Ultra-Low Voltage Intel® Celeron® Processor — 650 MHz and 400 MHz
6.1
Thermal Diode
The ULV Intel® Celeron® processor has an on-die thermal diode that should be used to monitor the
die temperature (TJ). A thermal sensor located on the motherboard, or a stand-alone measurement
kit, should monitor the die temperature of the processor for thermal management or
instrumentation purposes. Tables 42 and 43 provide the diode interface and specifications.
Note: The reading of the thermal sensor connected to the thermal diode will not necessarily reflect the
temperature of the hottest location on the die. This is due to inaccuracies in the thermal sensor, on-
die temperature gradients between the location of the thermal diode and the hottest location on the
die, and time based variations in the die temperature measurement. Time based variations may
occur when the sampling rate of the thermal diode (by the thermal sensor) is slower than the rate at
which the TJ temperature may change.
Table 42. Thermal Diode Interface
Signal Name
Pin/Ball Number
Signal Description
THERMDA
THERMDC
AF13
AF14
Thermal diode anode
Thermal diode cathode
Table 43. Thermal Diode Specifications
Symbol
Parameter
Min
Typ
Max
Unit
Notes
n
n
Diode Ideality Factor (5-150 µA)
Diode Ideality Factor (5-300 µA)
1.0011
1.0003
1.0067
1.0091
1.0122
1.0178
1, 2, 3, 4, 6
1, 2, 3, 5, 6
NOTES:
1. Intel does not support or recommend operation of the thermal diode under reverse bias. Intel does not
support or recommend operation of the thermal diode when the processor power supplies are not within
their specified tolerance range.
2. Characterized at 100° C.
3. Not 100% tested. Specified by design/characterization.
4. Specified for Forward Bias Current = 5 µA (min) and 150 µA (max).
5. Specified for Forward Bias Current = 5 µA (min) and 300 µA (max).
6. The ideality factor, n, represents the deviation from ideal diode behavior as exemplified by the diode
equation: Where Is = saturation current, q = electronic charge, Vd = voltage across the diode,
k = Boltzmann Constant, and T = absolute temperature (Kelvin).
IFW = IS ⋅ (eqVD – 1)
66
Datasheet
INTEL [ INTEL ]
