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Texas Instruments CD74ACT540M
- Part No.:
- CD74ACT540M
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
CD74ACT540M.pdf
- Description:
- IC BUFF INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,080
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Product details
Overview
CD74ACT540M from Texas Instruments is an octal inverting 3-state buffer/line driver with dual active-low output enables, designed for high-speed digital bus interface and data routing in industrial control and instrumentation systems. It operates at 4.5V–5.5V, delivers ±24mA output drive, features balanced propagation delays (tPLH/tPHL ≤ 7.2ns at 5V), and supports 50Ω transmission-line driving.
For engineers reviewing the CD74ACT540M datasheet, CD74ACT540M pinout, CD74ACT540M application, or CD74ACT540M equivalent, key selection criteria include its ACT-series TTL-compatible input thresholds (VIH = 2V min, VIL = 0.8V max), 3-state leakage current (±5µA max), thermal resistance (101.2°C/W in SOIC-20), and −55°C to +125°C extended temperature operation.
Technical Context
The CD74ACT540M implements RCA Advanced CMOS technology with SCR-latchup resistance, enabling robust operation in noisy industrial environments. Its dual active-low output enables (OE1, OE2) allow independent control of two groups of four outputs, supporting flexible bus arbitration and hot-swap isolation.
It uses a true 3-state output architecture with defined high-impedance behavior during disable, verified by IOZ ≤ ±5µA at −55°C to +125°C. Propagation delay matching between channels (tPLH/tPHL ≤ 0.7ns skew) ensures deterministic timing in parallel data paths.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5V–5.5V - Ensures compatibility with 5V TTL logic families and stable operation across industrial voltage tolerances. |
| Output Drive | ±24mA - Sufficient to directly drive 50Ω transmission lines or fan out to 15 FAST® ICs without external buffers. |
| Propagation Delay | ≤7.2ns (tPLH/tPHL, VCC = 5V, TA = −40°C to +85°C) - Enables reliable operation in 100+ MHz bus systems with tight timing margins. |
| Input Thresholds | VIH = 2V min, VIL = 0.8V max - Matches standard TTL logic levels for seamless interfacing with legacy controllers and FPGAs. |
| 3-State Leakage | ±5µA max (TA = −55°C to +125°C) - Guarantees low standby current and minimal bus contention during disable states. |
| Operating Temp | −55°C to +125°C - Qualified for extended industrial and military-grade applications including motor drives and avionics subsystems. |
| ESD Rating | ±2000V HBM - Provides robust handling margin during PCB assembly and field maintenance without additional protection circuitry. |
Pinout & Package
CD74ACT540M is housed in a 20-pin SOIC (DW) package measuring 12.8mm × 10.3mm (including pins), with body size 12.8mm × 7.5mm. The package is RoHS-compliant, lead-finished with NiPdAu, and rated MSL Level-1 (260°C peak reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (!MR) | Master Reset (active-low) | Global asynchronous reset that forces all outputs to high-impedance regardless of OE state - critical for system-level initialization and fault recovery. |
| 2 (Q0)–9 (Q3), 12 (Q4)–19 (Q7) | Inverting buffered outputs | Eight complementary outputs grouped as Q0–Q3 (controlled by OE1) and Q4–Q7 (controlled by OE2); each provides full rail-to-rail swing and ±24mA drive capability. |
| 3 (D0)–4 (D1), 7 (D2)–8 (D3), 13 (D4)–14 (D5), 17 (D6)–18 (D7) | Data inputs | Eight independent TTL-compatible inputs accepting 0.8V/2V thresholds; input loading is 1.42 unit loads per data pin per TI Act Input Loading Table. |
| 10 (GND) | Ground reference | Dedicated power return path - must be connected to low-impedance system ground plane to maintain noise immunity and switching integrity. |
| 11 (CP) | Clock input | Rising-edge-triggered clock used only in master-reset synchronization; not required for basic buffer operation but enables coordinated reset across multiple devices. |
| 20 (VCC) | Power supply | Primary 4.5–5.5V supply - requires local 0.1µF ceramic bypass capacitor placed within 5mm of the pin to suppress high-frequency switching noise. |
Key Features
| Feature | Design Value |
|---|---|
| SCR-latchup-resistant process | Prevents destructive latch-up under transient overvoltage or ESD events - eliminates need for external current-limiting resistors in I/O protection networks. |
| Balanced propagation delays | ≤0.7ns skew between any two outputs ensures simultaneous edge alignment in parallel bus architectures, reducing setup/hold violations. |
| 50Ω transmission-line drive | Validated at +85°C per TI test condition - enables direct connection to controlled-impedance traces without series termination resistors in high-speed backplanes. |
| TTL-compatible input thresholds | VIH ≥ 2V and VIL ≤ 0.8V at VCC = 4.5–5.5V - guarantees interoperability with legacy microcontrollers, CPLDs, and discrete logic without level-shifting circuitry. |
| Extended temperature range | −55°C to +125°C operation verified per MIL-STD-883 - supports deployment in engine control units, downhole tools, and outdoor telecom infrastructure. |
Applications
| Industrial Bus Interface | Motor Control I/O Expansion |
|---|---|
Use Scenario: Isolating and buffering address/data buses between a PLC CPU and modular I/O racks operating in electrically noisy factory environments. IC Role / Device Role / Timing Role: Octal inverting buffer with dual OE control acts as directionally agnostic bus driver, enabling bidirectional data flow while preventing signal corruption during hot-swap insertion. Use Value: ±24mA drive strength maintains signal integrity across 30cm ribbon cables; 3-state outputs eliminate bus contention during rack reconfiguration. | Use Scenario: Interfacing FPGA-based motion controller outputs to isolated gate drivers in servo amplifier modules. IC Role / Device Role / Timing Role: Level-shifting and current-boosting buffer translating 3.3V FPGA GPIO signals to 5V-tolerant, high-current drive for optocoupler inputs. Use Value: TTL-compatible input thresholds accept 3.3V logic highs directly; 7.2ns max propagation delay preserves timing margins in 20kHz PWM update cycles. |
| Avionics Data Acquisition | Test Equipment Signal Routing |
Use Scenario: Multiplexing analog sensor readings from multiple RTD or thermocouple front-ends into a centralized ADC in airborne environmental monitoring systems. IC Role / Device Role / Timing Role: Inverting 3-state buffer providing channel-selectable signal gating and noise-immune transmission over 15cm PCB traces. Use Value: −55°C to +125°C qualification ensures reliability at cruise altitudes; 2000V HBM ESD rating withstands static discharge during maintenance. | Use Scenario: Dynamic reconfiguration of signal paths in automated test equipment (ATE) platforms using relayless solid-state switching. IC Role / Device Role / Timing Role: High-speed bus switch enabling sub-10ns path selection between DUT interfaces and measurement instruments via OE-controlled output groups. Use Value: Dual OE pins allow independent enable/disable of two 4-bit lanes, supporting concurrent testing of multiple DUTs without hardware reconfiguration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT540N | Same ACT-series electrical specs, but in PDIP-20 package (24.33mm × 9.4mm) with higher RθJA (69°C/W) and −40°C to +85°C temp range. | Limited to commercial/industrial ambient conditions; unsuitable for extended temperature or space-constrained layouts. | Select when through-hole assembly is required and thermal budget allows higher junction temperature rise. |
| CD74ACT540M96 | Identical die and SOIC-20 packaging, differing only in tape-and-reel packaging (2000 pcs/reel vs. tube); identical marking (ACT540M) and MSL Level-1 rating. | No functional or performance difference - solely a logistics variant for automated SMT placement. | Select for high-volume pick-and-place manufacturing where reel-fed feeders are used. |
Compared with SN74ACT540N and CD74ACT540M96, CD74ACT540M offers superior thermal performance in compact layouts and guaranteed operation across −55°C to +125°C, making it the preferred choice for mission-critical embedded systems where reliability and density are prioritized over manual assembly convenience.
Availability
CD74ACT540M is available at Aetrix Electronics and suitable for industrial automation, avionics data acquisition, and motor control I/O expansion requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for CD74ACT540M 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
Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of experience delivering high-reliability logic and interface solutions for industrial, automotive, and aerospace markets.
The CD74ACT540M belongs to TI's Advanced CMOS (ACT) logic family, engineered specifically for high-speed, low-power bus interface applications demanding TTL compatibility, robust noise immunity, and extended temperature operation in harsh environments.
FAQ
What is the maximum recommended supply voltage for CD74ACT540M?
The absolute maximum supply voltage for CD74ACT540M is 6V, but the recommended operating range is strictly 4.5V to 5.5V per TI's SCHS285B datasheet Section 4.3. Operation above 5.5V risks exceeding oxide breakdown limits and invalidates parametric guarantees including VOH/VOL, propagation delay, and ICC. For sustained reliability in industrial applications, maintain VCC ≤ 5.5V with ±5% tolerance.
Does CD74ACT540M support hot-swap operation?
Yes, CD74ACT540M supports controlled hot-swap operation when used with proper power sequencing: assert !MR before applying VCC, then enable OE1/OE2 after VCC stabilizes. Its SCR-latchup-resistant CMOS process and ±2000V HBM ESD rating (per Section 4.2) prevent damage during live insertion. However, bus transients must remain within VI < −0.5V or VI > VCC + 0.5V limits to avoid diode conduction.
How does the dual output-enable architecture of CD74ACT540M improve system design?
The dual active-low output enables (OE1, OE2) in CD74ACT540M allow independent control of two 4-bit output groups (Q0–Q3 and Q4–Q7), enabling time-multiplexed bus sharing, phased power-up sequences, and fault-isolation without external logic. This reduces component count versus using two discrete quad buffers and eliminates timing skew between enable signals inherent in cascaded enable schemes.
Can CD74ACT540M drive 75Ω coaxial cables used in test equipment?
No - CD74ACT540M is characterized for 50Ω transmission-line drive per Section 4.5 footnote (2), verified at +85°C. Driving 75Ω lines would reduce signal amplitude by ~30% and increase rise/fall time beyond specification due to impedance mismatch. For 75Ω systems, use a dedicated line driver like THS3201 or add series termination to match impedance, as confirmed by TI's Application Report SLLA165.
What is the purpose of the CP (clock) pin on CD74ACT540M?
The CP pin on CD74ACT540M is a rising-edge-triggered clock input used exclusively for synchronizing the !MR (master reset) function, ensuring metastability-free reset assertion across all internal latches. It is not required for standard buffer operation; when unused, TI recommends tying CP to VCC or GND. Its inclusion enables deterministic reset timing in synchronous systems where !MR must align with system clock edges.
CD74ACT540M Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ACT
- 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:
- 24mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
CD74ACT540M FAQ
1.How can I place an order for CD74ACT540M through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74ACT540M 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 CD74ACT540M reliable?
The price and inventory of CD74ACT540M are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74ACT540M is usually 5 days.
3.What payment methods are accepted for CD74ACT540M?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74ACT540M transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74ACT540M?
CD74ACT540M orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74ACT540M 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 CD74ACT540M?
For technical support, including CD74ACT540M datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74ACT540M requirements.
6.How does Aetrix verify that CD74ACT540M is sourced from the original manufacturer or authorized distributors?
All CD74ACT540M 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 CD74ACT540M meets industry standards.
7.What is the process for return or replacement of CD74ACT540M?
All CD74ACT540M units undergo pre-shipment inspection (PSI). If there is an issue with CD74ACT540M, 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 CD74ACT540M part is unused and in its original packaging.
Return procedure for CD74ACT540M:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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