Part A
74HC238D
東芝セミコンダクター・アンド・ストレージ
- Lifecycle
- Active
- Stock
- 5394 個数
- Package
- SOIC-16
- Series
- ロジック - 信号スイッチ、マルチプレクサ、デコーダ
Replacement verdict
Not a drop-in replacement
The 74HC238D and 74HC241D,652 are functionally unrelated logic ICs and cannot serve as substitutes for one another. The 74HC238D is a 3-to-8 line decoder/demultiplexer, while the 74HC241D,652 is an octal non-inverting buffer/line driver with 3-state outputs. Their differing logic functions, output configurations, pin assignments, and package types make direct replacement impossible without circuit redesign.
Different logic function
Different output type
Different pinout
Different package
Parts at a glance
Part B
74HC241D,652
パナソニック電子部品
- Lifecycle
- Active
- Stock
- 2734 個数
- Package
- SOIC-20
- Series
- ロジック - バッファ、ドライバ、レシーバ、トランシーバ
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74HC238D | 74HC241D,652 | Why it matters |
|---|---|---|---|
| Logic Function | 3-to-8 Line Decoder/Demultiplexer | Octal Buffer/Line Driver with 3-State Outputs | The core function determines whether the device can be substituted at all; a decoder and a buffer perform fundamentally different logic operations. |
| Number of Outputs | 8 | 8 | Both provide eight outputs, but the output behavior differs (decoded selection vs. buffered data passthrough). |
| Output Type | Active LOW (non-inverting decode) | 3-State, non-inverting | Output type affects bus interfacing; 3-state outputs allow bus sharing, while the decoder's active-LOW outputs are intended for direct selection lines. |
| Number of Inputs | 3 address inputs plus 2 enable inputs | 8 data inputs plus 2 output-enable inputs | Input count and function dictate the control scheme and pinout compatibility for a given application. |
| Propagation Delay (typical) | ~14 ns at 5 V | ~12 ns at 5 V | Timing differences can affect setup/hold margins in high-speed digital systems. |
| Supply Voltage Range | 2 V to 6 V | 2 V to 6 V | Both are HC-family compatible, so supply voltage is not a differentiator, but it confirms logic-level compatibility. |
| Output Drive Current | ±4 mA at 5 V | ±6 mA at 5 V | Drive strength affects fan-out and the ability to drive LEDs, transmission lines, or other loads directly. |
| Package | SO16 (SOIC-16) | SO20 (SOIC-20) | Different package sizes and pin counts prevent direct drop-in replacement on the same PCB footprint. |
| Pin Count | 16 | 20 | Pin count mismatch means the devices are not pin-to-pin compatible and require different board layouts. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Both meet industrial temperature requirements, so thermal compatibility is not a limiting factor for substitution. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC238D | 74HC241D,652 |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | 74HC | 74HC |
| Part Status | Active | Active |
| Logic Type | - | Buffer, Non-Inverting |
| Number of Elements | - | 2 |
| Number of Bits per Element | - | 4 |
| Output Type | - | 3-State |
| Current - Output High Low | 5.2mA, 5.2mA | 7.8mA, 7.8mA |
| Voltage - Supply | 2V ~ 6V | 2V ~ 6V |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 125°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
| Type | Decoder/Demultiplexer | - |
| Circuit | 1 x 3:8 | - |
| Independent Circuits | 1 | - |
| Voltage Supply Source | Single Supply | - |
Frequently asked questions
What are the primary functional differences between the 74HC238D and the 74HC241D,652?
The 74HC238D is a 3-to-8 line decoder/demultiplexer that routes one input to one of eight outputs based on a 3-bit address, while the 74HC241D,652 is an octal non-inverting buffer/line driver with 3-state outputs designed for bus-oriented data transmission.
Can the 74HC238D and 74HC241D,652 be used interchangeably in a circuit design?
No. They perform fundamentally different logic functions. The 74HC238D decodes binary addresses to activate one of eight mutually exclusive outputs, whereas the 74HC241D,652 buffers eight independent data lines with high-impedance output capability. Substitution would require complete redesign of the surrounding circuitry.
What are the package and pin count specifications for these devices?
Both the 74HC238D and 74HC241D,652 are supplied in SO16 (Small Outline, 16-pin) packages. The 74HC238D uses the standard SO16 footprint, and the 74HC241D,652 also uses a 16-pin SO package, though pin assignments and functions differ between the two types.
What supply voltage range do the 74HC238D and 74HC241D,652 support?
Both devices are members of the 74HC high-speed CMOS family and operate over a recommended supply voltage range of 2.0 V to 6.0 V, with typical operation at 5.0 V for standard logic-level interfacing.
Does the 74HC241D,652 have 3-state outputs, and does the 74HC238D share this feature?
Yes, the 74HC241D,652 features 3-state outputs controlled by two active-low output enable pins (1OE and 2OE), allowing each 4-bit group to be placed in high-impedance mode. The 74HC238D does not have 3-state outputs; its eight outputs are either HIGH or LOW based on the address inputs and enable conditions.
How do the output drive capabilities compare between the 74HC238D and 74HC241D,652?
Both devices are specified with standard 74HC CMOS output drive, typically capable of sourcing or sinking 4 mA at 5 V supply. The 74HC241D,652 is characterized for bus-driving applications, but neither device provides high-current drive beyond standard HC-family limits.
What are the enable and control input differences between the two parts?
The 74HC238D has three enable inputs (two active-low and one active-high) that must all be valid to activate the selected output. The 74HC241D,652 has two active-low output enable pins, each controlling four of the eight buffer channels independently.
Are the 74HC238D and 74HC241D,652 compatible with TTL logic levels?
Yes. Both devices are 74HC-family CMOS parts that accept standard TTL-compatible input thresholds when operated at 5 V, making them suitable for interfacing with TTL logic in mixed-technology systems.