Datasheet
LM95214
SNIS146A –MARCH 2007–REVISED MARCH 2013
www.ti.com
Common Tcrit Hysteresis Register
The hysteresis register range is 0°C to 32°C. The value programmed in this register is used to modify all the limit
values for decreasing temperature.
Register Name Command Read/ D7 D6 D5 D4 D3 D2 D1 D0 POR
Byte Write Default
(Hex) (Hex)
Common Tcrit Hysteresis 0x5A R/W 0 0 0 16 8 4 2 1 0x0A
Bit(s) Bit Name Read/ Description
Write
7 0 RO Read only bit will always report "0".
6 0 RO Read only bit will always report "0".
5 0 RO Read only bit will always report "0".
4 16 R/W bit weight 16°C
3 8 R/W bit weight 8°C
2 4 R/W bit weight 4°C
1 2 R/W bit weight 2°C
0 1 R/W bit weight 1°C
IDENTIFICATION REGISTERS
Register Name Command Read/ D7 D6 D5 D4 D3 D2 D1 D0 POR
Byte Write Default
(Hex) (Hex)
Manufacturer ID 0xFE RO 0 0 0 0 0 0 0 1 0x01
Revision ID 0xFF RO 0 1 1 1 1 0 1 1 0x7B
Applications Hints
The LM95214 can be applied easily in the same way as other integrated-circuit temperature sensors, and its
remote diode sensing capability allows it to be used in new ways as well. It can be soldered to a printed circuit
board, and because the path of best thermal conductivity is between the die and the pins, its temperature will
effectively be that of the printed circuit board lands and traces soldered to the LM95214's pins. This presumes
that the ambient air temperature is almost the same as the surface temperature of the printed circuit board; if the
air temperature is much higher or lower than the surface temperature, the actual temperature of the LM95214 die
will be at an intermediate temperature between the surface and air temperatures. Again, the primary thermal
conduction path is through the leads, so the circuit board temperature will contribute to the die temperature much
more strongly than will the air temperature.
To measure temperature external to the LM95214's die, incorporates remote diode sensing technology. This
diode can be located on the die of a target IC, allowing measurement of the IC's temperature, independent of the
LM95214's temperature. A discrete diode can also be used to sense the temperature of external objects or
ambient air. Remember that a discrete diode's temperature will be affected, and often dominated, by the
temperature of its leads. Most silicon diodes do not lend themselves well to this application. It is recommended
that an MMBT3904 transistor base emitter junction be used with the collector tied to the base.
The LM95214 can measure a diode-connected transistor such as the MMBT3904 or the thermal diode found in
an AMD processor. The LM95214 has been optimized to measure the MMBT3904 remote thermal diode the
offset register can be used to calibrate for other thermal diodes easily. The LM95214 does not include
TruTherm™ technology that allows sensing of sub-micron geometry process thermal diodes. For this application
the LM95234 would be better suited.
The LM95234 has been specifically optimized to measure the remote thermal diode integrated in a typical Intel
processor on 65 nm or 90 nm process or an MMBT3904 transistor. Using the Remote Diode Model Select
register found in the LM95234 any of the four remote inputs can be optimized for a typical Intel processor on 65
nm or 90 nm process or an MMBT3904.
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