Part A
74ACT125SCX
onsemi
- Lifecycle
- Active
- Stock
- 6699 PCS
- Package
- SOIC-14
- Series
- Logic - Buffers, Drivers, Receivers, Transceivers
Replacement verdict
Compatible functional replacement candidate
The 74ACT125SCX and 74ACT125SJX are functionally equivalent quad bus buffer gates with 3-state outputs from the same 74ACT logic family, differing only in package type. Both devices share identical logic function, electrical characteristics, and operating temperature range, making the 74ACT125SJX a viable functional replacement for the 74ACT125SCX provided the board layout accommodates the different package footprint.
Logic Function
High match
Output Type
High match
Package Type
Not compatible
Operating Temperature
High match
Parts at a glance
Part B
74ACT125SJX
onsemi
- Lifecycle
- Active
- Stock
- 8214 PCS
- Package
- SOIC-14
- Series
- Logic - Buffers, Drivers, Receivers, Transceivers
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74ACT125SCX | 74ACT125SJX | Why it matters |
|---|---|---|---|
| Manufacturer | onsemi | onsemi | Same manufacturer ensures consistent process, quality, and documentation for both parts. |
| Logic Family | ACT | ACT | Same logic family guarantees identical input/output thresholds and speed characteristics. |
| Function | Quad Buffer with 3-State Outputs | Quad Buffer with 3-State Outputs | Identical logic function is required for direct functional substitution. |
| Number of Channels | 4 | 4 | Channel count must match to preserve circuit topology and signal routing. |
| Supply Voltage Range | 4.5 V to 5.5 V | 4.5 V to 5.5 V | Compatible supply range ensures the part operates correctly in the target system. |
| Output Type | 3-State | 3-State | 3-state outputs allow bus sharing and must match for equivalent system behavior. |
| Package / Case | SOIC-14 | SOP-14 | Different package footprints affect PCB layout and may require board redesign. |
| Mounting Type | Surface Mount | Surface Mount | Mounting style must match the assembly process and board design. |
| Packaging | Tape & Reel | Tape & Reel | Packaging affects handling and automated assembly compatibility. |
| Operating Temperature Range | -40°C to 85°C | -40°C to 85°C | Matching temperature range ensures reliability across the intended application environment. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74ACT125SCX | 74ACT125SJX |
|---|---|---|
| Supplier | - | onsemi |
| Series | 74ACT | 74ACT |
| Part Status | Obsolete | Obsolete |
| Logic Type | Buffer, Non-Inverting | Buffer, Non-Inverting |
| Number of Elements | 4 | 4 |
| Number of Bits per Element | 1 | 1 |
| Output Type | 3-State | 3-State |
| Current - Output High Low | 24mA, 24mA | 24mA, 24mA |
| Voltage - Supply | 4.5V ~ 5.5V | 4.5V ~ 5.5V |
| Operating Temperature | -40°C ~ 85°C (TA) | -40°C ~ 85°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the 74ACT125SCX and 74ACT125SJX?
Both are quad bus buffer gates with 3-state outputs from the 74ACT logic family. The 74ACT125SCX is supplied in a 14-lead SOIC package, while the 74ACT125SJX is supplied in a 14-lead SOP (also referred to as SOIC) package. Both devices feature four independent non-inverting buffers with active-low output enable pins.
What is the difference between the 74ACT125SCX and 74ACT125SJX?
The primary difference is the package type and corresponding part number suffix. The 74ACT125SCX uses the SC suffix, which denotes a 14-lead SOIC package with a narrow body width of 3.9 mm. The 74ACT125SJX uses the SJ suffix, which denotes a 14-lead SOP package with a body width of 5.3 mm. Electrical specifications and logic function are identical between the two devices.
Are the 74ACT125SCX and 74ACT125SJX electrically interchangeable?
Yes. Both devices share the same ACT logic family characteristics, including TTL-compatible input thresholds, 5 V nominal supply voltage, and 3-state output drive. They can be used interchangeably in circuits where the PCB footprint accommodates the respective package dimensions.
Can the 74ACT125SCX and 74ACT125SJX be used as direct drop-in replacements for each other?
No, not as direct drop-in replacements without PCB modification. Although the electrical function is identical, the SOIC (SC suffix) and SOP (SJ suffix) packages have different body widths and lead spans. The 74ACT125SCX has a 3.9 mm body width, while the 74ACT125SJX has a 5.3 mm body width. The PCB land patterns are not identical, so a board designed for one package may not accept the other without layout changes.
What is the operating voltage range for the 74ACT125SCX and 74ACT125SJX?
Both devices operate over a recommended supply voltage range of 4.5 V to 5.5 V, with 5 V as the nominal supply. This is consistent with the standard 74ACT logic family specifications.
What is the output drive capability of the 74ACT125SCX and 74ACT125SJX?
Both devices provide ±24 mA output drive at 5 V, which is typical for the 74ACT125 function. This allows them to drive moderate capacitive loads and interface with other logic families in mixed-voltage systems.
What is the function of the output enable pins on the 74ACT125SCX and 74ACT125SJX?
Each of the four buffers has an independent active-low output enable (OE) pin. When OE is low, the corresponding buffer output is active and follows the input. When OE is high, the output enters a high-impedance state, allowing the bus to be shared with other drivers.
Are the 74ACT125SCX and 74ACT125SJX RoHS compliant?
RoHS compliance depends on the specific manufacturer and date code. Many manufacturers offer RoHS-compliant versions of these part numbers, often indicated by a suffix or a separate ordering code. Designers should verify the compliance status on the manufacturer's datasheet or the distributor's product page for the exact orderable part number.