Part A
74HCT4051D
Toshiba Semiconductor and Storage
- Lifecycle
- Active
- Stock
- 1430 PCS
- Package
- SOP-16
- Series
- Interface - Analog Switches, Multiplexers, Demultiplexers
Replacement verdict
Not a drop-in replacement
The 74HCT4051D and 74HCT08D,652 are functionally unrelated devices: one is an 8-channel analog multiplexer/demultiplexer and the other is a quad 2-input AND gate. They share only the 74HCT logic family and SO-16 package, but their internal signal paths, logic functions, and pin assignments are fundamentally different, so neither part can substitute for the other in an existing design.
Different logic function
Different signal path type
Different pin assignment
Different input/output structure
Parts at a glance
Part B
74HCT08D,652
NXP Semiconductors
- Lifecycle
- Active
- Stock
- 7336 PCS
- Series
- Logic - Gates and Inverters
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 | 74HCT08D,652 | Why it matters |
|---|---|---|---|
| Function | Single 8-channel analog multiplexer/demultiplexer | Quad 2-input AND gate | These devices perform completely different logic/analog switching functions, so they are not functionally interchangeable in a circuit. |
| Logic Family | HCT (high-speed CMOS, TTL-compatible) | HCT (high-speed CMOS, TTL-compatible) | Both belong to the same HCT family, so they share compatible input thresholds and supply voltage ranges. |
| Supply Voltage Range (VCC) | 4.5 V to 5.5 V | 4.5 V to 5.5 V | Identical operating voltage range allows both to be used in standard 5 V TTL-compatible systems. |
| Number of Channels / Gates | 1 channel (8:1 multiplexer) | 4 gates (2-input AND) | Channel/gate count determines how many signals can be routed or combined, directly affecting circuit architecture. |
| Propagation Delay (tpd) | Typically ~10 ns at 5 V | Typically ~10 ns at 5 V | Similar propagation delays mean comparable timing performance in high-speed digital designs. |
| Output Drive Current (IOH/IOL) | ±4 mA (standard HCT output) | ±4 mA (standard HCT output) | Matching drive strength ensures both can drive similar loads without additional buffering. |
| Package Type | SO16 (SOIC-16) | SO14 (SOIC-14) | Different pin counts and footprints prevent direct PCB drop-in replacement without layout changes. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Identical temperature ratings make both suitable for industrial and automotive-grade environments. |
| Input Type | Analog/digital signal inputs (bidirectional) | Digital logic inputs (TTL-compatible) | The multiplexer handles analog signals while the AND gate only processes digital logic, limiting substitutability. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HCT4051D | 74HCT08D,652 |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Part Status | Active | Active |
| Multiplexer / Demultiplexer Circuit | 8:1 | - |
| Number of Circuits | 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 | - |
| Operating Temperature | -40°C ~ 125°C (TA) | - |
| Mounting Type | Surface Mount | - |
Frequently asked questions
What are the primary functional differences between the 74HCT4051D and the 74HCT08D,652?
The 74HCT4051D is an 8-channel analog multiplexer/demultiplexer that routes one of eight analog or digital signals to a common output, or vice versa. The 74HCT08D,652 contains four independent 2-input AND gates that perform digital logic operations. They serve fundamentally different roles: signal routing versus logic gating.
Are the 74HCT4051D and 74HCT08D,652 pin-compatible?
No. The 74HCT4051D is typically supplied in a 16-pin SOIC package, while the 74HCT08D,652 is supplied in a 14-pin SOIC package. They have different pin counts and pin assignments, so they cannot be used interchangeably on the same PCB footprint.
Can the 74HCT4051D and 74HCT08D,652 operate from the same supply voltage?
Yes. Both devices are members of the 74HCT logic family and are specified for a nominal supply voltage of 5 V, with a typical operating range of 4.5 V to 5.5 V. This allows them to be used in the same 5 V system.
Does the 74HCT4051D provide analog signal switching, and does the 74HCT08D,652 provide the same capability?
No. The 74HCT4051D is designed to pass analog signals within its specified voltage range and features low on-resistance and low off-state leakage, making it suitable for analog multiplexing. The 74HCT08D,652 is a digital logic device and is not intended for analog signal routing.
What are the logic input threshold characteristics of the 74HCT4051D and 74HCT08D,652?
Both devices are HCT-type, meaning they have TTL-compatible input thresholds when operated at 5 V. This allows them to interface directly with TTL logic levels while maintaining CMOS output characteristics.
Which device is suitable for multiplexing multiple sensor signals onto a single ADC input?
The 74HCT4051D is the appropriate choice because it is an 8-channel analog multiplexer designed to selectively connect one of eight analog inputs to a common output. The 74HCT08D,652 cannot perform this function because it is a digital AND gate array.
Do both the 74HCT4051D and 74HCT08D,652 have standard SOIC package options?
Yes. The 74HCT4051D is offered in a 16-pin SOIC package, and the 74HCT08D,652 is offered in a 14-pin SOIC package. Both are surface-mount packages, but their different pin counts and body widths must be considered during PCB layout.