Motorola Corporation

C Christopher Hanke, Iii

Ray D Sundstrom

Barry B Heim

Michael W Hodel

Tzu-Hui P Hu

William F Johnstone

Todd Pearson

A circuit and method for providing phase synchronization between an ECL output signal and a TTL or CMOS output signal has been provided. The circuit includes phase locked loops (20, 24) to make the difference of delays through an ECL-TTL/CMOS translation path with that of a straight ECL path irrelevant. As a result, in order to achieve phase synchronization between an ECL signal and a TTL/CMOS signal, one only needs to match the propagation delay of a delay component (22) to that of a TTL/CMOS-ECL translator (26) as opposed to a delay component and an ECL-TTL/CMOS translator.

Circuit and method for providing phase synchronization of ECL and

A delay matching circuit has a first node (48), a second node (50), a first loading circuit (54, 56), a second loading circuit (58, 60), a third loading circuit (64) and a buffer circuit (62). The first loading circuit couples a first logic state to the first node responsive to a first state of a control signal. The second loading circuit couples a second logic state to the first node responsive to a second state of the control signal. The buffer circuit electrically couples the first and second nodes. The first loading circuit, second loading circuit and buffer circuit are characterized by a first, a second and a third predetermined electrical impedance, respectively. The third loading circuit is coupled to the second node and is characterized by a fourth predetermined electrical impedance. The disclosed delay matching circuit propagates a clock signal input with a delay equal to the Clock-to-Q delay associated with a flip-flop constructed with similar circuit elements. The disclosed delay matching circuit is useful in circuits, such as phase locked loops, where the simultaneous propagation of two signals is critical.

Delay matching circuit

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Austin, TX, United States of America

C Christopher Hanke, Iii