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onsemi DM74ALS21AMX
- Part No.:
- DM74ALS21AMX
- Manufacturer:
- onsemi
- Category:
- Gates and Inverters
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
DM74ALS21AMX.pdf
- Description:
- IC GATE AND 2CH 4-INP 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,395
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Product details
Overview
DM74ALS21AMX from Fairchild Semiconductor is a dual 4-input AND gate IC in 14-lead SOIC (M14A) package, operating at VCC = 4.5–5.5 V with propagation delays as low as 2 ns (tPHL typ) and 4 ns (tPLH min), delivering TTL-compatible logic for digital control subsystems in industrial controllers and instrumentation.
For engineers reviewing the DM74ALS21AMX datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed AC performance over 0°C to +70°C, 8 mA sink capability (IOL), 0.35 V VOL at 8 mA, and functional/pin compatibility with standard Schottky TTL families.
Technical Context
The DM74ALS21AMX implements two independent 4-input AND gates using advanced oxide-isolated, ion-implanted Schottky TTL process, ensuring stable DC and AC operation across full temperature and supply voltage ranges. Each gate outputs HIGH only when all four inputs (A–D) are HIGH, per Y = ABCD logic function.
It meets switching specifications at 50 pF load, supports 500 Ω load resistance, and delivers rail-to-rail compatible output drive - VOH ≥ VCC – 2 V and VOL ≤ 0.5 V - enabling direct interfacing with legacy TTL and LSTTL systems without level-shifting.
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 | 2–10 ns / 4–15 ns - enables high-speed combinational logic in clocked state machines and address decoding. |
| IOL / IOH | 8 mA / –0.4 mA - supports driving multiple TTL inputs (fan-out ≥ 20) or small LED indicators directly. |
| VOL / VOH | ≤0.5 V / ≥VCC–2 V - guarantees noise margins >0.4 V under worst-case loading, critical for reliable multi-gate cascading. |
| Operating Temp | 0°C to +70°C - validated for commercial-grade embedded control, not extended industrial or automotive. |
| Input Thresholds | VIL ≤ 0.8 V, VIH ≥ 2.0 V - matches standard TTL input sensitivity, eliminating need for external biasing. |
Pinout & Package
DM74ALS21AMX is housed in a 14-lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" narrow body (Package Number M14A), with 1.27 mm pitch and surface-mount footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4 | Gate 1 Inputs A–D | Four logic inputs for first AND gate; all must be HIGH for output (pin 5) to assert HIGH. |
| 5 | Gate 1 Output Y1 | Active-HIGH open-collector compatible output; sinks up to 8 mA at VOL ≤ 0.5 V. |
| 6, 7, 8, 9 | Gate 2 Inputs A–D | Four dedicated inputs for second independent AND gate; no shared internal nodes. |
| 10 | Gate 2 Output Y2 | Second independent AND output, electrically identical to pin 5, enabling parallel logic paths. |
| 14 | VCC | Positive supply terminal; decoupling capacitor required near pin for stable AC performance. |
| 7 | GND | Ground reference for both gates; common return path for all input/output currents. |
Key Features
| Feature | Design Value |
|---|---|
| Functionally & pin-compatible with 74S21/74LS21 | Enables drop-in replacement in legacy designs without PCB or firmware changes. |
| Guaranteed AC specs over full temp/VCC range | Eliminates derating calculations for timing-critical applications like synchronous bus arbitration. |
| Advanced Schottky TTL process | Reduces propagation delay variation vs. standard TTL while maintaining DC compatibility. |
| 50 pF switching characterization | Provides verified timing data for typical PCB trace and gate-load conditions, not just ideal lab loads. |
Applications
| Industrial PLC Logic Modules | Legacy Computer Bus Decoding |
|---|---|
Use Scenario: Implementing enable gating for I/O expansion slots in programmable logic controllers. IC Role / Device Role / Timing Role: Dual 4-input AND gate performing address-range validation before peripheral activation. Use Value: Simultaneous evaluation of 4-bit address segments with sub-15 ns delay ensures cycle-accurate bus handshaking. | Use Scenario: Generating chip-select signals for memory-mapped peripherals in 1980s–1990s microcomputer systems. IC Role / Device Role / Timing Role: Combinational logic element converting partial address bits into active-low device enables. Use Value: Guaranteed VOL ≤ 0.5 V and fan-out ≥20 allow direct drive of multiple 74-series inputs without buffers. |
| Test Equipment Signal Conditioning | Digital Panel Meter Input Gating |
Use Scenario: Synchronizing measurement triggers with external gate pulses in automated test equipment. IC Role / Device Role / Timing Role: AND gate combining internal sample clock and user-defined enable signal to control ADC sampling window. Use Value: 2 ns typical tPHL enables precise <10 ns pulse-width control, critical for jitter-sensitive sampling. | Use Scenario: Enabling display update only when valid sensor data and calibration flag are both asserted. IC Role / Device Role / Timing Role: Dual-gate logic block validating concurrent status flags before updating 7-segment driver. Use Value: Independent gate structure allows separate validation of analog front-end readiness and digital processing completion. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual 4-input AND gate applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS21N | Dual-in-line package (PDIP), same electrical specs, higher θJA (120°C/W), no tape-and-reel option. | Suitable for prototyping or through-hole assembly; less suitable for automated SMT production. | Select SN74ALS21N only when DIP footprint or hand-soldering is required. |
| MC74ALS21N | Identical logic and timing, but Motorola-branded; minor differences in ICC max (2.3 mA vs. 2.3 mA) and packaging (ceramic DIP). | Used in aerospace/military legacy systems where Motorola qualification is mandated. | Choose MC74ALS21N only if compliance with MIL-PRF-38535 or specific Motorola sourcing requirements applies. |
Compared with SN74ALS21N and MC74ALS21N, the DM74ALS21AMX offers optimized thermal performance (θJA = 116°C/W), SOIC packaging for space-constrained SMT layouts, and factory tape-and-reel delivery - making it the preferred choice for volume production of commercial-grade digital control boards.
Availability
DM74ALS21AMX is available at Aetrix Electronics and suitable for industrial PLC logic modules, legacy computer bus decoding, and digital panel meter input gating requiring stable component supply and long-term obsolescence management.
Supply support for DM74ALS21AMX 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 semiconductor company specializing in analog and mixed-signal ICs, power management, and logic families before its acquisition by ON Semiconductor in 2016.
The DM74ALS21AMX belongs to the 74ALS (Advanced Low-Power Schottky) logic family, designed to deliver improved speed-power trade-offs over standard TTL for commercial digital systems requiring reliable, pin-compatible upgrades.
FAQ
What logic family does the DM74ALS21AMX belong to?
The DM74ALS21AMX belongs to the 74ALS (Advanced Low-Power Schottky) TTL logic family. It uses oxide-isolated, ion-implanted Schottky technology to achieve faster switching than standard 74LS devices while maintaining lower power consumption than 74S series. The DM74ALS21AMX implements two independent 4-input AND functions with guaranteed performance across 0°C to +70°C and 4.5–5.5 V supply.
Is the DM74ALS21AMX pin-compatible with other 74-series dual 4-input AND gates?
Yes, the DM74ALS21AMX is functionally and pin-for-pin compatible with 74S21 and 74LS21 devices. Its pinout matches industry-standard 14-lead SOIC layout for dual 4-input AND gates: inputs on pins 1–4 and 6–9, outputs on pins 5 and 10, VCC on pin 14, and GND on pin 7. This allows direct substitution in existing designs without layout modification.
What is the maximum output sink current for the DM74ALS21AMX?
The DM74ALS21AMX guarantees a LOW-level output current (IOL) of 8 mA minimum at VOL ≤ 0.5 V, with VCC = 4.5 V. This enables reliable driving of up to 20 standard TTL inputs or discrete LEDs with appropriate current-limiting resistors. The specification is tested across the full operating temperature range (0°C to +70°C), ensuring consistent performance in real-world conditions.
Does the DM74ALS21AMX require external pull-up resistors on its outputs?
No, the DM74ALS21AMX features totem-pole (push-pull) outputs, not open-collector. Its outputs actively drive both HIGH and LOW states, so external pull-up resistors are unnecessary. The device delivers VOH ≥ VCC – 2 V and VOL ≤ 0.5 V under rated load, supporting direct interfacing with other TTL-family inputs without additional components.
What is the significance of the 'X' suffix in DM74ALS21AMX?
The 'X' suffix in DM74ALS21AMX indicates tape-and-reel packaging - specifically, the device is supplied in industry-standard 14-lead SOIC carrier tape compatible with automated SMT placement equipment. This distinguishes it from the tube-packaged DM74ALS21AM and ensures seamless integration into high-volume manufacturing workflows requiring consistent feeding and traceability.
DM74ALS21AMX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ALS
- Package/Case:
- 14-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Logic Type:
- AND Gate
- Number of Circuits:
- 2
- Number of Inputs:
- 4
- 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:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
DM74ALS21AMX FAQ
1.How can I place an order for DM74ALS21AMX through Aetrix?
Please submit a Request for Quotation (RFQ) for DM74ALS21AMX 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 DM74ALS21AMX reliable?
The price and inventory of DM74ALS21AMX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DM74ALS21AMX is usually 5 days.
3.What payment methods are accepted for DM74ALS21AMX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DM74ALS21AMX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DM74ALS21AMX?
DM74ALS21AMX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DM74ALS21AMX 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 DM74ALS21AMX?
For technical support, including DM74ALS21AMX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DM74ALS21AMX requirements.
6.How does Aetrix verify that DM74ALS21AMX is sourced from the original manufacturer or authorized distributors?
All DM74ALS21AMX 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 DM74ALS21AMX meets industry standards.
7.What is the process for return or replacement of DM74ALS21AMX?
All DM74ALS21AMX units undergo pre-shipment inspection (PSI). If there is an issue with DM74ALS21AMX, 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 DM74ALS21AMX part is unused and in its original packaging.
Return procedure for DM74ALS21AMX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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