)
Typical)For additional information regarding the performance characteristics of the CB3Q family, refer to the TI application report, CBT-C, CB3T, and CB3Q Signal-Switch Families, literature number SCDA008.
The SN74CB3Q6800 is a high-bandwidth FET bus switch utilizing a charge pump to elevate the gate voltage of the pass transistor, providing a low and flat ON-state resistance (ron). The low and flat ON-state resistance allows for minimal propagation delay and supports rail-to-rail switching on the data input/output (I/O) ports. The device also features low data I/O capacitance to minimize capacitive loading and signal distortion on the data bus. Specifically designed to support high-bandwidth applications, the SN74CB3Q6800 provides an optimized interface solution ideally suited for broadband communications, networking, and data-intensive computing systems.
The SN74CB3Q6800 is a 10-bit bus switch with a single output-enable (ON\) input. When ON\ is low, the 10-bit
bus switch is ON and the A port is connected to the B port, allowing bidirectional data flow between ports. When
ON\ is high, the 10-bit bus switch is OFF and a high-impedance state exists between the A and B ports. The B
port is precharged to bias voltage (BIASV) through the equivalent of a 10-k resistor when ON\ is high, or if the
device is powered down (VCC = 0 V).
During insertion (or removal) of a card into (or from) an active bus, the card’s output voltage may be close to GND. When the connector pins make contact, the card’s parasitic capacitance tries to force the bus signal to GND, creating a possible glitch on the active bus. This glitching effect can be reduced by using a bus switch with precharged bias voltage (BIASV) of the bus switch equal to the input threshold voltage level of the receivers on the active bus. This method will ensure that any glitch produced by insertion (or removal) of the card will not cross the input threshold region of the receivers on the active bus, minimizing the effects of live-insertion noise.
This device is fully specified for partial-power-down applications using Ioff. The Ioff circuitry prevents damaging current backflow through the device when it is powered down. The device has isolation during power off.
To ensure the high-impedance state during power up or power down, ON\ should be tied to VCC through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.
| Type | Title | Date | ||
|---|---|---|---|---|
| * | Data sheet | SN74CB3Q6800 datasheet (Rev. A) | 20 Nov 2003 | |
| Application note | Selecting the Correct Texas Instruments Signal Switch (Rev. E) | PDF | HTML | 02 Jun 2022 | |
| Application note | Multiplexers and Signal Switches Glossary (Rev. B) | PDF | HTML | 01 Dec 2021 | |
| Application note | CBT-C, CB3T, and CB3Q Signal-Switch Families (Rev. C) | PDF | HTML | 19 Nov 2021 | |
| Application brief | Eliminate Power Sequencing with Powered-off Protection Signal Switches (Rev. C) | PDF | HTML | 06 Jan 2021 | |
| Selection guide | Logic Guide (Rev. AB) | 12 Jun 2017 | ||
| Application note | Understanding and Interpreting Standard-Logic Data Sheets (Rev. C) | 02 Dec 2015 | ||
| User guide | LOGIC Pocket Data Book (Rev. B) | 16 Jan 2007 | ||
| More literature | Digital Bus Switch Selection Guide (Rev. A) | 10 Nov 2004 | ||
| Application note | Semiconductor Packing Material Electrostatic Discharge (ESD) Protection | 08 Jul 2004 | ||
| User guide | Signal Switch Data Book (Rev. A) | 14 Nov 2003 | ||
| Application note | Bus FET Switch Solutions for Live Insertion Applications | 07 Feb 2003 |
For additional terms or required resources, click any title below to view the detail page where available.
The EVM-LEADED1 board allows for quick testing and bread boarding of TI's common leaded packages. The board has footprints to convert TI's D, DBQ, DCT,DCU, DDF, DGS, DGV, and PW surface mount packages to 100mil DIP headers.
| Package | Pins | CAD symbols, footprints & 3D models |
|---|---|---|
| SSOP (DBQ) | 24 | Ultra Librarian |
| TSSOP (PW) | 24 | Ultra Librarian |
| TVSOP (DGV) | 24 | Ultra Librarian |
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