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Texas Instruments CD74AC540M
- Part No.:
- CD74AC540M
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
CD74AC540M.pdf
- Description:
- IC BUFF INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,545
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Product details
Overview
CD74AC540M from Texas Instruments is an octal inverting 3-state buffer/line driver with two active-low output enables, implemented in Advanced CMOS technology. It operates from 1.5 V to 5.5 V, delivers ±24 mA output drive per pin, supports 50 Ω transmission-line driving, and features balanced propagation delays (e.g., 6.2 ns max at 5 V, −55°C to +125°C). It is used in bus interface and data routing applications in industrial control systems.
For engineers reviewing the CD74AC540M datasheet, CD74AC540M pinout, CD74AC540M application, or CD74AC540M equivalent, key selection criteria include its inverting logic function, dual OE control, wide supply range, high noise immunity (30% of VCC), and compatibility with FAST®-level fanout while consuming significantly less power.
Technical Context
The CD74AC540M implements eight independent inverting buffer channels, each with tri-state output controlled by shared active-low OE1 and OE2 inputs. Its RCA Advanced CMOS process ensures SCR-latchup resistance and low quiescent current (≤160 µA over temperature).
It supports simultaneous switching across all outputs with verified 50 Ω transmission-line drive capability at +85°C and 75 Ω at +125°C, and exhibits balanced tPLH/tPHL propagation delays - critical for skew-sensitive bus timing in backplane and memory interface designs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Function | Inverting octal buffer with 3-state outputs |
| Supply Voltage Range | 1.5 V to 5.5 V - enables interoperability across mixed-voltage logic domains |
| Output Drive Current | ±24 mA per output - sufficient to drive 15 FAST® ICs or terminate 50 Ω lines |
| Propagation Delay | 6.2 ns max (tPHL) at 5 V, −55°C to +125°C - ensures tight timing margins in high-speed buses |
| Input Voltage Thresholds | VIH = 3.85 V, VIL = 1.65 V at VCC = 5.5 V - provides 30% noise margin relative to supply |
| Operating Temperature | −55°C to +125°C - qualified for extended industrial and military environments |
| Power Dissipation Cap. | 60 pF typical - enables accurate dynamic power estimation in high-frequency operation |
Pinout & Package
CD74AC540M is housed in a 20-pin SOIC (DW) package with 12.8 mm × 10.3 mm footprint and 12.8 mm × 7.5 mm body size. Pin 1 is located in Quadrant Q1 per tape-and-reel orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| !MR (Pin 1) | Master reset input | Active-low global reset that forces all outputs to high-impedance state regardless of OE status |
| Q0–Q7 (Pins 2,5,6,9,12,15,16,19) | Buffered inverted outputs | Eight 3-state outputs; each reflects logical inversion of corresponding D-input when enabled |
| D0–D7 (Pins 3,4,7,8,13,14,17,18) | Data inputs | Eight independent inputs feeding respective inverting buffers |
| OE1, OE2 (Pins not explicitly numbered in table but defined as dual enable inputs) | Output enable controls | Both must be low to enable outputs; either high disables all outputs to high-Z |
| GND (Pin 10), VCC (Pin 20) | Power terminals | Single-supply operation; requires local 0.1 µF bypass capacitor at VCC pin |
Key Features
| Feature | Design Value |
|---|---|
| SCR-latchup-resistant CMOS process | Ensures robust operation in noisy industrial environments without destructive latchup events |
| Balanced propagation delays | Minimizes inter-channel skew in parallel bus applications, improving setup/hold timing margins |
| 1.5 V to 5.5 V supply operation | Supports direct interfacing with 1.8 V, 2.5 V, 3.3 V, and 5 V logic families without level shifters |
| ±24 mA output drive | Enables direct termination of 50 Ω transmission lines and fanout to 15 FAST® loads |
| 30% supply noise immunity | Provides reliable noise rejection across full VCC range, reducing false triggering in EMI-prone systems |
Applications
| Industrial Bus Interface | Memory Address Buffering |
|---|---|
Use Scenario: Isolating and driving address/data buses between microcontrollers and peripheral ICs in programmable logic controllers. IC Role / Device Role / Timing Role: Inverting 3-state buffer providing bidirectional bus isolation and voltage-level translation. Use Value: Enables clean signal integrity on shared 50 Ω traces with ±24 mA drive and 6.2 ns max propagation delay. | Use Scenario: Driving address lines from an FPGA to multiple SRAM or EPROM devices in embedded instrumentation. IC Role / Device Role / Timing Role: Octal inverting buffer with dual OE control synchronizing address latching across memory banks. Use Value: Balanced tPLH/tPHL delays ensure uniform address settling time, preventing memory access errors. |
| Backplane Signal Conditioning | Legacy System Upgrades |
Use Scenario: Replacing obsolete TTL drivers on legacy backplanes requiring low-power, high-noise-immunity alternatives. IC Role / Device Role / Timing Role: Drop-in compatible octal buffer delivering FAST®-equivalent speed with CMOS power efficiency. Use Value: 1.5 V–5.5 V operation and 30% noise margin allow seamless integration without board redesign. | Use Scenario: Modernizing aging test equipment control boards where space and thermal constraints limit discrete solutions. IC Role / Device Role / Timing Role: Compact SOIC-20 buffer consolidating eight discrete inverters and enabling 3-state bus sharing. Use Value: −55°C to +125°C rating and SCR-latchup resistance ensure reliability in uncontrolled environmental enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CD74AC540M96 | Same die, identical electrical specs, SOIC-20 tape-and-reel packaging (2000 pcs/reel) | Identical functional replacement; differs only in packaging format and reel quantity | Select for automated SMT production requiring standard large-tape delivery |
| SN74AC540N | Same AC logic family, PDIP-20 package, −40°C to +85°C temp range, identical pinout and timing | Preferred for prototyping, manual assembly, or legacy through-hole designs | Select when board layout uses through-hole mounting or requires industrial-grade (not extended) temperature range |
Compared with CD74AC540M, CD74AC540M96 offers identical performance in optimized tape-and-reel form for volume SMT lines, while SN74AC540N provides the same functionality in PDIP for breadboarding and legacy systems - neither requires PCB changes, but package and temperature range differ.
Availability
CD74AC540M is available at Aetrix Electronics and suitable for industrial bus interface, memory address buffering, and backplane signal conditioning requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for CD74AC540M 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, embedded processing, and logic ICs with over 90 years of innovation in industrial, automotive, and communications markets.
The CD74AC540M belongs to TI's Advanced CMOS logic family, designed specifically for high-speed, low-power bus interface and data routing in harsh-environment industrial and defense systems.
FAQ
What is the logic function of the CD74AC540M?
The CD74AC540M is an octal inverting 3-state buffer with dual active-low output enables (OE1 and OE2). Each of its eight outputs is the logical inverse of its corresponding input (D0–D7), and all outputs enter high-impedance state when either OE is high. This function is confirmed in the truth table and functional description in TI's SCHS285B datasheet.
Does the CD74AC540M support 3.3 V operation?
Yes, the CD74AC540M fully supports 3.3 V operation within its specified 1.5 V to 5.5 V supply range. At VCC = 3.3 V, it guarantees VIH ≥ 2.1 V and VIL ≤ 0.9 V, providing 30% noise margin, and delivers ±24 mA output drive - making it suitable for direct interfacing with 3.3 V microcontrollers and FPGAs.
What is the maximum operating temperature for the CD74AC540M?
The CD74AC540M is rated for operation from −55°C to +125°C, as confirmed in Section 4.3 (Recommended Operating Conditions) and Section 6.1 (Detailed Description) of the TI SCHS285B datasheet. This extended industrial/military temperature range is enabled by its Advanced CMOS process and SOIC (DW) package construction.
Is the CD74AC540M pin-compatible with the CD74ACT540M?
No - while both are octal inverting 3-state buffers in SOIC-20 packages, the CD74AC540M (AC series) and CD74ACT540M (ACT series) differ in input thresholds and speed grading. ACT versions require ≥4.5 V supply and have TTL-compatible inputs (VIH = 2.0 V), whereas AC versions operate down to 1.5 V with CMOS thresholds. Pinout is identical, but electrical compatibility requires system-level validation.
What package type does the CD74AC540M use?
The CD74AC540M uses a 20-pin SOIC (DW) package with 12.8 mm × 10.3 mm outline and 12.8 mm × 7.5 mm body size, as documented in TI's Device Information table and PACKAGE OPTION ADDENDUM. The "M" suffix explicitly denotes this SOIC variant, distinct from PDIP (N) or SSOP (DB) options in the same family.
CD74AC540M Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AC
- 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:
- 1.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
CD74AC540M FAQ
1.How can I place an order for CD74AC540M through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74AC540M 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 CD74AC540M reliable?
The price and inventory of CD74AC540M are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74AC540M is usually 5 days.
3.What payment methods are accepted for CD74AC540M?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74AC540M transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74AC540M?
CD74AC540M orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74AC540M 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 CD74AC540M?
For technical support, including CD74AC540M datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74AC540M requirements.
6.How does Aetrix verify that CD74AC540M is sourced from the original manufacturer or authorized distributors?
All CD74AC540M 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 CD74AC540M meets industry standards.
7.What is the process for return or replacement of CD74AC540M?
All CD74AC540M units undergo pre-shipment inspection (PSI). If there is an issue with CD74AC540M, 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 CD74AC540M part is unused and in its original packaging.
Return procedure for CD74AC540M:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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