Part A
74HC125D
Toshiba Semiconductor and Storage
- Lifecycle
- Active
- Stock
- 3803 PCS
- Package
- SOIC-14
- Series
- Logic - Buffers, Drivers, Receivers, Transceivers
Replacement verdict
Not a drop-in replacement
The 74HC125D and 74HC154D,652 are functionally unrelated devices and cannot serve as substitutes for one another. The 74HC125D is a quad bus buffer with 3-state outputs, while the 74HC154D,652 is a 4-to-16 line decoder/demultiplexer. Their logic functions, pin configurations, and output characteristics differ fundamentally, making direct replacement impossible without complete circuit redesign.
Different logic function
Different output type
Different pin count
Different package footprint
Parts at a glance
Part B
74HC154D,652
NXP USA Inc.
- Lifecycle
- Active
- Stock
- 2528 PCS
- Package
- SOIC-24
- Series
- Logic - Signal Switches, Multiplexers, Decoders
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74HC125D | 74HC154D,652 | Why it matters |
|---|---|---|---|
| Function | Quad buffer/line driver with 3-state outputs | 4-to-16 line decoder/demultiplexer | The core logic function differs, so these parts are not functionally interchangeable in a circuit. |
| Number of Channels / Outputs | 4 independent buffers | 16 mutually exclusive outputs | Channel count determines how many signals can be handled and how the device maps to system I/O. |
| Output Type | 3-state (tri-state) outputs | Active-low outputs (non-tri-state) | Tri-state outputs allow bus sharing, while the decoder's outputs are intended for direct selection lines. |
| Control Inputs | Output enable (OE) per buffer | 4 address inputs plus 2 enable inputs | Different control schemes affect how the device is driven and integrated into a design. |
| Logic Family | HC (High-speed CMOS) | HC (High-speed CMOS) | Same logic family means compatible voltage levels and similar speed/power characteristics. |
| Supply Voltage Range | 2 V to 6 V | 2 V to 6 V | Matching supply ranges allow both parts to operate in the same system voltage environment. |
| Propagation Delay (typical) | Approximately 10 ns at 5 V | Approximately 20 ns at 5 V | Timing differences can affect signal integrity and maximum operating frequency in synchronous designs. |
| Package | SO14 (SOIC-14) | SO24 (SOIC-24) | Different package sizes and pin counts require different PCB footprints and cannot be dropped in interchangeably. |
| Pin Count | 14 pins | 24 pins | Pin count mismatch prevents direct physical replacement and affects board layout. |
| Typical Application | Bus buffering, signal gating, level driving | Memory/address decoding, peripheral selection | Intended use cases differ, so substitution would require significant redesign rather than simple replacement. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC125D | 74HC154D,652 |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | 74HC | 74HC |
| Part Status | Active | Active |
| Type | - | Decoder/Demultiplexer |
| Circuit | - | 1 x 4:16 |
| Independent Circuits | - | 1 |
| Current - Output High Low | 7.8mA, 7.8mA | 5.2mA, 5.2mA |
| Voltage Supply Source | - | Single Supply |
| Voltage - Supply | 2V ~ 6V | 2V ~ 6V |
| Operating Temperature | -40°C ~ 125°C (TA) | -40°C ~ 125°C |
| Mounting Type | Surface Mount | Surface Mount |
| Logic Type | Buffer, Non-Inverting | - |
| Number of Elements | 4 | - |
| Number of Bits per Element | 1 | - |
| Output Type | 3-State | - |
Frequently asked questions
What are the primary functional differences between the 74HC125D and the 74HC154D,652?
The 74HC125D is a quad non-inverting buffer/line driver with 3-state outputs, while the 74HC154D,652 is a 4-to-16 line decoder/demultiplexer. The 74HC125D provides four independent buffer channels with active-LOW output enable pins, whereas the 74HC154D,652 decodes a 4-bit binary address into one of sixteen mutually exclusive active-LOW outputs.
Are the 74HC125D and 74HC154D,652 pin-compatible?
No. The 74HC125D is typically supplied in a 14-pin SOIC package, while the 74HC154D,652 is supplied in a 24-pin SOIC package. They have different pin counts, pin assignments, and functions, so they are not pin-compatible or interchangeable.
Can the 74HC125D be used as a drop-in replacement for the 74HC154D,652 in a decoder application?
No. The 74HC125D cannot perform 4-to-16 decoding. It contains four independent 3-state buffers and lacks the address decoding logic and sixteen outputs required to replace the 74HC154D,652 in a decoder/demultiplexer application.
What are the supply voltage and logic family specifications for both devices?
Both the 74HC125D and the 74HC154D,652 are members of the 74HC high-speed CMOS logic family and are specified for a nominal supply voltage range of 2.0 V to 6.0 V, with 5.0 V being the most common operating condition. They are not 74HCT variants, so they do not have TTL-compatible input thresholds.
How do the output drive capabilities of the 74HC125D and 74HC154D,652 compare?
Both devices are standard 74HC CMOS outputs. The 74HC125D is specified with a standard 74HC output drive of ±4 mA at 5 V, and the 74HC154D,652 is also specified with standard 74HC output drive of ±4 mA at 5 V. Neither device is a high-drive bus-interface version.
What is the difference in propagation delay between the 74HC125D and the 74HC154D,652?
At 5 V, the 74HC125D typically exhibits a propagation delay of approximately 10 ns to 15 ns from input to output. The 74HC154D,652 typically exhibits a propagation delay of approximately 20 ns to 30 ns from address input to output, reflecting the additional decoding logic stages. Exact limits should be verified from the respective manufacturer datasheets.
Which device is better suited for expanding microcontroller I/O, and which is better for address decoding?
The 74HC125D is better suited for buffering, isolating, or expanding microcontroller I/O lines because it provides four independent 3-state non-inverting buffers. The 74HC154D,652 is better suited for address decoding or demultiplexing because it converts a 4-bit binary input into one of sixteen active-LOW outputs, making it appropriate for memory or peripheral chip-select generation.
Do the 74HC125D and 74HC154D,652 have the same operating temperature range?
Both devices are typically specified for the standard industrial temperature range of -40 °C to +125 °C or -40 °C to +85 °C depending on the specific manufacturer and orderable part number. The exact temperature grade should be confirmed from the manufacturer datasheet for the specific device marking and package option.