Texas Instruments SN74CB3Q3244PWR

Overview

SN74CB3Q3244PWR from Texas Instruments is a high-bandwidth 8-bit FET bus switch organized as two independent 4-bit switches, featuring 4 Ω typical ON-state resistance (ron), rail-to-rail 0–5 V switching at 3.3-V VCC, and 5-V-tolerant I/Os with device powered up or down. It enables bidirectional data flow with near-zero propagation delay (0.12 ns typical) and supports memory interleaving and bus isolation in high-speed computing systems.

For engineers reviewing the SN74CB3Q3244PWR datasheet, SN74CB3Q3244PWR pinout, SN74CB3Q3244PWR application, or SN74CB3Q3244PWR equivalent, key selection criteria include its 2.3–3.6 V VCC range, 3.5 pF typical OFF-state I/O capacitance, Ioff partial-power-down support, and TSSOP-20 package compatibility with high-density PCB layouts.

Technical Context

The SN74CB3Q3244PWR employs an internal charge pump to elevate gate voltage of pass transistors, ensuring flat ron across input voltage (0–5 V) and supply range (2.3–3.6 V). Its dual 4-bit architecture allows flexible configuration as two independent switches or one 8-bit switch via separate 1OE/2OE controls.

Each switch channel provides undervoltage clamp diodes on control inputs, supports TTL/5-V/3.3-V CMOS drive compatibility, and guarantees isolation during power-off via Ioff circuitry that limits backflow current to ≤1 µA when VCC = 0 V.

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 6.5 mm × 4.4 mm body, 0.65 mm pitch, 1.2 mm max height, exposed pad not present, RoHS-compliant NiPdAu lead finish, MSL Level-1 (unlimited reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBTLV3244PWR and TS3USB30EVMR, the SN74CB3Q3244PWR uniquely combines 8-bit dual-switch flexibility, 4 Ω flat ron, 5-V I/O tolerance, and Ioff-enabled partial-power-down-making it the only option supporting mixed-voltage memory expansion and hot-plug isolation in industrial compute platforms.

Availability

SN74CB3Q3244PWR is available at Aetrix Electronics and suitable for memory interleaving, bus isolation, differential signal interface, and low-distortion signal gating applications requiring stable component supply and long-term industrial lifecycle support.

Supply support for SN74CB3Q3244PWR 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 electronic components.

The SN74CB3Q3244PWR belongs to TI's CB3Q family of high-bandwidth FET bus switches, engineered specifically for low-distortion, rail-to-rail signal routing in broadband communications, networking infrastructure, and data-intensive computing systems.

FAQ

What is the maximum operating frequency supported by the SN74CB3Q3244PWR?

The SN74CB3Q3244PWR supports up to 500 MHz high-bandwidth data path operation, verified under load conditions with low ON-state resistance and minimal signal distortion. Its 20 MHz maximum OE switching frequency and 0.12 ns typical propagation delay make it suitable for DDR2/DDR3 memory clock domains and high-speed serial link gating. The 500 MHz bandwidth applies to continuous analog/digital signal transmission through the enabled switch path.

Does the SN74CB3Q3244PWR support partial-power-down mode?

Yes, the SN74CB3Q3244PWR features Ioff circuitry that actively limits current backflow to ≤1 µA when VCC = 0 V, enabling safe partial-power-down operation. This allows the device to remain connected to live 5-V I/O buses while its local supply is off-critical for hot-swap backplanes and modular system architectures. The high-impedance state is maintained without external biasing.

Can the SN74CB3Q3244PWR interface between 1.8-V and 5-V logic domains?

Yes, the SN74CB3Q3244PWR supports 0–5-V signaling on all A/B I/O ports regardless of VCC level (2.3–3.6 V), enabling direct 1.8-V ↔ 5-V level translation without external components. Its 5-V-tolerant I/Os and rail-to-rail switching capability allow bidirectional signal transfer between mixed-voltage subsystems-such as connecting a 1.8-V FPGA core to a 5-V legacy peripheral bus.

What is the thermal performance of the SN74CB3Q3244PWR in its TSSOP-20 package?

The SN74CB3Q3244PWR in TSSOP-20 (PW) package has a thermal impedance θJA of 83°C/W, measured per JESD 51-5. At maximum rated ICC (2 mA) and worst-case ambient (85°C), junction temperature rise remains below 17°C-well within safe operating limits. No heatsink or thermal pad is required for standard operation, though PCB copper area under the package improves margin.

How does the charge pump in the SN74CB3Q3244PWR improve performance compared to standard FET switches?

The integrated charge pump in the SN74CB3Q3244PWR elevates the gate voltage of pass transistors above VCC, ensuring low and flat ON-state resistance (4 Ω typical) across the full 0–5-V I/O voltage range. This eliminates ron variation seen in non-pumped switches-where resistance can double at low VI/O-resulting in consistent signal amplitude, reduced timing skew, and superior high-frequency response up to 500 MHz.