ds96-039wdsp ETC-unknow, ds96-039wdsp Datasheet - Page 82

• Manufacturer Part Number: ds96-039wdsp
• Description: Clarification Serial Control Register Description Dsp1620/27/28/29 Devices
• Manufacturer: ETC-unknow

DSP1628 Digital Signal Processor
8 Device Characteristics
8.4 Package Thermal Considerations
The recommended operating temperature specified above is based on the maximum power, package type, and
maximum junction temperature. The following equations describe the relationship between these parameters. If the
applications' maximum power is less than the worst-case value, this relationship determines a higher maximum am-
bient temperature or the maximum temperature measured at top dead center of the package.
where T
dead center of the package.
Maximum Junction Temperature (T
100-pin BQFP Maximum Thermal Resistance in Still-Air-Ambient (
100-pin BQFP Maximum Thermal Resistance, Junction to Top Dead Center (
Maximum Junction Temperature (T
100-pin TQFP Maximum Thermal Resistance in Still-Air-Ambient (
100-pin TQFP Maximum Thermal Resistance, Junction to Top Dead Center (
Maximum Junction Temperature (T
144-pin PBGA Maximum Thermal Resistance in Still-Air-Ambient (
144-pin PBGA Maximum Thermal Resistance, Junction to Top Dead Center (
WARNING:
The applications' maximum power, the package type, and the maximum ambient temperature determine the maxi-
mum activity factors for the error correction coprocessor as well as for the DSP core and its peripherals. The follow-
ing equations describe the relationship between these parameters. If the applications' maximum power is less than
the worst-case value, this relationship permits higher activity factors. For these calculations, refer to Section 4.13,
Power Management and Section 9.1, Power Dissipation.
where:
P
MIPS
AF
AF
AF
P
P
P
For example, for a TQFP device operating at 50 MIPS in a 3 V application with 40% ECCP activity, 100% DSP ac-
tivity, and 0% sleep activity, the equation would look like this:
The above example demonstrates the maximum operating capability in the TQFP package.
Note: The power calculations listed are for internal power dissipation only. The external power dissipation due to
80
ECCP
DSP
SLEEP
ECCP
DSP
SLEEP
output pins switching must also be included.
A
is the still-air ambient temperature and T
Due to package thermal constraints, proper precautions in the user's application should be
taken to avoid exceeding the maximum junction temperature of 100 C. Otherwise, the device
will be affected adversely.
= Maximum power in mW
= Device speed (internal clock speed
= Activity factor for error correction coprocessor (ECCP)
= Activity factor for DSP core and peripherals
= Activity factor for sleep mode operation = 1 – AF
= Power dissipation in mW for ECCP
= Power dissipation in mW for DSP core and peripherals
= Power dissipation in mW for sleep mode operation
P = MIPS x [AF
50 MIPS x [0.4 (35 mW/50 MIPS) + 1.0(125 mW/50 MIPS) + 0] = 139 mW
(continued)
J
J
J
ECCP
) in 100-Pin BQFP ............................................................................ 100 C
) in 100-Pin TQFP ............................................................................ 100 C
) in 144-Pin PBGA............................................................................ 100 C
139 mW x 64 C/W + 85 C = 94 C <= 100 C
(P
ECCP
T
TDC
T
/MIPS) + AF
A
TDC
P x
= T
= T
10
J
J
is the temperature measured by a thermocouple at the top
– P x
– P x
JA
6)
+ 85 C <= 125 C
DSP
J-TDC
JA
(P
DSP
DSP
JA
JA
JA
) ................................................ 64 C/W
) ................................................ 55 C/W
) .....................TBD (estimated 30 C/W)
/MIPS) + (1 – AF
J-TDC
J-TDC
J-TDC
) ............................ 6 C/W
).......................... 12 C/W
)................................ TBD
DSP
Lucent Technologies Inc.
) (P
SLEEP
February 1997
/MIPS)]