Part A
74HC373D
NXP USA Inc.
- Lifecycle
- Active
- Stock
- 3870 PCS
- Package
- SOIC-14
- Series
- Lógica - Latches
Replacement verdict
Compatible functional replacement candidate
The 74HC373D and 74HC377D,652 are both octal D-type flip-flops in the 74HC logic family, sharing identical supply voltage, package, and temperature specifications. However, they differ in latch enable architecture and pinout, so the 74HC377D,652 is a functional replacement candidate for the 74HC373D only when the design accommodates the different control signal arrangement and clocked versus transparent operation.
Logic Function
High match
Supply Voltage Range
High match
Control Input Architecture
Validation required
Pin Configuration
Validation required
Parts at a glance
Part B
74HC377D,652
NXP USA Inc.
- Lifecycle
- Active
- Stock
- 2545 PCS
- Series
- Lógica - Flip Flops
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74HC373D | 74HC377D,652 | Why it matters |
|---|---|---|---|
| Logic Type | D-Type Transparent Latch (Octal) | D-Type Flip-Flop (Octal) | Latches are level-triggered (transparent when enable is active), while flip-flops are edge-triggered; this fundamentally changes timing behavior and prevents direct functional substitution. |
| Trigger Type | Level-triggered (Latch Enable) | Positive-edge triggered (Clock) | Edge-triggered devices capture data only at the clock transition, whereas latches pass data through while enabled, affecting circuit timing and race conditions. |
| Control Input | Latch Enable (LE) and Output Enable (OE) | Clock (CP) and Clock Enable (CE) | Different control signals mean the pinout and control logic differ, so the parts are not pin-to-pin or function-to-function interchangeable. |
| Output Enable | Yes (active-low OE for 3-state outputs) | No dedicated OE (outputs always active) | The 74HC373D can place outputs in high-impedance state for bus sharing, while the 74HC377D cannot, limiting its use in multiplexed bus applications. |
| Number of Bits | 8 | 8 | Both are octal devices, so they handle the same data width, which is important for matching bus widths in a design. |
| Supply Voltage Range | 2 V to 6 V | 2 V to 6 V | Matching supply ranges ensures both parts operate in the same logic family voltage window (HC family), supporting compatibility in mixed designs. |
| Output Type | 3-State | 3-State | Both provide 3-state outputs, allowing bus connection, though the 74HC377D lacks a dedicated output enable pin. |
| Package | SOIC-20 (D suffix) | SOIC-20 (D suffix) | Same package footprint allows PCB layout compatibility, though pin functions differ between the two devices. |
| Logic Family | 74HC | 74HC | Same logic family ensures compatible input/output voltage thresholds and drive characteristics. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Identical temperature ratings mean both are suitable for the same industrial and automotive-grade environments. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC373D | 74HC377D,652 |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | 74HC | 74HC |
| Part Status | Active | Active |
| Function | - | Standard |
| Type | - | D-Type |
| Output Type | Tri-State | Non-Inverted |
| Number of Elements | - | 1 |
| Number of Bits per Element | - | 8 |
| Clock Frequency | - | 83 MHz |
| Max Propagation Delay @ V Max CL | - | 27ns @ 6V, 50pF |
| Trigger Type | - | Positive Edge |
| Current - Output High Low | 7.8mA, 7.8mA | 5.2mA, 5.2mA |
| Voltage - Supply | 2V ~ 6V | 2V ~ 6V |
| Current - Quiescent (Iq) | - | 8 µA |
| Input Capacitance | - | 3.5 pF |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 125°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
| Logic Type | D-Type Transparent Latch | - |
| Circuit | 1:8 | - |
| Independent Circuits | 1 | - |
| Delay Time - Propagation | 30ns | - |
Frequently asked questions
What is the primary functional difference between the 74HC373D and the 74HC377D,652?
The 74HC373D is an octal transparent D-type latch with 3-state outputs, meaning its outputs follow the inputs while the latch enable (LE) is HIGH and hold the last data when LE goes LOW. The 74HC377D,652 is an octal D-type flip-flop with 3-state outputs that is positive-edge triggered by a clock (CP) input, so data is captured only on the LOW-to-HIGH clock transition.
Are the 74HC373D and 74HC377D,652 pin-compatible?
No. Both are 20-pin devices, but their pin functions differ. The 74HC373D uses pin 11 as Latch Enable (LE) and pin 1 as Output Enable (OE). The 74HC377D,652 uses pin 11 as Clock (CP) and pin 1 as Output Enable (OE). Because the control pin functions differ, they are not direct drop-in replacements without accounting for the different control signal behavior.
Can the 74HC373D directly replace the 74HC377D,652 in an existing design?
Not directly. The 74HC373D is level-sensitive (transparent latch) while the 74HC377D,652 is edge-triggered (flip-flop). Substitution requires verifying that the system's control signal timing, setup and hold requirements, and output enable behavior are compatible with the different latching mechanism. The pinout difference on the control pin must also be addressed.
What are the key operating voltage and logic family specifications for both devices?
Both the 74HC373D and 74HC377D,652 are HC-family CMOS devices typically specified for a supply voltage range of 2.0 V to 6.0 V, with standard 74HC input thresholds and CMOS-compatible outputs. They are commonly used in 3.3 V and 5 V logic systems. Exact limits should be confirmed against the respective manufacturer datasheets.
What is the difference in data capture behavior between the two devices?
The 74HC373D captures data asynchronously: when LE is HIGH, the Q outputs continuously reflect the D inputs (transparent mode), and when LE transitions LOW, the current D data is latched. The 74HC377D,652 captures data synchronously: the D input is sampled only at the LOW-to-HIGH transition of CP, and the output remains stable until the next clock edge, regardless of subsequent D input changes.
Do both devices provide 3-state outputs?
Yes. Both the 74HC373D and 74HC377D,652 feature 3-state (tri-state) outputs controlled by an Output Enable (OE) pin. When OE is asserted, the outputs are active; when OE is de-asserted, the outputs enter a high-impedance state, allowing the devices to share a common bus.
Which device is more suitable for bus-oriented synchronous data transfer?
The 74HC377D,652 is generally more suitable for synchronous bus-oriented data transfer because its edge-triggered flip-flop operation ensures data is captured at a defined clock edge, providing predictable timing and avoiding the transparency issues associated with level-sensitive latches. The 74HC373D is often used where transparent latching or asynchronous data holding is required.
What package type do the 74HC373D and 74HC377D,652 use?
Both devices are typically offered in a 20-pin SOIC package (the "D" suffix in the part numbers denotes SOIC). The 74HC377D,652 suffix indicates tape-and-reel packaging. Package dimensions and thermal characteristics should be verified from the specific manufacturer datasheet.