Texas Instruments SN74CB3Q3244PWRE4

Overview

SN74CB3Q3244 from Texas Instruments is a high-bandwidth 8-bit FET bus switch with dual 4-bit configurable channels, 4 Ω typical ON-state resistance, rail-to-rail 0–5 V switching at 3.3 V V_CC, and 5-V-tolerant I/Os-enabling signal gating in DDR memory interfaces and PCIe lane isolation.

For engineers reviewing the SN74CB3Q3244 datasheet, SN74CB3Q3244 pinout, SN74CB3Q3244 application, or SN74CB3Q3244 equivalent, key selection criteria include its 500 MHz bandwidth, I_off-enabled partial-power-down capability, low 3.5 pF OFF-state capacitance, and bidirectional zero-delay data flow across two independent 4-bit channels.

Technical Context

The SN74CB3Q3244 implements an internal charge-pump architecture to elevate gate voltage of pass transistors, ensuring flat r_on (4 Ω typ.) across 0–5 V signal swing and 2.3–3.6 V V_CC range. Its dual independent OE controls (1OE, 2OE) allow per-channel enable/disable for flexible bus segmentation.

Each channel supports bidirectional, near-zero propagation delay (<0.2 ns) switching with undervoltage clamp diodes on all control inputs and full JESD78 Class II latch-up immunity (>100 mA). The device maintains high-impedance isolation during power-off via I_off circuitry, preventing backflow current when V_CC = 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 thermal pad not present.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT3244PWR and SN74LVC1G3157DCKR, the SN74CB3Q3244 delivers superior bandwidth, flatter r_on, and robust I_off-based isolation-making it the only choice for high-reliability DDR memory gating and PCIe lane management where signal integrity and power sequencing matter.

Availability

SN74CB3Q3244 is available at Aetrix Electronics and suitable for DDR memory interleaving, PCIe lane isolation, JTAG test multiplexing, and differential signal gating requiring stable component supply and long-term industrial lifecycle support.

Supply support for SN74CB3Q3244 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-performance signal-path components.

The SN74CB3Q3244 belongs to TI's CB3Q family of high-bandwidth FET bus switches, engineered specifically for low-distortion, rail-to-rail signal routing in memory, networking, and computing infrastructure where timing precision and voltage flexibility are critical.

FAQ

What is the maximum signal frequency supported by the SN74CB3Q3244?

The SN74CB3Q3244 supports up to 500 MHz bandwidth, verified under conditions of 3.3 V V_CC, 0–5 V signal swing, and matched 50 Ω source/load. This performance is enabled by its charge-pump architecture and low 3.5 pF OFF-state capacitance, making SN74CB3Q3244 suitable for DDR2/3 address bus gating and high-speed serial link isolation.

Does the SN74CB3Q3244 support partial-power-down operation?

Yes, the SN74CB3Q3244 features I_off circuitry that limits leakage to 1 µA when V_CC = 0 V, enabling safe partial-power-down mode. This prevents damaging current backflow between powered and unpowered subsystems-critical for hot-swap applications and power-gated memory controllers using SN74CB3Q3244.

Can the SN74CB3Q3244 interface 5-V signals while operating from a 3.3-V supply?

Yes, the SN74CB3Q3244 has 5-V-tolerant I/Os rated to 7 V, allowing 0–5 V signaling on both A and B ports while powered from 2.3–3.6 V V_CC. This eliminates level shifters in mixed-voltage systems such as legacy peripheral interfacing, making SN74CB3Q3244 ideal for bridging 3.3-V controllers to 5-V sensors or displays.

What is the ON-state resistance (r_on) of the SN74CB3Q3244 and how does it vary?

The SN74CB3Q3244 has a typical r_on of 4 Ω at V_CC = 3 V and I_O = −15 mA, with flat response across 0–5 V input voltage due to its internal charge pump. Measured r_on stays within 4–8 Ω over full operating range, ensuring consistent signal integrity-unlike non-charge-pump switches where r_on rises sharply near rail extremes.

How are the two 4-bit channels controlled on the SN74CB3Q3244?

The SN74CB3Q3244 uses separate active-low enable inputs: 1OE controls pins 1A1–1A4 ↔ 1B1–1B4, and 2OE controls 2A1–2A4 ↔ 2B1–2B4. When an OE is low, its associated 4-bit path is conductive; when high, the path enters high-impedance state. This allows independent channel management in applications like dual-bank memory control using SN74CB3Q3244.