DSPB56725AF Freescale Semiconductor, DSPB56725AF Datasheet - Page 11
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DSPB56725AF
Manufacturer Part Number
DSPB56725AF
Description
DSP 24BIT AUD 250MHZ 80-LQFP
Manufacturer
Freescale Semiconductor
Series
Symphony™r
Type
Audio Processorr
Specifications of DSPB56725AF
Interface
Host Interface, I²C, SAI, SPI
Clock Rate
250MHz
Non-volatile Memory
External
On-chip Ram
112kB
Voltage - I/o
3.30V
Voltage - Core
1.20V
Operating Temperature
0°C ~ 70°C
Mounting Type
Surface Mount
Package / Case
80-LQFP
Processor Series
DSP567xx
Core
56300
Leaded Process Compatible
Yes
Rohs Compliant
Yes
Peak Reflow Compatible (260 C)
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
DSPB56725AF
Manufacturer:
Freescale Semiconductor
Quantity:
10 000
2.4
Power dissipation is a key issue in portable DSP applications. Some of the factors which affect 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 the following formula:
The maximum internal current (I
operation conditions, which is not necessarily a real application case. The typical internal current (I
average switching of the internal buses on typical operating conditions.
For applications that require very low current consumption, do the following:
One way to evaluate power consumption is to use a current per MIPS measurement methodology to minimize specific board
effects (for example, to compensate for measured board current not caused by the DSP). Use the test algorithm, specific test
current measurements, and the following equation to derive the current per MIPS value.
Freescale Semiconductor
•
•
For a GPIO address pin loaded with 50 pF capacitance, operating at 3.3 V, and with a 150 MHz clock, toggling at
its maximum possible rate (75 MHz), the current consumption is
where
Minimize the number of pins that are switching.
Minimize the capacitive load on the pins.
where :
Power Consumption Considerations
F1 should be significantly less than F2. For example, F2 could be 66 MHz and F1 could be
33 MHz. The degree of difference between F1 and F2 determines the amount of precision
with which the current rating can be determined for an application.
C=node/pin capacitance
V=voltage swing
f=frequency of node/pin toggle
I
I
F2=high frequency (any specified operating frequency)
F1=low frequency (any specified operating frequency lower than F2)
typF2
typF1
Symphony
=current at F2
=current at F1
CCI
max) value reflects the typical possible switching of the internal buses on best-case
I/MIPS = I/MHz = (I
™
Example 1. Power Consumption Example
DSP56720/DSP56721 Multi-Core Audio Processors, Rev. 5
I
=
50
x
10 12
I
=
–
C
×
x
typF2
3.3
NOTE
V
×
x
75
- I
f
typF1
x
10 6
)/(F2 - F1)
=
12.375mA
CCItyp
) value reflects the
Eqn. 2
Eqn. 1
Eqn. 3
11