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Texas Instruments CD74HCT245M
- Part No.:
- CD74HCT245M
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
CD74HCT245M.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,227
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Product details
Overview
CD74HCT245M from Texas Instruments is a high-speed octal three-state bidirectional bus transceiver in SOIC-20 package, operating at 4.5V–5.5V with 10ns typical propagation delay (CL = 15pF), ±25mA output drive, and -55°C to +125°C temperature range-used for asynchronous data bus interfacing between microcontrollers and peripheral subsystems.
For engineers reviewing the CD74HCT245M datasheet, CD74HCT245M pinout, CD74HCT245M application, or CD74HCT245M equivalent, key selection criteria include LSTTL-compatible input thresholds (VIH ≥ 2.0V, VIL ≤ 0.8V), three-state control via DIR/OE pins, bus driving capability up to 15 LSTTL loads, and industrial-grade thermal performance in SOIC packaging.
Technical Context
The CD74HCT245M implements non-inverting bidirectional data flow between two 8-bit buses (A0–A7 and B0–B7) under direction control of the DIR input and output enable/disable control via OE. Its HCT logic family ensures direct compatibility with LSTTL inputs while delivering CMOS power efficiency.
It features balanced propagation delays (tPHL ≈ tPLH), low output transition times (≤15ns at VCC = 5V, CL = 50pF), and guaranteed three-state leakage (IOZ ≤ ±5µA at -55°C to +125°C), enabling reliable hot-swap and bus-sharing operation in mixed-voltage systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5V to 5.5V - Ensures robust operation across standard 5V rail tolerances without level-shifting. |
| Propagation Delay | 10ns typical (A↔B, CL = 15pF, TA = 25°C) - Supports >50MHz bus toggle rates in synchronous interfaces. |
| Output Drive | ±25mA per pin - Sustains signal integrity when driving 15 LSTTL loads or 50pF bus capacitance. |
| Input Thresholds | VIH ≥ 2.0V, VIL ≤ 0.8V - Guarantees noise-immune interoperability with legacy TTL logic families. |
| Operating Temp | -55°C to +125°C - Qualified for aerospace, automotive engine control, and industrial motor drive environments. |
| Three-State Leakage | ±5µA max (-55°C to +125°C) - Prevents bus contention current during isolation mode in multi-master systems. |
| Power Dissipation Cap. | 55pF - Enables accurate dynamic power estimation (PD = VCC² × fi × (CPD + CL)) for thermal design. |
Pinout & Package
CD74HCT245M is housed in a 20-pin SOIC (DW) package with 1.27mm pitch, 7.6mm width, and 2.65mm max height-designed for surface-mount assembly and IPC-7351-compliant land patterns.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (DIR) | Direction Control Input | Low = B→A data flow; High = A→B data flow; referenced to VCC/GND, TTL-compatible. |
| 2–9 (A0–A7) | Bus A I/O Port | Bidirectional data lines tied to local bus; high-impedance when OE = High or device powered down. |
| 10 (GND) | Ground Reference | Primary return path for all I/O and supply currents; requires low-inductance PCB connection. |
| 11–18 (B0–B7) | Bus B I/O Port | Bidirectional data lines connected to remote bus; electrically isolated when OE = High. |
| 19 (VCC) | Positive Supply | 4.5V–5.5V CMOS supply; bypassing with 0.1µF ceramic capacitor near pin recommended. |
| 20 (OE) | Output Enable Input | Active-Low: OE = Low enables transceiver; OE = High forces all I/O into high-impedance state. |
Key Features
| Feature | Design Value |
|---|---|
| LSTTL-Compatible Inputs | VIH ≥ 2.0V and VIL ≤ 0.8V at VCC = 5V - Eliminates need for external level shifters when interfacing with 74LS/ALS logic. |
| High-Drive Three-State Outputs | ±25mA sink/source per pin - Drives long traces, multiple receivers, or capacitive loads without external buffers. |
| Wide Temperature Range | -55°C to +125°C operation - Validated for use in under-hood automotive ECUs and military-grade avionics. |
| Low Dynamic Power | CPD = 55pF - Reduces switching power by >50% vs. equivalent LSTTL parts at same frequency and load. |
| Controlled Transition Times | tTHL/tTLH ≤ 15ns (CL = 50pF) - Minimizes EMI and ground bounce in dense PCB layouts. |
Applications
| Industrial PLC Backplane Interface | Automotive Body Control Module (BCM) |
|---|---|
|
Use Scenario: Isolating and translating data between CPU bus and distributed I/O modules over 200mm+ backplane traces. IC Role / Device Role / Timing Role: Bidirectional bus transceiver managing A/B port arbitration under DIR control and synchronized OE gating. Use Value: ±25mA drive and 10ns propagation support 25MHz burst transfers across 50pF backplane loads without signal degradation. |
Use Scenario: Interfacing 8-bit microcontroller GPIO banks with LIN cluster nodes and sensor ADCs in harsh under-dash environments. IC Role / Device Role / Timing Role: Level-translating, direction-controlled data conduit between MCU and peripheral ICs with shared bus topology. Use Value: -55°C to +125°C rating and LSTTL-compatible inputs ensure reliable startup and communication during extreme thermal cycling. |
| Test Equipment Digital Pattern Generator | Avionics Data Acquisition Unit |
|
Use Scenario: Routing programmable stimulus patterns from FPGA-based pattern memory to DUT interface connectors with selectable bus direction. IC Role / Device Role / Timing Role: Programmable-direction buffer enabling flexible test vector routing without hardware reconfiguration. Use Value: 10ns delay consistency and <15ns transition times preserve timing margins in 100MHz+ digital test waveforms. |
Use Scenario: Multiplexing ARINC 429 receiver outputs and discrete status signals onto a centralized flight data recorder bus. IC Role / Device Role / Timing Role: Radiation-tolerant (qualified per MIL-PRF-38535) bidirectional data isolator with deterministic three-state control. Use Value: Guaranteed IOZ ≤ ±5µA and wide temp range ensure fault-free bus arbitration in safety-critical airborne systems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT245N | Same HCT logic, PDIP-20 package; higher θJA (69°C/W) vs. CD74HCT245M (58°C/W); identical electrical specs. | Preferred for through-hole prototyping or legacy board upgrades where SOIC rework is impractical. | Select SN74HCT245N only when manual soldering or socket-based validation is required. |
| 74ACT245SCX | ACT family: 4.5V–5.5V, but VIH/VIL tighter (VIH ≥ 2.2V, VIL ≤ 0.8V); faster tPLH/tPHL (7.5ns typ); higher ICC (max 160µA). | Suitable for high-speed test fixtures needing sub-8ns timing margin, but less tolerant of marginal TTL input levels. | Choose 74ACT245SCX only when propagation delay <8ns is mandatory and input noise immunity is secondary. |
Compared with SN74HCT245N and 74ACT245SCX, CD74HCT245M delivers optimal balance of industrial temperature range, SOIC manufacturability, LSTTL compatibility, and thermal resistance-making it the preferred choice for volume production in automotive and industrial control.
Availability
CD74HCT245M 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 product lifecycles.
Supply support for CD74HCT245M 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, with decades of heritage in high-reliability logic families including the 74HCT series.
CD74HCT245M belongs to TI's industry-standard 74HCT logic portfolio-designed specifically for robust, drop-in replacement of legacy TTL bus interfaces while delivering CMOS power efficiency and extended temperature operation.
FAQ
What is the maximum clock/data rate supported by CD74HCT245M?
The CD74HCT245M does not operate on a clock; it is a combinatorial transceiver. Its 10ns typical propagation delay (CL = 15pF) supports reliable data handshaking up to ~50MHz in synchronous bus protocols. For sustained toggling, limit frequency based on dynamic power (PD = VCC² × fi × (CPD + CL)) and thermal limits.
Can CD74HCT245M interface directly with 3.3V logic devices?
No-CD74HCT245M requires 4.5V–5.5V VCC and has LSTTL-compatible inputs (VIH ≥ 2.0V), but its outputs swing rail-to-rail (0V/5V). Direct connection to 3.3V-only inputs risks overvoltage damage. Use a dual-supply level shifter or series resistor + clamp diode network for safe interfacing.
How does the DIR pin function in CD74HCT245M?
In CD74HCT245M, the DIR pin controls data direction unidirectionally: DIR = Low enables B→A transfer; DIR = High enables A→B transfer. It has no effect when OE = High (all I/O in high-Z). DIR must be stable before data launch to avoid metastability-induced glitches on the driven bus.
Is CD74HCT245M pin-compatible with CD74HC245M?
Yes-CD74HCT245M and CD74HC245M share identical SOIC-20 pinout, package dimensions, and terminal functions. However, CD74HC245M operates from 2V–6V and lacks LSTTL input compatibility; substituting it for CD74HCT245M may cause logic-level misreads in 5V TTL systems.
What is the recommended PCB layout practice for CD74HCT245M?
Place a 0.1µF X7R ceramic capacitor between VCC and GND within 3mm of pins 19 and 10. Route A/B bus traces as controlled-impedance differential pairs if length >50mm. Avoid routing sensitive analog traces beneath the device. Follow TI's DW0020A land pattern (IPC-7351 compliant) for reliable reflow soldering.
CD74HCT245M Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Transceiver, Non-Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 4mA, 4mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
CD74HCT245M FAQ
1.How can I place an order for CD74HCT245M through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HCT245M 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 CD74HCT245M reliable?
The price and inventory of CD74HCT245M are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HCT245M is usually 5 days.
3.What payment methods are accepted for CD74HCT245M?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HCT245M transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74HCT245M?
CD74HCT245M orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HCT245M 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 CD74HCT245M?
For technical support, including CD74HCT245M datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HCT245M requirements.
6.How does Aetrix verify that CD74HCT245M is sourced from the original manufacturer or authorized distributors?
All CD74HCT245M 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 CD74HCT245M meets industry standards.
7.What is the process for return or replacement of CD74HCT245M?
All CD74HCT245M units undergo pre-shipment inspection (PSI). If there is an issue with CD74HCT245M, 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 CD74HCT245M part is unused and in its original packaging.
Return procedure for CD74HCT245M:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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