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Texas Instruments SN74HC245DW
- Part No.:
- SN74HC245DW
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74HC245DW.pdf
- Description:
- IC TXRX NON-INVERT 6V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:599
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Product details
Overview
SN74HC245DW 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 bus buffering and industrial I/O expansion.
For engineers reviewing the SN74HC245DW datasheet, SN74HC245DW pinout, SN74HC245DW application, or SN74HC245DW equivalent, key selection criteria include its 20-pin SOIC (DW) package, 3-state bidirectional operation, wide supply range, low ICC (80 µA max), and compatibility with LSTTL loads - all critical for legacy-compatible bus interface designs requiring voltage-level flexibility and bus contention control.
Technical Context
The SN74HC245DW implements a dual-rail CMOS transceiver architecture with independent DIR and OE control inputs. Its functional modes-A→B, B→A, and high-impedance isolation-are determined solely by DIR and OE logic levels, eliminating external timing dependencies. The device uses balanced output drivers with controlled edge rates to minimize ringing on capacitive bus loads.
It features input clamp diodes and ESD protection rated to ±3000 V HBM, operates across –40°C to +85°C, and maintains stable DC parameters (VIH/VIL, VOH/VOL) across its full 2–6 V supply range. Its 3-state outputs support up to 15 LSTTL loads directly without external buffers.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2 V to 6 V - enables interoperability between 3.3 V and 5 V subsystems without level shifters |
| Propagation Delay (tpd) | 12 ns typical at VCC = 6 V, CL = 50 pF - ensures sub-25 ns cycle time for 20 MHz bus operation |
| Output Drive | ±6 mA at VCC = 5 V - sufficient to drive 15 LSTTL loads or short PCB traces without signal degradation |
| Quiescent Current (ICC) | 80 µA maximum - supports low-power standby states in battery-backed or energy-sensitive applications |
| Input Leakage Current | 1 µA maximum - prevents unintended logic transitions when inputs are pulled via high-value resistors |
| ESD Rating (HBM) | ±3000 V - meets industrial handling requirements without additional protection circuitry |
| Operating Temperature | –40°C to +85°C - qualified for commercial and extended-temperature industrial environments |
Pinout & Package
SN74HC245DW is housed in a 20-pin SOIC (DW) package measuring 12.80 mm × 7.50 mm, with standard 1.27 mm pitch and gull-wing leads suitable for reflow soldering. It is RoHS-compliant with NiPdAu lead finish and MSL Level-1 rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (DIR) | Direction Control Input | Determines data flow direction: low = B→A, high = A→B; must be stable before OE activation |
| 2–9 (A1–A8) | Port A I/O Terminals | Bidirectional data lines connected to one bus segment; high-impedance when OE = high |
| 10 (GND) | Ground Reference | Primary return path for all internal logic and output currents; requires low-inductance connection |
| 11–18 (B1–B8) | Port B I/O Terminals | Bidirectional data lines connected to second bus segment; electrically isolated from A port when OE = high |
| 19 (OE) | Output Enable Input | Active-low control: low = transceiver enabled, high = all outputs in high-impedance state |
| 20 (VCC) | Power Supply | Single-supply rail supporting 2–6 V; requires local 0.1 µF bypass capacitor per VCC pin |
Key Features
| Feature | Design Value |
|---|---|
| Wide VCC Range (2–6 V) | Enables direct interfacing between mixed-voltage domains (e.g., 3.3 V microcontroller to 5 V peripheral bus) |
| High-Current 3-State Outputs | ±6 mA drive at 5 V supports termination-resistor networks and fan-out to multiple LSTTL inputs without buffer stages |
| Low Power Consumption | 80 µA max ICC allows use in always-on system management controllers without thermal derating |
| Controlled Edge Rates | Slower transitions minimize overshoot/undershoot on long or unterminated PCB traces, reducing EMI and signal integrity risk |
| Bus Isolation Capability | OE-driven high-impedance state fully decouples A and B buses, preventing back-driving and contention during power sequencing |
Applications
| PC Motherboard Bus Buffering | Industrial I/O Expansion Module |
|---|---|
Use Scenario: Isolating and translating data between CPU-local bus and legacy ISA or LPC peripherals on embedded PC platforms. IC Role / Device Role / Timing Role: Bidirectional bus transceiver managing A/B port arbitration under software-controlled DIR and hardware-synchronized OE. Use Value: Eliminates need for discrete level shifters and direction logic gates, reducing BOM count and layout area while maintaining TTL-compatible timing margins. | Use Scenario: Interfacing programmable logic controllers (PLCs) with fieldbus modules operating at different voltage rails (e.g., 3.3 V FPGA core to 5 V RS-485 transceivers). IC Role / Device Role / Timing Role: Voltage-flexible data bridge enabling synchronous read/write cycles between heterogeneous controller and peripheral subsystems. Use Value: Supports hot-swap-safe bus isolation via OE control, preventing transient glitches during module insertion/removal in modular automation systems. |
| Network Switch Backplane Interface | Wearable Health Sensor Hub |
Use Scenario: Buffering parallel address/data lines between switch fabric ASIC and management microcontroller in enterprise Ethernet switches. IC Role / Device Role / Timing Role: Low-latency bidirectional repeater ensuring signal integrity across multi-inch PCB traces with minimal skew. Use Value: 12 ns tpd and matched A/B channel delays preserve setup/hold timing for 20+ MHz control bus operation without added clock deskew circuitry. | Use Scenario: Aggregating sensor data (ECG, SpO₂, motion) from multiple analog front-ends into a low-power ARM Cortex-M0+ MCU in compact wearable form factors. IC Role / Device Role / Timing Role: Low-quiescent-current bus isolator enabling selective power gating of sensor clusters during sleep mode. Use Value: 80 µA ICC and 1 µA input leakage allow reliable wake-up signaling over shared I²C/SPI lines without false triggers from floating nodes. |
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 | TTL-compatible input thresholds (VIH = 2 V min at VCC = 4.5 V); identical pinout and 3-state behavior | Better suited for mixed 5 V TTL/CMOS systems where input noise margin must match legacy TTL logic families | Select SN74HCT245DW when interfacing with older 5 V TTL devices; otherwise SN74HC245DW offers wider VCC flexibility |
| 74LCX245MTCX | Lower VCC range (2.0–3.6 V), higher speed (tpd = 5.5 ns @ 3.3 V), and smaller TSSOP-20 package (4.4 × 6.5 mm) | Optimized for 3.3 V-only portable electronics; not compatible with 5 V buses due to absolute max VCC = 3.6 V | Choose 74LCX245MTCX only for space-constrained, single-supply 3.3 V designs; SN74HC245DW remains preferred for dual-voltage robustness |
Compared with SN74HCT245DW and 74LCX245MTCX, SN74HC245DW uniquely balances 2–6 V operation, industrial temperature range, and SOIC-20 manufacturability - making it the default choice for retrofitting legacy 5 V systems or designing flexible voltage-domain bridges where pin compatibility and supply headroom are primary constraints.
Availability
SN74HC245DW is available at Aetrix Electronics and suitable for PC motherboard bus buffering, industrial I/O expansion modules, and network switch backplane interfaces requiring stable component supply across extended product lifecycles.
Supply support for SN74HC245DW 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, with over 90 years of innovation in logic, power management, and signal chain technologies.
The SNx4HC245 family was engineered for robust, voltage-flexible bus interfacing in computing, communications, and industrial control systems - emphasizing reliability, wide operating margins, and drop-in compatibility with legacy TTL-based architectures.
FAQ
What is the maximum supply voltage rating for SN74HC245DW?
The absolute maximum supply voltage (VCC) for SN74HC245DW is 7 V, but the recommended operating range is 2 V to 6 V. Operation above 6 V risks exceeding electrical specifications and may cause accelerated parametric drift or latent failure. All DC and AC characteristics in the datasheet are guaranteed only within the 2–6 V range, and TI does not characterize performance beyond 6 V.
Does SN74HC245DW support hot-plug operation?
SN74HC245DW supports controlled hot-plug operation when OE is held high (disabled) during insertion, preventing bus contention. Its ±3000 V HBM ESD rating and input clamp diodes protect against transient coupling, but external series resistors on A/B lines are recommended for sustained hot-swap reliability. The device itself does not include built-in hot-swap current limiting or slew-rate control.
Can SN74HC245DW drive 5 V TTL loads directly?
Yes, SN74HC245DW can drive up to 15 LSTTL loads directly when powered at 5 V, delivering ±6 mA per output with VOH ≥ 3.7 V and VOL ≤ 0.33 V under load. Its output voltage levels meet TTL input thresholds across temperature and process variation, eliminating need for external pull-ups or level translators in standard 5 V TTL interfacing.
What is the function of the DIR pin on SN74HC245DW?
The DIR (direction) pin on SN74HC245DW controls data flow direction: logic low enables transmission from B bus to A bus; logic high enables transmission from A bus to B bus. DIR must be stable before OE is asserted, and its state has no effect when OE is high (outputs disabled). DIR is a CMOS input with ≤1 µA leakage, compatible with microcontroller GPIO or dedicated control logic.
Is SN74HC245DW pin-compatible with SN74LS245?
No, SN74HC245DW is not pin-compatible with SN74LS245. While both are octal transceivers in 20-pin packages, SN74LS245 uses a 20-pin PDIP (N) or ceramic DIP (J) footprint with different pin assignments - notably DIR and OE occupy different positions. SN74HC245DW's SOIC (DW) pinout matches other HC-series 20-pin SOIC transceivers (e.g., SN74HC244DW), not LS-family devices.
SN74HC245DW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- 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:
- 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-SOIC
SN74HC245DW FAQ
1.How can I place an order for SN74HC245DW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HC245DW 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 SN74HC245DW reliable?
The price and inventory of SN74HC245DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HC245DW is usually 5 days.
3.What payment methods are accepted for SN74HC245DW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HC245DW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HC245DW?
SN74HC245DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HC245DW 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 SN74HC245DW?
For technical support, including SN74HC245DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HC245DW requirements.
6.How does Aetrix verify that SN74HC245DW is sourced from the original manufacturer or authorized distributors?
All SN74HC245DW 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 SN74HC245DW meets industry standards.
7.What is the process for return or replacement of SN74HC245DW?
All SN74HC245DW units undergo pre-shipment inspection (PSI). If there is an issue with SN74HC245DW, 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 SN74HC245DW part is unused and in its original packaging.
Return procedure for SN74HC245DW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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