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Texas Instruments CD74ACT540E
- Part No.:
- CD74ACT540E
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
CD74ACT540E.pdf
- Description:
- IC BUFF INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:840
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Product details
Overview
CD74ACT540E 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 address/data line driving in industrial and military systems. It operates at 4.5–5.5 V, delivers ±24 mA output drive, supports 50-Ω transmission-line driving, and features balanced propagation delays (tPLH/tPHL ≤ 7.2 ns at 5 V) across its eight channels.
For engineers reviewing the CD74ACT540E datasheet, CD74ACT540E pinout, CD74ACT540E application, or CD74ACT540E equivalent, this page provides verified functional mode behavior, truth table–confirmed 3-state control logic, thermal performance data (RθJA = 69 °C/W), and precise package–level mechanical dimensions for PDIP-20 layout integration.
Technical Context
The CD74ACT540E implements TTL-compatible input thresholds (VIH = 2 V min, VIL = 0.8 V max) and ACT-series CMOS output stages optimized for 5-V operation. Its dual OE pins enable independent control of two groups of four outputs, supporting split-bus isolation and dynamic load management in memory and peripheral interfaces.
It uses RCA Advanced CMOS process technology with SCR-latchup resistance and operates over −55°C to +125°C. Propagation delay matching between channels (±0.3 ns typical) and low ground bounce (VOLP = 1 V peak, VOHV = 4 V valley) ensure signal integrity during simultaneous switching in high-density PCBs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5–5.5 V - Enables direct compatibility with 5-V TTL and mixed-voltage system backplanes without level-shifting. |
| Output Drive | ±24 mA per output - Sufficient to directly drive 50-Ω transmission lines or fan out to 15 FAST® ICs without external buffers. |
| Propagation Delay | tPLH/tPHL ≤ 7.2 ns (max, VCC = 5.5 V, TA = −55°C to +125°C) - Ensures sub-8-ns timing margin for 100-MHz bus cycles with setup/hold compliance. |
| 3-State Enable Delay | tPZL/tPLZ ≤ 12.2 ns (max, VCC = 5 V) - Supports fast bus arbitration and hot-swap-ready peripheral insertion with minimal contention window. |
| Input Thresholds | VIH = 2.0 V min, VIL = 0.8 V max - Guarantees robust noise immunity (≥30% supply margin) against TTL-level inputs and board-level EMI. |
| Quiescent Current | ICC ≤ 160 µA (max, TA = −55°C to +125°C) - Enables low-static-power operation in always-on industrial controllers and battery-backed modules. |
| ESD Rating | HBM ±2000 V - Meets IEC 61000-4-2 Level 2 requirements for handling in non-ESD-protected assembly environments. |
Pinout & Package
CD74ACT540E is housed in a 20-pin plastic dual in-line package (PDIP-N), with body size 24.33 mm × 6.35 mm and overall footprint 24.33 mm × 9.4 mm. Pin 1 is located at the top-left corner with notch orientation marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (!MR) | Master Reset (active-low) | Global asynchronous reset that forces all outputs to high-impedance state regardless of OE status - critical for power-up initialization and fault recovery. |
| 2 (Q0)–9 (Q3) | Inverted Output Group A | Four buffered, inverted outputs driven by D0–D3 when OE1 = L and OE2 = L - used for isolated segment control in multiplexed address buses. |
| 10 (GND) | Ground Reference | Dedicated power return path minimizing ground bounce during simultaneous output switching - placed adjacent to VCC for optimal decoupling. |
| 11 (CP) | Clock Input | Rising-edge-triggered clock for synchronous latch functionality - not used in basic buffer mode but enables edge-aligned sampling in custom logic configurations. |
| 12 (Q4)–19 (Q7) | Inverted Output Group B | Four additional inverted outputs driven by D4–D7 under same OE control - allows full 8-bit bus buffering with group-wise enable granularity. |
| 20 (VCC) | Power Supply | +4.5 V to +5.5 V supply rail - requires local 0.1 µF ceramic bypass capacitor placed within 5 mm for stable high-frequency operation. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-Compatible Inputs | VIH ≥ 2.0 V and VIL ≤ 0.8 V at 5 V - eliminates need for external level shifters when interfacing with legacy microcontrollers and FPGA I/O banks. |
| Split 3-State Control | Dual active-low OE pins (OE1, OE2) - enables independent enabling of two 4-bit output groups for partial bus isolation and reduced switching noise. |
| SCR-Latchup Resistance | Qualified per JEDEC JESD78 Class II - ensures reliable operation in high-noise industrial environments with transient voltage spikes up to ±2000 V HBM. |
| Transmission-Line Driving | ±24 mA drive into 50 Ω loads - supports point-to-point or daisy-chained routing on controlled-impedance PCB traces without termination resistors. |
| Extended Temperature Range | −55°C to +125°C operation - validated for use in aerospace avionics, downhole oil/gas sensors, and military vehicle electronics. |
Applications
| Industrial PLC Backplane Interface | Military Data Acquisition Bus |
|---|---|
|
Use Scenario: Interfacing microcontroller GPIOs to a 16-bit parallel data bus in a programmable logic controller with hot-swap capability. IC Role / Device Role / Timing Role: Octal inverting buffer providing bidirectional bus isolation, with OE-controlled group enable for dynamic peripheral addition/removal. Use Value: Dual OE pins allow selective activation of address vs. data segments, reducing bus contention during firmware updates and field maintenance. |
Use Scenario: Signal conditioning and level translation between a radiation-hardened FPGA and analog-to-digital converter array in airborne telemetry systems. IC Role / Device Role / Timing Role: High-speed 3-state driver ensuring clean 5-V logic transitions across long backplane traces with matched propagation delays. Use Value: Balanced tPLH/tPHL ≤ 7.2 ns and low VOLP (1 V peak) maintain timing margins under simultaneous switching noise in EMI-heavy flight environments. |
| Automotive Engine Control Unit | Test Equipment Digital Pattern Generator |
|
Use Scenario: Driving solenoid control lines and sensor feedback paths in an engine control unit operating at −40°C to +125°C ambient. IC Role / Device Role / Timing Role: Inverting buffer with master reset (!MR) for fail-safe shutdown of all outputs during watchdog timeout or overtemperature events. Use Value: !MR pin forces immediate high-impedance state across all eight outputs - prevents unintended actuator activation during fault conditions. |
Use Scenario: Generating synchronized 8-bit stimulus patterns for IC functional testing in automated test equipment (ATE) platforms. IC Role / Device Role / Timing Role: Precision timing buffer delivering sub-8-ns edge alignment across all eight outputs for deterministic vector capture. Use Value: Propagation delay matching (≤0.3 ns variation) ensures skew-free pattern delivery to DUT inputs, improving test coverage accuracy. |
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 pinout, identical AC/DC specs, but TI's newer catalog version with enhanced MSL-1 reflow rating and RoHS-compliant NIPDAU finish. | Preferred for new designs requiring lead-free assembly and extended lifecycle support beyond CD74ACT540E's legacy production status. | Select SN74ACT540N for volume manufacturing with modern SMT lines; CD74ACT540E remains viable for legacy repair and MIL-spec replacements. |
| CD74AC540E | AC-series variant: wider 1.5–5.5 V supply range, lower drive (±24 mA still supported), but slower max speed (tPLH ≤ 9.5 ns at 5 V). | Suitable for mixed-voltage systems (e.g., 3.3 V logic with 5 V peripherals) where timing margin exceeds 9.5 ns and power efficiency is prioritized. | Choose CD74AC540E only if supply flexibility or lower ICC (<80 µA typ) outweighs the 2.3 ns timing penalty versus CD74ACT540E. |
Compared with SN74ACT540N and CD74AC540E, CD74ACT540E offers the highest speed (7.2 ns) and widest temperature range (−55°C to +125°C) in PDIP packaging, making it optimal for legacy military and high-reliability industrial deployments where drop-in replacement is required and reflow profile constraints are relaxed.
Availability
CD74ACT540E is available at Aetrix Electronics and suitable for industrial PLC backplane interfaces, military data acquisition systems, automotive engine control units, and test equipment digital pattern generators requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for CD74ACT540E 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 solutions for industrial, automotive, and aerospace markets.
The CD74ACT540E belongs to TI's legacy Advanced CMOS (ACT) logic family, engineered for high-speed, low-power 5-V digital interfacing in mission-critical systems demanding extended temperature operation and latchup immunity.
FAQ
What is the maximum operating temperature range for CD74ACT540E?
The CD74ACT540E is rated for operation from −55°C to +125°C, validated across the full industrial and extended military temperature range. This specification is confirmed in Section 4.3 (Recommended Operating Conditions) and Table 10-1 (Orderable Information) of the official TI datasheet SCHS285B, making CD74ACT540E suitable for downhole, avionics, and engine bay applications where thermal extremes are routine.
Does CD74ACT540E support 3.3-V input logic levels?
No, CD74ACT540E does not reliably accept 3.3-V inputs. Its ACT-series input thresholds require VIH ≥ 2.0 V (min) and VIL ≤ 0.8 V (max) at 5-V supply - while 3.3-V logic may meet VIH, marginal noise margins and undefined behavior below VIL spec make direct interfacing unsafe. Use CD74AC540E (1.5–5.5 V compatible) or a dedicated level shifter for 3.3-V source signals.
How many output enable pins does CD74ACT540E have, and what is their logic polarity?
CD74ACT540E has two active-low output enable pins: OE1 and OE2. Both must be logic low to enable the corresponding group of four outputs (Q0–Q3 for OE1, Q4–Q7 for OE2). When either OE is high, its associated outputs enter high-impedance state - a feature confirmed in Table 6-1 (Truth Table) and Figure 3-1 of the TI datasheet.
Is CD74ACT540E pin-compatible with CD74AC540E?
Yes, CD74ACT540E and CD74AC540E share identical PDIP-20 pinouts, pin functions, and package dimensions. However, they differ electrically: CD74ACT540E is optimized for 4.5–5.5 V with faster timing (7.2 ns vs. 9.5 ns), while CD74AC540E supports 1.5–5.5 V but trades speed for supply flexibility. Swapping requires verifying voltage and timing compliance in the target design.
What is the purpose of the !MR (Master Reset) pin on CD74ACT540E?
The !MR pin on CD74ACT540E is an asynchronous active-low master reset that forces all eight outputs into high-impedance state regardless of OE1/OE2 status. As documented in Table 3-1 (Pin Functions) and Section 6.3 (Device Functional Modes), this pin provides fail-safe bus isolation during power-up sequencing, watchdog timeouts, or system-level fault conditions - a key reliability feature in safety-critical systems.
CD74ACT540E Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ACT
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Active
- 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:
- Through Hole
- Supplier Device Package:
- 20-PDIP
CD74ACT540E FAQ
1.How can I place an order for CD74ACT540E through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74ACT540E 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 CD74ACT540E reliable?
The price and inventory of CD74ACT540E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74ACT540E is usually 5 days.
3.What payment methods are accepted for CD74ACT540E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74ACT540E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74ACT540E?
CD74ACT540E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74ACT540E 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 CD74ACT540E?
For technical support, including CD74ACT540E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74ACT540E requirements.
6.How does Aetrix verify that CD74ACT540E is sourced from the original manufacturer or authorized distributors?
All CD74ACT540E 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 CD74ACT540E meets industry standards.
7.What is the process for return or replacement of CD74ACT540E?
All CD74ACT540E units undergo pre-shipment inspection (PSI). If there is an issue with CD74ACT540E, 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 CD74ACT540E part is unused and in its original packaging.
Return procedure for CD74ACT540E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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