Overview
The SN74HCT245DWRE4 is an octal bus transceiver with 3-state outputs, designed for asynchronous two-way communication between data buses. This device is part of the 74HCT series from Texas Instruments, which is compatible with TTL (Transistor-Transistor Logic) voltage levels. The SN74HCT245 allows data transmission from the A bus to the B bus or from the B bus to the A bus, depending on the logic level at the direction-control (DIR) input. The output-enable (OE) input can be used to disable the device, effectively isolating the buses.
Key Specifications
| Parameter | Min | Max | Unit | |
|---|---|---|---|---|
| VCC Supply Voltage | 4.5 | 5 | 5.5 | V |
| High-Level Input Voltage (VIH) | 3.15 | V (at VCC = 4.5 V) | ||
| Low-Level Input Voltage (VIL) | 1.35 | V (at VCC = 4.5 V) | ||
| Output Current (IO) | ±6 mA | (at VCC = 5 V) | ||
| Propagation Delay (tpd) | 14 | 30 | ns (at CL = 50 pF, VCC = 5.5 V) | |
| Input Current (II) | 1 µA | (maximum) | ||
| Supply Current (ICC) | 80 µA | (maximum at VCC = 5.5 V) | ||
| Operating Temperature (TA) | -40 | 85 | °C |
Key Features
- Operating voltage range from 4.5 V to 5.5 V, forgiving of 5-V power supply rail accuracy.
- High-current 3-state outputs drive bus lines directly or up to 15 LSTTL loads.
- Low power consumption with a maximum static supply current of 80 µA.
- Typical propagation delay of 14 ns and balanced output drive of ±6 mA at 5 V.
- Inputs are TTL-voltage compatible.
- Active low output enable (OE) and direction control (DIR) inputs.
- Center VCC and GND pin configurations to minimize high-speed switching noise.
Applications
- Factory Automation and Control
- Grid Infrastructure
- Electronic Point of Sale
- Multi-Function Printers
- Motor Drives
- Storage Systems
- Telecom Infrastructure
Q & A
- What is the operating voltage range of the SN74HCT245?
The operating voltage range is from 4.5 V to 5.5 V.
- What is the maximum propagation delay of the SN74HCT245?
The maximum propagation delay is approximately 30 ns at CL = 50 pF and VCC = 5.5 V.
- How many LSTTL loads can the outputs drive?
The outputs can drive up to 15 LSTTL loads.
- What is the typical supply current of the SN74HCT245?
The typical supply current is 80 µA maximum.
- What is the purpose of the OE and DIR inputs?
The OE (output enable) input can disable the device to isolate the buses, and the DIR (direction control) input determines the direction of data transmission between the A and B buses.
- Are the inputs TTL-voltage compatible?
- What is the significance of the center VCC and GND pin configurations?
The center VCC and GND pin configurations help minimize high-speed switching noise.
- What are some common applications of the SN74HCT245?
Common applications include factory automation, grid infrastructure, electronic point of sale, multi-function printers, motor drives, storage systems, and telecom infrastructure.
- What is the operating temperature range of the SN74HCT245?
The operating temperature range is from -40°C to 85°C.
- How does the SN74HCT245 handle power-up and power-down states?
To ensure the high-impedance state during power-up or power-down, the OE input should be tied to VCC through a pull-up resistor.
