component
sit491eesd
Public Unreviewedby Ray
SIT RS-485 / RS-422 ICs, SOP-14. Datasheet-verified pinout, KiCad symbol/footprint/3D.
3D Model
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markdownSIT491EESD
SIT · RS-485 / RS-422 ICs · SOP-14
SIT491EESD from SIT, in a SOP-14. 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 | NC | unconnected | No Connection. Not internally connected. |
| 2 | RO | output | Receiver Output. When /RE is low, if A-B ≥ -10mV, RO is high; if A-B ≤ -200mV, RO is low. High-impedance when /RE is high. |
| 3 | /RE | input | Receiver Output Enable (active-low). RO is enabled when /RE is low; RO is high impedance when /RE is high. If /RE is high and DE is low, the device enters low-power shutdown. |
| 4 | DE | input | Driver Output Enable. Driver outputs are enabled when DE is high; high-impedance when DE is low. If /RE is high and DE is low, the device enters low-power shutdown. |
| 5 | DI | input | Driver Input. When DE is high, a low on DI forces output A/Y low and B/Z high; a high on DI forces A/Y high and B/Z low. VIH ≥ 2.0V, VIL ≤ 0.8V. |
| 6 | GND | power_in | Ground reference for all voltages. |
| 7 | GND | power_in | Ground reference for all voltages. |
| 8 | NC | unconnected | No Connection. Not internally connected. |
| 9 | Y | output | Non-inverting Driver Output (RS-485/RS-422 differential output). Differential driver output typically 2.3V into RL=27Ω. ±15kV HBM ESD protected. |
| 10 | Z | output | Inverting Driver Output (RS-485/RS-422 differential output). Complement of Y. ±15kV HBM ESD protected. |
| 11 | B | input | Inverting Receiver Input (RS-485/RS-422). Receiver input resistance ≥96kΩ (1/8 unit load). Common-mode range -7V to +12V. ±15kV HBM ESD protected. |
| 12 | A | input | Non-inverting Receiver Input (RS-485/RS-422). Receiver input resistance ≥96kΩ (1/8 unit load). Common-mode range -7V to +12V. ±15kV HBM ESD protected. |
| 13 | VCC | power_in | Positive Supply or No Connection. Datasheet notes this pin may be tied to VCC (4.5V-5.5V) or left unconnected; typically bonded together with pin 14. |
| 14 | VCC | power_in | Positive Supply. Operating range 4.5V to 5.5V; absolute maximum +7V. Decouple to GND with a bypass capacitor. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | SIT |
| Package | SOP-14 |
| Category | Interface |
| Pins | 14 |
Ordering variants
SIT491EESDSIT491EESDEPD
CAD (KiCad official)
- Symbol:
SIT491EESD - Footprint:
Package_SO:SOIC-14_3.9x8.7mm_P1.27mm - 3D model: SOP-14 (KiCad packages3D, STEP)
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: SIT datasheet (None pp, sha256
49b7124e34a09d2c, retrieved 2026-08-17, tier: lcsc) - 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).