收藏本站
ADT7468
ANALOG-TO-DIGITAL CONVERTER
All analog inputs are multiplexed into the on-chip, successive
approximation, analog-to-digital converter, which has a resolu-
tion of 10 bits. The basic input range is 0 V to 2.25 V, but the
inputs have built-in attenuators to allow measurement of 2.5 V,
3.3 V, 5 V, 12 V, and the processor core voltage V CCP without any
external components. To allow for the tolerance of these supply
voltages, the ADC produces an output of 3/4 full scale (decimal
768 or 300 hex) for the nominal input voltage and therefore has
adequate headroom to cope with overvoltages.
VOLTAGE MEASUREMENT INPUT
The ADT7468 has four external voltage measurement channels
and can measure its own supply voltage, V CC . Pins 20 to 23 can
measure 5 V, 12 V, 2.5 V supplies, and the processor core voltage
V CCP (0 V to 3 V input). The V CC supply voltage measurement is
carried out through the V CC pin (Pin 4). Setting Bit 7 of Config-
uration Register 1 (Reg. 0x40) allows a 5 V supply to power the
ADT7468 and be measured without overranging the V CC
measurement channel. The 2.5 V input can be used to monitor a
chipset supply voltage in computer systems.
Input Circuitry
The internal structure for the analog inputs is shown in
Figure 22. The input circuit consists of an input protection
diode, an attenuator, and a capacitor to form a first-order low-
pass filter that gives input immunity to high frequency noise.
120k ?
12V IN
20k ? 30pF
Reg. 0x24, 12 V reading = 0x00 default
Voltage Limit Registers
Associated with each voltage measurement channel is a high
and low limit register. Exceeding the programmed high or low
limit causes the appropriate status bit to be set. Exceeding either
limit can also generate SMBALERT interrupts.
Reg. 0x44, 2.5 V low limit = 0x00 default
Reg. 0x45, 2.5 V high limit = 0xFF default
Reg. 0x46, V CCP low limit = 0x00 default
Reg. 0x47, V CCP high limit = 0xFF default
Reg. 0x48, V CC low limit = 0x00 default
Reg. 0x49, V CC high limit = 0xFF default
Reg. 0x4A, 5 V low limit = 0x00 default
Reg. 0x4B, 5 V high limit = 0xFF default
Reg. 0x4C, 12 V Low Limit = 0x00 default
Reg. 0x4D, 12 V High Limit = 0xFF default
Table 6 shows the input ranges of the analog inputs and output
codes of the 10-bit ADC.
When the ADC is running, it samples and converts a voltage
input in 0.7 ms and averages 16 conversions to reduce noise; a
5V IN
93k ?
47k ?
30pF
measurement takes nominally 11 ms.
ADDITIONAL ADC FUNCTIONS FOR VOLTAGE
3.3V IN
68k ?
71k ?
30pF
MUX
MEASUREMENTS
A number of other functions are available on the ADT7468 to
offer the system designer increased flexibility.
2.5V IN
45k ?
Turn-Off Averaging
94k ?
30pF
For each voltage measurement read from a value register,
V CCP
17.5k ?
16 readings have actually been made internally and the results
averaged before being placed into the value register. For
52.5k ?
35pF
instance, where faster conversions are needed, setting Bit 4 of
Configuration Register 2 (Reg. 0x73) turns averaging off. This
Figure 22. Structure of Analog Inputs
Voltage Measurement Registers
Reg. 0x20, 2.5 V reading = 0x00 default
Reg. 0x21, V CCP reading = 0x00 default
Reg. 0x22, V CC reading = 0x00 default
Reg. 0x23, 5 V reading = 0x00 default
effectively gives a reading 16 times faster (0.7 ms), but the
reading may be noisier.
Bypass Voltage Input Attenuator
Setting Bit 5 of Configuration Register 2 (Reg. 0x73) removes
the attenuation circuitry from the 2.5 V, V CCP , V CC , 5 V, and 12 V
inputs, which allows the user to directly connect external
sensors or rescale the analog voltage measurement inputs for
other applications. The input range of the ADC without the
attenuators is 0 V to 2.25 V.
Rev. 3 | Page 16 of 81 | www.onsemi.com
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
ADT7473ZEVB BOARD EVALUATION FOR ADT7473
ADT7475EBZEVB BOARD EVALUATION FOR ADT7475
ADT7476EBZEVB BOARD EVALUATION FOR ADT7476
ADT7490ZEVB BOARD EVALUATION FOR ADT7490
ADZS-21262-1-EZEXT BOARD DAUGHTER FOR ADSP-21262
ADZS-BF-EZEXT-1 BOARD DAUGHTER ADSP-BF533/561KIT
ADZS-BFAV-EZEXT BOARD DAUGHT ADSP-BF533,37,61KIT
ADZS-BFSHUSB-EZEXT BOARD DAUGHTER EZ EXTENDER
相关代理商/技术参数
ADT7470 制造商:AD 制造商全称:Analog Devices 功能描述:Temperature Sensor Hub and Fan Controller
ADT7470_13 制造商:AD 制造商全称:Analog Devices 功能描述:Temperature Sensor Hub and Fan Controller
ADT7470ARQ 制造商:Analog Devices 功能描述:Temp Sensor Digital Serial (I2C) 16-Pin QSOP
ADT7470ARQ-REEL 制造商:Rochester Electronics LLC 功能描述: 制造商:Analog Devices 功能描述:
ADT7470ARQ-REEL7 制造商:Analog Devices 功能描述:Temp Sensor Digital Serial (I2C) 16-Pin QSOP T/R
ADT7470ARQZ 功能描述:IC SENSOR TEMP FAN CTRLR 16QSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 热管理 系列:- 标准包装:3,000 系列:- 功能:温度开关 传感器类型:内部 感应温度:85°C 分界点 精确度:±6°C（最小值） 拓扑:ADC（三角积分型），比较器，寄存器库 输出类型:开路漏极 输出警报:是 输出风扇:是 电源电压:2.7 V ~ 5.5 V 工作温度:-55°C ~ 125°C 安装类型:表面贴装 封装/外壳:SC-74A，SOT-753 供应商设备封装:SOT-23-5 包装:带卷 (TR) 其它名称:ADT6501SRJZP085RL7-ND
ADT7470ARQZ-REEL 功能描述:IC SENSOR TEMP FAN CTRLR 16QSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 热管理 系列:- 标准包装:2,500 系列:SilentSense™ 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:-55°C ~ 125°C，外部传感器 精确度:±2°C 本地（最大），±3°C 远程（最大） 拓扑:ADC（三角积分型），比较器，寄存器库 输出类型:I²C?/SMBus? 输出警报:是 输出风扇:是 电源电压:2.7 V ~ 5.5 V 工作温度:-55°C ~ 125°C 安装类型:表面贴装 封装/外壳:8-TSSOP，8-MSOP（0.118"，3.00mm 宽） 供应商设备封装:8-MSOP 包装:带卷 (TR) 其它名称:MIC284-2BMMTRMIC284-2BMMTR-ND
ADT7470ARQZ-REEL7 功能描述:IC SENSOR TEMP FAN CTRLR 16QSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 热管理 系列:- 标准包装:2,500 系列:SilentSense™ 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:-55°C ~ 125°C，外部传感器 精确度:±2°C 本地（最大），±3°C 远程（最大） 拓扑:ADC（三角积分型），比较器，寄存器库 输出类型:I²C?/SMBus? 输出警报:是 输出风扇:是 电源电压:2.7 V ~ 5.5 V 工作温度:-55°C ~ 125°C 安装类型:表面贴装 封装/外壳:8-TSSOP，8-MSOP（0.118"，3.00mm 宽） 供应商设备封装:8-MSOP 包装:带卷 (TR) 其它名称:MIC284-2BMMTRMIC284-2BMMTR-ND