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Texas Instruments SN74LVC8T245DBR
- Part No.:
- SN74LVC8T245DBR
- Manufacturer:
- Texas Instruments
- Package:
- 24-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74LVC8T245DBR.pdf
- Description:
- IC TRANSLATION TXRX 5.5V 24SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,206
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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 and VCCB 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 interconnects such as 1.8V microcontroller-to-5V peripheral interfaces in industrial PLCs and flat-panel monitors.
For engineers reviewing the SN74LVC8T245 datasheet, SN74LVC8T245 pinout, SN74LVC8T245 application, or SN74LVC8T245 equivalent, key selection criteria include configurable dual-rail operation (1.65V–5.5V per port), glitch-free power sequencing, VCC isolation behavior, Ioff leakage specification (<±2 µA), and 24-pin SSOP (DB) package compatibility with legacy board layouts.
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 (1.65V–5.5V) and B-port I/Os to track VCCB (1.65V–5.5V), enabling translation across 1.8V/2.5V/3.3V/5V nodes without external level-shifting components.
VCC isolation ensures all I/Os enter high-impedance when either VCCA or VCCB falls below 100 mV or floats; Ioff circuitry limits backflow current during partial power-down. Control inputs are immune to supply sequencing order, eliminating startup glitches on data lines - critical for reliable communication in CNC controllers and network-attached storage systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCCA / VCCB Range | 1.65V to 5.5V each - enables universal translation between 1.8V, 2.5V, 3.3V, and 5V logic domains without redesign. |
| IOH / IOL (max) | ±32 mA at 5V - supports driving moderate capacitive loads or parallel outputs for higher drive strength. |
| tPLH / tPHL (max) | 23.8 ns (A→B, VCCA=1.8V/VCCB=2.5V) - meets timing requirements for 25 MHz bidirectional buses in sound bars and flat-panel displays. |
| Ioff Leakage | ±2 µA max - prevents damaging backflow current when one supply is powered down, essential for hot-swap and low-power sleep modes. |
| ESD Rating (HBM) | ±4000 V - exceeds JEDEC JESD22-A114A, ensuring robustness during handling and PCB assembly in industrial environments. |
| Operating Temperature | –40°C to +85°C - qualified for use in enterprise storage enclosures, telecom baseband units, and factory-floor PLCs. |
| VIH/VIL (control) | VCCA-referenced thresholds (e.g., VIH ≥ VCCA × 0.65) - eliminates need for external level shifters on DIR/OE control lines. |
Pinout & Package
SN74LVC8T245DBR is supplied in a 24-pin SSOP (Shrink Small Outline Package) with dimensions 8.2 mm × 7.8 mm and standard 0.65 mm lead pitch. The package includes three GND pins (11, 12, 13) for noise reduction and dual VCCB pins (23, 24) for low-impedance B-port supply routing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCCA (Pin 1) | A-port supply reference | Sets logic thresholds and drive strength for all A-side I/Os; must be stable before enabling DIR/OE. |
| DIR (Pin 2) | Direction control input | High = A→B data flow; Low = B→A; referenced to VCCA - no level shifter needed from A-side controller. |
| A1–A8 (Pins 3–10) | A-port bidirectional I/Os | Track VCCA voltage; tolerate input voltages up to 6.5V (absolute max); require defined logic levels to avoid excess ICCZ. |
| GND (Pins 11,12,13) | Ground return | Three dedicated ground pins reduce ground bounce and improve signal integrity in high-speed translation. |
| B8–B1 (Pins 14–21) | B-port bidirectional I/Os | Track VCCB voltage; electrically isolated from A-port except through transceiver core; tolerate up to 6.5V. |
| OE (Pin 22) | Output enable input | High = all outputs high-Z; Low = outputs active per DIR state; referenced to VCCA for consistent control timing. |
| VCCB (Pins 23,24) | B-port supply reference | Dual pins lower impedance path for B-port switching currents; decoupling required close to both pins. |
Key Features
| Feature | Design Value |
|---|---|
| Fully configurable dual-rail operation | VCCA and VCCB independently set from 1.65V to 5.5V - enables single device to replace multiple fixed-ratio translators in multi-voltage systems. |
| Glitch-free power supply sequencing | No defined ramp order required for VCCA/VCCB - prevents false data transitions during power-up/down in telecom switches and ultrasound scanners. |
| VCC isolation & disconnect | Outputs auto-enter high-Z if either VCCA or VCCB <100 mV or floats - protects downstream devices during brownout or hot-swap events. |
| Ioff partial-power-down support | Ioff ≤ ±2 µA ensures safe I/O states during standby; eliminates need for external isolation switches in battery-backed modules. |
| Robust ESD protection | ±4000 V HBM and ±1000 V CDM - meets industrial handling requirements without additional protection circuitry. |
Applications
| Industrial PLC Interface | Flat-Panel Monitor Bridge |
|---|---|
|
Use Scenario: Interfacing a 3.3V ARM-based motion controller with legacy 5V I/O modules in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional voltage translator managing real-time command/response traffic between mismatched voltage domains. Use Value: Eliminates discrete resistor-divider or MOSFET-based level shifters, reducing BOM count and layout area while maintaining sub-25 ns propagation delay. |
Use Scenario: Connecting a 1.8V video processor to 5V timing controller and display driver ICs in consumer sound bars and monitors. IC Role / Device Role / Timing Role: Synchronous data bridge supporting pixel clock and RGB data lanes with matched edge rates. Use Value: Enables direct connection without timing skew or signal integrity loss, verified for 2.5 MHz translation (1.8V→5V) in TI reference designs. |
| Network-Attached Storage | Telecom Baseband Unit |
|
Use Scenario: Isolating 3.3V SATA host controller signals from 5V power management and fan control circuits in NAS enclosures. IC Role / Device Role / Timing Role: Asynchronous bus isolator with OE-controlled high-Z mode during drive spin-up or firmware update. Use Value: Prevents backfeed into powered-down controller sections via Ioff and VCC isolation, improving system reliability during thermal cycling. |
Use Scenario: Level-translating control and status signals between 2.5V FPGA fabric and 5V RF front-end power amplifiers in 4G/5G baseband units. IC Role / Device Role / Timing Role: Glitch-immune interface ensuring clean reset and calibration sequences despite asymmetric supply ramping. Use Value: Guarantees no spurious pulses on PA enable lines during power sequencing - critical for meeting 3GPP RF emission compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AVC8T245RHLR | VQFN-24 (5.5 mm × 3.5 mm); supports 1.2V–3.6V range only; higher speed (tPLH ≤ 5.2 ns @ 3.3V). | Better suited for space-constrained, high-density PCBs with ≤3.6V domain translation; not compatible with 5V systems. | Select when board area is critical and 5V translation is unnecessary; requires re-layout due to different footprint and thermal pad. |
| TXB0108PWR | Auto-direction sensing; 1.2V–3.6V I/O; no DIR pin; higher Ioff (±5 µA); smaller TSSOP-20 package. | Eliminates DIR control wiring but lacks deterministic direction control - unsuitable for synchronous bidirectional protocols like SPI or parallel bus handshaking. | Choose only for simple unidirectional or auto-sensed data paths; not drop-in for SN74LVC8T245's DIR-driven applications. |
Compared with SN74AVC8T245RHLR and TXB0108PWR, the SN74LVC8T245DBR uniquely supports full 1.65V–5.5V dual-rail operation with explicit DIR control and proven robustness in industrial temperature and ESD environments - making it the preferred choice for mixed-voltage legacy system upgrades where pin compatibility and supply flexibility are mandatory.
Availability
SN74LVC8T245DBR is available at Aetrix Electronics and suitable for industrial PLCs, flat-panel monitor bridges, network-attached storage controllers, and telecom baseband units requiring stable component supply across extended temperature and mixed-voltage operating conditions.
Supply support for SN74LVC8T245DBR 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-noise-margin bidirectional translation in mixed-supply systems - targeting interoperability between legacy and next-generation digital subsystems without protocol conversion.
FAQ
What voltage ranges does the SN74LVC8T245DBR support on its A and B ports?
The SN74LVC8T245DBR 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 1.8V, 2.5V, 3.3V, and 5V logic domains. Absolute maximum ratings permit up to 6.5V on I/O pins, but sustained operation above 5.5V violates recommended conditions and risks reliability degradation. The SN74LVC8T245DBR's dual-rail design eliminates the need for external level-shifting components in mixed-voltage systems.
How does the SN74LVC8T245DBR handle power sequencing when VCCA and VCCB are powered up at different times?
The SN74LVC8T245DBR features glitch-free power supply sequencing: either VCCA or VCCB may be powered on or off in any order without causing erroneous output transitions. This is achieved through internal circuitry that holds I/Os in a known state during supply ramping. If either supply drops below 100 mV or floats, the VCC isolation feature forces all outputs into high-impedance - preventing false signaling to downstream devices. This behavior is validated across –40°C to +85°C and makes the SN74LVC8T245DBR ideal for systems with staggered power domains like CNC controllers.
Can unused I/O pins on the SN74LVC8T245DBR be left floating?
No - unused I/O pins on the SN74LVC8T245DBR must be held at a valid logic HIGH or LOW (preferably tied to VCCA, VCCB, or GND) to prevent excess ICC and ICCZ current draw and ensure stable operation. Floating inputs can cause increased power consumption, unpredictable output states, and potential latch-up risk. TI's SCBA004 application report explicitly warns against floating CMOS inputs. For unused A-port pins, tie to VCCA or GND; for unused B-port pins, tie to VCCB or GND. Control inputs (DIR, OE) must also be actively driven - OE should be pulled high via resistor during power-up to guarantee high-Z default state.
What is the maximum data rate supported by the SN74LVC8T245DBR in a typical 3.3V-to-5V translation setup?
In a 3.3V-to-5V translation configuration (VCCA = 3.3V, VCCB = 5V), the SN74LVC8T245DBR achieves tPLH/tPHL ≤ 6.3 ns and tPHZ/tPLZ ≤ 8.2 ns, supporting reliable operation up to ~25 MHz for burst-mode bidirectional data transfer. Real-world performance depends on load capacitance and trace routing; TI's typical application circuit demonstrates clean 2.5 MHz 1.8V→5V translation. For sustained high-speed use, keep CL ≤ 15 pF and use series termination or controlled-impedance traces. The SN74LVC8T245DBR's balanced push-pull outputs minimize skew between channels, preserving data eye integrity across all eight bits.
Does the SN74LVC8T245DBR support partial-power-down operation, and how is it implemented?
Yes - the SN74LVC8T245DBR supports partial-power-down via its Ioff feature. When either VCCA or VCCB is at 0V while the other remains powered, the Ioff circuitry disables all I/O output drivers, limiting leakage current to ≤±2 µA per pin. This prevents damaging backflow current into a powered-down supply rail - critical for hot-swap capability and low-power sleep modes in NAS and telecom equipment. Unlike basic high-Z states, Ioff actively clamps I/Os to safe leakage levels even with voltage applied to powered-down ports. This behavior is fully characterized in the Electrical Characteristics table and verified per JESD78 Class II latch-up standards.
SN74LVC8T245DBR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LVC
- Package/Case:
- 24-SSOP (0.209", 5.30mm 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
SN74LVC8T245DBR FAQ
1.How can I place an order for SN74LVC8T245DBR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LVC8T245DBR 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 SN74LVC8T245DBR reliable?
The price and inventory of SN74LVC8T245DBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LVC8T245DBR is usually 5 days.
3.What payment methods are accepted for SN74LVC8T245DBR?
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SN74LVC8T245DBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LVC8T245DBR 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 SN74LVC8T245DBR?
For technical support, including SN74LVC8T245DBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LVC8T245DBR requirements.
6.How does Aetrix verify that SN74LVC8T245DBR is sourced from the original manufacturer or authorized distributors?
All SN74LVC8T245DBR 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 SN74LVC8T245DBR meets industry standards.
7.What is the process for return or replacement of SN74LVC8T245DBR?
All SN74LVC8T245DBR units undergo pre-shipment inspection (PSI). If there is an issue with SN74LVC8T245DBR, 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 SN74LVC8T245DBR part is unused and in its original packaging.
Return procedure for SN74LVC8T245DBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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