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Texas Instruments SN74CBT3345DGVR
- Part No.:
- SN74CBT3345DGVR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 20-TFSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74CBT3345DGVR.pdf
- Description:
- IC BUS SWITCH 8 X 1:1 20TVSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,000
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Product details
Overview
SN74CBT3345DGVR from Texas Instruments is an 8-bit high-speed bus switch with TTL-compatible control inputs, 5-Ω on-state resistance, and dual active-low/high output-enable logic enabling bidirectional port connection or high-impedance isolation in 5-V systems. It implements standard '245-type pinout for drop-in replacement in legacy bus-switching applications such as memory expansion and data path routing.
For engineers reviewing the SN74CBT3345DGVR datasheet, SN74CBT3345DGVR pinout, SN74CBT3345DGVR application, or SN74CBT3345DGVR equivalent, key selection criteria include on-resistance matching, propagation delay under 0.25 ns, dual OE control timing (enable/disable <9.1 ns), thermal performance in TVSOP (θJA = 92°C), and compatibility with 4.5–5.5-V supply rails.
Technical Context
The SN74CBT3345DGVR uses NMOS pass-gate architecture to achieve low on-resistance (5–7 Ω typical) and minimal propagation delay (0.25 ns). Its dual OE inputs-OE (active-low) and OE (active-high)-allow flexible enable logic: switch conducts when OE = L OR OE = H, and disconnects only when OE = H AND OE = L.
Designed for 5-V operation, it supports ±1 µA input leakage, 6 pF off-state I/O capacitance, and 128 mA continuous channel current. Absolute maximum ratings include −0.5 V to 7 V on VCC and I/O pins, ensuring robustness against transient overvoltage during hot-swap or level-shifting use cases.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - Ensures stable operation across industrial-grade 5-V rail tolerances. |
| ron | 5 Ω typical - Enables minimal voltage drop (<150 mV at 30 mA) and preserves signal integrity in high-speed digital paths. |
| tpd | 0.25 ns - Delivers near-zero propagation delay critical for synchronous bus timing budgets. |
| ten/tdis | 1 ns to 9.1 ns - Supports fast dynamic bus partitioning without metastability in multi-master systems. |
| Cio(OFF) | 6 pF - Limits capacitive loading on isolated buses, reducing crosstalk and power supply noise coupling. |
| IO Continuous | 128 mA - Sustains full drive capability across all 8 channels simultaneously without thermal derating. |
| θJA | 92°C/W - Specifies thermal limit for TVSOP-20 package; requires PCB copper area ≥150 mm² for full-rated operation. |
Pinout & Package
SN74CBT3345DGVR is housed in a 20-pin Thin Very Small Outline Package (TVSOP-DGV), 4.4 mm × 6.6 mm footprint, 1.2 mm max height, JEDEC MO-153 compliant, with 0.5-mm lead pitch and exposed pad not present.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OE) | Active-low output enable | Drives switch ON when low; must be tied to GND or controlled by open-drain logic. |
| 2–9 (A1–A8) | Port A input/output terminals | Bidirectional signal path; electrically identical to B-side with no internal direction control. |
| 10 (GND) | Ground reference | Primary return path for all switching currents and control logic; requires low-inductance connection. |
| 11 (VCC) | Power supply | 5-V supply input; decoupling capacitor (0.1 µF ceramic) required within 3 mm of pin. |
| 12–19 (B1–B8) | Port B input/output terminals | Electrically mirrored to A-side; supports point-to-point or bus-tap topologies. |
| 20 (OE) | Active-high output enable | Drives switch ON when high; complements OE for logic-level flexibility in mixed-control systems. |
Key Features
| Feature | Design Value |
|---|---|
| Standard '245 pinout | Enables direct mechanical and layout replacement for SN74LS245, SN74ALS245, and other 20-pin bus transceivers without PCB redesign. |
| Dual OE control logic | Supports both active-low and active-high enable signals, eliminating need for external inverters in mixed-logic systems. |
| 5-Ω on-state resistance | Reduces insertion loss and maintains signal rise/fall times below 100 ps in 50-Ω transmission environments. |
| TTL-compatible inputs | Accepts VIH ≥ 2.0 V and VIL ≤ 0.8 V, interoperating directly with 5-V CMOS, TTL, and LVTTL logic families. |
| High-speed switching | Sub-nanosecond enable/disable and propagation delays preserve setup/hold margins in >100-MHz data buses. |
Applications
| Memory Expansion Interface | PCI/ISA Bus Isolation |
|---|---|
|
Use Scenario: Expanding address/data bus width between microcontroller and parallel NOR flash or SRAM. IC Role / Device Role / Timing Role: Bidirectional bus switch isolating memory banks during access arbitration; enables time-multiplexed sharing of common data lines. Use Value: Eliminates need for tristate buffers or complex glue logic while maintaining sub-ns timing alignment across 8-bit paths. |
Use Scenario: Segmenting legacy PCI or ISA bus segments to prevent signal integrity degradation across long traces. IC Role / Device Role / Timing Role: High-speed isolation gate inserted between bus master and peripheral slots to reduce capacitive loading and reflection. Use Value: Maintains signal fidelity up to 33 MHz with <0.25 ns added delay and <6 pF off-state capacitance per line. |
| Hot-Swappable Module Interconnect | Test Access Port Multiplexing |
|
Use Scenario: Enabling safe insertion/removal of daughter cards in backplane-based industrial controllers. IC Role / Device Role / Timing Role: Controlled bus disconnect device that places A/B ports in high-Z state before physical mating/unmating. Use Value: Prevents bus contention and latch-up during live insertion by enforcing strict OE-driven isolation sequence. |
Use Scenario: Sharing JTAG TDI/TDO/TMS/TCK signals among multiple ASICs or FPGAs on a single test board. IC Role / Device Role / Timing Role: Signal router selecting one DUT at a time while keeping others electrically disconnected from test chain. Use Value: Guarantees clean signal routing with <5 Ω on-resistance and <1 ns enable skew across all 8 channels. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus-switching applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBTD3345DGVR | Includes power-down control (1.8-V compatible OE inputs) and higher VCC tolerance (up to 5.5 V), but ron increases to 7 Ω typical. | Required where mixed-voltage (1.8/3.3/5 V) control logic coexists with 5-V data paths. | Select SN74CBTD3345DGVR only if 1.8-V OE interface is mandatory; otherwise SN74CBT3345DGVR offers lower ron and simpler biasing. |
| SN74LVC245APW | Octal bus transceiver (not switch); includes direction control (DIR), 3-state outputs, and 3.3-V VCC operation only. | Suitable for unidirectional or direction-controlled data flow, not passive bidirectional switching. | Choose SN74LVC245APW only when explicit direction management is needed; SN74CBT3345DGVR is superior for transparent, bidirectional, zero-delay bus coupling. |
Compared with SN74CBTD3345DGVR, the SN74CBT3345DGVR delivers lower on-resistance and simpler 5-V-only control, while SN74LVC245APW introduces directionality and voltage translation at the cost of added latency and reduced transparency-making SN74CBT3345DGVR optimal for legacy 5-V bus extension where minimal delay and passive behavior are essential.
Availability
SN74CBT3345DGVR is available at Aetrix Electronics and suitable for memory expansion interfaces, PCI/ISA bus isolation, hot-swappable module interconnects, and JTAG test access port multiplexing requiring stable component supply and long-term industrial availability.
Supply support for SN74CBT3345DGVR 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 solutions, with over 90 years of innovation in high-reliability IC design and manufacturing.
The SN74CBT3345DGVR belongs to TI's CBT (CrossBar Technology) family of high-speed bus switches, engineered specifically for low-latency, bidirectional signal routing in 5-V digital systems without direction control overhead.
FAQ
What is the function of the dual OE inputs on the SN74CBT3345DGVR?
The SN74CBT3345DGVR features two independent output-enable inputs: OE (active-low) and OE (active-high). The switch conducts (A↔B connected) when either OE is low OR OE is high; it enters high-impedance isolation only when OE is high AND OE is low. This dual-input structure allows seamless integration with both inverting and non-inverting control logic without external gates, preserving timing integrity in complex bus arbitration schemes.
Can the SN74CBT3345DGVR operate at 3.3 V?
No, the SN74CBT3345DGVR is specified only for 4.5 V to 5.5 V operation per its recommended conditions. Its TTL-compatible inputs require VIH ≥ 2.0 V and VIL ≤ 0.8 V, but internal pass-gate threshold and ron performance are optimized for 5-V VCC. Operating below 4.5 V risks increased on-resistance, timing violations, and potential functional failure. For 3.3-V systems, consider SN74CBTD3345DGVR or SN74LVC245APW instead.
Is the SN74CBT3345DGVR pin-compatible with the SN74LS245?
Yes, the SN74CBT3345DGVR uses the standard '245-type pinout: pins 1 (OE), 2–9 (A1–A8), 10 (GND), 11 (VCC), 12–19 (B1–B8), and 20 (OE) match the physical layout of SN74LS245 in SOIC-20. However, SN74CBT3345DGVR replaces tristate transceiver functionality with passive bidirectional switching-so while mechanical and pin-for-pin compatible, system-level logic (e.g., DIR control) must be re-evaluated.
What is the maximum signal frequency supported by the SN74CBT3345DGVR?
The SN74CBT3345DGVR does not specify a maximum clock or data rate directly, but its 0.25 ns propagation delay and 6 pF off-state I/O capacitance support clean signal transmission up to ≥100 MHz in properly terminated 50-Ω environments. Real-world bandwidth is limited by PCB trace impedance, load capacitance, and driver strength-not the switch itself-making it suitable for high-speed parallel buses including legacy PCI, ISA, and memory address/data paths.
Does the SN74CBT3345DGVR require external pull-up or pull-down resistors on its OE pins?
Yes-per TI's SCBA004 application report, all unused control inputs on the SN74CBT3345DGVR must be held at a defined logic level. OE should be pulled to GND (for always-on operation) or driven actively; OE should be pulled to VCC (for active-high enable) or driven. Floating OE/OE pins risk undefined switching states, increased ICC, and potential bus contention due to input threshold instability in TTL-compatible receivers.
SN74CBT3345DGVR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CBT
- Package/Case:
- 20-TFSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Bus Switch
- Circuit:
- 8 x 1:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- -
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TVSOP
SN74CBT3345DGVR FAQ
1.How can I place an order for SN74CBT3345DGVR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CBT3345DGVR 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 SN74CBT3345DGVR reliable?
The price and inventory of SN74CBT3345DGVR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT3345DGVR is usually 5 days.
3.What payment methods are accepted for SN74CBT3345DGVR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CBT3345DGVR transactions.
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4.How is shipping managed for SN74CBT3345DGVR?
SN74CBT3345DGVR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CBT3345DGVR 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 SN74CBT3345DGVR?
For technical support, including SN74CBT3345DGVR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3345DGVR requirements.
6.How does Aetrix verify that SN74CBT3345DGVR is sourced from the original manufacturer or authorized distributors?
All SN74CBT3345DGVR 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 SN74CBT3345DGVR meets industry standards.
7.What is the process for return or replacement of SN74CBT3345DGVR?
All SN74CBT3345DGVR units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3345DGVR, 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 SN74CBT3345DGVR part is unused and in its original packaging.
Return procedure for SN74CBT3345DGVR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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