1. General description
The 74LVC138A decodes three binary weighted address inputs (A0, A1 and A2) to eight mutually
exclusive outputs (Y0 to Y7). The 74LVC138A features three enable inputs (E1, E2 and E3). Every
output will be HIGH unless E1 and E2 are LOW and E3 is HIGH. This multiple enable function
allows easy parallel expansion of the 74LVC138A to a 1-of-32 (5 to 32 lines) decoder with just four
74LVC138A ICs and one inverter. The 74LVC138A can be used as an eight output demultiplexer
by using one of the active LOW enable inputs as the data input and the remaining enable inputs as
strobes. Inputs can be driven from either 3.3 V or 5 V devices. This feature allows the use of these
devices as translators in mixed 3.3 V and 5 V environments.
Schmitt-trigger action at all inputs makes the circuit tolerant of slower input rise and fall times.
2. Features and benefits
• Overvoltage tolerant inputs to 5.5 V
• Wide supply voltage range from 1.2 V to 3.6 V
• CMOS low power consumption
• Direct interface with TTL levels
• Demultiplexing capability
• Multiple input enable for easy expansion
• Ideal for memory chip select decoding
• Mutually exclusive outputs
• Output drive capability 50 Ω transmission lines at 125 °C
• Complies with JEDEC standard:
• JESD8-7A (1.65 V to 1.95 V)
• JESD8-5A (2.3 V to 2.7 V)
• JESD8-C/JESD36 (2.7 V to 3.6 V)
• ESD protection:
• HBM JESD22-A114F exceeds 2000 V
• MM JESD22-A115-B exceeds 200 V
• CDM JESD22-C101E exceeds 1000 V
• Specified from -40 °C to +85 °C and from -40 °C to +125 °C