Overview
The SN74HC245PWT, produced by Texas Instruments, is an octal bus transceiver with 3-state outputs. This device is designed for asynchronous two-way communication between data buses, making it versatile for various digital logic applications. It features a wide operating voltage range of 2 V to 6 V, which allows it to be used in a variety of systems. The SN74HC245PWT is available in the TSSOP (PW) package, making it suitable for space-constrained designs.
Key Specifications
| Parameter | Min | 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 | ||
| TA Operating Free-Air Temperature | -40 | 85 | °C | |
| t pd Propagation Delay (A or B to A or B) at VCC = 5 V, CL = 50 pF | 15 | 21 | 32 | ns |
| IO Continuous Output Current | ±35 | mA | ||
| RθJA Junction-to-Ambient Thermal Resistance (TSSOP) | 99.7 | °C/W |
Key Features
- Wide operating voltage range of 2 V to 6 V.
- High-current 3-state outputs capable of driving bus lines directly or up to 15 LSTTL loads.
- Direction control (DIR) input to select data transmission direction between A and B buses.
- Output-enable (OE) input to disable the device and isolate the buses.
- Low drive and slow edge rates to minimize output ringing and overshoot.
- Available in TSSOP (PW) package for space-efficient designs.
Applications
The SN74HC245PWT is suitable for a variety of bus interface applications where output ringing is a concern. It can be used in systems requiring asynchronous two-way communication between data buses. Typical applications include:
- Microcontroller and system board interfaces.
- Data transmission and reception in digital systems.
- Bus isolation and control in complex digital circuits.
- LED and relay control circuits.
Q & A
- What is the operating voltage range of the SN74HC245PWT?
The operating voltage range is from 2 V to 6 V. - What is the purpose of the DIR input in the SN74HC245PWT?
The DIR input controls the direction of data transmission between the A and B buses. - How can the SN74HC245PWT be disabled to isolate the buses?
The device can be disabled by setting the OE (output-enable) input to a high voltage level. - What is the maximum continuous output current for the SN74HC245PWT?
The maximum continuous output current is ±35 mA. - What package type is the SN74HC245PWT available in?
The SN74HC245PWT is available in the TSSOP (PW) package. - Why is it important to use bypass capacitors with the SN74HC245PWT?
Bypass capacitors help prevent power disturbances and ensure stable operation by filtering out noise. - What are the thermal considerations for the SN74HC245PWT?
The junction-to-ambient thermal resistance (RθJA) for the TSSOP package is 99.7 °C/W. - How should unused inputs be handled in the SN74HC245PWT?
Unused inputs should be held at VCC or GND to ensure proper device operation. - What is the propagation delay for the SN74HC245PWT at VCC = 5 V and CL = 50 pF?
The propagation delay is between 15 ns and 32 ns. - Can the SN74HC245PWT drive LSTTL loads directly?
Yes, it can drive bus lines directly or up to 15 LSTTL loads.
