component
TD521D485H-A
Public Made by Adomby adom
VISOM RS485 Bus Modules, DIP-8. 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
markdownTD521D485H-A
VISOM · RS485 Bus Modules · DIP-8
TD521D485H-A from VISOM, in a DIP-8. 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 | VCC | power_in | Positive supply input on the logic side. Nominal 5 V (4.75-5.25 V) for TD521D485H-A; absolute max 7 V, min -0.7 V. Typical quiescent current 30 mA, max operating current 90 mA. No reverse-polarity protection. |
| 2 | GND | power_in | Logic-side (input) ground reference for VCC, TXD, and RXD. Isolated from the RS-485 side (RGND) by 2500 VDC. |
| 3 | TXD | input | UART transmit data input from host MCU (5 V logic for TD521D485H-A). VIH >= 0.7VCC, VIL <= 0.3VCC. Internal 10 kΩ pull-up to VCC; TXD drive current 2 mA. Data driven onto the RS-485 A/B bus with automatic direction control. |
| 4 | RXD | output | UART receive data output to host MCU. Push-pull, IRXD up to 10 mA; VOH >= VCC-0.4 V @ 4 mA, VOL <= 0.4 V @ 4 mA. High when VA-VB >= +200 mV, low when VA-VB <= -200 mV; indeterminate in the +/-200 mV window. |
| 7 | VO | power_out | Isolated positive output of the on-board 2500 VDC isolated DC-DC (bus-side supply). Nominal value matches the internal bus-side rail used by the RS-485 driver; leave floating (open) if unused. |
| 8 | B | bidirectional | RS-485 differential bus line B (inverting). Referenced to RGND on the isolated side. Internal pull-down and 47 kΩ bias resistor; receiver input impedance >= 48 kΩ over -7 V <= VCM <= +12 V. Integrated ESD protection. |
| 9 | A | bidirectional | RS-485 differential bus line A (non-inverting). Referenced to RGND on the isolated side. Differential output |
| 10 | RGND | power_out | Isolated bus-side ground (return for VO and reference for A/B). Galvanically isolated from GND (pin 2) by 2500 VDC. Leave floating if VO is not used; can connect to inner cable shield in double-shielded installations. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | VISOM |
| Package | DIP-8 |
| Category | IoT/Communication Modules |
| Pins | 8 |
Ordering variants
Same part, different packaging or reel option.
TD521D485H-ATD521D485H-ATD321D485H-A
CAD (KiCad official)
- Symbol:
TD521D485H-A - Footprint:
Package_DIP:DIP-8_W7.62mm - 3D model: DIP-8 (KiCad packages3D, STEP)
- 3D model files:
td521d485h-a-etched.step/td521d485h-a-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);td521d485h-a.step/td521d485h-a.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: VISOM datasheet (5 pp, sha256
c27581d3a59f8a52, 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).