| State | USB Link | Current (5V) | Power | Temp Rise | | :--- | :--- | :--- | :--- | :--- | | Sleep (ASPM L1.2) | Suspend | 58 mA | 0.29 W | +2°C | | Idle (no trim) | Gen 2 (10G) | 320 mA | 1.6 W | +12°C | | Sequential Write (4KB) | Gen 2 (10G) | 890 mA | 4.45 W | +38°C | | Thermal Throttle (85°C) | Gen 1 (5G) | 610 mA | 3.05 W | N/A |
The 2021 datasheet provides updated power figures measured at 25°C ambient, with a Samsung PM981a 1TB NVMe SSD:
Unlike rigid, hard-wired bridge chips, the RTL9210B relies on an external SPI Flash memory chip to hold its operational firmware. Realtek provides a specialized mass-production configuration tool ( configure.cfg ) that allows manufacturers to modify hardware behavior without changing the physical board layout.
The RTL9210B won the “best balance” category in 2021 for low heat and high compatibility. rtl9210b datasheet 2021
Most chips required a jumper or a firmware flash to switch between NVMe and SATA drives. This one—the Realtek RTL9210B—claimed it could detect the protocol instantly. And the date: 2021. This wasn’t a legacy part. This was fresh silicon, built for the post-COVID world where everyone was building home labs and NAS boxes from spare parts.
The RTL9210B is a USB-to-SSD bridge controller developed by Realtek Semiconductor, a globally recognized leader in communications and multimedia ICs. In 2021, as the demand for high-speed external storage surged with the widespread adoption of NVMe SSDs and USB 3.2 Gen2 interfaces, the RTL9210B stood out from the competition due to its unique —capable of interfacing with both NVMe (PCIe) and SATA M.2 SSDs on a single platform.
The 2021 datasheet provides a full pin assignment table. Below are the critical groups required for a basic functional design. | State | USB Link | Current (5V)
She opened the PDF. It was 47 pages of electrical schematics, pinout diagrams, and timing charts. But tucked away on page 34 was a single line that changed everything: "Dual-Protocol Auto-Switch: PCIe to USB 3.2 Gen 2x2 and SATA – 20Gbps full duplex."
Some variants, such as the RTL9210BPD , even include support for USB Power Delivery 3.0 . RTL9210B-CG Datasheet 1.1 Arrowasia | PDF - Scribd
The controller is designed as a bridge between USB 3.1 Gen2 (10Gbps) and internal storage protocols. Specification USB 3.1 Gen2 (up to 10Gbps); compatible with USB 2.0/3.0 PCI Express Gen3 x2 (up to 16GT/s); compatible with Gen1 and Gen2 SATA Interface SATA Gen3 (up to 6Gbps); backward compatible with Gen1/Gen2 Connector Integrated Type-C support with orientation detection Protocols UASP (USB Attached SCSI) and BOT (Bulk Only Transfer) Package 68-pin QFN Green package Core Functionality Most chips required a jumper or a firmware
Compliant with PCI Express Base Specification Rev. 3.0 . In USB-to-PCIe mode, it supports PCIe Gen3 x2, providing up to 10Gbps bandwidth for NVMe SSDs.
The 2021 datasheet includes a 24-page PCB layout guide. Critical points: