74LVC138AD

The 74LVC138AD is a 3-to-8 line decoder/demultiplexer in the 74LVC family. It has inputs A, B, C and three enable pins: G1 (active high) and G2A, G2B (active low). When enabled (G1 = 1, G2A = 0, G2B = 0), exactly one of the eight outputs Y0–Y7 goes low according to the binary value of A, B, C (Y0 corresponds to 000, Y1 to 001, …, Y7 to 111). All other outputs stay high. If disabled, all outputs are high.
Key specs (typical): CMOS logic with low power consumption; operating voltage 1.65–3.6 V; inputs CMOS-compatible. Outputs are active-low. Package options vary (including the AD variant), so check the datasheet for pinout and package details.
Common uses: address decoding, demultiplexing a bus, and routing signals in digital circuits. For exact electrical characteristics and packaging, consult the specific TI datasheet for the 74LVC138AD variant.

74LVC138AD is a 3-to-8 decoder/demultiplexer with eight active-low outputs and enables G1 (high) and G2A/G2B (low).
Equivalents (drop-ins in the same function):
- TI SN74LVC138ADG4
- Nexperia 74LVC138A
- ON Semiconductor 74LVC138A
- 74HC138 / 74HCT138 (for compatible voltage ranges)
Note: check supply voltage (1.65–5.5 V) and enable polarity for true compatibility.

- 3-to-8 line decoder/demultiplexer
- 8 active-low outputs (Y0–Y7)
- 3 enable inputs: G1 (active-high), G2A and G2B (both active-low)
- A, B, C inputs select which Y is driven low when enabled
- Vcc = 1.65 V to 3.6 V (LVC family); CMOS inputs with TTL-compatible thresholds
- Fast CMOS with low static power
- Packaged in 16-pin devices (AD suffix indicates the D/SOIC package)
- Pin-compatible with 74x138 family for easy integration
- Common applications: address decoding, data routing/demuxing in digital systems

- Pin count: 16 pins (DIP/SOIC variants exist).
- Function: 3-to-8 decoder/demultiplexer. Decodes 3 select inputs (A, B, C) to eight active-low outputs Y0–Y7. It has three enables: G1 (active high) and G2A, G2B (both active low). When enabled, exactly one Y0–Y7 is driven low corresponding to the ABC value; all outputs are high when not enabled.

- Manufacturer: Nexperia.
- What kind of company: A global semiconductor company that designs and manufactures standard logic ICs and discrete semiconductor components (e.g., logic gates, MOSFETs).

Common application areas for the 74LVC138AD:
- 3-to-8 address decoding and chip-select generation for memories and peripherals in microcontroller/microprocessor systems
- Demultiplexing a control signal to enable one of eight devices on a bus
- Glue logic in FPGA/ASIC designs (simple decoder/enabler blocks)
- Driving or enabling LED/matrix displays and other load devices (outputs are active-low)
- Level-compatible interfacing between different logic families in low-voltage systems (Vcc typically 1.65–3.6 V)

It’s a 16-pin surface-mount device, typically in an SOIC-16 (0.300" wide) package. Some vendors also offer other 16-pin options like TSSOP-16—check the datasheet for the exact variant.