MPC7457 datasheet(16/68 Pages) FREESCALE

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MPC7457 RISC Microprocessor Hardware Specifications, Rev. 5

Freescale Semiconductor

Electrical and Thermal Characteristics

Figure 3 provides the SYSCLK input timing diagram.

Figure 3. SYSCLK Input Timing Diagram

5.2.2

Processor Bus AC Specifications

Table 9 provides the processor bus AC timing specifications for the MPC7457 as defined in Figure 4 and Figure 5.

Timing specifications for the L3 bus are provided in Section 5.2.3, “L3 Clock AC Specifications.”

SYSCLK cycle time

tSYSCLK

6.0

SYSCLK rise and fall time

tKR, tKF

—

1.0

—

1.0

—

1.0

—

1.0

SYSCLK duty cycle measured

at OVDD/2

tKHKL/

tSYSCLK

SYSCLK cycle-to-cycle jitter

—

150

—

150

—

150

—

150

5, 6

Internal PLL relock time

—

100

—

100

—

100

—

100

µs

Notes:

Caution: The SYSCLK frequency and PLL_CFG[0:4] settings must be chosen such that the resulting SYSCLK (bus)

frequency, CPU (core) frequency, and PLL (VCO) frequency do not exceed their respective maximum or minimum operating

frequencies. Refer to the PLL_CFG[0:4] signal description in Section 1.9.1, “PLL Configuration,” for valid PLL_CFG[0:4]

settings.

Assumes lightly-loaded, single-processor system; see Section 5.2.1, “Clock AC Specifications” for more information.

Rise and fall times for the SYSCLK input measured from 0.4 to 1.4 V.

Timing is guaranteed by design and characterization.

Guaranteed by design.

The SYSCLK driver’s closed loop jitter bandwidth should be less than 1.5 MHz at –3 dB.

Relock timing is guaranteed by design and characterization. PLL-relock time is the maximum amount of time required for

PLL lock after a stable VDD and SYSCLK are reached during the power-on reset sequence. This specification also applies

when the PLL has been disabled and subsequently re-enabled during sleep mode. Also note that HRESET must be held

asserted for a minimum of 255 bus clocks after the PLL-relock time during the power-on reset sequence.

Table 8. Clock AC Timing Specifications (continued)

At recommended operating conditions. See Table 4.

Characteristic

Symbol

Maximum Processor Core Frequency

Unit

Notes

867 MHz

1000 MHz

1200 MHz

1267 MHz

Min

Max

Min

Max

Min

Max

Min

Max

SYSCLK

CVIH

CVIL

VM = Midpoint Voltage (OVDD/2)

tSYSCLK

tKR

tKF

tKHKL

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