# UCC21521CDWR

**Texas Instruments** · Isolators - Gate Drivers · SOIC-16-300mil

UCC21521CDWR from Texas Instruments, in a SOIC-16-300mil. 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 | INA | input | Input signal for the A channel with a TTL/CMOS compatible threshold; the pin is pulled low internally if left open and should be tied to ground if unused. |
| 2 | INB | input | Input signal for the B channel with a TTL/CMOS compatible threshold; the pin is pulled low internally if left open and should be tied to ground if unused. |
| 3 | VCCI | power_in | Primary-side supply voltage (3 V to 18 V recommended range), locally decoupled to GND with a low ESR/ESL capacitor placed as close to the device as possible. |
| 4 | GND | power_in | Primary-side ground reference; all primary-side signals are referenced to this pin. |
| 5 | EN | input | Enables both driver outputs when high or left open (internally pulled high) and disables the outputs when low; tying it to VCCI is recommended for better noise immunity when unused. |
| 6 | DT | input | Programmable dead-time pin: tying it to VCCI allows overlap, while a 500 Ω to 500 kΩ resistor to GND sets dead time as DT (ns) = 10 × RDT (kΩ), with a ceramic capacitor of 2.2 nF or above recommended in parallel; leaving it floating is not recommended. |
| 7 | NC | unconnected | No internal connection. |
| 8 | VCCI | power_in | Primary-side supply voltage, internally shorted to pin 3 (VCCI), so it should be connected and decoupled alongside pin 3. |
| 9 | VSSB | power_in | Ground for the secondary-side driver B and its ground reference for the B channel. |
| 10 | OUTB | output | Output of driver B; connect to the gate of the B-channel FET or IGBT. |
| 11 | VDDB | power_in | Secondary-side power for driver B, to be locally decoupled to VSSB with a low ESR/ESL capacitor placed as close to the device as possible. |
| 12 | NC | unconnected | No internal connection. |
| 13 | NC | unconnected | No internal connection. |
| 14 | VSSA | power_in | Ground for secondary-side driver A and its ground reference for the A channel. |
| 15 | OUTA | output | Output of driver A; connect to the gate of the A-channel FET or IGBT. |
| 16 | VDDA | power_in | Secondary-side power for driver A, to be locally decoupled to VSSA with a low ESR/ESL capacitor placed as close to the device as possible. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | SOIC-16-300mil |
| Category | Power Management (PMIC) |
| Pins | 16 |

## CAD (KiCad official)

- Symbol: `UCC21521CDWR`
- Footprint: `Package_SO:SOIC-16_3.9x9.9mm_P1.27mm`
- 3D model: SOIC-16-300mil (KiCad packages3D, STEP)
- 3D model files: `ucc21521cdwr-etched.step` / `ucc21521cdwr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `ucc21521cdwr.step` / `ucc21521cdwr.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Texas Instruments datasheet](https://www.ti.com/cn/lit/gpn/ucc21521) (50 pp, sha256 `93b1d040e8ae41ee`, retrieved 2026-10-07, 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:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-5-5` (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/ucc21521cdwr-datasheet.pdf)