LM95213EB/NOPB National Semiconductor, LM95213EB/NOPB Datasheet - Page 11

• Manufacturer Part Number: LM95213EB/NOPB
• Description: BOARD EVALUATION FOR LM95213
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LM95213EB/NOPB

• Sensor Type: Temperature
• Sensing Range: -40°C ~ 140°C
• Interface: SMBus (2-Wire/I²C)
• Sensitivity: ±1°C
• Voltage - Supply: 3 V ~ 3.6 V
• Embedded: No
• Utilized Ic / Part: LM95213
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LM95213EB

1.4 TEMPERATURE CONVERSION SEQUENCE
Each of the 3 temperature channels of LM95213 can be
turned OFF independent from each other via the Channel
Enable Register. Turning off unused channels will increase
the conversion speed in the fastest conversion speed mode.
If the slower conversion speed settings are used, disabling
unused channels will reduce the average power consumption
of LM95213.
1.5 DIGITAL FILTER
In order to suppress erroneous remote temperature readings
due to noise as well as increase the resolution of the temper-
FIGURE 3. Digital Filter Response in a typical processor
Figure 3 shows the filter in use in a typical processor system.
Note that the two curves have been purposely offset for clar-
ity. Inserting the filter does not induce an offset as shown.
a) Seventeen and fifty degree step
system. The filter curves were purposely offset for
A0 Pin State
Mid-Supply
High
Low
response
SMBus Device Address A[6:0]
clarity.
Hex
2Ah
2Bh
18h
30013825
FIGURE 2. Filter Impulse and Step Response Curves
001 1000
010 1010
010 1011
Binary
b) Impulse response with input
30013828
transients less than 4°C
11
ature, the LM95213 incorporates a digital filter for Remote 1
and 2 Temperature Channels. When a filter is enabled the
filtered readings are used for the TCRIT comparisons. There
are two possible digital filter settings that are enabled through
the Filter Setting Register at register address 0Fh. The filter
for each channel can be set according to the following table:
Figure 2 describes the filter output in response to a step input
and an impulse input.
1.6 TEMPERATURE DATA FORMAT
Temperature data can only be read from the Local and Re-
mote Temperature value registers. The data format for all
temperature values is left justified 16-bit word available in two
8-bit registers. Unused bits will always report "0". All temper-
ature data is clamped and will not roll over when a tempera-
ture exceeds full-scale value.
Remote temperature data for all channels can be represented
by an 11-bit, two's complement word or unsigned binary word
with an LSb (Least Significant Bit) equal to 0.125°C.
Temperature
R1F[1:0] or R2F[1:0]
+0.125°C
−0.125°C
+125°C
+25°C
0
0
1
1
+1°C
−1°C
0°C
11-bit, 2's complement (10-bit plus sign)
30013826
0111 1101 0000 0000
0001 1001 0000 0000
0000 0001 0000 0000
0000 0000 0010 0000
0000 0000 0000 0000
1111 1111 1110 0000
1111 1111 0000 0000
0
1
0
1
c) Impulse response with input
transients great than 4°C
Binary
Filter (equivalent to Level 2
Enhanced Filter (Filter with
Digital Output
filter of the LM86/LM89)
transient noise clipping)
Filter Setting
Reserved
No Filter
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7D00h
FFE0h
1900h
0100h
0020h
0000h
FF00h
Hex
30013827