74HCT238

The 74HCT238 is designed as high-speed si-gate CMOS devices and are pin compatible with low power schottky TTL (LSTTL). It is specified in compliance with JEDEC standard no. 7A. It accepts three binary weighted address inputs (A0, A1, A2) and when enabled, provide 8 mutually exclusive active high outputs (Y0 to Y7).

The six features of the 74HCT238. The first one is demultiplexing capability. The second one is multiple input enable for easy expansion. The third one is it would be ideal for memory chip select decoding. The fourth one is active high mutually exclusive outputs. The fifth one is its output capability would be standard. The sixth one is its ICC category would be MSI. That are all the main features.

Some important AC characteristics and specifications of the 74HCT238 have been concluded into several points as follow.For Tamb=25°C the first one is about its propagation delay An to Yn which would be typ 47ns and max 150ns at Vcc=2.0V and would be typ 17ns and max 30ns at Vcc=4.5V and would be typ 14ns and max 26ns at Vcc=6.0V. The second one is about its propagation delay E3 to Yn which would be typ 52ns and max 160ns at Vcc=2.0V and typ 19ns and max 32ns at Vcc=4.5V and would be typ 15ns and max 27ns at Vcc=6.0V. The third one is about its output transition time which would be typ 19ns and max 75ns at Vcc=2.0V and typ 7ns and max 15ns at Vcc=4.5V and would be typ 6ns and max 13ns at Vcc=6.0V.

Also for the Tamb range of the 74HCT238 -40 to +125°C the first one is about its propagation delay An to Yn which would be max 225ns at Vcc=2.0V and would be max 45ns at Vcc=4.5V and would be max 38ns at Vcc=6.0V. The second one is about its propagation delay LE to Yn which would be max 240ns at Vcc=2.0V and max 48ns at Vcc=4.5V and would be max 41ns at Vcc=6.0V. The third one is about its output transition time which would be max 110ns at Vcc=2.0V and max 22ns at Vcc=4.5V and would be max 19ns at Vcc=6.0V. And so on. For more information please contact us.

The 74HCT238 is high-speed Si-gate CMOS devices and are pin compatible with low power Schottky TTL (LSTTL). They are specified in compliance with JEDEC standard no. 7A.

The 74HCT238 decoders accept three binary weighted address inputs (A0, A1, A2) and when enabled,provide 8 mutually exclusive active HIGH outputs (Y₀ to Y₇).

The "238" features of the 74HC/HCT238  three enable inputs: two active LOW (E₁ and E₂) and one active HIGH (E₃). Every output will be LOW unless E₁ and E₂ are LOW and E3 is HIGH.

This multiple enable function of the 74HC/HCT238  allows easy parallel expansion of the "238" to a 1-of-32 (5 lines to 32 lines) decoder with just four "238" ICs and one inverter.

The "238" 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. Unused enable inputs must be permanently tied to their appropriate active HIGH or LOW state.

The "238" is identical to the "138" but has non-inverting outputs.