Texas Instruments SN74CBT3244CDBQR

Overview

SN74CBT3244CDBQR from Texas Instruments is a high-speed TTL-compatible 8-bit FET bus switch organized as two independent 4-bit switches, featuring near-zero propagation delay (0.15 ns typical at 5 V), low ON-state resistance (3 Ω typical), and bidirectional signal flow. It supports 0–5-V signaling across mixed-voltage systems and enables bus isolation in memory and USB interfaces.

For engineers reviewing the SN74CBT3244CDBQR datasheet, SN74CBT3244CDBQR pinout, SN74CBT3244CDBQR application, or SN74CBT3244CDBQR equivalent, key selection criteria include undershoot protection to −2 V, Ioff partial-power-down support, 5.5-pF OFF-state I/O capacitance, and SSOP-20 (DBQ) package compatibility with industrial temperature range (−40°C to 85°C).

Technical Context

The SN74CBT3244CDBQR implements dual 4-bit FET-based analog/digital switches with separate active-low output-enable inputs (1OE, 2OE). Each switch channel provides true bidirectional conduction with no direction control required, and internal undershoot-protection circuitry actively clamps A/B port transients down to −2 V while maintaining OFF-state integrity.

It features Ioff functionality that blocks current backflow during partial power-down, supports TTL- and CMOS-level control inputs (VIH = 2 V min, VIL = 0.8 V max), and operates across 4 V–5.5 V VCC with 3 µA max ICC. The device meets JESD 78 Class II latch-up (>100 mA) and JESD 22 ESD standards (2000-V HBM, 1000-V CDM).

Key Specifications

Pinout & Package

SN74CBT3244CDBQR is housed in a 20-pin SSOP (Shrink Small-Outline Package) with DBQ designation, 0.65 mm lead pitch, body dimensions 7.2 mm × 5.3 mm × 1.95 mm max height, and moisture sensitivity level (MSL) 2–260°C–1 year.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT3244CDBQR, SN74CBTD3384CDBQR offers discrete bit control but sacrifices bidirectionality and voltage flexibility, while 74LVC2G66GW,115 provides wider temp range and smaller footprint but cannot replace dual 4-bit isolation in bus architectures.

Availability

SN74CBT3244CDBQR is available at Aetrix Electronics and suitable for USB interface design, memory interleaving systems, and industrial bus isolation requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for SN74CBT3244CDBQR 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 focused on analog, embedded processing, and connectivity technologies, with over 90 years of innovation in high-reliability IC design.

The SN74CBT3244CDBQR belongs to TI's CBT (Crossbar Bus Transceiver) family, engineered specifically for low-distortion, high-speed digital and analog signal routing in mixed-voltage computing and peripheral interfaces.

FAQ

What is the maximum undershoot voltage the SN74CBT3244CDBQR can withstand on its A/B ports?

The SN74CBT3244CDBQR provides active undershoot protection down to −2 V on both A and B ports, verified per datasheet test conditions (VCC = 5.5 V, switch OFF). This ensures the device remains safely in the OFF state during negative transients, preventing unintended conduction or latch-up in hot-plug or noisy environments. The protection is implemented via integrated clamp circuitry, not external diodes.

Does the SN74CBT3244CDBQR support true bidirectional signal flow without direction control?

Yes, the SN74CBT3244CDBQR supports fully bidirectional signal flow between A and B ports with no direction pin or control required. When enabled (OE low), current flows equally well from A→B or B→A due to its symmetric FET switch architecture. This eliminates timing skew and control logic overhead-making it ideal for USB differential pairs, memory data buses, and analog signal gating where signal polarity is undefined.

What is the recommended power-up sequence for the SN74CBT3244CDBQR?

TI specifies that OE inputs should be tied to VCC via a pull-up resistor during power-up to ensure the switch starts in high-impedance (OFF) state. For SN74CBT3244CDBQR, this prevents unintended bus contention. The minimum pull-up value depends on driver sink capability, but 10 kΩ is commonly used. VCC must be applied before any I/O signals exceed −0.5 V or 5.5 V to avoid absolute maximum rating violations.

Can the SN74CBT3244CDBQR be used in analog signal paths such as audio or sensor interfaces?

Yes, the SN74CBT3244CDBQR is explicitly qualified for analog applications per its datasheet. With 3 Ω typical ron, 5.5 pF OFF-state capacitance, and flat frequency response up to 1 GHz, it delivers low THD and minimal insertion loss. Its 0–5-V I/O tolerance and bidirectional behavior make it suitable for routing line-level audio, thermistor bridges, or ADC/DAC reference paths-provided signal swing stays within VI/O limits (−0.5 V to 7 V).

Is the SN74CBT3244CDBQR pin-compatible with other packages in the same family?

No-SN74CBT3244CDBQR uses the SSOP-20 (DBQ) package with 0.65 mm pitch, which is mechanically distinct from SOIC (DW), TSSOP (PW), TVSOP (DGV), and VQFN (RGY) variants. While all share identical pin functions and logic, the DBQ package has different pad layout, thermal pad absence, and solder profile requirements. PCB redesign is required when substituting across packages-even though electrical behavior is identical.