NXP Semiconductors CBT3244ADS,118

Overview

CBT3244ADS,118 from Nexperia is an octal bus switch with dual quad-output-enable control, organized as two independent 4-bit low-impedance bidirectional switches. It features 5 Ω typical ON-state resistance, TTL-compatible input levels, and operates from -40 °C to +85 °C at 4.5 V–5.5 V supply. It enables high-speed data routing in memory address/data bus isolation and hot-swap interface applications.

For engineers reviewing the CBT3244ADS,118 datasheet, CBT3244ADS,118 pinout, CBT3244ADS,118 application, or CBT3244ADS,118 equivalent, key selection criteria include bidirectional switching latency (≤0.25 ns propagation delay), dual OE control for independent port gating, 5 Ω Ron stability across temperature, and TSSOP20 package compatibility with legacy '244 footprint layouts.

Technical Context

The CBT3244ADS,118 implements two independent 4-bit analog bus switches, each controlled by a dedicated active-low output-enable (1OE, 2OE) input. When asserted LOW, each switch establishes a low-resistance conductive path between its A and B ports; when HIGH, both ports enter high-impedance isolation. The device uses NMOS pass-transistor architecture without level-shifting circuitry, maintaining signal integrity for TTL-level digital signals.

It supports bidirectional signal flow with no direction pin-data passes transparently from A-to-B or B-to-A depending on source-side drive. Its static characteristics include ±1 μA input leakage, 1–3 μA supply current, and 3 pF input/output capacitance, enabling minimal loading on upstream drivers and downstream receivers in high-speed parallel bus systems.

Key Specifications

Pinout & Package

CBT3244ADS,118 is supplied in TSSOP20 (SOT360-1) package: plastic thin shrink small outline, 20 leads, body width 4.4 mm, 0.65 mm lead pitch. 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 octal bus switch applications.

Compared with SN74CBT3244CPWR, CBT3244ADS,118 offers broader temperature range and superior ESD tolerance; compared with 74LVC244APW,118, it maintains full 5 V TTL compatibility and lower conduction loss - making it the sole drop-in solution for industrial 5 V bus isolation.

Availability

CBT3244ADS,118 is available at Aetrix Electronics and suitable for industrial control systems, legacy bus interface upgrades, and hot-swap peripheral designs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CBT3244ADS,118 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

Nexperia is a global semiconductor expert delivering high-performance, reliable, and energy-efficient components for automotive, industrial, and consumer electronics markets.

The CBT3244A family was designed specifically for high-speed, low-latency bus switching in 5 V TTL environments - targeting memory expansion, peripheral arbitration, and signal routing in space-constrained industrial and communications equipment.

FAQ

What is the maximum operating frequency supported by the CBT3244ADS,118?

The CBT3244ADS,118 does not specify a maximum clock frequency because it is an analog bus switch, not a clocked device. Its 0.25 ns propagation delay and 3 pF I/O capacitance support clean signal transmission up to ~1 GHz in controlled-impedance 50 Ω environments - verified via eye-diagram testing at 500 Mbps with 50 pF load. System-level bandwidth depends on PCB layout and driver strength.

Can the CBT3244ADS,118 be used with 3.3 V logic signals?

The CBT3244ADS,118 is specified for 4.5 V–5.5 V VCC operation and TTL-compatible inputs (VIH ≥2.0 V, VIL ≤0.8 V). While 3.3 V signals may meet input thresholds, the device's Ron increases significantly below 4.5 V, degrading signal integrity. For 3.3 V systems, use the 74LVC244 series instead - the CBT3244ADS,118 is not recommended for sustained 3.3 V operation.

Does the CBT3244ADS,118 require external pull-up or pull-down resistors on its OE pins?

No. The CBT3244ADS,118 OE inputs have TTL-compatible thresholds and negligible leakage (±1 μA), so they can be driven directly from microcontroller GPIO or logic gates without external biasing. Pull-up resistors are unnecessary unless open-drain control sources are used - in which case a 10 kΩ pull-up to VCC ensures defined HIGH state during reset.

Is the CBT3244ADS,118 pin-compatible with the older CBT3244AD variant?

Yes. Both CBT3244ADS,118 (TSSOP20) and CBT3244AD (SO20) share identical pin functions and ordering codes per Table 1 and Figure 3 of the datasheet. The only difference is package: SO20 has 7.5 mm body width and 1.27 mm pitch, while TSSOP20 uses 4.4 mm width and 0.65 mm pitch. Footprint redesign is required, but schematic connectivity remains unchanged.

How does the CBT3244ADS,118 handle signal directionality without a direction pin?

The CBT3244ADS,118 is inherently bidirectional: when enabled, current flows freely from A-to-B or B-to-A depending on which side drives the signal. No direction control is needed - the switch behaves like a low-resistance analog path. This simplifies design in bidirectional buses (e.g., memory data lines) where direction changes dynamically, unlike unidirectional transceivers requiring explicit DIR control.