CD74HC4051: Regarding abs of switch diode current

Daisuke Higa

Genius 4350 points

Part Number: CD74HC4051

Hi support team

Could you please tell me what the switch diode current IOK is?

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DC Switch Diode Current, IOK

For VI < VEE -0.5V or VI > VCC + 0.5V . . . . . . . . . . . . . . . . .± 20mA

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Best regards,

Higa

over 4 years ago

0 Clemens Ladisch over 4 years ago

Guru 317260 points

This is the current through the ESD protection diodes (when the input voltages go beyond the allowed range). See sections 4.4.6 and 4.4.7 of the Understanding and Interpreting Standard-Logic Data Sheets application report.

+1 Parker Dodson over 4 years ago

TI__Guru 52352 points

Hi Higa,

Clemens is correct. This is the limit through the ESD protection diodes that are found on the analog I/O pins (Pins labeled "A" on the 4051). If an overvoltage or undervoltage event occurs w.r.t. ground on an analog pin the ESD diodes will clamp to VDD or GND respectively. However these diodes have a current limit of +/- 20mA and may damage the device if this value is exceeded.

If you have any other questions please don't hesitate to reach out!

Best,

Parker Dodson

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CD74HC4051: Regarding abs of switch diode current