# Fashion Star RA8-U25H-M Bus Servo

> Fashion Star RA8-U25H-M is a dual-shaft 12 V UART bus servo: cored motor, 273:1 all-metal gears, 2.45 N·m (25 kg·cm) stall and 0.44 N·m rated torque, 51 rpm no-load, 12-bit magnetic encoder, UART/TTL up to 1 Mbps with IDs 0–254, 9.0–12.6 V, 63 g, 40 × 40 × 20 mm.

- Manufacturer: Fashion Star
- Part number: RA8-U25H-M
- Category: Actuators
- Canonical page: https://www.xirkit.io/products/fashion-star-ra8-u25h-m-bus-servo-4cc0
- Pinout: https://www.xirkit.io/products/fashion-star-ra8-u25h-m-bus-servo-4cc0/pinout
- Structured JSON: https://www.xirkit.io/products/fashion-star-ra8-u25h-m-bus-servo-4cc0/data.json
- Source: Xirkit structured parts catalog — every value traced to a cited document; unknowns are explicit.

## Key specifications

| Property | Value |
| --- | --- |
| Actuator type | smart_servo |
| Gearbox | 273:1 |
| Rated torque | 0.44 N·m |
| Peak torque | 2.45 N·m |
| Rated speed | 18 rpm |
| No-load speed | 51 rpm |
| Rated voltage | 12.6 V |
| Encoder | 12-bit magnetic absolute (2,048 steps per 360°, 0.176°) |
| Control interface | UART |
| Control modes | single-turn angle, multi-turn angle, damping |
| Dimensions | 40 × 20 × 40 mm |
| Operating temperature | -10 to 60 °C |

## Pinout (3 pins, 0 with electrical limits)

| Pin | Position | Kind | Chip pad | Functions | VIH | VIL | VOH | VOL | IOH | IOL | 5 V tolerant |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| GND | PH2.0-3Pin · 1 | ground | — | ground | — | — | — | — | — | — | — |
| VDD | PH2.0-3Pin · 2 | power in | — | power_in | — | — | — | — | — | — | — |
| Signal | PH2.0-3Pin · 3 | signal | — | signal | — | — | — | — | — | — | — |

## Where to buy

| Supplier | Price | Stock | Checked | URL |
| --- | --- | --- | --- | --- |
| aifitlab.com | 35 USD | in_stock | 2026-10-20 | https://aifitlab.com/products/fashion-star-ha8-u25-m-uart-bus-servo?variant=44758318678152 |

## FAQ

**How much does the Fashion Star RA8-U25H-M Bus Servo cost?**

From $35 at aifitlab.com. Prices are observed unit prices before tax and shipping.

**What are the Fashion Star RA8-U25H-M Bus Servo dimensions?**

40 × 20 × 40 mm. A STEP model is available for enclosure fit checks.

**Where does this Fashion Star RA8-U25H-M Bus Servo data come from?**

Every value in this record is traced to a source — 2 documents including the board and chip datasheets — with the page and table cited per value. Unknowns are left explicit, never guessed.

## Sources

- [Fashion Star RA8-U25H-M Bus Servo datasheet](https://aifitlab.com/products/fashion-star-ha8-u25-m-uart-bus-servo)
- [aifitlab.com listing](https://aifitlab.com/products/fashion-star-ha8-u25-m-uart-bus-servo?variant=44758318678152)

## Part graph

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