The MPC2105A/B and the MPC2106A/B are designed to provide burstable, high performance L2 cache for the PowerPC 60x microprocessor family in conformance with the PowerPC Reference Platform (PReP) and the PowerPC Common Hardware Reference Platform (CHRP) specifications. The MPC2105A/B and MPC2106A/B utilize synchronous BurstRAMs. The modules are configured as 64K x 72, and 128K x 72 bits in a 178 (89 x 2) pin DIMM format. The MPC2105A/B uses four of the 3 V 64K x 18; the MPC2106A/B uses eight of the 3 V 64K x 18. For tag bits, a 5 V cache tag RAM configured as 16K x 12 for tag field plus 16K x 2 for valid and dirty status bits is used. Bursts can be initiated with the ADS signal. Subsequent burst addresses are generated internal to the BurstRAM by the CNTEN signal. Write cycles are internally self timed and are initiated by the rising edge of the clock (CLKx) inputs. Eight write enables are provided for byte write control. Presence detect pins are available for auto configuration of the cache control. The module family pinout will support 5 V and 3.3 V components for a clear path to lower voltage and power savings. Both power supplies must be connected. All of these cache modules are plug and pin compatible with each other.