(POR) state. See Tables 37 for all other register functions
and the Register Descriptions section.
Temperature Measurements
The averaging ADC integrates over a 120ms period
(each channel, typically), with excellent noise rejection.
For internal temperature measurements, the ADC and
associated circuitry measure the forward voltage of the
internal sensing diode at low- and high-current levels
and compute the temperature based on this voltage.
For thermistor measurements, the reference voltage
and the thermistor voltage are measured and offset is
applied to yield a value that correlates well to thermistor
temperature within a wide temperature range. Both
channels are automatically converted once the conver-
sion process has started. If one of the two channels is
not used, the circuit still performs both measurements,
and the data from the unused channel may be ignored.
If either of the measured temperature values is below
0? the value in the corresponding temperature register
is clipped to zero when a negative offset is pro-
grammed into the thermistor offset register (17h).
Local (internal) temperature data is expressed directly
in degrees Celsius. Two registers contain the tempera-
ture data for the local channel. The high-byte register
has an MSB of 128癈 and an LSB of 1癈. The low- byte
register contains 3 bits, with an MSB of 0.5癈 and an
LSB of 0.125癈. The data format is shown in Table 1.
Thermistors allow measurements of external tempera-
tures. Connect a thermistor in series with a resistor,
R
EXT
. The thermistor should be connected between the
TH_ input and ground, and R
EXT
should be connected
between the reference output, REF, and the TH_ input,
as shown in the Typical Application Circuit.
The voltage across R
EXT
is measured by the ADC,
resulting in a value that is directly related to tempera-
Dual-Channel Temperature Monitors and
Fan-Speed Controllers with Thermistor Inputs
_______________________________________________________________________________________   7
SMBCLK
A = START CONDITION
B = MSB OF ADDRESS CLOCKED INTO SLAVE
C = LSB OF ADDRESS CLOCKED INTO SLAVE
D = R/W BIT CLOCKED INTO SLAVE
A
B
C
D
E    F
G
H
I
J
SMBDATA
t
SU:STA
t
HD:STA
t
LOW
t
HIGH
t
SU:DAT
t
SU:STO
t
BUF
L
M
K
E = SLAVE PULLS SMBDATA LINE LOW
F = ACKNOWLEDGE BIT CLOCKED INTO MASTER
G = MSB OF DATA CLOCKED INTO SLAVE
H = LSB OF DATA CLOCKED INTO SLAVE
I = MASTER PULLS DATA LINE LOW
J = ACKNOWLEDGE CLOCKED INTO SLAVE
K = ACKNOWLEDGE CLOCK PULSE
L = STOP CONDITION
M = NEW START CONDITION
Figure 2. SMBus Write Timing Diagram
SMBCLK
A
B
C
D
E   F
G
H
I   J  K
SMBDATA
t
SU:STA
t
HD:STA
t
LOW
t
HIGH
t
SU:DAT
t
HD:DAT
t
SU:STO
t
BUF
A = START CONDITION
B = MSB OF ADDRESS CLOCKED INTO SLAVE
C = LSB OF ADDRESS CLOCKED INTO SLAVE
D = R/W BIT CLOCKED INTO SLAVE
E = SLAVE PULLS SMBDATA LINE LOW
L
M
F = ACKNOWLEDGE BIT CLOCKED INTO MASTER
G = MSB OF DATA CLOCKED INTO MASTER
H = LSB OF DATA CLOCKED INTO MASTER
I = MASTER PULLS DATA LINE LOW
J = ACKNOWLEDGE CLOCKED INTO SLAVE
K = ACKNOWLEDGE CLOCK PULSE
L = STOP CONDITION
M = NEW START CONDITION
Figure 3. SMBus Read Timing Diagram
相关PDF资料
MAX6622UE9A+T IC PREC TEMP MONITOR 5CH 16TSSOP
MAX6626RMTT+T IC TEMP SENSOR I2C 6-TDFN
MAX6627MKA#TG16 IC TEMP SENSOR DGTL SOT23-8
MAX6636UP9A+T IC PREC TEMP MONITOR 7CH 20TSSOP
MAX6639FATE+ IC 2CH TEMP MONITOR 16TQFN
MAX6641AUB92+ IC TEMP MONITOR SMBUS 10UMAX
MAX6642ATT94+T IC TEMP SENSOR SMBUS 6TDFN
MAX6643LBFAEE+ IC CTLR PWM FAN-SPEED 16QSOP
相关代理商/技术参数
MAX6616AEG-T 功能描述:板上安装温度传感器 Dual Ch Temperature Monitor 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
MAX6616EVKIT 制造商:Maxim Integrated Products 功能描述:DUAL-CHANNEL TEMP MONITOR & FAN-SPE - Rail/Tube
MAX6618AUB+ 功能描述:接口 - 专用 PECI-to-I2C Translator RoHS:否 制造商:Texas Instruments 产品类型:1080p60 Image Sensor Receiver 工作电源电压:1.8 V 电源电流:89 mA 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:BGA-59
MAX6618AUB+G126 功能描述:接口 - 专用 PECI-to-I2C Translator RoHS:否 制造商:Texas Instruments 产品类型:1080p60 Image Sensor Receiver 工作电源电压:1.8 V 电源电流:89 mA 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:BGA-59
MAX6618AUB+T 功能描述:接口 - 专用 PECI-to-I2C Translator RoHS:否 制造商:Texas Instruments 产品类型:1080p60 Image Sensor Receiver 工作电源电压:1.8 V 电源电流:89 mA 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:BGA-59
MAX6618AUB+TG11 功能描述:接口 - 专用 PECI-to-I2C Translator RoHS:否 制造商:Texas Instruments 产品类型:1080p60 Image Sensor Receiver 工作电源电压:1.8 V 电源电流:89 mA 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:BGA-59
MAX6618AUB+TG126 功能描述:接口 - 专用 PECI-to-I2C Translator RoHS:否 制造商:Texas Instruments 产品类型:1080p60 Image Sensor Receiver 工作电源电压:1.8 V 电源电流:89 mA 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:BGA-59
MAX6620ATI+ 功能描述:马达/运动/点火控制器和驱动器 Quad Linear Fan Speed Controller 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