Part A
74VHC595MX
Fairchild Semiconductor Inc
- Lifecycle
- Active
- Stock
- 3740 PCS
- Package
- SOIC-16
- Series
- Logique - Registre à décalage
Replacement verdict
Not a drop-in replacement
The 74VHC595MX and 74VHC08MX 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 74VHC08MX is a quad 2-input AND gate array. 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 pinout
Different output type
Different signal architecture
Parts at a glance
Part B
74VHC08MX
Semi - conducteurs
- Lifecycle
- Active
- Stock
- 2057 PCS
- Series
- Logique - portes et Onduleurs
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 | 74VHC08MX | Why it matters |
|---|---|---|---|
| Logic Function | 8-Bit Serial-In/Serial-Out or Parallel-Out Shift Register with Output Latches | Quad 2-Input AND Gate | The core logic function determines whether the devices are functionally interchangeable; these two parts perform completely different operations and cannot substitute for one another. |
| Number of Pins | 16 | 14 | Pin count affects PCB footprint and package compatibility; a 16-pin device cannot drop into a 14-pin footprint. |
| Package / Case | SOIC-16 (0.154", 3.90mm Width) | SOIC-14 (0.154", 3.90mm Width) | The physical package and body width must match the board layout for direct replacement; different pin counts yield different package outlines. |
| Output Type | Tri-State (3-State) with Serial and Parallel Outputs | Standard Push-Pull (Totem-Pole) | Output configuration determines how the device drives loads and whether outputs can be shared on a bus; tri-state outputs allow bus multiplexing while push-pull does not. |
| Number of Outputs | 9 (8 parallel + 1 serial) | 4 | The number of outputs dictates how many signals the device can drive, directly affecting circuit design and fan-out requirements. |
| Number of Inputs | 4 (SER, SRCLK, RCLK, OE, SRCLR) | 8 (two per gate) | Input count and configuration determine the control interface and logic capability of the device. |
| Propagation Delay (tpd) | ~10.2 ns (typical at 5V) | ~7.5 ns (typical at 5V) | Propagation delay affects maximum operating frequency and timing margins in synchronous designs. |
| Supply Voltage Range | 2.0V to 5.5V | 2.0V to 5.5V | The supply voltage range must be compatible with the system power rail; both parts share the same VHC family range, so this parameter is identical. |
| Maximum Operating Frequency | ~115 MHz (at 5V) | ~110 MHz (at 5V) | Maximum frequency determines the highest clock rate the device can reliably process in high-speed digital systems. |
| Logic Family | VHC (Very High-Speed CMOS) | VHC (Very High-Speed CMOS) | Logic family compatibility ensures consistent voltage thresholds, noise margins, and interfacing with other logic devices in the same family. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74VHC595MX | 74VHC08MX |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Part Status | Active | Active |
| Series | 74VHC | - |
| Logic Type | Shift Register | - |
| Output Type | Tri-State | - |
| Number of Elements | 1 | - |
| Number of Bits per Element | 8 | - |
| Function | Serial to Parallel, Serial | - |
| Voltage - Supply | 2V ~ 5.5V | - |
| Operating Temperature | -40°C ~ 85°C | - |
| Mounting Type | Surface Mount | - |
Frequently asked questions
What are the primary functions of the 74VHC595MX and 74VHC08MX?
The 74VHC595MX is an 8-bit serial-in, parallel-out shift register with output latches and 3-state outputs. The 74VHC08MX contains four independent 2-input AND gates.
Can the 74VHC595MX and 74VHC08MX be used interchangeably?
No. They perform fundamentally different logic functions: the 74VHC595MX is a shift register for serial-to-parallel data conversion, while the 74VHC08MX is a quad 2-input AND gate for combinational logic. They are not pin-compatible or functionally equivalent.
Do both devices operate from the same supply voltage range?
Yes. Both the 74VHC595MX and 74VHC08MX are VHC-family devices specified for a 2.0 V to 5.5 V supply voltage range, with typical operation at 3.3 V or 5 V.
What logic family and output drive characteristics do these parts share?
Both are 74VHC CMOS devices featuring balanced output drive, typically ±8 mA at 5 V, and are compatible with TTL input thresholds when operated at 5 V.
Are the 74VHC595MX and 74VHC08MX available in the same package type?
Both are commonly offered in SOIC-14 packages by manufacturers such as ON Semiconductor (onsemi). However, package options can vary by manufacturer and ordering code, so the specific datasheet must be consulted.
Which device is suitable for expanding microcontroller output pins?
The 74VHC595MX is suitable for output expansion because it converts a serial data stream into eight parallel outputs, requiring only three control lines. The 74VHC08MX is not intended for output expansion; it provides AND logic functions.
Do both devices have 3-state outputs?
No. The 74VHC595MX has 3-state parallel outputs controlled by an output enable pin. The 74VHC08MX has standard push-pull CMOS outputs and does not provide a high-impedance state.
What are the typical applications for each device?
The 74VHC595MX is typically used for LED drivers, relay control, and GPIO expansion. The 74VHC08MX is typically used for signal gating, enable/disable logic, and general-purpose AND logic functions.