LED Message Sign HT16D595 Characteristics Operating Voltage : 4.5V ~ 5.5V Pin-to-pin compatible with 74HC595 8 constant current output channels Insensitive to load (LED Vf) variations Insensitive to line (VCC) variations Constant output current : 48mA No current setting resistor or current limit resistor Output current accuracy : Between channels : ±1.5% (typ.) Between chips : ±3% (typ.) 25MHz clock frequency LEDs Decoder Controller HT16D595 … 74HC595 HT16D595 74HC595 LEDs Decoder Note: The 74HC595 current is dependent upon load variations. The HT16D595 current is independent of load variations. Operating Procedure Display Modes : Text Message Load Change + IC Type Load Change Power Plug Plug in power Select Load Change + IC Type, Orange, and high brightness enables differences to be easily seen Colour selection : Green, Red, Orange Brightness Control : High, Mid, Low Application Circuit Comparison 74HC595 HT16D595 General Constant Current IC Poor Good Good Voltage Endurance 7V 17V 17V Blue LED Driving No Yes Yes 595 Compatible Yes Yes No Maybe No Yes No No Yes High Low Low -- No Yes Current Stability Current Set Resistor Development Fee Repair Rate Risk