Texas Instruments SN74CB3T3383DBQR

Overview

SN74CB3T3383DBQR from Texas Instruments is a 10-bit FET bus-exchange switch with bidirectional data flow, 5 Ω typical ON-state resistance, 8 pF typical OFF-state I/O capacitance, and VCC range of 2.3 V to 3.6 V. It enables voltage translation across mixed-mode logic domains (e.g., 5-V TTL to 3.3-V LVTTL) in memory interleaving and bus isolation applications.

For engineers reviewing the SN74CB3T3383DBQR datasheet, SN74CB3T3383DBQR pinout, SN74CB3T3383DBQR application, or SN74CB3T3383DBQR equivalent, key selection criteria include its 0.15 ns propagation delay at 2.5 V, Ioff partial-power-down support, 5-V-tolerant I/Os, and TSSOP-24 package compatibility with space-constrained portable systems.

Technical Context

The SN74CB3T3383DBQR implements a dual 5-bit bus-exchange architecture controlled by BE (bus-enable) and BX (bus-exchange select) inputs. When BE is low, data paths are dynamically reconfigurable: BX = L routes A1↔B1 and A2↔B2; BX = H swaps A1↔B2 and A2↔B1. This enables real-time signal routing without direction control logic.

Its FET-based switch design delivers near-zero propagation delay and tracks VCC for output voltage translation - VOH ≈ VCC when VIH ≥ VCC − 1 V. The device supports 0–5-V signaling levels (0.8 V, 1.2 V, 1.5 V, 1.8 V, 2.5 V, 3.3 V, 5 V) on all data I/Os while maintaining 5-V tolerance regardless of VCC state.

Key Specifications

Pinout & Package

SN74CB3T3383DBQR is housed in a 24-pin TSSOP (PW) package, 7.9 mm × 4.5 mm × 1.2 mm, with 0.65 mm pitch and exposed metal thermal pad per TI PW0024A outline.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT3383DBQR and TS3A24159DGSR, the SN74CB3T3383DBQR uniquely combines 10-bit bus exchange, Ioff-enabled power-down isolation, and VCC-tracked voltage translation - making it irreplaceable in memory subsystems requiring dynamic topology reconfiguration and robust low-power operation.

Availability

SN74CB3T3383DBQR is available at Aetrix Electronics and suitable for memory interleaving, bus isolation, level translation bridge, and portable system signal routing applications requiring stable component supply and long-term production continuity.

Supply support for SN74CB3T3383DBQR 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 for industrial, automotive, and communications markets.

The SN74CB3T3383DBQR belongs to TI's CB3T family of high-speed FET bus switches, designed specifically for low-latency, low-power voltage translation and dynamic bus topology management in mixed-signal systems.

FAQ

What is the maximum data rate supported by the SN74CB3T3383DBQR?

The SN74CB3T3383DBQR does not specify a maximum data rate in its datasheet, but its 0.15 ns minimum propagation delay at 2.5 V and 8 pF OFF-state capacitance support clean signal transmission up to 3+ Gbps in differential pairs or >500 MHz in single-ended buses. Actual achievable rate depends on PCB layout, termination, and load capacitance - verified via eye-diagram testing per JEDEC standards using the SN74CB3T3383DBQR in loopback configurations.

Does the SN74CB3T3383DBQR require external pull-up resistors on BE and BX inputs?

Yes - the SN74CB3T3383DBQR requires a pull-up resistor on the BE pin to VCC to ensure high-impedance state during power-up or brownout; TI recommends ≥10 kΩ based on driver sink capability. BX has no such requirement and may be driven directly by CMOS or TTL logic. Failure to tie BE high during power sequencing risks unintended bus connection and signal contention, which the SN74CB3T3383DBQR cannot prevent autonomously.

Can the SN74CB3T3383DBQR translate 5-V inputs to 1.8-V outputs?

No - the SN74CB3T3383DBQR outputs track VCC, so 1.8-V output requires VCC = 1.8 V, which falls outside its specified 2.3–3.6 V operating range. It supports 5-V → 3.3-V (with VCC = 3.3 V) and 5-V/3.3-V → 2.5-V (with VCC = 2.5 V) translation only. For 1.8-V translation, use SN74AVC4T245 or similar AVC-family translators explicitly rated down to 1.65 V VCC, not the SN74CB3T3383DBQR.

How does the Ioff feature of the SN74CB3T3383DBQR protect downstream circuitry?

The Ioff feature of the SN74CB3T3383DBQR disables all internal FET channels and isolates Port A and Port B when VCC = 0 V, limiting I/O leakage to ≤10 µA even with 5.5 V applied to any pin. This prevents damaging backflow current into a powered-down section of the system - for example, protecting a dormant FPGA I/O bank from voltage injection through shared buses. The SN74CB3T3383DBQR achieves this without external power sequencing controllers.

Is the SN74CB3T3383DBQR pin-compatible with other packages in the same family?

Yes - the SN74CB3T3383DBQR (TSSOP-24) shares identical pinout and electrical behavior with SN74CB3T3383DWR (SOIC-24) and SN74CB3T3383DGVR (TVSOP-24), including identical BE/BX control mapping and A/B port assignments. Mechanical differences (package size, thermal pad, pitch) require separate PCB footprints, but logic design, firmware control, and schematic symbols remain fully interchangeable across these variants of the SN74CB3T3383DBQR family.