Overview
The MC74HCT245A, produced by onsemi, is a high-performance silicon-gate CMOS device designed for 2-way asynchronous communication between data buses. It is identical in pinout to the LS245 and can be used as a level converter for interfacing TTL or NMOS outputs to High Speed CMOS inputs. This 3-state noninverting transceiver features an active-low Output Enable pin, which places the I/O ports into high-impedance states, and a Direction control that determines the data flow direction between the A and B buses.
Key Specifications
| Parameter | Value | Units |
|---|---|---|
| Operating Voltage Range | 4.5 to 5.5 | V |
| Output Drive Capability | 15 LSTTL Loads | |
| Input Current | 1.0 | μA |
| Internal Gate Count | 76 Equivalent Gates | |
| Internal Gate Propagation Delay | 1.0 | ns |
| Power Dissipation Capacitance (Per Enabled Output) | 97 | pF |
| Maximum Output Propagation Delay (CL = 50 pF) | 17 to 34 | ns |
| Maximum Output Enable Time (RL = 1 kΩ, CL = 50 pF) | 31 to 63 | ns |
| Maximum Output Disable Time (RL = 1 kΩ, CL = 50 pF) | 21 to 45 | ns |
| Maximum Output Rise and Fall Time (CL = 50 pF) | 8 to 18 | ns |
| Input Capacitance | 10 to 15 | pF |
| Output/Input Capacitance | 20 to 25 | pF |
Key Features
- TTL/NMOS Compatible Input Levels
- Outputs Directly Interface to CMOS, NMOS, and TTL
- Active-Low Output Enable Pin for High-Impedance States
- Direction Control for Data Flow Between A and B Buses
- Low Power Consumption with High Speed Operation
- In Compliance with JEDEC Standard No. 7A
- Pb-Free Packages Available
- Protected from Damage Due to Static Discharge
Applications
The MC74HCT245A is suitable for various applications requiring 2-way asynchronous communication between data buses, including:
- Level conversion between TTL or NMOS outputs and High Speed CMOS inputs
- Interface between TTL and NMOS components and standard CMOS devices
- Data bus communication in digital systems
- High-speed data transmission in microprocessor and microcontroller systems
Q & A
- What is the primary function of the MC74HCT245A?
The MC74HCT245A is a 3-state noninverting transceiver used for 2-way asynchronous communication between data buses.
- What is the operating voltage range of the MC74HCT245A?
The operating voltage range is 4.5 to 5.5 V.
- How many LSTTL loads can the MC74HCT245A drive?
The device can drive up to 15 LSTTL loads.
- What is the purpose of the Direction control pin?
The Direction control determines whether data flows from A to B or from B to A.
- What is the function of the active-low Output Enable pin?
The active-low Output Enable pin places the I/O ports into high-impedance states.
- Is the MC74HCT245A protected against static discharge?
Yes, all inputs are protected from damage due to static discharge by diodes to VCC and ground.
- What are the typical propagation delays for the MC74HCT245A?
The maximum output propagation delay ranges from 17 to 34 ns for CL = 50 pF.
- What is the power dissipation capacitance per enabled output?
The power dissipation capacitance per enabled output is typically 97 pF at 25°C, VCC = 5.0 V.
- Is the MC74HCT245A compliant with any specific standards?
Yes, it is in compliance with the requirements defined by JEDEC Standard No. 7A.
- Are Pb-Free packages available for the MC74HCT245A?
Yes, Pb-Free packages are available.
