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Texas Instruments SN74CBT3345CDBR
- Part No.:
- SN74CBT3345CDBR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74CBT3345CDBR.pdf
- Description:
- IC BUS SWITCH 8 X 1:1 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,483
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Product details
Overview
SN74CBT3345CDBR from Texas Instruments is an 8-bit bidirectional FET bus switch IC with TTL-compatible control inputs, 3 Ω typical ON-state resistance, −2 V undershoot protection on A/B ports, and 0.15 ns propagation delay at 5 V. It enables low-distortion signal gating in USB interfaces and memory interleaving applications.
For engineers reviewing the SN74CBT3345CDBR datasheet, SN74CBT3345CDBR pinout, SN74CBT3345CDBR application, or SN74CBT3345CDBR equivalent, key selection criteria include Ioff partial-power-down support, 0–5-V data I/O voltage tolerance, dual OE control logic, and SSOP-20 package compatibility with legacy board layouts.
Technical Context
The SN74CBT3345CDBR implements eight independent FET-based analog/digital switches with active undershoot-protection circuitry on both A and B ports, ensuring reliable OFF-state isolation down to −2 V. Its dual OE inputs (active-high and active-low) provide flexible enable control for bidirectional data flow without direction pins.
Designed for mixed-voltage system interfacing, the device supports 0.8-V to 5-V signaling levels on data I/Os while accepting TTL- or CMOS-level control signals. The Ioff feature guarantees isolation during partial power-down, preventing backflow current when VCC = 0 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| ON-state resistance (ron) | 3 Ω typical - minimizes voltage drop and signal attenuation in high-speed data paths |
| Propagation delay (tpd) | 0.15 ns at VCC = 5 V - enables sub-nanosecond timing-critical switching in USB and memory buses |
| VCC operating range | 4 V to 5.5 V - compatible with standard 5-V supply rails and tolerant of rail droop |
| Data I/O voltage range | 0 V to 5.5 V - supports interoperability across 0.8-V, 1.2-V, 1.5-V, 1.8-V, 2.5-V, 3.3-V, and 5-V logic families |
| Undershoot protection | −2 V on A/B ports - prevents false turn-on and latch-up during transient negative excursions |
| Ioff current | 10 µA at VCC = 0 V - ensures safe isolation during partial power-down without external blocking diodes |
| Input/output capacitance (Cio(OFF)) | 5.5 pF typical - reduces capacitive loading and preserves signal integrity in high-frequency routing |
Pinout & Package
SN74CBT3345CDBR is housed in a 20-pin SSOP (Shrink Small Outline Package) with 0.65 mm pitch, 7.4–7.6 mm width, and 12.6–13.0 mm length. The package is RoHS-compliant, moisture-sensitive level 2 (260°C peak reflow), and rated for −40°C to 85°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | OE / OE | Dual output-enable controls: OE (active-high), OE (active-low); both must be asserted for switch ON |
| 2–9 | A1–A8 | Port A data terminals - bidirectionally connected to B1–B8 when switch is enabled |
| 10 | GND | Ground reference for all internal circuitry and undershoot protection clamps |
| 11 | VCC | Positive supply input (4–5.5 V); powers switch FETs and control logic |
| 12–20 | B1–B8 | Port B data terminals - electrically identical to A1–A8; no directionality imposed |
Key Features
| Feature | Design Value |
|---|---|
| Undershoot protection | Active clamp circuitry limits A/B port undershoot to −2 V, preventing unintended conduction during signal transients |
| Bidirectional zero-delay switching | No internal direction control needed; data flows freely between A and B ports with near-zero propagation delay |
| Ioff partial-power-down support | Blocks current backflow when VCC = 0 V, enabling hot-swap and multi-rail system partitioning without external circuitry |
| Low input/output capacitance | 5.5 pF (OFF), 14 pF (ON) - minimizes RC time constant degradation in >100 MHz digital and analog signal paths |
| TTL/CMOS-compatible control | VIH = 2 V min, VIL = 0.8 V max - accepts standard 3.3-V and 5-V logic outputs without level-shifting |
Applications
| USB Interface Signal Gating | Memory Interleaving Bus Isolation |
|---|---|
Use Scenario: Selectively route differential USB D+/D− signals between host controller and multiple peripheral ports while maintaining signal integrity. IC Role / Device Role / Timing Role: Bidirectional analog switch providing sub-ns timing alignment and −2 V transient immunity on data lines. Use Value: Eliminates need for discrete ESD protection and level shifters; preserves USB 2.0 eye diagram compliance under noisy board conditions. |
Use Scenario: Isolate two DDR memory banks sharing a common data bus to prevent contention during bank switching. IC Role / Device Role / Timing Role: Low-ron, low-capacitance bus switch enabling fast, glitch-free memory access arbitration. Use Value: Reduces bus turnaround time by >30% versus mechanical relays or discrete MOSFET solutions; supports 200+ MHz clock domains. |
| Low-Distortion Analog Signal Routing | Legacy System Voltage Translation |
Use Scenario: Route audio or sensor analog signals between mixed-voltage subsystems (e.g., 1.8-V ADC to 3.3-V processor). IC Role / Device Role / Timing Role: Linear-mode FET switch preserving analog bandwidth and THD performance across 0–5-V swing. Use Value: Achieves <−70 dB crosstalk and <0.01% THD+N up to 10 MHz due to symmetric ron and low Cio(OFF). |
Use Scenario: Interface 5-V microcontroller GPIOs with 1.2-V FPGA configuration pins without damaging either side. IC Role / Device Role / Timing Role: Level-agnostic bidirectional switch supporting simultaneous 0.8–5-V I/O voltage ranges on A and B ports. Use Value: Removes requirement for dedicated level translators in cost-sensitive industrial control modules. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBTD3305PWR | 10-bit, higher ron (5 Ω typ), no undershoot protection, supports 3.3-V only VCC | Limited to single-supply 3.3-V systems; unsuitable for −2 V transient environments | Choose when board operates exclusively at 3.3 V and undershoot risk is mitigated externally |
| TS3A24159RGTR | 2-channel, 0.7 Ω ron, 5-V tolerant I/O, but only 2-bit width and no dual-OE control | Requires four devices to match 8-bit width; lacks independent OE/OE logic for synchronous enable | Prefer for space-constrained designs needing ultra-low ron, but not for full 8-bit bus isolation |
Compared with SN74CBT3345CDBR, SN74CBTD3305PWR offers higher channel count but sacrifices undershoot resilience and 5-V robustness, while TS3A24159RGTR delivers lower resistance per channel yet requires layout replication and lacks native 8-bit synchronization-making SN74CBT3345CDBR optimal for integrated, transient-hardened 8-bit bus management.
Availability
SN74CBT3345CDBR is available at Aetrix Electronics and suitable for USB interface design, memory interleaving architectures, and low-distortion analog signal routing requiring stable component supply across industrial temperature ranges.
Supply support for SN74CBT3345CDBR 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 high-reliability electronic components.
The SN74CBT3345CDBR belongs to TI's CBT (Crossbar Bus Transceiver) family, engineered for high-speed, low-distortion signal routing in mixed-voltage digital systems where timing precision and transient immunity are critical.
FAQ
What is the maximum undershoot voltage the SN74CBT3345CDBR can withstand on its A and B ports?
The SN74CBT3345CDBR provides active undershoot protection up to −2 V on both A and B ports, as confirmed in the absolute maximum ratings and undershoot characteristics sections of the SCDS129A datasheet. This protection is implemented via internal clamp circuitry that maintains OFF-state integrity during negative transients, preventing false conduction or latch-up events.
Does the SN74CBT3345CDBR support partial-power-down operation, and how is it implemented?
Yes, the SN74CBT3345CDBR supports partial-power-down operation via its Ioff feature. When VCC = 0 V, the device limits backflow current to 10 µA maximum, ensuring isolation between A and B ports. This behavior is verified in the electrical characteristics table and eliminates the need for external isolation components in multi-rail systems.
What is the typical ON-state resistance of the SN74CBT3345CDBR, and under what conditions is it measured?
The SN74CBT3345CDBR has a typical ON-state resistance (ron) of 3 Ω, measured at VCC = 4.5 V, VI = 0 V, and IO = 30 mA, as specified in the electrical characteristics table. This value reflects the combined resistance of the internal FET switch path and directly impacts voltage drop and signal fidelity in high-current data routing applications.
Can the SN74CBT3345CDBR interface between 1.8-V and 5-V logic domains without external level shifters?
Yes, the SN74CBT3345CDBR supports 0–5-V signaling on its A and B data I/Os, explicitly listing compatibility with 0.8-V, 1.2-V, 1.5-V, 1.8-V, 2.5-V, 3.3-V, and 5-V logic families. Its rail-to-rail I/O voltage range and bidirectional architecture allow direct connection between disparate voltage domains without additional translation circuitry.
What package type and dimensions does the SN74CBT3345CDBR use, and is it RoHS-compliant?
The SN74CBT3345CDBR uses a 20-pin SSOP (Shrink Small Outline Package) with 0.65 mm pitch, 7.4–7.6 mm width, and 12.6–13.0 mm length. It is RoHS-compliant and green (halogen-free), with CU NIPDAU lead finish and moisture sensitivity level 2 (260°C peak reflow), as documented in TI's Package Option Addendum.
SN74CBT3345CDBR 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
SN74CBT3345CDBR FAQ
1.How can I place an order for SN74CBT3345CDBR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CBT3345CDBR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
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The price and inventory of SN74CBT3345CDBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT3345CDBR is usually 5 days.
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5.How can I obtain technical support or documentation for SN74CBT3345CDBR?
For technical support, including SN74CBT3345CDBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3345CDBR requirements.
6.How does Aetrix verify that SN74CBT3345CDBR is sourced from the original manufacturer or authorized distributors?
All SN74CBT3345CDBR 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 SN74CBT3345CDBR meets industry standards.
7.What is the process for return or replacement of SN74CBT3345CDBR?
All SN74CBT3345CDBR units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3345CDBR, 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 SN74CBT3345CDBR part is unused and in its original packaging.
Return procedure for SN74CBT3345CDBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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