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Altera Corporation
MAX 7000B Programmable Logic Device Family Data Sheet
Preliminary Information
Open-Drain Output Option
MAX 7000B devices provide an optional open-drain (equivalent to
open-collector) output for each I/ O pin. This open-drain output enables
the device to provide system-level control signals (e.g., interrupt and
write enable signals) that can be asserted by any of several devices. It can
also provide an additional wired-
OR
plane.
Programmable Ground Pins
Each unused I/ O pin on MAX 7000B devices may be used as an additional
ground pin. This programmable ground feature does not require the use
of the associated macrocell; therefore, the buried macrocell is still
available for user logic.
Slew-Rate Control
The output buffer for each MAX 7000B I/ O pin has an adjustable output
slew rate that can be configured for low-noise or high-speed performance.
A faster slew rate provides high-speed transitions for high-performance
systems. However, these fast transitions may introduce noise transients
into the system. A slow slew rate reduces system noise, but adds a
nominal delay of 4 to 5 ns. When the configuration cell is turned off, the
slew rate is set for low-noise performance. Each I/ O pin has an individual
EEPROM bit that controls the slew rate, allowing designers to specify the
slew rate on a pin-by-pin basis. The slew rate control affects both the
rising and falling edges of the output signal.
Advanced I/O Standard Support
The MAX 7000B I/ O pins support the following I/ O standards: LVTTL,
LVCMOS, 1.8-V I/ O, 2.5-V I/ O, GTL+, SSTL-3 Class I and II, and SSTL-2
Class I and II.
Table 8. MAX 7000B MultiVolt I/O Support
V
CCIO
(V)
Input Signal (V)
Output Signal (V)
1.8
v
v
v
2.5
v
v
v
3.3
v
v
v
5.0
1.8
v
2.5
3.3
5.0
1.8
2.5
v
3.3
v
v