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Texas Instruments SN74CB3Q3345DBQR
- Part No.:
- SN74CB3Q3345DBQR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 20-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
SN74CB3Q3345DBQR.pdf
- Description:
- IC BUS SWITCH 8 X 1:1 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,735
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Product details
Overview
SN74CB3Q3345DBQR from Texas Instruments is an 8-bit FET bus switch optimized for high-bandwidth, low-voltage digital signal routing in 2.5-V/3.3-V systems. It delivers rail-to-rail switching (0–5 V), 4 Ω typical ON-state resistance, <0.2 ns propagation delay, and 5-V-tolerant I/Os with Ioff partial-power-down support - enabling bidirectional isolation in memory interleaving and bus isolation applications.
For engineers reviewing the SN74CB3Q3345DBQR datasheet, SN74CB3Q3345DBQR pinout, SN74CB3Q3345DBQR application, or SN74CB3Q3345DBQR equivalent, key selection criteria include its flat ron across voltage range, 20 MHz OE switching frequency, 4 pF OFF-state I/O capacitance, and SSOP-20 package compatibility with legacy board layouts requiring minimal redesign.
Technical Context
The SN74CB3Q3345DBQR integrates a charge-pump circuit to elevate gate voltage of pass transistors, ensuring low and flat ON-state resistance (ron = 4 Ω typ) across 0–5 V signal swing. Its dual OE inputs (active-high and active-low) enable flexible enable logic, supporting both synchronous and asynchronous bus gating.
Designed for signal integrity in high-speed digital paths, it features undervoltage clamp diodes on all data/control pins, 5-V-tolerant I/Os regardless of VCC state (2.3–3.6 V), and Ioff protection that blocks backflow current during partial power-down - critical for hot-swap and mixed-voltage system interoperability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2.3 V to 3.6 V - supports both 2.5-V and 3.3-V system rails without level-shifting. |
| ron (Typ) | 4 Ω - enables minimal voltage drop and near-zero propagation delay (<0.2 ns) in high-speed data paths. |
| Cio(OFF) | 4 pF typ - reduces capacitive loading and preserves signal edge integrity up to 500 MHz bandwidth. |
| fOE Max | 20 MHz - allows fast enable/disable cycling for dynamic bus arbitration and time-multiplexed routing. |
| Ioff | 1 µA max at VCC = 0 V - prevents damaging current flow between powered and unpowered domains during partial shutdown. |
| VI/O Range | 0 V to 5.5 V - permits seamless interfacing with 5-V legacy peripherals while operating from 2.5-V/3.3-V supply. |
| Propagation Delay | 0.12–0.2 ns - determined by ron × CL RC constant, suitable for sub-nanosecond timing-critical interconnects. |
Pinout & Package
SN74CB3Q3345DBQR is housed in a 20-pin SSOP (DBQ) package measuring 7.2 mm × 5.3 mm × 1.2 mm (max height), with 0.65 mm lead pitch and gull-wing leads. The package is RoHS-compliant, NIPDAU-finished, and rated MSL Level-2-260°C-1 year.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | OE / OE | Complementary output-enable inputs: OE high or OE low activates bidirectional A↔B path; both high/low disables switch. |
| 2–9 | A1–A8 | Input/output port A - connects to source-side bus (e.g., processor/memory interface). |
| 11–18 | B1–B8 | Input/output port B - connects to destination-side bus (e.g., peripheral or secondary memory bank). |
| 10 | GND | Ground reference for all internal circuitry and signal return path. |
| 20 | VCC | Primary power supply (2.3–3.6 V); powers charge pump and control logic. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail analog/digital switching | Supports 0–5 V signal swing with 3.3-V VCC - eliminates need for external level shifters in mixed-voltage systems. |
| Charge-pump-enhanced ron | Maintains flat 4 Ω ON-resistance across full VI/O range - ensures consistent timing and minimal insertion loss. |
| 5-V-tolerant I/Os with VCC off | Withstands 5 V on A/B pins even when VCC = 0 V - enables safe hot-plug operation and domain isolation. |
| Low OFF-state capacitance | 4 pF typ Cio(OFF) - minimizes crosstalk and signal distortion in dense PCB layouts and high-frequency buses. |
| Partial-power-down Ioff | 1 µA max leakage at VCC = 0 V - prevents backfeed current and protects upstream power domains during sleep states. |
Applications
| Memory Interleaving | Bus Isolation |
|---|---|
|
Use Scenario: Dual-channel DDR memory subsystem where address/data lines are dynamically routed between two memory banks. IC Role / Device Role / Timing Role: Bidirectional 8-bit bus switch enabling time-multiplexed access to separate memory banks without contention. Use Value: Sub-0.2 ns propagation delay and flat ron preserve setup/hold timing margins across 500 MHz data rates. |
Use Scenario: Isolating a microcontroller's peripheral bus from a hot-swappable module during insertion/removal. IC Role / Device Role / Timing Role: Signal gate that disconnects I/O paths when OE is deasserted, preventing glitch propagation and power domain coupling. Use Value: Ioff protection and 5-V-tolerant I/Os ensure no back-current flows into MCU during module power-up/down sequences. |
| Differential Signal Interface | Low-Distortion Signal Gating |
|
Use Scenario: Routing LVDS or RSDS clock/data pairs through shared trace resources in FPGA-based video processing systems. IC Role / Device Role / Timing Role: Low-capacitance (4 pF), low-ron switch preserving differential pair impedance and common-mode rejection. Use Value: Near-zero skew and minimal added jitter enable clean clock distribution across multiple parallel channels. |
Use Scenario: Enabling/disabling analog sensor signals (e.g., audio ADC inputs) under software control without signal degradation. IC Role / Device Role / Timing Role: Analog-capable FET switch providing rail-to-rail conduction with negligible THD and flat frequency response. Use Value: 4 Ω ron and 4 pF Cio(OFF) maintain >90 dB SNR up to 100 MHz, supporting wideband sensor front-ends. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET bus switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBT3345DBQR | Higher ron (7 Ω typ), no charge pump, 3.3-V only VCC range (4.5–5.5 V not supported). | Lacks 5-V-tolerant I/Os with VCC off; unsuitable for hot-swap or partial-power-down use cases. | Choose only if system operates strictly at 3.3 V and does not require Ioff or 5-V signaling. |
| SN74LVC1G3157DBVR | Single-channel SPDT switch, 6 Ω ron, 3.3-V VCC only, no dual-OE control, 5-V-tolerant but no Ioff spec. | Not pin-compatible; requires 8× instantiation for 8-bit function, increasing layout area and BOM count. | Select for low-channel-count applications where space allows discrete channel replication and Ioff is not required. |
Compared with SN74CB3Q3345DBQR, SN74CBT3345DBQR offers lower cost but sacrifices 5-V tolerance during power-down, while SN74LVC1G3157DBVR provides flexibility for non-parallel routing but incurs significant area and complexity overhead for 8-bit bus functions.
Availability
SN74CB3Q3345DBQR is available at Aetrix Electronics and suitable for memory interleaving, bus isolation, differential signal interface, and low-distortion signal gating applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant manufacturing.
Supply support for SN74CB3Q3345DBQR 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-speed interface solutions.
The SN74CB3Q3345DBQR belongs to TI's CB3Q family of high-bandwidth FET bus switches, designed specifically for low-latency, low-distortion signal routing in broadband communications, networking infrastructure, and data-intensive computing platforms.
FAQ
What is the maximum signal frequency supported by the SN74CB3Q3345DBQR?
The SN74CB3Q3345DBQR supports signal bandwidth up to 500 MHz due to its low 4 pF OFF-state I/O capacitance and flat 4 Ω ON-state resistance. This performance is validated under typical conditions (VCC = 3.3 V, TA = 25°C) and enables clean signal transmission in high-speed digital buses such as memory interfaces and FPGA interconnects. Bandwidth may vary slightly with load and PCB layout.
Does the SN74CB3Q3345DBQR support hot-swap operation?
Yes, the SN74CB3Q3345DBQR supports hot-swap operation via its 5-V-tolerant I/Os and Ioff protection. When VCC is 0 V, the device blocks back-current flow (Ioff ≤ 1 µA) and withstands up to 5.5 V on A/B pins - allowing safe insertion/removal in live backplanes or modular systems without disrupting upstream power domains.
What is the recommended pull-up/pull-down configuration for OE and OE on the SN74CB3Q3345DBQR?
TI recommends tying OE to VCC through a pull-up resistor and OE to GND through a pull-down resistor to ensure defined high-impedance state during power-up/power-down. Minimum resistor values depend on driver strength; for standard CMOS drivers, 10 kΩ is typical. This prevents undefined switching states and avoids bus contention before firmware initialization.
Can the SN74CB3Q3345DBQR be used for analog signal switching?
Yes, the SN74CB3Q3345DBQR supports analog signal switching due to its rail-to-rail conduction (0–5 V), low 4 Ω ron, and flat resistance profile. It maintains signal fidelity for audio, sensor, and clock signals up to 100 MHz. However, it is not specified for ultra-low THD or precision DC accuracy - verify linearity and leakage in final application.
Is the SN74CB3Q3345DBQR pin-compatible with other packages in the same family?
No - the SN74CB3Q3345DBQR (SSOP-20) shares identical logic and pin function mapping with SN74CB3Q3345PWR (TSSOP-20) and SN74CB3Q3345RGYR (VQFN-20), but mechanical dimensions, thermal pad requirements, and soldering profiles differ. Board layout must be adapted per package; no direct footprint interchangeability exists without redesign.
SN74CB3Q3345DBQR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CB
- Package/Case:
- 20-SSOP (0.154", 3.90mm 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:
- 2.3V ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SSOP
SN74CB3Q3345DBQR FAQ
1.How can I place an order for SN74CB3Q3345DBQR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CB3Q3345DBQR 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 SN74CB3Q3345DBQR reliable?
The price and inventory of SN74CB3Q3345DBQR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CB3Q3345DBQR is usually 5 days.
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Once your SN74CB3Q3345DBQR 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 SN74CB3Q3345DBQR?
For technical support, including SN74CB3Q3345DBQR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CB3Q3345DBQR requirements.
6.How does Aetrix verify that SN74CB3Q3345DBQR is sourced from the original manufacturer or authorized distributors?
All SN74CB3Q3345DBQR 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 SN74CB3Q3345DBQR meets industry standards.
7.What is the process for return or replacement of SN74CB3Q3345DBQR?
All SN74CB3Q3345DBQR units undergo pre-shipment inspection (PSI). If there is an issue with SN74CB3Q3345DBQR, 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 SN74CB3Q3345DBQR part is unused and in its original packaging.
Return procedure for SN74CB3Q3345DBQR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74CB3Q3345DBQR Tags
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SN74HC138DR
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