• SN74CBT3253C Functionally Identical toIndustry-Standard ’3253 Function
• Undershoot Protection for Off-Isolation on A and B Ports up to -2 V
• Bidirectional Data Flow, With Near-Zero Propagation Delay
• Low ON-State Resistance (r_on) Characteristics (r_on = 3 Typical)
• Low Input/Output Capacitance Minimizes Loading and Signal Distortion (C_io(OFF) = 5.5 pF Typical)
• Data and Control Inputs Provide Undershoot Clamp Diodes
• Low Power Consumption (I_CC = 3 µA Max)
• V_CC Operating Range From 4 V to 5.5 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, 5 V)
• Control Inputs Can Be Driven by TTL or 5-V/3.3-V CMOS Outputs
• I_off Supports Partial-Power-Down Mode Operation
• Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II
• ESD Performance Tested Per JESD 22
  • 2000-V Human-Body Model (A114-B, Class II)
  • 1000-V Charged-Device Model (C101)
• Supports I²C Bus Expansion
• Supports Both Digital and Analog Applications: USB Interface, Bus Isolation, Low-Distortion Signal Gating

DESCRIPTION/ORDERING INFORMATION

The SN74CBT3253C is a high-speed TTL-compatible FET multiplexer/demultiplexer with low ON-state resistance (r_on), allowing for minimal propagation delay. Active Undershoot-Protection Circuitry on the A and B ports of the SN74CBT3253C provides protection for undershoot up to -2 V by sensing an undershoot event and ensuring that the switch remains in the proper OFF state.

The SN74CBT3253C is organized as two 1-of-4 multiplexer/demultiplexers with separate output-enable (1OE, 2OE) inputs. The select (S0, S1) inputs control the data path of each multiplexer/demultiplexer. When OE is low, the associated multiplexer/demultiplexer is enabled, and the A port is connected to the B port, allowing bidirectional data flow between ports. When OE is high, the associated multiplexer/demultiplexer is disabled, and a 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 feature ensures that damaging current will not 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 V_CC through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver