LM95235EVAL/NOPB National Semiconductor, LM95235EVAL/NOPB Datasheet - Page 10

• Manufacturer Part Number: LM95235EVAL/NOPB
• Description: BOARD EVALUATION LM95235
• Manufacturer: National Semiconductor
• Series: PowerWise®, TruTherm®r

Specifications of LM95235EVAL/NOPB

• Sensor Type: Temperature
• Sensing Range: -40°C ~ 125°C
• Interface: SMBus (2-Wire/I²C)
• Sensitivity: ±1°C
• Voltage - Supply: 3 V ~ 3.6 V
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: LM95235
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LM95235EVAL

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9.
10. Configuration Register 2 defaults to 1Fh. This sets the
1.3 SMBus INTERFACE
The LM95235 operates as a slave on the SMBus, so the
SMBCLK line is an input and the SMBDAT line is bidirectional.
The LM95235 never drives the SMBCLK line and it does not
support clock stretching. According to SMBus specifications,
the LM95235 has a 7-bit slave address. Three SMBus ad-
dresses can be selected by connecting pin 6 (A0) to either
Low, Mid-Supply or High voltages. The address selection ta-
ble below shows the possible selections.
The OS/A0 pin, after power-up, defaults as an address select
input pin (A0). After power-up, the OS/A0 pin can only be
programmed as an OS output when it is in the “High” state.
Therefore, 4Ch is the only valid slave address that can be
used when the OS/A0 pin is programmed to function as an
OS output. When the OS/A0 pin is programmed to function
as an A0 input the LM95235 will immediately detect the state
of this pin to determine its SMBus slave address. The
LM95235 does not latch the state of the A0 pin when it is
functioning as an input.
1.4 DIGITAL FILTER
In order to suppress erroneous remote temperature readings
due to noise, the LM95235 incorporates a digital filter for the
Remote Temperature Channel. The filter is accessed in the
Configuration Register 2, bits D2 (FE1) and D1(FE0). The fil-
ter can be set according to the following table.
Configuration Register 1 defaults to 00h. This sets the
LM95235 as follows:
A.
B.
LM95235 as follows:
A.
B.
C. Diode Fault Mask bit for TCRIT defaults to 1.
D. Diode Fault Mask bit for OS defaults to 0.
E.
State of the A0 Pin
The STOP/RUN defaults to the active/converting
mode.
The Local and Remote TCRIT and OS Masks are
reset to 0.
Remote Diode digital filter defaults on.
The Remote Diode mode defaults to a typical Intel
processor on 65/90 nm process.
Pin 6 Function defaults to Address Input function
(A0).
Mid-Supply
High
Low
FE1
0
0
1
1
FE0
0
1
0
1
SMBus Device Address
HEX
Filter Setting
4C
18
29
Reserved
Reserved
Filter Off
Filter On
001 1000
010 1001
100 1100
Binary
10
Figure 2 depicts the filter output in response to a step input
and an impulse input.
c) Impuse response with input transients greater than 4°
Figure 3 shows the filter in use in a typical Intel processor on
a 65/90 nm process system. Note that the two curves have
been purposely offset for clarity. Inserting the filter does not
induce an offset as shown.
b) Impulse response with input transients less than 4°C
FIGURE 2. Filter Impulse and Step Response Curves
a) Seventeen and fifty degree step response
C
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