Overview
The SN74LVC257ADBR is a quadruple 2-line to 1-line data selector and multiplexer produced by Texas Instruments. This device is designed to operate within a voltage range of 1.65V to 3.6V, making it suitable for a variety of digital signal processing applications. It features 3-state outputs that do not load the data lines when the output-enable (OE) input is at a high logic level, which is particularly useful in bus-organized systems. The device is also capable of acting as a translator in mixed 3.3V and 5V system environments due to its input voltage tolerance up to 5.5V.
Key Specifications
| Parameter | Min | Max | Unit |
|---|---|---|---|
| VCC Supply Voltage | 1.65 | 3.6 | V |
| VI Input Voltage | 0 | 5.5 | V |
| VO Output Voltage | 0 | VCC | V |
| VIH High-Level Input Voltage | 0.65 × VCC (1.65V to 1.95V) | 2 (2.7V to 3.6V) | V |
| VIL Low-Level Input Voltage | 0.35 × VCC (1.65V to 1.95V) | 0.8 (2.7V to 3.6V) | V |
| IOH High-Level Output Current | -4 (at VCC = 1.65V) | -24 (at VCC = 3V) | mA |
| IOL Low-Level Output Current | 4 (at VCC = 1.65V) | 24 (at VCC = 3V) | mA |
| tpd Propagation Delay (A or B to Y) | 1 | 4.6 | ns (at VCC = 3.3V) |
| TA Operating Free-Air Temperature | -40 | 85 | °C |
Key Features
- Operates from 1.65V to 3.6V supply voltage.
- Inputs accept voltages up to 5.5V, making it suitable for mixed 3.3V and 5V system environments.
- Maximum propagation delay of 4.6 ns at 3.3V, suitable for high-speed applications.
- 3-state outputs that do not load the data lines when the output-enable (OE) input is at a high logic level.
- High drive capability with balanced output drive.
- ESD protection and overvoltage tolerance on inputs.
Applications
The SN74LVC257ADBR is useful in various digital signal processing applications, including:
- Digital signal data selectors and multiplexers.
- Level translation in mixed 3.3V and 5V system environments.
- Bus-organized systems where 3-state outputs are necessary.
- High-speed applications requiring low propagation delays.
Q & A
- What is the operating voltage range of the SN74LVC257ADBR?
The SN74LVC257ADBR operates from 1.65V to 3.6V.
- What is the maximum input voltage tolerance for this device?
The inputs can tolerate voltages up to 5.5V.
- What is the maximum propagation delay at 3.3V supply voltage?
The maximum propagation delay is 4.6 ns at 3.3V supply voltage.
- What is the purpose of the 3-state outputs in this device?
The 3-state outputs do not load the data lines when the output-enable (OE) input is at a high logic level.
- Can this device be used in mixed 3.3V and 5V system environments?
Yes, it can be used as a translator in mixed 3.3V and 5V system environments.
- What is the recommended operating temperature range for this device?
The recommended operating temperature range is from -40°C to 85°C.
- How should unused inputs be handled to ensure proper device operation?
Unused inputs must be held at VCC or GND to ensure proper device operation.
- What is the significance of the output-enable (OE) input in this device?
The output-enable (OE) input controls the 3-state outputs; when OE is high, the outputs are in a high-impedance state.
- What are some common applications of the SN74LVC257ADBR?
Common applications include digital signal data selectors, multiplexers, level translation, and high-speed applications.
- How should the layout be designed to optimize the performance of this device?
The layout should avoid bus contention, use GND flood fill for improved signal isolation and noise reduction, and place bypass capacitors close to the device.
