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Browse Prior Art Database

MULTIPLE POWER SUPPLY BETA-SQUARED ESD CIRCUIT PROTECTION

IP.com Disclosure Number: IPCOM000007938D
Original Publication Date: 1996-Nov-01
Included in the Prior Art Database: 2002-May-07
Document File: 2 page(s) / 74K

Publishing Venue

Motorola

Related People

Bob Berger: AUTHOR

Abstract

In the next generations of new analog/digital high drive/fan-out circuits, multiple power supply buses have been required to reduce coupling noise or to provide for external power supply filters. This paper provides a means to reduce the impact of these multiple power supplies on the ESD performance of the device. The key element of the disclosure pro- vides what is called the ESD Power Rail. The ESD Power Rail (EPR) provides a common path for all power supply rails such as the analog, digital, and output (x) power supplies to the substrate. The fol- lowing diagram illustrates how a prior multiple power supply connection may have been done and how with this disclosure improves the circuit.

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MO7VROLA Technical Developments

MULTIPLE POWER SUPPLY BETA-SQUARED ESD CIRCUIT PROTECTION

by Bob Berger

In the next generations of new analog/digital high drive/fan-out circuits, multiple power supply

buses have been required to reduce coupling noise or to provide for external power supply filters. This paper provides a means to reduce the impact of these multiple power supplies on the ESD performance of the device. The key element of the disclosure pro- vides what is called the ESD Power Rail. The ESD

Power Rail (EPR) provides a common path for all power supply rails such as the analog, digital, and output (x) power supplies to the substrate. The fol- lowing diagram illustrates how a prior multiple power supply connection may have been done and how with this disclosure improves the circuit.

VCCI vcd WC3 WC4

vccl vcc2 vcc3 vcc4 EPR

we/substrate CONVENTIONAL

we/substrate DISCLOSED

  As the number of power supply rails vccx in the conventional circuit increases so does the complex- ity of the circuit. Conversely the disclosed approach remains relatively simple. From an AC coupling standpoint (of one power supply rail to the other) across the diodes both circuits are identical.

The distinct advantage of the disclosure is hid- den within the diodes of the above circuit. In the

simple diagram below it can be seen that the diode of each vcc(x) and the first diode of the EPR form a Darlington pair of PNP transistors. Even without good PNP's the Darlington effect would con...