SN74HCT244DBRG4 Texas Instruments Integrated Circuit (Small Outline Packages) In Stock
The SN74HCT244DBRG4 is an 8-channel non-inverting bus buffer and line driver in the HCT logic family, featuring tri-state outputs controlled by two active-low output-enable inputs, housed in a 20-pin SSOP package. It operates from a 4.5 V to 5.5 V supply and accepts TTL-level inputs, making it ideal for interfacing 5 V TTL logic to CMOS bus systems. Suited for address buffering, memory bus expansion, and driving high-capacitance bus loads in industrial and computing applications.
- Manufacturer
- Texas Instruments
- Package
- Small Outline Packages
- Pin Count
- 20
- Lifecycle
- OBSOLETE
- Datasheet
- SN74HCT244DBRG4 Datasheet PDF
- Category
- Integrated Circuit
- Temp Range
- -40.0°C to 85.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of SN74HCT244DBRG4?
- 8-channel non-inverting tri-state buffer compatible with TTL input levels
- HCT family: 4.5 V to 5.5 V supply, bridging TTL and CMOS logic families
- Two active-low output-enable (OE) inputs for independent half-channel control
- Output drive capability: 6 mA sink / 6 mA source per channel
- Low propagation delay: typically 7 ns at 5 V and 50 pF load
- 20-pin SSOP package for compact SMD layouts
What is SN74HCT244DBRG4 used for?
The SN74HCT244DBRG4 is widely used to buffer address and data bus lines in microprocessor and microcontroller systems, where it isolates the CPU outputs from the capacitive loading of long PCB traces or multiple peripheral devices. Its TTL-compatible input thresholds make it a natural choice for interfacing legacy 5 V TTL logic modules to HCT or HCMOS bus structures in industrial automation and telecommunications equipment. It is also employed in memory expansion boards and FPGA I/O expansion circuits requiring unidirectional 8-bit bus isolation.
What are the specifications of SN74HCT244DBRG4?
| YTEOL | 0 |
| Control Type | ENABLE LOW |
| Count Direction | UNIDIRECTIONAL |
| Family | HCT |
| JESD-30 Code | R-PDSO-G20 |
| JESD-609 Code | e4 |
| Load Capacitance (CL) | 50pF |
| Logic IC Type | BUS DRIVER |
| Max I(ol) | 0.006A |
| Number of Bits | 4 |
| Number of Functions | 2 |
| Number of Ports | 2 |
| Output Characteristics | 3-STATE |
| Output Polarity | TRUE |
| Package Body Material | PLASTIC/EPOXY |
| Package Equivalence Code | SSOP20,.3 |
| Package Shape | RECTANGULAR |
| Package Style | SMALL OUTLINE, SHRINK PITCH |
| Packing Method | TR |
| Peak Reflow Temperature (Cel) | 260 |
| Power Supply Current-Max (ICC) | 0.16mA |
| Prop. Delay@Nom-Sup | 35ns |
| Propagation Delay (tpd) | 56ns |
| Qualification Status | Not Qualified |
| Supply Voltage-Max (Vsup) | 5.5V |
| Supply Voltage-Min (Vsup) | 4.5V |
| Supply Voltage-Nom (Vsup) | 5V |
| Surface Mount | YES |
| Technology | CMOS |
| Temperature Grade | INDUSTRIAL |
| Terminal Finish | NICKEL PALLADIUM GOLD |
| Terminal Form | GULL WING |
| Terminal Pitch | 0.65mm |
| Terminal Position | DUAL |
| Time@Peak Reflow Temperature-Max (s) | 30 |
| Package | Small Outline Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| Moisture Sensitivity Level | MSL 1 |
| HTS Code | 8542.39.00.60 |
Where can I find the SN74HCT244DBRG4 datasheet?
SN74HCT244DBRG4 Datasheet DownloadOfficial datasheet from Texas Instruments
What are equivalent replacements for SN74HCT244DBRG4?
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
How do the two OE pins on SN74HCT244DBRG4 allow partial bus control?
SN74HCT244DBRG4 has two separate active-low output-enable pins, each controlling 4 of the 8 output channels. By asserting one OE pin while leaving the other deasserted, a designer can independently enable or tri-state the upper or lower nibble of the bus, enabling partial word transfers or multiplexed bus access without external logic gates. Both OE pins are compatible with TTL drive levels from 3.3 V or 5 V logic controllers.
What output drive current can SN74HCT244DBRG4 supply, and how many CMOS inputs can it drive?
Each output channel of SN74HCT244DBRG4 can sink 6 mA and source 6 mA, which is sufficient to drive approximately 50 standard CMOS inputs with 10 pF input capacitance each, or to drive one 50 pF bus trace without significant signal degradation. In practice, with a 50 pF load capacitance, the propagation delay is typically 7 ns at 5 V supply, making it suitable for bus speeds up to several tens of megahertz.
Is SN74HCT244DBRG4 suitable for interfacing a 3.3 V microcontroller to a 5 V TTL legacy bus?
SN74HCT244DBRG4 accepts input voltages above 2 V as a logic high, so a 3.3 V microcontroller driving SN74HCT244 inputs will typically meet this threshold. However, the device requires a 4.5 V to 5.5 V VCC to properly swing its outputs to TTL-compatible 5 V levels, so it effectively acts as a 3.3 V input to 5 V output level translator when powered from a 5 V rail. Designers should verify the source impedance and confirm the 3.3 V output levels exceed the 2 V minimum input high threshold across the -40°C to 85°C operating range.
How does the 20-pin SSOP package of SN74HCT244DBRG4 compare to the SOIC version for high-density board designs?
The 20-pin SSOP package has a 0.65 mm lead pitch and a body width of approximately 5.3 mm, occupying about 8.7 mm × 6.2 mm on the PCB. The equivalent 20-pin SOIC package has a 1.27 mm pitch and a 7.5 mm body, taking roughly 12.8 mm × 10.3 mm — more than 2× the area. For high-density bus buffer arrays on compact PCBs, the SSOP saves significant board real estate at the cost of requiring finer solder paste apertures and more precise placement.
Which bus expansion scenario benefits most from the unidirectional architecture of SN74HCT244DBRG4 versus a bidirectional transceiver?
A unidirectional buffer like SN74HCT244DBRG4 is most beneficial in address bus expansion, where signals always flow in one direction — from the CPU to memory address decoders and peripherals. In this scenario, direction control logic is unnecessary, eliminating one signal line and simplifying the design compared to a bidirectional transceiver such as SN74HCT245. The 8-channel drive capability and 6 mA output current are sufficient to fan out to 8 or more memory chip address inputs simultaneously at bus speeds up to 25 MHz.
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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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