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onsemi DM74ALS540AWMX
- Part No.:
- DM74ALS540AWMX
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
DM74ALS540AWMX.pdf
- Description:
- IC BUFFER INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,729
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Product details
Overview
DM74ALS540AWMX 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 ≤ 12/9 ns, and IOL = 24 mA drive capability. It serves as a bidirectional bus interface or address/data latch driver in TTL-based microprocessor systems.
For engineers reviewing the DM74ALS540AWMX 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, 24 mA IOL, and compatibility with ALS-level TTL voltage thresholds.
Technical Context
The DM74ALS540AWMX 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).
Propagation delays are characterized under R1=R2=500 Ω, CL=50 pF: tPLH ≤ 12 ns, tPHL ≤ 9 ns, tPZH ≤ 15 ns, and tPLZ ≤ 12 ns. Input clamp voltage (VIK) is −1.5 V at II = −18 mA, and P-N-P inputs reduce DC loading versus standard TTL.
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 noise margin stability |
| IOH / IOL | −15 mA / 24 mA - Supports direct driving of multiple TTL loads or termination-resistor networks |
| tPLH / tPHL | ≤12 ns / ≤9 ns - Enables reliable operation in 25 MHz+ address/data bus timing paths |
| VIH / VIL | ≥2.0 V / ≤0.7 V - Matches ALS-TTL input thresholds for clean interfacing with 74ALS logic families |
| 3-STATE Enable Logic | G1 OR G2 HIGH → all Y outputs Hi-Z - Dual-enable NOR gate allows flexible bus arbitration control |
| θJA (SOIC) | 77.5 °C/W - Defines thermal derating for continuous operation at ambient up to +70°C |
| Operating Temperature | 0°C to +70°C - Specifies commercial-grade ambient range for industrial control and computing applications |
Pinout & Package
DM74ALS540AWMX is housed in a 20-lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" wide (Package Number M20B). The package supports surface-mount assembly and provides enhanced PCB layout via data flow-thru pinout: all inputs on one side, all outputs on the opposite side.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | Input A1–A8 | Inverting data inputs; accept standard ALS-TTL logic levels (VIL ≤ 0.7 V, VIH ≥ 2.0 V) |
| 9, 10, 11, 12, 13, 14, 15, 16 | Output Y1–Y8 | Inverted buffered outputs; drive up to 24 mA low or −15 mA high in active state |
| 19, 20 | G1, G2 | 3-STATE enable inputs; NOR logic - either HIGH forces all Yn into high-impedance state |
| 10 | GND | Ground reference for all internal circuitry and output drivers |
| 20 | VCC | Positive supply terminal; must be decoupled locally for noise-sensitive bus applications |
Key Features
| Feature | Design Value |
|---|---|
| Data flow-thru pinout | Inputs (pins 1–8) and outputs (pins 9–16) on opposite package edges - simplifies routing and reduces crosstalk on dense PCBs |
| P-N-P input structure | Reduces input DC loading to ≤ ±100 µA - lowers power consumption and eases fanout in large bus systems |
| Guaranteed AC specs over full range | tPLH/tPHL ≤ 12/9 ns at VCC = 4.5–5.5 V and TA = 0–70°C - eliminates need for derating in commercial environments |
| Advanced Schottky TTL process | Oxide-isolated, ion-implanted fabrication - improves noise immunity and long-term reliability vs. standard TTL |
| 3-STATE dual-enable NOR gate | G1 and G2 inputs share single NOR logic function - enables priority-based bus control or redundant enable paths |
Applications
| Microprocessor Address Bus Driver | TTL-to-TTL Bus Isolation |
|---|---|
Use Scenario: Driving 16-bit address lines from a microprocessor to memory or peripheral chips with load matching and noise isolation. IC Role / Device Role / Timing Role: Inverting buffer with 3-STATE control acts as address latch driver; enables/disables bus segments during DMA cycles. Use Value: 24 mA sink current ensures fast low-to-high transitions into capacitive bus loads; tPHL ≤ 9 ns meets 25 MHz bus timing budgets. | Use Scenario: Isolating two TTL subsystems sharing a common data bus while preventing contention during read/write handshaking. IC Role / Device Role / Timing Role: Octal inverting buffer with dual-enable 3-STATE provides direction-controlled bidirectional isolation between master and slave buses. Use Value: Data flow-thru pinout minimizes trace length mismatch; G1/G2 NOR logic allows coordinated enable/disable with handshake signals. |
| Industrial PLC I/O Expansion Module | Legacy Computer Backplane Interface |
Use Scenario: Interfacing microcontroller GPIOs to relay driver arrays or opto-isolator inputs in programmable logic controller modules. IC Role / Device Role / Timing Role: Level-shifting and current-boosting buffer; converts low-drive MCU outputs to robust TTL-compatible signals. Use Value: −15 mA/24 mA drive capability directly drives optocoupler LEDs or small-signal relays without external transistors. | Use Scenario: Adapting vintage CPU boards (e.g., Z80, 8085) to modern backplane designs requiring controlled bus release and signal integrity. IC Role / Device Role / Timing Role: Inverting line driver with precise 3-STATE timing (tPZL ≤ 20 ns, tPLZ ≤ 12 ns) ensures glitch-free bus handoff during cycle stealing. Use Value: Guaranteed tPLZ/tPHZ specs prevent bus contention during state transitions; SOIC package supports rework-friendly SMT assembly. |
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 family, identical logic and AC specs, but in PDIP (N20A) package - no thermal resistance advantage | Through-hole assembly only; unsuitable for high-density SMT layouts | Select when legacy through-hole prototyping or repair of vintage systems is required |
| 74F540PC | Fast TTL variant: faster tPLH/tPHL (≤ 6.5 ns), higher ICC (up to 30 mA), wider VCC tolerance (4.5–5.5 V), but higher power and lower noise margin | Higher-speed bus applications where ALS timing margins are insufficient | Select when sub-10 ns propagation is mandatory and power budget allows ~2× ICC increase |
Compared with SN74ALS540N and 74F540PC, the DM74ALS540AWMX offers optimal balance of speed (≤12 ns), power efficiency (ICC ≤ 22 mA), and SMT-ready SOIC packaging - making it preferred for new industrial control and embedded computing designs requiring proven ALS reliability.
Availability
DM74ALS540AWMX is available at Aetrix Electronics and suitable for industrial PLC I/O modules, microprocessor address bus interfaces, and legacy computer backplane upgrades requiring stable component supply, long-lifecycle support, and RoHS-compliant sourcing.
Supply support for DM74ALS540AWMX 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 and manufacturer of analog and mixed-signal ICs, power management devices, and logic families before its acquisition by ON Semiconductor in 2016.
The DM74ALS540AWMX belongs to Fairchild's advanced low-power Schottky (ALS) TTL logic series, engineered for high-speed, low-power bus interface and data latching in commercial-grade computing and industrial control systems.
FAQ
What is the logic function of the DM74ALS540AWMX?
The DM74ALS540AWMX performs octal inverting buffering with 3-STATE outputs. Each of its eight channels accepts a logic input (A1–A8), inverts it, and delivers the result at the corresponding output (Y1–Y8) when enabled. The G1 and G2 pins form a NOR gate: if either is HIGH, all outputs enter high-impedance mode. This behavior is fully documented in the device's function table and confirmed across all operating conditions.
Does the DM74ALS540AWMX support 3.3 V logic interfacing?
No, the DM74ALS540AWMX is designed exclusively for 5 V TTL operation. Its VCC range is 4.5–5.5 V, VIH minimum is 2.0 V, and VIL maximum is 0.7 V - all aligned with ALS-TTL thresholds. Direct connection to 3.3 V logic requires level-shifting circuitry, as the device lacks 3.3 V tolerant inputs or outputs. The DM74ALS540AWMX does not specify or guarantee operation below 4.5 V.
What is the thermal resistance (θJA) of the DM74ALS540AWMX package?
For the DM74ALS540AWMX in its 20-lead SOIC (M20B) package, the typical junction-to-ambient thermal resistance (θJA) is 77.5 °C/W, as specified in the Absolute Maximum Ratings section of the official Fairchild datasheet DS009170. This value assumes standard JEDEC test board conditions and guides thermal design for continuous operation within the 0°C to +70°C ambient range.
How does the DM74ALS540AWMX differ from the non-A version (DM74ALS540WMX)?
The DM74ALS540AWMX includes improved AC and DC specifications over the original DM74ALS540WMX, including tighter propagation delay limits (tPLH ≤ 12 ns vs. unspecified earlier), guaranteed performance across full VCC and temperature ranges, and updated electrical characteristics such as VOH/VOL and IIL/IIH. The "A" suffix denotes the revised, fully characterized revision released in the February 2000 datasheet revision.
Can the DM74ALS540AWMX replace the DM74ALS240A in existing designs?
Yes - the DM74ALS540AWMX is functionally compatible with the DM74ALS240A as both are octal inverting buffers with 3-STATE outputs and identical pinouts (20-pin SOIC, PDIP, SOP). However, the DM74ALS540AWMX features the data flow-thru arrangement (inputs/outputs on opposite sides), whereas the DM74ALS240A uses a different pin mapping. Physical replacement requires verifying PCB layout alignment; the DM74ALS540AWMX is not a drop-in mechanical substitute without board revision.
DM74ALS540AWMX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ALS
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- 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
DM74ALS540AWMX FAQ
1.How can I place an order for DM74ALS540AWMX through Aetrix?
Please submit a Request for Quotation (RFQ) for DM74ALS540AWMX 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 DM74ALS540AWMX reliable?
The price and inventory of DM74ALS540AWMX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DM74ALS540AWMX is usually 5 days.
3.What payment methods are accepted for DM74ALS540AWMX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DM74ALS540AWMX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DM74ALS540AWMX?
DM74ALS540AWMX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DM74ALS540AWMX 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 DM74ALS540AWMX?
For technical support, including DM74ALS540AWMX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DM74ALS540AWMX requirements.
6.How does Aetrix verify that DM74ALS540AWMX is sourced from the original manufacturer or authorized distributors?
All DM74ALS540AWMX 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 DM74ALS540AWMX meets industry standards.
7.What is the process for return or replacement of DM74ALS540AWMX?
All DM74ALS540AWMX units undergo pre-shipment inspection (PSI). If there is an issue with DM74ALS540AWMX, 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 DM74ALS540AWMX part is unused and in its original packaging.
Return procedure for DM74ALS540AWMX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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