Part A
74HC153D
Toshiba Semiconductor and Storage
- Lifecycle
- Active
- Stock
- 5590 PCS
- Package
- SOIC-20
- Series
- Logic - Signal Switches, Multiplexers, Decoders
Replacement verdict
Not a drop-in replacement
The 74HC153D and 74HC166D are functionally distinct logic ICs that cannot serve as substitutes for one another. The 74HC153D is a dual 4-to-1 multiplexer, while the 74HC166D is an 8-bit parallel-in/serial-out shift register. Their internal architectures, pin functions, and signal flow directions differ fundamentally, making direct replacement impossible without complete circuit redesign.
Different logic function
Different pin function
Different signal flow
Different input/output configuration
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74HC153D | 74HC166D | Why it matters |
|---|---|---|---|
| Logic Function | Dual 4-input multiplexer | 8-bit parallel-in/serial-out shift register | The core function determines whether the device selects between data inputs or shifts/stores data, so these parts are not functionally interchangeable. |
| Number of Select/Control Inputs | 2 select inputs (one per multiplexer) | 2 control inputs (shift/load and clock inhibit) | Control pin count and function affect how the device is driven in a circuit and whether it can directly replace another logic block. |
| Data Inputs | 8 data inputs (two groups of 4) | 9 data inputs (8 parallel plus serial) | The number and type of data inputs determine the device's role in routing versus serial data handling. |
| Data Outputs | 2 outputs (one per multiplexer) | 1 serial output | Output configuration affects signal fan-out and whether the part can drive parallel or serial data paths. |
| Output Type | Push-pull complementary outputs | Push-pull serial output | Output drive style influences compatibility with bus lines, pull-up/pull-down networks, and downstream logic. |
| Operating Mode | Combinational selection | Synchronous shift and parallel load | Combinational versus sequential operation changes timing behavior and the need for a clock signal. |
| Clock Requirement | No clock required | Requires clock for shifting and loading | Clock dependency affects circuit timing, synchronization, and whether the device can be used in purely combinational designs. |
| Typical Propagation Delay | Approximately 14 ns at 4.5 V | Approximately 15 ns at 4.5 V | Propagation delay impacts maximum operating speed and timing margins in high-frequency designs. |
| Supply Voltage Range | 2 V to 6 V | 2 V to 6 V | The supply range determines compatibility with 3.3 V and 5 V logic systems and ensures safe operation. |
| Package | SO14 | SO16 | Package and pin count affect PCB footprint, routing, and mechanical interchangeability. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC153D | 74HC166D |
|---|---|---|
| Supplier | - | Toshiba Semiconductor and Storage |
| Series | 74HC | 74HC |
| Part Status | Active | Active |
| Logic Type | - | Shift Register |
| Output Type | - | Push-Pull |
| Number of Elements | - | 1 |
| Number of Bits per Element | - | 8 |
| Function | - | Parallel or Serial to Serial |
| Voltage - Supply | 2V ~ 6V | 2V ~ 6V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 125°C |
| Mounting Type | Surface Mount | Surface Mount |
| Type | Multiplexer | - |
| Circuit | 2 x 4:1 | - |
| Independent Circuits | 2 | - |
| Current - Output High Low | 5.2mA, 5.2mA | - |
| Voltage Supply Source | Single Supply | - |
Frequently asked questions
What are the primary functions of the 74HC153D and 74HC166D?
The 74HC153D is a dual 4-input multiplexer that selects one of four data inputs per section based on two select inputs and provides complementary outputs. The 74HC166D is an 8-bit parallel-in/serial-out shift register that can load data in parallel or shift data serially.
Can the 74HC153D and 74HC166D be used interchangeably in a design?
No. They perform fundamentally different logic functions: the 74HC153D is a multiplexer, while the 74HC166D is a shift register. They are not pin-compatible or functionally equivalent, so direct substitution is not possible.
What are the package and pin count differences between the 74HC153D and 74HC166D?
Both devices are typically offered in a 16-pin SOIC package (the "D" suffix in NXP/Philips naming denotes SOIC). However, their pin assignments differ because of their different internal functions. The 74HC153D uses pins for two 4-input multiplexer sections, while the 74HC166D uses pins for parallel inputs, serial input, clock, and control signals.
Do the 74HC153D and 74HC166D operate at the same supply voltage and logic levels?
Yes. Both are 74HC-series CMOS devices and typically operate over a supply voltage range of 2.0 V to 6.0 V, with standard CMOS input thresholds and output drive characteristics as specified in their respective manufacturer datasheets.
Which device is better for serial data conversion, and which is better for data selection?
The 74HC166D is intended for serial data conversion because it is an 8-bit parallel-in/serial-out shift register. The 74HC153D is intended for data selection because it is a dual 4-input multiplexer.
Are the 74HC153D and 74HC166D available in the same temperature grade?
Both are commonly specified for the standard industrial temperature range of -40 °C to +85 °C or -40 °C to +125 °C, depending on the manufacturer and exact ordering part number. Designers should verify the specific datasheet for the chosen vendor.
Can the 74HC153D be used to expand the input capacity of the 74HC166D?
Yes, in principle. The 74HC153D can select among multiple data sources, and its output can feed a parallel input of the 74HC166D. However, timing, loading, and control logic must be validated against the datasheets of both devices.
What are the key control inputs for each device?
The 74HC153D has two select inputs (S0, S1) and two active-low enable inputs (Ea, Eb) for its two multiplexer sections. The 74HC166D has a shift/load control, a clock input, a serial input, and eight parallel data inputs, along with an asynchronous clear input on some variants.