onsemi (Ansemi)

TSSOP-16

Tube

96

The VHCT138A is an advanced high-speed CMOS 3-8 decoder fabricated on a silicon-gate CMOS process. It achieves high operating speeds similar to equivalent bipolar Schottky TTLs while maintaining CMOS low power consumption. When the device is enabled, 3 binary select inputs (A0, A1, and A2) determine which output (O#0-O#7) will go low. When enable input E3 is held low, or E#1 or E#2 is held high, the decode function is disabled and all outputs go high. The E3, E#1, and E#2 inputs are used to simplify cascading connections and serve as address decoders for the memory system. A protection circuit ensures that 0V to 7V is applied to the input pin regardless of the supply voltage at VCC = 0V and the output pin. These circuits prevent device damage due to mismatched supply and input/output voltages. The device can be used as an interface between 3-V systems and 5-V systems as well as two power systems, such as battery backup.