收藏本站
NCT7491
http://onsemi.com
36
Voltage Measurement Selection
The user can select which voltage channels to include in
the monitoring loop. By only including the channels that are
required the loop monitoring time can be reduced.
" Setting <2> of register 0x11 includes the V
TT
 channel
in the monitoring loop.
" Setting <3> of register 0x13 includes the 12V channel
in the monitoring loop.
" Setting <4> of register 0x13 includes the 5 V channel in
the monitoring loop.
" Setting <5> of register 0x13 includes the Vccp channel
in the monitoring loop.
" Setting <6> of register 0x13 includes the 2.5 V channel
in the monitoring loop.
" Setting <7> of register 0x13 includes the Vcc channel
in the monitoring loop.
Voltage Measurement Resolution
The NCT7491 uses a reference voltage of 2 V. The ADC
is 10bit giving a resolution of 1.953 mV per lsb. This is the
resolution that applies when the attenuators are disabled.
With attenuators enabled the resolution for each channel is
as follows:
" 12 V resolution = 15.92 mV per lsb
" 5 V resolution = 6.54 mV per lsb
" 2.5 V resolution = 3.26 mV per lsb
" Vccp resolution = 2.93 mV per lsb
" Vcc resolution = 4.29 mV per lsb
" V
TT
  resolution = 2.2 mV per lsb
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. 0x84, V
TT
 Low Limit
" Reg. 0x86, V
TT
 High Limit
" Reg. 0x44, 2.5 V Low Limit
" Reg. 0x45, 2.5 V High Limit
" Reg. 0x46, V
CCP
 Low Limit
" Reg. 0x47, V
CCP
 High Limit
" Reg. 0x48, V
CC
 Low Limit
" Reg. 0x49, V
CC
 High Limit
" Reg. 0x4A, 5 V Low Limit
" Reg. 0x4B, 5 V High Limit
" Reg. 0x4C, 12 V Low Limit
" Reg. 0x4D, 12 V High Limit 
Additional ADC Functions for Voltage Measurements
A number of other functions are available on the
NCT7491 to offer the system designer increased flexibility.
The functions described below are enabled by setting the
appropriate bit in configuration register 2 (0x73).
TurnOff Voltage Averaging
The averager length that is applied to the temperature
readings is also applied to the voltage readings. The averager
length is programmable as 4, 8, 16 or 32 samples. These
values can be selected in register 0x40 bits <7:6>.
When faster conversions are needed, setting Bit 3 of
Configuration Register 2 (Reg. 0x73) turns voltage
averaging off. This gives a faster reading, but the reading
can be noisier. The default roundrobin cycle time takes
TBD ms.
Bypass Individual Voltage Input Attenuators
Bits <7:3> of Configuration Register 4 (0x7D) can be
used to bypass individual voltage channel attenuators.
Table 30. BYPASSING VOLTAGE ATTENUATORS
Configuration Register 4 (0x7D)
Bit
Channel Attenuated
3
Bypass V
TT
 attenuator
4
Bypass 2.5 V attenuator
5
Bypass V
CCP
 attenuator
6
Bypass 5 V attenuator
7
Bypass 12 V attenuator
The input range of the ADC without the attenuators is 0 V
to 2 V.
GPIO Functions
There are up to 3 pins that can be configured as opendrain
general purpose digital I/O pins. These are pins 5 (GPIO1),
6 (GPIO2) and 19 (GPIO3) on the QSOP package and pins
2 (GPIO1), 3 (GPIO2) and 16 (GPIO3) on the QFN package.
GPIO1 and GPIO2 are shared with the SMBus Master Port
pins SCL_M and SDA_M. GPIO3 is shared with THERM
and SMBALERT functions.
There are 2 bits that must be programmed to enable the
GPIO1 and GPIO2 functions:
" Setting bit 1 of register 0x80 to 1 enables GPIO1 and
GPIO2
" Clearing bit 0 of register 0xB5 to 0 disables the SMBus
Master Port. This bit has priority over the GPIO enable
bit so must be cleared for GPIOs to function.
GPIO3 is enabled by setting bits <3:2> of register 0x7C to
<10>.
Each GPIO pin has associated direction, polarity and data
bits.
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
NCT75MNR2G IC SENSOR TEMP DGTL 8DFN
NCV8881PWR2G IC REG TRPL BUCK/LINEAR 16SOIC
NE1617ADS,112 IC TEMP MONITOR 16SSOP
NE1619DS,118 IC TEMP MONITOR 16SSOP
NIS5112D1R2G IC ELECTRONIC FUSE HOTSWAP 8SOIC
NIS5132MN2TXG IC ELECTRONIC FUSE 12V 10DFN
NIS5132MN3TXG IC ELECTRONIC FUSE 12V 10-DFN
NSI45015WT1G IC LED DRIVER LINEAR SOD-123
相关代理商/技术参数
NCT75DMR2G 功能描述:板上安装温度传感器 2-Channel Digital Thermometer w/ Alarm 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
NCT75DR2G 功能描述:板上安装温度传感器 2-Channel Digital Thermometer w/ Alarm 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
NCT75MNR2G 功能描述:板上安装温度传感器 HAS2MONOJLCC84SPACE 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
NCT7717U TR 制造商:Nuvoton Technology Corp 功能描述:SMBUS INTERFACE TEMP. SENSOR W 制造商:Nuvoton Technology Corp 功能描述:IC SMBUS TEMP SENSOR 8MSOP
NCT7718W TR 制造商:Nuvoton Technology Corp 功能描述:IC SMBUS TEMP SENSOR 8MSOP
NCT7802Y 制造商:Nuvoton Technology Corp 功能描述:
NCT7904D 制造商:Nuvoton Technology Corp 功能描述:IC H/W MONITOR
NCT80DBR2G 功能描述:板上安装温度传感器 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