Circuit Protection For IEEE 1394 Interfaces

The IEEE1394 interface is a serial standard developed by Apple, commonly known as Firewire. Like USB, IEEE1394 also supports hot-plugging of peripherals, which can provide power for peripherals, eliminating the need for the peripherals' own power supply. It can connect to multiple different devices and support synchronous data transmission. Widely used in local area multimedia interconnection, such as the interconnection of PCs, cameras, video recorders, printers, scanners, etc.

The cable specified by IEEE1394 is a 6-core wire. The outer layer of the cable has a total shielding layer. There are two pairs of shielded twisted pairs, one pair is used to transmit data, and the other pair is used to transmit clock signals.

A pair of power lines to power devices in wait mode on the bus, or directly to low-power peripherals. Handheld devices use softer cables, remove the power cord, and use a 4-pin interface.

 Yint has designed a low-cost ESD protection solution specifically for the IEEE1394 interface. 

IEEE 1394 uses a low-voltage differential signaling system (operating voltage between 1.20V and 2.00V) with a maximum data transfer rate of 400 Mbps (1394a) to 1,600 Mbps (1394b). When reaching this data rate range, the capacitance of the suppressor should be minimized. Signal lines that need to be protected from ESD include: TPA+, TPA-, TPB+, and TPB-. The 30VDC power bus also needs to be protected from ESD and overcurrent.

 Solution Description:

Multilayer varistors are used on the power bus to protect it from ESD, while a PTC is used to provide resettable overcurrent protection.

 Supporting solutions:

In addition to the above suggestions, the YINT product portfolio also offers other solutions. For example, a leaded PTC can be used instead of an SMD type product, or a TVS diode can be used instead of an MLV.

IEC61000-4-2 is the most suitable standard specification for this interface. This test demonstrates that the end product is not susceptible to ESD hazards.