",
"name": "VCC",
"type": "power_in",
"description": "Input supply, 3V to 5.5V; tie together with the other VCC pins and the 2.2µF or larger VCC-to-GND capacitor."
},
{
"number": "21",
"name": "B",
"type": "input",
"description": "RS485 negative receiver input in full-duplex mode, or RS232 receiver input 2 (LTC2870)."
},
{
"number": "22",
"name": "A",
"type": "input",
"description": "RS485 positive receiver input in full-duplex mode, or RS232 receiver input 1 (LTC2870)."
},
{
"number": "23",
"name": "GND",
"type": "power_in",
"description": "Ground; tie all four GND pins together."
},
{
"number": "24",
"name": "VCC",
"type": "power_in",
"description": "Input supply, 3V to 5.5V; tie together with the other VCC pins and the 2.2µF or larger VCC-to-GND capacitor."
},
{
"number": "25",
"name": "VL",
"type": "power_in",
"description": "Logic supply, 1.7V to 5.5V, for receiver outputs, driver inputs and control inputs; keep VL ≤ VCC for proper operation."
},
{
"number": "26",
"name": "LB",
"type": "input",
"description": "Loopback enable: logic high routes driver input logic levels to the receiver outputs; do not float."
},
{
"number": "27",
"name": "H/F",
"type": "input",
"description": "RS485 half-duplex select: logic low selects full-duplex and logic high selects half-duplex operation; do not float."
},
{
"number": "28",
"name": "TE485",
"type": "input",
"description": "RS485 termination enable: logic high enables 120Ω resistors between A-B and Y-Z; logic low leaves them open; do not float."
},
{
"number": "29",
"name": "VEE",
"type": "power_out",
"description": "Exposed pad, electrically VEE (generated negative supply); must be soldered to the PCB."
}
],
"provenance": {
"extractor": "extract_pins 0.3",
"factory_chain": {
"factory": "2.0.0",
"extractor": "extract_pins 0.3",
"primary_model": "claude-haiku-5-5",
"primary_mode": "text",
"consensus_model": "claude-sonnet-5-5",
"consensus": "agreed",
"guards": "pin_guards 0.1: passed",
"guard_notes": [
"extractor flagged: The package-variant pin mapping was taken from the LTC2870 QFN column of the Pin Functions table (pa; Pins RO, ROUT1, ROUT2, RIN1, RIN2, DIN1, DIN2, DI, DX232, RX232, DX485, RX485, CH2, DOUT1 and DOUT2 ; Pin 29 is the exposed thermal pad and is connected to VEE per the datasheet. It is listed here as a "
],
"pages_sent": 8,
"cost_usd": 0.0778,
"at": "2026-10-21T00:51:48"
},
"datasheet": {
"url": "https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8590145891929141248",
"pages": 42,
"sha256": "bed34b4f97b6f3f8",
"source_tier": "lcsc"
},
"cad": "KiCad official (CC-BY-SA 4.0)",
"pins": {
"total": 29,
"described": 29,
"cites_pages": true,
"refuses_to_fabricate": true
}
},
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"zmin_mm": 0.0,
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"footprint_binding": "identity",
"sha256": "028686d522379f70cdcac54d7cbc05f7e8d72fe41515288068d2e2da8d27bc8d",
"checked": "2026-10-21",
"checked_by": "factory/step_pose.py (Z-up, origin, seat, binding)"
},
{
"file": "ltc2870iufd-trpbf-etched.step",
"role": "eda",
"up": "Z",
"units": "mm",
"origin": "footprint origin = pad-pattern centre",
"seat": "z = 0",
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"sha256": "0c0f97952184e2b4cd6aec0f1023a908e641d780e2067c7422904b075d2ae994",
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}
}