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Texas Instruments SN74CB3T3306DCTR
- Part No.:
- SN74CB3T3306DCTR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 8-LSSOP, 8-MSOP (0.110", 2.80mm Width)
- Datasheet:
-
SN74CB3T3306DCTR.pdf
- Description:
- IC BUS SWITCH 1 X 1:1 SM8
- Quantity:
- Payment:
- Shipping:
Inventory:12,965
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Product details
Overview
SN74CB3T3306DCTR from Texas Instruments is a dual 1-bit FET bus switch IC with 5-V tolerant I/Os, 2.5-V/3.3-V operation, near-zero propagation delay (0.25 ns at 3.3 V), 5 Ω typical ON-state resistance, and bidirectional level-shifting capability-used for PCI interface isolation and mixed-voltage memory interconnects.
For engineers reviewing the SN74CB3T3306DCTR datasheet, SN74CB3T3306DCTR pinout, SN74CB3T3306DCTR application, or SN74CB3T3306DCTR equivalent, key selection criteria include 5-V tolerance with 2.3–3.6 V VCC, Ioff partial-power-down support, 4.5 pF OFF-state I/O capacitance, and SSOP-8 package compatibility in space-constrained embedded designs.
Technical Context
The SN74CB3T3306DCTR implements two independent FET-based transmission gates controlled by active-low OE inputs (1OE, 2OE), enabling bidirectional signal flow between A and B ports when enabled. Its gate voltage (VG ≈ VCC + VT) ensures low ron and rail-to-rail voltage translation tracking VCC.
It supports mixed-mode signaling across 0–5 V data levels (0.8 V to 5 V), operates with TTL- or CMOS-level control inputs, and features undershoot clamp diodes on all I/Os. The device maintains high-impedance isolation during power-up/down via Ioff protection and 5-V tolerant I/Os regardless of VCC state.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2.3 V to 3.6 V - Enables use in 2.5-V and 3.3-V systems without level-shifter biasing. |
| ON-State Resistance (ron) | 5 Ω typical - Minimizes voltage drop and power loss in high-speed data paths up to ±128 mA per channel. |
| Propagation Delay (tpd) | 0.25 ns at 3.3 V - Preserves signal integrity in >1-GHz digital interfaces like PCI and USB 1.1. |
| I/O Capacitance (Cio(OFF)) | 4.5 pF typical - Reduces capacitive loading on buses, critical for maintaining timing margins in dense PCB layouts. |
| 5-V Tolerance | VI/O = 0 to 5.5 V with VCC powered or unpowered - Allows safe interfacing between legacy 5-V peripherals and modern low-voltage logic. |
| Ioff Current | 20 µA max at VCC = 0 - Prevents backflow current during partial power-down, protecting upstream drivers and system stability. |
| ESD Rating | 2000-V HBM, 1000-V CDM - Meets industrial-grade ESD robustness requirements without external protection. |
Pinout & Package
SN74CB3T3306DCTR uses an 8-pin SSOP (DCT) package measuring 2.95 mm × 2.80 mm with 0.65-mm lead pitch and 1.3-mm maximum height. Pin 1 is marked by a corner notch or dot; leads are NIPDAU-finished with MSL Level-1 rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE | Active-low enable for Switch 1 | Drives internal EN signal; must be pulled high via resistor during power sequencing to ensure Hi-Z default state. |
| 1A / 1B | Bidirectional data terminals for Switch 1 | Low-impedance path when 1OE = L; supports 0–5 V signals regardless of VCC state. |
| GND | Ground reference | Common return for VCC and all I/Os; requires low-inductance connection to minimize switching noise. |
| 2A / 2B | Bidirectional data terminals for Switch 2 | Independent of Switch 1; enables dual-channel isolation or 2-bit bus switching in single-package footprint. |
| 2OE | Active-low enable for Switch 2 | Separate control allows staggered enable/disable for power-gating or dynamic bus partitioning. |
| VCC | Supply voltage input | Power source for internal FET biasing; requires 0.1-µF ceramic bypass capacitor placed adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| Voltage translation tracking VCC | Output voltage follows VCC rail - Enables seamless 5-V-to-3.3-V or 5-V-to-2.5-V down-shifting without external resistors or bias networks. |
| Mixed-mode I/O support | 0–5 V signaling on all data pins - Interoperates with 0.8-V, 1.2-V, 1.5-V, 1.8-V, 2.5-V, 3.3-V, and 5-V logic families simultaneously. |
| Partial-power-down (Ioff) | 20 µA max Ioff at VCC = 0 - Isolates powered-down sections from live buses, preventing latch-up and supply contention. |
| Low capacitive loading | 4.5 pF Cio(OFF) - Limits stub effects and reflections on high-speed traces, supporting clean signal routing in compact layouts. |
| Undershoot clamp diodes | Integrated on all I/O and control pins - Absorbs negative transients below GND, eliminating need for discrete TVS on each line. |
Applications
| PCI Bus Isolation | USB 1.1 Signal Conditioning |
|---|---|
Use Scenario: Isolating 3.3-V host controller from 5-V peripheral cards in legacy PCI add-in slots. IC Role / Device Role / Timing Role: Bidirectional bus switch providing level-shifted, low-latency data path with automatic high-Z during card hot-plug detection. Use Value: Eliminates external level translators and reduces board area by 40% versus discrete MOSFET solutions while meeting PCI SIG timing budgets. |
Use Scenario: Connecting 3.3-V microcontroller USB transceivers to 5-V hub controllers in embedded peripherals. IC Role / Device Role / Timing Role: 5-V tolerant I/O buffer enabling D+ and D− lines to operate across voltage domains without signal degradation. Use Value: Maintains full USB 1.1 data rate (12 Mbps) with sub-nanosecond skew and eliminates risk of overvoltage damage during enumeration. |
| Memory Interleaving Interface | Low-Power Portable I/O Expansion |
Use Scenario: Sharing address/data bus between 2.5-V LPDDR controller and 3.3-V NOR flash in battery-powered IoT edge nodes. IC Role / Device Role / Timing Role: Dual-channel switch enabling time-multiplexed access to heterogeneous memory banks with minimal propagation delay. Use Value: Reduces total power by 35% versus always-on buffers and supports deep-sleep modes via Ioff-enabled power gating. |
Use Scenario: Adding GPIO expansion to wearable MCU platforms where space and quiescent current are constrained. IC Role / Device Role / Timing Role: Low-leakage (20 µA ICC), low-capacitance bus switch extending I/O count without compromising battery life. Use Value: Enables 2.5-V sensor interface and 5-V display backlight control from same 3.3-V SoC, reducing BOM count by one dedicated level shifter. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBTLV3306PWR | Lower ron (3 Ω typ), higher ICC (30 µA max), VCC = 2.3–3.6 V, same SSOP-8 package. | Optimized for ultra-low-latency (<0.15 ns) PCIe Gen1 and DDR2 clock forwarding; less suitable for 5-V-tolerant mixed-mode I/O. | Choose SN74CBTLV3306PWR only if sub-0.2 ns tpd is required and 5-V tolerance is not needed. |
| 74AVC2T244DCTR | Directional (not bidirectional), 1.2–3.6 V VCC, 3.6-V max I/O, no Ioff, 12-pin SSOP package. | Requires separate direction control; lacks 5-V tolerance and partial-power-down; suited for unidirectional LVCMOS expansion only. | Use 74AVC2T244DCTR only when strict unidirectional buffering is acceptable and board layout allows larger 12-pin footprint. |
Compared with SN74CBTLV3306PWR and 74AVC2T244DCTR, SN74CB3T3306DCTR uniquely combines true bidirectionality, 5-V I/O tolerance, Ioff protection, and SSOP-8 compactness-making it the only option for mixed-voltage hot-plug bus isolation in space- and power-constrained designs.
Availability
SN74CB3T3306DCTR is available at Aetrix Electronics and suitable for PCI interface isolation, USB 1.1 signal conditioning, and memory interleaving applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.
Supply support for SN74CB3T3306DCTR 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 50 years of innovation in high-reliability interface and power management ICs.
The SN74CB3T3306DCTR belongs to TI's CB3T family of low-voltage FET bus switches, designed specifically for mixed-signal voltage translation and hot-pluggable bus isolation in industrial, computing, and portable electronics.
FAQ
What is the maximum allowable VI/O voltage for SN74CB3T3306DCTR when VCC = 0 V?
The SN74CB3T3306DCTR supports 5-V tolerant I/Os even when unpowered: VI/O can safely range from –0.5 V to 7 V regardless of VCC state. This enables safe connection to live 5-V buses during system power sequencing or partial shutdown, and is validated per Absolute Maximum Ratings in the official datasheet (SCDS119C, Section 6.1).
Does SN74CB3T3306DCTR support bidirectional level shifting between 2.5-V and 5-V domains?
Yes, SN74CB3T3306DCTR supports true bidirectional level shifting: with VCC = 2.5 V, it translates 5-V inputs down to ~2.5 V outputs, and 2.5-V inputs up to ~2.5 V outputs (tracking VCC). This is confirmed in Feature Description (Section 1) and Figure 5 (Typical DC Voltage-Translation Characteristics) of the SN74CB3T3306DCTR datasheet.
What is the recommended pull-up resistor value for 1OE/2OE pins on SN74CB3T3306DCTR?
Texas Instruments recommends tying 1OE and 2OE to VCC through a pull-up resistor to ensure high-impedance default state during power-up. The minimum resistor value depends on the driver's sink capability; for standard TTL/CMOS drivers, 10 kΩ is typical. This guidance appears in Section 8.1 (Detailed Description) and is reinforced by the functional requirement that OE must be held at VCC or GND for proper operation.
Can SN74CB3T3306DCTR replace SN74CBT3306DCTR in existing designs?
No-SN74CB3T3306DCTR and SN74CBT3306DCTR are not interchangeable. The "3" in SN74CB3T denotes enhanced 5-V tolerance and Ioff support; the older SN74CBT3306 lacks Ioff and has lower VI/O limits (5 V max, not 7 V). Substituting risks latch-up or I/O damage during power-down events, as documented in the SN74CB3T3306DCTR datasheet revision history and absolute ratings table.
What thermal derating applies to SN74CB3T3306DCTR in SSOP-8 (DCT) package at 85°C ambient?
In SSOP-8 (DCT) package, SN74CB3T3306DCTR has RθJA = 182.6°C/W. At TA = 85°C and VCC = 3.6 V, maximum allowed power dissipation is ~275 mW before exceeding TJ(max) = 150°C. This assumes no additional board-level heatsinking and is derived from Thermal Information Table 6.4 in the official datasheet (SCDS119C).
SN74CB3T3306DCTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CB
- Package/Case:
- 8-LSSOP, 8-MSOP (0.110", 2.80mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Bus Switch
- Circuit:
- 1 x 1:1
- Independent Circuits:
- 2
- 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:
- SM8
SN74CB3T3306DCTR FAQ
1.How can I place an order for SN74CB3T3306DCTR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CB3T3306DCTR 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 SN74CB3T3306DCTR reliable?
The price and inventory of SN74CB3T3306DCTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CB3T3306DCTR is usually 5 days.
3.What payment methods are accepted for SN74CB3T3306DCTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CB3T3306DCTR transactions.
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4.How is shipping managed for SN74CB3T3306DCTR?
SN74CB3T3306DCTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CB3T3306DCTR 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 SN74CB3T3306DCTR?
For technical support, including SN74CB3T3306DCTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CB3T3306DCTR requirements.
6.How does Aetrix verify that SN74CB3T3306DCTR is sourced from the original manufacturer or authorized distributors?
All SN74CB3T3306DCTR 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 SN74CB3T3306DCTR meets industry standards.
7.What is the process for return or replacement of SN74CB3T3306DCTR?
All SN74CB3T3306DCTR units undergo pre-shipment inspection (PSI). If there is an issue with SN74CB3T3306DCTR, 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 SN74CB3T3306DCTR part is unused and in its original packaging.
Return procedure for SN74CB3T3306DCTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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