LM95214CISD National Semiconductor, LM95214CISD Datasheet - Page 9

• Manufacturer Part Number: LM95214CISD
• Description: SENSOR, TEMP, 4-DIODE, 2-WIRE I/F
• Manufacturer: National Semiconductor

Specifications of LM95214CISD

• Ic Output Type: Current
• Sensing Accuracy Range: ± 1°C
• Supply Current: 0.57mA
• Supply Voltage Range: 3V To 3.6V
• Resolution (bits): 11bit
• Sensor Case Style: LLP
• No. Of Pins: 14
• Svhc: No SVHC
• Temperature Sensing Range: -40°C To +140°C
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Typical Performance Characteristics
1.0 Functional Description
LM95214 is an 11-bit digital temperature sensor with a 2-wire
System Management Bus (SMBus) interface that can monitor
the temperature of four remote diodes as well as its own tem-
perature. The LM95214 can be used to very accurately mon-
itor the temperature of up to four external devices such as
microprocessors, graphics processors or diode-connected
2N3904 transistor. Any device whose thermal diode can be
modeled by an MMBT3904 transistor will work well with the
LM95214.
The LM95214 reports temperature in two different formats for
+127.875°C/–128°C range and 0°C/255°C range. The
LM95214 has a Sigma-Delta ADC (Analog-to-Digital Con-
verter) core which provides the first level of noise imunity. For
improved performance in a noisy environment the LM95214
includes programmable digital filters for Remote Diode 1 and
2 temperature readings. When the digital filters are invoked
the resolution for Remote Diode 1 and 2 readings increases
to 0.03125°C. For maximum flexibility and best accuracy the
LM95214 includes offset registers that allow calibration of
other diode types.
Remote Temperature Reading Sensitivity to
Thermal Diode Filter Capacitance
Average Power Supply Current
Conversion Rate Effect on
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Diode fault detection circuitry in the LM95214 can detect the
absence or fault state of a remote diode: whether D+ is short-
ed to V
The LM95214 TCRIT1, TCRIT2 and TCRIT3 active low out-
puts are triggered when any unmasked channel exceeds its
corresponding programmable limit and can be used to shut-
down the system, to turn on the system fans or as a micro-
controller interrupt function. The current status of the
TCRIT1, TCRIT2 and TCRIT3 pins can be read back from the
status registers via the SMBus interface. Two of the remote
channels have two separate limits each that control the
TCRIT1 and TCRIT2 pins. The remaining two channels and
the local channel each have one limit to control both the
TCRIT1 and TCRIT2 pins. The TCRIT3 pin shares the limits
of the TCRIT2 pin but allows for different masking options. All
limits have a shared programmable hysteresis register.
Remote Diode 1 and 2 temperature channels have pro-
grammable digital filters while the other two remote temper-
ature channels utilize a fault-queue in order to avoid false
triggering the TCRIT pins.
LM95214 has a three-level address pin to connect up to 3
devices to the same SMBus master. LM95214 also has pro-
DD
Remote Diode Temperature Reading
, D- or ground, or whether D+ is floating.
Thermal Diode Capacitor or PCB
Leakage Current Effect on
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