FUSB251UCX - USB Type-C CC/SBU Protection Switch | onsemi
MPN: FUSB251UCX ✓ Hoạt độngFUSB251UCX Tóm tắt
A Type-C CC and SBU protection IC is a category of USB interface companion device that sits between the Type-C connector and the system PD controller, providing isolation, over-voltage protection, and signal routing on the Configuration Channel and Sideband Use lines. Within the broader power management and interface IC taxonomy, it belongs to USB Type-C interface protection switches, which in turn are a sub-category of interface ICs. These devices are mandatory building blocks in modern USB-C designs that need robust protection for hot-plug events and voltage faults.
Key features of the FUSB251UCX include 4-channel SPST switching, programmable over-voltage protection thresholds via I2C, dead-battery Rd pull-down support that allows a source to provide VBUS when the device is unpowered, over-current protection, and thermal shutdown. The OVP response time is designed to clamp faults before downstream damage occurs, and the device supports CC signaling for USB Type-C attach/detach and orientation detection. The I2C interface enables host software to read status, configure thresholds, and switch channels on demand.
Architecturally, the FUSB251UCX uses integrated N-MOSFET switches with OVP clamping structures. When VDD is valid, internal gate drivers turn on the switches; when a fault voltage exceeds the programmed threshold on any protected line, the switch opens in microseconds, disconnecting the protected PD controller from the fault. The dead-battery Rd pull-down is hard-wired (non-I2C controlled) so a power source can detect an attached sink even when the sink's battery is fully depleted.
Typical applications include USB Type-C ports on smartphones, tablets, and laptops, USB-C docking stations, wall chargers, and any Type-C/PD port that requires robust CC and SBU protection. The wide OVP range and small WLCSP package make it suitable for space-constrained portable designs.
When designing with this device, ensure the VDD supply is decoupled with a low-ESR 1uF ceramic capacitor placed close to the VDD ball. The exposed CSP land beneath the package should be soldered to a grounded copper pad for thermal dissipation and mechanical reliability.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes for the FUSB251UCX not found in the onsemi datasheet alone, optimized for engineers sourcing Type-C protection switches.
Bộ thay thế dễ dàng lắp đặt cho FUSB251UCX — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
FUSB251UCX
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →FUSB252UCX
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
FUSB251UCX Tỷ lệ tối đa & tính chất điện
| Chức năng | USB Type-C CC and SBU Protection Switch with OVP |
| Giao diện | I2C |
| Number of Channels | 4 (CC1, CC2, SBU1, SBU2) |
| Switch Type | SPST |
| Over-Voltage Protection | Yes (programmable threshold) |
| Dead-Battery Rd Support | Yes (CC pulled down with Rd) |
| Over-Current Protection | Yes |
| Tắt nhiệt | Yes |
| Khoảng nhiệt độ hoạt động | -40C to +85C (industrial, datasheet typical) |
| Hộp | 15-WLCSP (1.49 mm x 2.06 mm) |
| Kiểu lắp đặt | Surface Mount |
| Trạng thái RoHS | Compliant |
| Cấp MSL | 1 (per JEDEC J-STD-020) |
Cấu hình chân FUSB251UCX
| Chân A1 | CC1 — Configuration Channel 1, OVP-protected SPST switch |
| Chân A2 | CC2 — Configuration Channel 2, OVP-protected SPST switch |
| Chân A3 | NC — Not connected (per datasheet) |
| Chân B1 | SBU1 — Sideband Use 1, OVP-protected SPST switch |
| Chân B2 | SBU2 — Sideband Use 2, OVP-protected SPST switch |
| Chân B3 | VDD — Power supply input (decouple with 1uF low-ESR ceramic) |
| Chân C1 | GND — Ground |
| Chân C2 | SDA — I2C data line |
| Chân C3 | SCL — I2C clock line |
| Chân D1 | INT — Interrupt output (active low, fault indicator) |
| Chân D2 | EN — Enable input |
| Chân D3 | ADDR — I2C address select |
| Chân E1 | NC — Not connected (per datasheet) |
| Chân E2 | NC — Not connected (per datasheet) |
| Chân E3 | GND — Ground (thermal pad / substrate tie) |
Ứng dụng tiêu biểu
FUSB251UCX phù hợp cho 7 Áp dụngs: Smartphone USB-C Charging Port, USB-C Docking Station, USB-C Wall Charger (Source), Laptop USB-C Port Protection, Tablet USB-C Port, USB-C Power Bank, USB-C Display/Monitor Port.
Smartphone USB-C Charging Port
The FUSB251UCX sits between the USB Type-C receptacle and the smartphone's USB-PD controller, providing OVP protection on the CC1/CC2 detection lines and SBU1/SBU2 sideband lines. With 4 SPST switches that auto-enable on valid VDD, it isolates the PD controller from connector-level faults up to 20 V per USB Type-C spec. Dead-battery Rd pull-down lets a wall-charger source detect and power a depleted phone battery, satisfying USB Type-C attach detection. The 1.49x2.06 mm WLCSP fits inside the tight PCB stack of modern phones. TI TPS65987D and onsemi FUSB303 are common companion PD controllers.
Được đề xuất
USB-C Docking Station
In a USB-C docking station, the FUSB251UCX protects the host-facing Type-C port's CC and SBU lines from fault voltages that may appear if a user plugs a damaged cable or supply. The I2C interface enables the dock's MCU to monitor OVP, OCP, and thermal events and react by disabling downstream ports. With 4 channels of protected switching, the dock can multiplex SBU for analog audio or display alt-mode sideband signaling safely. The WLCSP package and industrial -40C to +85C temperature range suit always-on docking applications.
Được đề xuất
USB-C Wall Charger (Source)
USB-C wall chargers use the FUSB251UCX to provide protected CC1/CC2 detection paths so the charger's PD controller can advertise its power profile over USB-C. The dead-battery Rd support means a charger can power a device through the cable even when the device's battery is dead. OVP shields the charger's PD controller from voltage transients on the receptacle - critical for products sold globally with varying mains power quality. The small WLCSP footprint keeps the charger's PCB lean.
Được đề xuất
Laptop USB-C Port Protection
Laptops integrate multiple USB-C ports, each needing robust CC and SBU protection. The FUSB251UCX offers 4-channel SPST switching in a compact WLCSP, allowing one IC per port without consuming significant PCB real estate. OVP up to 20 V safeguards the laptop's downstream USB-PD controller from connector shorts and hot-plug transients. I2C enables the laptop's embedded controller to query fault status and re-enable ports after a transient OVP event.
Được đề xuất
Tablet USB-C Port
Tablets share many electrical protection needs with smartphones but at higher USB-PD power levels (up to 100 W). The FUSB251UCX provides OVP protection on CC1/CC2 and SBU1/SBU2 lines for the tablet's USB-PD controller, isolating faults at the receptacle before they reach the SoC. Dead-battery Rd support enables the tablet to charge from a depleted state - important for tablets that may sit unused for months. WLCSP compactness suits slim tablet designs.
Được đề xuất
USB-C Power Bank
USB-C power banks must protect their internal battery and USB-PD controller from connector-level faults on both input (sink) and output (source) ports. The FUSB251UCX's CC and SBU protection provides the OVP/OCP needed for safe bi-directional USB-C operation. Its small WLCSP footprint fits within the constrained PCB of a slim power bank. Dead-battery Rd ensures that even when the power bank's battery is empty, a source device can supply VBUS for recharging.
Được đề xuất
USB-C Display/Monitor Port
USB-C monitors accept DisplayPort alt-mode signals over USB-C and need protected CC and SBU lines for alt-mode negotiation. The FUSB251UCX isolates the monitor's USB-PD controller from receptacle faults while allowing SBU1/SBU2 analog pass-through for alt-mode sideband. I2C status reporting lets the monitor's MCU log fault events for diagnostics. The industrial temperature range supports always-on display installations.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho FUSB251UCX — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | FUSB251UCX | FUSB252UCX | TPD4S201YCAR |
|---|---|---|---|---|
| Package | 15-WLCSP (1.49x2.06 mm) | 15-WLCSP (1.49x2.06 mm) - same | 15-WLCSP (1.49x2.06 mm) - same | 12-DSBGA (1.2x1.4 mm) - different package |
| Brand | onsemi | onsemi | onsemi | Texas Instruments |
| Function | CC + SBU OVP switch (4-ch) | CC + SBU OVP switch (4-ch) | CC + SBU OVP switch (4-ch, enhanced) | CC + D+/D- short-to-VBUS protection (no SBU) |
| Channels | 4 (CC1, CC2, SBU1, SBU2) | 4 (CC1, CC2, SBU1, SBU2) | 4 (CC1, CC2, SBU1, SBU2) | 4 (CC1, CC2, D+, D-) |
| Interface | I2C | I2C | I2C | GPIO (no I2C) |
| Dead-Battery Rd | Yes | Yes | Yes | Yes |
| OCP | Yes | Yes | Yes | No (OVP only) |
| Thermal Shutdown | Yes | Yes | Yes | No |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
Bảo phân biệt quan trọng
- Integrated SBU1/SBU2 protection alongside CC1/CC2 (vsTPD4S201YCAR)
- I2C control with fault-status reporting (vsTPD4S201YCAR)
- WLCSP 1.49x2.06 mm footprint (vsTPD4S201YCAR)
Ghi chú thiết kế
Place the 1uF VDD decoupling MLCC within 1 mm of the VDD bump to minimize parasitic inductance and ensure clean VDD during fast OVP events. Use a low-ESR X7R ceramic (e.g., 10 V rated 0402) and route a wide, short power trace. Tie the WLCSP exposed substrate land to a grounded copper pour for both thermal relief and mechanical CSP solder joint reliability. Avoid routing CC and SBU traces near the primary side of any high-voltage converters on the same PCB.
Estimated: At 3.3 V VDD, each SPST switch conducts up to ~1 mA continuous CC current; total IC power dissipation is below 10 mW - thermal shutdown is unlikely under normal USB-C signaling but can trigger during sustained OVP clamp events. If thermal shutdown triggers, the device latches and requires VDD cycle to recover (verify with datasheet). Do not route the I2C SDA/SCL lines without 4.7 kohm pull-ups to VDD - missed pull-ups are the most common FUSB251UCX bring-up failure.
The 15-WLCSP exposed substrate land is the primary thermal path. For designs operating at -40C to +85C ambient with sustained OVP clamping, ensure the PCB land beneath the CSP has at least 10 mm^2 of copper tie to GND to keep junction rise below 20 C. The IC's thermal shutdown is internal and protects against fault heating, but a proper PCB land keeps the part out of thermal shutdown during normal operation.
Thông tin tuân thủ
RoHS compliant per onsemi product page. Not AEC-Q100 qualified - no automotive variant in FUSB251 family. REACH and halogen-free status not stated in verified web data (marked unknown).
