Texas Instruments SN74CBT3245CDWR

Overview

SN74CBT3245CDWR from Texas Instruments is an 8-bit bidirectional FET bus switch IC with TTL-compatible control inputs, 3 Ω typical ON-state resistance, near-zero propagation delay (0.15 ns at 5 V), and undershoot protection up to −2 V on both A and B ports. It operates from 4 V to 5.5 V and supports mixed-voltage signaling (0.8 V to 5 V) in USB interface and memory interleaving applications.

For engineers reviewing the SN74CBT3245CDWR datasheet, SN74CBT3245CDWR pinout, SN74CBT3245CDWR application, or SN74CBT3245CDWR equivalent, key selection criteria include Ioff partial-power-down capability, 5.5 pF typical OFF-state I/O capacitance, OE-controlled bidirectional isolation, and SOIC-20 package compatibility with industrial bus gating designs.

Technical Context

This device implements eight independent FET transmission gates controlled by a single active-low OE input. When OE is low, A and B ports are connected with minimal ron-induced distortion; when OE is high, both ports enter high-impedance state with Ioff limiting backflow current during partial power-down.

The integrated undershoot-protection circuitry actively monitors port voltage and forces switch disable if either A or B port drops below −2 V, preventing false turn-on and latch-up. All data I/Os support 0–5-V signaling levels regardless of VCC, enabling level translation between 1.8-V, 2.5-V, 3.3-V, and 5-V domains without external biasing.

Key Specifications

Pinout & Package

SN74CBT3245CDWR uses a 20-pin SOIC (DW) package with 7.5 mm × 12.8 mm body, 1.27 mm lead pitch, and 2.65 mm maximum height per JEDEC MS-013. Pin 1 index located at top-left corner with notch marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT3245CDWR, SN74CBTD3384CDW offers finer channel granularity but sacrifices voltage range and undershoot resilience, while PI3CH400LE provides broader VCC flexibility at the expense of protection and lower ron - making SN74CBT3245CDWR optimal for 5-V industrial bus isolation requiring fail-safe operation.

Availability

SN74CBT3245CDWR is available at Aetrix Electronics and suitable for USB interface isolation, memory interleaving, and industrial backplane gating requiring stable component supply, long-term lifecycle support, and RoHS-compliant SOIC packaging.

Supply support for SN74CBT3245CDWR 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 with over 50 years of innovation in high-speed interface ICs.

The SN74CBT3245C family was designed specifically for low-distortion, bidirectional bus switching in mixed-voltage computing and industrial systems where signal integrity, power sequencing safety, and compact footprint are critical.

FAQ

What is the maximum undershoot voltage the SN74CBT3245CDWR can tolerate on its A and B ports?

The SN74CBT3245CDWR features active undershoot protection that ensures reliable OFF-state behavior down to −2 V on both A and B ports, as verified in the absolute maximum ratings and undershoot characteristics section of the datasheet. This eliminates risk of unintended conduction during transient negative excursions, making SN74CBT3245CDWR suitable for electrically noisy environments such as industrial motor drives or automotive gate driver interfaces.

Does the SN74CBT3245CDWR support level translation between different logic families?

Yes, the SN74CBT3245CDWR supports true bidirectional level translation across 0.8-V, 1.2-V, 1.5-V, 1.8-V, 2.5-V, 3.3-V, and 5-V domains without external components. Its data I/Os operate independently of VCC voltage, allowing SN74CBT3245CDWR to pass signals between mismatched voltage rails while maintaining signal fidelity and timing integrity.

How does the Ioff feature of the SN74CBT3245CDWR improve system reliability during partial power-down?

The Ioff feature limits current backflow to ≤10 µA when VCC = 0 V, preventing damage to powered-down sections of a system and avoiding bus contention. In configurations where SN74CBT3245CDWR connects subsystems with independent power domains, this ensures safe isolation during firmware updates, sleep mode entry, or modular hot-swap - a key requirement validated per JESD 78 Class II latch-up testing.

What is the recommended OE pin handling strategy during power-up for the SN74CBT3245CDWR?

TI recommends tying OE to VCC through a pull-up resistor to ensure high-impedance isolation at power-on. The minimum resistor value depends on the driver's sink capability, but typical values range from 4.7 kΩ to 10 kΩ. This guarantees that SN74CBT3245CDWR remains disabled until firmware explicitly asserts OE low, preventing spurious data coupling during boot sequences.

Is the SN74CBT3245CDWR pin-compatible with other members of the SN74CBT3245C family?

Yes, all variants of the SN74CBT3245C - including SN74CBT3245CDWR (SOIC), SN74CBT3245CDBR (SSOP), and SN74CBT3245CPWR (TSSOP) - share identical 20-pin functional pinouts and electrical specifications. Mechanical differences exist only in package dimensions and thermal performance; SN74CBT3245CDWR's SOIC-20 footprint is fully interchangeable at the schematic level with no netlist or layout changes required.