74HCLSHCTF系列芯片的区别(国外英文资料).doc

74HCLSHCTF系列芯片的区别(国外英文资料) 74HC/LS/HCT/F series chip difference The 1 and LS are low power Schottky, and the HC is a high-speed COMS. LS is slightly faster than HC. The HCT inputs and outputs are compatible with the LS, but the power dissipation is low; the F is a high speed Schottky circuit; 2, LS is the TTL level, and the HC is the COMS level. 3, LS input open to high, HC input is not allowed to open the circuit, HC generally require a pull-down resistor to determine the level of input invalid. LS didnt ask for it 4, LS output drop-down, strong pull weak, HC pull down the same. 5, work voltage is different, LS can only use 5V, and HC is generally 2V to 6V; 6, the level is different. LS is the TTL level, its low and high levels are 0.8 and V2.4, respectively, and the CMOS is 0.3V and 3.6V at the operating voltage of 5V, so the CMOS can drive TTL, But the reverse is no good 7, driving ability is different, LS general high level driving ability is 5mA, low level is 20mA; and CMOS level is 5mA; 8, CMOS device antistatic ability is poor, easy to latch problems, so the CMOS input pin can not directly connect the power supply. The 74 series of integrated circuits can be broadly divided into 6 major categories: 74 * * (standard type); .74LS * * (low power Schottky); .74S * * (Schottky); .74ALS x (advanced low power Schottky barrier); .74AS * * (advanced schottky barrier); .74F * x (high speed). In recent years, the 74 series of high-speed CMOS circuits have emerged. The series can be divided into 3 major categories: HC is the COMS operating level; The HCT is the TTL operating level and can be used interchangeably with the 74LS family; .HCU is CMOS in the buffer circuit. The 9 74 series products have the same logic function and pin arrangement as long as the label is the same. According to the different conditions and requirements, you can choose different types of 74 series products, such as the circuit The power supply voltage is 3V, and 74HC series products should be sel