Remote-Junction Temperature-Controlled
Fan-Speed Regulator with SMBus Interface
Pin Description
PIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
NAME
VFAN
V CC
DXP
DXN
FAN
ADD1
PGND
AGND
OVERT
ADD0
ALERT
SMBDATA
GAIN
SMBCLK
STBY
TACH IN
FUNCTION
Fan Drive Power-Supply Input. 4.5V to 13.5V.
Supply Voltage Input. +3V to +5.5V. Bypass V CC to ground with a 0.1μF capacitor.
Input: Remote-Junction Anode. Place a 2200pF capacitor between DXP and DXN for noise filtering.
Input: Remote-Junction Cathode. DXN is internally biased to a diode voltage above ground.
Open-Drain Output to Fan Low Side. Connect a minimum 1μF capacitor between FAN and VFAN.
SMBus Address Select Pin. ADD0 and ADD1 are sampled upon power-up.
Power Ground
Analog Ground
Overtemperature Shutdown Output. Active-low output (programmable for active high if desired). Open drain.
SMBus Slave Address Select Pin. ADD0 and ADD1 are sampled upon power-up.
SMBus Alert (Interrupt) Output. Open-drain, active-low output.
SMBus Serial Data Input/Output. Open drain.
Gain Control. Connect an external resistor from GAIN to V CC to reduce the gain of the current-sense mode.
SMBus Clock Line from Controller. This line tolerates inputs up to V CC even if MAX6660 is not powered.
Hardware Standby Input. Drive STBY low to reduce supply current. Temperature and comparison
data are retained in standby mode.
Fan Tachometer Input. Tolerates voltages up to VFAN.
Detailed Description
The MAX6660 is a remote temperature sensor and fan
controller with an SMBus interface. The MAX6660 con-
verts the temperature of a remote-junction temperature
sensor to a 10-bit + sign digital word. The remote tem-
perature sensor can be a diode-connected transistor,
such as a 2N3906, or the type normally found on the
substrate of many processors’ ICs. The temperature
information is provided to the fan-speed regulator and
is read over the SMBus interface. The temperature
data, through the SMBus, can be read as a 10-bit +
sign two’s complement word with a 0.125°C resolution
(LSB) and is updated every 0.25s.
The MAX6660 incorporates a closed-loop fan controller
that regulates fan speed with tachometer feedback. The
temperature information is compared to a threshold and
range setting, which enables the MAX6660 to automati-
cally set fan speed proportional to temperature. Full con-
trol of these modes is available, including being able to
open either the thermal control loop or the fan control
loop. Figure 1 shows a simplified block diagram.
ADC
The ADC is an averaging type that integrates over a
60ms period with excellent noise rejection. A bias cur-
rent is steered through the remote diode, where the for-
ward voltage is measured, and the temperature is com-
puted. The DXN pin is the cathode of the remote diode
and is biased at 0.65V above ground by an internal
diode to set up the ADC inputs for a differential mea-
surement. The worst-case DXP-DXN differential input
voltage range is 0.25V to 0.95V. Excess resistance in
series with the remote diode causes about +1/2°C error
per ohm. Likewise, 200mV of offset voltage forced on
DXP-DXN causes approximately 1°C error.
A/D Conversion Sequence
A conversion sequence is initiated every 250ms in the
free-running autoconvert mode (bit 6 = 0 in the
Configuration register) or immediately by writing a One-
Shot command. The result of the new measurement is
available after the end of conversion. The results of the
previous conversion sequence are still available when
the ADC is converting.
Remote-Diode Selection
Temperature accuracy depends on having a good-
quality, diode-connected small-signal transistor.
Accuracy has been experimentally verified for all
devices listed in Table 1. The MAX6660 can also direct-
_______________________________________________________________________________________
5
相关PDF资料
MAX6662EVKIT+ EVALUATION KIT FOR MAX6662
MAX6683EVKIT EVAL KIT FOR MAX6683
MAX6969EVKIT+ KIT EVAL FOR MAX6969
MAX7500EVKIT+ KIT EVAL FOR MAX7500
MAX8630XEVKIT+ KIT EVAL FOR MAX8630X MAX8630W
MAX8678EVKIT+ KIT EVAL FOR MAX8678
MAX9635EVKIT+ KIT EVAL FOR MAX9635
MB-1390-DG BRACKET EXTERNAL MOUNT DARK GRY
相关代理商/技术参数
MAX6660EVSYS 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
MAX6661AEE 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
MAX6661AEE+ 功能描述:板上安装温度传感器 Remote-Junction Fan-Speed Regulator 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
MAX6661AEE+T 功能描述:板上安装温度传感器 Remote-Junction Fan-Speed Regulator 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
MAX6661AEE-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
MAX6662EVKIT+ 功能描述:板上安装温度传感器 MAX6662 Eval Kit 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
MAX6662MSA 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
MAX6662MSA+ 功能描述:板上安装温度传感器 12-Bit + Sign Temperature Sensor 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