Texas Instruments SN74CBT3383CPW

Overview

SN74CBT3383CPW from Texas Instruments is a 10-bit TTL-compatible FET bus-exchange switch with bidirectional data flow, 3 Ω typical ON-state resistance (ron), −2 V undershoot protection on A/B ports, and near-zero propagation delay (0.15 ns at 5 V). It operates from 4 V to 5.5 V and supports 0–5 V signaling levels across mixed-voltage systems such as PCI interfaces and memory interleaving.

For engineers reviewing the SN74CBT3383CPW datasheet, SN74CBT3383CPW pinout, SN74CBT3383CPW application, or SN74CBT3383CPW equivalent, key selection criteria include its Ioff partial-power-down capability, 8 pF OFF-state I/O capacitance, BE/BX dual-control logic for port exchange, and TSSOP-24 package compatibility with high-density PCB layouts.

Technical Context

The SN74CBT3383CPW implements a 5-bit dual-path bus-exchange architecture controlled by BE (bus-enable) and BX (bus-exchange) inputs: when BE = L, A1↔B1 and A2↔B2 paths are active; when BX = H, A1 connects to B2 and A2 to B1. Each path uses low-ron FET switches with integrated undershoot-protection circuitry that clamps transient excursions down to −2 V while maintaining OFF-state isolation.

It features Ioff protection enabling safe partial-power-down operation-preventing backflow current when VCC = 0-and supports TTL/5-V/3.3-V CMOS control inputs. Its 0–5.5 V data I/O voltage range, ±128 mA ON-state current rating, and JESD 78 Class II latch-up immunity make it suitable for robust signal gating in industrial and computing infrastructure.

Key Specifications

Pinout & Package

TSSOP-24 package (PW), 0.65 mm pitch, body size 7.8 mm × 4.4 mm, thermal resistance θJA = 88°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT3383CPW, SN74CBTD3383CPW adds 3.3-V control compatibility and stronger ESD protection but shares identical exchange logic and TSSOP-24 footprint; PI3CH403QEX offers higher voltage tolerance but lacks BX-controlled port reversal and requires PCB redesign due to non-pin-compatible pin assignment.

Availability

SN74CBT3383CPW is available at Aetrix Electronics and suitable for PCI interface design, memory subsystem development, and bus isolation applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for SN74CBT3383CPW 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 U.S.-based semiconductor company specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The SN74CBT3383CPW belongs to TI's CBT (CrossBar Technology) logic family, engineered for high-speed, low-distortion signal routing in computing and data infrastructure where nanosecond timing and voltage-level flexibility are critical.

FAQ

What is the maximum undershoot voltage the SN74CBT3383CPW can withstand on its A and B ports?

The SN74CBT3383CPW provides active undershoot protection up to −2 V on both A and B ports, verified per datasheet SCDS175. This is achieved through integrated clamping circuitry that senses negative transients and forces the switch into a reliable OFF state, preventing unintended conduction or latch-up during ESD events or signal reflections. The SN74CBT3383CPW maintains this specification across its full operating temperature range of −40°C to 85°C.

Does the SN74CBT3383CPW support partial-power-down operation, and how is it implemented?

Yes, the SN74CBT3383CPW supports partial-power-down operation via its Ioff feature. When VCC = 0 V, the device limits OFF-state current to 10 µA maximum, blocking damaging backflow current from live I/O lines into the unpowered device. This behavior is guaranteed over the full VI/O range (0 to 5.5 V) and enables safe hot-swap and power-gating scenarios without external isolation components. The SN74CBT3383CPW achieves this through internal transistor biasing that disables conduction paths while preserving terminal isolation.

What are the logic states and functions of the BE and BX inputs on the SN74CBT3383CPW?

The BE (Bus Enable) input is active-low: when BE = L, the 10-bit switch is enabled; when BE = H, all paths enter high-impedance isolation. The BX (Bus eXchange) input selects mapping direction only when BE = L: BX = L configures straight-through connection (A1↔B1, A2↔B2), while BX = H swaps ports (A1↔B2, A2↔B1). Both inputs accept TTL- or CMOS-level signals (0–5.5 V), and unused inputs must be tied to VCC or GND per TI application note SCBA004. These control functions are intrinsic to the SN74CBT3383CPW's architecture and do not require external decoding logic.

Can the SN74CBT3383CPW interface between 1.8-V and 5-V logic domains without level shifters?

Yes, the SN74CBT3383CPW supports 0–5.5 V signaling on all data I/O pins (A and B ports), allowing direct connection between 1.8-V, 2.5-V, 3.3-V, and 5-V logic families. Its voltage-tolerant FET structure ensures proper switching regardless of voltage differential across the switch, and its control inputs (BE, BX) accept TTL/5-V/3.3-V CMOS levels. No external level shifters are needed - the SN74CBT3383CPW inherently handles mixed-voltage interconnect in applications like FPGA-to-peripheral bridging or legacy bus extension.

What is the typical ON-state resistance (ron) of the SN74CBT3383CPW, and how does it affect signal integrity?

The SN74CBT3383CPW has a typical ON-state resistance (ron) of 3 Ω at VCC = 4.5 V and IO = 30 mA, with a maximum of 6 Ω across operating conditions. This low ron minimizes voltage drop and power dissipation in high-speed data paths, preserving signal amplitude and edge rates. At 100 MHz, a 3 Ω ron contributes <0.1 dB insertion loss in 50-Ω systems and avoids measurable rise-time degradation - critical for maintaining eye diagram margins in PCI and memory bus applications. The SN74CBT3383CPW's ron consistency across voltage and temperature further ensures predictable performance in thermally varying environments.