Texas Instruments SN74CBT3244CPWR

Overview

SN74CBT3244CPWR from Texas Instruments is a high-speed TTL-compatible 8-bit FET bus switch organized as two independent 4-bit switches, featuring 3 Ω typical ON-state resistance, near-zero propagation delay (0.15 ns at 5 V), and bidirectional signal flow with undershoot protection up to −2 V on A/B ports. It supports 0–5-V signaling across mixed-voltage systems and enables bus isolation in USB interface and memory interleaving applications.

For engineers reviewing the SN74CBT3244CPWR datasheet, SN74CBT3244CPWR pinout, SN74CBT3244CPWR application, or SN74CBT3244CPWR equivalent, key selection considerations include Ioff partial-power-down capability, 5.5 pF typical OFF-state I/O capacitance, ±128 mA switch current rating, and TSSOP-20 package compatibility with high-density PCB layouts.

Technical Context

The SN74CBT3244CPWR implements dual 4-bit FET-based analog/digital bus switches with independent OE control (1OE, 2OE). Each switch channel uses low-threshold MOSFETs enabling rail-to-rail signal pass-through without level translation.

Undershoot-protection circuitry actively monitors A/B port voltages and forces the switch into high-impedance state when −2 V undershoot is detected. The device supports partial-power-down via Ioff, preventing backflow current when VCC = 0 while maintaining isolation between ports.

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 4.4 mm × 6.5 mm body, 0.65 mm pitch, 1.2 mm max height, gull-wing leads, JEDEC MO-153 compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT3244CPWR, SN74CBTD3384CPWR trades higher ON-resistance and narrower voltage range for finer control granularity, while PI3CH400LE offers smaller size but omits critical undershoot protection needed in interface applications.

Availability

SN74CBT3244CPWR is available at Aetrix Electronics and suitable for USB interface design, memory interleaving architectures, and industrial bus isolation applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for SN74CBT3244CPWR 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 solutions, with over 90 years of innovation in high-reliability IC design.

The SN74CBT3244CPWR belongs to TI's CBT (Crosspoint Bus Transceiver) family, engineered for high-speed digital signal routing in mixed-voltage systems where low distortion, fast switching, and robust transient protection are critical.

FAQ

What is the maximum undershoot voltage the SN74CBT3244CPWR can withstand on its A/B ports?

The SN74CBT3244CPWR provides active undershoot protection up to −2 V on both A and B ports, as verified in the SCDS130A datasheet Section 6. This protection prevents erroneous switching and latch-up during hot-plug events or signal transients, making SN74CBT3244CPWR suitable for USB and memory interface applications where such conditions occur.

Does the SN74CBT3244CPWR support partial-power-down operation?

Yes, the SN74CBT3244CPWR supports partial-power-down via its Ioff feature, which limits leakage to 10 µA when VCC = 0 V while maintaining high-impedance isolation between A and B ports. This behavior is specified in the Electrical Characteristics table (page 5) and enables safe operation in systems with staggered power sequencing, such as multi-rail embedded controllers using SN74CBT3244CPWR for bus domain separation.

What is the typical ON-state resistance of the SN74CBT3244CPWR and how does it affect signal integrity?

The SN74CBT3244CPWR 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 electrical characteristics table. This low ron minimizes voltage drop and insertion loss-ensuring <0.1 V drop at 33 mA-preserving logic margins and reducing timing skew in high-speed data paths where SN74CBT3244CPWR is deployed as a bus gate or isolator.

Can the SN74CBT3244CPWR interface between 1.8-V and 5-V logic domains?

Yes, the SN74CBT3244CPWR supports 0–5.5 V signaling on all I/O pins independent of VCC (4–5.5 V), enabling direct connection between 1.8-V, 2.5-V, 3.3-V, and 5-V logic families without level shifters. This capability is explicitly stated in the "Data I/Os Support 0 to 5-V Signaling Levels" feature list and confirmed in the recommended operating conditions table (VI/O = 0 to 5.5 V).

What package type and dimensions does the SN74CBT3244CPWR use?

The SN74CBT3244CPWR uses a TSSOP-20 (PW) package: 4.4 mm × 6.5 mm body size, 0.65 mm lead pitch, 1.2 mm maximum height, gull-wing leads, and JEDEC MO-153 registration. Mechanical drawings confirm pin 1 indexing and thermal pad absence-consistent with standard TSSOP construction and verified in TI's PW0020A package outline document.