CD4011BM - Design considerations for unconnected gate

Dimitrios Alexandrou52

Part Number: CD4011BM

Question type: Development and troubleshooting

Support topic: /Reference designs/Help finding technical applications collateral/

Description of the problem: In my design I am using CD4011BM as a switch and I am using three out of four gates. The fourth gate is unconnected but I noticed that there is current consumption when the switch is off. Is there a problem on not connecting at all the fourth gate. Do I have to putt them low or high any of the pins.

Thanks in Advance
Dimitris

over 8 years ago

0 Adam Torma over 8 years ago

TI__Mastermind 45575 points

Dimitios,

Thank you for your question. These NAND gate devices are supported in our logic forum. I will move your post to that forum where someone will assist you soon.

Adam

0 ShreyasRao over 8 years ago in reply to Adam Torma

TI__Guru 62180 points

Hi Dimitrios ,

please refer to the logic FAQs which talk about the floating inputs .
The logic inputs needs to be connected to one of the rails either Vcc or gnd. This is to avoid picking up random voltages and float to a midpoint of Vcc which can cause a large through current to flow through and potentially damage the device.

e2e.ti.com/.../2945.floating-the-inputs-of-logic-devices

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CD4011BM - Design considerations for unconnected gate