NSC LM95233CISD

August 2006
LM95233
Dual Remote Diode and Local Temperature Sensor with
SMBus Interface, TCRITs and TruTherm™ Technology
General Description
LM95233 is an 11-bit digital temperature sensor with a 2-wire
System Management Bus (SMBus) interface that can monitor the temperature of two remote diodes as well as its own
temperature. The LM95233 can be used to very accurately
monitor the temperature of up to two external devices such
as microprocessors, graphics processors or diodeconnected 2N3904s. The LM95233’s TruTherm technology
allows sensing of 90nm or 65nm process thermal diodes
accurately.
The LM95233 reports temperature in two different formats
for +127.875˚C/–128˚C range and 0˚C/255˚C range. The
LM95233 TCRIT1, TCRIT2 and TCRIT3 outputs are triggered when any unmasked channel exceeds its corresponding programmable limit and can be used to shutdown the
system, to turn on the system fans or as a microcontroller
interrupt function. The current status of the TCRIT1, TCRIT2
and TCRIT3 pins can be read back from the status registers.
Mask registers are available for further control of the TCRIT
outputs.
LM95233’s remote temperature channels have programmable digital filters to minimize unwanted TCRIT events
when temperature spikes are encountered.
For optimum flexibility and accuracy each LM95233 channel
includes, registers for sub-micron process or 2N3904 diode
model selection as well as offset correction. A three level
address pin allows connection of up to 3 LM95233s to the
same SMBus master. The LM95233 includes power saving
functions such as: programmable conversion rate, shutdown
mode, and turn off of unused channels.
Features
n Accurately senses die temperature of 2 remote ICs or
diode junctions and local temperature
n TruTherm technology accurately senses sub-micron
process thermal diodes
n 0.125˚C LSb temperature resolution
n 0.03125˚C LSb remote temperature resolution with
digital filter enabled
n +127.875˚C/–128˚C and 0˚C/255˚C remote ranges
n Programmable digital filters and analog front end filter
n Remote diode fault detection, model selection and offset
correction
n Mask and status register support
n 3 programmable TCRIT outputs with programmable
shared hysteresis
n Programmable conversion rate and shutdown mode
one-shot conversion control
n SMBus 2.0 compatible interface, supports TIMEOUT
n Three-level address pin
n 14-pin LLP package
Key Specifications
j Local Temperature Accuracy
j Remote Diode Temperature
Accuracy
j Supply Voltage
j Average Supply Current (1Hz
± 2.0 ˚C (max)
± 0.75 ˚C (max)
3.0 V to 3.6 V
0.5 mA (typ)
conversion rate)
Applications
n Processor/Computer System Thermal Management
(e.g. Laptop, Desktop, Workstations, Server)
n Electronic Test Equipment
n Office Electronics
Connection Diagram
LLP-14
20206301
TOP VIEW
TruTherm™ is a trademark of National Semiconductor Corporation.
© 2006 National Semiconductor Corporation
DS202063
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LM95233 Dual Remote Diode and LocalTemperature Sensor with SMBus Interface, TCRITs and
TruTherm Technology
ADVANCE INFORMATION
LM95233
Ordering Information
Package
Marking
NS Package
Number
Transport
Media
LM95233CISD
95233CI
SDA14B (LLP-14)
1000 Units on Tape and Reel
LM95233CISDX
95233CI
SDA14B (LLP-14)
4500 Units on Tape and Reel
Part Number
Simplified Block Diagram
20206302
Pin Descriptions
Label
Pin #
NC
1
No Connect
Not connected. May be left floating, connected to
GND or VDD.
VDD
2
Positive Supply Voltage
Input
DC Voltage from 3.0 V to 3.6 V. VDD should be
bypassed with a 0.1µF capacitor in parallel with
100pF. The 100pF capacitor should be placed as
close as possible to the power supply pin. Noise
should be kept below 200 mVp-p, a 10 µF capacitor
may be required to achieve this.
NC
3
No Connect
Not connected. May be left floating, connected to
GND or VDD.
NC
4
No Connect
Not connected. May be left floating, connected to
GND or VDD.
D−
5
Diode Return Current Sink
To all Diode Cathodes. Common D- pin for all two
remote diodes.
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Function
Typical Connection
2
LM95233
Pin Descriptions
(Continued)
Label
Pin #
D2+
6
Diode Current Source
Function
To second Diode Anode. Connected to remote
discrete diode-connected transistor junction or to the
diode-connected transistor junction on a remote IC
whose die temperature is being sensed. A capacitor
is not required between D2+ and D-. A 100 pF
capacitor between D2+ and D- can be added and
may improve perfomance in noisy systems. Float
this pin if this thermal diode is not used.
Typical Connection
D1+
7
Diode Current Source
To first Diode Anode. Connected to remote discrete
diode-connected transistor junction or to the
diode-connected transistor junction on a remote IC
whose die temperature is being sensed. A capacitor
is not required between D1+ and D-. A 100 pF
capacitor between D1+ and D- can be added and
may improve perfomance in noisy systems. Float
this pin if this thermal diode is not used.
GND
8
Power Supply Ground
System low noise ground.
A0
9
Dgital Input
SMBus slave address select pin. Selects one of
three addresses. Can be tied to VDD, GND, or to the
middle of a resistor divider connected between VDD
and GND.
TCRIT1
10
Digital Output, Open-Drain
Critical temperature output 1. Requires pull-up
resistor. Active "LOW".
TCRIT2
11
Digital Output, Open-Drain
Critical temperature output 2. Requires pull-up
resistor. Active "LOW".
SMBDAT
12
SMBus Bi-Directional Data
Line, Open-Drain Output
From and to Controller; may require an external
pull-up resistor
SMBCLK
13
SMBus Clock Input
From Controller; may require an external pull-up
resistor
TCRIT3
14
Digital Output, Open-Drain
Critical temperature output 3. Requires pull-up
resistor. Active "LOW".
3
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LM95233
Typical Application
20206303
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4
inches (millimeters)
14-Lead Molded Leadless Leadframe Package (LLP),
Order Number LM95233CISD or LM95233CISDX
NS Package Number SDA14B
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves
the right at any time without notice to change said circuitry and specifications.
For the most current product information visit us at www.national.com.
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LM95233 Dual Remote Diode and LocalTemperature Sensor with SMBus Interface, TCRITs and
TruTherm Technology
Physical Dimensions
unless otherwise noted