SN74CB3Q3245PWR

• Eight Independent SPST FET Bus Switch channels, 8 Bits Wide
• 9Ω Switch on-resistance, 500M Hz Bandwidth
• 200ps Propagation delay; 7.5ns Turn-on Delay
• Single 2.3V to 3.6V supply, 1mA Nominal Supply Current
• 64mA Low-Level and -64mA High-Level Output Current
• 20-Pin TSSOP, 6.5mm X 4.4mm, Gold plating, Tape and reel, -40°C to 85°C, Active Production

The Texas Instruments SN74CB3Q3245PWR is a 3.3V eight-channel single-pole single-throw (SPST) FET bus switch in a 20-pin TSSOP. Because it switches with FETs rather than re-driving through logic, it adds only 200ps of propagation delay and about 9Ω of on-resistance, so a bus passes through it almost as if the switch were not there. It supports 500M Hz of bandwidth, operates from a single 2.3V to 3.6V supply at roughly 1mA, and drives ±64mA. The SN74CB3Q3245PWR has a 7.5ns turn-on delay and is rated from -40°C to 85°C.

An eight-bit FET bus switch is used to connect and disconnect a whole byte-wide bus under logic control: isolating a memory or peripheral bank, hot-swapping a card from a live backplane, sharing a bus between two controllers, and switching a debug or test port onto production signals. The near-zero added delay is the reason designers choose a FET switch over a bus transceiver, since inserting a buffer in a timed bus path can break setup and hold margins. With 500M Hz of bandwidth the SN74CB3Q3245PWR handles fast parallel buses and clock distribution as well as slower control lines. Users include designers of embedded computing and networking boards, storage and RAID controllers, telecom line cards, and automated test equipment.