REV. A
14
ADM1027
TEMPERATURE MEASUREMENT SYSTEM
Local Temperature Measurement
The ADM1027 contains an on-chip band gap temperature
sensor whose output is digitized by the on-chip 10-bit ADC.
The 8-bit MSB temperature data is stored in the local temp
register (Address 0x26). As both positive and negative tempera-
tures can be measured, the temperature data is stored in twos
complement format, as shown in Table III. Theoretically, the
temperature sensor and ADC can measure temperatures from
128
o
C to +127
o
C with a resolution of 0.25
o
C. However, this
exceeds the operating temperature range of the device (0
o
C to
105
o
C), so local temperature measurements outside this range
are not possible. Temperature measurement from 127
o
C to
+127
o
C is possible using a remote sensor.
Remote Temperature Measurement
The ADM1027 can measure the temperature of two remote
diode sensors or diode-connected transistors connected to
Pins 15 and 16, or 17 and 18.
The forward voltage of a diode or diode-connected transistor,
operated at a constant current, exhibits a negative temperature
coefficient of about 2 mV/
o
C. Unfortunately, the absolute
value of V
be
varies from device to device, and individual calibra-
tion is required to null this out, so the technique is unsuitable
for mass production. The technique used in the ADM1027 is to
measure the change in V
be
when the device is operated at two
different currents. This is given by
where:
K is Boltzmanns constant.
q is charge on the carrier.
T is absolute temperature in kelvins.
N is the ratio of the two currents.
Figure 13 shows the input signal conditioning used to measure
the output of a remote temperature sensor. This figure shows the
external sensor as a substrate transistor, provided for temperature
monitoring on some microprocessors. It could equally well be a
discrete transistor such as a 2N3904/06.
D+
D
REMOTE
SENSING
TRANSISTOR
I
N I
I
BIAS
V
DD
V
OUT+
TO ADC
V
OUT
BIAS
DIODE
LOW-PASS
FILTER
f
C
= 65kHz
THERMDA
THERMDC
CPU
Figure 13. Signal Conditioning for Remote Diode Temperature Sensors
DV
KT q
N
be
=
?/DIV>
( )
ln
Rev. 3 | Page 14 of 56 | www.onsemi.com
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
ADM1029ARQZ-R7
IC SENSOR 2TEMP/FAN CTRL 24QSOP
ADM1030ARQZ-RL7
IC SNSR TEMP/FAN PWM CTRL 16QSOP
ADM1032ARZ-REEL
IC TEMP MONITOR 85DEG 8SOIC
ADM1033ARQZ-RL7
IC THERM/FAN SPEED CTLR 16-QSOP
ADM1034ARQZ-REEL
IC THERM/FAN SPEED CTRLR 16-QSOP
ADN8810ACPZ-REEL7
IC CURRENT SOURCE(12BIT) 24LFCSP
ADP2140ACPZ3328R7
IC REG DL BCK/LINEAR 10LFCSP
ADP5022ACBZ-6-R7
IC REG TRPL BCK/LINEAR 16WLCSP
相关代理商/技术参数
ADM1027ARQZ-RL71
制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:dBCOOLa?￠ Remote Thermal Controller and Voltage Monitor
ADM1028
制造商:AD 制造商全称:Analog Devices 功能描述:Remote Thermal Diode Monitor with Linear Fan Control
ADM1028ARQ
功能描述:IC SENSOR TEMP/FAN CTRL 16QSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 热管理 系列:- 标准包装:1 系列:- 功能:温度监控系统（传感器） 传感器类型:内部和外部 感应温度:-40°C ~ 125°C，外部传感器 精确度:±2.5°C 本地（最大值），±5°C 远程（最大值） 拓扑:ADC，比较器，寄存器库 输出类型:2 线 SMBus? 输出警报:无 输出风扇:无 电源电压:2.7 V ~ 5.5 V 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:SOT-23-8 供应商设备封装:SOT-23-8 包装:Digi-Reel® 其它名称:296-22675-6
ADM1028ARQ-REEL7
制造商:Rochester Electronics LLC 功能描述:TDM + LINEAR FAN CONTROL I.C. - Tape and Reel
ADM1029
制造商:AD 制造商全称:Analog Devices 功能描述:Dual PWM Fan Controller and Temperature Monitor for High Availability Systems
ADM1029ARQ
制造商:Rochester Electronics LLC 功能描述:TDM AND FAN CONTROLLER I.C. - Bulk
ADM1029ARQ-REEL7
制造商:Rochester Electronics LLC 功能描述: 制造商:Analog Devices 功能描述:
ADM1029ARQZ
功能描述:马达/运动/点火控制器和驱动器 +/- 1 C Digital Serial RoHS:否 制造商:STMicroelectronics 产品:Stepper Motor Controllers / Drivers 类型:2 Phase Stepper Motor Driver 工作电源电压:8 V to 45 V 电源电流:0.5 mA 工作温度:- 25 C to + 125 C 安装风格:SMD/SMT 封装 / 箱体:HTSSOP-28 封装:Tube