Texas Instruments SN74CBTD3306D

Overview

SN74CBTD3306D from Texas Instruments is a dual FET bus switch with integrated level-shifting capability, designed for bidirectional 5-V-to-3.3-V signal translation in mixed-voltage systems. It features two independent switches with 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. It is used in memory address/data bus isolation and voltage-domain bridging in industrial microcontroller interfaces.

For engineers reviewing the SN74CBTD3306D datasheet, SN74CBTD3306D pinout, SN74CBTD3306D application, or SN74CBTD3306D equivalent, this device is selected for low-latency, bidirectional bus switching where supply-rail translation and sub-1-ns propagation delay are critical in legacy 5-V/3.3-V coexistence designs.

Technical Context

The SN74CBTD3306D implements two independent NMOS transmission-gate switches, each controlled by a dedicated OE input operating at TTL logic thresholds (VIL ≤ 0.8 V, VIH ≥ 2 V). Its internal clamp diode to VCC enables passive level shifting without external components when A-side signals are 5 V and B-side loads operate at 3.3 V.

Switching behavior follows positive-logic enable: OE low connects A↔B ports; OE high disconnects both ports with <4 pF off-capacitance. Propagation delay is specified at 0.25 ns (typ) under CL = 50 pF, reflecting its optimized RC time constant using typical 5-Ω ron and low parasitic capacitance.

Key Specifications

Pinout & Package

SN74CBTD3306D is housed in an 8-pin SOIC (D) package with 1.27 mm pitch, 3.91 mm width, and 4.9 mm length per TI D0008A outline. Thermal resistance θJA is 97°C/W, supporting operation up to 85°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBTD3306D, SN74CBT3306D lacks on-chip level shifting and demands external components for mixed-voltage use, while SN74LVC1T45DBVR offers flexible dual-supply operation but supports only one signal line and cannot replace dual-bus isolation in parallel architectures.

Availability

SN74CBTD3306D is available at Aetrix Electronics and suitable for memory bus isolation, microcontroller I/O bridging, and FPGA configuration interfaces requiring stable component supply and long-term industrial lifecycle support.

Supply support for SN74CBTD3306D 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 for industrial, automotive, and communications markets.

The SN74CBTD3306D belongs to TI's 74CBT family of advanced bus switches, engineered specifically for low-latency, level-shifting interconnection in mixed-voltage digital systems.

FAQ

What is the maximum operating temperature range for the SN74CBTD3306D?

The SN74CBTD3306D is rated for operation from −40°C to +85°C ambient temperature, matching industrial-grade requirements. This range is confirmed in the "recommended operating conditions" table of the official datasheet (SCDS030L), and applies to both SOIC (D) and TSSOP (PW) package variants of the SN74CBTD3306D.

Does the SN74CBTD3306D require external pull-up resistors on its OE inputs?

No, the SN74CBTD3306D does not require external pull-up resistors on its OE inputs because it features TTL-compatible input thresholds (VIL ≤ 0.8 V, VIH ≥ 2 V) and internal input structure that ensures defined logic states when driven directly from 5-V CMOS or TTL sources. The SN74CBTD3306D datasheet explicitly states that unused control inputs must be held at VCC or GND-but not via weak pull-ups-to guarantee proper operation.

Can the SN74CBTD3306D translate signals from 3.3 V to 5 V?

No, the SN74CBTD3306D is designed specifically for 5-V-to-3.3-V level shifting via its integrated VCC-referenced diode clamp; it does not support reverse translation (3.3-V-to-5-V). When 3.3-V signals are applied to the A port, the internal diode remains reverse-biased and provides no clamping action, so B-port output remains at ~3.3 V without boosting. This unidirectional capability is documented in the functional description and absolute maximum ratings of the SN74CBTD3306D datasheet.

What is the typical on-state resistance of the SN74CBTD3306D and how does it affect signal integrity?

The SN74CBTD3306D has a typical on-state resistance (ron) of 5 Ω, measured at VCC = 4.5 V with VI = 0 V and II = 30 mA. This low ron minimizes voltage drop across the switch (e.g., <150 mV at 30 mA), preserving logic-high margins and reducing rise-time degradation in high-speed parallel buses-critical for maintaining setup/hold timing in SRAM or Flash interfaces using the SN74CBTD3306D.

Is the SN74CBTD3306D pin-compatible with other devices in the 74CBT family?

Yes, the SN74CBTD3306D shares identical 8-pin SOIC (D) pinout and functional mapping with SN74CBT3306D and SN74CB3Q3306D, including matching 1OE/1A/1B/GND/2OE/2A/2B/VCC assignments. However, differences in internal level-shifting architecture mean that substituting SN74CBTD3306D for SN74CBT3306D introduces automatic 5-V-to-3.3-V translation-so electrical behavior changes even though physical layout remains unchanged.