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Texas Instruments CD74HCT240PW
- Part No.:
- CD74HCT240PW
- Manufacturer:
- Texas Instruments
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
CD74HCT240PW.pdf
- Description:
- IC BUFFER INVERT 5.5V 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:810
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Product details
Overview
CD74HCT240PW from Texas Instruments is an inverting octal buffer/line driver with three-state outputs and dual active-low output enables, designed for bidirectional bus interfacing in 5-V TTL-compatible digital systems. It delivers 8ns typical propagation delay at VCC = 5 V, CL = 15 pF, supports ±25 mA output drive, operates across –55°C to +125°C, and features buffered inputs for noise immunity in industrial control backplanes.
For engineers reviewing the CD74HCT240PW datasheet, CD74HCT240PW pinout, CD74HCT240PW application, or CD74HCT240PW equivalent, this device is selected for high-reliability 5-V bus buffering where logic inversion, low-power CMOS compatibility with LSTTL inputs, and robust thermal performance are required.
Technical Context
The CD74HCT240PW implements two independent 4-bit inverting buffer sections, each controlled by its own active-low output enable (1OE, 2OE). All eight outputs enter high-impedance state when either enable is asserted, enabling shared-bus arbitration without external logic.
Its HCT logic family ensures direct compatibility with LSTTL input thresholds (VIL ≤ 0.8 V, VIH ≥ 2.0 V) while maintaining CMOS-level input leakage (≤1 μA) and supply current (≤160 μA over temperature), making it suitable for mixed-voltage system interfaces requiring deterministic enable timing and rail-to-rail output swing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - Ensures stable operation within standard 5-V ±5% supply rails without level-shifting. |
| Propagation Delay | 9 ns typical (tPLH/tPHL) at VCC = 4.5 V, CL = 50 pF - Enables reliable timing in 30+ MHz bus cycles. |
| Output Drive | ±25 mA per output - Sustains fanout of 15 LSTTL loads without external buffers. |
| Input Thresholds | VIL = 0.8 V (max), VIH = 2.0 V (min) - Guarantees direct interface with legacy 5-V TTL logic families. |
| Operating Temp | –55°C to +125°C - Qualified for under-hood automotive, industrial motor drives, and aerospace avionics. |
| Three-State Leakage | ±5 μA max (–55°C to +125°C) - Minimizes bus contention current during high-Z state in multi-driver systems. |
| Power Dissipation Cap | CPD = 40 pF - Enables accurate dynamic power estimation (PD = VCC² × fi × (CPD + CL)) for thermal design. |
Pinout & Package
TSSOP-20 package (PW): 6.50 mm × 4.40 mm body, 0.65 mm lead pitch, surface-mount, moisture-sensitive level 1 (MSL-1).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | Inputs (1A1–1A4, 2A1–2A4) | Inverting data inputs for two 4-bit channels; buffered to reject noise and reduce loading on upstream drivers. |
| 9, 10 | Output Enables (1OE, 2OE) | Active-low controls: asserting either disables corresponding 4-bit output group into high-impedance state. |
| 11, 13, 14, 15, 16, 17, 18, 20 | Outputs (1Y1–1Y4, 2Y1–2Y4) | Inverted buffered outputs; each sinks or sources ±25 mA, compatible with LSTTL and CMOS loads. |
| 12, 19 | GND, VCC | Power pins placed adjacent to minimize ground bounce; decoupling capacitor must be placed near Pin 12 (GND) and Pin 19 (VCC). |
Key Features
| Feature | Design Value |
|---|---|
| Inverting three-state logic | Enables bidirectional bus control with polarity inversion built-in-no external inverters needed for complemented data paths. |
| Dual independent output enables | Allows selective disabling of upper/lower 4-bit lanes for partial bus isolation in memory-mapped I/O or peripheral multiplexing. |
| LSTTL-input compatible HCT family | Eliminates need for level shifters when interfacing with legacy 5-V TTL microcontrollers, FPGAs, or ASICs. |
| High-current bus driver outputs | Drives 15 LSTTL loads directly-reduces component count in dense PCB layouts with long trace runs. |
| Wide temperature range (–55°C to +125°C) | Supports deployment in unheated outdoor enclosures, engine compartments, and industrial PLC backplanes without derating. |
Applications
| Industrial PLC Backplane | Automotive Body Control Module |
|---|---|
Use Scenario: Isolating CPU address/data bus from multiple I/O expansion cards in a modular rack system. IC Role / Device Role / Timing Role: Inverting three-state buffer providing direction-controlled data path isolation between master and slave modules. Use Value: Dual OE pins allow independent gating of upper/lower byte lanes during DMA transfers, reducing bus contention and timing skew. | Use Scenario: Interfacing a 5-V microcontroller to legacy 5-V sensor clusters (e.g., door latch, window lift, mirror position) via shared CAN sub-bus. IC Role / Device Role / Timing Role: Level-translating and bus-driving interface ensuring TTL-compatible signal integrity across noisy vehicle harnesses. Use Value: LSTTL input thresholds and ±25 mA drive guarantee noise-immune communication even with 2 m cable runs and EMI exposure. |
| Test Equipment Signal Routing | Avionics Data Acquisition Unit |
Use Scenario: Multiplexing test signals between DUT and measurement instruments in automated test fixtures. IC Role / Device Role / Timing Role: Bidirectional buffer enabling reconfigurable signal path selection under microcontroller control. Use Value: 9 ns propagation delay and <18 ns transition time support precise timing alignment for high-speed digital pattern generation. | Use Scenario: Buffering analog-to-digital converter outputs to a flight management computer's 5-V parallel data bus. IC Role / Device Role / Timing Role: Radiation-tolerant (qualified to –55°C/+125°C) bus driver isolating ADC data lanes from processor bus noise. Use Value: MSL-1 TSSOP packaging and guaranteed parametric performance across full military temperature range ensure reliability in pressurized cabin environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT240PW | Identical pinout, electrical specs, and thermal ratings; manufactured by TI as second-source part with same HCT process. | No functional difference; used interchangeably in production BOMs where dual-sourcing is required. | Select SN74HCT240PW when supply chain diversification is mandated without redesign. |
| 74HCT240D,653 (Nexperia) | Same 20-pin TSSOP package, identical VCC, VIL/VIH, and output drive; tPLH/tPHL = 10 ns (typ) vs. 9 ns. | Suitable for non-critical timing paths; slightly higher propagation delay may affect margin in >25 MHz bus designs. | Choose 74HCT240D,653 for cost-sensitive industrial designs where 1 ns timing delta is acceptable. |
Compared with SN74HCT240PW and 74HCT240D,653, the CD74HCT240PW offers identical functionality and timing but is specifically qualified for extended temperature operation and widely documented in TI reference designs for harsh-environment applications.
Availability
CD74HCT240PW is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, and avionics data acquisition units requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for CD74HCT240PW 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 and embedded processing solutions for industrial, automotive, and communications markets.
The CD74HCT240PW belongs to TI's High-Speed CMOS Logic (HCT) family, engineered for seamless 5-V TTL-to-CMOS interfacing in mission-critical systems demanding wide temperature operation and low static power.
FAQ
What is the maximum output sink/source current specification for CD74HCT240PW?
The CD74HCT240PW is rated for ±25 mA per output pin under recommended operating conditions (VCC = 4.5 V to 5.5 V, TA = –55°C to +125°C). This allows direct driving of 15 LSTTL loads and ensures robust signal integrity on long PCB traces or cables. Exceeding ±25 mA risks violating absolute maximum ratings and may cause permanent damage to the CD74HCT240PW.
Does CD74HCT240PW support operation at 3.3 V?
No, CD74HCT240PW is not specified for 3.3-V operation. Its HCT family requires VCC between 4.5 V and 5.5 V to meet input threshold compatibility (VIL ≤ 0.8 V, VIH ≥ 2.0 V) and output drive specifications. For 3.3-V systems, consider TI's SN74LVC240A or similar LVC-family devices instead of CD74HCT240PW.
How does the dual output enable architecture of CD74HCT240PW improve bus management?
The CD74HCT240PW features two independent active-low output enables (1OE and 2OE), allowing separate control of its two 4-bit inverting buffer groups. This enables partial bus isolation-e.g., disabling only the lower byte during upper-byte memory access-reducing contention, minimizing switching noise, and simplifying timing in multiprocessor or DMA-driven architectures using the CD74HCT240PW.
What is the thermal resistance (RθJA) of CD74HCT240PW in its TSSOP-20 package?
The junction-to-ambient thermal resistance (RθJA) for CD74HCT240PW in the PW (TSSOP-20) package is 131.8°C/W, as specified in TI's SCHS167G datasheet. This value assumes standard JEDEC 2-layer board conditions; actual thermal performance improves with PCB copper pour and thermal vias. Designers must verify junction temperature (TJ = TA + PD × RθJA) stays below 150°C for reliable CD74HCT240PW operation.
Can CD74HCT240PW be used in place of CD74HC240PW?
CD74HCT240PW and CD74HC240PW share identical pinout and package but differ in voltage compatibility: CD74HCT240PW operates only from 4.5 V to 5.5 V with LSTTL-input thresholds, while CD74HC240PW supports 2 V to 6 V with CMOS thresholds. Substituting CD74HCT240PW for CD74HC240PW is safe only if the system uses 5-V supplies and TTL-compatible inputs; otherwise, logic level mismatches may occur. Always validate with the specific CD74HCT240PW electrical characteristics before replacement.
CD74HCT240PW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 2
- Number of Bits per Element:
- 4
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 6mA, 6mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP
CD74HCT240PW FAQ
1.How can I place an order for CD74HCT240PW through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HCT240PW 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 CD74HCT240PW reliable?
The price and inventory of CD74HCT240PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HCT240PW is usually 5 days.
3.What payment methods are accepted for CD74HCT240PW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HCT240PW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74HCT240PW?
CD74HCT240PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HCT240PW 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 CD74HCT240PW?
For technical support, including CD74HCT240PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HCT240PW requirements.
6.How does Aetrix verify that CD74HCT240PW is sourced from the original manufacturer or authorized distributors?
All CD74HCT240PW 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 CD74HCT240PW meets industry standards.
7.What is the process for return or replacement of CD74HCT240PW?
All CD74HCT240PW units undergo pre-shipment inspection (PSI). If there is an issue with CD74HCT240PW, 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 CD74HCT240PW part is unused and in its original packaging.
Return procedure for CD74HCT240PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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