DSP56321VF275 Freescale, DSP56321VF275 Datasheet - Page 63

• Manufacturer Part Number: DSP56321VF275
• Manufacturer: Freescale

Specifications of DSP56321VF275

• Device Core Size: 24b
• Format: Fixed Point
• Clock Freq (max): 275MHz
• Mips: 275
• Device Input Clock Speed: 275MHz
• Ram Size: 576KB
• Operating Supply Voltage (typ): 1.6/3.3V
• Operating Supply Voltage (min): 1.5/3/3/3/3/3/3V
• Operating Temp Range: -40C to 100C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 196
• Package Type: MA-BGA
• Lead Free Status / RoHS Status: Not Compliant

4.3 Power Consumption Considerations
Power dissipation is a key issue in portable DSP applications. Some of the factors affecting current consumption
are described in this section. Most of the current consumed by CMOS devices is alternating current (ac), which is
charging and discharging the capacitances of the pins and internal nodes.
Current consumption is described by this formula:
Where:
Freescale Semiconductor
Note: Refer to EB610/D DSP56321/DSP56321T Power-Up Sequencing Guidelines for detailed information
For a Port A address pin loaded with 50 pF capacitance, operating at 3.3 V, with a 66 MHz clock, toggling at its maximum possible rate (33
MHz), the current consumption is expressed in Equation 4.
•
•
•
•
•
•
Consider all device loads as well as parasitic capacitance due to PCB traces when you calculate
capacitance. This is especially critical in systems with higher capacitive loads that could create higher
transient currents in the
All inputs must be terminated (that is, not allowed to float) by CMOS levels except for the three pins with
internal pull-up resistors (
The following pins must be asserted during the power-up sequence:
signal should be supplied before deassertion of
EXTAL is stable or other “required
circuitry can be in an uninitialized state that may result in significant power consumption and heat-up.
Designs should minimize this condition to the shortest possible duration.
Ensure that during power-up, and throughout the DSP56321 operation,
the
If multiple DSP devices are on the same board, check for cross-talk or excessive spikes on the supplies due
to synchronous operation of the devices.
The Port A data bus (
last output value even when the internal signal is tri-stated. Typically, no pull-up or pull-down resistors
should be used with these signal lines. However, if the DSP is connected to a device that requires pull-up
resistors (such as an MPC8260), the recommended resistor value is 10 KΩ or less. If more than one DSP
must be connected in parallel to the other device, the pull-up resistor value requirement changes as
follows:
— 2 DSPs = 5 KΩ (mask sets 0K91M and 1K91M)/7 KΩ (mask set 0K93M) or less
— 3 DSPs = 3 KΩ (mask sets 0K91M and 1K91M)/4 KΩ (mask set 0K93M) or less
— 4 DSPs = 2 KΩ (mask sets 0K91M and 1K91M)/3 KΩ (mask set 0K93M) or less
— 5 DSPs = 1.5 KΩ (mask sets 0K91M and 1K91M)/2 KΩ (mask set 0K93M) or less
— 6 DSPs = 1 KΩ (mask sets 0K91M and 1K91M)/1.5 KΩ (mask set 0K93M) or less
about minimizing power consumption during startup.
Equation 3:
V
CCQL
voltage level.
C
V
f
I
=
C
D[0–23]
×
V
V
=
=
=
CC
TRST
×
), HI08, ESSI0, ESSI1, SCI, and timers all use internal keepers to maintain the
f
and
node/pin capacitance
voltage swing
frequency of node/pin toggle
Example 4-1. Current Consumption
,
TMS
GND
DSP56321 Technical Data, Rev. 11
RESET
,
circuits.
DE
).
duration” conditions are met (see Table 2-7), the device
RESET
. If the V
CC
reaches the required level before
RESET
Power Consumption Considerations
V
CCQH
and
is always higher or equal to
TRST
. A stable
EXTAL
4-3