The SN74CB3T3257 is a high-speed TTL-compatible FET multiplexer/demultiplexer with low ON-state resistance (ron), allowing for minimal propagation delay. The device fully supports mixed-mode signal operation on all data I/O ports by providing voltage translation that tracks VCC. The SN74CB3T3257 supports systems using 5-V TTL, 3.3-V LVTTL, and 2.5-V CMOS switching standards, as well as user-defined switching levels (see Figure 1).
●The SN74CB3T3257 is a 4-bit 1-of-2 multiplexer/demultiplexer with a single output-enable (OE)\ input. The select (S) input controls the data path of the multiplexer/demultiplexer. When OE\ is low, the 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 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 Ioff. The Ioff 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 VCC through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.
● Output Voltage Translation Tracks VCC
● Supports Mixed-Mode Signal Operation On All Data I/O Ports
● 5-V Input Down To 3.3-V Output Level Shift With 3.3-V VCC
● 5-V/3.3-V Input Down To 2.5-V Output Level Shift With 2.5-V VCC
● 5-V Tolerant I/Os With Device Powered-Up or Powered-Down
● Bidirectional Data Flow, With Near-Zero Propagation Delay
● Low ON-State Resistance (ron) Characteristics (ron = 5 Typical)
● Low Input/Output Capacitance Minimizes Loading (Cio(OFF) = 5 pF Typical)
● Data and Control Inputs Provide Undershoot Clamp Diodes
● Low Power Consumption (ICC = 20 µA Max)
● 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, 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 250 mA Per JESD 17
● ESD Performance Tested Per JESD 22
● 2000-V Human-Body Model (A114-B, Class II)
● 1000-V Charged-Device Model (C101)
● Supports Digital Applications: Level Translation, USB Interface, Memory Interleaving, Bus Isolation
● Ideal for Low-Power Portable Equipment
