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Contents

README

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DS89C21TMX

Texas Instruments · RS-485 / RS-422 ICs · SOIC-8

DS89C21TMX from Texas Instruments, in a SOIC-8. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 VCC power_in Supply voltage pin; recommended operating range 4.50V to 5.50V, absolute maximum 7V.
2 RO output Receiver TTL/CMOS-compatible output; drives HIGH (VOH 3.8-4.9V typ, IOH=-6mA) when RI-RI* differential input is ≥+200mV or open, and LOW (VOL ≤0.3V, IOL=6mA) when differential input is ≤-200mV.
3 DI input Driver TTL/CMOS-compatible input; VIH 2.0V to VCC, VIL GND to 0.8V; HIGH level drives DO high and DO* low.
4 GND power_in Ground reference pin for the device.
5 DO* output Inverting (complementary) differential driver output; differential output voltage 2.0-3.0V into a 100Ω load, complementary to DO.
6 DO output Non-inverting differential driver output; unloaded output voltage 4.2-6.0V, differential output voltage 2.0-3.0V into a 100Ω load, follows DI input state.
7 RI* input Inverting differential receiver input; differential threshold ±200mV, absolute maximum input voltage ±14V, input impedance 5.0-9.5kΩ.
8 RI input Non-inverting differential receiver input; differential threshold ±200mV (failsafe HIGH output when open/non-terminated), absolute maximum input voltage ±14V, input impedance 5.0-9.5kΩ.

Key specifications

Parameter Value
Manufacturer Texas Instruments
Package SOIC-8
Category Interface
Pins 8

CAD (KiCad official)

  • Symbol: DS89C21TMX
  • Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
  • 3D model: SOIC-8 (KiCad packages3D, STEP)
  • 3D model files: ds89c21tmx-etched.step / ds89c21tmx-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); ds89c21tmx.step / ds89c21tmx.glb are the bare package body.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Texas Instruments datasheet (16 pp, sha256 b726d09ebb2243f6, retrieved 2026-09-24, tier: lcsc)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.2, primary claude-sonnet-5 (text+vision), consensus claude-opus-4-8 (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF