SN74279N3 Texas Instruments Integrated Circuit (Dual-In-Line Packages) In Stock
The SN74279N3 is a quad S-R latch integrated circuit from Texas Instruments in the TTL logic family, providing four independent set-reset latches in a 16-pin PDIP package. Two of the latches include dual S inputs for added flexibility, operating from a 4.75 V to 5.25 V supply over a 0 °C to 70 °C commercial temperature range. Designed for data storage, debouncing, and state-holding functions in digital logic systems.
- Manufacturer
- Texas Instruments
- Package
- Dual-In-Line Packages
- Pin Count
- 16
- Lifecycle
- OBSOLETE
- Datasheet
- SN74279N3 Datasheet PDF
- Category
- Integrated Circuit
- Temp Range
- ?°C to 70.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of SN74279N3?
- Quad S-R latch with 4 independent set-reset storage elements per package
- Two latches feature dual S inputs enabling OR-tied set control for flexible logic
- TTL-compatible inputs and outputs with 16 mA sink current drive capability
- Propagation delay of approximately 20 ns at 5 V supply
- 16-pin PDIP package for breadboard prototyping and through-hole PCB assembly
- Commercial temperature rating: 0 °C to 70 °C
What is SN74279N3 used for?
The SN74279N3 is used in digital systems for switch debouncing, contact bounce elimination, and simple state-holding latches in control panels and relay driver circuits. It also appears in legacy TTL-based data buffers, status registers, and glue logic designs where a compact quad latch in a through-hole PDIP package is preferred for ease of rework and prototyping.
What are the specifications of SN74279N3?
| Pbfree Code | No |
| YTEOL | 0 |
| Additional Feature | WITH DUAL S INPUT FOR TWO FUNCTIONS |
| Family | TTL/H/L |
| JESD-30 Code | R-PDIP-T16 |
| Load Capacitance (CL) | 15pF |
| Logic IC Type | R-S LATCH |
| Max I(ol) | 0.016A |
| Number of Bits | 2 |
| Number of Functions | 4 |
| Output Polarity | TRUE |
| Package Body Material | PLASTIC/EPOXY |
| Package Equivalence Code | DIP16,.3 |
| Package Shape | RECTANGULAR |
| Package Style | IN-LINE |
| Peak Reflow Temperature (Cel) | NOT SPECIFIED |
| Power Supply Current-Max (ICC) | 30mA |
| Prop. Delay@Nom-Sup | 27ns |
| Propagation Delay (tpd) | 27ns |
| 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 |
| Trigger Type | LOW LEVEL |
| ## SN74279N3 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 |
Where can I find the SN74279N3 datasheet?
SN74279N3 Datasheet DownloadOfficial datasheet from Texas Instruments
What are equivalent replacements for SN74279N3?
Compatible alternatives and drop-in replacements for SN74279N3:
suggested
suggested
suggested
suggested
R-S Latch, TTL/H/L Series, 4-Func, Low Level Triggered, 2-Bit, True Output, TTL, PDIP16
Frequently Asked Questions
How many latches does the SN74279N3 contain, and which ones have dual S inputs?
The SN74279N3 contains 4 independent S-R latches. Two of the four latches include dual S inputs, meaning the SET function on those latches is activated by either of the two S inputs being asserted low. This dual-input feature provides OR-wired set control without extra external gates, saving board space in TTL designs operating at 5 V.
For a mechanical switch debounce circuit running at 5 V, how quickly does the SN74279N3 resolve the output state?
In a debounce application, the SN74279N3 resolves the latch output within approximately 20 ns of the first valid set or reset edge at 5 V. Once the latch is set or reset by the initial keypress, subsequent bounce transitions on the other input line do not change the output, because both S and R cannot be simultaneously asserted in a standard debounce configuration.
What is the output drive capability of the SN74279N3, and can it directly drive standard TTL loads?
The SN74279N3 output can sink up to 16 mA (IOL) at a guaranteed low-level output voltage of 0.4 V, and source up to 0.4 mA (IOH). These parameters are compatible with standard TTL fan-out of approximately 10 unit loads per output, allowing direct connection to TTL gates, NAND inputs, or LED indicators with a series current-limiting resistor in 5 V systems.
Is the SN74279N3 suitable for designs that require operation below 0 °C?
No, the SN74279N3 is specified for a commercial temperature range of 0 °C to 70 °C. For applications requiring operation below 0 °C, such as outdoor equipment or industrial environments down to -40 °C, the SN54279 military-grade variant or equivalent CMOS logic devices rated for -40 °C to 85 °C or wider ranges should be selected instead.
How does the SN74279N3 compare in footprint to modern CMOS alternatives for quad latch designs?
The SN74279N3 occupies a 16-pin PDIP footprint measuring approximately 19.3 mm × 6.35 mm, which is significantly larger than modern CMOS alternatives such as the 74HC279 in a 16-pin SOIC (approximately 9.9 mm × 3.9 mm) or a 16-pin TSSOP (approximately 5.0 mm × 4.4 mm). However, the PDIP form factor suits through-hole prototyping and rework-friendly industrial applications where SMD assembly is not available.
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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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