Part A
74HC573D
東芝セミコンダクター・アンド・ストレージ
- Lifecycle
- Active
- Stock
- 3424 個数
- Package
- SOIC-14
- Series
- ロジック - ラッチ
Replacement verdict
Not a drop-in replacement
The 74HC573D and 74HC595D,112 are not functionally interchangeable despite sharing the same 74HC CMOS logic family and SO-16 package. The 74HC573D is an octal D-type transparent latch with 3-state outputs, while the 74HC595D,112 is an 8-bit serial-in/parallel-out shift register with output latches and 3-state outputs. Their internal architectures, pin functions, and control interfaces differ fundamentally, so direct substitution is not possible without redesigning the surrounding circuitry.
Different logic function
Different data interface
Different pin function
Different control signals
Parts at a glance
Part B
74HC595D,112
ネクスペリアUSA株式会社
- Lifecycle
- Active
- Stock
- 3930 個数
- Package
- SOIC-16
- Series
- ロジック - シフトレジスタ
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74HC573D | 74HC595D,112 | Why it matters |
|---|---|---|---|
| Logic Function | Octal D-type transparent latch with 3-state outputs | 8-bit serial-in, serial/parallel-out shift register with output latches | Defines the fundamental behavior; a latch captures parallel data while a shift register serializes data, so they are not functionally interchangeable. |
| Data Input Type | Parallel (8-bit) | Serial (with serial data input and shift clock) | Determines how data is loaded into the device, affecting the host interface and required control signals. |
| Output Type | 3-state parallel outputs | 3-state parallel outputs plus serial output (Q7') | The 74HC595 provides a serial cascade output for daisy-chaining, while the 74HC573 does not, impacting expandability. |
| Number of Outputs | 8 | 8 parallel + 1 serial | The extra serial output on the 74HC595 enables cascading multiple devices without additional host pins. |
| Latch/Register Control | Latch Enable (LE) and Output Enable (OE) | Shift Register Clock (SHCP), Storage Register Clock (STCP), Output Enable (OE), Shift Register Clear (MR) | Different control pin sets mean the driving logic and timing sequences are incompatible between the two parts. |
| Propagation Delay (typical at 5V) | ~13 ns (tPHL/tPLH) | ~14 ns (shift clock to output) | Affects maximum operating frequency and timing margins in high-speed designs. |
| Supply Voltage Range | 2 V to 6 V | 2 V to 6 V | Both support the same HC-family supply range, allowing use in 3.3 V and 5 V systems. |
| Output Drive Current | ±6 mA (at 5 V) | ±6 mA (at 5 V) | Determines the ability to drive LEDs, logic inputs, or other loads directly. |
| Package | SOIC-20 (D suffix) | SOIC-16 (D suffix) | Different pin counts and footprints prevent direct PCB drop-in replacement. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Both meet industrial temperature requirements, suitable for the same environmental conditions. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC573D | 74HC595D,112 |
|---|---|---|
| Supplier | - | Nexperia USA Inc. |
| Series | 74HC | 74HC |
| Part Status | Active | Obsolete |
| Logic Type | D-Type Latch | Shift Register |
| Output Type | Tri-State | Tri-State |
| Number of Elements | - | 1 |
| Number of Bits per Element | - | 8 |
| Function | - | Serial to Parallel, Serial |
| Voltage - Supply | 2V ~ 6V | 2V ~ 6V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 125°C |
| Mounting Type | Surface Mount | Surface Mount |
| Circuit | 8:8 | - |
| Independent Circuits | 1 | - |
| Delay Time - Propagation | 26ns | - |
| Current - Output High Low | 7.8mA, 7.8mA | - |
Frequently asked questions
What is the primary functional difference between the 74HC573D and the 74HC595D,112?
The 74HC573D is an octal D-type transparent latch with 3-state outputs, designed for temporary data storage and bus driving. The 74HC595D,112 is an 8-bit serial-in, parallel-out shift register with a storage register and 3-state outputs, designed for serial-to-parallel data conversion and driving loads such as LEDs.
Can the 74HC573D and 74HC595D,112 be used interchangeably in a design?
No. The 74HC573D requires parallel data inputs and a latch enable signal, while the 74HC595D,112 accepts serial data and a shift clock. Their pin functions, control logic, and data flow are fundamentally different, so they are not pin-compatible or functionally interchangeable.
What are the output drive capabilities of the 74HC573D and 74HC595D,112?
Both devices are 74HC-family CMOS ICs and typically provide standard CMOS output drive, which is generally sufficient for driving low-power loads and logic inputs. For specific output current ratings, refer to the manufacturer datasheet, as absolute maximum ratings and recommended operating conditions must be observed.
Do the 74HC573D and 74HC595D,112 operate at the same supply voltage range?
Yes. Both are 74HC-series devices and typically operate over a supply voltage range of 2.0 V to 6.0 V. However, always verify the exact recommended operating conditions in the respective manufacturer datasheet for the specific part number and package.
What package type is the 74HC573D and the 74HC595D,112?
The suffix "D" in 74HC573D typically indicates a SOIC package, while the 74HC595D,112 suffix also indicates a SOIC package with a specific packing or ordering variant. Package dimensions and pin counts should be confirmed from the manufacturer datasheet before PCB layout.
Which device is better for expanding microcontroller I/O with minimal pins?
The 74HC595D,112 is generally preferred for I/O expansion because it requires only three control lines (serial data, shift clock, and latch clock) to control eight outputs. The 74HC573D requires eight parallel data lines plus control signals, consuming more microcontroller pins.
Are the 74HC573D and 74HC595D,112 3-state output devices?
Yes. Both devices feature 3-state outputs, allowing their outputs to be placed in a high-impedance state for bus sharing or disabling connected loads. The output enable control is provided on both devices, though the control pin names and logic may differ.
What is the function of the latch enable on the 74HC573D compared to the latch clock on the 74HC595D,112?
On the 74HC573D, the latch enable (LE) pin controls whether the outputs follow the inputs (transparent mode) or hold the last data (latched mode). On the 74HC595D,112, the latch clock (RCLK) transfers data from the internal shift register to the output storage register on a rising edge, enabling simultaneous output updates.