Part A
74HC393D
Toshiba Semiconductor et stockage
- Lifecycle
- Active
- Stock
- 2760 PCS
- Package
- SOIC-20
- Series
- Logique - compteurs, diviseurs
Replacement verdict
Not a drop-in replacement
The 74HC393D and 74HC377D,652 are functionally dissimilar logic ICs that cannot be interchanged in a design. The 74HC393D is a dual 4-bit binary ripple counter, while the 74HC377D,652 is an octal D-type flip-flop with enable. Their internal architectures, pin functions, and logic operations differ fundamentally, making direct substitution impossible without a complete circuit redesign.
Different logic function
Different output type
Different pin function
Different clocking scheme
Parts at a glance
Part B
74HC377D,652
NXP USA Inc.
- Lifecycle
- Active
- Stock
- 2545 PCS
- Series
- Logique - Triggers
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 | 74HC377D,652 | Why it matters |
|---|---|---|---|
| Logic Function | Dual 4-bit binary ripple counter | Octal D-type flip-flop with enable | Defines the core function; these devices are not functionally interchangeable as they perform counting versus data storage/register operations. |
| Number of Flip-Flops / Counters | 2 independent 4-bit counters (8 flip-flops total) | 8 D-type flip-flops | Determines how many bits or channels the device can process, affecting the logic capacity in a design. |
| Output Type | Buffered counter outputs (Q0-Q3 per counter) | 3-state non-inverting D-type outputs | 3-state outputs allow bus sharing, while counter outputs are always driven; this affects system architecture and bus interfacing. |
| Clock Input | Negative-edge triggered (ripple clock) | Positive-edge triggered (single clock) | Clock edge polarity must match the driving logic; a mismatch will cause incorrect latching or counting behavior. |
| Control Inputs | Master reset (active LOW) per counter | Clock enable (active LOW) and output enable (active LOW) | Control pins determine how the device is initialized and gated; different control schemes require different driving logic. |
| Data Inputs | None (counts clock pulses) | 8 parallel D inputs | Presence or absence of data inputs fundamentally changes how the device is used in a circuit. |
| Supply Voltage Range | 2.0 V to 6.0 V | 2.0 V to 6.0 V | Both support the standard HC-family supply range, so power supply compatibility is identical. |
| Logic Family | 74HC (High-speed CMOS) | 74HC (High-speed CMOS) | Same logic family ensures compatible input/output voltage thresholds and noise margins when interfacing. |
| Package | SO14 (14-pin SOIC) | SO20 (20-pin SOIC) | Different pin counts and footprints mean the PCB layout must be redesigned; they are not drop-in replacements. |
| Propagation Delay (typical at 5 V) | ~14 ns (clock to output) | ~15 ns (clock to output) | Timing characteristics affect maximum operating frequency and setup/hold requirements in synchronous designs. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC393D | 74HC377D,652 |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | 74HC | 74HC |
| Part Status | Active | Active |
| Function | - | Standard |
| Type | - | D-Type |
| Output Type | - | Non-Inverted |
| Number of Elements | 2 | 1 |
| Number of Bits per Element | 4 | 8 |
| Clock Frequency | - | 83 MHz |
| Max Propagation Delay @ V Max CL | - | 27ns @ 6V, 50pF |
| Trigger Type | Negative Edge | Positive Edge |
| Current - Output High Low | - | 5.2mA, 5.2mA |
| Voltage - Supply | 2 V ~ 6 V | 2V ~ 6V |
| Current - Quiescent (Iq) | - | 8 µA |
| Input Capacitance | - | 3.5 pF |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 125°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
| Logic Type | Binary Counter | - |
| Direction | Up | - |
| Count Rate | 32 MHz | - |
Frequently asked questions
What are the primary functional differences between the 74HC393D and the 74HC377D,652?
The 74HC393D is a dual 4-bit binary ripple counter, while the 74HC377D,652 is an octal D-type flip-flop with a clock enable input. They perform fundamentally different logic functions and are not interchangeable.
Are the 74HC393D and 74HC377D,652 pin-compatible?
No. The 74HC393D is typically supplied in a 14-pin SOIC package, whereas the 74HC377D,652 is supplied in a 20-pin SOIC package. Pin counts, pin assignments, and package dimensions differ, so they cannot share the same PCB footprint.
Can the 74HC393D be used as a direct substitute for the 74HC377D,652 in a registered data bus application?
No. The 74HC377D,652 provides eight edge-triggered D-type flip-flops with a common clock and clock enable, suitable for bus registration. The 74HC393D provides two independent 4-bit ripple counters and lacks the parallel data storage and clock-enable functionality required for bus registration.
What are the key operating voltage and logic family specifications shared by both devices?
Both devices are members of the 74HC high-speed CMOS logic family and are specified for operation over a supply voltage range of 2.0 V to 6.0 V, with typical characteristics at 5.0 V. They are not 5 V tolerant when operated at lower supply voltages unless stated otherwise in the manufacturer datasheet.
Which device is better suited for frequency division or counting applications?
The 74HC393D is the appropriate choice for frequency division and counting because it contains two independent 4-bit binary ripple counters. The 74HC377D,652 is an octal D-type flip-flop and does not provide internal counting or ripple-carry stages.
Which device is better suited for capturing and holding parallel data?
The 74HC377D,652 is designed for parallel data capture and storage, featuring eight D-type flip-flops with a common clock and clock enable. The 74HC393D does not provide parallel data latching or registration.
Do both devices support the same clocking or triggering scheme?
No. The 74HC393D counters are negative-edge triggered and ripple internally. The 74HC377D,652 flip-flops are positive-edge triggered and update all eight outputs simultaneously on the rising clock edge when the clock enable is active.
Are the 74HC393D and 74HC377D,652 available in the same package options?
No. The 74HC393D is commonly offered in 14-pin SOIC and other 14-pin packages. The 74HC377D,652 is commonly offered in 20-pin SOIC and other 20-pin packages. Package options differ and must be verified against the specific manufacturer datasheet.