7404 NOT Gate IC Pin Configuration Datasheet7404/74LS04

Technical Guide 7404 / 74LS04: Hex Inverter High-Speed TTL

The 74LS04 is not merely a basic logic IC; it is the backbone of signal inversion in high-speed, low-power digital systems. Based on Low-power Schottky (LS) technology, this component integrates six independent inverters into a single package, optimizing PCB real estate and reducing propagation latency to critical levels for bus synchronization. Ignoring its input capacitance or underestimating its Fan-out is a direct recipe for uncontrollable thermal noise and switching failures.

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⚠️ Survival Limits

Any excursion beyond these ranges will result in immediate silicon degradation or erratic behavior that will waste hours of your time on the oscilloscope.

• Supply Voltage ($V_{CC}$): 7V (Absolute Maximum).
• Input Voltage ($V_I$): 5.5V (7V on specific variants).
• Output Current ($I_{OH}$): -0.4 mA (Source limit).
• Output Current ($I_{OL}$): 8 mA / 16 mA (Sink limit depending on variant).
• Junction Temperature ($T_J$): 150°C.

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Pinout and Physical Reference: Terminal Configuration

The design follows the 14-pin industry standard. If you attempt to power the chip through signal pins because "they look similar," prepare to witness the release of the magic smoke.

Pin	Name	Function
1	1A	Inverter 1 Input
2	1Y	Inverter 1 Output
3	2A	Inverter 2 Input
4	2Y	Inverter 2 Output
5	3A	Inverter 3 Input
6	3Y	Inverter 3 Output
7	GND	Ground Reference (0V)
8	4Y	Inverter 4 Output
9	4A	Inverter 4 Input
10	5Y	Inverter 5 Output
11	5A	Inverter 5 Input
12	6Y	Inverter 6 Output
13	6A	Inverter 6 Input
14	VCC	Supply Voltage (+5V nominal)

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Laboratory Specifications

Real-world performance isn't measured in marketing datasheets, but in transient response under reactive loads.

Parameter	Symbol	Min	Typ	Max	Unit
Supply Voltage	$V_{CC}$	4.75	5.00	5.25	V
High-Level Input Threshold	$V_{IH}$	2.0	-	-	V
Low-Level Input Threshold	$V_{IL}$	-	-	0.8	V
Propagation Delay (L-to-H)	$t_{PLH}$	-	9	15	ns
Propagation Delay (H-to-L)	$t_{PHL}$	-	10	15	ns

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Applied Engineering

Analyzing the 74LS04 requires understanding that each gate is a miniature gain stage designed to correct TTL signal degradation.

Logic Diagram Analysis: The simplicity of the diagram conceals the internal complexity of Schottky transistors. Each inverter performs the fundamental logic operation:

$$Y = \overline{A}$$

This block is vital for generating complementary clock signals, preventing cross-conduction states in low-power H-bridges.

Internal Architecture Analysis: The schematic reveals why the Transient Response is so superior to a generic bipolar transistor. By using Schottky diodes in parallel with the base-collector junction, the transistor is prevented from entering deep saturation.

• The Problem: In mediocre designs, charge accumulation in the base slows down the turn-off time.
• BySMax Solution: The 74LS04 utilizes these "clamps" to divert excess current, allowing the component to switch logic states in less than 15ns, ideal for address decoders in embedded systems.

Oscillator Application Analysis: Using three gates in a ring to create an oscillator is a classic technique. However, without a 0.1µF ceramic decoupling capacitor near pin 14, trace inductance will turn your PCB into an electromagnetic interference (EMI) antenna. The design ensures that negative feedback maintains frequency stability, provided the Safe Operating Area of the output current is respected.

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BySMax Selection Criteria

The 74LS04 in our inventory has been selected for its robustness against Thermal Throttling and its consistency in $V_{OH}$ output voltage. We do not accept low-fidelity clones that collapse under 4mA loads. If you are looking for signal integrity and an architecture that respects your CPU's setup and hold times, this is the hardware you need.

Learn about NOT logic

This video provides a practical demonstration of the truth table and the real-world operation of the IC in a laboratory environment.