ADM1032ARM ,+-1C Remote and Local System Temperature MonitorSpecifications subject to change without notice.–2– REV. 0ADM1032ABSOLUTE MAXIMUM RATINGS* THERMAL
ADM1032ARM-1 ,High Accuracy, Remote Thermal Diode Monitor in Micro SOIC PackageAPPLICATIONSThis output can be used as an interrupt or as an SMBus alert.Desktop and Notebook Compu ..
ADM1032ARM-REEL ,High Accuracy, Remote Thermal Diode Monitor in Micro SOIC PackageSPECIFICATIONSParameter Min Typ Max Unit Test Conditions/CommentsPOWER SUPPLYSupply Voltage, V 3.0 ..
ADM1032ARM-REEL7 ,High Accuracy, Remote Thermal Diode Monitor in Micro SOIC PackageFEATURES PRODUCT DESCRIPTIONOn-Chip and Remote Temperature Sensing The ADM1032 is a dual-channel di ..
ADM1032ARMZ ,High Accuracy, Remote Thermal Diode Monitor in Micro SOIC PackageSPECIFICATIONSParameter Min Typ Max Unit Test Conditions/CommentsPOWER SUPPLYSupply Voltage, V 3.0 ..
ADM1032ARMZ-1 , 1C Remote and Local System Temperature Monitor
AH173 , INTERNAL PULL-UP HALL EFFECT LATCH FOR HIGH TEMPERATURE
AH173-WG-7-A , INTERNAL PULL-UP HALL EFFECT LATCH FOR HIGH TEMPERATURE
AH173-WL-7-A , INTERNAL PULL-UP HALL EFFECT LATCH FOR HIGH TEMPERATURE
AH173-WL-7-B , INTERNAL PULL-UP HALL EFFECT LATCH FOR HIGH TEMPERATURE
AH173WLA-A , Internal Pull-up Hall Effect Latch For High Temperature
AH174 , Inverted Output Hall Effect Latch For High Temperature
ADM1032AR-ADM1032ARM
+-1C Remote and Local System Temperature Monitor
REV.0
�1�C Remote and Local
System Temperature Monitor
FUNCTIONAL BLOCK DIAGRAM
FEATURES
On-Chip and Remote Temperature Sensing
Offset Registers for System Calibration
0.125�C Resolution/1�C Accuracy on Remote Channel
1�C Resolution/3�C Accuracy on Local Channel
Fast (Up to 64 Measurements per Second)
2-Wire SMBus Serial Interface
Supports SMBus Alert
Programmable Over/Under Temperature Limits
Programmable Fault Queue
Over-Temperature Fail-Safe THERM Output
Programmable THERM Limits
Programmable THERM Hysteresis
170 �A Operating Current
5.5 �A Standby Current
3 V to 5.5 V Supply
Small 8-Lead SO and Micro_SO Package
APPLICATIONS
Desktop Computers
Notebook Computers
Smart Batteries
Industrial Controllers
Telecomms Equipment
Instrumentation
Embedded SystemsPentium is a registered trademark of Intel Corporation.
*Patents 5,982,221, 6,097,239, 6,133,753, 6,169,442, 5,867,012.
PRODUCT DESCRIPTIONThe ADM1032 is a dual-channel digital thermometer and
under/over temperature alarm, intended for use in personal
computers and thermal management systems. The higher 1°C
accuracy offered allows systems designers to safely reduce
temperature guardbanding and increase system performance.
The device can measure the temperature of a microprocessor
using a diode-connected NPN or PNP transistor, which may be
provided on-chip or can be a low-cost discrete device such as
the 2N3906. A novel measurement technique cancels out the
absolute value of the transistor’s base emitter voltage, so that no
calibration is required. The second measurement channel mea-
sures the output of an on-chip temperature sensor, to monitor
the temperature of the device and its environment.
The ADM1032 communicates over a two-wire serial interface
compatible with System Management Bus (SMBus) standards.
Under and over temperature limits can be programmed into the
device over the serial bus, and an ALERT output signals when
the on-chip or remote temperature measurement is out of range.
This output can be used as an interrupt, or as an SMBus alert.
The THERM output is a comparator output that allows CPU
clock throttling or on/off control of a cooling fan.
ADM1032–SPECIFICATIONS(TA = TMIN to TMAX, VDD = VMIN to VMAX, unless otherwise noted.)OPEN-DRAIN DIGITAL OUTPUTS
(THERM, ALERT)
NOTESSee Table VI for information on other conversion rates.Guaranteed by Design, not production tested.The SMBus timeout is a programmable feature. By default it is not enabled. Details on how to enable it are available in the SMBus section of this data sheet.
Figure 1.Diagram for Serial Bus Timing
ORDERING GUIDE
PIN CONFIGURATION
PIN FUNCTION DESCRIPTIONS
ABSOLUTE MAXIMUM RATINGS*Positive Supply Voltage (VDD) to GND . . . . . . –0.3 V, +5.5 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to VDD + 0.3 V
D– to GND . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +0.6 V
SCLK, SDATA, ALERT . . . . . . . . . . . . . . . . –0.3 V to +5.5 V
THERM . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to VDD + 0.3 V
Input Current, SDATA, THERM . . . . . . . . . . . –1, +50 mA
Input Current, D– . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±1 mA
ESD Rating, All Pins (Human Body Model) . . . . . . >1000 V
Maximum Junction Temperature (TJ max) . . . . . . . . . 150°C
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
IR Reflow Peak Temp . . . . . . . . . . . . . . . . . . . . . . . . . 220°C
Lead Temp (Soldering 10 sec) . . . . . . . . . . . . . . . . . . . 300°C
*Stresses above those listed under Absolute Maximum Ratings may cause
permanent damage to the device. This is a stress rating only; functional operation
of the device at these or any other conditions above those indicated in the
operational section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
THERMAL CHARACTERISTICS8-Lead SO Package
θJA = 121°C/W
8-Lead Micro_SO Package
θJA = 142°C/W
ADM1032–Typical Performance Characteristics TPC 1. Temperature Error vs.
Leakage Resistance
TPC 4.Temperature Error vs. Power
Supply Noise Frequency
TPC 7.Temperature Error vs.
Common-Mode Noise Frequency
TPC 2.Temperature Error vs. Actual
Temperature Using 2N3906
TPC 5.Temperature Error vs.
Capacitance between D+ and D–
TPC 8.Standby Supply Current vs.
Clock Frequency
TPC 3.Temperature Error vs.
Differential Mode Noise Frequency
TPC 6.Operating Supply Current vs.
Conversion Rate
TPC 9.Standby Supply Current vs.
Supply Voltage
FUNCTIONAL DESCRIPTIONThe ADM1032 is a local and remote temperature sensor and
over-temperature alarm. When the ADM1032 is operating
normally, the on-board A-to-D converter operates in a free-
running mode. The analog input multiplexer alternately selects
either the on-chip temperature sensor to measure its local tem-
perature, or the remote temperature sensor. These signals are
digitized by the ADC and the results stored in the Local and
Remote Temperature Value Registers.
The measurement results are compared with local and remote,
high, low and THERM temperature limits, stored in nine on-
chip registers. Out-of-limit comparisons generate flags that are
stored in the Status Register, and one or more out-of limit results
will cause the ALERT output to pull low. Exceeding THERM
temperature limits cause the THERM output to assert low.
The limit registers can be programmed, and the device con-
trolled and configured, via the serial System Management Bus
(SMBus). The contents of any register can also be read back via
the SMBus.
Control and configuration functions consist of:Switching the device between normal operation and
standby mode.Masking or enabling the ALERT output.Selecting the conversion rate.
MEASUREMENT METHODA simple method of measuring temperature is to exploit the
negative temperature coefficient of a diode, or the base-emitter
voltage of a transistor, operated at constant current. Unfortu-
nately, this technique requires calibration to null out the effect
of the absolute value of VBE, which varies from device to device.
The technique used in the ADM1032 is to measure the change
in VBE when the device is operated at two different currents.
This is given by:
where:
K is Boltzmann’s constant (1.38 × 10–23).
q is charge on the electron (1.6 × 10–19 Coulombs).
T is absolute temperature in Kelvins.
N is ratio of the two currents.
nf is the ideality factor of the thermal diode.
The ADM1032 is trimmed for an ideality factor of 1.008.
Figure 2 shows the input signal conditioning used to measure
the output of an external temperature sensor. This figure shows
the external sensor as a substrate transistor, provided for tem-
perature monitoring on some microprocessors, but it could
equally well be a discrete transistor. If a discrete transistor is
used, the collector will not be grounded, and should be linked to
the base. To prevent ground noise interfering with the measure-
ment, the more negative terminal of the sensor is not referenced
to ground, but is biased above ground by an internal diode at
the D– input. If the sensor is operating in a noisy environment,
C1 may optionally be added as a noise filter. Its value is typi-
cally 2200 pF, but should be no more than 3000 pF. See the
section on Layout Considerations for more information on C1.
To measure ∆VBE, the sensor is switched between operating cur-
rents of I and N × I. The resulting waveform is passed through
a 65 kHz low-pass filter to remove noise, thence to a chopper-
stabilized amplifier that performs the functions of amplification
and rectification of the waveform to produce a dc voltage pro-
portional to ∆VBE. This voltage is measured by the ADC to give
a temperature output in two’s complement format. To further
reduce the effects of noise, digital filtering is performed by aver-
aging the results of 16 measurement cycles.
Signal conditioning and measurement of the internal tempera-
ture sensor is performed in a similar manner.
TEMPERATURE DATA FORMATOne LSB of the ADC corresponds to 0.125°C, so the ADC can
measure from 0°C to 127.875°C. The temperature data format
is shown in Tables I and II.
The results of the local and remote temperature measurements
are stored in the Local and Remote Temperature Value Registers,
and are compared with limits programmed into the Local and
Remote High and Low Limit Registers.
Table I.Temperature Data Format (Local Temperature and
Remote Temperature High Byte)
ADM1032
Status RegisterBit 7 of the Status Register indicates that the ADC is busy con-
verting when it is high. Bits 6 to 3, 1, and 0 are flags that indicate
the results of the limit comparisons. Bit 2 is set when the remote
sensor is open circuit.
If the local and/or remote temperature measurement is above the
corresponding high temperature limit, or below or equal to, the
corresponding low temperature limit, one or more of these flags
will be set. These five flags (Bits 6 to 2) NOR’d together, so that
if any of them is high, the ALERT interrupt latch will be set and
the ALERT output will go low. Reading the Status Register will
clear the five flag bits, provided the error conditions that caused
the flags to be set have gone away. While a limit comparator is
tripped due to a value register containing an out-of-limit measure-
ment, or the sensor is open circuit, the corresponding flag bit
cannot be reset. A flag bit can only be reset if the corresponding
value register contains an in-limit measurement or the sensor is good.
The ALERT interrupt latch is not reset by reading the Status
Register, but will be reset when the ALERT output has been
serviced by the master reading the device address, provided the
error condition has gone away and the Status Register flag bits
have been reset.
When Flags 1 and 0 are set, the THERM output goes low to
indicate that the temperature measurements are outside the
programmed limits. THERM output does not need to be reset,
unlike the ALERT output. Once the measurements are within the
limits, the corresponding Status register bits are reset and the
THERM output goes high.
Table IV. Status Register Bit Assignments*These flags stay high until the status register is read or they are reset by POR.
Configuration RegisterTwo bits of the Configuration Register are used. If Bit 6 is 0,
which is the power-on default, the device is in operating mode
with the ADC converting. If Bit 6 is set to 1, the device is in
standby mode and the ADC does not convert. The SMBus does,
however, remain active in Standby Mode so values can be read
from or written to the SMBus. The ALERT and THERM O/Ps
are also active in Standby Mode.
Bit 7 of the configuration register is used to mask the alert
output. If Bit 7 is 0, which is the power-on default, the output is
enabled. If Bit 7 is set to 1, the output is disabled.
Table II.Extended Temperature Resolution (Remote
Temperature Low Byte)
ADM1032 REGISTERSThe ADM1032 contains registers that are used to store the
results of remote and local temperature measurements, high and
low temperature limits, and to configure and control the device.
A description of these registers follows, and further details are
given in Tables III to VII.
Address Pointer RegisterThe Address Pointer Register itself does not have, or require, an
address, as it is the register to which the first data byte of every
Write operation is written automatically. This data byte is an
address pointer that sets up one of the other registers for the
second byte of the Write operation, or for a subsequent read
operation.
The power-on default value of the Address Pointer Register is
00h, so if a read operation is performed immediately after power-
on without first writing to the Address Pointer, the value of the
local temperature will be returned, since its register address is 00h.
Value RegistersThe ADM1032 has three registers to store the results of Local
and Remote temperature measurements. These registers are
written to by the ADC only and can be read over the SMBus.
Offset RegisterSeries resistance on the D+ and D– lines in processor packages
and clock noise can introduce offset errors into the remote tem-
perature measurement. To achieve the specified accuracy on
this channel these offsets must be removed.
The offset value is stored as an 11-bit, two’s complement value
in registers 11h (high byte) and 12h (low byte, left justified).
The value of the offset is negative if the MSB of register 11h is 1
and it is positive if the MSB of register 12h is 0. The value is
added to the measured value of remote temperature.
The offset register powers up with a default value of 0°C, and
will have no effect if nothing is written to them.
Table III.Sample Offset Register Codes
