# ISOW7721DFMR

**Texas Instruments** · Digital Isolators (With Power) · SOIC-20

ISOW7721DFMR from Texas Instruments, in a SOIC-20. 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 | VIO | power_in | Side 1 logic supply voltage. |
| 2 | INA | input | Input channel A. |
| 3 | OUTB | output | Output channel B. |
| 4 | EN_IO1 | input | Output Enable 1; when high or open the channel output pin on side 1 is enabled, when low the output is in high impedance state and transmitter is disabled. |
| 5 | EN | bidirectional | Power converter enable input pin; DC-DC power converter is enabled when high to VIO voltage level and disabled when low at GND1 voltage level. |
| 6 | GNDIO | power_in | Ground connection for VIO; GND1 and GNDIO need to be shorted on board. |
| 7 | LF | input | Multiple device primary/secondary control logic; connect to GND1 when used as primary device or to VDD if used as secondary device. |
| 8 | CC | bidirectional | Multiple device primary/secondary synchronization pin; when LF is set to GND1 CC is an output, when LF is set to VDD CC is an input. |
| 9 | VDD | power_in | Side 1 DC-DC converter power supply voltage. |
| 10 | GND1 | power_in | Ground connection for VDD; GND1 and GNDIO need to be shorted on board. |
| 11 | GND2 | power_in | Ground connection for VISOOUT; GND2 and GISOIN pins can be shorted on board or connected through a ferrite bead. |
| 12 | VISOOUT | power_out | Isolated power converter output voltage; VISOIN and VISOOUT pins can be shorted on board or connected through a ferrite bead. |
| 13 | VSEL | input | VISOOUT selection pin; VISOOUT = 5 V when VSEL shorted to VISOOUT, VISOOUT = 3.3 V when VSEL shorted to GND2. |
| 14 | NC | unconnected | No Connect. |
| 15 | GISOIN | power_in | Ground connection for VISOIN; GND2 and GISOIN pins can be shorted on board or connected through a ferrite bead. |
| 16 | NC | unconnected | No Connect. |
| 17 | EN_IO2 | input | Output Enable 2; when high or open the channel output pin on side 2 is enabled, when low the output is in high impedance state and transmitter is disabled. |
| 18 | INB | input | Input channel B. |
| 19 | OUTA | output | Output channel A. |
| 20 | VISOIN | power_in | Side 2 supply voltage for isolation channels; VISOIN and VISOOUT pins can be shorted on board or connected through a ferrite bead. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | SOIC-20 |
| Category | Signal Isolation Devices |
| Pins | 20 |

## CAD (KiCad official)

- Symbol: `ISOW7721DFMR`
- Footprint: `Package_SO:SOIC-20W_7.5x12.8mm_P1.27mm`
- 3D model: SOIC-20 (KiCad packages3D, STEP)
- 3D model files: `isow7721dfmr-etched.step` / `isow7721dfmr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `isow7721dfmr.step` / `isow7721dfmr.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Texas Instruments datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8597547427327467520) (56 pp, sha256 `23d359783521eebd`, retrieved 2026-10-05, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-4-5-20251001` (text), consensus `claude-sonnet-5-5` (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](docs/isow7721dfmr-datasheet.pdf)