How do I convert a 12-bit integer to a hexadecimal string in C#?

2748.ToString("X")

2748.ToString("X")

char hexCharacters[17] = "0123456789ABCDEF";
void toHex(char * outputString, long input)
{
   outputString[0] = hexCharacters[(input >> 8) & 0x0F];
   outputString[1] = hexCharacters[(input >> 4) & 0x0F];
   outputString[2] = hexCharacters[input & 0x0F];
}

i.ToString("X3")

(i % 0x1000).ToString("X3")