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Texas Instruments SN74HCT245NS
- Part No.:
- SN74HCT245NS
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74HCT245NS.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:317
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Product details
Overview
SN74HCT245NS from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between A and B buses in 5-V logic systems. It features ±6-mA output drive at 5 V, 14-ns typical propagation delay (CL = 50 pF), and operates across 4.5 V to 5.5 V supply range - enabling robust signal integrity in industrial backplane and ribbon cable interfaces.
For engineers reviewing the SN74HCT245NS datasheet, SN74HCT245NS pinout, SN74HCT245NS application, or SN74HCT245NS equivalent, this device serves as a high-current, TTL-compatible bidirectional buffer for bus isolation, level translation, and drive-strength enhancement in factory automation, telecom infrastructure, and multi-function printer designs.
Technical Context
The SN74HCT245NS implements a dual-rail CMOS HCT process with TTL-compatible inputs and balanced push-pull outputs. Its direction-control (DIR) input selects data flow path (A→B or B→A), while active-low output-enable (OE) places all I/Os in high-impedance state for bus isolation.
It supports up to 15 LSTTL loads per output, maintains low static ICC (≤80 µA), and exhibits matched tPLH/tPHL propagation delays - critical for synchronous timing in multi-drop bus architectures where skew-sensitive communication occurs over extended traces or cables.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - accommodates standard 5-V rail tolerance without level-shifting circuitry |
| Propagation Delay (tpd) | 14 ns typical (CL = 50 pF, VCC = 5.5 V) - enables reliable operation up to ~35 MHz data rates in point-to-point links |
| Output Drive | ±6 mA at 5 V - sufficient to directly drive 15 LSTTL loads or overcome capacitive losses in 30-cm+ ribbon cables |
| Input Compatibility | TTL-voltage compatible (VIH = 2 V min, VIL = 0.8 V max) - interfaces seamlessly with legacy 5-V MCU, FPGA, and peripheral I/O |
| Static Supply Current | 80 µA maximum (ICC) - minimizes quiescent power in always-on industrial control modules |
| Off-State Leakage | ±0.5 µA max (IOZ) - ensures clean bus isolation during OE assertion, preventing unintended loading or crosstalk |
| ESD Rating | ±1500 V HBM - meets industrial handling requirements without additional protection circuitry |
Pinout & Package
SN74HCT245NS uses a 20-pin SO (Small Outline) package with 12.60 mm × 5.30 mm body size and standard 0.65-mm lead pitch. Pin 1 is DIR; pins 2–9 are A-side I/Os; pin 10 is GND; pins 11–18 are B-side I/Os; pin 19 is OE; pin 20 is VCC.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (DIR) | Direction control input | High = A→B data flow; Low = B→A - determines real-time bus arbitration path without external logic |
| 2–9 (A1–A8) | Port A bidirectional I/O | Connects to local bus (e.g., MCU data bus); electrically isolated when OE = high |
| 10 (GND) | Ground reference | Common return for all signals; center-positioned to reduce ground bounce in high-speed switching |
| 11–18 (B1–B8) | Port B bidirectional I/O | Connects to remote bus (e.g., peripheral or backplane); mirrors A-side functionality with identical drive strength |
| 19 (OE) | Active-low output enable | High = all I/Os in high-Z; Low = bidirectional operation enabled - used for bus contention avoidance and hot-swap support |
| 20 (VCC) | Power supply | 5-V nominal supply; requires local 0.1-µF bypass capacitor per VCC pin to suppress switching noise |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional bus isolation | Enables two independent data domains (e.g., master/slave) to share a single physical bus without signal contention |
| 3-state output control | OE-driven high-impedance mode allows dynamic bus sharing among multiple transceivers on same trace or connector |
| TTL-compatible inputs | Accepts standard 5-V logic thresholds (VIH ≥ 2 V, VIL ≤ 0.8 V), eliminating need for external level translators |
| Low static power consumption | 80-µA max ICC permits use in battery-backed or energy-constrained industrial modules without thermal derating |
| Matched propagation delay | Typical tpd = 14 ns with <2 ns skew between channels - preserves data validity across all 8 bits in parallel transfers |
Applications
| Factory Automation Interface | Telecom Backplane Buffer |
|---|---|
|
Use Scenario: Connecting PLC CPU to distributed I/O modules via 1-meter ribbon cable in noisy industrial environments. IC Role / Device Role / Timing Role: Bidirectional signal amplifier and bus isolator that restores edge integrity degraded by cable capacitance and EMI. Use Value: Enables error-free 10-MHz data exchange over 1-m cable where unbuffered MCU outputs would fail due to rise-time degradation and undershoot. |
Use Scenario: Interfacing line-card FPGAs to shared backplane data bus in modular telecom chassis. IC Role / Device Role / Timing Role: Direction-controlled bus transceiver providing hot-swappable module isolation and drive strength matching across slots. Use Value: Prevents bus contention during card insertion/removal and sustains signal integrity across 30-cm backplane traces with 50-pF load per segment. |
| Multi-Function Printer Data Path | Motor Drive Control Bus |
|
Use Scenario: Routing bidirectional configuration and status data between main controller and print engine ASIC over flexible flat cable. IC Role / Device Role / Timing Role: Level-consistent transceiver ensuring deterministic timing between 5-V microcontroller and 5-V peripheral ASIC. Use Value: Eliminates setup/hold violations caused by cable-induced skew, supporting reliable 8-bit parallel handshaking at 5-MHz sustained rate. |
Use Scenario: Isolating motion controller outputs from motor driver ICs in closed-loop servo systems subject to high dv/dt noise. IC Role / Device Role / Timing Role: Galvanically decoupled (via PCB layout) bus interface that prevents ground loop currents from corrupting position feedback signals. Use Value: Maintains clean digital command transmission despite 100-V/µs common-mode transients on adjacent power traces, reducing encoder error bursts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT245DW | SOIC-20 package (12.80 mm × 7.50 mm); higher RθJA (70.4°C/W) than NS package (68.9°C/W); identical electrical specs | Less compact footprint; slightly lower thermal performance in dense layouts; same functional behavior | Choose SN74HCT245DW only if legacy SOIC land pattern is fixed and NS footprint redesign is not feasible. |
| 74LCX245MTCX | Lower VCC range (2.0–3.6 V); 3.3-V tolerant inputs; 5.5-ns tpd; 24-mA drive - not 5-V compatible | Requires level-shifting for 5-V systems; optimized for low-voltage portable/embedded designs | Use 74LCX245MTCX only in new 3.3-V-only systems; not a drop-in replacement for SN74HCT245NS in 5-V infrastructure. |
Compared with SN74HCT245DW and 74LCX245MTCX, the SN74HCT245NS offers optimal balance of 5-V compatibility, SO package compactness (12.60 mm × 5.30 mm), and proven industrial reliability - making it the preferred choice for retrofitting or new designs requiring direct TTL-level interoperability without voltage translation.
Availability
SN74HCT245NS is available at Aetrix Electronics and suitable for factory automation interfaces, telecom backplane buffers, and multi-function printer data paths requiring stable component supply and long-term industrial lifecycle support.
Supply support for SN74HCT245NS 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 communications markets.
The SN74HCT245NS belongs to TI's classic 74HCT logic family, engineered for robust 5-V system interfacing with TTL compatibility, low power, and high noise immunity in harsh operating environments.
FAQ
What is the operating temperature range for SN74HCT245NS?
The SN74HCT245NS is rated for an operating free-air temperature range of –40°C to +85°C, aligning with commercial and industrial-grade requirements. This specification is confirmed in Section 6.3 (Recommended Operating Conditions) of the official Texas Instruments datasheet SCLS020H, and applies specifically to the NS package variant of the SN74HCT245NS.
Does SN74HCT245NS support 3.3-V input levels?
No, SN74HCT245NS does not guarantee reliable operation with 3.3-V inputs. Its input thresholds are TTL-compatible: VIH ≥ 2.0 V and VIL ≤ 0.8 V under 4.5–5.5 V supply, but it lacks 5-V tolerant input structure. Applying 3.3-V logic directly may result in marginal or undefined switching behavior - level-shifting is required for mixed-voltage systems.
Can SN74HCT245NS replace SN74LS245 in existing designs?
Yes, SN74HCT245NS can functionally replace SN74LS245 in most 5-V systems, offering identical pinout, direction/output-enable control, and 3-state operation. Key advantages include lower ICC (80 µA vs. ~25 mA), higher noise immunity, and CMOS input current (<1 µA vs. ~20 µA), though output drive (±6 mA) is lower than LS245's ±24 mA - verify load compatibility before substitution.
What is the maximum capacitive load SN74HCT245NS can drive reliably?
SN74HCT245NS is characterized for CL = 50 pF and CL = 150 pF in its switching specifications. At 150 pF and 5.5 V, typical tpd is 27 ns and max is 41 ns - confirming reliable operation up to at least 150 pF per output. Driving >200 pF may increase delay unpredictably and risk overshoot; for heavier loads, consider parallel outputs or dedicated line drivers.
Is SN74HCT245NS RoHS compliant?
Yes, SN74HCT245NS is RoHS compliant. Per TI's Package Option Addendum (SCLS020H, July 2026), the SN74HCT245NSR.A orderable variant carries "Yes" in the RoHS column and uses NiPdAu (NIPDAU) lead finish, meeting EU Directive 2011/65/EU requirements for hazardous substance restrictions.
SN74HCT245NS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- Packaging:
- Bulk
- 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:
- 6mA, 6mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
SN74HCT245NS FAQ
1.How can I place an order for SN74HCT245NS through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT245NS 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 SN74HCT245NS reliable?
The price and inventory of SN74HCT245NS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT245NS is usually 5 days.
3.What payment methods are accepted for SN74HCT245NS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCT245NS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HCT245NS?
SN74HCT245NS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT245NS 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 SN74HCT245NS?
For technical support, including SN74HCT245NS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT245NS requirements.
6.How does Aetrix verify that SN74HCT245NS is sourced from the original manufacturer or authorized distributors?
All SN74HCT245NS 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 SN74HCT245NS meets industry standards.
7.What is the process for return or replacement of SN74HCT245NS?
All SN74HCT245NS units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT245NS, 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 SN74HCT245NS part is unused and in its original packaging.
Return procedure for SN74HCT245NS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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