SN74HCT245NG4 Texas Instruments Integrated Circuit (Dual-In-Line Packages) In Stock
Texas Instruments SN74HCT245NG4 is an octal non-inverting bus transceiver with 3-state outputs accepting 5.5 V supply in a 20-pin DIP package. It features direction control via the DIR pin and output-enable via the OE pin for bidirectional 8-bit data bus buffering. Available from stock with worldwide shipping.
- Manufacturer
- Texas Instruments
- Package
- Dual-In-Line Packages
- Pin Count
- 20
- Lifecycle
- ACTIVE
- Datasheet
- SN74HCT245NG4 Datasheet PDF
- Category
- Integrated Circuit
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of SN74HCT245NG4?
- Octal bidirectional 3-state bus transceiver with non-inverting data paths and separate DIR and OE controls for flexible 8-bit bus buffering
- HCT logic family accepts TTL-compatible input thresholds (1.2 V min V_IH) while operating from a 5 V supply, enabling direct interfacing between CMOS and TTL logic families
- 20-pin DIP package supports through-hole assembly and breadboard prototyping; drives up to ±25 mA per output for bus driving across multi-load PCB environments
What is SN74HCT245NG4 used for?
The SN74HCT245NG4 is used as a data bus buffer and level interface in 8-bit microprocessor systems, FPGA I/O expansion boards, and memory address/data bus isolation circuits where bidirectional data flow must be controlled between two segments of the same 5 V bus or between a 3.3 V CMOS source and a 5 V TTL load. Its through-hole DIP package is favored in prototyping environments and legacy industrial equipment where soldering through-hole components is standard practice.
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
Where can I find the SN74HCT245NG4 datasheet?
SN74HCT245NG4 Datasheet DownloadOfficial datasheet from Texas Instruments
What are equivalent replacements for SN74HCT245NG4?
Compatible alternatives and drop-in replacements for SN74HCT245NG4:
Frequently Asked Questions
How does SN74HCT245NG4's HCT logic family enable direct interfacing between 3.3 V CMOS outputs and 5 V TTL inputs?
The HCT logic family is designed to accept TTL-compatible input thresholds: V_IH minimum is 2 V and V_IL maximum is 0.8 V. A 3.3 V CMOS output swings to approximately 3.0 V high and 0.1 V low, which both satisfy the HCT input thresholds. The SN74HCT245NG4 then drives its outputs to full 5 V CMOS levels (typically 4.9 V high, 0.1 V low) at ±25 mA, completing the level translation from 3.3 V logic to 5 V TTL-compatible bus loads without an additional level shifter IC.
For an 8-bit bidirectional data bus in a microcontroller system, how do the DIR and OE pins control data flow in SN74HCT245NG4?
DIR (direction) pin controls which side of the 8-bit transceiver is the driver: DIR = High routes data from the A port to the B port, and DIR = Low routes data from B to A. The OE (output enable) pin, when asserted Low, enables all 8 3-state outputs; when OE is High, all outputs go into high impedance, effectively disconnecting the transceiver from the bus. This allows multiple transceivers to share the same bus by time-multiplexing the OE signal, with only one device driving the bus at a time.
How does SN74HCT245NG4 compare to SN74HC245 in systems powered at 5 V with mixed TTL and CMOS logic?
SN74HC245 has CMOS input thresholds (V_IH minimum is approximately 3.15 V at 5 V supply), which means a 5 V TTL output that only swings to 2.4 V high may not reliably switch the HC part. SN74HCT245NG4's HCT thresholds (V_IH minimum 2 V) guarantee correct operation with TTL outputs. In mixed TTL/CMOS 5 V systems, SN74HCT245NG4 is the correct choice wherever legacy TTL ICs or open-collector TTL drivers feed the bus.
What output drive capability does SN74HCT245NG4 provide when buffering a heavily loaded 8-bit data bus?
Each output of SN74HCT245NG4 can source or sink up to 25 mA, allowing a single transceiver to drive up to 50 bus receivers simultaneously in a standard 74HCT family board (each HCT input draws less than 1 µA). For typical backplane applications with 10 to 20 TTL loads at 0.4 mA per input, the 25 mA output drive provides a safety margin of 60× to 6×, ensuring valid logic levels across PCB trace lengths up to 30 cm without signal conditioning.
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About Texas Instruments
Texas Instruments (TI) is a global semiconductor company headquartered in Dallas, Texas. TI designs and manufactures analog and embedded processing chips used in industrial, automotive, consumer, communications, and enterprise systems.
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