Texas Instruments SN74CBTK6800PW

Overview

SN74CBTK6800PW from Texas Instruments is a 10-bit FET bus switch with precharged outputs and active-clamp undershoot protection, designed for live-insertion applications in backplane and hot-swap systems. It features 5-Ω on-state resistance, TTL-compatible inputs, and clamps I/O undershoots down to –2 V. The device connects A and B ports bidirectionally when enabled and precharges B-port outputs to a user-selectable BIASV voltage during power-off or disable.

For engineers reviewing the SN74CBTK6800PW datasheet, SN74CBTK6800PW pinout, SN74CBTK6800PW application, or SN74CBTK6800PW equivalent, key selection criteria include its 5-Ω r_on, active-clamp undershoot protection to –2 V, 0.25 ns typical propagation delay, precharge functionality at BIASV, and TSSOP-24 packaging suitable for high-density board layouts.

Technical Context

The SN74CBTK6800PW implements a single 10-bit bidirectional FET switch controlled by one active-low ON input. Its internal architecture includes integrated active-clamp circuits on all I/O pins that supply current from V_CC to limit undershoot transients below –2 V, preventing pass-transistor turn-on during signal faults.

When disabled (ON = high) or unpowered (V_CC = 0 V), the B port is precharged to BIASV via an internal ~10-kΩ equivalent resistor, minimizing noise and signal distortion during live insertion. The device operates across V_CC = 4 V to 5.5 V and supports BIASV from 1.3 V to V_CC, enabling compatibility with mixed-voltage system interfaces.

Key Specifications

Pinout & Package

TSSOP-24 package (PW), 7.9 mm × 4.5 mm × 1.2 mm max height, lead-free NIPDAU 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 SN74CBTK6800PW, SN74CBT16210DL offers lower cost but omits critical live-insertion features, while SN74LVC1G3157DCKR provides compact single-channel switching at higher r_on and no system-level protection-neither matches the SN74CBTK6800PW's integrated precharge, active clamping, and 10-bit parallel architecture.

Availability

SN74CBTK6800PW is available at Aetrix Electronics and suitable for backplane hot-swap interfaces, PCI add-in card isolation, modular test equipment interconnect, and redundant power supply monitoring buses requiring stable component supply and long-term industrial availability.

Supply support for SN74CBTK6800PW 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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and communications markets.

The SN74CBTK6800PW belongs to TI's CBT family of high-speed CMOS bus switches, engineered specifically for live-insertion, hot-swap, and high-integrity signal routing in mission-critical infrastructure equipment.

FAQ

What is the maximum undershoot voltage the SN74CBTK6800PW can safely clamp?

The SN74CBTK6800PW actively clamps I/O undershoots down to –2 V, as verified in the undershoot characteristics table (V_OUTU = –2 V min). This is achieved by sourcing current from V_CC through internal clamp circuitry, preventing the pass transistor from turning on during negative transients. The SN74CBTK6800PW maintains this clamping behavior across its full operating temperature range (–40°C to 85°C) and supply voltage range (4 V to 5.5 V).

Does the SN74CBTK6800PW require external pull-up resistors on the B port?

No, the SN74CBTK6800PW does not require external pull-up resistors on the B port. When the ON input is high or V_CC is 0 V, the B port is internally precharged to the BIASV voltage through an equivalent 10-kΩ resistor. This built-in precharge eliminates the need for discrete components and ensures a known, stable DC level during live insertion, power-down, or hot-swap events-key to reliable operation of the SN74CBTK6800PW in backplane systems.

What is the recommended BIASV voltage range for use with 3.3-V logic systems?

For 3.3-V logic systems, the recommended BIASV voltage range for the SN74CBTK6800PW is 1.3 V to 3.3 V, per the recommended operating conditions table. Setting BIASV to 3.3 V ensures the B port is precharged to the full logic-high level, minimizing transition noise and ensuring compatibility with downstream 3.3-V receivers. The SN74CBTK6800PW supports this range across its full operating temperature and supply voltage specifications, making it suitable for mixed-voltage interface designs.

Can the SN74CBTK6800PW operate with a 2.5-V supply voltage?

No, the SN74CBTK6800PW cannot operate with a 2.5-V supply voltage. Its recommended operating V_CC range is strictly 4 V to 5.5 V, and absolute maximum ratings specify a minimum V_CC of –0.5 V-but functional operation below 4 V is not guaranteed or characterized. Attempting to power the SN74CBTK6800PW at 2.5 V may result in undefined switching behavior, excessive r_on, or failure to activate the active-clamp circuit. For 2.5-V systems, alternate bus switches such as the SN74LVC2G66 must be evaluated.

How does the SN74CBTK6800PW handle power sequencing during hot-swap events?

The SN74CBTK6800PW handles power sequencing during hot-swap events through two integrated mechanisms: first, its power-off disable feature limits I_off to ≤20 µA when V_CC = 0 V, preventing back-driving of the A or B ports; second, the B port is automatically precharged to BIASV via an internal ~10-kΩ resistor whenever ON is high or V_CC is absent. This ensures the SN74CBTK6800PW presents a known, noise-immune state during mechanical mating-critical for NEBS-compliant telecom equipment and enterprise servers.