1 Features

• High-bandwidth data path (up to 500 MHz)1

• 5-V tolerant I/Os with device powered up or

powered down

• Low and flat ON-state resistance (ron)

characteristics over operating range

(ron = 3 Ω typical)

• Supports input voltage beyond supply on data I/O

ports

– 0 to 5 V switching with 3.3 V VCC

– 0 to 3.3 V switching with 2.5 V VCC

• Bidirectional data flow with near-zero propagation

delay

• Low input or output capacitance minimizes loading

and signal distortion

(Cio(OFF) = 3.5 pF typical)

• Fast switching frequency (fOE = 20 MHz maximum)

• Data and control inputs provide undershoot clamp

diodes

• Low power consumption (ICC = 0.25 mA typical)

• VCC operating range from 2.3 V to 3.6 V

• Data I/Os support 0 to 5 V signaling levels (0.8 V,

1.2 V, 1.5 V, 1.8 V, 2.5 V, 3.3 V, and 5 V)

• Control inputs can be driven by TTL or

5 V/3.3 V CMOS outputs

• Ioff supports partial-power-down mode operation

• Latch-up performance exceeds 100 mA per JESD

78, Class II

2 Applications

• IP phones: wired and wireless

• Optical modules

• Optical networking: video over fiber and EPON

• Private branch exchange (PBX)

• WiMAX and wireless infrastructure equipment

• USB, differential signal interface

• Bus isolation

3 Description

The SN74CB3Q3305 device is a high-bandwidth FET

bus switch using a charge pump to elevate the

gate voltage of the pass transistor, providing a low

and flat ON-state resistance (ron). The low and flat

ON-state resistance allows for minimal propagation

delay and supports switching input voltage beyond

the supply on the data input/output (I/O) ports. The

device also features low data I/O capacitance to

minimize capacitive loading and signal distortion on

the data bus. Specifically designed to support highbandwidth

applications, the SN74CB3Q3305 device

provides an optimized interface solution ideally suited

for broadband communications, networking, and dataintensive

computing systems.

This device is fully specified for partial-power-down

applications using Ioff. The Ioff circuitry prevents

damaging current backflow through the device when

it is powered down. The device has isolation during

power off.

To ensure the high-impedance state during power up

or power down, OE should be tied to GND through a

pulldown resistor; the minimum value of the resistor

is determined by the current-sourcing capability of the

driver.