The 74LCX138 is a low voltage 1-of-8 decoder/demultiplexer with 5V tolerant inputs. This device is ideally suited for high-speed memory chip select address decoding. The multiple input enables allow parallel expansion to a 1-of-24 decoder using just three LCX138 devices or a 1-of-32 decoder using four LCX138 devices and one inverter. The 74LCX138 is fabricated with advanced CMOS technology to achieve high speed operation while maintaining CMOS low power dissipation.
The 74LCX138 is a high‑speed 1‑of‑8 decoder/demultiplexer designed for memory chip‑select address decoding. It accepts three binary weighted inputs and provides eight mutually exclusive active‑LOW outputs, with three enable inputs (two active‑LOW, one active‑HIGH). The device is offered in multiple packages, including SOIC, SOP, TSSOP and lead‑less DQFN.
Key electrical characteristics include a 2.3 V to 3.6 V input voltage range, up to ±24 mA output drive at VCC = 3.0 V, propagation delays as low as 1.5 ns (typical) and a quiescent supply current of about 10 µA. The part operates from –40 °C to +85 °C and complies with a life‑support policy that restricts use in critical medical devices.
| Input voltage range | 2.3 V to 3.6 V |
|---|---|
| Output drive current | ±24 mA (VCC = 3.0 V) |
| Operating temperature range | -40 °C to +85 °C |
The device can source or sink up to ±24 mA per output when VCC is 3.0 V.
The inputs are tolerant to 5 V and operate correctly from 2.3 V to 3.6 V.
The device is specified for a free‑air operating temperature from –40 °C to +85 °C.