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onsemi DM74ALS540AWM
- Part No.:
- DM74ALS540AWM
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
DM74ALS540AWM.pdf
- Description:
- IC BUFFER INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,651
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Product details
Overview
DM74ALS540AWM from Fairchild Semiconductor is an octal inverting buffer and line driver with 3-STATE outputs in a 20-lead SOIC (M20B) package, featuring guaranteed switching performance from 0°C to +70°C, VCC = 4.5–5.5 V, tPLH/tPHL ≤ 12 ns, and IOL = 24 mA drive capability. It serves as a bidirectional bus interface or address/data latch driver in TTL-level microprocessor systems.
For engineers reviewing the DM74ALS540AWM datasheet, pinout, applications, or equivalent options, key selection criteria include its data flow-thru pinout (inputs/outputs on opposite sides), dual 3-STATE enable (G1/G2 NOR logic), −15 mA IOH, and compatibility with ALS TTL logic families in industrial control and legacy computing backplanes.
Technical Context
The DM74ALS540AWM implements eight independent inverting buffers, each with high-current sinking (24 mA) and sourcing (−15 mA) capability, and a shared 2-input NOR gate controlling all outputs' 3-STATE state. Its oxide-isolated, ion-implanted Schottky TTL process ensures stable operation across full VCC (4.5–5.5 V) and temperature (0°C to +70°C) ranges.
Propagation delays are tightly specified: tPLH/tPHL ≤ 12 ns (A/B to Y), tPZH ≤ 15 ns, and tPLZ ≤ 12 ns (G to Y), with input clamp voltage VIK = −1.5 V and P-N-P inputs minimizing DC loading on driving sources.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - Ensures compatibility with standard 5 V TTL supply rails and noise margin stability |
| IOH / IOL | −15 mA / 24 mA - Supports direct interfacing to multiple TTL loads without external buffering |
| tPLH / tPHL | 2 ns (min) to 12 ns (max) - Enables reliable operation in 80 MHz-equivalent bus timing windows |
| VIH / VIL | 2.0 V / 0.7 V - Matches standard TTL input thresholds for seamless integration into ALS/TTL systems |
| Operating Temp | 0°C to +70°C - Qualified for commercial-grade embedded control and instrumentation applications |
| 3-STATE Enable | G1 NOR G2 logic - Allows flexible bus arbitration using either or both enables; Hi-Z on any HIGH input |
| θJA (SOIC) | 77.5°C/W - Defines thermal derating limits for continuous 24 mA output loading in PCB layouts |
Pinout & Package
DM74ALS540AWM is housed in a 20-lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" wide (Package Number M20B), with gull-wing leads and 0.050" pitch. The data flow-thru layout places all eight inputs (A1–A8) on one side and all eight inverted outputs (Y1–Y8) on the opposite side, simplifying PCB routing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | A1–A8 Inputs | Inverting data inputs; accept standard TTL logic levels (VIH ≥ 2.0 V, VIL ≤ 0.7 V) |
| 9 | G1 | First 3-STATE enable input; HIGH forces all Y outputs into high-impedance state |
| 10 | G2 | Second 3-STATE enable input; HIGH (with G1) forces all Y outputs into high-impedance state |
| 11, 13, 14, 15, 16, 17, 18, 19 | Y1–Y8 Outputs | Inverted, 3-STATE outputs; sink up to 24 mA or source up to −15 mA when enabled |
| 12 | GND | Ground reference for logic and output stages |
| 20 | VCC | Positive supply terminal (4.5–5.5 V); powers internal logic and output drivers |
Key Features
| Feature | Design Value |
|---|---|
| Data flow-thru pinout | Inputs (pins 1–8) and outputs (pins 11,13–19) on opposite package edges - reduces trace crossovers and improves signal integrity in dense PCBs |
| Dual 3-STATE enable (G1/G2) | NOR-gated control allows independent bus arbitration via either enable or combined logic - supports multi-master system design |
| P-N-P input structure | Reduces DC input current (IIL = −100 µA max) - lowers loading on upstream drivers and improves fanout in cascaded TTL chains |
| ALS-compatible performance | Guaranteed timing and drive specs over full VCC and temperature range - ensures drop-in replacement for DM74ALS240A in legacy designs |
Applications
| Microprocessor Address Bus Driver | Industrial PLC I/O Expansion Module |
|---|---|
Use Scenario: Driving 8-bit address lines from a microprocessor to memory or peripheral chips in a 5 V TTL system. IC Role / Device Role / Timing Role: Inverting buffer with 3-STATE control; isolates address bus during DMA cycles or peripheral access. Use Value: 24 mA sink capability ensures clean low-level transitions across long traces; tPHL ≤ 9 ns meets 8085/8088 bus timing requirements. | Use Scenario: Interfacing discrete sensor inputs to a programmable logic controller's central backplane. IC Role / Device Role / Timing Role: Level-shifting and bus-isolating buffer; enables hot-swap of I/O modules without disrupting main CPU bus. Use Value: Dual G1/G2 enables allow module-specific bus gating; P-N-P inputs minimize loading on optocoupler outputs. |
| Legacy Computer Backplane Interface | TTL Logic Test Fixture |
Use Scenario: Buffering and inverting control signals (e.g., RD, WR, IORQ) across a multi-slot ISA-style backplane. IC Role / Device Role / Timing Role: Octal inverting line driver with 3-STATE; provides impedance matching and noise immunity on shared bus lines. Use Value: 12 ns max propagation delay preserves setup/hold margins; SOIC package fits high-density backplane layouts. | Use Scenario: Generating and monitoring controlled logic patterns during IC validation or board-level functional test. IC Role / Device Role / Timing Role: Programmable stimulus/response node; outputs driven by pattern generator, inputs monitored by logic analyzer. Use Value: Hi-Z state enables safe floating-bus testing; guaranteed VIK = −1.5 V protects against tester-induced negative transients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer with 3-STATE applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS540N | Same ALS logic family, identical pinout and electrical specs; PDIP package (N20A) instead of SOIC | Preferred for through-hole prototyping or legacy repair where SOIC rework is impractical | Select SN74ALS540N when manual soldering or socket-based debugging is required |
| MC74ACT540DW | Advanced CMOS (ACT) family; 4.5–5.5 V supply, but faster (tPD ≤ 8 ns), lower ICC (5 mA), and higher noise immunity (VIH = 3.5 V) | Requires level translation if interfacing with older TTL-only systems due to higher VIH threshold | Select MC74ACT540DW for new designs needing lower power and higher speed, with compatible logic family infrastructure |
Compared with SN74ALS540N and MC74ACT540DW, the DM74ALS540AWM offers proven SOIC reliability in space-constrained industrial backplanes, retains full ALS TTL compatibility without level shifters, and delivers deterministic 3-STATE timing critical for synchronous bus arbitration.
Availability
DM74ALS540AWM is available at Aetrix Electronics and suitable for industrial control systems, legacy computer refurbishment, and embedded instrumentation requiring stable component supply and long-term obsolescence management.
Supply support for DM74ALS540AWM 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 leading designer of analog and mixed-signal semiconductors, acquired by ON Semiconductor in 2016; its legacy logic portfolio remains widely deployed in industrial and computing infrastructure.
The DM74ALS540AWM belongs to Fairchild's advanced low-power Schottky (ALS) TTL logic family, engineered for high-speed, low-power bus interfacing in commercial-grade microprocessor and control systems.
FAQ
What logic family does the DM74ALS540AWM belong to, and is it compatible with standard TTL?
The DM74ALS540AWM belongs to the Advanced Low-Power Schottky (ALS) TTL logic family. It is fully compatible with standard TTL in terms of voltage thresholds (VIH = 2.0 V, VIL = 0.7 V), drive strength, and timing. The DM74ALS540AWM maintains pin- and function-compatibility with earlier 74LS and 74ALS series octal buffers, making it a direct replacement in existing TTL designs without circuit modification.
Does the DM74ALS540AWM support simultaneous 3-STATE control of all outputs, and how is it implemented?
Yes, the DM74ALS540AWM supports simultaneous 3-STATE control via a dual-input NOR gate formed by G1 and G2 pins. If either G1 or G2 is HIGH, all eight Y outputs enter high-impedance (Hi-Z) state. This architecture allows flexible bus arbitration - for example, G1 can be used for system-wide disable while G2 enables local module control. The DM74ALS540AWM's NOR-based enable ensures predictable, race-free bus release.
What is the maximum output current specification for the DM74ALS540AWM, and how does it impact load driving capability?
The DM74ALS540AWM specifies IOL = 24 mA (sink) and IOH = −15 mA (source) under recommended operating conditions. This allows each output to directly drive up to 10 standard TTL inputs (fanout of 10) or terminate unterminated transmission lines in backplane applications. The DM74ALS540AWM's robust drive strength eliminates need for external pull-ups or buffer stages in most 5 V TTL interconnect scenarios.
Is the DM74ALS540AWM available in other packages, and how does the SOIC version differ mechanically?
Yes, the DM74ALS540AWM is the SOIC variant (Package M20B); other versions include DM74ALS540AN (PDIP, N20A) and DM74ALS540ASJ (SOP, M20D). The DM74ALS540AWM uses JEDEC MS-013 SOIC with 0.300" body width and gull-wing leads. Its data flow-thru layout - inputs on one side, outputs on the opposite - reduces PCB layer count and improves routing efficiency compared to symmetrical DIP layouts.
What thermal considerations apply to the DM74ALS540AWM in continuous operation?
The DM74ALS540AWM has a junction-to-ambient thermal resistance θJA of 77.5°C/W in its SOIC package. At maximum rated output current (24 mA per output, all active), power dissipation reaches ~110 mW, resulting in ~8.5°C junction rise above ambient. For sustained operation near 70°C ambient, derating is minimal; however, airflow or copper pour is recommended if multiple devices operate simultaneously in enclosed enclosures. The DM74ALS540AWM's thermal profile supports reliable use in fanless industrial controllers.
DM74ALS540AWM Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ALS
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 15mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
DM74ALS540AWM FAQ
1.How can I place an order for DM74ALS540AWM through Aetrix?
Please submit a Request for Quotation (RFQ) for DM74ALS540AWM 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 DM74ALS540AWM reliable?
The price and inventory of DM74ALS540AWM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DM74ALS540AWM is usually 5 days.
3.What payment methods are accepted for DM74ALS540AWM?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DM74ALS540AWM transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DM74ALS540AWM?
DM74ALS540AWM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DM74ALS540AWM 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 DM74ALS540AWM?
For technical support, including DM74ALS540AWM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DM74ALS540AWM requirements.
6.How does Aetrix verify that DM74ALS540AWM is sourced from the original manufacturer or authorized distributors?
All DM74ALS540AWM 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 DM74ALS540AWM meets industry standards.
7.What is the process for return or replacement of DM74ALS540AWM?
All DM74ALS540AWM units undergo pre-shipment inspection (PSI). If there is an issue with DM74ALS540AWM, 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 DM74ALS540AWM part is unused and in its original packaging.
Return procedure for DM74ALS540AWM:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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