Browse Prior Art Database

Programming Resistor in Off Chip Driver in Large Scale Integration

IP.com Disclosure Number: IPCOM000120269D
Original Publication Date: 1997-Nov-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Kanzaki, E: AUTHOR [+3]

Abstract

Disclosed is a device for an Off Chip Driver (OCD) which has the variable resistance source terminated. Here, variable resistance is programmed according to output load after the fabrication process of Large Scale Integration (LSI).

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Programming Resistor in Off Chip Driver in Large Scale Integration

      Disclosed is a device for an Off Chip Driver (OCD) which has
the variable resistance source terminated.  Here, variable resistance
is programmed according to output load after the fabrication process
of Large Scale Integration (LSI).

      The Figure shows an example of the device.  Generally, OCD
consists of a large Field Effect Transistor (FET), output control
circuit pad.  This device has a special circuit between the output of
the large  FET and pad.  This special circuit consists of one
resistor and one transfer gate for a switch which is controlled by an
internal or external  signal in the LSI.  One resistor is parallel to
the transfer gate for the switch.  In the Figure, T1 (1) is a large
P-FET (P type FET), T2 (2)  is a large N-FET (N type FET), R1 (3) is
a resistance (Polysilicon Resistance), Transfer Gate (TG) (4) is a
transfer gate for the switch.  When the control signal (5) is
activated, TG is on and R1 is short.  The output of OCD which
consists of T1 (1) and T2 (2) is connected to the pad.  On the other
hand, when the control signal (5) is not activated, TG is off.  The
output of OCD which consists of T1 (1)  and T2 (2) connected to the
pad via P1.  When the output load of LSI is  inductive, Elector
Magnetic Interference (EMI) appears.  This circuit reduces EMI
according to the value of the output load when it is actually  used.

      This example shows th...