Texas Instruments SN74CBT3384CPW

Overview

SN74CBT3384CPW from Texas Instruments is a high-speed TTL-compatible 10-bit FET bus switch organized as two independent 5-bit bidirectional switches, featuring 3 Ω typical ON-state resistance (ron), near-zero propagation delay (0.15 ns at VCC = 5 V), and undershoot protection up to −2 V on both A and B ports - used for PCI interface isolation and memory interleaving in industrial control backplanes.

For engineers reviewing the SN74CBT3384CPW datasheet, SN74CBT3384CPW pinout, SN74CBT3384CPW application, or SN74CBT3384CPW equivalent, key selection criteria include Ioff partial-power-down support, 0–5-V signal-level compatibility across 1.2-V to 5-V logic families, and TSSOP-24 package thermal performance (θJA = 88°C/W) for dense PCB layouts.

Technical Context

The SN74CBT3384CPW implements dual 5-bit FET-based analog/digital bus switches with separate OE controls (1OE, 2OE), enabling independent enable/disable of each 5-bit segment. Its active undershoot-protection circuitry monitors port voltage and forces OFF-state retention during −2 V transients - critical for hot-swap and mixed-voltage system robustness.

Each switch channel operates bidirectionally with ron = 3 Ω (typ) at VCC = 4.5 V and IO = 30 mA, while maintaining low OFF-state capacitance (Cio(OFF) = 5 pF typ) and ultra-low ICC = 3 µA max - supporting low-noise signal gating without loading adjacent traces or degrading edge integrity.

Key Specifications

Pinout & Package

TSSOP-24 package (PW), 7.9 mm × 4.5 mm × 1.2 mm max height, JEDEC MO-153 compliant, with exposed pad not electrically connected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBTD3384CPW and SN74LVC1G3157DBVR, the SN74CBT3384CPW uniquely balances ultra-low ron (3 Ω), −2 V undershoot protection, and Ioff-enabled partial-power-down - making it the only option among the three qualified for hot-swappable PCI and memory interleaving systems requiring simultaneous robustness and speed.

Availability

SN74CBT3384CPW is available at Aetrix Electronics and suitable for PCI interface isolation, memory interleaving, and industrial backplane gating requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant TSSOP packaging.

Supply support for SN74CBT3384CPW 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 logic solutions, with over 50 years of innovation in high-reliability interface and signal-path components.

The SN74CBT3384CPW belongs to TI's CBT (Crossbar Bus Transceiver) logic family, designed specifically for high-speed, low-distortion digital signal routing in computing, communications, and industrial infrastructure equipment.

FAQ

What is the maximum undershoot voltage the SN74CBT3384CPW can tolerate on its A and B ports?

The SN74CBT3384CPW provides active undershoot protection up to −2 V on both A and B ports, as verified in the SCDS132A datasheet Section 6. This feature ensures the switch remains reliably in the OFF state during transient negative excursions, preventing unintended conduction or latch-up in hot-swap applications. The SN74CBT3384CPW achieves this through integrated sensing circuitry that detects undershoot events and disables the internal FETs.

Does the SN74CBT3384CPW support partial-power-down operation, and how is it implemented?

Yes, the SN74CBT3384CPW supports partial-power-down operation via its Ioff feature, which limits current to 10 µA maximum when VCC = 0 V. This design prevents damaging backflow current from live I/O lines into the unpowered device, enabling safe insertion or removal in powered systems. The SN74CBT3384CPW maintains high-impedance isolation between A and B ports under these conditions, as confirmed in the recommended operating conditions table.

What logic families can directly drive the control inputs (1OE, 2OE) of the SN74CBT3384CPW?

The control inputs of the SN74CBT3384CPW accept TTL and 5-V/3.3-V CMOS outputs, with VIH = 2 V min and VIL = 0.8 V max specified over the full temperature range. This allows direct interfacing with standard 74LS, 74HC, and modern microcontroller GPIOs without level translation. The SN74CBT3384CPW also specifies ±1 µA max input leakage (IIN), ensuring minimal loading on driving sources.

What is the typical ON-state resistance (ron) of the SN74CBT3384CPW, and under what conditions is it measured?

The SN74CBT3384CPW has a typical ON-state resistance (ron) of 3 Ω, measured at VCC = 4.5 V, VI = 0 V, and IO = 30 mA per channel, as documented in the electrical characteristics table. This value reflects the lowest resistance achievable across the A–B path when the switch is enabled, contributing to minimal voltage drop and signal attenuation in high-current digital bus applications. The SN74CBT3384CPW maintains ron ≤ 6 Ω across its full operating range.

Is the SN74CBT3384CPW pin-compatible with other members of the CBT3384 family in the same TSSOP-24 package?

Yes, the SN74CBT3384CPW shares identical pinout and footprint with all TSSOP-24 variants of the CBT3384 family, including SN74CBT3384CPWR and SN74CBTD3384CPW. The top-side marking "CU384C" and package drawing PW0024A confirm mechanical and electrical pin equivalence. However, functional differences - such as bus-hold presence in SN74CBTD3384CPW - require verification against schematic intent before substitution. The SN74CBT3384CPW remains the base variant without added features.