Overview
The SN74HC240N is an octal buffer and line driver produced by Texas Instruments. This component is designed to enhance the performance and density of 3-state memory address drivers, clock drivers, and bus-oriented receivers and transmitters. The device is organized as two 4-bit buffers/drivers with separate output-enable (OE) inputs. When the OE input is low, the device passes inverted data from the A inputs to the Y outputs. When the OE input is high, the outputs are in the high-impedance state, which is crucial for managing bus lines and memory address registers efficiently.
Key Specifications
| Parameter | Min | Nom | Max |
|---|---|---|---|
| VCC Supply Voltage | 2 V | 5 V | 6 V |
| VIH High-Level Input Voltage (VCC = 2 V) | 1.5 V | 1.5 V | 1.5 V |
| VIH High-Level Input Voltage (VCC = 4.5 V) | 3.15 V | 3.15 V | 3.15 V |
| VIH High-Level Input Voltage (VCC = 6 V) | 4.2 V | 4.2 V | 4.2 V |
| VIL Low-Level Input Voltage (VCC = 2 V) | 0.5 V | 0.5 V | 0.5 V |
| VIL Low-Level Input Voltage (VCC = 4.5 V) | 1.35 V | 1.35 V | 1.35 V |
| VIL Low-Level Input Voltage (VCC = 6 V) | 1.8 V | 1.8 V | 1.8 V |
| Operating Temperature Range | -40°C | 85°C | |
| Propagation Delay (tpd) at VCC = 2 V | 50 ns | 100 ns | 150 ns |
| Propagation Delay (tpd) at VCC = 4.5 V | 10 ns | 20 ns | 30 ns |
| Propagation Delay (tpd) at VCC = 6 V | 9 ns | 17 ns | 25 ns |
| Output Drive at 5 V | ±6 mA | ||
| Input Current (max) | 1 µA | ||
| Power Consumption (ICC max) | 80 µA |
Key Features
- Wide operating voltage range of 2 V to 6 V
- High-current outputs drive up to 15 LSTTL loads
- Low power consumption, 80 µA max ICC
- Typical propagation delay (tpd) of 9 ns at VCC = 6 V
- ±6 mA output drive at 5 V
- Low input current of 1 µA max
- 3-state outputs drive bus lines or buffer memory address registers
Applications
The SN74HC240N is suitable for various applications, including:
- 3-state memory address drivers
- Clock drivers
- Bus-oriented receivers and transmitters
- General-purpose buffering and line driving in digital systems
Q & A
- What is the operating voltage range of the SN74HC240N?
The operating voltage range is from 2 V to 6 V.
- How many LSTTL loads can the high-current outputs drive?
The high-current outputs can drive up to 15 LSTTL loads.
- What is the typical propagation delay at VCC = 6 V?
The typical propagation delay (tpd) at VCC = 6 V is 9 ns.
- What is the output drive capability at 5 V?
The output drive capability at 5 V is ±6 mA.
- What is the maximum input current?
The maximum input current is 1 µA.
- What is the maximum power consumption?
The maximum power consumption (ICC) is 80 µA.
- How do the 3-state outputs function?
The 3-state outputs drive bus lines or buffer memory address registers and can be in a high-impedance state when the OE input is high.
- What is the operating temperature range of the SN74HC240N?
The operating temperature range is from -40°C to 85°C.
- What types of packages are available for the SN74HC240N?
The SN74HC240N is available in PDIP (N), SOIC (DW), SOP (NS), SSOP (DB), and TSSOP (PW) packages.
- How are the outputs controlled in the SN74HC240N?
The outputs are controlled by separate output-enable (OE) inputs. When OE is low, the device passes inverted data from the A inputs to the Y outputs. When OE is high, the outputs are in the high-impedance state.
