Texas Instruments SN74CBT3306CDR

Overview

SN74CBT3306CDR from Texas Instruments is a dual 1-bit high-speed FET bus switch IC with bidirectional signal routing, 3 Ω typical ON-state resistance (ron), <0.24 ns propagation delay at 4 V, and −2 V undershoot protection on both A/B ports. It operates from 4 V to 5.5 V and supports mixed-voltage I/O (0.8 V to 5 V) in USB interface and bus isolation applications.

For engineers reviewing the SN74CBT3306CDR datasheet, SN74CBT3306CDR pinout, SN74CBT3306CDR application, or SN74CBT3306CDR equivalent, key selection criteria include its Ioff partial-power-down capability, 5 pF OFF-state I/O capacitance, TTL/CMOS-compatible control inputs, and SOIC-8 package compatibility with industrial temperature range (−40°C to 85°C).

Technical Context

The SN74CBT3306CDR implements two independent FET-based transmission gates, each controlled by dedicated OE inputs (1OE, 2OE), enabling per-channel ON/OFF state control. Its active undershoot-protection circuitry clamps A/B port voltages down to −2 V while maintaining high-impedance isolation during OFF state.

It features Ioff current limiting (<10 µA at VCC = 0 V) for safe partial-power-down operation, and supports bidirectional data flow with near-zero propagation delay due to low ron and minimal parasitic capacitance (Cio(OFF) = 5 pF typical). Control inputs accept TTL or 3.3/5-V CMOS logic levels.

Key Specifications

Pinout & Package

SN74CBT3306CDR is housed in an 8-pin SOIC (D) package (5.3 mm × 6.2 mm, 1.75 mm max height), RoHS-compliant with NiPdAu lead finish and MSL Level-1 rating.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bus switch applications.

Compared with SN74CBT3306CDR, SN74CBTD3306CDR extends fault resilience without layout change, while 74LVC1G3157DP,125 trades channel count and protection for size reduction - making SN74CBT3306CDR optimal for dual-line, industrial-grade isolation where reliability and timing transparency are prioritized.

Availability

SN74CBT3306CDR is available at Aetrix Electronics and suitable for USB interface design, industrial bus isolation, and low-distortion analog signal gating requiring stable component supply across production lifecycles.

Supply support for SN74CBT3306CDR 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 components.

The SN74CBT3306CDR belongs to TI's CBT (Crossbar Bus Transceiver) family, engineered for high-speed, low-distortion signal routing in mixed-voltage digital and analog systems - particularly targeting USB, industrial I/O, and memory expansion applications.

FAQ

What is the maximum undershoot voltage the SN74CBT3306CDR can withstand on its A and B ports?

The SN74CBT3306CDR provides active undershoot protection up to −2 V on both A and B ports, as verified in the SCDS127A datasheet's undershoot characteristics table. This protection is implemented via internal clamping circuitry that maintains proper OFF-state isolation even during negative transients, eliminating the need for external diodes in USB or hot-plug interfaces. The SN74CBT3306CDR achieves this without compromising signal integrity during normal operation.

Does the SN74CBT3306CDR support partial-power-down operation, and how is it implemented?

Yes, the SN74CBT3306CDR supports partial-power-down operation via its Ioff feature, which limits current to ≤10 µA when VCC = 0 V. This prevents damaging back-current flow through the switch during power sequencing or sleep modes. The SN74CBT3306CDR maintains high-impedance isolation between A/B ports under these conditions, ensuring downstream circuits remain protected. This behavior is fully specified in the recommended operating conditions and electrical characteristics sections of the datasheet.

What is the typical ON-state resistance (ron) of the SN74CBT3306CDR, and how does it affect signal performance?

The SN74CBT3306CDR has a typical ON-state resistance (ron) of 3 Ω at VCC = 4.5 V and IO = 30 mA, as measured per the datasheet's ron test conditions. This low ron minimizes voltage drop and power dissipation during signal pass-through, preserving amplitude accuracy and reducing thermal stress. In practice, the SN74CBT3306CDR delivers <0.01 dB gain error for line-level analog signals and enables clean digital edges up to 100 MHz without added jitter or distortion.

Can the SN74CBT3306CDR interface between different logic voltage domains, such as 1.8-V and 5-V systems?

Yes, the SN74CBT3306CDR supports 0 to 5-V signaling on its A/B data I/Os independently of VCC, enabling seamless interfacing between 0.8-V, 1.2-V, 1.5-V, 1.8-V, 2.5-V, 3.3-V, and 5-V logic domains. Its control inputs (1OE, 2OE) accept TTL or 3.3/5-V CMOS levels, allowing direct drive from most microcontrollers. This makes the SN74CBT3306CDR ideal for mixed-voltage board designs without external level shifters - a capability confirmed in the "Data I/Os Support 0 to 5-V Signaling Levels" specification.

What package type and thermal characteristics apply to the SN74CBT3306CDR?

The SN74CBT3306CDR uses the SOIC-8 (D) package with dimensions 5.3 mm × 6.2 mm and maximum height 1.75 mm. Its thermal impedance is θJA = 97°C/W, as specified in the absolute maximum ratings table. The device is RoHS-compliant with NiPdAu lead finish and MSL Level-1 (unlimited floor life at ≤30°C/60% RH), making it suitable for standard reflow assembly. These mechanical and thermal properties are documented in TI's PACKAGE OPTION ADDENDUM and confirmed for the SN74CBT3306CDR ordering variant.