Part A
74HCT4051D
Toshiba Halbleiter und Speicher
- Lifecycle
- Active
- Stock
- 1430 Stückzahl
- Package
- SOP-16
- Series
- Schnittstelle für analoge Schalter, Multiplexer, Demultiplexer
Replacement verdict
Not a drop-in replacement
The 74HCT4051D and 74HCT02D,652 are functionally unrelated devices: one is an 8-channel analog multiplexer/demultiplexer, the other a quad 2-input NOR gate. They share only the 74HCT logic family and SO-16 package, so neither can substitute for the other in an existing design.
Different logic function
Different I/O architecture
Different signal path
Different pinout
Parts at a glance
Part B
74HCT02D,652
Nexperia USA Inc.
- Lifecycle
- Active
- Stock
- 3025 Stückzahl
- Series
- Logic-Gates und Wechselrichter
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74HCT4051D | 74HCT02D,652 | Why it matters |
|---|---|---|---|
| Function | Single 8-channel analog multiplexer/demultiplexer | Quad 2-input NOR gate | These devices perform completely different logic/analog functions, so they are not functionally interchangeable in a circuit. |
| Logic Family | HCT (high-speed CMOS, TTL-compatible) | HCT (high-speed CMOS, TTL-compatible) | Matching logic family ensures compatible input thresholds and output levels when interfacing with TTL logic. |
| Supply Voltage Range (VCC) | 4.5 V to 5.5 V | 4.5 V to 5.5 V | Both operate from a standard 5 V supply, so power rail compatibility is maintained. |
| Number of Channels / Gates | 1 multiplexer with 8 channels | 4 NOR gates | Channel/gate count determines how many signals can be routed or logic operations performed per package. |
| Package | SO16 (16-pin small outline) | SO14 (14-pin small outline) | Different pin counts and footprints prevent direct drop-in replacement on the same PCB pad layout. |
| Propagation Delay | Typically ~10 ns (at 5 V) | Typically ~9 ns (at 5 V) | Delay affects timing margins in high-speed digital paths; similar values ease timing analysis. |
| Output Drive Current | ±4 mA (standard CMOS output) | ±4 mA (standard CMOS output) | Drive strength determines fan-out and ability to drive loads or subsequent logic inputs. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Industrial temperature range ensures reliable operation in harsh environments. |
| Input Type | Analog/digital signal inputs with TTL-compatible control inputs | TTL-compatible digital inputs | Input compatibility affects whether the device can directly interface with TTL or analog signals. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HCT4051D | 74HCT02D,652 |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC,Nexperia USA Inc. |
| Series | - | 74HCT |
| Part Status | Active | Obsolete |
| Logic Type | - | NOR Gate |
| Number of Circuits | 1 | 4 |
| Number of Inputs | - | 2 |
| Voltage - Supply | - | 4.5V ~ 5.5V |
| Current - Quiescent (Max) | - | 2 µA |
| Current - Output High Low | - | 4mA, 4mA |
| Logic Level - Low | - | 0.8V |
| Logic Level - High | - | 2V |
| Max Propagation Delay @ V Max CL | - | 19ns @ 4.5V, 50pF |
| Operating Temperature | -40°C ~ 125°C (TA) | -40°C ~ 125°C |
| Mounting Type | Surface Mount | Surface Mount |
| Multiplexer / Demultiplexer Circuit | 8:1 | - |
| On - State Resistance(Max) | 120Ohm | - |
| Channel - to - Channel Matching(ΔRon) | 6Ohm | - |
| Voltage - Supply, Single (V+) | 4.5V ~ 5.5V | - |
| Voltage - Supply, Dual (V±) | ±1V ~ 5V | - |
| Switch Time(Ton Toff)(Max) | 39ns, 32ns | - |
| -3 dB Bandwidth | 180MHz | - |
| Channel Capacitance(CS(off)CD(off)) | 3.5pF | - |
| Current - Leakage(IS(off))(Max) | 400nA | - |
Frequently asked questions
What are the primary functional differences between the 74HCT4051D and the 74HCT02D,652?
The 74HCT4051D is an 8-channel analog multiplexer/demultiplexer with a single common input/output and eight independent channels, controlled by three digital select inputs. The 74HCT02D,652 is a quad 2-input NOR gate that performs a logic NOR function on four independent pairs of inputs. They serve entirely different signal-routing and logic functions and are not functionally interchangeable.
Are the 74HCT4051D and 74HCT02D,652 pin-compatible?
No. The 74HCT4051D is typically supplied in a 16-pin SOIC package, while the 74HCT02D,652 is supplied in a 14-pin SOIC package. The pin counts and pin functions differ, so they cannot be used as drop-in replacements for each other on the same PCB footprint.
Do both devices operate from the same supply voltage range?
Both are HCT-family logic devices and are specified for a nominal 5 V supply, typically with an operating range of 4.5 V to 5.5 V. However, the 74HCT4051D also supports analog signal switching within its specified analog voltage limits, which is not applicable to the 74HCT02D,652.
Can the 74HCT4051D be used to switch digital logic signals, and can the 74HCT02D,652 be used for analog signal routing?
The 74HCT4051D can pass both analog and digital signals within its specified signal voltage range, making it suitable for multiplexing digital logic lines. The 74HCT02D,652 is a digital logic gate intended for binary logic operations and is not designed or specified for analog signal routing.
What are the logic input threshold characteristics of these HCT devices?
HCT-family devices are designed with TTL-compatible input thresholds when operated at 5 V, allowing them to interface with TTL logic levels while retaining CMOS output characteristics. This applies to the digital control inputs of the 74HCT4051D and to the inputs of the 74HCT02D,652.
Which device is appropriate for selecting one of several signal sources?
The 74HCT4051D is the appropriate choice for selecting one of eight signal sources, since it is an 8-channel multiplexer/demultiplexer. The 74HCT02D,652 cannot perform signal selection; it only provides four independent 2-input NOR logic functions.
Are the 74HCT4051D and 74HCT02D,652 interchangeable in a logic circuit?
No. Because one is an analog multiplexer/demultiplexer and the other is a quad 2-input NOR gate, they have different functions, pin counts, and internal architectures. Substitution would require a complete redesign of the surrounding circuit and cannot be done directly.