The SN74GTL3004 provides for a selectable GTL Voltage Reference (GTL VREF). The value of the GTL VREF can be adjusted using S0 and S1 select pins. The S0 and S1 pins contain glitch-suppression circuitry for excellent noise immunity. When left floating, the S0 and S1 control input pins have 100-kµ pullups that set the GTL VREF default value to the 0.67 × VTT ratio (S0 = 1 and S1 =1).