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Texas Instruments SN74HC245NS
- Part No.:
- SN74HC245NS
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74HC245NS.pdf
- Description:
- IC TXRX NON-INVERT 6V 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:944
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Product details
Overview
SN74HC245NS from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between A and B buses in digital systems. It operates from 2 V to 6 V, delivers ±6 mA output drive at 5 V, exhibits typical propagation delay of 12 ns (VCC = 6 V, CL = 50 pF), and supports isolation via active-low output enable (OE) and direction control (DIR). It is used in PC motherboard I/O buffering and industrial backplane interfaces.
For engineers reviewing the SN74HC245NS datasheet, SN74HC245NS pinout, SN74HC245NS application, or SN74HC245NS equivalent, this page provides verified functional identity, validated SO-20 package mapping, confirmed 20-pin bidirectional transceiver behavior, and real-world timing and drive specifications - all tied explicitly to the SN74HC245NS ordering variant.
Technical Context
The SN74HC245NS implements a dual-rail CMOS octal transceiver architecture with independent DIR and OE controls, enabling configurable unidirectional or bidirectional data flow without external clocking. Its logic-level translation capability (e.g., 3.3 V ↔ 5 V bus interfacing) stems from wide VCC tolerance and rail-referenced input thresholds.
Each of the eight channels features symmetrical I/O structure, high-impedance state control on both A and B sides, and balanced rise/fall times optimized to suppress ringing on unterminated lines - critical for reliable operation in server memory expansion and telecom backplane applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2 V to 6 V - enables interoperability across 3.3 V and 5 V logic domains without level shifters. |
| tpd (Typ) | 12 ns at VCC = 6 V, CL = 50 pF - ensures sub-20 ns latency for high-speed parallel bus handshaking. |
| Output Drive | ±6 mA at VCC = 5 V - sufficient to directly drive 15 LSTTL loads or terminate short PCB traces. |
| ICC (Max) | 80 µA - supports low-static-power system design in battery-backed or always-on embedded controllers. |
| Input Current | ≤1 µA max - eliminates need for pull-up/down resistors on unused DIR/OE pins under most conditions. |
| ESD Rating | ±3000 V HBM - meets industrial handling requirements without additional board-level protection. |
| Operating Temp | –40 °C to +85 °C - qualified for commercial and extended-temperature industrial environments. |
Pinout & Package
SN74HC245NS is housed in a 20-pin Small Outline Package (SO-20), body size 12.60 mm × 5.30 mm, with standard gull-wing lead form and RoHS-compliant NiPdAu finish. Pin 1 is marked by a beveled corner or notch; device orientation follows JEDEC MS-012.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | DIR | Direction control input: Low = B→A transfer; High = A→B transfer. |
| 2–9 | A1–A8 | Octal A-side bidirectional I/Os - connect to source bus (e.g., microcontroller data bus). |
| 10 | GND | Ground reference for all internal logic and output stages. |
| 11–18 | B8–B1 | Octal B-side bidirectional I/Os - connect to destination bus (e.g., peripheral interface). |
| 19 | OE | Active-low output enable: High = 3-state (high-Z); Low = enabled data path. |
| 20 | VCC | Positive supply rail - must be bypassed with ≥0.1 µF ceramic capacitor near pin. |
Key Features
| Feature | Design Value |
|---|---|
| Asynchronous bidirectional control | DIR and OE operate independently - no clock or timing constraints required for bus arbitration. |
| Ringing-suppressed edge rates | Slower CMOS transitions minimize overshoot/undershoot on unterminated 50–100 mm PCB traces. |
| Bus isolation capability | High-impedance state on both A and B ports when OE = high - prevents backfeeding between subsystems. |
| Wide voltage compatibility | Valid operation at 2 V (low-power MCU interfaces) and 6 V (legacy TTL-compatible systems). |
| Low static power consumption | ICC ≤ 80 µA at 6 V - reduces thermal load in dense multi-transceiver layouts. |
Applications
| PC Motherboard I/O Expansion | Industrial PLC Backplane Interface |
|---|---|
|
Use Scenario: Buffering parallel address/data lines between x86 CPU and legacy ISA or LPC peripherals. IC Role / Device Role / Timing Role: Bidirectional transceiver managing A/B bus handshaking with DIR-driven direction switching and OE-gated isolation during reset. Use Value: Eliminates need for discrete direction logic and enables hot-swap-safe bus partitioning without timing skew. |
Use Scenario: Interfacing 3.3 V FPGA I/O banks to 5 V sensor/actuator modules on modular PLC carrier boards. IC Role / Device Role / Timing Role: Level-tolerant octal transceiver translating logic levels while maintaining signal integrity across mixed-voltage backplanes. Use Value: Supports direct connection without external level shifters; ±6 mA drive sustains noise margin over 15 cm ribbon cable runs. |
| Network Switch Control Plane | Medical Diagnostic Equipment Data Bus |
|
Use Scenario: Isolating management processor (ARM Cortex-A) from switch fabric ASIC registers during firmware updates. IC Role / Device Role / Timing Role: 3-state-enabled bus gate preventing spurious writes during boot sequence or failover events. Use Value: OE-controlled high-Z state guarantees zero current injection into ASIC registers - critical for ASIL-B compliance. |
Use Scenario: Routing ECG/EEG analog front-end digitized data streams between ADC and DSP over shared parallel bus. IC Role / Device Role / Timing Role: Low-noise octal transceiver minimizing crosstalk-induced artifacts via controlled edge rates and ground-isolated I/O paths. Use Value: 12 ns tpd ensures sub-microsecond sampling alignment; <1 µA input leakage preserves ADC reference stability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT245NSR | CMOS-to-TTL compatible inputs (VIH = 2 V min), identical pinout and SO-20 package. | Better suited for mixed 5 V TTL/CMOS systems where input thresholds must match legacy logic families. | Select when interfacing with older 74LS or 74F devices; retains same layout but requires VCC = 4.5–5.5 V. |
| 74LCX245MTCX | Lower VCC range (2.0–3.6 V), higher speed (tpd = 5.5 ns @ 3.3 V), TSSOP-20 package (6.5 × 4.4 mm). | Optimized for ultra-low-voltage portable electronics; not 5 V tolerant on inputs or outputs. | Choose for space-constrained 3.3 V-only designs requiring faster throughput; requires PCB redesign due to smaller footprint. |
Compared with SN74HC245NS, SN74HCT245NSR offers TTL-compatible input thresholds at the cost of narrower VCC range, while 74LCX245MTCX delivers higher speed and lower voltage operation in a smaller package - neither is pin-compatible with SN74HC245NS in mixed-voltage contexts.
Availability
SN74HC245NS is available at Aetrix Electronics and suitable for PC motherboard I/O expansion, industrial PLC backplane interfaces, and network switch control plane isolation requiring stable component supply across long production lifecycles.
Supply support for SN74HC245NS 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 over 90 years of innovation in industrial, automotive, and communications markets.
The SN74HC245NS belongs to TI's 74HC logic family - engineered for robust, low-power, wide-VCC-range digital interfacing in commercial and industrial equipment where reliability and interoperability are critical.
FAQ
What is the maximum output current per channel for SN74HC245NS?
The SN74HC245NS supports ±6 mA output drive per channel at VCC = 5 V, with absolute maximum continuous output current rated at ±35 mA per pin. This allows direct driving of up to 15 LSTTL loads while maintaining VOH ≥ 3.98 V and VOL ≤ 0.26 V under defined test conditions - verified in TI's SCLS131F datasheet Section 6.5.
Does SN74HC245NS support 3.3 V to 5 V level translation?
Yes, SN74HC245NS supports bidirectional level translation between 3.3 V and 5 V buses. Its wide VCC range (2–6 V), rail-referenced VIH/VIL thresholds, and symmetrical I/O structure allow it to buffer signals across voltage domains - provided VCC is set to the higher rail (e.g., 5 V) and input voltages stay within 0–VCC limits, as confirmed in Section 6.3 and 8.4 of the official datasheet.
How should OE and DIR be biased during power-up for SN74HC245NS?
To ensure high-impedance state at power-up, OE must be held high (via pullup to VCC) and DIR may be left floating or pulled to a defined state. TI recommends a pullup resistor on OE (minimum value determined by driver sink capability) to prevent bus contention during VCC ramp - detailed in Section 8.1 and Figure 9-1 of the SN74HC245 datasheet.
Is SN74HC245NS pin-compatible with SN74HC245N (PDIP-20)?
Yes, SN74HC245NS (SO-20) and SN74HC245N (PDIP-20) share identical pin numbering, function mapping, and electrical specifications - only the package differs. Both follow JEDEC MS-012 (SO) and MS-001 (PDIP) outlines with matching 1–20 pin order, enabling drop-in replacement in existing layouts with appropriate footprint adaptation.
What is the thermal resistance (RθJA) of SN74HC245NS in its SO-20 package?
The SN74HC245NS in SO-20 (NS) package has a junction-to-ambient thermal resistance (RθJA) of 74.1 °C/W, as specified in Section 6.4 of the TI datasheet. This value assumes standard JEDEC 2-layer board conditions and informs thermal design for continuous operation at ambient temperatures up to +85 °C with ≤80 µA ICC.
SN74HC245NS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 20-SOIC (0.209", 5.30mm 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:
- 7.8mA, 7.8mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
SN74HC245NS FAQ
1.How can I place an order for SN74HC245NS through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HC245NS 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 SN74HC245NS reliable?
The price and inventory of SN74HC245NS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HC245NS is usually 5 days.
3.What payment methods are accepted for SN74HC245NS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HC245NS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HC245NS?
SN74HC245NS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HC245NS 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 SN74HC245NS?
For technical support, including SN74HC245NS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HC245NS requirements.
6.How does Aetrix verify that SN74HC245NS is sourced from the original manufacturer or authorized distributors?
All SN74HC245NS 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 SN74HC245NS meets industry standards.
7.What is the process for return or replacement of SN74HC245NS?
All SN74HC245NS units undergo pre-shipment inspection (PSI). If there is an issue with SN74HC245NS, 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 SN74HC245NS part is unused and in its original packaging.
Return procedure for SN74HC245NS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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