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| 型号： | ADM1026JST-REEL |
| 厂商： | ON Semiconductor |
| 文件页数： | 19/55页 |
| 文件大小： | 0K |
| 描述： | IC CNTRL SYS REF/EEPROM 48LQFP |
| 产品变化通告： | MFG CHG Notification ADI to ON Semi Product Obsolescence 30/Sept/2009 |
| 标准包装： | 2,000 |
| 功能： | 硬件监控器 |
| 传感器类型： | 内部和外部 |
| 感应温度： | 0°C ~ 100°C |
| 精确度： | ±3°C（最小值） |
| 拓扑： | ADC，比较器，多路复用器，寄存器库 |
| 输出类型： | SMBus? |
| 输出警报： | 无 |
| 输出风扇： | 是 |
| 电源电压： | 3 V ~ 5.5 V |
| 工作温度： | 0°C ~ 100°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 48-LQFP |
| 供应商设备封装： | 48-LQFP（7x7） |
| 包装： | 带卷 (TR) |
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ADM1026
If the V REF output is not being used, it should be left
unconnected. Do not connect V REF to GND using a
capacitor. The internal output buffer on the voltage reference
is capacitively loaded, which can cause the voltage reference
to oscillate. This affects temperature readings reported back
by the ADM1026. The recommended interface circuit for
the V REF output is shown in Figure 32.
by clearing Bit 3 of Configuration Register 1 (Address 00h)
to 0. If this bit is 1, then Pins 27 and 28 are A IN8 and A IN9 .
The forward voltage of a diode or diode-connected
transistor, operated at a constant current, exhibits a negative
temperature coefficient of about ? 2 mV/ ? C. Unfortunately,
the absolute value of V be varies from device to device, and
individual calibration is required to null this out, so the
technique is unsuitable for mass production.
D V be + K q T
ADM1026
V REF
24
10k ?
0.1 ? F
+12V
NDT3055
50 ?
0.1 ? F
10 ? F
V REF
The technique used in the ADM1026 is to measure the
change in V be when the device is operated at two different
currents, given by:
log n (N) (eq. 10)
where K is Boltzmann’s constant, q is the charge on the
carrier, T is the absolute temperature in Kelvins, and N is the
ratio of the two currents.
Figure 33 shows the input signal conditioning used to
measure the output of a remote temperature sensor. This
Figure 32. V REF Interface Circuit for V REF Loads > 2 mA
Temperature Measurement System
Local Temperature Measurement
The ADM1026 contains an on-chip band gap temperature
sensor whose output is digitized by the on-chip ADC. The
temperature data is stored in the local temperature value
register (Address 1Fh). As both positive and negative
temperatures can be measured, the temperature data is stored
in twos complement format, as shown in Table 8.
Theoretically, the temperature sensor and ADC can measure
temperatures from ? 128 ? C to +127 ? C with a resolution of
1 ? C. Temperatures below T MIN and above T MAX are outside
the operating temperature range of the device; however, so
local temperature measurements outside this range are not
possible. Temperature measurement from ? 128 ? C to
+127 ? C is possible using a remote sensor.
Remote Temperature Measurement
The ADM1026 can measure the temperature of two
remote diode sensors, or diode-connected transistors,
connected to Pins 25 and 26, or 27 and 28.
Pins 25 and 26 are a dedicated temperature input channel.
Pins 27 and 28 can be configured to measure a diode sensor
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 such as a 2N3904.
If a discrete transistor is used, the collector is not grounded
and should be linked to the base. If a PNP transistor is used,
the base is connected to the D ? input and the emitter to the
D+ input. If an NPN transistor is used, the emitter is
connected to the D ? input and the base to the D+ input.
To prevent ground noise from 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.
To measure D V be , the sensor is switched between
operating currents of I and N ? I. The resulting waveform is
passed through a 65 kHz low ? pass filter to remove noise,
and to a chopper-stabilized amplifier that performs the
functions of amplification and rectification of the waveform
to produce a DC voltage proportional to D V be . This voltage
is measured by the ADC to give a temperature output in
8-bit, twos complement format. To further reduce the effects
of noise, digital filtering is performed by averaging the
results of 16 measurement cycles. A remote temperature
measurement takes nominally 2.14 ms.
V DD
D+
I
N x I
I BIAS
V OUT+
REMOTE
SENSING
TRANSISTOR
C1*
D–
BIAS
DIODE
LOW ? PASS FILTER
f C = 65kHz
TO ADC
V OUT–
* CAPACITOR C1 IS OPTIONAL. IT IS ONLY NECESSARY IN NOISY ENVIRONMENTS.
C1 = 2.2nF TYPICAL, 3nF MAX.
Figure 33. Signal Conditioning for Remote Diode Temperature Sensors
http://onsemi.com
19
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ADM1026JST-REEL7 | 功能描述:IC CNTRL SYS REF/EEPROM 48LQFP 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 |
| ADM1026JSTZ | 功能描述:PMIC 解决方案 HI INT SYS MONITR IC RoHS:否 制造商:Texas Instruments 安装风格:SMD/SMT 封装 / 箱体:QFN-24 封装:Reel |
| ADM1026JSTZ-R7 | 功能描述:PMIC 解决方案 HI INT SYS MONITR IC RoHS:否 制造商:Texas Instruments 安装风格:SMD/SMT 封装 / 箱体:QFN-24 封装:Reel |
| ADM1026JSTZ-REEL | 功能描述:板上安装温度传感器 HI INT SYS MONITR IC RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor |
| ADM1026JSTZ-REEL7 | 制造商:Analog Devices 功能描述:IC SYSTEM MONITOR 制造商:ON Semiconductor 功能描述:IC SYSTEM MONITOR |
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