Part A
74VHC595MX
Semiconductor Fairchild
- Lifecycle
- Active
- Stock
- 3740 PCS
- Package
- SOIC-16
- Series
- Lógica - Registos de Maiúsculas
Replacement verdict
Not a drop-in replacement
The 74VHC595MX and 74VHC02MX are not functionally interchangeable despite sharing the same VHC logic family and SOIC-16 package. The 74VHC595MX is an 8-bit serial-in/parallel-out shift register with tri-state output latches, while the 74VHC02MX is a quad 2-input NOR gate. Their internal logic functions, pin assignments, and signal flow architectures are fundamentally different, making direct substitution impossible without complete circuit redesign.
Different logic function
Different pin assignment
Different I/O architecture
Different application role
Parts at a glance
Part B
74VHC02MX
onsemi
- Lifecycle
- Active
- Stock
- 9 PCS
- Series
- Lógica - Gates e 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 | 74VHC595MX | 74VHC02MX | Why it matters |
|---|---|---|---|
| Logic Function | 8-Bit Serial-In/Serial-Out or Parallel-Out Shift Register with Output Latches | Quad 2-Input NOR Gate | The core logic function determines whether the devices are functionally interchangeable; these two parts perform entirely different operations and cannot substitute for one another. |
| Logic Family | VHC (Very High-Speed CMOS) | VHC (Very High-Speed CMOS) | Same logic family ensures compatible voltage thresholds, noise margins, and switching characteristics when interfacing with other VHC devices. |
| Number of Pins | 16 | 14 | Pin count affects PCB footprint and package compatibility; a 16-pin device cannot directly drop into a 14-pin socket. |
| Package Type | SOIC-16 | SOIC-14 | Different package outlines require different land patterns, so they are not mechanically interchangeable on the same PCB footprint. |
| Supply Voltage Range | 2.0 V to 5.5 V | 2.0 V to 5.5 V | Both support the same wide operating voltage, allowing use in 3.3 V and 5 V systems with identical power supply constraints. |
| Output Drive Current | ±8 mA | ±8 mA | Matching drive strength means both can drive similar loads, though the shift register's parallel outputs are typically used for driving LEDs or logic inputs. |
| Propagation Delay | Approximately 6 ns at 5 V | Approximately 5 ns at 5 V | Propagation delay affects maximum operating frequency and timing margins in synchronous designs. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Identical temperature ratings ensure both parts are suitable for the same industrial and commercial environments. |
| Input/Output Configuration | Serial input, serial/parallel outputs with latches | Two inputs per gate, one output per gate | The I/O structure defines how signals enter and exit the device, which is fundamental to circuit design and cannot be interchanged. |
| Mounting Type | Surface Mount | Surface Mount | Both are surface-mount devices, so they are compatible with the same assembly processes, though footprint differs. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74VHC595MX | 74VHC02MX |
|---|---|---|
| Supplier | - | onsemi |
| Series | 74VHC | 74VHC |
| Part Status | Active | Obsolete |
| Logic Type | Shift Register | NOR Gate |
| Number of Circuits | - | 4 |
| Number of Inputs | - | 2 |
| Voltage - Supply | 2V ~ 5.5V | 2V ~ 5.5V |
| Current - Quiescent (Max) | - | 2 µA |
| Current - Output High Low | - | 8mA, 8mA |
| Logic Level - Low | - | 0.5V |
| Logic Level - High | - | 1.5V |
| Max Propagation Delay @ V Max CL | - | 7.5ns @ 5V, 50pF |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
| Output Type | Tri-State | - |
| Number of Elements | 1 | - |
| Number of Bits per Element | 8 | - |
| Function | Serial to Parallel, Serial | - |
Frequently asked questions
What are the primary functional differences between the 74VHC595MX and the 74VHC02MX?
The 74VHC595MX is an 8-bit serial-in, parallel-out shift register with a storage register and 3-state outputs, while the 74VHC02MX is a quad 2-input NOR gate. They perform entirely different logic functions and are not interchangeable.
Do the 74VHC595MX and 74VHC02MX share the same package and pinout?
Both devices are typically offered in a 16-pin SOIC package (suffix MX), but their pinouts and internal functions differ. The 74VHC595MX uses pins for serial data, shift clock, storage clock, output enable, and eight parallel outputs, whereas the 74VHC02MX uses pins configured as four independent 2-input NOR gates.
Can the 74VHC595MX be used as a direct drop-in replacement for the 74VHC02MX?
No. The 74VHC595MX is a shift register and the 74VHC02MX is a logic gate array. Substituting one for the other would not provide the required logic function and would likely cause circuit malfunction.
What are the operating voltage and logic family specifications for both devices?
Both the 74VHC595MX and 74VHC02MX are part of the VHC (Very High Speed CMOS) family and typically operate over a supply voltage range of 2.0 V to 5.5 V, with balanced propagation delays and CMOS-compatible input thresholds.
Which device is suitable for serial-to-parallel data conversion?
The 74VHC595MX is the correct choice for serial-to-parallel data conversion because it contains an 8-bit shift register and an 8-bit storage register with parallel 3-state outputs. The 74VHC02MX cannot perform this function.
Which device is suitable for implementing a NOR logic function?
The 74VHC02MX is the correct choice for implementing NOR logic, as it contains four independent 2-input NOR gates. The 74VHC595MX does not provide logic gate functions.
Are the 74VHC595MX and 74VHC02MX interchangeable in terms of electrical characteristics?
No. Although both are VHC-family CMOS devices with similar supply voltage ranges and drive strengths, their input/output configurations, propagation delay paths, and functional pin assignments are different. They cannot be interchanged without redesigning the circuit.
What are the typical output drive capabilities of these devices?
Both the 74VHC595MX and 74VHC02MX typically provide ±8 mA output drive at 5 V, which is standard for VHC-family logic. However, the 74VHC595MX outputs are 3-state controlled, while the 74VHC02MX outputs are standard push-pull NOR gate outputs.