atf16v8cz ATMEL Corporation, atf16v8cz Datasheet - Page 8

• Manufacturer Part Number: atf16v8cz
• Description: Highperformance Ee Pld Atf16v8cz
• Manufacturer: ATMEL Corporation

6. Input and I/O Pin-keeper Circuits
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ATF16V8CZ
The ATF16V8CZ contains internal input and I/O pin-keeper circuits. These circuits allow each
ATF16V8CZ pin to hold its previous value even when it is not being driven by an external source
or by the device’s output buffer. This helps insure that all logic array inputs are at known, valid
logic levels. This reduces system power by preventing pins from floating to indeterminate levels.
By using pin-keeper circuits rather than pull-up resistors, there is no DC current required to hold
the pins in either logic state (high or low).
These pin-keeper circuits are implemented as weak feedback inverters, as shown in the Input
Diagram below. These keeper circuits can easily be overdriven by standard TTL- or CMOS-com-
patible drivers. The typical overdrive current required is 40 µA.
Figure 6-1.
Figure 6-2.
Input Diagram
I/O Diagram
0453H–PLD–7/05