NXP Semiconductors CBT3126DS,118

Overview

CBT3126DS,118 from NXP Semiconductors is a quad FET bus switch with independent line control, designed for high-speed bidirectional signal routing in 5 V TTL-compatible digital systems. It features four independent switches (1A↔1B, 2A↔2B, 3A↔3B, 4A↔4B), 5 Ω typical ON resistance at 4.5 V, sub-0.25 ns propagation delay, and operates across −40 °C to +85 °C. It is used in address/data bus isolation, hot-swap I/O buffering, and logic-level translation.

For engineers reviewing the CBT3126DS,118 datasheet, CBT3126DS,118 pinout, CBT3126DS,118 application, or CBT3126DS,118 equivalent, key selection criteria include guaranteed 5 Ω R_ON at 4.5 V, <4.5 ns enable time, SSOP16 package compatibility, and compliance with JEDEC JESD78 latch-up and JESD22 ESD standards.

Technical Context

The CBT3126DS,118 implements four independent single-pole single-throw (SPST) analog switches using low-threshold N-channel FETs, each controlled by a dedicated OE input. Switching is bidirectional with no inherent directionality - signal flow is determined solely by external circuit topology.

Each channel exhibits minimal voltage drop (<0.2 V at 30 mA), negligible propagation delay (≤0.25 ns), and fast enable/disable timing (t_en ≤4.5 ns, t_dis ≤5.4 ns). The device requires only a single 4.5–5.5 V supply and draws ≤3 µA quiescent current, with no biasing or termination resistors needed.

Key Specifications

Pinout & Package

CBT3126DS,118 is housed in a plastic shrink small outline package (SSOP16) with 16 leads, 3.9 mm body width, and 0.635 mm lead pitch (SOT519-1). Pin 1 is marked by a notch or dot; pin 1 index is located at top-left corner when viewed top-down with marking side up.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT3126PWR and 74LVC1G3157GW,125, the CBT3126DS,118 offers native SSOP16 compatibility, lowest propagation delay, and highest latch-up immunity - making it optimal for timing-critical industrial bus isolation where footprint reuse and robustness are primary concerns.

Availability

CBT3126DS,118 is available at Aetrix Electronics and suitable for PCI bus isolation, hot-swap I/O buffering, and memory address multiplexing requiring stable component supply, long-term industrial lifecycle support, and consistent SSOP16 packaging.

Supply support for CBT3126DS,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

NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT applications.

The CBT3126DS,118 belongs to NXP's legacy logic bus switch family, engineered specifically for high-speed, low-distortion signal routing in 5 V digital systems where timing integrity and robustness outweigh programmability or voltage flexibility.

FAQ

What is the maximum continuous current rating per switch in the CBT3126DS,118?

The CBT3126DS,118 supports a maximum continuous switch current (I_SW) of 128 mA per channel, as specified in Table 4 of the datasheet under limiting values. This rating applies across the full operating temperature range (−40 °C to +85 °C) and assumes proper PCB thermal design. Exceeding this current may cause thermal runaway or permanent damage to the internal FET structure.

Does the CBT3126DS,118 require external pull-up or pull-down resistors on its OE inputs?

No, the CBT3126DS,118 does not require external pull-up or pull-down resistors on its OE inputs. Its TTL-compatible input thresholds (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V) allow direct connection to standard logic outputs. However, all unused OE inputs must be held at either V_CC or GND - floating inputs are prohibited and may cause unpredictable switching behavior or increased ICC.

Can the CBT3126DS,118 operate with a 3.3 V supply voltage?

No, the CBT3126DS,118 is not rated for 3.3 V operation. Its recommended operating supply voltage is strictly 4.5 V to 5.5 V (Table 5), and absolute maximum V_CC is +7.0 V. At 3.3 V, R_ON increases significantly (>20 Ω), t_pd degrades beyond specification, and input thresholds become unreliable. For 3.3 V systems, consider NXP's 74LVC-series alternatives instead of the CBT3126DS,118.

What is the significance of the "n.c." pins (1 and 9) on the CBT3126DS,118 SSOP16 package?

Pins 1 and 9 of the CBT3126DS,118 are designated "n.c." (no connection) and have no internal bond wire or silicon connection. They exist solely for mechanical symmetry and package manufacturability. These pins must remain unconnected - routing traces to them or tying them to any potential introduces parasitic capacitance and risks mechanical stress-induced solder joint failure. Their presence does not indicate future functionality or test points.

How does the CBT3126DS,118 handle bidirectional signal flow between A and B terminals?

Each channel of the CBT3126DS,118 functions as a symmetric, bidirectional analog switch - there is no intrinsic directionality. Signal flow from A to B or B to A is electrically identical, with matched R_ON, capacitance, and timing. The device imposes no voltage polarity restrictions: signals can swing from GND to V_CC (or slightly beyond, within absolute max ratings), and DC coupling is preserved across the switch when enabled.