Texas Instruments SN74CBT16209ADL

Overview

SN74CBT16209ADL from Texas Instruments is an 18-bit high-speed TTL-compatible bus switch with 5-Ω on-state resistance, operating from 4 V to 5.5 V supply, supporting bidirectional signal routing between four 9-bit port pairs (A1–A9/B1–B9) via three select inputs (S0–S2), and used in PCIe Gen1/Gen2 hot-swap buffer and memory-mapped I/O expansion applications.

For engineers reviewing the SN74CBT16209ADL datasheet, SN74CBT16209ADL pinout, SN74CBT16209ADL application, or SN74CBT16209ADL equivalent, this device enables low-latency, rail-to-rail analog/digital signal switching in FPGA interconnects, CPU-to-peripheral bridging, and legacy bus isolation where propagation delay <0.35 ns and channel current up to 128 mA are critical.

Technical Context

The SN74CBT16209ADL implements a 9-bit bus exchanger architecture using dual 9-bit bidirectional switch arrays controlled by S0/S1/S2 logic, allowing eight distinct A↔B port mapping configurations including full disconnect and cross-swapped modes. Its TTL-compatible control inputs accept VIH ≥2 V and VIL ≤0.8 V at VCC = 4–5.5 V.

Each of the 18 independent switch channels features matched on-resistance (4–8 Ω typical at VCC = 4.5 V, II = 30 mA), low off-capacitance (7.5 pF), and sub-nanosecond propagation delay (0.25 ns typical at VCC = 5 V, CL = 50 pF), enabling clean signal integrity for 100 MHz+ parallel bus operation without added termination.

Key Specifications

Pinout & Package

SN74CBT16209ADL uses a 48-pin SSOP (DL) package with 0.5-mm pitch, 12.4 mm × 6.1 mm body size, and 1.2-mm max height per JEDEC MO-153. Pin 1 is located at top-left corner with notch marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT16210DL (static switch) and SN74CBTD16210DLR (OE-enabled variant), SN74CBT16209ADL uniquely delivers programmable 9-bit port exchange via three logic inputs-enabling dynamic topology changes in space-constrained systems without adding FPGA logic or external decode circuitry.

Availability

SN74CBT16209ADL is available at Aetrix Electronics and suitable for PCIe interposers, FPGA I/O expansion hubs, legacy bus isolation, memory-mapped I/O bridges, and hot-swap controller designs requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for SN74CBT16209ADL 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.

SN74CBT16209ADL belongs to TI's Widebus™ family of high-speed bus switches, designed specifically for low-latency, low-distortion signal routing in computing, communications, and industrial control backplanes.

FAQ

What is the maximum operating frequency supported by the SN74CBT16209ADL?

The SN74CBT16209ADL does not specify a maximum clock frequency, but its 0.25 ns typical propagation delay and 7.5 pF off-capacitance support clean signal transmission up to 1 GHz small-signal bandwidth. In practice, it reliably handles 100 MHz parallel bus toggling with margin, as confirmed by switching characteristics measured at CL = 50 pF and VCC = 5 V in the official SCDS006O datasheet. System-level timing must account for board trace effects and load capacitance beyond the 50 pF test condition.

Does the SN74CBT16209ADL support level shifting between different logic families?

No, the SN74CBT16209ADL is a passive analog switch with no internal level-shifting circuitry. It passes signals bi-directionally within the same VCC domain (4–5.5 V), preserving input voltage levels at the output. For interfacing 3.3-V and 5-V logic, external series resistors or dedicated level translators like SN74AVC4T245 are required. The device's TTL-compatible inputs accept 2 V high and 0.8 V low thresholds, but output swing remains rail-to-rail relative to its own VCC.

How many unique port configurations does the SN74CBT16209ADL support?

The SN74CBT16209ADL supports eight distinct port configurations via its three select inputs (S2, S1, S0), as defined in the FUNCTION TABLE of the SCDS006O datasheet. These include full disconnect (000), four single-port mappings (e.g., A1↔B1 only), and three dual-port exchange modes (e.g., A1↔B1 + A2↔B2). All configurations operate simultaneously across all nine A/B pairs - no per-channel selection is possible.

Can unused control inputs (S0–S2) be left floating on the SN74CBT16209ADL?

No, all unused control inputs on the SN74CBT16209ADL must be actively tied to either VCC or GND to ensure predictable operation. Floating S0–S2 pins may cause metastability, unintended switching states, or increased ICC current due to input stage ambiguity. TI's SCBA004 application report explicitly warns against floating CMOS inputs and recommends pull-up or pull-down resistors (typically 10 kΩ) for unconnected select lines.

What is the thermal performance of the SN74CBT16209ADL in its SSOP (DL) package?

The SN74CBT16209ADL in the SSOP (DL) package has a specified thermal impedance θJA of 63°C/W, meaning junction temperature rises 63°C above ambient per watt of power dissipated. With typical ICC <3 µA and on-state power negligible at low currents, self-heating is minimal - even at full 128 mA per channel, total power remains below 100 mW. This allows reliable operation in sealed enclosures up to +85°C ambient without heatsinking.