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Texas Instruments SN74LVC8T245DBQR
- Part No.:
- SN74LVC8T245DBQR
- Manufacturer:
- Texas Instruments
- Package:
- 24-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
SN74LVC8T245DBQR.pdf
- Description:
- IC TRANSLATION TXRX 5.5V 24SSOP
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
SN74LVC8T245 from Texas Instruments is an 8-bit dual-supply non-inverting bus transceiver enabling bidirectional voltage-level translation between 1.65V and 5.5V domains. It features independent VCCA (1.65–5.5V) and VCCB (1.65–5.5V) rails, 3-state outputs controlled by DIR and OE pins referenced to VCCA, and Ioff support for partial-power-down operation. It is used in mixed-voltage system interconnects such as 1.8V microcontrollers interfacing with 3.3V or 5V peripherals.
For engineers reviewing the SN74LVC8T245 datasheet, SN74LVC8T245 pinout, SN74LVC8T245 application, or SN74LVC8T245 equivalent, key selection criteria include configurable dual-rail operation, glitch-free power sequencing, VCC isolation behavior, robust ESD ratings (±4000V HBM), and verified 8-bit bidirectional translation across 1.8V/2.5V/3.3V/5V nodes.
Technical Context
The SN74LVC8T245 implements asynchronous bidirectional data flow using a direction-control (DIR) signal referenced to VCCA and an output-enable (OE) signal also referenced to VCCA. Its dual-rail architecture allows A-port I/Os to track VCCA and B-port I/Os to track VCCB, enabling translation in either direction without external level-shifting circuitry.
VCC isolation ensures all I/Os enter high-impedance state when either VCCA or VCCB falls below 100 mV or floats; Ioff limits backflow current during partial power-down. Control logic is fully static, and input circuits remain active regardless of OE/DIR state to prevent excessive ICCZ.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCCA / VCCB Range | 1.65V to 5.5V each - enables translation between any pair of common logic voltages (1.8V, 2.5V, 3.3V, 5V) |
| IOH / IOL (max) | ±32mA at 5V - supports driving moderate capacitive loads or parallel outputs without external buffers |
| tPLH / tPHL (max) | 23.8ns (A→B, VCCA=1.8V/VCCB=2.5V) - meets timing requirements for 25MHz+ data buses in mixed-voltage systems |
| ESD Rating (HBM) | ±4000V - exceeds JEDEC JS-001 Class 2, suitable for board-level handling without special ESD controls |
| Ioff Leakage | ±2μA max - prevents damaging backflow current when one supply is powered down while the other remains active |
| Operating Temperature | –40°C to +85°C - qualified for industrial and commercial embedded applications including PLCs and monitors |
| VIH/VIL (control inputs) | Referenced to VCCA; VIH min = VCCA × 0.65 (1.65–1.95V), 1.7V (2.3–2.7V), 2.0V (3.0–3.6V), VCCA × 0.7 (4.5–5.5V) - ensures reliable control under all supported VCCA conditions |
Pinout & Package
SN74LVC8T245DBQR is packaged in a 24-pin SSOP (DBQ) with dimensions 8.65mm × 6mm. The package includes three GND pins (11, 12, 13) for low-impedance return paths and dual VCCB pins (23, 24) to reduce supply noise.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCCA (Pin 1) | A-port supply rail | References A-port I/O thresholds and control inputs (DIR, OE); must be stable before enabling device |
| DIR (Pin 2) | Direction control input | High = A→B data flow; Low = B→A data flow; referenced to VCCA, not VCCB |
| A1–A8 (Pins 3–10) | A-port bidirectional I/Os | Track VCCA voltage; require defined logic levels at all times to avoid excess ICCZ |
| GND (Pins 11, 12, 13) | Ground reference | Three dedicated ground pins minimize ground bounce and improve noise immunity in high-speed switching |
| B8–B1 (Pins 14–21) | B-port bidirectional I/Os | Track VCCB voltage; electrically isolated from A-port except during active data transfer |
| OE (Pin 22) | Output enable input | High = all outputs high-impedance; Low = outputs enabled per DIR state; referenced to VCCA |
| VCCB (Pins 23, 24) | B-port supply rail | Dual pins reduce IR drop and improve decoupling for B-port I/Os; must be stable before enabling |
Key Features
| Feature | Design Value |
|---|---|
| Fully configurable dual-rail operation | VCCA and VCCB independently set from 1.65V to 5.5V - eliminates need for discrete level shifters in multi-voltage designs |
| VCC isolation & disconnect | Outputs go high-impedance if either VCCA or VCCB drops below 100mV or floats - prevents bus contention during power sequencing |
| Glitch-free power supply sequencing | No defined ramp order required for VCCA/VCCB - avoids false data transitions during power-up/down in complex systems |
| Ioff partial-power-down support | Input/output leakage ≤ ±2μA when powered down - protects downstream devices from backflow current in hot-swap or sleep modes |
| Robust ESD protection | ±4000V HBM, ±1000V CDM - meets industrial handling requirements without additional protection circuitry |
Applications
| Industrial PLC Interface | Flat-Panel Monitor Control |
|---|---|
Use Scenario: Interfacing a 3.3V ARM-based controller with legacy 5V I/O modules in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional voltage translator enabling real-time status reporting and command execution across voltage domains. Use Value: Eliminates need for discrete MOSFET translators or resistive level-shifters, reducing BOM count and PCB area while maintaining signal integrity up to 25MHz. |
Use Scenario: Connecting a 1.8V video processor to 3.3V display timing controller and EDID EEPROM in flat-panel monitors. IC Role / Device Role / Timing Role: Asynchronous bidirectional bus transceiver managing DDC/CI communication and panel configuration data. Use Value: Supports hot-plug detection and dynamic resolution negotiation without voltage-domain conflicts or timing violations. |
| Network-Attached Storage | Data Center Switch Management |
Use Scenario: Bridging 2.5V SATA controller logic with 3.3V power management ICs and thermal sensors in NAS enclosures. IC Role / Device Role / Timing Role: Level-translating control bus for fan speed, temperature monitoring, and drive presence detection. Use Value: Enables use of lower-power 2.5V controllers while retaining compatibility with standard 3.3V PMICs and sensors. |
Use Scenario: Isolating 1.8V baseband processor GPIOs from 5V switch fabric management interfaces in telecom baseband units. IC Role / Device Role / Timing Role: Voltage-translating control path for reset signaling, link status, and firmware update coordination. Use Value: Prevents latch-up or damage during independent power cycling of processor and switch subsystems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AVC8T245 | Wider VCC range (1.2V–3.6V), lower propagation delay (≤12.6ns), but no 5V support | Optimized for sub-3.3V ultra-low-voltage systems only; cannot translate to or from 5V | Select when operating exclusively below 3.6V and requiring faster switching; avoid for 5V interface needs. |
| TXB0108 | Auto-direction sensing (no DIR pin), supports 1.2V–3.6V translation, higher Ioff (±5μA) | Eliminates direction-control logic but lacks deterministic control for synchronous protocols like SPI or parallel buses | Select for simple GPIO expansion where direction is predictable; avoid for bidirectional data buses requiring precise DIR timing. |
Compared with SN74AVC8T245 and TXB0108, the SN74LVC8T245 uniquely supports full 1.65V–5.5V dual-rail operation with explicit DIR control and VCC isolation-making it the only option among the three for robust 5V-compatible mixed-voltage system interconnects requiring guaranteed glitch-free sequencing.
Availability
SN74LVC8T245DBQR is available at Aetrix Electronics and suitable for industrial PLCs, flat-panel monitor control systems, and network-attached storage platforms requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for SN74LVC8T245DBQR 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 connectivity technologies, with over 90 years of innovation in industrial, automotive, and communications markets.
The SN74LVC8T245 belongs to TI's LVC logic family, designed specifically for low-voltage, high-speed bidirectional bus translation in mixed-supply systems where reliability, power sequencing robustness, and wide voltage interoperability are critical.
FAQ
What voltage ranges does the SN74LVC8T245 support on its A and B ports?
The SN74LVC8T245 supports independent supply voltages from 1.65V to 5.5V on both VCCA (A port) and VCCB (B port). This allows translation between any combination of standard logic domains - including 1.8V ↔ 2.5V, 1.8V ↔ 3.3V, 1.8V ↔ 5V, 3.3V ↔ 5V - without external components. The device is not rated for operation below 1.65V.
How does the SN74LVC8T245 handle power sequencing between VCCA and VCCB?
The SN74LVC8T245 features glitch-free power supply sequencing: either VCCA or VCCB may be powered on or off in any order without causing spurious output transitions. If either supply drops below 100 mV or floats, the VCC isolation feature forces all I/Os into high-impedance mode, preventing bus contention. This behavior is confirmed in TI's SCES584D datasheet Section 7.3.3 and 7.3.5.
Can the SN74LVC8T245 operate with DIR and OE referenced to VCCB instead of VCCA?
No. The SN74LVC8T245 explicitly references DIR and OE inputs to VCCA, as stated in the datasheet Sections 3, 4, and 7.3.1. Applying control signals relative to VCCB violates the recommended operating conditions and may result in undefined logic states or increased power consumption. All control inputs must be driven within the VIH/VIL thresholds specified relative to VCCA.
What is the maximum data rate supported by the SN74LVC8T245 in a typical 3.3V-to-5V translation setup?
In a 3.3V-to-5V configuration (VCCA = 3.3V, VCCB = 5V), the SN74LVC8T245 achieves tPLH/tPHL ≤ 6.3ns (A→B) and ≤ 6.0ns (B→A), supporting reliable operation up to ≥25MHz for parallel bus applications. Real-world throughput depends on load capacitance and trace routing; TI recommends CL ≤ 15pF and proper bypassing per Section 8.4.
Does the SN74LVC8T245DBQR package include thermal pad exposure for improved heat dissipation?
No. The DBQR (SSOP-24) package does not incorporate an exposed thermal pad. Thermal performance relies on PCB copper pour connected to the three GND pins (11, 12, 13) and proper decoupling. For enhanced thermal management, TI offers the RHL (VQFN-24) variant with an exposed thermal pad and lower RθJA (48.3°C/W).
SN74LVC8T245DBQR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LVC
- Package/Case:
- 24-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Logic Type:
- Translation Transceiver
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 32mA, 32mA
- Voltage - Supply:
- 1.65V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-SSOP
SN74LVC8T245DBQR FAQ
1.How can I place an order for SN74LVC8T245DBQR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LVC8T245DBQR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
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The price and inventory of SN74LVC8T245DBQR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LVC8T245DBQR is usually 5 days.
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Once your SN74LVC8T245DBQR 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 SN74LVC8T245DBQR?
For technical support, including SN74LVC8T245DBQR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LVC8T245DBQR requirements.
6.How does Aetrix verify that SN74LVC8T245DBQR is sourced from the original manufacturer or authorized distributors?
All SN74LVC8T245DBQR 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 SN74LVC8T245DBQR meets industry standards.
7.What is the process for return or replacement of SN74LVC8T245DBQR?
All SN74LVC8T245DBQR units undergo pre-shipment inspection (PSI). If there is an issue with SN74LVC8T245DBQR, 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 SN74LVC8T245DBQR part is unused and in its original packaging.
Return procedure for SN74LVC8T245DBQR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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