Browse Prior Art Database

MOSFET Line Receiver

IP.com Disclosure Number: IPCOM000080567D
Original Publication Date: 1974-Jan-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Lowry, PO: AUTHOR [+2]

Abstract

This metal-oxide semiconductor field-effect transistor (MOSFET) line receiver includes an on-chip capacitor, which cooperates with an external resistor to eliminate noise transitions induced into an input line.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

MOSFET Line Receiver

This metal-oxide semiconductor field-effect transistor (MOSFET) line receiver includes an on-chip capacitor, which cooperates with an external resistor to eliminate noise transitions induced into an input line.

The MOSFET line receiver is constructed in a way to form a capacitor C1 from the drain to the gate of FET 1, with FET 3 acting as a pull-up resistor to VDD thereby forming a "Miller" network. This arrangement increases the charge and discharge time of C1 and, therefore, provides a larger delay from input to output. Due to the "Miller" effect, the voltage on the drain of FET 1 has a very slow rise and fall time as compared with typical FET transitions. To increase the rise and fall time of the output waveform, a high-gain buffer stage, made up of FET 2 and FET 4 is provided. With FET 2 at high gain and FET 4 providing the pull-up to VDD, the output will switch when the voltage on the gate of FET 2 is at or near the threshold thereof. External resistor R1 provides a pull-up to V1. This voltage can be either VLG or VDD. External resistor R2 combined with the resistance of FET 5 provides the charging path to charge C1.

Fig. 2 depicts waveform transitions at different nodes in the circuit. If noise is coupled into the cable, it must have an energy profile equal to or greater than V1 over the time t2-t1 or V1 over the time t4-t3, to cause a transition on the output waveform.

1

Page 2 of 2

2

[This page contains 3 pictures or other non-text ob...