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Texas Instruments SN74CB3T3245DWG4
- Part No.:
- SN74CB3T3245DWG4
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74CB3T3245DWG4.pdf
- Description:
- IC BUS SWITCH 8 X 1:1 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,494
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Product details
Overview
SN74CB3T3245DWG4 from Texas Instruments is an 8-bit FET bus switch with bidirectional data flow, 5Ω typical ON-state resistance, 5V-tolerant I/Os, and VCC-operated voltage translation (2.3V–3.6V). It enables level shifting between 5V, 3.3V, and 2.5V domains in mixed-mode digital systems such as USB interface bridges and memory interleaving circuits.
For engineers reviewing the SN74CB3T3245DWG4 datasheet, SN74CB3T3245DWG4 pinout, SN74CB3T3245DWG4 application, or SN74CB3T3245DWG4 equivalent, key selection criteria include its 5V-tolerant I/O operation with device powered up or down, near-zero propagation delay (<0.25 ns at 3.3V), Ioff partial-power-down support, 5pF OFF-state I/O capacitance, and standard '245-type pinout compatibility.
Technical Context
The SN74CB3T3245DWG4 implements eight independent FET-based bilateral switches controlled by a single active-low OE input. Each switch provides voltage translation where output levels track VCC-enabling 5V-to-3.3V down-shift with 3.3V VCC and 5V/3.3V-to-2.5V down-shift with 2.5V VCC.
It features undershoot clamp diodes on all I/O and control inputs, supports 0–5V signaling across data ports, and maintains high-impedance isolation during power-up/down when OE is pulled to VCC. The device meets JESD 17 latch-up (>250 mA) and JESD 22 ESD ratings (2000V HBM, 1000V CDM).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2.3V to 3.6V - Enables operation in 2.5V and 3.3V logic systems while supporting 5V-tolerant I/Os. |
| ron (Typical) | 5Ω - Minimizes voltage drop and signal distortion under 32mA load, critical for high-speed bus integrity. |
| Propagation Delay | 0.25 ns (at 3.3V, CL = 50pF) - Near-zero latency enables use in timing-critical data paths like PCI and USB interfaces. |
| I/O Capacitance (OFF) | 5 pF - Reduces capacitive loading on driving sources and improves signal rise/fall times in high-frequency buses. |
| ICC (Max) | 40 µA - Ultra-low static current supports battery-powered portable equipment and low-power embedded designs. |
| Operating Temperature | –40°C to +85°C - Qualified for industrial-grade operation without derating in ambient-constrained environments. |
| ESD Rating (HBM) | ±2000 V - Robust handling margin for assembly and field-replaceable applications without external protection. |
Pinout & Package
SN74CB3T3245DWG4 uses a 20-pin SOIC (DW) package (12.8 mm × 10.3 mm), RoHS-compliant with NiPdAu lead finish and MSL Level-1 rating (unlimited floor life at ≤30°C/60% RH).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | NC | No internal connection - Must be left unconnected; no routing or termination required. |
| 2–9 | A1–A8 | Switch input terminals - Bidirectionally connected to B1–B8 when OE is low; accept 0–5V signals regardless of VCC. |
| 10 | GND | Ground reference - Serves as return path for all internal circuitry and must be low-impedance. |
| 11–18 | B8–B1 | Switch output terminals - Mirror A-port behavior; voltage translation output tracks VCC level. |
| 19 | OE | Active-low output enable - Driven low to activate all 8 switches; high-impedance state when high or floating (pull-up recommended). |
| 20 | VCC | Power supply - Sets translation reference; bypassed with 0.1 µF capacitor per TI layout guidelines. |
Key Features
| Feature | Design Value |
|---|---|
| Mixed-mode level translation | Supports 5V→3.3V and 5V/3.3V→2.5V down-shifting with VCC tracking - eliminates need for external level shifters in multi-voltage SoC interconnects. |
| 5V-tolerant I/Os | Operates safely with 0–5.5V signals on A/B ports even when VCC = 2.3V or device is unpowered - enables hot-swap and partial-power-down system design. |
| Ioff partial-power-down | Prevents backflow current when VCC = 0V - protects upstream drivers and ensures isolation in powered-down subsystems (e.g., sleep-mode peripherals). |
| Standard '245 pinout | Pin-compatible with industry-standard 74-series bus transceivers - simplifies PCB layout reuse and legacy design migration. |
| Low capacitive loading | 5 pF OFF-state I/O capacitance - minimizes signal degradation on high-speed buses (e.g., USB 2.0, PCI-X) and reduces driver loading. |
Applications
| PCI Interface Isolation | USB 2.0 Data Line Translation |
|---|---|
|
Use Scenario: Isolating 3.3V PCI controller from 5V peripheral slots during hot-plug events. IC Role / Device Role / Timing Role: Bidirectional bus switch enabling safe voltage domain bridging with sub-nanosecond propagation delay. Use Value: Prevents overvoltage damage to 3.3V controller while maintaining full PCI timing compliance via 5Ω ron and 5pF loading. |
Use Scenario: Translating D+ and D− signals between 3.3V USB PHY and 5V legacy hub logic. IC Role / Device Role / Timing Role: Level-shifting bus switch with 5V-tolerant I/Os operating at 480 Mbps signaling rates. Use Value: Eliminates external resistive dividers or dedicated translators; preserves signal integrity with <0.25 ns tpd and 5pF Cio(OFF). |
| Memory Interleaving Control | Low-Power Portable Equipment Bus Switching |
|
Use Scenario: Dynamically routing address/data lines between two 2.5V memory banks sharing a 3.3V controller. IC Role / Device Role / Timing Role: Voltage-translating 8-bit switch enabling mixed-VCC memory access without timing skew. Use Value: Supports simultaneous 2.5V/3.3V operation with VCC-tracked outputs, reducing board space vs discrete solutions. |
Use Scenario: Enabling/disabling sensor interface buses in battery-powered handheld devices during sleep cycles. IC Role / Device Role / Timing Role: Low-quiescent-current (40 µA max) bus isolator with Ioff for zero-leakage power-down. Use Value: Extends battery life by eliminating standby current leakage while preserving signal path integrity during wake transitions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus switching applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBTLV3245PWR | Lower VCC range (2.3V–3.6V same), but 3.5Ω typical ron and 3.5pF Cio(OFF); no 5V-tolerant I/Os - requires external clamping for >3.6V signals. | Best suited for pure 2.5V/3.3V systems without 5V exposure; not suitable for hot-swap or mixed-voltage I/O domains. | Select when lowest possible ron and capacitance are prioritized and 5V tolerance is unnecessary. |
| SN74AVC4T245RTER | 4-bit dual-supply translator (VCCA=1.2–3.6V, VCCB=1.2–3.6V); supports bidirectional level shift without OE pin; 8.5Ω ron (typ). | Designed for asymmetric voltage translation (e.g., 1.8V↔3.3V); lacks 5V-tolerance and Ioff - unsuitable for partial-power-down. | Choose for compact 4-bit dual-rail translation where independent supply control is required and 5V I/O is absent. |
Compared with SN74CB3T3245DWG4, SN74CBTLV3245PWR offers lower resistance and capacitance but sacrifices 5V I/O tolerance, while SN74AVC4T245RTER provides flexible dual-supply translation yet lacks Ioff and 5V robustness - making SN74CB3T3245DWG4 uniquely suited for industrial hot-swap and mixed-voltage isolation.
Availability
SN74CB3T3245DWG4 is available at Aetrix Electronics and suitable for PCI interface isolation, USB 2.0 data line translation, and memory interleaving applications requiring stable component supply, long-term industrial lifecycle support, and RoHS-compliant packaging.
Supply support for SN74CB3T3245DWG4 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 decades of expertise in high-reliability logic and interface solutions.
The SN74CB3T3245DWG4 belongs to TI's CB3T bus switch family, engineered for low-latency, voltage-agnostic digital interconnect in multi-rail systems - targeting industrial, computing, and portable electronics where robust level translation and power-aware isolation are critical.
FAQ
What is the maximum allowable I/O voltage for SN74CB3T3245DWG4 when VCC = 0V?
The SN74CB3T3245DWG4 supports 5V-tolerant I/Os even when unpowered: VI/O can safely reach 5.5V with VCC = 0V, enabled by internal protection structures and Ioff functionality. This allows safe hot-insertion into live 5V buses without risk of backfeed or latch-up, a key requirement in modular industrial backplanes and docking stations using SN74CB3T3245DWG4.
Does SN74CB3T3245DWG4 require external pull-up resistors on the OE pin?
Yes - TI recommends tying OE to VCC via a pull-up resistor during power-up/down to ensure high-impedance state before initialization. The minimum resistor value depends on the driver's sink capability; typical values range from 4.7kΩ to 10kΩ. This prevents undefined switching states and ensures deterministic isolation in systems using SN74CB3T3245DWG4 for bus arbitration or power sequencing.
Can SN74CB3T3245DWG4 translate from 3.3V to 5V?
No - the SN74CB3T3245DWG4 only supports down-translation (e.g., 5V→3.3V or 5V/3.3V→2.5V) because its output voltage tracks VCC. With VCC = 3.3V, outputs cannot exceed ~3.3V; it does not boost or up-translate. For 3.3V-to-5V translation, a dedicated dual-supply translator like SN74AVCH4T245 must be used instead of SN74CB3T3245DWG4.
What is the thermal resistance (RθJA) of SN74CB3T3245DWG4 in its SOIC package?
The SN74CB3T3245DWG4 in the DW (SOIC-20) package has a junction-to-ambient thermal resistance (RθJA) of 58°C/W, per TI's thermal characterization. This value assumes standard JEDEC 2-layer board conditions; actual performance improves with copper pour and thermal vias. Designers should verify junction temperature stays below 150°C under worst-case ICC and switching loads in their specific layout using SN74CB3T3245DWG4.
How does SN74CB3T3245DWG4 handle undershoot on data lines?
The SN74CB3T3245DWG4 integrates undershoot clamp diodes on all A/B and control pins, limiting negative excursions to –1.2V (typical) at 18mA. This protects downstream receivers from signal integrity violations caused by transmission-line reflections or fast-edge ringing - a critical feature in high-speed parallel buses where SN74CB3T3245DWG4 is deployed, such as legacy PCI or memory expansion interfaces.
SN74CB3T3245DWG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CB
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Discontinued at Digi-Key
- Type:
- Bus Switch
- Circuit:
- 8 x 1:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- -
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 2.3V ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74CB3T3245DWG4 FAQ
1.How can I place an order for SN74CB3T3245DWG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CB3T3245DWG4 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 SN74CB3T3245DWG4 reliable?
The price and inventory of SN74CB3T3245DWG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CB3T3245DWG4 is usually 5 days.
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SN74CB3T3245DWG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CB3T3245DWG4 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 SN74CB3T3245DWG4?
For technical support, including SN74CB3T3245DWG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CB3T3245DWG4 requirements.
6.How does Aetrix verify that SN74CB3T3245DWG4 is sourced from the original manufacturer or authorized distributors?
All SN74CB3T3245DWG4 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 SN74CB3T3245DWG4 meets industry standards.
7.What is the process for return or replacement of SN74CB3T3245DWG4?
All SN74CB3T3245DWG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74CB3T3245DWG4, 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 SN74CB3T3245DWG4 part is unused and in its original packaging.
Return procedure for SN74CB3T3245DWG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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