ADM1032AR-REEL ,High Accuracy, Remote Thermal Diode Monitor in Micro SOIC PackageFEATURES PRODUCT DESCRIPTIONOn-Chip and Remote Temperature Sensing The ADM1032 is a dual-channel di ..
ADM1032AR-REEL ,High Accuracy, Remote Thermal Diode Monitor in Micro SOIC PackageFEATURES PRODUCT DESCRIPTIONOn-Chip and Remote Temperature Sensing The ADM1032 is a dual-channel di ..
ADM1032AR-REEL7 ,High Accuracy, Remote Thermal Diode Monitor in Micro SOIC Package1C Remote and LocalSystem Temperature Monitor*ADM1032
ADM1032ARZ , 1C Remote and Local System Temperature Monitor
ADM1032ARZ , 1C Remote and Local System Temperature Monitor
ADM1034 ,Thermal Monitor and Fan Speed ControllerAPPLICATIONS Programmable fault queue SMBusALERT output Desktop and notebook PCs Embedded systems F ..
AH175-WL-7-A , HALL EFFECT LATCH FOR HIGH TEMPERATURE
AH175-WL-7-B , HALL EFFECT LATCH FOR HIGH TEMPERATURE
AH180 , MICROPOWER OMNIPOLAR HALL-EFFECT SENSOR SWITCH
AH1801-FJG-7 , MICROPOWER, ULTRA-SENSITIVE HALL EFFECT
AH1801-FJG-7 , MICROPOWER, ULTRA-SENSITIVE HALL EFFECT
AH1801-SNG-7 , MICROPOWER, ULTRA-SENSITIVE HALL EFFECT
ADM1032AR-1-ADM1032ARM-1-ADM1032ARM-REEL-ADM1032ARM-REEL7-ADM1032ARMZ-ADM1032AR-REEL-ADM1032AR-REEL7
High Accuracy, Remote Thermal Diode Monitor in Micro SOIC Package
REV.D
�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 Under/Overtemperature Limits
Programmable Fault Queue
Overtemperature 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 SOIC and MSOP Packages
APPLICATIONS
Desktop and Notebook Computers
Smart Batteries
Industrial Controllers
Telecommunications Equipment
Instrumentation
Embedded Systems
PRODUCT DESCRIPTIONThe ADM1032 is a dual-channel digital thermometer and under/
overtemperature alarm intended for use in personal computers and
thermal management systems. The higher 1∞C accuracy offered
allows systems designers to safely reduce temperature guardband-
ing 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 tech-
nique cancels out the absolute value of the transistor’s base emitter
voltage so that no calibration is required. The second measurement
channel measures the output of an on-chip temperature sensor to
monitor the temperature of the device and its environment.
The ADM1032 communicates over a 2-wire serial interface
compatible with System Management Bus (SMBus) standards.
Under and overtemperature 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. An ADM1032-1
is available. The only difference between the ADM1032 and the
ADM1032-1 is the default value of the external THERM limit.
An ADM1032-2 is also available. It has a different SMBus address
to the ADM1032 and the ADM1032-1. The SMBus address of the
ADM1032-2 is 0x4D.
*Patents 5,982,221, 6,097,239, 6,133,753, 6,169,442, 5,867,012.
ADM1032–SPECIFICATIONSOPEN-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 Serial Bus Interface section of this data sheet.
Specifications subject to change without notice.
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 VTHERM . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to VDD + 0.3 V
Input Current, SDATA, THERM . . . . . . . . –1 mA, +50 mA
Input Current, D– . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±1 mA
ESD Rating, All Pins (Human Body Model) . . . . . . >1,000 V
Maximum Junction Temperature (TJ max) . . . . . . . . . 150∞C
Storage Temperature Range . . . . . . . . . . . . –65∞C to +150∞C
IR Reflow Peak Temperature . . . . . . . . . . . . . . . . . . . . 220∞C
IR Reflow Peak Temperature for Pb-Free . . . . . . . . . . 260∞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 SOIC PackageqJA = 121∞C/W
8-Lead MSOP PackageqJA = 142∞C/W
ORDERING GUIDEADM1032AR-REEL
ADM1032AR-REEL7
ADM1032ARZ
ADM1032AR-1REEL
ADM1032AR-1REEL7
ADM1032ARZ-1
ADM1032ARM-1REEL7
ADM1032ARMZ-1REEL7
ADM1032ARMZ-2Z = Pb-free part.
ADM1032
PIN CONFIGURATION
PIN FUNCTION DESCRIPTIONS2D+Positive Connection to Remote Temperature Sensor.
3D–Negative Connection to Remote Temperature Sensor.
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
ADM1032
FUNCTIONAL DESCRIPTIONThe ADM1032 is a local and remote temperature sensor and
overtemperature alarm. When the ADM1032 is operating
normally, the on-board A/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 are 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 causes 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 ofSwitching 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 the charge on the electron (1.6 ¥ 10–19 Coulombs).
T is the absolute temperature in Kelvins.
N is the 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
temperature 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 measurement,
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 typically
2,200 pF but should be no more than 3,000 pF. See the sec-
tion on Layout Considerations for more information on C1.
To measure DVBE, the sensor is switched between the operating
currents of I and N ¥ I. The resulting waveform is passed
through a 65 kHz low-pass filter to remove noise, and then to
a chopper-stabilized amplifier that performs the functions of
amplification and rectification of the waveform to produce a dc
voltage proportional to DVBE. This voltage is measured by the
ADC to give a temperature output in twos complement format.
To further reduce the effects of noise, digital filtering is performed
by averaging the results of 16 measurement cycles.
Signal conditioning and measurement of the internal temperature
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)
Status RegisterBit 7 of the Status Register indicates that the ADC is busy
converting 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 are 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 that the error conditions that
caused the flags to be set have gone away. While a limit compara-
tor is tripped due to a value register containing an out-of-limit
measurement, or the sensor is open circuit, the corresponding flag
bit cannot be reset. A flag bit can only be reset if the corre-
sponding 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 and 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, since 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
temperature measurement. To achieve the specified accuracy on
this channel, these offsets must be removed.
The offset value is stored as an 11-bit, twos 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 positive if the MSB of Register 12h is 0. The value is added
to the measured value of the 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
ADM1032
Consecutive ALERT RegisterThis value written to this register determines how many out-of-
limit measurements must occur before an ALERT is generated.
The default value is that one out-of-limit measurement generates
an ALERT. The max value that can be chosen is 4. The purpose
of this register is to allow the user to perform some filtering of the
output. This is particularly useful at the faster two conversion
rates where no averaging takes place.
Table VII. Consecutive ALERT Register CodesNOTES
x = Don’t care bit.
y = SMBus timeout bit. Default = 0. See SMBus section for more
information.
SERIAL BUS INTERFACEControl of the ADM1032 is carried out via the serial bus. The
ADM1032 is connected to this bus as a slave device, under the
control of a master device.
There is a programmable SMBus timeout. When this is enabled,
the SMBus will timeout after typically 25 ms of no activity. However,
this feature is not enabled by default. To enable it, set Bit 7
of the Consecutive Alert Register (Address = 22h).
The ADM1032 supports packet error checking (PEC) and its
use is optional. It is triggered by supplying the extra clock for the
PEC byte. The PEC byte is calculated using CRC-8. The frame
check sequence (FCS) conforms to CRC-8 by the polynomial
Consult the SMBus 1.1 specification for more information.
ADDRESSING THE DEVICEIn general, every SMBus device has a 7-bit device address (except
for some devices that have extended, 10-bit addresses). When
the master device sends a device address over the bus, the slave
device with that address will respond. The ADM1032 and the
ADM1032-1 are available with one SMBUS address, which is
Hex 4C (1001 100). The ADM1032-2 is also available with one
SMBUS address; however, that address is Hex 4D (1001 101).
The serial bus protocol operates as follows:The master initiates data transfer by establishing a START
condition, defined as a high-to-low transition on the serial
data line SDATA, while the serial clock line SCLK remains
high. This indicates that an address/data stream will follow.
All slave peripherals connected to the serial bus respond to
the START condition and shift in the next eight bits, consisting
of a 7-bit address (MSB first) plus an R/W bit, which determines
the direction of the data transfer, i.e., whether data will be
written to or read from the slave device.
Table V. Configuration Register Bit Assignments
Conversion Rate RegisterThe lowest four bits of this register are used to program the
conversion rate by dividing the internal oscillator clock by 1, 2,
4, 8, 16, 32, 64, 128, 256, 512, or 1,024 to give conversion
times from 15.5 ms (Code 0Ah) to 16 seconds (Code 00h).
This register can be written to and read back over the SMBus.
The higher four bits of this register are unused and must be set
to zero. Use of slower conversion times greatly reduces the
device power consumption, as shown in Table VI.
Table VI.Conversion Rate Register Codes
Limit RegistersThe ADM1032 has nine limit registers to store local and remote,
high, low, and THERM temperature limits. These registers can
be written to and read back over the SMBus.
The high limit registers perform a > comparison, while the low
limit registers perform a < comparison. For example, if the High
Limit Register is programmed with 80∞C, then measuring 81∞C
will result in an alarm condition. If the Low Limit Register is
programmed with 0∞C, measuring 0∞C or lower will result in an
alarm condition. Exceeding either the local or remote THERM
limit asserts THERM low. A default hysteresis value of 10∞C is
provided, which applies to both channels. This hysteresis may
be reprogrammed to any value after power up (Reg 0x21h).
One-Shot RegisterThe One-Shot Register is used to initiate a single conversion
and comparison cycle when the ADM1032 is in Standby Mode,
after which the device returns to standby. This is not a data
register as such, and it is the write operation that causes the
one-shot conversion. The data written to this address is irrel-
evant and is not stored. The conversion time on a single shot is
