My Inquiry
My Account
onsemi DM74ALS21AM
- Part No.:
- DM74ALS21AM
- Manufacturer:
- onsemi
- Category:
- Gates and Inverters
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
DM74ALS21AM.pdf
- Description:
- IC GATE AND 2CH 4-INP 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,300
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
DM74ALS21AM 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 tPLH ≤ 15 ns and tPHL ≤ 10 ns at CL = 50 pF, used for combinational logic in industrial control panels and digital instrumentation signal conditioning.
For engineers reviewing the DM74ALS21AM datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed AC performance over 0°C to +70°C, TTL-compatible input thresholds (VIL = 0.8 V, VIH = 2.0 V), and output drive capability (IOL = 8 mA, IOH = –0.4 mA) in a JEDEC MS-012 narrow-body SOIC.
Technical Context
The DM74ALS21AM implements two independent 4-input AND functions using advanced oxide-isolated, ion-implanted Schottky TTL process. It guarantees switching specifications across full temperature (0°C to +70°C) and supply voltage (4.5–5.5 V) ranges, with propagation delays specified at RL = 500 Ω and CL = 50 pF.
Its logic behavior follows Y = A·B·C·D per gate, with defined HIGH/LOW input voltage thresholds (VIH = 2.0 V min, VIL = 0.8 V max) and rail-referenced output levels (VOH ≥ VCC – 2 V, VOL ≤ 0.5 V at IOL = 8 mA), ensuring interoperability with standard TTL families.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - supports standard 5 V TTL power rails with ±10% tolerance |
| tPLH / tPHL | 4–15 ns / 2–10 ns - enables high-speed combinational logic in clocked systems up to ~50 MHz |
| IOL / IOH | 8 mA / –0.4 mA - drives standard TTL loads without external buffers |
| VIL / VIH | 0.8 V / 2.0 V - ensures noise margin compatibility with legacy TTL and LS-TTL inputs |
| Operating Temp | 0°C to +70°C - rated for commercial-grade industrial equipment environments |
| Input Clamp Voltage | –1.5 V - protects against negative transients during hot insertion or ESD events |
Pinout & Package
DM74ALS21AM is housed in a 14-lead Small Outline Integrated Circuit (SOIC) package, JEDEC MS-012 compliant, 0.150" narrow body, with 1.27 mm lead pitch and thermal resistance θJA = 116.0°C/W.
| 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 Y1 to assert |
| 5 | Gate 1 Output (Y1) | Active-HIGH open-collector compatible output; sinks up to 8 mA |
| 6, 7, 8, 9 | Gate 2 Inputs (A–D) | Four logic inputs for second independent AND gate |
| 10 | Gate 2 Output (Y2) | Second independent active-HIGH output with identical drive specs as Y1 |
| 14 | VCC | Positive supply terminal; must be decoupled locally for stable AC operation |
| 7 | GND | Ground reference for both gates; shared return path for all inputs and outputs |
Key Features
| Feature | Design Value |
|---|---|
| Functionally and pin-for-pin compatible with 74S21 and 74LS21 | Enables drop-in replacement in existing S-TTL and LS-TTL designs without layout change |
| Guaranteed switching specs at 50 pF load | Ensures predictable timing behavior in real-world PCB traces and fanout scenarios |
| Advanced oxide-isolated Schottky TTL process | Delivers improved speed-power trade-off vs. standard Schottky TTL, with lower ICC (0.85–1.4 mA) |
| Full temperature and VCC range qualification | Validates reliable operation across entire commercial temperature and supply envelope |
Applications
| Industrial Control Logic | Digital Instrumentation |
|---|---|
Use Scenario: Interlocking safety conditions in PLC-based motor control cabinets where four sensor signals must all be asserted before enabling actuator output. IC Role / Device Role: Dual 4-input AND gate performing real-time hardware-level enable validation prior to microcontroller intervention. Use Value: Provides deterministic, zero-latency logic gating with no firmware dependency or interrupt latency. | Use Scenario: Signal qualification in benchtop multimeters requiring simultaneous presence of range select, function select, autorange lock, and calibration mode signals. IC Role / Device Role: Hardware AND gate generating internal "valid configuration" flag used to gate ADC sampling and display update. Use Value: Eliminates software polling overhead and ensures measurement integrity under transient configuration changes. |
| Legacy System Repair | Test Equipment Interface |
Use Scenario: Replacing obsolete 74S21 or 74LS21 in vintage test gear where board space and pinout are fixed. IC Role / Device Role: Pin-compatible TTL logic replacement preserving original timing and loading characteristics. Use Value: Restores functionality without redesign, leveraging identical SOIC footprint and DC/AC specs. | Use Scenario: Enabling GPIB or RS-232 handshake signals only when multiple readiness flags (BUSY, READY, LOCAL, REMOTE) are concurrently active. IC Role / Device Role: Combinatorial enable generator for serial interface state machines in automated test systems. Use Value: Reduces FPGA or microcontroller I/O count by offloading synchronous multi-signal arbitration to dedicated logic. |
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 and pinout; higher θJA (120°C/W), no surface-mount option | Suitable for through-hole prototyping or legacy DIP-based systems; not for automated SMT assembly | Select SN74ALS21N only when PDIP mounting or socketing is required |
| 74F21PC | Fast TTL family: faster tPLH/tPHL (3.5/2.5 ns typ), higher ICC (12 mA), tighter VIH/VIL (2.0/0.8 V same), but higher power consumption | Better for high-frequency clocked logic; less suitable for low-power or thermally constrained designs | Choose 74F21PC only when sub-10 ns propagation is mandatory and power budget allows |
Compared with SN74ALS21N and 74F21PC, the DM74ALS21AM offers optimal balance of surface-mount compatibility, thermal performance (θJA = 116°C/W), and proven reliability in commercial-temperature industrial control, while maintaining full functional and pin compatibility with legacy 74S/74LS designs.
Availability
DM74ALS21AM is available at Aetrix Electronics and suitable for industrial control logic, digital instrumentation, legacy system repair, and test equipment interface applications requiring stable component supply and long-term obsolescence management.
Supply support for DM74ALS21AM 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 devices before its acquisition by ON Semiconductor in 2016.
The DM74ALS21AM belongs to Fairchild's Advanced Low-Power Schottky (ALS) TTL logic family, designed for high-speed, low-power digital systems requiring compatibility with legacy TTL architectures.
FAQ
What logic family does the DM74ALS21AM belong to?
The DM74ALS21AM belongs to the Advanced Low-Power Schottky (ALS) TTL logic family. It uses oxide-isolated, ion-implanted Schottky technology to achieve better speed-power trade-offs than standard Schottky (S) or Low-Power Schottky (LS) TTL. The DM74ALS21AM maintains full DC and AC compatibility with those families while offering improved propagation delay and reduced supply current.
Is the DM74ALS21AM pin-compatible with the 74LS21 and 74S21?
Yes, the DM74ALS21AM is functionally and pin-for-pin compatible with both the 74LS21 and 74S21. Its pinout matches the standard 14-lead dual 4-input AND gate configuration: 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 replacement in existing designs without PCB modification.
What is the maximum capacitive load the DM74ALS21AM can drive while meeting timing specs?
The DM74ALS21AM switching characteristics-including tPLH ≤ 15 ns and tPHL ≤ 10 ns-are guaranteed at CL = 50 pF. While it may drive larger loads, timing margins degrade beyond this value. For reliable operation within datasheet limits, keep total output node capacitance (including trace, stub, and input capacitance of driven devices) at or below 50 pF, especially in high-speed or noise-sensitive applications.
Does the DM74ALS21AM support operation at 3.3 V?
No, the DM74ALS21AM is not rated for 3.3 V operation. Its recommended VCC range is strictly 4.5 V to 5.5 V, and absolute maximum VCC is 7 V. Operating below 4.5 V risks undefined logic thresholds, increased propagation delay, and potential failure to meet VOH/VOL specifications. For 3.3 V systems, consider modern CMOS alternatives like 74LVC21A.
What is the thermal resistance (θJA) of the DM74ALS21AM in its SOIC package?
The DM74ALS21AM in the M14A SOIC package has a typical junction-to-ambient thermal resistance (θJA) of 116.0°C/W. This value assumes standard JEDEC test conditions (single-layer board, no copper pour). Actual thermal performance improves significantly with PCB copper area, thermal vias, and airflow-critical for sustained operation near maximum ICC (2.3 mA) in enclosed enclosures.
DM74ALS21AM Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ALS
- Package/Case:
- 14-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- 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
DM74ALS21AM FAQ
1.How can I place an order for DM74ALS21AM through Aetrix?
Please submit a Request for Quotation (RFQ) for DM74ALS21AM 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 DM74ALS21AM reliable?
The price and inventory of DM74ALS21AM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DM74ALS21AM is usually 5 days.
3.What payment methods are accepted for DM74ALS21AM?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DM74ALS21AM transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DM74ALS21AM?
DM74ALS21AM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DM74ALS21AM 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 DM74ALS21AM?
For technical support, including DM74ALS21AM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DM74ALS21AM requirements.
6.How does Aetrix verify that DM74ALS21AM is sourced from the original manufacturer or authorized distributors?
All DM74ALS21AM 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 DM74ALS21AM meets industry standards.
7.What is the process for return or replacement of DM74ALS21AM?
All DM74ALS21AM units undergo pre-shipment inspection (PSI). If there is an issue with DM74ALS21AM, 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 DM74ALS21AM part is unused and in its original packaging.
Return procedure for DM74ALS21AM:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
DM74ALS21AM Tags
-
SN74LVC1G14DBVR
Texas Instruments
-
SN74LVC1G14DCKR
Texas Instruments
-
SN74AHC1G14DBVR
Texas Instruments
-
SN74LVC1G08DBVR
Texas Instruments
-
SN74LVC1G08DCKR
Texas Instruments
-
SN74LVC1G32DCKR
Texas Instruments
-
SN74LVC1G04DBVR
Texas Instruments
.jpg)
-
74LVC1G08GW,125
Nexperia USA Inc.
-
SN74LVC1G04DCKR
Texas Instruments
-
SN74AHC1G08DBVR
Texas Instruments
-
SN74LVC1G32DBVR
Texas Instruments
-
SN74AHCT1G08DBVR
Texas Instruments
Tech Hub
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
