SN54HC688FK Texas Instruments Integrated Circuit (Ceramic Dual-In-Line Packages) In Stock
SN54HC688FK is an 8-bit identity comparator from Texas Instruments in the HC/UH logic family, supporting cascadable operation with inverted output polarity and a 50 pF load capacitance rating. Housed in a 20-pin ceramic QCC package, it suits military-grade and high-reliability digital comparison circuits.
- Manufacturer
- Texas Instruments
- Package
- Ceramic Dual-In-Line Packages
- Pin Count
- 20
- Lifecycle
- OBSOLETE
- Datasheet
- SN54HC688FK Datasheet PDF
- Category
- Integrated Circuit
- Temp Range
- -40.0°C to 85.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of SN54HC688FK?
- 8-bit identity comparator with cascadable architecture
- Inverted output polarity for active-low enable designs
- 50 pF load capacitance (CL) on outputs
- HC/UH logic family for broad voltage compatibility
- 20-pin ceramic, metal-sealed cofired QCC package (S-CQCC-N20)
- Single-function logic IC for simplified board integration
- Military-grade ceramic package for harsh environments
What is SN54HC688FK used for?
The SN54HC688FK is used in address decoding, memory bank selection, and microprocessor bus validation circuits where an 8-bit bit-for-bit comparison between two data words must be performed reliably. Its cascadable design allows multiple devices to be chained for wider comparison widths without external logic. The ceramic package suits aerospace, defense, and industrial environments that demand operation across extended temperature ranges.
What are the specifications of SN54HC688FK?
| YTEOL | 0 |
| Additional Feature | CASCADABLE |
| Family | HC/UH |
| JESD-30 Code | S-CQCC-N20 |
| Load Capacitance (CL) | 50pF |
| Logic IC Type | IDENTITY COMPARATOR |
| Number of Bits | 8 |
| Number of Functions | 1 |
| Output Polarity | INVERTED |
| Package Body Material | CERAMIC, METAL-SEALED COFIRED |
| Package Equivalence Code | LCC20,.35SQ |
| Package Shape | SQUARE |
| Package Style | CHIP CARRIER |
| Power Supply Current-Max (ICC) | 50mA |
| Propagation Delay (tpd) | 313ns |
| Qualification Status | Not Qualified |
| Supply Voltage-Max (Vsup) | 6V |
| Supply Voltage-Min (Vsup) | 2V |
| Supply Voltage-Nom (Vsup) | 5V |
| Surface Mount | YES |
| Technology | CMOS |
| Temperature Grade | INDUSTRIAL |
| Terminal Form | NO LEAD |
| Terminal Pitch | 1.27mm |
| Terminal Position | QUAD |
| Package | Ceramic Dual-In-Line Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| HTS Code | 8542.39.00.60 |
Where can I find the SN54HC688FK datasheet?
SN54HC688FK Datasheet DownloadOfficial datasheet from Texas Instruments
What are equivalent replacements for SN54HC688FK?
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
How wide is the comparison word in the SN54HC688FK and can it be cascaded for wider data paths?
The SN54HC688FK performs an 8-bit identity comparison and is designed to be cascaded, so multiple devices can be combined to compare 16-bit, 24-bit, or wider data words without additional glue logic, keeping board-level design simple.
Why choose the ceramic QCC package of the SN54HC688FK over plastic alternatives?
The 20-pin ceramic, metal-sealed cofired package (S-CQCC-N20) offers superior hermeticity and thermal stability, making SN54HC688FK suitable for aerospace and defense applications that must pass military qualification and operate reliably under temperature extremes and mechanical stress.
In which digital logic circuits is the SN54HC688FK typically deployed?
This device is commonly used in address-decode circuits and memory bank selection where an 8-bit comparator with an active-low (inverted) output can enable or disable a chip-select line when the CPU address bus matches a predefined 8-bit base address.
What is the specified load capacitance for the SN54HC688FK outputs?
The SN54HC688FK is rated for a 50 pF load capacitance (CL) on its outputs, which determines the maximum allowable capacitive bus loading for meeting the timing parameters defined in the HC/UH logic family datasheet.
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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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