GXLV Datasheet, PDF (190/247 Pages) National Semiconductor (TI) – Geode™ GXLV Processor Series Low Power Integrated x86 Solutions

Electrical Specifications (Continued)
6.5 DC CHARACTERISTICS
All DC parameters and current measurements in this section were measured under the operating conditions listed in
Table 6-4 on page 189.
6.5.1 Input/Output DC Characteristics
Table 6-5 shows the input/output DC parameters for all the devices in the GXLV processor series.
Table 6-5. DC Characteristics
Symbol Parameter
Min
Typ
Max Units Comments
V_OL
Output Low Voltage
V_OH
Output High Voltage
2.4
I_I
Input Leakage Current for all input pins
except those with internal pull up/pull
downs (PU/PDs).
I_IH
Input Leakage Current for all pins with
internal PDs.
I_IL
Input Leakage Current for all pins with
internal PUs.
C_IN
C_OUT
C_CLK
Note:
Input Capacitance
Output or I/O Capacitance
CLK Capacitance
Not 100% tested.
0.4
±10
200
–400
16
16
12
V
I_OL = 5 mA
V
I_OH = –2 mA
µA
0 < V_IN < V_CC3,
See Table 6-2
µA V_IH = 2.4 V,
See Table 6-2
µA V_IL = 0.35 V,
See Table 6-2
pF f = 1 MHz, Note
pF f = 1 MHz, Note
pF f = 1 MHz, Note
6.5.2 DC Current
DC current is not a simple measurement. The CPU has
four power states and two functional characteristics that
determine how much current the processor uses at any
given point in time.
6.5.2.1 Definition of CPU Power States
The following DC characteristic tables list CPU core and
I/O current for four distinct CPU power states:
• On: All internal and external clocks with respect to the
processor are running and all functional blocks inside
the processor (CPU core, memory controller, display
controller, etc.) are actively generating cycles. This is
equivalent to the ACPI specification’s"S0" state.
• Active Idle: The CPU core has been halted, all other
functional blocks (including the display controller for
refreshing the display) are actively generating cycles.
This state is entered when a HLT instruction is
executed by the CPU core or the SUSP# pin is
asserted. From a user’s perspective, this state is indis-
tinquishable from the "On" state and is equivalent to the
ACPI specification’s"S1" state.
• Standby: The CPU core has been halted and all
internal clocks have been shut down. Externally, the
SYSCLK input continues to be driven. This is equiva-
lent to the ACPI specification’s"S2" or "S3" state.
• Sleep: Very similar to "Standby" except that the
SYSCLK input has been shut down as well. This is the
lowest power state the processor can be in with voltage
still applied to the device’s core and I/O supply pins.
This is equivalent to the ACPI specification’s "S4BIOS"
state.
6.5.2.2 Definition and Measurement Techniques of
CPU Current Parameters
The following two parameters indicate processor current
while in the "On" state:
• Typical Average: Indicates the average current used
by the processor while in the “On” state. This is
measured by running typical Windows applications in a
typical display mode. In this case, 800x600x8 bpp at 75
Hz, 50 MHz DCLK using a background image of
vertical stripes (4-pixel wide) alternating between black
and white with power management disabled (to guar-
antee that the processor never goes into the Active Idle
state). This number is provided for reference only since
it can vary greatly depending on the usage model of
the system.
Note:
This typical average should not be confused with
the typical power numbers shown in Table 6-1 on
page 184. The numbers in Table 6-1 are based on
a combination of “On (Typical Average)” and
“Active Idle” states.
• Absolute Maximum: Indicates the maximum instanta-
neous current used by the processor. CPU core current
is measured by running the Landmark Speed 200^™
benchmark test (with power management disabled)
and measuring the peak current at any given instant
during the test. I/O current is measured by running
Microsoft Windows 98 and using a background image
of vertical stripes (1-pixel wide) alternating between
black and white at the maximum display resolution of
1280x1024x8 bpp at 75 Hz, 135 MHz DCLK.
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