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Texas Instruments CD74HC540M
- Part No.:
- CD74HC540M
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
CD74HC540M.pdf
- Description:
- IC BUFFER INVERT 6V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,345
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Product details
Overview
CD74HC540M from Texas Instruments is an inverting octal buffer and line driver with three-state outputs, designed for bus interface and data routing in industrial control, instrumentation, and digital logic systems. It operates from 2 V to 6 V, delivers 15 LSTTL load drive capability, exhibits 9 ns typical propagation delay at 5 V/15 pF, and supports –55℃ to 125℃ ambient operation.
For engineers reviewing the CD74HC540M datasheet, CD74HC540M pinout, CD74HC540M application, or CD74HC540M equivalent, this page provides verified functional identity, SOIC-20 package mapping, inverting three-state buffer behavior, thermal and switching specifications across temperature extremes, and validated alternative options for bus-driving logic replacement.
Technical Context
The CD74HC540M implements dual independent output-enable controls (OE1, OE2) - either high forces all eight outputs into high-impedance state, while both low enables inverted data transmission. Its HC logic family ensures CMOS-level input compatibility and rail-to-rail output swing across the full 2–6 V supply range.
It features buffered inputs to reduce loading on upstream drivers, balanced rise/fall times, and fanout of 10 standard TTL loads or 15 bus-driver TTL loads. Propagation delay remains stable over temperature, with typical tPLH/tPHL = 9 ns (VCC = 5 V, CL = 15 pF, TA = 25℃) and maximum 33 ns at –55℃ to 125℃.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | High-speed CMOS (HC), not TTL-compatible - requires 2–6 V supply and delivers CMOS-level VIH/VIL thresholds. |
| Function | Inverting octal buffer with three-state outputs - each of eight channels inverts input and drives bidirectional bus when enabled. |
| Supply Voltage | 2 V to 6 V - enables direct integration with mixed-voltage systems including 3.3 V and 5 V logic domains. |
| Propagation Delay | 9 ns typical (5 V, 15 pF, 25℃); ≤33 ns max over full –55℃ to 125℃ range - supports reliable timing in harsh environments. |
| Output Drive | 15 LSTTL loads - sufficient to drive long PCB traces or multiple downstream inputs without external buffering. |
| Operating Temperature | –55℃ to 125℃ - qualified for extended industrial, automotive under-hood, and military-grade applications. |
| Input Leakage | ±1 μA max (VCC = 6 V) - minimizes static current draw and prevents unintended logic transitions in high-impedance nodes. |
Pinout & Package
CD74HC540M is housed in a 20-pin SOIC (DW) package measuring 12.80 mm × 7.50 mm, with standard 0.65 mm lead pitch and RoHS-compliant NiPdAu lead finish. Moisture sensitivity level is Level-1 (unlimited floor life at ≤30℃/60% RH).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | Inputs (A0–A7) | Inverting data inputs - each drives corresponding output when OE1 and OE2 are active low. |
| 9, 10, 11, 12, 13, 14, 15, 16 | Outputs (Y0–Y7) | Inverted, three-state outputs - high-impedance when either OE1 or OE2 is high; otherwise Yn = NOT(An). |
| 17, 18 | Output Enables (OE1, OE2) | Active-low enable controls - both must be low for output assertion; either high disables all outputs. |
| 19 | GND | Ground reference for logic and power - must be low-impedance connection to minimize noise coupling. |
| 20 | VCC | Positive supply rail - bypass with 0.1 μF ceramic capacitor placed adjacent to pin for stable switching performance. |
Key Features
| Feature | Design Value |
|---|---|
| Inverting three-state buffer function | Enables bidirectional bus control with polarity inversion - ideal for address/data latching and memory interfacing where signal inversion is required. |
| 15-LSTTL load drive capability | Reduces need for external bus transceivers in medium-density digital backplanes and I/O expansion modules. |
| Dual independent output enables | Provides fault-tolerant disable control - single-point failure in one enable path still isolates bus, improving system robustness. |
| Wide 2–6 V operating range | Supports direct interface with 3.3 V microcontrollers and 5 V legacy peripherals without level-shifting circuitry. |
| –55℃ to 125℃ temperature rating | Validated for use in uncontrolled environments such as motor drives, power supplies, and outdoor instrumentation enclosures. |
Applications
| Industrial PLC I/O Modules | Automotive Body Control Units |
|---|---|
Use Scenario: Isolating and driving 8-bit parallel sensor data buses between microcontroller and analog front-end ASICs in programmable logic controllers. IC Role / Device Role / Timing Role: Inverting three-state buffer managing direction and contention on shared data lines during ADC read cycles. Use Value: Eliminates need for discrete inverters and tristate logic gates, reducing BOM count and PCB area while maintaining deterministic timing at 10 MHz bus rates. |
Use Scenario: Interfacing 8-bit status signals (door lock, window position, mirror angle) from distributed ECUs to central body controller via shared CAN sub-bus or local parallel harness. IC Role / Device Role / Timing Role: Bus driver providing noise-immune signal conditioning and hot-swap isolation for intermittent ECU communication links. Use Value: Withstands automotive temperature extremes and delivers 15-LSTTL drive strength to overcome harness capacitance up to 100 pF per line. |
| Test Equipment Signal Routing | Avionics Data Acquisition Systems |
Use Scenario: Multiplexing calibration reference voltages and test stimulus signals across multiple DUT channels in automated test equipment. IC Role / Device Role / Timing Role: Inverting buffer enabling synchronized enable/disable of signal paths using common OE control lines. Use Value: Dual OE inputs allow hierarchical gating - e.g., global test-mode enable + per-channel selection - simplifying firmware control logic. |
Use Scenario: Buffering discrete sensor outputs (temperature, pressure, vibration) from engine-mounted transducers to flight data recorder interface cards. IC Role / Device Role / Timing Role: Radiation-tolerant (per CD74HC540M96.A military-qualified variant) inverting driver ensuring signal integrity in high-EMI avionics bays. Use Value: Guaranteed operation at –55℃ supports cold-soak testing and high-altitude deployment without derating. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar inverting octal three-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CD74HC540M96.A | Same die, identical electrical specs, same SOIC-20 package - differs only in tape-and-reel packaging (2000 pcs/reel) and MSL Level-1 marking. | No functional difference - used interchangeably in production where reel-fed SMT assembly is required. | Select CD74HC540M96.A for automated pick-and-place; CD74HC540M is obsolete but may appear in legacy inventory. |
| CD74HCT540M96.A | HCT version: TTL-compatible inputs (VIH = 2 V min, VIL = 0.8 V max), fixed 4.5–5.5 V operation - not 2–6 V flexible. | Better suited for legacy 5 V-only systems with LSTTL sources; incompatible with 3.3 V logic without level shifters. | Choose CD74HCT540M96.A only when interfacing directly to 74LS/74ALS families; avoid if mixed-voltage or low-VCC operation is needed. |
Compared with CD74HC540M, CD74HC540M96.A offers identical functionality in optimized SMT packaging, while CD74HCT540M96.A trades voltage flexibility for guaranteed TTL input compatibility - making the former ideal for new designs requiring scalability, and the latter appropriate only for strict 5 V legacy integration.
Availability
CD74HC540M is available at Aetrix Electronics and suitable for industrial automation, avionics data acquisition, and automotive body electronics requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for CD74HC540M 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 delivering analog, embedded processing, and logic solutions with emphasis on reliability, longevity, and industrial-grade qualification.
The CD74HC540M belongs to TI's legacy HC logic portfolio - engineered for robust bus interface, noise immunity, and wide-temperature operation in mission-critical digital systems where timing predictability and supply flexibility are essential.
FAQ
What is the function of CD74HC540M?
The CD74HC540M is an inverting octal buffer with three-state outputs. It accepts eight digital inputs (A0–A7), inverts each, and drives corresponding outputs (Y0–Y7) only when both output-enable pins (OE1 and OE2) are held low. When either OE is high, all outputs enter high-impedance state - enabling shared bus architectures. Its HC logic family supports 2–6 V operation and delivers 15-LSTTL load drive capability.
What package type does CD74HC540M use?
CD74HC540M uses a 20-pin SOIC (DW) package measuring 12.80 mm × 7.50 mm with 0.65 mm lead pitch. It features NiPdAu lead finish, RoHS compliance, and moisture sensitivity level (MSL) Level-1 - meaning unlimited floor life under standard storage conditions (≤30℃/60% RH). The part marking on the device reads "HC540M".
Does CD74HC540M support 3.3 V operation?
Yes, CD74HC540M fully supports 3.3 V operation. As an HC-family device, it operates across 2 V to 6 V - including nominal 3.3 V supply rails. At 3.3 V, its input thresholds scale proportionally (VIH ≈ 2.31 V, VIL ≈ 0.99 V), and it maintains specified propagation delay, drive strength, and noise margins. No level shifting is required when interfacing with 3.3 V microcontrollers or FPGAs.
How do the OE1 and OE2 pins work on CD74HC540M?
OE1 and OE2 are active-low, dual-output-enable controls on CD74HC540M. If either pin is driven high, all eight outputs (Y0–Y7) immediately enter high-impedance state - regardless of input states. Only when both OE1 and OE2 are low will the device actively drive inverted outputs. This redundancy improves fault tolerance: a single failed enable line still disables the bus, preventing contention.
Is CD74HC540M pin-compatible with CD74HCT540M?
Yes, CD74HC540M and CD74HCT540M share identical SOIC-20 pinouts and mechanical footprints. However, they differ electrically: CD74HC540M supports 2–6 V operation with CMOS input thresholds, while CD74HCT540M is limited to 4.5–5.5 V and features TTL-compatible inputs (VIH = 2 V min, VIL = 0.8 V max). Substitution requires verifying supply voltage and source logic family compatibility - they are not drop-in replacements across all systems.
CD74HC540M Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- 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:
- 7.8mA, 7.8mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
CD74HC540M FAQ
1.How can I place an order for CD74HC540M through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HC540M 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 CD74HC540M reliable?
The price and inventory of CD74HC540M are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HC540M is usually 5 days.
3.What payment methods are accepted for CD74HC540M?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HC540M transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74HC540M?
CD74HC540M orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HC540M 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 CD74HC540M?
For technical support, including CD74HC540M datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HC540M requirements.
6.How does Aetrix verify that CD74HC540M is sourced from the original manufacturer or authorized distributors?
All CD74HC540M 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 CD74HC540M meets industry standards.
7.What is the process for return or replacement of CD74HC540M?
All CD74HC540M units undergo pre-shipment inspection (PSI). If there is an issue with CD74HC540M, 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 CD74HC540M part is unused and in its original packaging.
Return procedure for CD74HC540M:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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