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onsemi DM74ALS27N
- Part No.:
- DM74ALS27N
- Manufacturer:
- onsemi
- Category:
- Gates and Inverters
- Package:
- 14-DIP (0.300", 7.62mm)
- Datasheet:
-
DM74ALS27N.pdf
- Description:
- IC GATE NOR 3CH 3-INP 14MDIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,772
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Product details
Overview
DM74ALS27N from Fairchild Semiconductor is a triple 3-input NOR gate logic IC in 14-lead PDIP package, operating at VCC = 4.5–5.5 V, with propagation delays as low as 3 ns (tPHL) and 4 ns (tPLH), output drive capability of ±112 mA (IO), and guaranteed performance across 0°C to +70°C ambient temperature - used in digital control logic, address decoding, and bus arbitration circuits.
For engineers reviewing the DM74ALS27N datasheet, pinout, applications, or equivalent options, key selection criteria include its TTL-compatible input thresholds (VIL = 0.8 V, VIH = 2.0 V), 50 pF switching characterization, pin-for-pin compatibility with standard Schottky and LS-TTL NOR gates, and PDIP packaging for through-hole prototyping and industrial control boards.
Technical Context
The DM74ALS27N implements three independent 3-input NOR gates using advanced oxide-isolated, ion-implanted Schottky TTL process technology. Each gate exhibits symmetrical input structure and rail-to-rail compatible output swing under specified load conditions (RL = 500 Ω, CL = 50 pF).
It operates strictly within TTL voltage domains: VIH ≥ 2.0 V guarantees HIGH recognition, VIL ≤ 0.8 V ensures LOW detection, and VOL ≤ 0.5 V at IOL = 8 mA supports noise-immune interfacing with downstream TTL inputs. No internal pull-ups, level-shifting, or open-collector configuration is present.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL power rails and tolerance against supply ripple. |
| tPHL / tPLH | 3 ns / 4 ns typical - enables high-speed combinational logic in clocked state machines and address decoders. |
| IOL / IOH | 8 mA / −0.4 mA - drives up to 10 standard TTL loads without external buffering. |
| VIL / VIH | 0.8 V / 2.0 V - provides robust noise margin (≥0.4 V) against ground bounce and crosstalk in dense PCB layouts. |
| Operating Temp | 0°C to +70°C - qualified for commercial-grade embedded control, instrumentation, and office equipment. |
| ICC (Outputs LOW) | 2–4 mA - reflects active-state power consumption during asserted output conditions. |
Pinout & Package
DM74ALS27N is housed in a 14-lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" wide, with 0.1" lead pitch and through-hole mounting. Thermal resistance θJA = 86.5°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3 | Input A, B, C of Gate 1 | Three independent logic inputs for first NOR gate; all must be LOW for HIGH output. |
| 4 | Output Y1 | Active-LOW NOR output of Gate 1; sinks up to 8 mA when LOW. |
| 5, 6, 7 | Input A, B, C of Gate 2 | Three independent logic inputs for second NOR gate. |
| 8 | GND | Power ground reference for all internal circuitry and I/O. |
| 9, 10, 11 | Input A, B, C of Gate 3 | Three independent logic inputs for third NOR gate. |
| 12 | Output Y3 | Active-LOW NOR output of Gate 3. |
| 13 | VCC | +5 V supply connection; bypass capacitor recommended near pin. |
| 14 | Output Y2 | Active-LOW NOR output of Gate 2. |
Key Features
| Feature | Design Value |
|---|---|
| Triple 3-input NOR function | Three fully isolated gates on one die - reduces board space vs. discrete gate arrays and simplifies routing in multi-channel logic systems. |
| Guaranteed AC specs at 50 pF | Propagation delay bounds (3–9 ns tPHL, 4–15 ns tPLH) validated under standardized capacitive load - eliminates guesswork in timing-critical paths. |
| TTL-compatible input thresholds | VIL ≤ 0.8 V and VIH ≥ 2.0 V ensure reliable interfacing with legacy 74LS/74S families without level shifters. |
| Pin-for-pin compatibility | Direct replacement for 74S27 and 74LS27 in PDIP footprint - enables drop-in upgrade path for speed and drive improvements. |
Applications
| Address Decoding | Bus Arbitration |
|---|---|
Use Scenario: Selecting memory or peripheral chips based on CPU address bus bits in microcontroller-based systems. IC Role / Device Role / Timing Role: Logic-level combinatorial decoder that asserts chip-select signals only when specific 3-bit address patterns occur. Use Value: Enables deterministic, glitch-free chip selection with sub-10 ns decision latency and TTL-level fanout support. | Use Scenario: Resolving contention between multiple masters sharing a common data bus in industrial PLC backplanes. IC Role / Device Role / Timing Role: Priority encoder front-end that generates grant signals based on encoded request lines. Use Value: Provides deterministic arbitration response within 9 ns (max tPHL), supporting real-time bus turnaround in deterministic control loops. |
| Control Signal Generation | Reset Logic Conditioning |
Use Scenario: Generating enable/disable strobes for DACs, ADCs, or display drivers in test equipment front-ends. IC Role / Device Role / Timing Role: Active-LOW gating element that combines status flags (e.g., BUSY, ERROR, READY) into a single inhibit signal. Use Value: Delivers 8 mA sink current per output to directly drive LED indicators or optocoupler inputs without added transistors. | Use Scenario: Synchronizing and debouncing asynchronous reset inputs before distribution to multiple ICs in a system-on-board. IC Role / Device Role / Timing Role: Glitch-filtering combiner that asserts system reset only when all upstream reset sources are stable and deasserted. Use Value: Leverages inherent NOR logic to implement "AND-of-inverted-signals" behavior with predictable setup/hold timing margins. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 3-input NOR gate applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS27N | Slower propagation (tPHL/tPLH = 10/15 ns typ), lower IOL (8 mA same), identical pinout and VCC range. | Lower-speed designs where timing margin exceeds 10 ns; preferred for ultra-low-power standby states. | Select SN74LS27N if system clock rates < 10 MHz and static power minimization is prioritized over speed. |
| SN74F27N | Faster switching (tPHL/tPLH = 2.5/3.5 ns typ), higher ICC (5–8 mA), same pinout and logic function. | High-frequency control planes requiring sub-5 ns decision latency, such as video sync generators or fast interrupt arbiters. | Choose SN74F27N when propagation delay budget is < 4 ns and supply current overhead is acceptable. |
Compared with SN74LS27N and SN74F27N, the DM74ALS27N delivers optimal balance: 3–4 ns typical delays rival F-series speed while maintaining ALS-family power efficiency (ICC ≈ 2–4 mA at outputs LOW), making it ideal for mid-speed industrial controllers where thermal density and timing predictability are both critical.
Availability
DM74ALS27N is available at Aetrix Electronics and suitable for address decoding, bus arbitration, control signal generation, and reset logic conditioning requiring stable component supply and long-term industrial availability.
Supply support for DM74ALS27N includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Fairchild Semiconductor was a U.S.-based designer and manufacturer of analog and mixed-signal semiconductors, acquired by ON Semiconductor in 2016; known for industry-standard logic, power, and interface ICs.
The DM74ALS27N belongs to Fairchild's Advanced Low-Power Schottky (ALS) TTL logic family, engineered for improved speed-power trade-offs in commercial-grade digital systems where reliability and pin compatibility with legacy TTL were essential.
FAQ
What logic function does the DM74ALS27N implement?
The DM74ALS27N implements three independent 3-input NOR gates. For each gate, the output is HIGH only when all three inputs are LOW; otherwise, the output is LOW. This matches the Boolean expression Y = NOT(A OR B OR C). The DM74ALS27N performs this function across all three gates simultaneously with no internal interdependence.
Is the DM74ALS27N pin-compatible with other 74-series NOR gates?
Yes, the DM74ALS27N is pin-for-pin compatible with the 74S27 and 74LS27 in the 14-lead PDIP package. Pin assignments for inputs, outputs, VCC, and GND match exactly, enabling direct substitution in existing layouts without PCB modification - confirmed by Fairchild's official connection diagram and ordering documentation.
What are the absolute maximum ratings for the DM74ALS27N?
The DM74ALS27N has an absolute maximum supply voltage of 7 V, input voltage limit of 7 V, operating free-air temperature range of 0°C to +70°C, and storage temperature range of −65°C to +150°C. Exceeding any of these values may cause permanent device damage, and operation outside recommended conditions voids parametric guarantees.
Can the DM74ALS27N drive standard TTL loads directly?
Yes, the DM74ALS27N can drive up to 10 standard TTL unit loads directly. Its IOL rating of 8 mA and IOH rating of −0.4 mA meet or exceed the input current requirements of legacy 74-series TTL inputs, eliminating the need for external buffer stages in most medium-density logic designs using the DM74ALS27N.
Does the DM74ALS27N require external pull-up resistors on its outputs?
No, the DM74ALS27N does not require external pull-up resistors. Its outputs are totem-pole (push-pull) configured, capable of actively driving both HIGH and LOW logic levels. Pull-ups are unnecessary unless interfacing with open-collector systems - a configuration not supported by the DM74ALS27N's internal output structure.
DM74ALS27N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ALS
- Package/Case:
- 14-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- NOR Gate
- Number of Circuits:
- 3
- Number of Inputs:
- 3
- Features:
- -
- Voltage - Supply:
- 4.5V ~ 5.5V
- Current - Quiescent (Max):
- -
- Current - Output High, Low:
- 400µA, 8mA
- Input Logic Level - Low:
- 0.8V
- Input Logic Level - High:
- 2V
- Max Propagation Delay @ V, Max CL:
- 15ns @ 5V, 50pF
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 14-MDIP
DM74ALS27N FAQ
1.How can I place an order for DM74ALS27N through Aetrix?
Please submit a Request for Quotation (RFQ) for DM74ALS27N on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for DM74ALS27N reliable?
The price and inventory of DM74ALS27N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DM74ALS27N is usually 5 days.
3.What payment methods are accepted for DM74ALS27N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DM74ALS27N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DM74ALS27N?
DM74ALS27N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DM74ALS27N order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for DM74ALS27N?
For technical support, including DM74ALS27N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DM74ALS27N requirements.
6.How does Aetrix verify that DM74ALS27N is sourced from the original manufacturer or authorized distributors?
All DM74ALS27N products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that DM74ALS27N meets industry standards.
7.What is the process for return or replacement of DM74ALS27N?
All DM74ALS27N units undergo pre-shipment inspection (PSI). If there is an issue with DM74ALS27N, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The DM74ALS27N part is unused and in its original packaging.
Return procedure for DM74ALS27N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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