SN74CBTLV3257DR

• Four Channels of 2:1 SPDT Analog Bus switching, Non-Inverting
• 40Ω Switch resistance, 200M Hz bandwidth, 6.1ns Propagation Delay
• Partial-Power-Down Mode Isolates the Switch When Unpowered
• Single 2.3V to 3.6V supply, 10µA Quiescent and Operating Current
• 128mA Low-Level and -128mA High-Level Output Current
• 16-Pin SOIC, 9.9mm X 3.91mm X 1.75mm, Gold plating, Tape and reel, -40°C to 85°C

The Texas Instruments SN74CBTLV3257DR is a 3.3V four-channel 2:1 (SPDT) analog bus switch in a 16-pin SOIC. It is built from FET switches rather than buffered logic, so it passes signals with about 40Ω of on-resistance and adds essentially no propagation delay of its own beyond the 6.1ns specified, and it supports 200M Hz of bandwidth. The device operates from a single 2.3V to 3.6V supply at only 10µA and includes a partial-power-down mode, which isolates the switch when the supply is removed so it does not load a still-powered bus. The SN74CBTLV3257DR drives ±128mA and is rated from -40°C to 85°C.

FET bus switches are used to multiplex or isolate digital buses without adding a logic delay stage: selecting between two memory or peripheral devices on a shared bus, routing a JTAG or debug interface between targets, switching a lane between two connectors, and hot-swap isolation of a card from a live backplane. The partial-power-down feature is the key selection criterion for the SN74CBTLV3257DR, since it allows a subsystem to be powered off while its bus connections remain attached to a live bus. With 200M Hz of bandwidth it handles moderate-speed parallel buses and control lines rather than multi-gigabit serial links. Typical users are designers of networking equipment, embedded computing boards, storage controllers, and test fixtures.