Some early versions of Spartan-II parts and documentation include a power-down pin and a power-down status pin; the software also refers to "power down." However, the current documentation does not mention them. What is the status of these pins?
The power-down feature has been removed from all Spartan-II production devices. For new designs that require low power consumption, the CoolRunner XPLA3 family (a CPLD macrocell-based solution) is a good alternative solution.
Also a very good solution is the Spartan-3A device, which has a suspend mode that can achieve 40% lower quiescent current.
A number of the ES (engineering sample) devices that had the power-down feature enabled experienced configuration problems when the power-down pin was undriven, and was thus left to be pulled High with the internal (weak) pull-up. To prevent such problems, the power-down pin on the following devices should be tied High:
Pull-up requirements for Spartan-II devices:
- XC2S15-5CES (all packages)
- XC2S30-5CES (all packages)
- XC2S150-5C with date code 0045 or earlier (all packages)
For the devices listed above, the power-down pin should be tied to VCCINT on the PCB. VCCO can also be used as long as it does not exceed 3.3V and ramps up just as fast, if not faster than VCCINT. A pull-up resistor can be used if desired; the resistance value must be 10 Kohms or less.
For all other Spartan-II devices, the pins originally designated as power-down and status (/PWDN and STATUS, respectively) may be left floating, as they are not connected internally. If there is any doubt, tie the pins High.
The pins that were originally /PWDN, STATUS are:
* VQ100 (XC2S15/30): P28, P29
* TQ144 (XC2S15/30): P105, P104
* CS144 (XC2S15/30): M3, N3
* PQ208 (XC2S15/30/150): P55, P56
* FG256 (XC2S150): P4, R4
* FG456 (XC2S150): V6, Y5
For more information on the Spartan-3A and its Suspend Mode, see the Spartan-3A FPGA Family User Guide:
For more information about the CoolRunner XPLA3 devices, visit the CoolRunner documentation landing page at: