Input Termination For Delay Locked Loop Feedback With Impedance Matching
First Claim
1. A reference output circuit comprising:
- a control circuit configured to provide an output clock signal for driving one or more output signals; and
a terminated load module configured to switch between a pull-up configuration and a pull-down configuration in response to the output clock signal, wherein the terminated load module emulates terminated loads driven by the output signals.
3 Assignments
0 Petitions
Accused Products
Abstract
A reference output circuit for generating an output clock signal for driving signals off of an integrated circuit chip uses a switched terminated load in combination with an output buffer to generate a feedback clock signal, which is used, in combination with a reference input clock signal, to generate the output clock signal. The switched terminated load uses transistors having the same size as transistors in the output buffer. The switched terminated load draws the same DC current as the output buffer. As a result, the switched terminated load and the output buffer have the same electro-migration performance. Pull-up and pull-down MOS impedances of the switched terminated load are easily adjusted during switching periods of the switched terminated load. The design of the switched terminated load minimizes variations in the terminated load impedance due to MOS impedance variations.
-
Citations
18 Claims
-
1. A reference output circuit comprising:
-
a control circuit configured to provide an output clock signal for driving one or more output signals; and a terminated load module configured to switch between a pull-up configuration and a pull-down configuration in response to the output clock signal, wherein the terminated load module emulates terminated loads driven by the output signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
-
-
14. A method for driving signals off of an integrated circuit chip, the method comprising:
-
generating an output clock signal; driving one or more signals off of the integrated circuit chip to one or more corresponding terminated loads in response to the output clock signal; switching a terminated load circuit on the integrated circuit chip in response to the output clock signal, wherein the terminated load circuit emulates the terminated loads located off of the integrated circuit chip. - View Dependent Claims (15, 16, 17, 18)
-
Specification