CD74HC688NS Texas Instruments Integrated Circuit (Small Outline Packages) In Stock
The CD74HC688NS is an 8-bit magnitude comparator IC with an active-low A=B output, implementing a full 8-bit equality comparison in a 20-pin Small Outline package. It operates in the HC high-speed CMOS logic family with wide supply voltage compatibility and low power consumption. Available from authorized distributors with worldwide shipping.
- Manufacturer
- Texas Instruments
- Package
- Small Outline Packages
- Pin Count
- 20
- Lifecycle
- ACTIVE
- Datasheet
- CD74HC688NS Datasheet PDF
- Category
- Integrated Circuit
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- 8-bit parallel magnitude comparator with dedicated active-low A=B output for fast single-cycle equality detection
- High-speed CMOS (HC) logic family with wide VCC range and low quiescent current for battery-powered and low-power embedded applications
- 20-pin SOIC package enables compact PCB integration of full 8-bit comparison without external logic in address decoding and data validation circuits
Applications
The CD74HC688NS is widely used in microprocessor-based systems for address decoding, where it compares an 8-bit address bus against a fixed reference to generate chip-select signals. It is also suitable for data validation, byte comparison in communication protocols, and equality detection in digital control systems. The active-low output simplifies interfacing with CS-active-low memory and peripheral devices.
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
Alternate & Equivalent Parts
Compatible alternatives and drop-in replacements for CD74HC688NS:
Magnitude Comparator, HC/UH Series, 8-Bit, Inverted Output, CMOS, PDSO20
Frequently Asked Questions
What does the CD74HC688NS compare and what is its output format?
The CD74HC688NS performs an 8-bit magnitude comparison between two parallel input buses (P and Q) and asserts an active-low output when both 8-bit values are equal (P=Q). This single-output design is optimized for equality detection, making it ideal for address decoding and byte-level data comparison in digital systems.
What logic family does the CD74HC688NS belong to?
The CD74HC688NS belongs to the HC (High-speed CMOS) logic family. HC devices operate over a wide supply voltage range, typically 2V to 6V, and offer low quiescent power consumption combined with fast propagation delays. They are TTL input-voltage compatible and widely used in modern digital logic designs.
What package does the CD74HC688NS use and how many pins does it have?
The CD74HC688NS comes in a 20-pin Small Outline Integrated Circuit (SOIC) package, designated 20-SO. This surface-mount package supports automated PCB assembly and is compact enough for most board layouts while providing the 16 data input pins, one enable input, one output, and power supply pins needed for full 8-bit comparison.
How can the CD74HC688NS be used in address decoding applications?
In address decoding applications, one input port of the CD74HC688NS is connected to the address bus lines, while the other port is set to the target address via hardwired connections or DIP switches. When the CPU outputs the matching address, the active-low P=Q output asserts, generating a chip-select signal for the corresponding memory or peripheral device without requiring additional logic gates.
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About Texas Instruments
Texas Instruments (TI) is a global semiconductor company headquartered in Dallas, Texas. TI designs and manufactures analog and embedded processing chips used in industrial, automotive, consumer, communications, and enterprise systems.
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