原创 逻辑电平兼容

输入参数

CMOS：输入高电平UIH min =（0.65～0.7）×5V，输入低电平UIL max  =（0.3～0.35）×5V

LVCMOS：


按照正常的情况

LVCMOS输出=>CMOS输入，电平可能太低，导致高电平无法识别。

CMOS输出=>LVCMOS输入，电平可能太高，导致IO口钳位。

目前网上有很多解决电平的方案，仔细分析一下，并对比优缺点和使用范围。

Device Families:
TTL (74xx)  True TTL  
74L         Low power 
74S         Schottky  
74H         High speed
74LS        Low power - Schottky              
74AS        Advanced - Schottky       
74ALS       Advanced - Low power - Schottky              
74F(AST)    Fast - (Advanced - Schottky)      
74C         CMOS...................check Vcc levels   
74HC (U)    High speed - CMOS (Unbuffered output)      
74HCT       High speed - CMOS - TTL inputs          
74AHC       Advanced - High speed - CMOS              
74AHCT      Advanced - High speed - CMOS - TTL inputs 
74FCT (-A)  Fast - CMOS - TTL inputs (speed variations)
74FCT (-T, -AT) Fast - CMOS - TTL inputs (speed variations)
74AC        Advanced - CMOS                           
74ACT       Advanced - CMOS - TTL inputs             
74FACT      AC, ACT (Q) series                    
74ACQ       Advanced - CMOS - Quiet outputs               
74ACTQ      Advanced - CMOS - TTL inputs - Quiet outputs

Bus Driver Families
74ABT       Advanced - BiCMOS - Technology               
74ABTE      ABT - Enhanced Transceiver Logic              
74ABTH      Advanced - BiCMOS - Technology - bus Hold 
74BCT       BiCMOS - TTL inputs                      
74BTL       Backplane - Transceiver - Logic           
74GTL       Gunning - Transceiver - Logic             
74GTLP      GTL Plus                              

Low Voltage Families
74ALB       Advanced - Low Voltage - BiCMOS               
74LV (U)    Low - Voltage (Unbuffered output)         
74LVC (R)   LV - CMOS (damping Resistor)(Unbuffered output)
74LVCH          Low - Voltage - CMOS - bus Hold               
74ALVC          Advanced - Low - Voltage - CMOS               
74LVT (R) (U)   LV - TTL  (damping Resistor(Unbuffered output)
74LVTZ          Low - Voltage - TTL - High Impedance power-up 
74ALVC (R)  ALV - CMOS (bus Hold) (damping Resistor)  
74ALVCH         Advanced - Low - Voltage - CMOS - bus Hold
74LCX           LV - CMOS (operates with 3v & 5v supplies)
74VCX           LV - CMOS (operates with 1.8v & 3.6v supplies

4000            True CMOS (non-TTL levels)            

ECL Device Families:
MEC I           8nS*              
MEC II          2nS*                  
MEC III         (16XX)  1nS*  .......* = Rise & Fall Times
101xx           100 series 10K ECL, 3.5nS*            
102xx           200 series 10K ECL, 2.5nS*            
108xx           800 series 10K ECL, voltage compensated, 3.5nS*
10Hxxx          10K - High speed, voltage compensated, 1.8nS*
10Exxx          10K - ECLinPS, voltage compensated, 800pS*
100xxx          100K, temperature compensated                 
100Hxxx         100K - High speed, temperature compensated
100Exxx         100K - ECLinPS, temp, voltage comp., 800pS*