74HC14 Schmitt Trigger: Datasheet, Pinout and Application

74HC14 Pinout

Footprint

3D Model

74HC14 3D Model

The 74HC14 is identical in pinout to the LS14, LS04 and HC04. The device inputs are compatible with Standard CMOS outputs; with pullup resistors, they are compatible with LSTTL outputs. The HC14 is useful to “square up” slow input rise and fall times. Due to the hysteresis voltage of the Schmitt trigger, the HC14 finds applications in noisy environments.

•Output Drive Capability: 10 LSTTL Loads

• Outputs Directly Interface to CMOS, NMOS and TTL

• Operating Voltage Range: 2.0 to 6.0 V

• Low Input Current: 1.0 A

• High Noise Immunity Characteristic of CMOS Devices

• In Compliance With the JEDEC Standard No. 7A Requirements

• ESD Performance: HBM  2000 V; Machine Model  200 V

• Chip Complexity: 60 FETs or 15 Equivalent Gates

• These are Pb−Free Devices

• General-purpose logic

• PCs and notebooks

• TV, DVD, Set-Top Box

• Networking

• Digital systems

Consider the following scenarios to better understand how 74HC14 is used:

Case 1: You need to convert signal waveforms to square waveforms. Non-square waveforms can be converted to square waves using Schmitt trigger gates on the 74HC14. We can convert sinusoidal or triangular waves to square waves using the Schmitt trigger gate.

Case 2: When a logic inverter is required. This chip's inverter Schmitt triggers can generate output that is negated logic input. Inverted logics for controllers or digital electronics can be obtained using these chip gates.

When you wish to get rid of noise in digital electronics, use Case3. In digital circuits, noise creates significant errors, hence the 74HC14 chip is excellent.

The equivalent parts for 74HC14:

• MC14584

• CD40106

As previously stated, the 74HC14 includes six INVERTING SCHMITT TRIGGER GATES that can be used individually. The logic diagram can be summarized as follows.

74HC14 Logic Diagram

Now, to better understand how gates work, let's take a single gate and attach the power to the chip. Also, at the input, provide an analogue signal.

74HC14 Circuit

As shown in the circuit, we are giving a sinusoidal wave at the input and taking Vout as the output of the gate. Once we draw the input and output graph we will have something like this.

74HC14 Trigger Application

The Schmitt Trigger operates on a very basic principle: the output of an inverting Schmitt Trigger is LOW only when the input signal voltage level crosses the threshold voltage (+Vt).

As illustrated in the diagram, the output voltage (Vout) is HIGH until the input voltage (Vin) surpasses the threshold voltage (Vt+). The output voltage becomes LOW once it hits the threshold voltage. Until the input voltage falls below the low threshold voltage, the output voltage remains low (Vt-). The output voltage hits HIGH once it reaches that point. This cycle continues.

As illustrated in the graph, when a sinusoidal signal is used as an input, the result is a square wave. Each gate can be used in this manner to obtain the required output.

74HC14 Package

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