The Realtek RTL9210B-CG is a high-performance, dual-protocol USB-to-PCIe (NVMe) and USB-to-SATA (AHCI) bridge for portable SSDs, featuring automatic protocol detection. Key features include up to 10Gbps transfer speeds for NVMe and 6Gbps for SATA, integrated USB Type-C support, UASP/TRIM command handling, and extensive power management. For detailed technical specifications, visit RTL9210B-CG - Realtek
The Realtek RTL9210B-CG is a dual-protocol USB bridge controller that enables high-speed data transfer between a USB host and either NVMe (PCI Express) or SATA storage devices. Key Technical Specifications (2021 Datasheet)
The controller is designed as a bridge between USB 3.1 Gen2 (10Gbps) and internal storage protocols. Specification USB Interface 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
Dual-Protocol Switching: Using the PEDET interface of the M.2 mechanical slot, the RTL9210B-CG
automatically switches between USB-to-PCIe and USB-to-SATA modes. Storage Support:
NVMe: Supports NVM Express Base Specification Rev. 1.3 with an embedded driver in RAM/ROM/SPI Flash.
SATA: Acts as a SATA host supporting the AHCI (Advanced Host Controller Interface) for HDDs and SSDs.
Power Management: Features a built-in algorithm to balance performance and power consumption, including support for LTR (Latency Tolerance Reporting) and ASPM L1 substates. rtl9210b datasheet 2021
Efficiency Features: Native support for TRIM commands ensures long-term SSD health by allowing proper garbage collection over USB. Performance and Compatibility RTL9210B-CG - Realtek
Realtek RTL9210B Go to product viewer dialog for this item. is a high-performance USB bridge controller
that gained significant popularity in 2021 for its unique ability to support both
M.2 SSDs in a single device. This "dual-protocol" capability makes it a versatile choice for external drive enclosures. Key Specifications from the 2021 Datasheet Interface Bridge : USB 3.2 Gen 2 to PCIe Gen3 x2 or SATA Gen3. (SuperSpeed Plus). PCIe (NVMe) bandwidth via 2 lanes (PCIe Gen3 x2). bandwidth. Automatic Switching : Features a
interface that allows the controller to automatically detect and switch between USB-to-PCIe and USB-to-SATA modes depending on the installed drive. Power Management
: Supports PCIe L1.Off/L1.Snooze and USB link power management to reduce energy consumption. : Supports both Bulk Only Transfer (BOT) USB Attached SCSI Protocol (UASP) for improved data transfer efficiency. Drive Features : Fully supports S.M.A.R.T.
commands, which are essential for maintaining SSD health and performance over time. Physical and Electrical Characteristics : 68-pin QFN "Green" package. Regulators UASP (USB Attached SCSI Protocol) – mandatory for
: Built-in switching regulator (5V to 1V) and LDO (5V to 3.3V), reducing the need for external power components. Clock Support : Supports a 25MHz crystal clock Customization : Provides interfaces for , along with support for customized LEDs. Comparison with RTL9210 (Non-B version)
The "B" revision introduced critical updates over the original RTL9210: Dual Protocol : While the original RTL9210 often supported only NVMe, the adds native SATA support. Efficiency
: The B-series typically features lower minimum power draw and fixed errata from the previous generation. Where to Find More Difference between these nvme enclosures : r/UsbCHardware
The Realtek RTL9210B is a highly popular controller chip used in USB 3.2 Gen 2 (10Gbps) to PCI Express NVMe bridge adapters (enclosures/M.2 docks). Because Realtek primarily supplies data sheets under Non-Disclosure Agreements (NDAs) to manufacturers, the full "official" 2021 datasheet is rarely found publicly.
However, based on the public technical specifications, firmware release notes, and developer documentation released around 2021, here is a comprehensive guide to the RTL9210B.
The RTL9210B is firmware-dependent. The 2021 datasheet references firmware version 1.23.x as the initial production release, with key capabilities:
Later 2021 revisions (firmware 1.27+) added: reducing BOM cost and PCB area.
Flashing procedure (from application note AN-2021-09):
Via USB firmware update mode (hold RESET# and GPIO12 low during power-on) or using the Realtek Flash Tool over UART.
The RTL9210B is not a simple protocol converter; it contains several key internal blocks as detailed in the 2021 block diagram:
A key advantage touted in the 2021 datasheet is the integrated power management unit (PMU). It generates all required core and I/O voltages from a single 3.3V or 5V input, reducing BOM cost and PCB area.
The RTL9210B requires a 3.3V power input for the controller itself, but the NVMe drive requires 3.3V at high amperage.
Published: Mid-2021 Review | Part Number: RTL9210B-VC / RTL9210B-CG
Vendor: Realtek Semiconductor Corp.
The 2021 datasheet provides updated power figures measured at 25°C ambient, with a Samsung PM981a 1TB NVMe SSD:
| 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 |
Critical 2021 Note: The RTL9210B will begin thermal throttling at 85°C junction temperature, reducing PCIe width from x2 to x1. Without a copper pad under the QFN, the chip will hit 105°C and shut down within 90 seconds of continuous writing.