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AR# 7637

XPLA1 - What are CoolRunner startup current or high current demands?

Description

Keywords: XPLA, starting, LDD, LCC, low, impedance, power, supply

The XPLA1 CPLD does not appear to start up on a low current (high impedance) supply. Are there any times that the CPLD requires a higher level of current?

解决方案

There are two distinct times that XPLA1 devices require a higher amount of current to start.

During power-up, the CPLD monitors the level of VDD. At approximately 2.4V, the device recognizes
that it has enough voltage to sustain operation, and it enters a configuration and reset mode. This
requires about 50mA to 100mA for a short period of time (typically 20 microseconds or so). If this initial power is
not available for startup, the device will not configure properly and will draw a higher amount of
current for a sustained period of time. The part might also self-heat and resemble a "latched" part.

The CPLD also requires a larger amount of current (10mA to 100mA) during ISP operations. Program
and Verify require a significant amount of current to correctly perform their operations.
AR# 7637
创建日期 08/21/2007
Last Updated 07/28/2009
状态 Archive
Type 综合文章