SN74CBT3257C Series
5-V, 2:1 (SPDT), 4-channel FET bus switch with –2-V undershoot protection
Manufacturer: Texas Instruments
Catalog
5-V, 2:1 (SPDT), 4-channel FET bus switch with –2-V undershoot protection
Key Features
• Undershoot Protection for Off-Isolation on A and B Ports Up To .2 VBidirectional Data Flow, With Near-Zero Propagation DelayLow ON-State Resistance (ron) Characteristics (ron= 3Typical)Low Input/Output Capacitance Minimizes Loading and Signal Distortion (Cio(OFF)= 5.5 pF Typical)Data and Control Inputs Provide Undershoot Clamp DiodesLow Power Consumption (ICC= 3 µA Max)VCCOperating Range From 4 V to 5.5 VData 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 OutputsIoffSupports Partial-Power-Down Mode OperationLatch-Up Performance Exceeds 100 mA Per JESD 78, Class IIESD Performance Tested Per JESD 222000-V Human-Body Model (A114-B, Class II)1000-V Charged-Device Model (C101)Supports I2C Bus ExpansionSupports Both Digital and Analog Applications: USB Interface, Bus Isolation, Low-Distortion Signal GatingUndershoot Protection for Off-Isolation on A and B Ports Up To .2 VBidirectional Data Flow, With Near-Zero Propagation DelayLow ON-State Resistance (ron) Characteristics (ron= 3Typical)Low Input/Output Capacitance Minimizes Loading and Signal Distortion (Cio(OFF)= 5.5 pF Typical)Data and Control Inputs Provide Undershoot Clamp DiodesLow Power Consumption (ICC= 3 µA Max)VCCOperating Range From 4 V to 5.5 VData 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 OutputsIoffSupports Partial-Power-Down Mode OperationLatch-Up Performance Exceeds 100 mA Per JESD 78, Class IIESD Performance Tested Per JESD 222000-V Human-Body Model (A114-B, Class II)1000-V Charged-Device Model (C101)Supports I2C Bus ExpansionSupports Both Digital and Analog Applications: USB Interface, Bus Isolation, Low-Distortion Signal Gating
Description
AI
The SN74CBT3257C is a high-speed TTL-compatible FET multiplexer/demultiplexer with low ON-state resistance (ron), allowing for minimal propagation delay. Active Undershoot-Protection Circuitry on the A and B ports of the SN74CBT3257C 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 SN74CBT3257C 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 Iofffeature 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 VCCthrough a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.
The SN74CBT3257C is a high-speed TTL-compatible FET multiplexer/demultiplexer with low ON-state resistance (ron), allowing for minimal propagation delay. Active Undershoot-Protection Circuitry on the A and B ports of the SN74CBT3257C 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 SN74CBT3257C 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 Iofffeature 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 VCCthrough a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.
