参数资料
型号: MAX6643LBBAEE+T
厂商: Maxim Integrated
文件页数: 5/17页
文件大小: 208K
描述: IC CNTRLR FAN SPEED 16-QSOP
产品培训模块: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
标准包装: 2,500
功能: 风扇控制,温度监控器
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: ±3.5°C 本地(最大),±3°C 远程(最大)
拓扑: ADC,PWM 发生器,转速计计数器
输出类型: PWM
输出警报:
输出风扇:
电源电压: 3 V ~ 5.5 V
工作温度: -40°C ~ 125°C
安装类型: 表面贴装
封装/外壳: 16-SSOP(0.154",3.90mm 宽)
供应商设备封装: 16-QSOP
包装: 带卷 (TR)
Detailed Description
The MAX6643/MAX6644/MAX6645 measure temperature
and automatically adjust fan speed to ensure optimum
cooling while minimizing acoustic noise from the fan.
The MAX6643/MAX6644/MAX6645 generate a PWM
waveform that drives an external power transistor,
which in turn modulates the fans power supply. The
MAX6643/MAX6644/MAX6645 monitor temperature and
adjust the duty cycle of the PWM output waveform to
control the fans speed according to the cooling needs
of the system. The MAX6643 monitors its own die tem-
perature and an optional external transistors tempera-
ture, while the MAX6644 and MAX6645 each monitor
the temperatures of one or two external diode-connect-
ed transistors.
Temperature Sensor
The pn junction-based temperature sensor can mea-
sure temperatures up to two pn junctions. The
MAX6643 measures the temperature of an external
diode-connected transistor, as well as its internal tem-
perature. The MAX6644 and MAX6645 measure the
temperature of two external diode-connected transis-
tors. The temperature is measured at a rate of 1Hz.
If an external diode pin is shorted to ground or left
unconnected, the temperature is read as 0癈. Since the
larger of the two temperatures prevails, a faulty or
unconnected diode is not used for calculating fan
speed or determining overtemperature faults.
PWM Output
The larger of the two measured temperatures is always
used for fan control. The temperature is compared to
three thresholds: the high-temperature threshold (T
HIGH
),
the low-temperature threshold (T
LOW
), and the overtem-
perature threshold, OT. The OT comparison is done once
per second, whereas the comparisons with fan-control
thresholds T
HIGH
and T
LOW
are done once every 4s.
The duty-cycle variation of PWM_OUT from 0% to 100%
is divided into 64 steps. If the temperature measured
exceeds the threshold T
HIGH
, the PWM_OUT duty cycle
is incremented by one step, i.e., approximately 1.5%
(100/64). Similarly, if the temperature measured is below
the threshold T
LOW
, the duty cycle is decremented by
one step (1.5%). Since the T
HIGH
and T
LOW
compar-
isons are done only once every 4s, the maximum rate of
change of duty cycle is 0.4% per second.
Tables 1 and 2 show the 癈 value assigned to the TH_
and TL_ input combinations.
Automatic PWM Fan-Speed Controllers with
Overtemperature Output
_______________________________________________________________________________________   5
Pin Description (continued)
PIN
MAX6643
MAX6644
MAX6645
NAME
FUNCTION
12
12
9
PWM_OUT
PWM Output for Driving External Power Transistor. Connect to
the gate of an n-channel MOSFET or to the base of an npn.
PWM_OUT requires a pullup resistor. The pullup resistor can
be connected to a supply voltage as high as 5.5V, regardless
of the supply voltage.
13, 14
13, 14

OT2, OT1
Overtemperature Threshold Inputs. Connect to V
DD
, GND, or
leave unconnected to select the upper-limit OT fault output trip
temperature, in 5癈 increments. See Table 4.
16
16
10
V
DD
Power-Supply Input. 3.3V nominal. Bypass V
DD
 to GND with a
0.1礔 capacitor.
TH2
TH1
T
HIGH
 (癈)
L SUFFIX
T
HIGH
 (癈)
H SUFFIX
0
0
20
40
0
High-Z
25
45
0
1
30
50
High-Z
0
35
55
High-Z
High-Z
40
60
High-Z
1
45
65
1
0
50
70
1
High-Z
55
75
1
1
60
80
Table 1. Setting T
HIGH
(MAX6643 and MAX6644)
High-Z = High impedance.
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MAX6643LBEVKIT 功能描述:板上安装温度传感器 Evaluation Kit for the MAX6643/MAX6644 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
MAX6643LBFAEE 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
MAX6643LBFAEE+ 功能描述:马达/运动/点火控制器和驱动器 Automatic PWM 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
MAX6643LBFAEE+T 功能描述:马达/运动/点火控制器和驱动器 Automatic PWM 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
MAX6643LBFAEE-T 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