# CDC421A250RGER

**Texas Instruments** · Clock Generators, PLLs, Frequency Synthesizers · VQFN-24-EP(4x4)

CDC421A250RGER from Texas Instruments, in a VQFN-24-EP(4x4). 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 | CE | input | Chip enable LVCMOS input: CE = 1 enables the device and outputs; CE = 0 disables all current sources so LVPECL outputs are Hi-Z. |
| 2 | NC | unconnected | TI test pin; do not connect, leave floating. |
| 3 | NC | unconnected | TI test pin; do not connect, leave floating. |
| 4 | NC | unconnected | TI test pin; do not connect, leave floating. |
| 5 | NC | unconnected | TI test pin; do not connect, leave floating. |
| 6 | NC | unconnected | TI test pin; do not connect, leave floating. |
| 7 | OUTN | output | High-speed negative differential LVPECL output, enabled by the CE pin. |
| 8 | GND | power_in | Ground. |
| 9 | GND | power_in | Ground. |
| 10 | OUTP | output | High-speed positive differential LVPECL output, enabled by the CE pin. |
| 11 | NC | unconnected | TI test pin; do not connect, leave floating. |
| 12 | NC | unconnected | TI test pin; do not connect, leave floating. |
| 13 | NC | unconnected | TI test pin; do not connect, leave floating. |
| 14 | NC | unconnected | TI test pin; do not connect, leave floating. |
| 15 | NC | unconnected | TI test pin; do not connect, leave floating. |
| 16 | VCC | power_in | 3.3-V power supply; recommended operating range 3.0 V to 3.6 V. |
| 17 | VCC | power_in | 3.3-V power supply; recommended operating range 3.0 V to 3.6 V. |
| 18 | NC | unconnected | TI test pin; do not connect, leave floating. |
| 19 | NC | unconnected | TI test pin; do not connect, leave floating. |
| 20 | NC | unconnected | TI test pin; do not connect, leave floating. |
| 21 | XIN1 | input | In crystal mode, connect to one end of the crystal (XIN2 to the other end); in LVCMOS single-ended driven mode, this pin is the input reference. |
| 22 | XIN2 | input | In crystal mode, connect to the other end of the crystal; in LVCMOS single-ended driven mode, connect to GND. |
| 23 | NC | unconnected | TI test pin; do not connect, leave floating. |
| 24 | NC | unconnected | TI test pin; do not connect, leave floating. |
| 25 | Thermal pad | passive | Exposed thermal pad on the package bottom; must be soldered to the PCB for thermal and mechanical performance. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | VQFN-24-EP(4x4) |
| Category | Clock/Timing |
| Pins | 25 |

## CAD (KiCad official)

- Symbol: `CDC421A250RGER`
- Footprint: `Package_DFN_QFN:QFN-24-1EP_4x4mm_P0.5mm_EP2.7x2.7mm`
- 3D model: VQFN-24-EP(4x4) (KiCad packages3D, STEP)
- 3D model files: `cdc421a250rger-etched.step` / `cdc421a250rger-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `cdc421a250rger.step` / `cdc421a250rger.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/cdc421a100) (17 pp, sha256 `915ca5742046cc8c`, retrieved 2026-10-08, tier: lcsc)
- **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/cdc421a250rger-datasheet.pdf)