DSPB56720CAG Freescale Semiconductor, DSPB56720CAG Datasheet - Page 11

• Manufacturer Part Number: DSPB56720CAG
• Description: DSP 24BIT AUD 200MHZ 144-LQFP
• Manufacturer: Freescale Semiconductor
• Series: Symphony™r
• Type: Audio Processorr

Specifications of DSPB56720CAG

• Interface: Host Interface, I²C, SAI, SPI
• Clock Rate: 200MHz
• Non-volatile Memory: External
• On-chip Ram: 744kB
• Voltage - I/o: 3.30V
• Voltage - Core: 1.00V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 144-LQFP
• Device Core Size: 24b
• Format: Fixed Point
• Clock Freq (max): 200MHz
• Mips: 200
• Device Input Clock Speed: 200MHz
• Program Memory Size: Not RequiredKB
• Operating Supply Voltage (typ): 1/3.3V
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 144
• Package Type: LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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
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