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Texas Instruments SN74CBT3345DBR
- Part No.:
- SN74CBT3345DBR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74CBT3345DBR.pdf
- Description:
- IC BUS SWITCH 8 X 1:1 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,933
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Product details
Overview
SN74CBT3345DBR from Texas Instruments is an 8-bit high-speed TTL-compatible bus switch with dual output-enable control, 5-Ω on-state resistance, <0.25 ns propagation delay, and standard '245 pinout-used for bidirectional signal routing in memory expansion, FPGA I/O bridging, and hot-swap data path isolation.
For engineers reviewing the SN74CBT3345DBR datasheet, SN74CBT3345DBR pinout, SN74CBT3345DBR application, or SN74CBT3345DBR equivalent, key selection criteria include its dual OE logic control scheme, 4.5–5.5 V supply range, ±128 mA channel current rating, low capacitive loading (6 pF off-state), and SSOP-20 package compatibility with space-constrained PCB layouts.
Technical Context
The SN74CBT3345DBR implements a single 8-bit bidirectional analog switch bank using NMOS pass-gate architecture, enabling low-distortion signal transmission across A and B ports. Its dual OE inputs (active-low OE and active-high OE) provide flexible enable/disable logic without external inverters.
Operation requires VCC between 4.5 V and 5.5 V, supports TTL-level control inputs (VIH = 2 V, VIL = 0.8 V), and maintains high-impedance isolation when both OE conditions are unmet-ensuring clean signal blocking during power sequencing or fault recovery in mixed-voltage systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| On-state resistance (ron) | 5 Ω typical at VCC = 4.5 V - enables minimal voltage drop and signal attenuation in high-speed digital paths |
| Propagation delay (tpd) | 0.25 ns max at CL = 50 pF - supports >1 GHz signal switching without timing degradation |
| Supply voltage (VCC) | 4.5 V to 5.5 V - compatible with standard 5-V TTL and LVTTL logic domains |
| Channel current | ±128 mA continuous - sufficient for driving heavy capacitive loads or multiple fanouts |
| Off-state capacitance (Cio) | 6 pF - minimizes crosstalk and signal coupling between isolated ports |
| Input leakage current | ±1 µA max - ensures stable control input biasing without external pull resistors |
| Operating temperature | −40°C to +85°C - qualified for industrial-grade embedded and communications equipment |
Pinout & Package
SN74CBT3345DBR is housed in a 20-pin SSOP (Shrink Small Outline Package) with 0.65 mm pitch, 6.5 mm × 4.4 mm body size, and 1.2 mm max height-designed for automated SMT assembly and thermal performance up to 70°C/W junction-to-ambient.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OE) | Active-low output enable | Drives switch ON when low; used with OE to implement OR-style enable logic |
| 2–9 (A1–A8) | Port A input/output terminals | Bidirectional signal interface for upstream logic (e.g., microcontroller or ASIC) |
| 10 (GND) | Ground reference | Common return path for all internal circuitry and signal currents |
| 11 (VCC) | Power supply | 5-V supply input; decoupling capacitor required within 1 cm of this pin |
| 12–19 (B1–B8) | Port B input/output terminals | Bidirectional signal interface for downstream logic (e.g., memory or peripheral bus) |
| 20 (OE) | Active-high output enable | Drives switch ON when high; complements OE for flexible control mapping |
Key Features
| Feature | Design Value |
|---|---|
| Dual OE control logic | Eliminates need for external inverters-supports direct connection to microcontroller GPIOs with mixed polarity |
| 5-Ω low on-resistance | Reduces insertion loss below 0.1% for 3.3-V signals, preserving signal integrity in 50-Ω impedance environments |
| TTL-compatible inputs | Accepts standard 0.8 V / 2.0 V thresholds-interoperable with legacy 5-V logic without level shifters |
| High-impedance isolation | Guarantees >10⁹ Ω off-state resistance-prevents back-driving and leakage between powered/unpowered subsystems |
| Low dynamic power | 50 µA ICC max at 5.5 V-enables use in low-quiescent-power systems without thermal derating |
Applications
| Memory Expansion Interface | FPGA I/O Bridging |
|---|---|
|
Use Scenario: Expanding address/data bus width between a microcontroller and parallel SRAM or Flash memory. IC Role / Device Role / Timing Role: Bidirectional bus switch enabling time-multiplexed access to shared memory banks without contention. Use Value: Eliminates need for discrete transceivers or complex glue logic while maintaining sub-nanosecond timing margins. |
Use Scenario: Isolating FPGA configuration I/O from system management logic during partial reconfiguration. IC Role / Device Role / Timing Role: Signal path gate controlled by FPGA status signals to prevent metastability during bitstream load. Use Value: Provides deterministic high-Z state during configuration, avoiding bus conflicts and ensuring reliable JTAG/SPI programming. |
| Hot-Swap Data Path Isolation | Legacy System Voltage Translation |
|
Use Scenario: Safely inserting/removing peripheral cards in live 5-V backplane systems. IC Role / Device Role / Timing Role: Hot-swap buffer that disconnects data lines before power rail engagement. Use Value: Prevents inrush current and ground bounce by enforcing strict enable sequencing via dual OE control. |
Use Scenario: Interfacing 3.3-V ASIC outputs to 5-V legacy peripherals without level-shifter ICs. IC Role / Device Role / Timing Role: Passive voltage-tolerant switch leveraging 5-V tolerant I/O structure. Use Value: Supports mixed-voltage operation up to 5.5 V on all pins-no external clamping diodes required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus switching applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBTD3345DBR | Includes bus-hold circuitry on all I/O pins; higher ICC (100 µA); same pinout and ron | Preferred where floating inputs must be avoided without external pull resistors | Select when system lacks defined bus termination or operates in noisy ESD environments |
| SN74LVC245APWR | Octal non-inverting transceiver with 3-state outputs; 3.3-V only; no analog switch behavior | Requires separate direction control and does not support true bidirectional zero-delay switching | Choose only if level translation is primary need and timing-critical analog pass-through is unnecessary |
Compared with SN74CBT3345DBR, SN74CBTD3345DBR adds bus-hold functionality at the cost of higher quiescent current, while SN74LVC245APWR provides voltage translation but lacks the low-latency, bidirectional analog pass-through essential for high-speed bus sharing.
Availability
SN74CBT3345DBR is available at Aetrix Electronics and suitable for memory expansion, FPGA I/O bridging, hot-swap data path isolation, and legacy system voltage translation requiring stable component supply and long-term industrial lifecycle support.
Supply support for SN74CBT3345DBR 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 SN74CBT3345DBR belongs to TI's CBT (Crosspoint Bus Transceiver) family-designed specifically for high-speed, low-latency bidirectional signal routing in 5-V digital systems where timing predictability and signal fidelity are critical.
FAQ
What is the maximum operating voltage for SN74CBT3345DBR?
The SN74CBT3345DBR supports a supply voltage range of 4.5 V to 5.5 V under recommended conditions. Its absolute maximum rating allows VCC up to 7 V, but sustained operation above 5.5 V may compromise reliability and is not guaranteed per specification. All I/O pins tolerate −0.5 V to 7 V, enabling robust handling of transient overvoltage events without damage to the SN74CBT3345DBR.
How does the dual OE control logic work on SN74CBT3345DBR?
The SN74CBT3345DBR uses two independent output-enable inputs: OE (active-low) and OE (active-high). The switch connects port A to port B when either OE is low OR OE is high-functionally equivalent to an OR gate. When OE is high AND OE is low, the switch opens into high-impedance state. This design eliminates external inverters and simplifies control from microcontrollers with limited GPIO polarity options for the SN74CBT3345DBR.
Can SN74CBT3345DBR be used for analog signal switching?
Yes-the SN74CBT3345DBR is a true analog bus switch with NMOS pass-gate architecture, supporting bidirectional signal flow with flat frequency response up to 200 MHz. Its 5-Ω on-resistance and 6-pF off-capacitance make it suitable for low-distortion switching of analog audio, clock signals, or low-speed differential pairs-provided signal swing remains within the 0 V to VCC range and does not exceed the SN74CBT3345DBR's absolute maximum ratings.
What is the thermal performance of SN74CBT3345DBR in SSOP package?
The SN74CBT3345DBR in SSOP-20 (DB) package has a specified junction-to-ambient thermal resistance (θJA) of 70°C/W under JEDEC-standard board conditions. With a maximum power dissipation of ~15 mW (based on 50 µA ICC and 128 mA channel current), junction temperature rise remains under 1.1°C at full load-making thermal derating unnecessary in typical industrial ambient conditions for the SN74CBT3345DBR.
Is SN74CBT3345DBR RoHS compliant and lead-free?
Yes-SN74CBT3345DBR is RoHS compliant and features NiPdAu (NIPDAU) lead finish per TI's packaging documentation. It meets JEDEC Level-1 moisture sensitivity requirements and supports standard Pb-free reflow profiles up to 260°C peak temperature. The part marking "CU345" on the SN74CBT3345DBR device body confirms its compliance with environmental regulations for industrial and commercial applications.
SN74CBT3345DBR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CBT
- Package/Case:
- 20-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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-SSOP
SN74CBT3345DBR FAQ
1.How can I place an order for SN74CBT3345DBR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CBT3345DBR 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 SN74CBT3345DBR reliable?
The price and inventory of SN74CBT3345DBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT3345DBR is usually 5 days.
3.What payment methods are accepted for SN74CBT3345DBR?
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SN74CBT3345DBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CBT3345DBR 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 SN74CBT3345DBR?
For technical support, including SN74CBT3345DBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3345DBR requirements.
6.How does Aetrix verify that SN74CBT3345DBR is sourced from the original manufacturer or authorized distributors?
All SN74CBT3345DBR 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 SN74CBT3345DBR meets industry standards.
7.What is the process for return or replacement of SN74CBT3345DBR?
All SN74CBT3345DBR units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3345DBR, 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 SN74CBT3345DBR part is unused and in its original packaging.
Return procedure for SN74CBT3345DBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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