SCHA005B January   2015  – December 2022 74AC11074 , 74AC16373 , 74AC16374 , 74ACT11074 , 74ACT11373 , 74ACT11374 , 74ACT16373 , 74ACT16374 , 74ACT16823 , 74ACT16841 , CD4006B-MIL , CD4013B , CD4013B-MIL , CD4014B , CD4014B-MIL , CD4015B , CD4015B-MIL , CD40174B , CD40174B-MIL , CD40175B , CD40175B-MIL , CD40194B , CD4021B , CD4021B-MIL , CD4021B-Q1 , CD4027B , CD4027B-MIL , CD4031B , CD4031B-MIL , CD4034B , CD4034B-MIL , CD4035B , CD4035B-MIL , CD4042B , CD4042B-MIL , CD4043B , CD4043B-MIL , CD4044B , CD4044B-MIL , CD4076B , CD4076B-MIL , CD4094B , CD4094B-MIL , CD4099B , CD4099B-MIL , CD4508B , CD4508B-MIL , CD4517B , CD4517B-MIL , CD4724B , CD4724B-MIL , CD54AC109 , CD54AC112 , CD54AC164 , CD54AC273 , CD54AC299 , CD54AC373 , CD54AC374 , CD54AC573 , CD54AC574 , CD54AC74 , CD54ACT109 , CD54ACT112 , CD54ACT164 , CD54ACT174 , CD54ACT273 , CD54ACT299 , CD54ACT373 , CD54ACT374 , CD54ACT573 , CD54ACT574 , CD54ACT74 , CD54HC107 , CD54HC109 , CD54HC112 , CD54HC164 , CD54HC165 , CD54HC166 , CD54HC173 , CD54HC174 , CD54HC175 , CD54HC194 , CD54HC259 , CD54HC273 , CD54HC299 , CD54HC373 , CD54HC374 , CD54HC377 , CD54HC4015 , CD54HC4094 , CD54HC533 , CD54HC534 , CD54HC563 , CD54HC564 , CD54HC573 , CD54HC574 , CD54HC597 , CD54HC73 , CD54HC74 , CD54HC75 , CD54HCT109 , CD54HCT112 , CD54HCT164 , CD54HCT165 , CD54HCT166 , CD54HCT173 , CD54HCT174 , CD54HCT175 , CD54HCT259 , CD54HCT273 , CD54HCT299 , CD54HCT373 , CD54HCT374 , CD54HCT377 , CD54HCT533 , CD54HCT534 , CD54HCT564 , CD54HCT573 , CD54HCT574 , CD54HCT74 , CD54HCT75 , CD74AC109 , CD74AC112 , CD74AC164 , CD74AC174 , CD74AC175 , CD74AC273 , CD74AC323 , CD74AC373 , CD74AC374 , CD74AC534 , CD74AC573 , CD74AC574 , CD74AC74 , CD74ACT109 , CD74ACT112 , CD74ACT164 , CD74ACT174 , CD74ACT175 , CD74ACT273 , CD74ACT299 , CD74ACT373 , CD74ACT374 , CD74ACT573 , CD74ACT574 , CD74ACT74 , CD74FCT273 , CD74FCT374 , CD74FCT843A , CD74HC107 , CD74HC109 , CD74HC112 , CD74HC164 , CD74HC165 , CD74HC166 , CD74HC173 , CD74HC174 , CD74HC175 , CD74HC194 , CD74HC195 , CD74HC259 , CD74HC273 , CD74HC299 , CD74HC373 , CD74HC374 , CD74HC377 , CD74HC4015 , CD74HC4094 , CD74HC533 , CD74HC534 , CD74HC563 , CD74HC564 , CD74HC573 , CD74HC574 , CD74HC595 , CD74HC597 , CD74HC670 , CD74HC73 , CD74HC74 , CD74HC75 , CD74HCT107 , CD74HCT109 , CD74HCT112 , CD74HCT164 , CD74HCT165 , CD74HCT166 , CD74HCT173 , CD74HCT174 , CD74HCT175 , CD74HCT194 , CD74HCT259 , CD74HCT273 , CD74HCT299 , CD74HCT373 , CD74HCT374 , CD74HCT377 , CD74HCT4094 , CD74HCT533 , CD74HCT534 , CD74HCT563 , CD74HCT564 , CD74HCT573 , CD74HCT574 , CD74HCT574-EP , CD74HCT597 , CD74HCT670 , CD74HCT73 , CD74HCT74 , CD74HCT75 , CY54FCT273T , CY54FCT373T , CY54FCT374T , CY54FCT377T , CY54FCT573T , CY54FCT574T , CY54FCT841T , CY74FCT2373T , CY74FCT2573T , CY74FCT2574T , CY74FCT273T , CY74FCT373T , CY74FCT374T , CY74FCT573T , CY74FCT574T , SN54107 , SN54166 , SN54173 , SN5472 , SN5476 , SN54ABT16373A , SN54ABT16374A , SN54ABT273 , SN54ABT373 , SN54ABT374 , SN54ABT377 , SN54ABT533 , SN54ABT534 , SN54ABT573 , SN54ABT574 , SN54ABT821 , SN54ABT823 , SN54ABT841 , SN54ABT843 , SN54AC373 , SN54AC373-SP , SN54AC374 , SN54AC574 , SN54AC74 , SN54AC74-SP , SN54ACT16373 , SN54ACT373 , SN54ACT373-SP , SN54ACT374 , SN54ACT374-SP , SN54ACT573 , SN54ACT74 , SN54AHC273 , SN54AHC373 , SN54AHC374 , SN54AHC573 , SN54AHC574 , SN54AHC74 , SN54AHCT373 , SN54AHCT374 , SN54AHCT573 , SN54AHCT574 , SN54AHCT74 , SN54ALS109A , SN54ALS112A , SN54ALS174 , SN54ALS175 , SN54ALS259 , SN54ALS273 , SN54ALS29821 , SN54ALS299 , SN54ALS323 , SN54ALS373A , SN54ALS374A , SN54ALS563B , SN54ALS564B , SN54ALS573C , SN54ALS574B , SN54ALS576B , SN54ALS580B , SN54ALS74A , SN54ALS873B , SN54ALS874B , SN54ALS996 , SN54AS174 , SN54AS175B , SN54AS374 , SN54AS573A , SN54AS574 , SN54AS74A , SN54AS821A , SN54AS823A , SN54AS825A , SN54BCT373 , SN54BCT374 , SN54BCT574 , SN54BCT8374A , SN54F109 , SN54F373 , SN54F374 , SN54F74 , SN54HC109 , SN54HC109-SP , SN54HC112 , SN54HC164 , SN54HC164-SP , SN54HC165 , SN54HC166 , SN54HC166-SP , SN54HC174 , SN54HC175 , SN54HC195 , SN54HC259 , SN54HC273 , SN54HC273-DIE , SN54HC273-SP , SN54HC373 , SN54HC373-DIE , SN54HC373-SP , SN54HC374 , SN54HC374-SP , SN54HC377 , SN54HC573A , SN54HC573A-SP , SN54HC574 , SN54HC595 , SN54HC595-SP , SN54HC74 , SN54HC74-SP , SN54HCT373 , SN54HCT373-SP , SN54HCT374 , SN54HCT74 , SN54LS109A , SN54LS112A , SN54LS164 , SN54LS164-SP , SN54LS165A , SN54LS165A-SP , SN54LS166A , SN54LS173A , SN54LS174 , SN54LS175 , SN54LS194A , SN54LS195A , SN54LS273 , SN54LS273-SP , SN54LS279A , SN54LS299 , SN54LS323 , SN54LS373 , SN54LS373-SP , SN54LS374 , SN54LS375 , SN54LS377 , SN54LS378 , SN54LS379 , SN54LS595 , SN54LS597 , SN54LS670 , SN54LS673 , SN54LS674 , SN54LS73A , SN54LS74A , SN54LS74A-SP , SN54LS75 , SN54LS76A , SN54LS91 , SN54LVC373A , SN54LVC374A , SN54LVC573A , SN54LVC574A , SN54LVC74A , SN54LVC74A-SP , SN54LVTH162373-SP , SN54LVTH162374-SP , SN54LVTH16373 , SN54LVTH373 , SN54LVTH374 , SN54LVTH573 , SN54LVTH574 , SN54LVTH574-SP , SN54S112 , SN54S174 , SN54S175 , SN54S194 , SN54S373 , SN54S374 , SN54S74 , SN74ABT162823A , SN74ABT162841 , SN74ABT16373A , SN74ABT16373A-EP , SN74ABT16374A , SN74ABT16821 , SN74ABT16823 , SN74ABT16841 , SN74ABT16843 , SN74ABT273 , SN74ABT373 , SN74ABT374A , SN74ABT377A , SN74ABT533A , SN74ABT534A , SN74ABT573A , SN74ABT574A , SN74ABT821A , SN74ABT823 , SN74ABT841A , SN74ABT843 , SN74ABTH162260 , SN74ABTH16260 , SN74ABTH16823 , SN74AC373 , SN74AC373-EP , SN74AC374 , SN74AC533 , SN74AC534 , SN74AC563 , SN74AC564 , SN74AC573 , SN74AC574 , SN74AC74 , SN74AC74-EP , SN74ACT16373-EP , SN74ACT16374-EP , SN74ACT373 , SN74ACT373-EP , SN74ACT374 , SN74ACT533 , SN74ACT534 , SN74ACT563 , SN74ACT564 , SN74ACT573 , SN74ACT574 , SN74ACT74 , SN74ACT74-EP , SN74AHC16373 , SN74AHC16374 , SN74AHC174 , SN74AHC273 , SN74AHC373 , SN74AHC374 , SN74AHC573 , SN74AHC574 , SN74AHC594 , SN74AHC595 , SN74AHC595-Q1 , SN74AHC74 , SN74AHC74-EP , SN74AHC74Q-Q1 , SN74AHCT16373 , SN74AHCT16374 , SN74AHCT174 , SN74AHCT273 , SN74AHCT373 , SN74AHCT374 , SN74AHCT573 , SN74AHCT574 , SN74AHCT594 , SN74AHCT595 , SN74AHCT74 , SN74AHCT74-EP , SN74AHCT74Q-Q1 , SN74ALS109A , SN74ALS112A , SN74ALS164A , SN74ALS165 , SN74ALS166 , SN74ALS174 , SN74ALS175 , SN74ALS259 , SN74ALS273 , SN74ALS29821 , SN74ALS299 , SN74ALS323 , SN74ALS373A , SN74ALS374A , SN74ALS533A , SN74ALS534A , SN74ALS563B , SN74ALS564B , SN74ALS573C , SN74ALS574B , SN74ALS575A , SN74ALS576B , SN74ALS577A , SN74ALS580B , SN74ALS666 , SN74ALS667 , SN74ALS74A , SN74ALS841 , SN74ALS843 , SN74ALS873B , SN74ALS874B , SN74ALS990 , SN74ALS992 , SN74ALS996 , SN74ALVCH162260 , SN74ALVCH162373 , SN74ALVCH162374 , SN74ALVCH16260 , SN74ALVCH162721 , SN74ALVCH162841 , SN74ALVCH16373 , SN74ALVCH16374 , SN74ALVCH16721 , SN74ALVCH16820 , SN74ALVCH16821 , SN74ALVCH16823 , SN74ALVCH16841 , SN74ALVCH373 , SN74ALVCH374 , SN74AS109A , SN74AS174 , SN74AS175B , SN74AS194 , SN74AS373 , SN74AS374 , SN74AS573A , SN74AS574 , SN74AS576 , SN74AS74A , SN74AS874 , SN74AUC16373 , SN74AUC16374 , SN74AUC1G74 , SN74AUC1G79 , SN74AUC1G80 , SN74AUC2G79 , SN74AUC2G80 , SN74AUC74 , SN74AUCH16374 , SN74AUP1G74 , SN74AUP1G79 , SN74AUP1G80 , SN74AUP2G79 , SN74AUP2G80 , SN74AVC16373 , SN74AVC16374 , SN74AVC16722 , SN74BCT374 , SN74BCT573 , SN74BCT574 , SN74F109 , SN74F112 , SN74F174A , SN74F175 , SN74F299 , SN74F373 , SN74F374 , SN74F377A , SN74F573 , SN74F574 , SN74F74 , SN74HC109 , SN74HC112 , SN74HC164 , SN74HC165 , SN74HC165-EP , SN74HC165-Q1 , SN74HC166 , SN74HC166A-EP , SN74HC166A-Q1 , SN74HC174 , SN74HC175 , SN74HC259 , SN74HC273 , SN74HC273-Q1 , SN74HC373 , SN74HC374 , SN74HC377 , SN74HC563 , SN74HC573A , SN74HC573A-Q1 , SN74HC574 , SN74HC594 , SN74HC595 , SN74HC595-EP , SN74HC74 , SN74HC74-EP , SN74HC74-Q1 , SN74HCT273 , SN74HCT373 , SN74HCT374 , SN74HCT377 , SN74HCT573 , SN74HCT574 , SN74HCT74 , SN74LS107A , SN74LS109A , SN74LS112A , SN74LS164 , SN74LS165A , SN74LS166A , SN74LS173A , SN74LS174 , SN74LS175 , SN74LS194A , SN74LS259B , SN74LS273 , SN74LS279A , SN74LS299 , SN74LS373 , SN74LS374 , SN74LS375 , SN74LS377 , SN74LS378 , SN74LS594 , SN74LS595 , SN74LS597 , SN74LS598 , SN74LS670 , SN74LS673 , SN74LS674 , SN74LS73A , SN74LS74A , SN74LS75 , SN74LV164A , SN74LV165A , SN74LV165A-EP , SN74LV165A-Q1 , SN74LV166A , SN74LV174A , SN74LV175A , SN74LV273A , SN74LV373A , SN74LV373A-Q1 , SN74LV373AT , SN74LV374A , SN74LV374A-EP , SN74LV374A-Q1 , SN74LV374AT , SN74LV573A , SN74LV573AT , SN74LV574A , SN74LV594A , SN74LV595A , SN74LV595A-EP , SN74LV595A-Q1 , SN74LV74A , SN74LV74A-EP , SN74LV74A-Q1 , SN74LV8153 , SN74LV8153-Q1 , SN74LVC112A , SN74LVC16373 , SN74LVC16373A , SN74LVC16373A-EP , SN74LVC16374 , SN74LVC16374A , SN74LVC1G175 , SN74LVC1G175-EP , SN74LVC1G373 , SN74LVC1G374 , SN74LVC1G374-Q1 , SN74LVC1G74 , SN74LVC1G79 , SN74LVC1G79-EP , SN74LVC1G80 , SN74LVC2G74 , SN74LVC2G74-EP , SN74LVC2G74-Q1 , SN74LVC2G79 , SN74LVC2G80 , SN74LVC373A , SN74LVC373A-EP , SN74LVC374A , SN74LVC374A-EP , SN74LVC374A-Q1 , SN74LVC573A , SN74LVC573A-EP , SN74LVC573A-Q1 , SN74LVC574A , SN74LVC574A-EP , SN74LVC574A-Q1 , SN74LVC74A , SN74LVC74A-EP , SN74LVC74A-Q1 , SN74LVC821A , SN74LVC823A , SN74LVC841A , SN74LVCH16373A , SN74LVCH16374A , SN74LVCH32373A , SN74LVTH162373 , SN74LVTH162373-EP , SN74LVTH162374 , SN74LVTH16373 , SN74LVTH16373-EP , SN74LVTH16374 , SN74LVTH16374-EP , SN74LVTH273 , SN74LVTH273-EP , SN74LVTH373 , SN74LVTH373-EP , SN74LVTH374 , SN74LVTH374-EP , SN74LVTH573 , SN74LVTH573-EP , SN74LVTH574 , SN74LVTH574-EP , SN74S112A , SN74S175 , SN74S374 , SN74S74

PRODMIX  

  1.   Power-Up Behavior of Clocked Devices
  2. 1Unknown States at Power-Up
  3. 2Solutions to Unknown States at Power-Up
    1. 2.1 Use a Device with Clear or Preset Pins
    2. 2.2 Delay the Clock Edge with an RC Circuit and Schmitt Trigger Buffer
    3. 2.3 Wait Until VCC Has Ramped
  4. 3Trademarks
  5. 4Revision History

Power-Up Behavior of Clocked Devices

Some logic devices, such as flip-flops and shift registers, require the use of a clock input, typically designated CLK or CP. The state of the outputs of these devices change once an appropriate clock edge has occurred. Device datasheets specify whether the action occurs on a positive or negative edge of the clock. However, the behavior of a device upon power-up is not always specified before a valid clock edge has occurred.