InterChip USB

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InterChip USB (IC-USB or sometimes referred to as USB-IC, Inter-chip USB, or High-Speed Inter-Chip (HSIC)) is an addendum to the USB Implementer Forum's USB 2.0 specification. The USB 3.0 successor of HSIC is called SuperSpeed Inter-Chip (SSIC).[1]

IC-USB is intended as a low power variant of the standard physical USB interface, and is made possible by intending its use for direct chip to chip communications and by restricting the length of the IC-USB bus to no more than 10 cm in length. This results in a lower inductance and capacitance, and therefore lower power requirements.

IC-USB is being used primarily in embedded systems and standards. One of the most relevant areas of application is in mobile phones, where, for instance, ETSI (in specification TS 102 600)[2] has standardized on IC-USB as the official high speed interface for connections between the phone's main chipset and the SIM card or UICC card.

USB 2.0 High-Speed Inter-Chip (HSIC) is a chip-to-chip variant of USB 2.0 that eliminates the conventional analog transceivers found in normal USB. It was adopted as a standard by the USB Implementers Forum in 2007. The HSIC physical layer uses about 50% less power and 75% less board area compared to traditional USB 2.0. HSIC uses two signals at 1.2 V and has a throughput of 480 Mbit/s. Maximum PCB trace length for HSIC is 10 cm. It does not have low enough latency to support RAM sharing between two chips.[3][4]


The forum's Inter-Chip USB Supplement was released in March 2006. ETSI TS 102 600,[2] which is ETSI's USB implementation requirements specification, was first released in December 2007.


  1. ^ "Transitioning from USB 2.0 HSIC to USB 3.0 SSIC". Archived from the original on 7 October 2015. Retrieved 7 August 2015.
  2. ^ a b ETSI TS 102 600
  3. ^ "Interchip Connectivity: HSIC, UniPro, HSI, C2C, LLI... oh my!". Archived from the original on 19 June 2011. Retrieved 24 June 2011.
  4. ^ "USB High Speed Inter-Chip Interface". Archived from the original on 9 June 2011. Retrieved 24 June 2011.