Part A
74AC244SCX
Fairchild Semiconductor
- Lifecycle
- Active
- Stock
- 2840 PCS
- Package
- SOIC-W-20
- Series
- Logic - Buffers, Drivers, Receivers, Transceivers
Replacement verdict
Not a drop-in replacement
The 74AC244SCX and 74AC241SC are not functionally interchangeable. Although both are octal AC-series buffers in SOIC-20 packages, the 74AC244SCX provides non-inverting outputs with dual active-low output enables, while the 74AC241SC provides inverting outputs with a mixed enable scheme of active-low and active-high control. These differences in output polarity and enable logic prevent direct substitution without redesigning the surrounding control and signal-path circuitry.
Different output polarity
Different enable logic
Different logic function
Different signal path
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74AC244SCX | 74AC241SC | Why it matters |
|---|---|---|---|
| Logic Function | Octal Buffer/Line Driver, non-inverting, with 3-state outputs | Octal Buffer/Line Driver, inverting, with 3-state outputs | Determines output polarity; a non-inverting buffer cannot directly replace an inverting buffer without logic changes. |
| Output Polarity | Non-inverting (Y = A) | Inverting (Y = A̅) | Affects signal phase through the device; critical for functional substitutability in a circuit. |
| Enable Control Configuration | Two active-LOW output enables (1OE, 2OE) | One active-LOW and one active-HIGH output enable (1OE̅, 2OE) | Different enable logic requires different control signal polarity, affecting board-level compatibility. |
| Number of Channels | 8 (two 4-bit groups) | 8 (two 4-bit groups) | Channel count must match for pin-to-pin functional replacement. |
| Output Type | 3-state | 3-state | 3-state outputs allow bus sharing; both devices support this, aiding substitutability. |
| Supply Voltage Range | 2.0 V to 6.0 V | 2.0 V to 6.0 V | Compatible supply range ensures both parts can operate in the same system voltage domain. |
| Logic Family | AC (Advanced CMOS) | AC (Advanced CMOS) | Same logic family ensures comparable speed, drive, and input/output thresholds. |
| Package | SOIC-20 (SOP-20) | SOIC-20 (SOP-20) | Identical package footprint allows direct PCB placement without layout changes. |
| Pin Count | 20 | 20 | Matching pin count is required for drop-in replacement on the same footprint. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Same temperature range ensures both parts meet the same environmental requirements. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74AC244SCX | 74AC241SC |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC,onsemi |
| Series | 74AC | 74AC |
| Part Status | Active | Obsolete |
| Logic Type | Buffer, Non-Inverting | Buffer, Non-Inverting |
| Number of Elements | 2 | 2 |
| Number of Bits per Element | 4 | 4 |
| Output Type | 3-State | 3-State |
| Current - Output High Low | 24mA, 24mA | 24mA, 24mA |
| Voltage - Supply | 2V ~ 6V | 2V ~ 6V |
| Operating Temperature | -40°C ~ 85°C (TA) | -40°C ~ 85°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the 74AC244SCX and 74AC241SC?
The 74AC244SCX is an octal buffer/line driver with 3-state outputs from the AC family, while the 74AC241SC is an octal buffer/line driver with 3-state outputs that also includes a complementary output enable function. Both are designed for high-speed CMOS logic applications.
What is the main functional difference between the 74AC244SCX and 74AC241SC?
The 74AC244SCX has two active-low output enable pins (1OE and 2OE), each controlling four outputs. The 74AC241SC has one active-low output enable (1OE) and one active-high output enable (2OE), allowing independent control of two 4-bit groups with opposite polarity enables.
Are the 74AC244SCX and 74AC241SC pin-compatible?
No, they are not pin-compatible. The 74AC244SCX uses two active-low enables, while the 74AC241SC uses one active-low and one active-high enable. This difference in enable polarity means the pin functions differ, preventing direct drop-in replacement without circuit modification.
What are the typical operating voltage and logic levels for these devices?
Both devices operate over a supply voltage range of 2.0 V to 6.0 V, with typical operation at 5.0 V. They are characterized for AC family CMOS logic levels, with high noise immunity and balanced propagation delays.
What is the output drive capability of the 74AC244SCX and 74AC241SC?
Both devices provide ±24 mA output drive at 5.0 V, making them suitable for driving bus lines and high-capacitive loads in high-speed digital systems.
What package types are available for the 74AC244SCX and 74AC241SC?
The 74AC244SCX is commonly offered in SOIC-20 and TSSOP-20 packages. The 74AC241SC is typically available in SOIC-20 and TSSOP-20 packages as well. Package options may vary by manufacturer; always verify with the specific manufacturer datasheet.
Can the 74AC244SCX and 74AC241SC be used interchangeably in an existing design?
No, they cannot be used interchangeably without design changes. The difference in output enable polarity (active-low vs. active-high) means the control logic must be adjusted. Additionally, pin functions differ, so the PCB layout and signal routing may require modification.
What are the typical propagation delay and operating temperature ranges for these devices?
Both devices feature typical propagation delays of approximately 5 ns at 5.0 V. The operating temperature range is typically -40°C to +85°C for industrial-grade versions, and -40°C to +125°C for automotive-grade versions where available. Verify exact specifications with the manufacturer datasheet.