SN74LS147J Texas Instruments Integrated Circuit (Dual-In-Line Packages) In Stock
SN74LS147J is a 9-to-4 line priority encoder in the LS logic family, housed in a ceramic 16-pin DIP package. It encodes the highest-priority active-low input among 9 input lines into a 4-bit BCD output at 15 pF load capacitance. Used for keyboard encoding, interrupt priority controllers, and analog-to-digital converters in legacy and industrial digital systems.
- Manufacturer
- Texas Instruments
- Package
- Dual-In-Line Packages
- Pin Count
- 16
- Lifecycle
- OBSOLETE
- Datasheet
- SN74LS147J Datasheet PDF
- Category
- Integrated Circuit
- Temp Range
- ?°C to 70.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- 9-to-4 line priority encoder with BCD output
- Active-low inputs with priority logic for highest-active encoding
- LS family: TTL-compatible 5 V operation
- 15 pF load capacitance per output
- Ceramic glass-sealed 16-pin DIP for high-reliability environments
- Single-function dedicated encoder logic
Applications
The SN74LS147J is used in keyboard and keypad encoder circuits to convert 9 individual key-press inputs into a 4-bit BCD code for microcontroller or bus interfaces. Priority interrupt controllers in industrial PLCs and legacy embedded systems use it to encode up to 9 interrupt sources into a 4-bit priority index. It also appears in analog-to-digital converter front-ends where 9 discrete threshold comparator outputs need to be encoded into a digital word.
Specifications
| YTEOL | 0 |
| Additional Feature | 9 TO 4 LINE PRIORITY ENCODER |
| Family | LS |
| JESD-30 Code | R-GDIP-T16 |
| Load Capacitance (CL) | 15pF |
| Logic IC Type | ENCODER |
| Number of Bits | 9 |
| Number of Functions | 1 |
| Package Body Material | CERAMIC, GLASS-SEALED |
| Package Equivalence Code | DIP16,.3 |
| Package Shape | RECTANGULAR |
| Package Style | IN-LINE |
| Peak Reflow Temperature (Cel) | NOT SPECIFIED |
| Power Supply Current-Max (ICC) | 20mA |
| Propagation Delay (tpd) | 23ns |
| Qualification Status | Not Qualified |
| Supply Voltage-Max (Vsup) | 5.25V |
| Supply Voltage-Min (Vsup) | 4.75V |
| Supply Voltage-Nom (Vsup) | 5V |
| Surface Mount | NO |
| Technology | TTL |
| Temperature Grade | COMMERCIAL |
| Terminal Form | THROUGH-HOLE |
| Terminal Pitch | 2.54mm |
| Terminal Position | DUAL |
| Time@Peak Reflow Temperature-Max (s) | NOT SPECIFIED |
| ## SN74LS147J Alternates Showing results | Image |
| Package | Dual-In-Line Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| HTS Code | 8542.39.00.60 |
Alternate & Equivalent Parts
Compatible alternatives and drop-in replacements for SN74LS147J:
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suggested
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suggested
Frequently Asked Questions
How many input lines does the SN74LS147J encode, and what output format does it produce?
The SN74LS147J encodes 9 active-low input lines into a 4-bit BCD (binary-coded decimal) output representing the highest-priority active input, making it suitable for keyboard and interrupt priority circuits operating at 5 V TTL levels.
Why is the ceramic DIP package of the SN74LS147J significant for industrial or military designs?
The ceramic glass-sealed 16-pin DIP package withstands wider temperature ranges and harsh environments better than plastic DIP versions, meeting the reliability requirements of mil-spec and industrial control systems that must operate across extended temperature cycles.
In a 9-key keyboard encoder, how does priority resolution work on the SN74LS147J when two keys are pressed simultaneously?
When multiple inputs are active simultaneously, the device encodes only the highest-numbered (highest-priority) active input into the 4-bit BCD output, and lower-priority inputs are ignored, ensuring a deterministic 4-bit code regardless of how many keys are pressed at once.
Can the SN74LS147J be cascaded to encode more than 9 inputs?
Cascading multiple SN74LS147J devices is possible with external priority logic to extend encoding beyond 9 inputs; for example, two devices with an OR gate on the enable inputs can encode up to 16 lines into a 4-bit output, though propagation delays add roughly 15 ns per stage.
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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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