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Texas Instruments SN74CBTD3306DR
- Part No.:
- SN74CBTD3306DR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74CBTD3306DR.pdf
- Description:
- IC BUS SWITCH 1 X 1:1 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,553
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Product details
Overview
SN74CBTD3306DR from Texas Instruments is a dual FET bus switch with integrated level-shifting capability, designed for bidirectional signal routing between 5-V and 3.3-V logic domains. It features 5-Ω on-state resistance, TTL-compatible control inputs, and built-in diode-based level shifting from 5-V inputs to 3.3-V outputs. Used in mixed-voltage system interconnects such as memory address/data buses and peripheral I/O expansion.
For engineers reviewing the SN74CBTD3306DR datasheet, SN74CBTD3306DR pinout, SN74CBTD3306DR application, or SN74CBTD3306DR equivalent, key selection criteria include on-resistance matching, level-shift directionality (5V→3.3V only), OE-controlled bidirectional switching, and SOIC-8 thermal performance at −40°C to 85°C.
Technical Context
This device implements two independent NMOS transmission-gate switches, each controlled by a dedicated active-low output-enable (OE) input. Switch conduction occurs when OE is low, establishing a low-impedance path between A and B ports with no internal directionality - signal flow is fully bidirectional.
Level shifting is achieved via integrated clamp diodes to VCC, enabling 5-V-tolerant inputs while driving 3.3-V-compatible outputs. The architecture does not support reverse-level shifting (3.3-V-to-5-V), and operation at high edge rates or with large capacitive loads may reduce effective voltage translation fidelity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| On-state resistance (ron) | 5 Ω typical at VCC = 4.5 V - ensures minimal voltage drop and signal integrity for ≤30 mA channel current |
| Supply voltage range (VCC) | 4.5 V to 5.5 V - compatible with standard 5-V logic rails and tolerant of ±5% regulation variation |
| Input voltage range (VI) | −0.5 V to 7 V - supports 5-V-tolerant inputs with integrated clamping diodes |
| Propagation delay (tpd) | 0.25 ns typical - enables use in high-speed digital interfaces up to ~1 GHz bandwidth (RC-limited) |
| Off-state capacitance (Cio(OFF)) | 4 pF - minimizes capacitive loading on disabled signal paths during bus isolation |
| Control input capacitance (Ci) | 3 pF - reduces dynamic power consumption and timing skew on OE control lines |
| Operating temperature | −40°C to 85°C - qualified for industrial-grade embedded systems and peripheral interface modules |
Pinout & Package
SN74CBTD3306DR is housed in an 8-pin SOIC (D) package with 1.27 mm lead pitch, 3.9 mm body width, and 1.75 mm maximum height. Pin 1 is marked by a beveled corner or notch; the package is RoHS-compliant and rated MSL-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (1OE) | Channel 1 output-enable input | Active-low control: drives channel 1 (1A↔1B) into high-impedance state when high |
| 2 (1A) | Channel 1 port A terminal | Bidirectional signal node - connects to 5-V domain in level-shifting configurations |
| 3 (1B) | Channel 1 port B terminal | Bidirectional signal node - connects to 3.3-V domain; output voltage clamped by VCC diode |
| 4 (GND) | Ground reference | Return path for all internal circuitry and substrate bias; must be low-impedance |
| 5 (2OE) | Channel 2 output-enable input | Independent active-low control for second switch; no cross-talk with 1OE |
| 6 (2A) | Channel 2 port A terminal | Second bidirectional node - electrically identical to 1A; supports parallel bus extension |
| 7 (2B) | Channel 2 port B terminal | Second bidirectional node - electrically identical to 1B; shares same VCC clamp structure |
| 8 (VCC) | Positive supply | 5-V rail connection; supplies internal clamp diodes and gate drive; bypass capacitor required |
Key Features
| Feature | Design Value |
|---|---|
| 5-Ω low on-resistance | Minimizes insertion loss and maintains signal rise/fall times across 50-Ω transmission lines |
| TTL-compatible OE inputs | Accepts standard 5-V logic thresholds (VIL ≤ 0.8 V, VIH ≥ 2 V) without external level translation |
| Integrated VCC-clamp diodes | Enables safe 5-V input operation while sourcing 3.3-V-compatible output levels without external components |
| 0.25-ns propagation delay | Supports high-speed data multiplexing in DDR memory buffers and FPGA I/O expansion paths |
| 4-pF off-state capacitance | Reduces crosstalk and maintains isolation between enabled/disabled channels in dense PCB layouts |
Applications
| Memory Address Bus Isolation | FPGA I/O Voltage Translation |
|---|---|
Use Scenario: Isolating address lines between a 5-V microcontroller and 3.3-V SRAM during power-down sequencing. IC Role / Device Role / Timing Role: Bidirectional bus switch enabling/disabling address propagation with sub-nanosecond timing control. Use Value: Prevents back-driving of unpowered 3.3-V memory while maintaining full-speed access during active operation. |
Use Scenario: Interfacing 5-V legacy peripherals to a 3.3-V FPGA I/O bank requiring level-adapted control signals. IC Role / Device Role / Timing Role: Level-shifting bus switch providing 5-V-tolerant inputs and 3.3-V-compatible outputs with matched propagation delay. Use Value: Eliminates need for discrete resistor-divider or dedicated level translators on multiple control lines. |
| PCI/ISA Bus Signal Multiplexing | Industrial Sensor Interface Hub |
Use Scenario: Sharing a single 5-V data bus among multiple 3.3-V sensor ADCs using time-multiplexed access. IC Role / Device Role / Timing Role: Dual-channel switch enabling time-sliced bidirectional communication with independent OE control per channel. Use Value: Reduces PCB layer count by consolidating two independent bus segments into one physical trace set. |
Use Scenario: Aggregating analog sensor outputs conditioned at 5-V into a 3.3-V ADC subsystem with shared reference and clock. IC Role / Device Role / Timing Role: Signal-routing switch isolating sensor excitation lines from measurement paths during sampling windows. Use Value: Prevents ground loop coupling and ensures clean 3.3-V ADC input compliance without additional op-amp buffering. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus-switching applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBT3244D | Octal non-inverting bus switch; no integrated level-shifting diodes; requires external 3.3-V pull-ups for 5-V compatibility | Suitable for pure 3.3-V or 5-V-only systems; lacks native 5V→3.3V translation | Select when higher channel count is needed and level shifting is handled elsewhere in the signal chain |
| SN74AVC4T245PW | 4-bit dual-supply translator with separate VCCA/VCCB; supports bidirectional 3.3V↔5V translation; higher static current (10 μA vs. 1.5 mA) | Enables true bidirectional level shifting in both directions; requires two supply rails | Select when reverse translation (3.3V→5V) or tighter voltage tolerance is required |
Compared with SN74CBTD3306DR, SN74CBT3244D offers more channels but no level shifting, while SN74AVC4T245PW provides full bidirectional translation at the cost of dual-supply complexity and higher quiescent current - SN74CBTD3306DR remains optimal for unidirectional 5V→3.3V bus isolation with minimal BOM impact.
Availability
SN74CBTD3306DR is available at Aetrix Electronics and suitable for industrial control interfaces, FPGA I/O expansion, and mixed-voltage memory subsystems requiring stable component supply across extended temperature ranges.
Supply support for SN74CBTD3306DR 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 logic solutions, with over 90 years of innovation in industrial, automotive, and communications markets.
The SN74CBTD3306DR belongs to TI's 74CBT family of advanced bus switches, engineered specifically for low-distortion, high-speed signal routing in mixed-voltage digital systems where level translation and minimal propagation delay are critical.
FAQ
What is the primary function of the SN74CBTD3306DR in a digital system?
The SN74CBTD3306DR functions as a dual bidirectional FET bus switch that enables or isolates signal paths between two logic domains. Its core role is to provide low-resistance (5 Ω typical), sub-nanosecond switching between 5-V and 3.3-V interfaces - specifically translating 5-V inputs down to 3.3-V-compatible outputs using on-chip clamp diodes. This makes SN74CBTD3306DR ideal for memory bus isolation, FPGA I/O bridging, and peripheral interface consolidation where voltage domain boundaries exist.
Can the SN74CBTD3306DR perform level shifting from 3.3 V to 5 V?
No, the SN74CBTD3306DR does not support reverse-level shifting (3.3 V → 5 V). Its internal architecture uses diodes tied to VCC to clamp and translate 5-V inputs downward to approximately 3.3-V output levels. When driven from a 3.3-V source, the output remains near 3.3 V regardless of VCC = 5 V, and no boosting or up-translating circuitry is present. For bidirectional translation, SN74CBTD3306DR must be used strictly in the 5-V-to-3.3-V direction; alternative devices like SN74AVC4T245PW are required for full bidirectional capability.
What is the maximum continuous current rating per channel of the SN74CBTD3306DR?
The SN74CBTD3306DR supports a maximum continuous channel current of 128 mA per switch, as specified in its absolute maximum ratings. However, for reliable operation within recommended conditions, the datasheet specifies on-resistance testing at 30 mA (with ron = 5–7 Ω) and 64 mA (VIK = −1.2 V). Sustained operation above 30 mA increases self-heating and may degrade timing performance or long-term reliability - design margins should maintain ≤30 mA per channel under normal operation, especially in SOIC packages with θJA = 97°C/W.
How does the OE (output-enable) input behave in the SN74CBTD3306DR?
The OE inputs (1OE and 2OE) on the SN74CBTD3306DR are active-low control signals: when pulled low, the corresponding A↔B switch conducts with low on-resistance; when pulled high, the switch enters high-impedance state, disconnecting the ports. Each OE controls its respective channel independently - there is no shared enable or synchronization requirement. Inputs are TTL-compatible (VIL ≤ 0.8 V, VIH ≥ 2 V), and unused OE pins must be tied to either VCC or GND to prevent floating states that could cause erratic switching or increased ICC.
Is the SN74CBTD3306DR pin-compatible with other members of the 74CBT family?
The SN74CBTD3306DR shares the same SOIC-8 pinout (D package) and functional pin mapping with other dual-bus-switch variants in TI's 74CBT series, including SN74CBT3244D and SN74CBT3257D. However, electrical behavior differs significantly: SN74CBTD3306DR integrates level-shifting diodes and has distinct VIH/VIL thresholds, while SN74CBT3244D is a non-translating octal switch. Direct substitution is not recommended without verifying control logic compatibility, voltage translation requirements, and on-resistance specifications - SN74CBTD3306DR is not a drop-in replacement for non-level-shifting variants.
SN74CBTD3306DR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CBTD
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Bus Switch
- Circuit:
- 1 x 1:1
- Independent Circuits:
- 2
- 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:
- 8-SOIC
SN74CBTD3306DR FAQ
1.How can I place an order for SN74CBTD3306DR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CBTD3306DR 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 SN74CBTD3306DR reliable?
The price and inventory of SN74CBTD3306DR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBTD3306DR is usually 5 days.
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SN74CBTD3306DR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CBTD3306DR 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 SN74CBTD3306DR?
For technical support, including SN74CBTD3306DR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBTD3306DR requirements.
6.How does Aetrix verify that SN74CBTD3306DR is sourced from the original manufacturer or authorized distributors?
All SN74CBTD3306DR 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 SN74CBTD3306DR meets industry standards.
7.What is the process for return or replacement of SN74CBTD3306DR?
All SN74CBTD3306DR units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBTD3306DR, 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 SN74CBTD3306DR part is unused and in its original packaging.
Return procedure for SN74CBTD3306DR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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