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Texas Instruments SN74AHC245PWRE4
- Part No.:
- SN74AHC245PWRE4
- Manufacturer:
- Texas Instruments
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74AHC245PWRE4.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,739
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Product details
Overview
SN74AHC245PWRE4 from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between two 8-bit buses. It operates from 2 V to 5.5 V, supports 5-V-to-3.3-V voltage translation, and features direction control (DIR) and output enable (OE) pins. Used in PC motherboard I/O expansion, server backplane interfaces, and industrial control bus bridging.
For engineers reviewing the SN74AHC245PWRE4 datasheet, SN74AHC245PWRE4 pinout, SN74AHC245PWRE4 application, or SN74AHC245PWRE4 equivalent, key selection criteria include its 20-pin TSSOP package, ±25 mA output drive per channel, 5.5 ns typical propagation delay at 5 V, and overvoltage-tolerant inputs up to 5.5 V - critical for mixed-voltage system interfacing.
Technical Context
The SN74AHC245PWRE4 implements dual-bus bidirectional communication via a single DIR input that selects A→B or B→A data flow, while OE independently enables or disables all outputs into high-impedance state. Its CMOS AHC logic family ensures rail-to-rail output swing and low static current (≤40 µA).
It supports down-translation: inputs tolerate 5.5 V regardless of VCC (2–5.5 V), enabling safe interfacing of 5-V peripherals with 3.3-V microcontrollers. Output edge rates are intentionally slowed to suppress ringing on unterminated traces - a design feature confirmed in Section 7.3 and Application Note 8.1.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2 V to 5.5 V - supports operation across 3.3-V and 5-V systems without level shifters |
| Propagation Delay (tPLH/tPHL) | 4 ns min / 6.5 ns max at VCC = 5 V, CL = 15 pF - enables >100 MHz bus timing margins |
| Output Drive | ±8 mA at VCC = 5 V - sufficient for driving multiple CMOS loads or short PCB traces |
| Input Voltage Tolerance | Up to 5.5 V independent of VCC - allows direct connection to 5-V buses while powered from 3.3 V |
| 3-State Leakage (IOZ) | ±2.5 µA max - ensures minimal bus leakage during isolation, critical for low-power standby modes |
| Operating Temperature | –40 °C to +125 °C - qualified for industrial and extended-temperature embedded applications |
| ESD Rating | 1500 V HBM - meets standard handling requirements for automated assembly lines |
Pinout & Package
TSSOP-20 (PW) package: 6.50 mm × 6.40 mm body, 0.65 mm lead pitch, surface-mount, RoHS-compliant, moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DIR (Pin 1) | Direction control input | Low = B→A data flow; High = A→B data flow - determines real-time bus directionality |
| OE (Pin 19) | Output enable input | Low = outputs active; High = all A/B ports enter high-Z - enables bus arbitration and hot-swap isolation |
| A1–A8 (Pins 2–9) | Port A I/O | Bi-directional data lines tied to local bus (e.g., MCU side); tolerate 5.5 V inputs at any VCC |
| B1–B8 (Pins 11–18) | Port B I/O | Bi-directional data lines tied to remote bus (e.g., peripheral side); identical electrical behavior to Port A |
| GND (Pin 10) | Ground reference | Primary return path for all I/O and supply currents; must be low-inductance connection |
| VCC (Pin 20) | Power supply | Single supply for logic core and I/Os; requires local 0.1 µF bypass capacitor per TI layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| Voltage translation capability | Enables 5-V-to-3.3-V down-translation without external components due to 5.5-V-tolerant inputs |
| Controlled edge rates | Slower rise/fall times minimize output ringing on unterminated traces - verified in Application Note 8.1 |
| High noise immunity | VIH/VIL thresholds scale with VCC (e.g., VIH = 3.85 V at VCC = 5.5 V), ensuring robust switching in noisy environments |
| Low power consumption | ICC ≤ 40 µA at VCC = 5.5 V - supports battery-backed or energy-sensitive system states |
| Latch-up immunity | Exceeds 250 mA per JESD17 - prevents destructive latch-up during transient overvoltage events |
Applications
| PC Motherboard I/O Expansion | Industrial PLC Backplane Interface |
|---|---|
Use Scenario: Bridging legacy parallel port or ISA-style peripherals to modern low-voltage microcontrollers on compact PC add-in cards. IC Role / Device Role / Timing Role: Bidirectional bus transceiver managing data flow between 5-V peripheral bus and 3.3-V host controller under software-directed DIR control. Use Value: Eliminates need for discrete level shifters; 5.5-V-tolerant inputs allow direct 5-V signal acceptance while powered from 3.3 V. | Use Scenario: Isolating fieldbus modules (e.g., RS-485 transceivers) from CPU-side data buffers in modular programmable logic controllers. IC Role / Device Role / Timing Role: 3-state-enabled bus isolator preventing contention during module hot-swap or firmware update sequences. Use Value: OE-controlled high-Z state ensures zero bus loading during reconfiguration - critical for deterministic real-time control cycles. |
| Server Memory Interposer | Wearable Sensor Hub Interface |
Use Scenario: Supporting DDR memory training sequences by temporarily redirecting address/control signals between memory controller and DIMM slots during calibration. IC Role / Device Role / Timing Role: Low-latency bidirectional repeater with sub-7 ns propagation delay at 5 V, synchronized via shared clock domain. Use Value: Meets tight setup/hold timing windows for DDRx command bus routing without adding jitter or skew. | Use Scenario: Interfacing 5-V analog sensor front-ends (e.g., ECG amplifiers) with 3.3-V ultra-low-power ARM Cortex-M0+ sensor hubs in fitness trackers. IC Role / Device Role / Timing Role: Voltage-translating data bridge enabling sensor data acquisition without dedicated level-shifting ICs. Use Value: Reduces BOM count and PCB area; slow edge rates suppress EMI in RF-sensitive wearable form factors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVC245APWR | Lower VCC range (1.65–3.6 V); 3.6-V max input tolerance; faster tPLH (2.5 ns typ at 3.3 V) | Restricted to 3.3-V-only systems; cannot accept 5-V inputs | Select when operating exclusively at 3.3 V and speed is prioritized over voltage flexibility |
| 74AVCH245PWRE4 | Wider VCC range (1.2–3.6 V); supports 1.8-V I/O; 3.6-V max input tolerance; higher drive (±24 mA) | Not suitable for 5-V bus interfacing; targets ultra-low-voltage mobile SoC interconnects | Select for sub-2-V domains where power efficiency and 1.8-V compatibility outweigh 5-V interface needs |
Compared with SN74LVC245APWR and 74AVCH245PWRE4, the SN74AHC245PWRE4 uniquely supports true 5-V-tolerant inputs at 3.3-V VCC - making it the only option among the three for mixed-voltage industrial or legacy peripheral interfacing without external clamping or translation.
Availability
SN74AHC245PWRE4 is available at Aetrix Electronics and suitable for PC motherboards, industrial PLCs, and server backplanes requiring stable component supply and long-term manufacturability.
Supply support for SN74AHC245PWRE4 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, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.
The SN74AHC245PWRE4 belongs to TI's AHC logic family, engineered for robust mixed-voltage bus interfacing in space-constrained industrial and computing applications where reliability and voltage translation are essential.
FAQ
What is the maximum input voltage the SN74AHC245PWRE4 can tolerate on its A/B pins?
The SN74AHC245PWRE4 accepts input voltages up to 5.5 V on all A and B I/O pins - regardless of VCC value (2 V to 5.5 V). This overvoltage tolerance is explicitly specified in Section 5.3 (Recommended Operating Conditions) and enables direct interfacing with 5-V buses while the device is powered from 3.3 V. The SN74AHC245PWRE4 does not require external clamping diodes or level shifters in such configurations.
Can the SN74AHC245PWRE4 be used for unidirectional data transfer?
Yes, the SN74AHC245PWRE4 supports unidirectional operation by holding the DIR pin at a fixed logic level (High for A→B, Low for B→A) while using OE to enable/disable the path. Its functional table (Section 7.4) confirms deterministic unidirectional flow per channel. This mode is commonly used in memory-mapped I/O or peripheral address/data latching where direction is statically assigned.
What is the thermal resistance (RθJA) of the SN74AHC245PWRE4 in its TSSOP-20 package?
The SN74AHC245PWRE4 in the PW (TSSOP-20) package has a junction-to-ambient thermal resistance (RθJA) of 122.3 °C/W, as specified in Section 5.4 (Thermal Information) of the datasheet. This value assumes standard JEDEC 2-layer board conditions and informs thermal design for continuous operation at full output load across the –40 °C to +125 °C temperature range.
Does the SN74AHC245PWRE4 support hot-swap or live-insertion applications?
Yes - the SN74AHC245PWRE4 supports hot-swap applications via its OE pin, which places all outputs in high-impedance state to prevent bus contention during insertion/removal. TI's layout guidelines (Section 8.4.1) recommend tying OE to VCC through a pullup resistor during power-up/down to ensure defined high-Z state. Its 250 mA latch-up immunity (per JESD17) further enhances robustness during transient events.
How does the SN74AHC245PWRE4 differ from the SN74AHCT245 in terms of input threshold compatibility?
The SN74AHC245PWRE4 uses CMOS input thresholds (VIH ≈ 0.7×VCC, VIL ≈ 0.3×VCC), while the SN74AHCT245 uses TTL-compatible thresholds (VIH = 2.0 V fixed, VIL = 0.8 V fixed). As a result, the SN74AHC245PWRE4 is optimized for clean CMOS signaling across its full 2–5.5 V range, whereas the SN74AHCT245 is intended for interfacing with legacy 5-V TTL outputs. This makes the SN74AHC245PWRE4 more suitable for modern mixed-supply digital systems.
SN74AHC245PWRE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHC
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- 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:
- 8mA, 8mA
- Voltage - Supply:
- 2V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP
SN74AHC245PWRE4 FAQ
1.How can I place an order for SN74AHC245PWRE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHC245PWRE4 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 SN74AHC245PWRE4 reliable?
The price and inventory of SN74AHC245PWRE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHC245PWRE4 is usually 5 days.
3.What payment methods are accepted for SN74AHC245PWRE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHC245PWRE4 transactions.
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4.How is shipping managed for SN74AHC245PWRE4?
SN74AHC245PWRE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHC245PWRE4 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 SN74AHC245PWRE4?
For technical support, including SN74AHC245PWRE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHC245PWRE4 requirements.
6.How does Aetrix verify that SN74AHC245PWRE4 is sourced from the original manufacturer or authorized distributors?
All SN74AHC245PWRE4 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 SN74AHC245PWRE4 meets industry standards.
7.What is the process for return or replacement of SN74AHC245PWRE4?
All SN74AHC245PWRE4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHC245PWRE4, 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 SN74AHC245PWRE4 part is unused and in its original packaging.
Return procedure for SN74AHC245PWRE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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