2 Description

The SN74CB3Q3244 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 (r_on). The low and flat ON-state resistance allows for minimal propagation delay and supports rail-to-rail switching 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 high-bandwidth applications, the SN74CB3Q3244 provides an optimized interface design for broadband communications, networking, and data-intensive computing systems.

The SN74CB3Q3244 is organized as two 4-bit bus switches with separate output-enable (1 OE, 2 OE) inputs. The device can be used as two 4-bit bus switches or as one 8-bit bus switch. When OE is low, the associated 4-bit bus switch is ON, and the A port is connected to the B port, allowing bidirectional data flow between ports. When OE is high, the associated 4-bit bus switch is OFF, and the high-impedance state exists between the A and B ports.

This device is fully specified for partial-power-down applications using I_off. The I_off circuitry prevents damaging current backflow through the device when powered down. The device has isolation during power off.

To make sure of the high-impedance state during power up or power down, OE must be tied to V_CC through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.