ATF1508ASZ-20JC84 ATMEL Corporation, ATF1508ASZ-20JC84 Datasheet - Page 6

• Manufacturer Part Number: ATF1508ASZ-20JC84
• Description: High Performance E2 PLD
• Manufacturer: ATMEL Corporation

Figure 1. ATF1508AS Macrocell
Programmable Pin-Keeper Option
for Inputs and I/Os
The ATF1508AS offers the option of programming all input
and I/O pins so that “pin keeper” circuits can be utilized.
When any pin is driven high or low and then subsequently
left floating, it will stay at that previous high or low level.
This circuitry prevents unused input and I/O lines from
floating to intermediate voltage levels, which cause unnec-
essary power consumption and system noise. The keeper
circuits eliminate the need for external pull-up resistors and
eliminate their DC power consumption.
Input Diagram
6
ATF1508AS/Z
Speed/Power Management
The ATF1508AS has several built-in speed and power
management features. The ATF1508AS contains circuitry
that automatically puts the device into a low power stand-
by mode when no logic transitions are occurring. This not
only reduces power consumption during inactive periods,
but also provides a proportional power savings for most
applications running at system speeds below 5 - 10 MHz.
To further reduce power, each ATF1508AS macrocell has
a Reduced Power bit feature. This feature allows individual
macrocells to be configured for maximum power savings.
This feature may be selected as a design option.
I/O Diagram