Texas Instruments SN74CBT16390DLR

Overview

SN74CBT16390DLR from Texas Instruments is a 16-bit to 32-bit FET bus switch used for multiplexing/demultiplexing data paths between one A-port and two independent B-ports (1B and 2B). It features 5-Ω on-state resistance, TTL-compatible inputs, and dual output enables (OE1/OE2) enabling simultaneous or selective connection of the A-port to either or both B-ports - deployed in PCI bus slot isolation and memory interleaving applications.

For engineers reviewing the SN74CBT16390DLR datasheet, SN74CBT16390DLR pinout, SN74CBT16390DLR application, or SN74CBT16390DLR equivalent, key selection criteria include its 56-pin SSOP (DL) package, ±128 mA continuous channel current rating, sub-6 ns enable/disable timing, 0.25 ns propagation delay, and operation across –40°C to 85°C industrial temperature range.

Technical Context

This device implements a dual-channel 16-bit FET-based analog switch architecture with independent OE1 and OE2 control lines determining signal routing: OE1 low connects A to 1B; OE2 low connects A to 2B; both low enables A-to-both-B-path conduction. No internal logic decoding or level translation is performed - it operates as a passive bidirectional switch with rail-to-rail analog signal pass-through capability.

Each of the 32 switch channels exhibits matched on-resistance (5–7 Ω at VCC = 4.5 V), low off-capacitance (5.5 pF), and high off-isolation (>50 dB typical at 10 MHz), supporting high-speed digital bus switching without signal degradation. The device requires no power-up sequencing and draws only 3 µA ICC in static operation.

Key Specifications

Pinout & Package

SN74CBT16390DLR is housed in a 56-pin SSOP (Shrink Small-Outline Package) with 0.635 mm lead pitch and 11.4 mm × 14.24 mm body dimensions. The package is RoHS-compliant, moisture-sensitive level 1 (unlimited reflow), and designed for surface-mount assembly using standard stencil and reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT16390DLR, SN74CBTD16212DLR adds voltage translation but increases on-resistance and complexity, while SN74CBT3245ADLR reduces integration and routing flexibility but lowers BOM cost and layout area.

Availability

SN74CBT16390DLR is available at Aetrix Electronics and suitable for PCI slot management, memory interleaving, and industrial backplane multiplexing requiring stable component supply, long-lifecycle support, and guaranteed industrial-temperature performance.

Supply support for SN74CBT16390DLR 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 technologies, with over 90 years of innovation in high-reliability silicon design.

The SN74CBT16390DLR belongs to TI's Widebus™ family of high-speed FET bus switches, engineered specifically for low-latency, low-distortion digital signal routing in computing, communications, and industrial control infrastructure.

FAQ

What is the maximum continuous current rating per channel for SN74CBT16390DLR?

The SN74CBT16390DLR supports up to 128 mA continuous channel current per switch path, verified per absolute maximum ratings in the official datasheet. This rating applies across the full operating temperature range (–40°C to +85°C) and ensures reliable conduction without thermal derating in typical 5 V bus applications. Exceeding this value risks permanent damage or accelerated wear-out.

Does SN74CBT16390DLR support bidirectional signal flow?

Yes, SN74CBT16390DLR is fully bidirectional: signals pass equally well from A to 1B/2B or from 1B/2B to A, with identical on-resistance and timing characteristics in both directions. This behavior stems from its FET-based analog switch architecture - no directionality or internal logic imposes asymmetry, making it ideal for shared-bus architectures like PCI or memory data lines.

Can SN74CBT16390DLR operate with a 3.3 V supply?

No, SN74CBT16390DLR is specified only for 4.5 V to 5.5 V VCC operation. Its TTL-compatible input thresholds (VIH = 2 V, VIL = 0.8 V) and 5 Ω on-resistance are optimized for 5 V systems. Applying 3.3 V violates recommended operating conditions and may result in undefined switching behavior, increased Ron, or failure to meet timing specs - use SN74CBTD16212DLR instead for 3.3 V/5 V translation.

What is the function of the NC pins on SN74CBT16390DLR?

SN74CBT16390DLR has four NC (no internal connection) pins: 27, 28, 55, and 56. These pins are physically present but unconnected to any internal circuitry and must remain floating - no external pull-up, pull-down, or routing is permitted. Leaving them unconnected avoids parasitic coupling and ensures compliance with TI's validated thermal and electrical models for the DL package.

How does SN74CBT16390DLR handle simultaneous assertion of OE1 and OE2?

When both OE1 and OE2 are low, SN74CBT16390DLR electrically connects the A-port to both 1B and 2B ports simultaneously - effectively creating a 1:2 fanout. This mode is explicitly defined in the function table and supports applications like broadcast writes or mirrored memory access. Signal integrity remains preserved due to matched Ron and low inter-channel crosstalk (< –50 dB).