Overview
The SN74HC245PW is an octal bus transceiver with 3-state outputs, produced by Texas Instruments. This device is designed for asynchronous two-way communication between data buses, making it versatile for various digital circuit applications. It features a wide operating voltage range from 2 V to 6 V, which allows it to be used in a variety of systems. The SN74HC245PW is available in a TSSOP (Thin Shrink Small Outline Package) package, making it suitable for space-constrained designs.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| VCC Supply Voltage | 2 | 5 | 6 | V |
| VIH High-Level Input Voltage (VCC = 2 V) | 1.5 | V | ||
| VIH High-Level Input Voltage (VCC = 4.5 V) | 3.15 | V | ||
| VIH High-Level Input Voltage (VCC = 6 V) | 4.2 | V | ||
| VIL Low-Level Input Voltage (VCC = 2 V) | 0.5 | V | ||
| VIL Low-Level Input Voltage (VCC = 4.5 V) | 1.35 | V | ||
| VIL Low-Level Input Voltage (VCC = 6 V) | 1.8 | V | ||
| VO Output Voltage | 0 | VCC | V | |
| TA Operating Free-Air Temperature | -40 | 85 | °C | |
| t pd Propagation Delay (A or B to A or B, CL = 50 pF, VCC = 5 V) | 15 | 21 | 32 | ns |
| t pd Propagation Delay (OE to A or B, CL = 50 pF, VCC = 5 V) | 23 | 46 | 68 | ns |
Key Features
- Wide Operating Voltage Range: From 2 V to 6 V, making it compatible with various system voltages.
- High-Current 3-State Outputs: Capable of driving bus lines directly or up to 15 LSTTL loads.
- Direction Control: Data transmission can be controlled from the A bus to the B bus or vice versa using the DIR input.
- Output Enable: The OE input allows the device to be disabled, effectively isolating the buses.
- Low Drive and Slow Edge Rates: Minimizes output ringing, overshoot, and undershoot.
- Multiple Package Options: Available in TSSOP, SOIC, PDIP, SOP, and other packages.
Applications
- Bus Interface Applications: Ideal for asynchronous two-way communication between data buses.
- Digital Circuit Designs: Suitable for use in microcontroller, relay, and LED driver circuits.
- System Boards and Backplanes: Can be used to connect and manage data flow between different sections of a system.
- Embedded Systems: Useful in embedded systems where data needs to be transmitted between different modules.
Q & A
- What is the operating voltage range of the SN74HC245PW?
The operating voltage range is from 2 V to 6 V.
- How does the direction control work in the SN74HC245PW?
Data transmission can be controlled from the A bus to the B bus or vice versa using the DIR input.
- What is the purpose of the OE input in the SN74HC245PW?
The OE input allows the device to be disabled, effectively isolating the buses.
- What are the typical propagation delays for the SN74HC245PW?
For CL = 50 pF and VCC = 5 V, the propagation delay from A or B to A or B is typically 21 ns, and from OE to A or B is typically 46 ns.
- What are the thermal characteristics of the SN74HC245PW?
The junction-to-ambient thermal resistance (RθJA) for the TSSOP package is approximately 99.7 °C/W.
- Can the SN74HC245PW drive high-current loads?
Yes, it can drive up to 15 LSTTL loads and has high-current 3-state outputs.
- How should unused inputs be handled in the SN74HC245PW?
All unused inputs must be held at VCC or GND to ensure proper device operation.
- What are the recommended operating temperatures for the SN74HC245PW?
The operating free-air temperature range is from -40°C to 85°C.
- What is the input transition rise and fall time for the SN74HC245PW?
The input transition rise and fall time is 1000 ns for VCC = 2 V, 500 ns for VCC = 4.5 V, and 400 ns for VCC = 6 V.
- Can the SN74HC245PW be used in safety-critical applications?
No, it is not recommended for use in safety-critical applications without proper validation and testing.
