SCPA033
11 Migration to the PCI1520 from the PCI1420
The major differences between the PCI1520 and PCI1420 are pinout, lower power consumption, and lower cost. The pinout is changed on the PCI1520 in order to incorporate an internal voltage regulator which allows the core to operate at 2.5V. When moving from the PCI1225 to the PCI1520, please see Section 13 for the differences between the PCI1225 and PCI1420 in addition to the changes from this section.
11.1Hardware and Pin Assignment Changes
•The pinout on the PCI1520 is significantly changed from the PCI1420. This requires a PCB redesign.
•A low dropout voltage regulator is integrated into the PCI1520 to supply 2.5V core voltage. A voltage regulator enable pin (VR_EN#) has been added in place of one of the VCCP pins. A core voltage input/output (VRPORT) pin has been added in place of the VCCI pin. This pin is used to either input core voltage or allow for an external 1.0µF bypass capacitor depending on the value of VR_EN#. A typical implementation would enable the regulator by grounding VR_EN# and adding the bypass capacitor from VRPORT to ground. For further details, see the datasheet.
•The PCI1520 does not have a VCCI pin. Signals clamped to VCCI on the PCI1420 are clamped to VCCP on the PCI1520.
•A new power switch has been introduced for dual socket CardBus controllers. The TPS2226A is recommended for new designs although the TPS2216 and TPS2206 are still compatible with the PCI1520. All three power switches have very similar functionality and can be designed onto the same footprint.
•The PCI1520 has integrated pullup resistors on the two CCLKRUN#//WP(IOIS16#) terminals. All necessary pullup resistors on the PC Card interface have been integrated in the PCI1520.
•A switchable pullup/pulldown resistor has been implemented on the two CSTSCHG//BVD1(STSCHG#/RI#) terminals. The pullup is active when the 16BITCARD bit (bit 4 in the Socket Present State register) is ‘1’, otherwise the pulldown resistor is activated. This prevents unexpected PME# assertion.
PCI1520 Implementation Guide | 17 |
