beautypg.com

AMD ATHLON 8 User Manual

Page 97

background image

Appendix A - Thermal Diode Calculations

85

25175H—March 2003

AMD Athlon™ XP Processor Model 8 Data Sheet

Preliminary Information

The formulas in Equation (3) and Equation (4) can be used to
calculate the temperature offset for temperature sensors that
do not employ series resistance cancellation. The result is
added to the value measured by the temperature sensor.
Contact the vendor of the temperature sensor being used for
the value of n

f,TS

. Refer to the document, On-Die Thermal Diode

Characterization, order# 25443, for further details.

Equation (3) shows the equation for calculating the lumped
ideality factor (n

f, lumped

) in sensors that do not employ series

resistance cancellation.

Equation (4) shows the equation for calculating temperature
offset (T

offset

) in sensors that do not employ series resistance

cancellation.

Equation (5) is the temperature offset for temperature sensors
that utilize series resistance cancellation. Add the result to the
value measured by the temperature sensor. Note that the value
of n

f,TS

in Equation (5) may not equal the value used in

Equation (4).

(3)

n

f lumped

,

n

f actual

,

=

R

T

I

high

I

low

(

)

k

q

--- T

die spec

,

273.15

+

(

)

I

high

I

low

--------

ln

----------------------------------------------------------------------

+

(4)

T

of f s e t

T

die spec

,

273.15

+

(

)

=

1 n

f lumped

,

n

f TS

,

---------------

(5)

T

of f s e t

T

die spec

,

273.15

+

(

)

=

1

n

f

actual

,

n

f TS

,

---------------