Texas Instruments SN74CBT3306CPWR

Overview

SN74CBT3306CPWR from Texas Instruments is a dual 1-bit 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 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 SN74CBT3306CPWR datasheet, SN74CBT3306CPWR pinout, SN74CBT3306CPWR application, or SN74CBT3306CPWR equivalent, key selection criteria include partial-power-down Ioff support, TSSOP-8 package compatibility, low 5 pF OFF-state capacitance, and TTL/CMOS-compatible control inputs.

Technical Context

The SN74CBT3306CPWR implements two independent FET-based analog switches, each controlled by dedicated OE inputs (1OE, 2OE). Its active undershoot-protection circuitry clamps A/B port voltages down to −2 V while maintaining high-impedance isolation during OFF state.

Each switch provides near-zero propagation delay via low-impedance conduction path and features Ioff functionality that blocks backflow current when VCC = 0 V, enabling safe partial-power-down operation in multi-rail systems.

Key Specifications

Pinout & Package

TSSOP-8 package (PW), 3.0 mm × 4.4 mm body, 0.65 mm pitch, 1.2 mm max height, moisture sensitivity level 1, lead finish NiPdAu/Sn.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT3306CPWR, SN74CBTD3306CPWR adds bus-hold but increases leakage and complexity, while NC7SZ384P5X sacrifices channel count, protection, and voltage range for footprint reduction-making SN74CBT3306CPWR optimal for robust dual-lane, mixed-voltage isolation.

Availability

SN74CBT3306CPWR is available at Aetrix Electronics and suitable for USB interface design, industrial bus isolation, and FPGA I/O translation requiring stable component supply and long-term production continuity.

Supply support for SN74CBT3306CPWR 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, precision, and power efficiency.

The SN74CBT3306CPWR belongs to TI's CBT (Crossbar Bus Transceiver) family, engineered for high-speed, low-distortion signal routing in mixed-voltage digital and analog systems.

FAQ

What is the maximum undershoot voltage the SN74CBT3306CPWR can withstand on its A and B ports?

The SN74CBT3306CPWR provides active undershoot protection up to −2 V on both A and B ports, verified per test conditions in the SCDS127A datasheet. This capability prevents damage or malfunction during hot-plug events such as USB cable insertion, where negative transients may occur before system stabilization. The protection circuit remains functional as long as VCC is within its operating range (4 V to 5.5 V).

Does the SN74CBT3306CPWR support partial-power-down operation, and how is it implemented?

Yes, the SN74CBT3306CPWR supports partial-power-down operation via its Ioff feature, which limits reverse current to 10 µA when VCC = 0 V. This allows the device to safely isolate powered and unpowered sections of a system-for example, disconnecting a live USB bus from a powered-down host controller. The Ioff specification is tested per JESD 78 Class II latch-up standards and requires no external components to function.

Can the SN74CBT3306CPWR interface between 1.8-V and 3.3-V logic domains without external level shifters?

Yes, the SN74CBT3306CPWR supports 0–5.5 V signaling on its A and B ports regardless of VCC voltage (4–5.5 V), enabling direct interfacing between 1.8-V and 3.3-V logic domains. Its bidirectional, voltage-agnostic architecture eliminates the need for discrete level translators in applications like FPGA-to-peripheral communication, provided signal swing stays within the 0–5.5 V VI/O rating and control inputs meet VIH/VIL thresholds.

What is the typical ON-state resistance (ron) of the SN74CBT3306CPWR, and how does it affect signal integrity?

The SN74CBT3306CPWR has a typical ON-state resistance (ron) of 3 Ω at VCC = 4.5 V and IO = 30 mA. This low ron minimizes voltage drop and power dissipation across the switch, preserving signal amplitude and reducing distortion-especially critical in high-speed digital buses and analog audio paths. Measured at the lower of the A/B terminal voltages, ron remains stable across process, voltage, and temperature variations per the datasheet's characterization.

Is the SN74CBT3306CPWR pin-compatible with other members of the SN74CBT3306x family, such as the SOIC-packaged SN74CBT3306CDR?

Yes, the SN74CBT3306CPWR is pin-compatible with all variants in the SN74CBT3306x family-including SN74CBT3306CDR-sharing identical TSSOP-8 and SOIC-8 pinouts, terminal assignments, and electrical behavior. Both packages implement the same dual 1-bit switch architecture with identical control logic, ron, tpd, and I/O voltage ratings. Layout reuse is possible when migrating between PW and D packages, though thermal and mechanical constraints differ.