74HC373D vs 74HC374D

The 74HC374D is an octal D-type flip-flop with edge-triggered clock inputs, while the 74HC373D is an octal D-type transparent latch with level-sensitive enable inputs. The 74HC374D captures data on the rising edge of the clock (CP), whereas the 74HC373D transfers data to the outputs when the latch enable (LE) is high and holds the last data when LE goes low.

Yes, both devices are typically offered in the same SOIC-20 package and share an identical pinout: pins 1 and 11 are control inputs (OE and CP for the 374D; OE and LE for the 373D), pins 2–9 are data inputs (D0–D7), pins 12–19 are data outputs (Q0–Q7), and pin 10 is GND with pin 20 as VCC. However, always verify the specific manufacturer datasheet because pinout can vary by package and logic family variant.

Not without design review. Although they are pin-compatible in many packages, the control input functions differ: the 374D requires a clock edge to update outputs, while the 373D is transparent when the latch enable is high. A circuit designed for a 373D may not function correctly with a 374D unless the control signal timing and logic are adapted.

Both are 74HC high-speed CMOS octal D-type devices typically rated for a supply voltage range of 2.0 V to 6.0 V, with maximum propagation delay on the order of 15 ns to 20 ns at 4.5 V and 25°C depending on the manufacturer. They provide standard CMOS input and output characteristics, including high noise immunity and low power consumption, but exact limits must be taken from the specific manufacturer datasheet.

Both devices have an active-low output enable (OE) that places the eight outputs in a high-impedance state when high. The OE function is functionally equivalent in both parts; the difference lies in the data-capture control: the 374D uses an edge-triggered clock (CP), while the 373D uses a level-sensitive latch enable (LE).

The 74HC373D is generally preferred for transparent latching or bus-holding because its level-sensitive latch enable allows data to flow through when enabled and hold the last value when disabled. The 74HC374D is better suited for synchronous, edge-triggered data transfer where state changes must occur only on a clock edge.

Both are commonly specified for the industrial temperature range of −40°C to +85°C or −40°C to +125°C depending on the manufacturer and suffix. The exact temperature grade must be confirmed from the ordering code and the manufacturer datasheet, as it is not identical across all sources.

The 74HC374D is typically used in synchronous data registers, shift registers, and clocked storage applications. The 74HC373D is commonly used in address latching for multiplexed buses, transparent data latches, and I/O port expansion where level-sensitive capture is required.