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41978 AMD RS690M Databook 3.06
© 2008 Advanced Micro Devices, Inc.
5-6
Proprietary
RS690M Thermal Characteristics
5.2.2
Thermal Diode Characteristics
The RS690M has an on-die thermal diode, with its positive and negative terminals connected to the
THERMALDIODE_P and THERMALDIODE_N pins respectively. Combined with a thermal sensor circuit, the diode
temperature, and hence the ASIC temperature, can be derived from a differential voltage reading (
∆
V
). The equation
relating
T
to
∆
V
is given below:
where:
∆
V
= Difference of two base-to-emitter voltage readings, one using current = I and the other using current =
N x I
N
= Ratio of the two thermal diode currents (=10 when using an ADI thermal sensor, e.g. ADM 1020, 1030)
η
= Ideality factor of the diode
K
= Boltzman’s Constant
T
= Temperature in Kelvin
q
= Electron charge
The series resistance of the thermal diode (R
T
) must be taken into account as it introduces an error in the reading
(for every 1.0
Ω
, approximately 0.8
o
C is added to the reading). The sensor circuit should be calibrated to offset the
R
T
induced, plus any other known fixed error. Measured values of diode ideality factor and series resistance for the
diode circuit are defined in the
Thermal Design and Analysis Guidelines for the RS690 Product Family
.
Ambient Temperature
0
—
45
°
C
3
Thermal Design Power
—
8
—
W
4
Notes:
1 - The maximum operating case temperature is the die geometric top-center temperature measured via a thermocouple based on the
methodology given in the document
Thermal Design and Analysis Guidelines for the RS690 Product Family
(Chapter 10). This is the
temperature at which the functionality of the chip is qualified.
2 - The maximum absolute rated junction temperature is the junction temperature at which the device can operate without causing
damage to the ASIC. This temperature can be measured via the integrated thermal diode described in the next section.
3 - The ambient temperature is defined as the temperature of the local intake air to the thermal management device. The maximum
ambient temperature is dependent on the heat sink's local ambient conditions as well as the chassis' external ambient, and the value
given here is based on AMD’s reference heat sink solution for the RS690M. Refer to Chapter 7 in the
Thermal Design and Analysis
Guidelines for the RS690 Product Family
for heatsink and thermal design guidelines. Refer to Chapter 5 of the above mentioned
document for details of ambient conditions.
4 - The Thermal Design Power (TDP) is defined as the worst-case power dissipation while running currently available applications at
nominal voltages and at the maximum operating temperature. Since the core power of modern ASICs using 90nm and smaller process
technology can vary significantly, parts specifically screened for higher core power were used for TDP measurement.The TDP is
intended only as a design reference. It is not an absolute maximum power under all conditions. The value shown here is a preliminary
estimate only.
Table 5-9 RS690M Thermal Limits (Continued)
Parameter
Minimum
Nominal
Maximum
Unit
Note
V
∆
η
K
×
T
×
N
( )
ln
×
q
--------------------------------------------
=
Содержание RS690M
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