KMC7448HX1700LD Datasheet, PDF (15/60 Pages) Freescale Semiconductor, Inc – RISC Microprocessor Hardware Specifications

Electrical and Thermal Characteristics
5.2 AC Electrical Characteristics
This section provides the AC electrical characteristics for the MPC7448. After fabrication, functional parts
are sorted by maximum processor core frequency as shown in Section 5.2.1, “Clock AC Specifications,”
and tested for conformance to the AC specifications for that frequency. The processor core frequency,
determined by the bus (SYSCLK) frequency and the settings of the PLL_CFG[0:5] signals, can be
dynamically modified using dynamic frequency switching (DFS). Parts are sold by maximum processor
core frequency; see Section 11, “Part Numbering and Marking,” for information on ordering parts. DFS is
described in Section 9.7.5, “Dynamic Frequency Switching (DFS).”
5.2.1 Clock AC Specifications
Table 8 provides the clock AC timing specifications as defined in Figure 3 and represents the tested
operating frequencies of the devices. The maximum system bus frequency, f_SYSCLK, given in Table 8, is
considered a practical maximum in a typical single-processor system. This does not exclude
multi-processor systems, but these typically require considerably more design effort to achieve the
maximum rated bus frequency. The actual maximum SYSCLK frequency for any application of the
MPC7448 will be a function of the AC timings of the microprocessor(s), the AC timings for the system
controller, bus loading, circuit board topology, trace lengths, and so forth, and may be less than the value
given in Table 8.
MPC7448 RISC Microprocessor Hardware Specifications, Rev. 4
Freescale Semiconductor
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