Part A
74HC373D
NXP USA Inc.
- Lifecycle
- Active
- Stock
- 3870 Stückzahl
- Package
- SOIC-14
- Series
- Logic-Verriegelungen
Replacement verdict
Not a drop-in replacement
The 74HC393D and 74HC373D are functionally unrelated despite sharing the 74HC logic family and SOIC-16 package. The 74HC393D is a dual 4-bit binary ripple counter, while the 74HC373D is an octal transparent D-type latch with 3-state outputs. Their internal architectures, pin functions, and logic operations are fundamentally different, making direct substitution impossible in any design. Neither device can replicate the other's core function without additional circuitry and complete redesign of the surrounding interface.
Different logic function
Different output type
Different pinout
Different clock architecture
Parts at a glance
Part B
74HC393D
Toshiba Halbleiter und Speicher
- Lifecycle
- Active
- Stock
- 2760 Stückzahl
- Package
- SOIC-20
- Series
- Logik für Zähler, Teiler
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74HC393D | 74HC373D | Why it matters |
|---|---|---|---|
| Logic Function | Dual 4-bit binary ripple counter | Octal D-type transparent latch (3-state) | Defines the fundamental function; these devices are not functionally interchangeable as they perform completely different logic operations. |
| Number of Flip-Flops / Latches | 8 (two independent 4-bit counters) | 8 latches (single octal latch) | Indicates the number of storage elements; affects how many bits can be counted or latched simultaneously. |
| Output Type | Buffered push-pull (totem-pole) | 3-state (tri-state) | 3-state outputs allow bus sharing; push-pull outputs cannot be tied together, affecting system architecture. |
| Clock / Enable Inputs | Clock and reset per counter | Latch enable (LE) and output enable (OE) | Determines control signals required; counters use clock edges while latches use level-sensitive enables. |
| Trigger Mechanism | Negative-edge triggered | Level-sensitive (transparent) | Edge-triggered devices change state on clock transitions; transparent latches pass data while enabled, affecting timing behavior. |
| Propagation Delay (typical at 4.5V) | ~14 ns (clock to output) | ~13 ns (LE to output) | Affects maximum operating frequency and timing margins in synchronous systems. |
| Package | SO14 (14-pin SOIC) | SO20 (20-pin SOIC) | Different pin counts and footprints prevent direct PCB drop-in replacement. |
| Supply Voltage Range | 2.0 V to 6.0 V | 2.0 V to 6.0 V | Both support standard HC-family supply voltages, allowing use in similar logic-level systems. |
| Pin Count | 14 | 20 | Pin count determines package size and PCB layout compatibility; different counts mean they are not pin-compatible. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC373D | 74HC393D |
|---|---|---|
| Series | 74HC | 74HC |
| Part Status | Active | Active |
| Logic Type | D-Type Transparent Latch | Binary Counter |
| Circuit | 1:8 | - |
| Output Type | Tri-State | - |
| Voltage - Supply | 2V ~ 6V | 2 V ~ 6 V |
| Independent Circuits | 1 | - |
| Delay Time - Propagation | 30ns | - |
| Current - Output High Low | 7.8mA, 7.8mA | - |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
| Direction | - | Up |
| Number of Elements | - | 2 |
| Number of Bits per Element | - | 4 |
| Count Rate | - | 32 MHz |
| Trigger Type | - | Negative Edge |
Frequently asked questions
What are the primary functional differences between the 74HC393D and the 74HC373D?
The 74HC393D is a dual 4-bit binary ripple counter, while the 74HC373D is an octal D-type transparent latch with 3-state outputs. They perform entirely different logic functions and are not interchangeable.
Are the 74HC393D and 74HC373D pin-compatible in the SO14 package?
No. The 74HC393D is typically supplied in a 14-pin SO package (SO14), whereas the 74HC373D is typically supplied in a 20-pin SO package (SO20). They have different pin counts and pinouts, so they are not pin-compatible.
Can the 74HC393D and 74HC373D operate from the same supply voltage range?
Yes. Both devices are 74HC-family CMOS logic parts and operate over a specified supply voltage range of 2.0 V to 6.0 V, with typical operation at 5.0 V.
Does the 74HC373D have 3-state outputs while the 74HC393D does not?
Yes. The 74HC373D features 3-state outputs controlled by an output enable (OE) pin, allowing the outputs to be placed in a high-impedance state. The 74HC393D has standard push-pull counter outputs and does not provide a 3-state output mode.
What is the difference in output drive capability between the 74HC393D and 74HC373D?
Both devices are standard 74HC CMOS logic and provide symmetrical output drive. In the 74HC family, outputs are typically specified to drive 4 mA at 5 V, with the 74HC373D also supporting 3-state bus operation. Exact drive currents should be confirmed from the respective manufacturer datasheets.
Can the 74HC393D be used as a direct replacement for the 74HC373D in a bus latch application?
No. The 74HC393D is a counter and cannot perform the transparent latching or 3-state bus driving functions of the 74HC373D. A direct replacement is not possible.
Are both the 74HC393D and 74HC373D available in SO14 and SO20 surface-mount packages respectively?
Yes. The 74HC393D is commonly offered in the SO14 package, and the 74HC373D is commonly offered in the SO20 package. Package options may vary by manufacturer, so the specific datasheet should be consulted for exact ordering codes.