SPEAR320 datasheet(46/73 Pages) STMICROELECTRONICS

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Electrical characteristics

SPEAr320

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Doc ID 16755 Rev 5

6.3

DC electrical characteristics

The recommended operating conditions are listed in the following table:

6.4

Overshoot and undershoot

This product can support the following values of overshoot and undershoot.

If the amplitude of the overshoot/undershoot increases (decreases), the ratio of

overshoot/undershoot width to the pulse width decreases (increases). The formula relating

the two is:

Amplitude of OS/US = 0.75*(1- ratio of OS (or US) duration with respect to pulse width)

Note:

The value of overshoot/undershoot should not exceed the value of 0.5 V. However, the

duration of the overshoot/undershoot can be increased by decreasing its amplitude.

Based on bench measurements for worst case silicon under worst case operating conditions. Devices

tested with operating system running, CPU and DDR2 running at 333 MHz, DDR2 driven by PLL2, SDRAM

and all on-chip peripherals and internal modules enabled.

1.2 V current and power are primarily dependent on the applications running and the use of internal chip

functions (DMA, USB, Ethernet, and so on).

3.3 V current and power are primarily dependent on the capacitive loading, frequency, and utilization of the

external buses.

Table 18.

Recommended operating conditions

Symbol

Parameter

Min

Typ

Max

Unit

VDD 1.2

Supply voltage for the core

1.14

1.2

1.3

VDD 3.3

Supply voltage for the I/Os

3.3

3.6

VDD 2.5

PLL supply voltage(1)

For power supply filtering it is required to add an external ferrite inductor.

2.25

2.5

2.75

VDD 2.5

Oscillator supply voltage

2.25

2.5

2.75

VDD 1.8

Supply voltage for DRAM interface

1.70

1.8

1.9

VDD RTC

RTC supply voltage

1.3

1.5

1.8

Operating temperature

-40

°C

Table 19.

Overshoot and undershoot specifications

Parameter

3V3 I/Os

2V5 I/Os

1V8 I/Os

Amplitude

500 mV

Ratio of overshoot (or undershoot) duration with respect to

pulse width

1/3

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