Texas Instruments SN74CBT3245CDGVR

Overview

SN74CBT3245CDGVR from Texas Instruments is an 8-bit high-speed TTL-compatible FET bus switch with bidirectional data flow, near-zero propagation delay (0.15 ns typical at 5 V), 3 Ω typical ON-state resistance, 5.5 pF typical OFF-state I/O capacitance, and undershoot protection up to −2 V on A/B ports - used for USB interface isolation and memory interleaving in industrial control backplanes.

For engineers reviewing the SN74CBT3245CDGVR datasheet, SN74CBT3245CDGVR pinout, SN74CBT3245CDGVR application, or SN74CBT3245CDGVR equivalent, key selection criteria include VCC operating range (4–5.5 V), Ioff partial-power-down support, 0–5-V signal level compatibility across 8 data channels, and TVSOP-20 package thermal performance (θJA = 92°C/W).

Technical Context

This device implements eight independent FET-based analog/digital switches controlled by a single active-low OE input; when OE is low, A and B ports are connected with minimal ron and tpd; when OE is high, ports enter high-impedance state with Ioff limiting backflow during partial power-down.

The integrated undershoot-protection circuitry actively monitors A/B port voltages and forces switch disable if undershoot below −2 V occurs, preventing false turn-on and latch-up; all I/Os support 0–5.5 V signaling regardless of VCC, enabling mixed-voltage domain bridging without level shifters.

Key Specifications

Pinout & Package

SN74CBT3245CDGVR is housed in a 20-pin TVSOP (DGV) package, 4.3 mm × 6.2 mm footprint, 1.2 mm max height, with exposed thermal pad (non-electrical), JEDEC MO-153 compliant, and optimized for high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT3245CDGVR, SN74CBTD3384CDW trades speed and undershoot immunity for enhanced VCC rail isolation, while SN74LVC2G66DCKR offers compact size at the expense of channel count and transient protection - making SN74CBT3245CDGVR optimal for 8-bit, high-reliability, mixed-voltage bus gating.

Availability

SN74CBT3245CDGVR is available at Aetrix Electronics and suitable for USB interface isolation, memory interleaving, and industrial bus isolation requiring stable component supply, full production traceability, and long-term lifecycle support.

Supply support for SN74CBT3245CDGVR 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 decades of expertise in high-reliability interface ICs.

The SN74CBT3245C family was designed specifically for high-speed, low-distortion bus switching in mixed-voltage industrial and communications systems - emphasizing robustness, signal fidelity, and seamless integration across logic families.

FAQ

What is the maximum undershoot voltage the SN74CBT3245CDGVR can withstand on its A and B ports?

The SN74CBT3245CDGVR provides active undershoot protection up to −2 V on both A and B ports, as verified in the absolute maximum ratings and undershoot characteristics section of the SCDS131A datasheet. This protection is implemented via internal sensing circuitry that forces the switch into the OFF state during undershoot events, preventing unintended conduction. The SN74CBT3245CDGVR remains functional and undamaged within this limit.

Does the SN74CBT3245CDGVR support partial-power-down operation, and how is it implemented?

Yes, the SN74CBT3245CDGVR supports partial-power-down operation via its Ioff feature, which limits current backflow to ≤10 µA when VCC = 0 V. This is achieved through internal circuitry that isolates the I/O paths during power-off conditions, ensuring safe operation during hot-swap or multi-rail sequencing. The SN74CBT3245CDGVR maintains high-impedance isolation even when unpowered, protecting downstream circuitry.

What is the typical ON-state resistance (ron) of the SN74CBT3245CDGVR, and how does it affect signal integrity?

The SN74CBT3245CDGVR has a typical ON-state resistance of 3 Ω at VCC = 4.5 V and IO = 30 mA, as specified in the electrical characteristics table. This low ron minimizes voltage drop (<100 mV at 33 mA) and insertion loss, preserving signal amplitude and edge rate in high-speed digital and analog paths. The SN74CBT3245CDGVR's ron consistency across temperature and voltage ensures predictable timing behavior in precision applications.

Can the SN74CBT3245CDGVR interface between 1.8-V and 5-V logic domains without external level shifters?

Yes, the SN74CBT3245CDGVR supports 0–5.5 V signaling on all A and B I/O pins independent of VCC, enabling direct interfacing between 1.8-V, 2.5-V, 3.3-V, and 5-V logic domains. Its VI/O rating exceeds standard logic thresholds, and its bidirectional architecture eliminates direction-control complexity. The SN74CBT3245CDGVR achieves this without external components, reducing BOM count and layout area.

What package type is used for the SN74CBT3245CDGVR, and what are its key mechanical features?

The SN74CBT3245CDGVR uses a 20-pin TVSOP (DGV) package measuring 4.3 mm × 6.2 mm with 0.5-mm pitch, 1.2-mm max height, and JEDEC MO-153 compliance. It includes an exposed thermal pad for improved heat dissipation (θJA = 92°C/W), fine-pitch gull-wing leads for reliable reflow soldering, and a pin-1 index area for automated placement. The SN74CBT3245CDGVR's compact footprint supports high-density routing in space-constrained industrial PCBs.