JMS539 PDF – USB to SATA II 3.0G Bridge Controller

This post explains for the bridge controller. A USB to SATA II 3.0G bridge controller is an integrated circuit or controller chip that serves as an interface between a USB (Universal Serial Bus) port and a SATA II (Serial ATA) storage device. It enables the connection of SATA II hard drives or solid-state drives (SSDs) to a computer or other device via a USB interface.

The Part Number is JMS539.

The function of this semiconductor is SuperSpeed USB to SATA II 3.0G Bridge Controller.

Manufacturer: JMicron

Preview images :JMS539 pdf


The JMS539 is a bridge controller, which translates the communication protocol between SATA II 3.0G and SuperSpeed USB commands. The integrated 60MIPS 8051, SATA II, Hi-Speed USB and SuperSpeed USB technology enable users to perform SuperSpeed USB to SATA II 3.0G, applications in a signal chip.

In this chip, the Hi-Speed/SuperSpeed USB controller supports the USB Mass Storage Class Bulk-Only
Transport Specification.

USB to SATA II 3.0G bridge controllers are commonly used in external hard drive enclosures, docking stations, or adapter cables that enable the connection of SATA II storage devices to computers or other devices with USB ports. They provide a convenient and efficient way to access and utilize SATA II storage devices via USB interfaces.[…]


JMS539 manual


• Complies with Gen2i/Gen2m of Serial ATA II Electrical Specification 2.6
• Supports SATA II Asynchronous Signal Recovery (Hot Plug) feature
• Complies with USB 3.0 Specification, USB Mass Storage Class, Bulk-Only Transport Specification
• Supports USB Super-Speed/High-Speed/Full-Speed Operation
• Supports USB HID operation
• Supports USB2.0/USB3.0 power saving mode
• Supports AES-128/256 for data encryption over USB2.0/USB3.0
• Supports external SPI NVRAM for Vendor VID/PID of USB2.0/USB3.0 device controller
• Supports ATA/ATAPI PACKET command set
• 12 GPIOs for customization
• Provides hardware control PWM

JMS539 Datasheet