Part A
74HC4538D
Toshiba Semiconductor và lưu trữ
- Lifecycle
- Active
- Stock
- 1231 PCS
- Package
- SOIC-16
- Series
- Logic - Multivibrators
Replacement verdict
Not a drop-in replacement
The 74HC4538D and 74HC4015DB,112 are functionally unrelated ICs and cannot be used as substitutes for one another. The 74HC4538D is a dual retriggerable monostable multivibrator with timing and pulse-generation functions, while the 74HC4015DB,112 is a dual 4-bit static shift register for serial-to-parallel data conversion. Their internal architectures, pin functions, and application roles differ fundamentally, so direct replacement is not feasible without complete circuit redesign.
Different logic function
Different pin function
Different package type
Different application role
Parts at a glance
Part B
74HC4015DB,112
NXP Hoa Kỳ Inc.
- Lifecycle
- Active
- Stock
- 9038 PCS
- Package
- SSOP-16
- Series
- Logic - Shift Registers
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74HC4538D | 74HC4015DB,112 | Why it matters |
|---|---|---|---|
| Function | Dual retriggerable monostable multivibrator | Dual 4-bit static shift register | These devices perform fundamentally different logic functions, so they are not functionally substitutable in a circuit. |
| Logic Type | Monostable multivibrator | Shift register | The logic type determines the device's role in timing versus data storage/transfer applications. |
| Number of Circuits | 2 | 2 | Both integrate two independent elements per package, but each element performs a different function. |
| Number of Bits per Element | Not applicable (monostable timing element) | 4 | Bit width defines the storage capacity of the shift register and is not applicable to a monostable multivibrator. |
| Output Type | Complementary (Q and Qbar) | Push-pull | Output configuration affects how the device interfaces with downstream logic and whether inverted signals are available. |
| Supply Voltage Range | 2 V to 6 V | 2 V to 6 V | Both operate over the standard HC-family supply range, allowing use in similar logic-level systems. |
| Propagation Delay | Typically ~25 ns at 4.5 V | Typically ~15 ns at 4.5 V | Propagation delay influences maximum operating frequency and timing margins in synchronous designs. |
| Package / Mounting Type | SOIC-16, surface mount | SSOP-16, surface mount | Package footprint and mounting style must match the PCB layout for physical compatibility. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Both support industrial temperature ranges, making them suitable for similar environmental conditions. |
| Trigger / Input Type | Edge-triggered (rising/falling) | Serial data, clock, and reset inputs | Input signaling requirements differ completely, preventing direct pin-to-pin substitution. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC4538D | 74HC4015DB,112 |
|---|---|---|
| Supplier | - | NXP USA Inc. |
| Series | 74HC | 74HC |
| Part Status | Active | Obsolete |
| Logic Type | Monostable | Shift Register |
| Output Type | - | Push-Pull |
| Number of Elements | - | 2 |
| Number of Bits per Element | - | 4 |
| Function | - | Serial to Parallel |
| Voltage - Supply | 2 V ~ 6 V | 2V ~ 6V |
| Operating Temperature | -40°C ~ 125°C (TA) | -40°C ~ 125°C |
| Mounting Type | Surface Mount | Surface Mount |
| Independent Circuits | 2 | - |
| Schmitt Trigger Input | Yes | - |
| Propagation Delay | 25 ns | - |
| Current - Output High Low | 5.2mA, 5.2mA | - |
Frequently asked questions
What are the primary functional differences between the 74HC4538D and the 74HC4015DB,112?
The 74HC4538D is a dual retriggerable/resettable monostable multivibrator (one-shot) that generates a precise output pulse width determined by an external resistor and capacitor. The 74HC4015DB,112 is a dual 4-bit static shift register that stores and shifts serial data in parallel or serial form. They serve fundamentally different logic functions and are not interchangeable.
Can the 74HC4538D be used as a direct substitute for the 74HC4015DB,112 in an existing design?
No. The 74HC4538D is a monostable multivibrator for pulse generation, while the 74HC4015DB,112 is a dual 4-bit shift register for data storage and serial-to-parallel conversion. Their pinouts, internal logic, and external component requirements differ, so a direct substitution is not possible without redesigning the circuit.
What are the package and pin count differences between the 74HC4538D and the 74HC4015DB,112?
The 74HC4538D is typically supplied in a 16-pin SOIC package. The 74HC4015DB,112 is supplied in a 16-pin SSOP (DB) package. Both have 16 pins, but the pin functions and PCB land patterns differ, so they are not footprint-compatible despite similar pin counts.
Do the 74HC4538D and 74HC4015DB,112 operate at the same supply voltage and logic levels?
Yes. Both are 74HC-series CMOS devices and operate over a standard supply voltage range of 2.0 V to 6.0 V, with typical 5 V operation. They also share standard CMOS input and output logic levels, making them compatible with other 74HC-series logic in the same system.
Which device is better suited for pulse-width generation or timing applications?
The 74HC4538D is the correct choice for pulse-width generation or timing applications. It provides two independent monostable multivibrators with retriggerable and resettable capability, and the output pulse width is set by an external resistor and capacitor. The 74HC4015DB,112 does not provide timing or one-shot functions.
Which device is better suited for serial-to-parallel data conversion or data storage?
The 74HC4015DB,112 is the correct choice for serial-to-parallel data conversion or temporary data storage. It contains two independent 4-bit static shift registers with serial and parallel inputs and serial and parallel outputs. The 74HC4538D cannot perform shift register or data storage functions.
Are the 74HC4538D and 74HC4015DB,112 interchangeable in terms of external component requirements?
No. The 74HC4538D requires external timing components (a resistor and capacitor per monostable section) to set the output pulse width. The 74HC4015DB,112 requires no external timing components for its shift register operation. This difference prevents any direct interchangeability.
Do both devices support the same operating temperature range?
Both the 74HC4538D and the 74HC4015DB,112 are specified for the standard industrial temperature range of -40 °C to +125 °C, as is typical for 74HC-series logic devices. Always confirm the exact temperature grade from the specific manufacturer datasheet before use in extreme environments.