SZZA030E August   2021  – June 2022 CD4016B , CD4016B-MIL , CD4051B , CD4051B-MIL , CD4051B-Q1 , CD4052B , CD4052B-MIL , CD4053B , CD4053B-MIL , CD4053B-Q1 , CD4066B , CD4066B-MIL , CD4066B-Q1 , CD4067B , CD4067B-MIL , CD4097B , CD4097B-MIL , CD54HC4051 , CD54HC4052 , CD54HC4053 , CD54HC4066 , CD54HC4316 , CD54HC4351 , CD54HCT4051 , CD74HC4016 , CD74HC4051 , CD74HC4051-EP , CD74HC4051-Q1 , CD74HC4052 , CD74HC4053 , CD74HC4066 , CD74HC4067 , CD74HC4316 , CD74HC4351 , CD74HC4352 , CD74HCT4051 , CD74HCT4051-Q1 , CD74HCT4052 , CD74HCT4053 , CD74HCT4066 , CD74HCT4066-Q1 , CD74HCT4067 , CD74HCT4067-Q1 , CD74HCT4316 , CD74HCT4351 , LMH6580 , LMH6583 , LMH6586 , LMS4684 , MAX4594 , MAX4595 , MAX4596 , MAX4597 , MPC506 , MPC507 , MPC508 , MPC509 , MUX36D04 , MUX36D08 , MUX36S08 , MUX36S16 , MUX506 , MUX507 , MUX508 , MUX509 , SN3257-Q1 , SN54CBTD3384 , SN74AHC4066 , SN74AUC1G66 , SN74AUC2G53 , SN74AUC2G66 , SN74CB3Q16210 , SN74CB3Q16211 , SN74CB3Q16244 , SN74CB3Q16245 , SN74CB3Q16811 , SN74CB3Q3125 , SN74CB3Q3244 , SN74CB3Q3245 , SN74CB3Q3251 , SN74CB3Q3253 , SN74CB3Q3257 , SN74CB3Q3305 , SN74CB3Q3306A , SN74CB3Q3306A-EP , SN74CB3Q3345 , SN74CB3Q3384A , SN74CB3Q6800 , SN74CB3T16210 , SN74CB3T16210-Q1 , SN74CB3T16211 , SN74CB3T16212 , SN74CB3T1G125 , SN74CB3T1G125-Q1 , SN74CB3T3125 , SN74CB3T3245 , SN74CB3T3253 , SN74CB3T3257 , SN74CB3T3306 , SN74CB3T3383 , SN74CB3T3384 , SN74CBT16209A , SN74CBT16210 , SN74CBT16210C , SN74CBT16211A , SN74CBT16211C , SN74CBT16212A , SN74CBT16212C , SN74CBT16213 , SN74CBT16214 , SN74CBT16214C , SN74CBT162292 , SN74CBT16232 , SN74CBT16233 , SN74CBT16244 , SN74CBT16244C , SN74CBT16245 , SN74CBT16245C , SN74CBT16292 , SN74CBT16390 , SN74CBT16800C , SN74CBT16811C , SN74CBT16861 , SN74CBT1G125 , SN74CBT1G384 , SN74CBT3125 , SN74CBT3125C , SN74CBT3126 , SN74CBT3244 , SN74CBT3244C , SN74CBT3245A , SN74CBT3245C , SN74CBT3251 , SN74CBT3253 , SN74CBT3253C , SN74CBT3257 , SN74CBT3257C , SN74CBT3305C , SN74CBT3306 , SN74CBT3306C , SN74CBT3345 , SN74CBT3345C , SN74CBT3383 , SN74CBT3383C , SN74CBT3384A , SN74CBT3384C , SN74CBT34X245 , SN74CBT3861 , SN74CBT6800A , SN74CBT6800C , SN74CBT6845C , SN74CBTD16210 , SN74CBTD16211 , SN74CBTD1G125 , SN74CBTD1G384 , SN74CBTD3305C , SN74CBTD3306 , SN74CBTD3306C , SN74CBTD3384 , SN74CBTD3384C , SN74CBTD3861 , SN74CBTH16211 , SN74CBTK6800 , SN74CBTLV16210 , SN74CBTLV16211 , SN74CBTLV16212 , SN74CBTLV16292 , SN74CBTLV16800 , SN74CBTLV1G125 , SN74CBTLV1G125-Q1 , SN74CBTLV3125 , SN74CBTLV3126 , SN74CBTLV3245A , SN74CBTLV3251 , SN74CBTLV3253 , SN74CBTLV3257 , SN74CBTLV3257-EP , SN74CBTLV3383 , SN74CBTLV3384 , SN74CBTLV3857 , SN74CBTLV3861 , SN74CBTLV3861-Q1 , SN74CBTS16211 , SN74CBTS16212 , SN74CBTS3306 , SN74CBTS3384 , SN74CBTS6800 , SN74HC151-Q1 , SN74HC4066 , SN74HC4851 , SN74HC4851-Q1 , SN74HC4852 , SN74HC4852-Q1 , SN74LV4051A , SN74LV4051A-EP , SN74LV4051A-Q1 , SN74LV4052A , SN74LV4052A-EP , SN74LV4052A-Q1 , SN74LV4053A , SN74LV4053A-EP , SN74LV4053A-Q1 , SN74LV4066A , SN74LVC1G3157 , SN74LVC1G3157-Q1 , SN74LVC1G66 , SN74LVC1G66-Q1 , SN74LVC2G53 , SN74LVC2G66 , SN74LVC2G66-Q1 , SN74TVC16222A , SN74TVC3010 , SN74TVC3306 , TMUX1072 , TMUX1101 , TMUX1102 , TMUX1104 , TMUX1108 , TMUX1109 , TMUX1111 , TMUX1112 , TMUX1113 , TMUX1119 , TMUX1121 , TMUX1122 , TMUX1123 , TMUX1133 , TMUX1134 , TMUX1136 , TMUX1204 , TMUX1208 , TMUX1209 , TMUX1219 , TMUX1247 , TMUX1308 , TMUX1308-Q1 , TMUX1309 , TMUX136 , TMUX1511 , TMUX154E , TMUX1574 , TMUX4051 , TMUX4052 , TMUX4053 , TMUX6104 , TMUX6111 , TMUX6112 , TMUX6113 , TMUX6119 , TMUX6121 , TMUX6122 , TMUX6123 , TMUX6136 , TS12A12511 , TS12A44513 , TS12A44514 , TS12A44515 , TS12A4514 , TS12A4515 , TS12A4516 , TS12A4517 , TS3A225E , TS3A24157 , TS3A24159 , TS3A27518E , TS3A27518E-Q1 , TS3A44159 , TS3A4741 , TS3A4742 , TS3A4751 , TS3A5017 , TS3A5017-Q1 , TS3A5018 , TS3A5223 , TS5A1066 , TS5A12301E , TS5A2053 , TS5A2066 , TS5A21366 , TS5A22362 , TS5A22364 , TS5A22364-Q1 , TS5A22366 , TS5A23157 , TS5A23157-Q1 , TS5A23159 , TS5A23160 , TS5A23166 , TS5A23167 , TS5A26542 , TS5A3153 , TS5A3154 , TS5A3157 , TS5A3159 , TS5A3159-EP , TS5A3159-Q1 , TS5A3159A , TS5A3160 , TS5A3166 , TS5A3166-Q1 , TS5A3167 , TS5A3357 , TS5A3357-Q1 , TS5A3359 , TS5A4594 , TS5A4595 , TS5A4596 , TS5A4597 , TS5A4624 , TS5A623157 , TS5A63157 , TS5A6542 , TS5A9411 , TS5MP645 , TS5MP646 , TS5N118 , TS5N214 , TS5N412

 

  1.   Selecting the Correct Texas Instruments Signal Switch
  2.   Trademarks
  3. 1Introduction
    1. 1.1 Ideal Versus Non-Ideal Switch
  4. 2Basic Signal Switch Structure
    1. 2.1 NFET Switch
    2. 2.2 Transmission Gate Switch
    3. 2.3 NFET With Charge Pump
  5. 3Analog Versus Digital Signal Switches
    1. 3.1 Bidirectional Switches
    2. 3.2 Configuration and Channels
  6. 4Signal Switch Specifications and Features
  7. 5Texas Instruments Analog Signal Switches and Multiplexers Portfolio
    1. 5.1 Precision Switches and Multiplexers
    2. 5.2 Protection Switches and Multiplexers
    3. 5.3 General Purpose Switches and Multiplexers
    4. 5.4 Automotive Switches and Multiplexers
  8. 6Switches and Multiplexers Performance in Digital Signal Applications
  9. 7Applications
    1. 7.1 SPI Multiplexing
    2. 7.2 Multiplexing Signals to External ADC
    3. 7.3 Multiplexing Signals to External ADC in Fault Sensitive Conditions
    4. 7.4 Switchable Op Amp Gain Setting
    5. 7.5 Multiplexing Body Control Module (BCM) Inputs
    6. 7.6 High Current Range Selection Using External Resistor
    7. 7.7 Fault Protection in Factory Automation Control Systems
    8. 7.8 Sample and Hold Circuitry
  10. 8Summary
  11. 9Revision History
  12.   A Appendix A
    1.     A.1 Analog Performance – CD, HC, CBT, LVC, and LV
    2.     A.2 SN74CBT Characteristics
    3.     A.3 CD74HCT Characteristics
    4.     A.4 CD74HC Characteristics
    5.     A.5 SN74HC Characteristics
    6.     A.6 CD4066B Characteristics
    7.     A.7 LV-A Characteristics
    8.     A.8 LVC Characteristics
    9.     A.9 CBTLV Characteristics

2.1 NFET Switch

Figure 2-1 shows a simplified FET switch, which consists of an N-channel transistor and gate bias and enable circuitry. The switch is bidirectional; the source and drain are interchangeable (while operating, the side with the lowest VI/O is the source). TI CBT bus switches are this type.

GUID-3A6D3EF2-10C5-426C-9103-A186556807D7-low.gifFigure 2-1 N-channel FET Switch

For an N-channel FET to operate properly, the gate should be biased more positive than the magnitude of the signals to be passed. This is because the on-state resistance, RON (or RDS(ON) as it also is called), increases as the gate, minus source voltage, VGS, decreases. If the lowest VI/O signal approaches the magnitude of VCC, VGS decreases and RON increases (see Figure 2-2). The ability to maintain a low RON in a FET switch depends on maintaining VGS as large as possible. In many applications, this characteristic is not a problem, but the designer should be aware of the nonlinearity of this type of device.

GUID-1CF67F61-AD22-4889-8C6A-1B0C323228B4-low.gifFigure 2-2 On-State Resistance vs Lowest I/O Voltage for an N-channel FET Switch With VCC = 5 V

An N-channel FET can be used to implement a level translator. This switch can pass a signal from 0 V to VCC – VT, where VT is the threshold voltage of the NMOS. This characteristic can be used for down translation. For voltage-translation applications, the switch is required to translate efficiently over a wide frequency range and is required to maintain the proper signal level. For example, when translating from a 5-V TTL to a 3.3-V LVTTL signal, the switch is required to maintain the required VOH (output high voltage) and VOL (output low voltage) of 3.3-V LVTTL signal. One important consideration is that the switch can be used only for down translation, for example, high to low level. For low- to high-level translation, additional components (for example, pullup resistors) are required.