Texas Instruments SN74CBT3244CRGYR

Overview

SN74CBT3244CRGYR from Texas Instruments is a high-speed TTL-compatible FET bus switch organized as two independent 4-bit bidirectional switches, featuring 3 Ω typical ON-state resistance, near-zero propagation delay (0.15 ns at 5 V), and undershoot protection up to −2 V on A/B ports. It operates from 4 V to 5.5 V and supports 0–5-V signaling across mixed-voltage systems such as USB interface and memory interleaving.

For engineers reviewing the SN74CBT3244CRGYR datasheet, SN74CBT3244CRGYR pinout, SN74CBT3244CRGYR application, or SN74CBT3244CRGYR equivalent, key selection criteria include Ioff partial-power-down capability, 5.5 pF typical OFF-state I/O capacitance, bidirectional signal gating with no level-shifting required, and QFN-20 (RGY) package thermal performance (θJA = 37°C/W).

Technical Context

The SN74CBT3244CRGYR implements dual 4-bit FET-based analog/digital bus switches with independent 1OE and 2OE control inputs. Each switch channel provides true bidirectional conduction when enabled, with internal undershoot-protection circuitry actively clamping A/B port voltages below −2 V to maintain OFF-state integrity during transient events.

It features Ioff isolation during partial power-down, ensuring no backflow current when VCC = 0 V, and supports TTL- and CMOS-compatible control inputs (VIH ≥ 2 V, VIL ≤ 0.8 V). The device maintains high-impedance isolation between ports when disabled, with IOZ leakage ≤ ±10 µA at 5.5 V.

Key Specifications

Pinout & Package

VQFN-20 package (RGY), 3.5 mm × 4.5 mm, 0.5 mm pitch, exposed thermal pad, 1 mm max height. Pin 1 index located at top-left corner with marking "CU244C".

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBTD3384CDWR and PI3CH400QE, the SN74CBT3244CRGYR uniquely balances ultra-low propagation delay (0.15 ns), integrated −2 V undershoot protection, and compact 3.5 × 4.5 mm QFN packaging-making it optimal for space-constrained, high-speed, mixed-voltage bus isolation where transient immunity is critical.

Availability

SN74CBT3244CRGYR is available at Aetrix Electronics and suitable for USB interface design, memory interleaving architectures, and industrial bus isolation requiring stable component supply and long-term production continuity.

Supply support for SN74CBT3244CRGYR 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 components.

The SN74CBT3244CRGYR belongs to TI's CBT (Crossbar Bus Transceiver) family, engineered for ultra-low-latency, bidirectional signal routing in mixed-voltage digital systems where timing integrity and transient resilience are essential.

FAQ

What is the maximum undershoot voltage the SN74CBT3244CRGYR can withstand on its A and B ports?

The SN74CBT3244CRGYR provides active undershoot protection up to −2 V on both A and B ports. This is achieved through internal sensing circuitry that forces the switch into a guaranteed OFF state during negative transients, preventing unintended conduction or latch-up. The specification is verified per test conditions in the datasheet (VCC = 5.5 V, switch OFF), and applies specifically to the SN74CBT3244CRGYR in its RGY package configuration.

Does the SN74CBT3244CRGYR support partial-power-down operation, and how does Ioff function?

Yes, the SN74CBT3244CRGYR fully supports partial-power-down via its Ioff feature. When VCC = 0 V, Ioff limits reverse current to ≤10 µA even with 0–5.5 V applied to I/O pins, preventing damaging backflow into powered-down sections. This behavior is intrinsic to the FET architecture and is specified across temperature (−40°C to 85°C); it applies identically to all channels of the SN74CBT3244CRGYR.

What is the thermal performance of the SN74CBT3244CRGYR in its RGY package, and how should the exposed pad be handled?

The SN74CBT3244CRGYR in the VQFN-20 RGY package has a θJA of 37°C/W (measured per JESD 51-5). To achieve this rating, the exposed thermal pad must be soldered to a minimum 100 mm² PCB copper area with ≥4 thermal vias (0.3 mm diameter, filled/plugged). Failure to connect the pad degrades thermal performance by >40% and risks parametric drift under sustained 100-mA load conditions.

Can the SN74CBT3244CRGYR be used for analog signal switching, and what parameters validate that capability?

Yes, the SN74CBT3244CRGYR is qualified for analog signal switching. Its 3 Ω typical ron, 5.5 pF Cio(OFF), and flat frequency response up to 500 MHz (per application note SCBA004) support low-distortion analog multiplexing. Key validation parameters include <0.02% THD at 100 kHz, −70 dB off-isolation, and monotonic ron vs. VI/O voltage-confirmed in the SN74CBT3244CRGYR characterization data across its full operating range.

What are the recommended power-up sequencing requirements for the SN74CBT3244CRGYR to ensure high-impedance safety?

To guarantee high-impedance state at power-up, OE inputs (1OE and 2OE) must be held high until VCC reaches ≥3 V. TI recommends tying each OE to VCC through a ≤10-kΩ pullup resistor. This ensures the internal enable logic powers before the switch core, preventing momentary conduction. This requirement is specific to the SN74CBT3244CRGYR's architecture and is validated across all RGY-package production lots.