Browse Prior Art Database

ECL to TTL Translate Circuit for Laserable PLA

IP.com Disclosure Number: IPCOM000048329D
Original Publication Date: 1982-Jan-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Flaker, RC: AUTHOR

Abstract

This article discloses a programmable ECL (emitter coupled logic) to TTL (transistor transistor logic) translation circuit which can be pretested before programming. Shown is an ECL circuit comprising transistors 1 through 11 and diodes D1 through D6. Latch offset signals M and M/-/ are received from a latch circuit (not shown) and translated through buffer transistors 2 and 3 and diodes D1 and D2 to the bases of transistors 5 and 6. A single composite transistor could be substituted for transistors 5 and 7 and the diode D4. Similarly, a simple composite transistor could be substituted for transistors 6 and 8 and the diode D3. In any event, these devices together with the resistors R1 and R2 form a current switch that drives the current mirror comprised of transistor 11 and diode D5.

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ECL to TTL Translate Circuit for Laserable PLA

This article discloses a programmable ECL (emitter coupled logic) to TTL (transistor transistor logic) translation circuit which can be pretested before programming. Shown is an ECL circuit comprising transistors 1 through 11 and diodes D1 through D6. Latch offset signals M and M/-/ are received from a latch circuit (not shown) and translated through buffer transistors 2 and 3 and diodes D1 and D2 to the bases of transistors 5 and 6. A single composite transistor could be substituted for transistors 5 and 7 and the diode D4. Similarly, a simple composite transistor could be substituted for transistors 6 and 8 and the diode D3. In any event, these devices together with the resistors R1 and R2 form a current switch that drives the current mirror comprised of transistor 11 and diode D5. The collector of the transistor 11 is coupled to a transistor logic off-chip driver (OCD) circuit (not shown). When the node at the collector of transistor 10,
i.e., the base of transistor 6, is more positive than the node at the collector of a transistor 9 and the base of transistor 5, transistor 11 is caused to turn on, pulling down the output line and shutting off the attached off-chip driver. When the other node at the collector of transistor 9 is more positive, then current is supplied to the output line and off-chip driver through diodes D3 and transistor 8, causing the off-chip driver to be turned on.

By providing incomplete input...