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| 型號(hào)： | ADM1027ARQZ-RL7 |
| 廠商： | ON Semiconductor |
| 文件頁數(shù)： | 20/56頁 |
| 文件大?。?/td> | 1822K |
| 描述： | IC REMOTE THERMAL CTLR 24QSOP |
| 產(chǎn)品變化通告： | MFG CHG Notification ADI to ON Semi Product Discontinuation Notice 25/Aug/2008 Product Obsolescence 30/Sept/2009 |
| 標(biāo)準(zhǔn)包裝： | 1,000 |
| 系列： | dBCool® |
| 功能： | 風(fēng)扇控制，溫度監(jiān)控器 |
| 傳感器類型： | 內(nèi)部和外部 |
| 感應(yīng)溫度： | 0°C ~ 105°C，外部傳感器 |
| 精確度： | ±1°C |
| 拓?fù)洌?/td> | ADC，比較器，風(fēng)扇速度計(jì)數(shù)器，多路復(fù)用器，寄存器庫 |
| 輸出類型： | SMBus? |
| 輸出警報(bào)： | 無 |
| 輸出風(fēng)扇： | 是 |
| 電源電壓： | 3 V ~ 5.5 V |
| 工作溫度： | 0°C ~ 105°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 24-SSOP（0.154"，3.90mm 寬） |
| 供應(yīng)商設(shè)備封裝： | 24-QSOP |
| 包裝： | 帶卷 (TR) |
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REV. A
20
ADM1027
FAN DRIVE CIRCUITRY
Fan Drive Using PWM Control
The ADM1027 uses Pulsewidth Modulation (PWM) to control
fan speed. This relies on varying the duty cycle (or on/off ratio)
of a square wave applied to the fan to vary the fan speed. The
external circuitry required to drive a fan using PWM control is
extremely simple. A single NMOSFET is the only drive device
required. The specifications of the MOSFET depend on the
maximum current required by the fan being driven. Typical
notebook fans draw a nominal 170 mA, so SOT devices can be
used where board space is a concern. In desktops, fans can
typically draw 250 mA to 300 mA each. If you drive several fans
in parallel from a single PWM output or drive larger server fans,
the MOSFET will need to handle the higher current require-
ments. The only other stipulation is that the MOSFET should
have a gate voltage drive, V
GS
< 3.3 V for direct interfacing to
the PWM_OUT pin. V
GS
can be greater than 3.3 V as long as
the pull-up on the gate is tied to 5 V. The MOSFET should
also have a low on resistance to ensure that there is not signifi-
cant voltage drop across the FET. This would reduce the
voltage applied across the fan and thus the maximum operating
speed of the fan.
Figure 18 shows how a 3-wire fan may be driven using PWM
control.
ADM1027
TACH/AIN
PWM
4.7k
10k
10k
10k
3.3V
12V
12V
12V
FAN
Q1
NDT3055L
Figure 18. Driving a 3-Wire Fan Using an
N-Channel MOSFET
Figure 18 uses a 10 kW pull-up resistor for the TACH signal.
This assumes that the TACH signal is open-collector from the
fan. In all cases, the TACH signal from the fan must be kept
below 5 V maximum to prevent damaging the ADM1027. If in
doubt as to whether the fan used has an open-collector or totem
pole TACH output, use one of the input signal conditioning
circuits shown in the Fan Speed Measurement section.
Figure 19 shows a fan drive circuit using an NPN transistor
such as a general-purpose MMBT2222. While these devices are
inexpensive, they tend to have much lower current handling
capabilities and higher on resistance than MOSFETs. When
choosing a transistor, care should be taken to ensure that it
meets the fans current requirements. Ensure that the base
resistor is chosen such that the transistor is saturated when the
fan is powered on.
ADM1027
TACH/AIN
PWM
4.7k
10k
10k
10k
3.3V
12V
12V
12V
FAN
Q1
MMBT2222
Figure 19. Driving a 3-Wire Fan Using an NPN Transistor
Rev. 3 | Page 20 of 56 | www.onsemi.com
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ADM1029ARQZ-R7 | IC SENSOR 2TEMP/FAN CTRL 24QSOP |
| ADM1030ARQZ-RL7 | IC SNSR TEMP/FAN PWM CTRL 16QSOP |
| ADM1032ARZ-REEL | IC TEMP MONITOR 85DEG 8SOIC |
| ADM1033ARQZ-RL7 | IC THERM/FAN SPEED CTLR 16-QSOP |
| ADM1034ARQZ-REEL | IC THERM/FAN SPEED CTRLR 16-QSOP |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ADM1027ARQZ-RL71 | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:dBCOOLa?￠ Remote Thermal Controller and Voltage Monitor |
| ADM1028 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Remote Thermal Diode Monitor with Linear Fan Control |
| ADM1028ARQ | 功能描述:IC SENSOR TEMP/FAN CTRL 16QSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 熱管理 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 功能:溫度監(jiān)控系統(tǒng)（傳感器） 傳感器類型:內(nèi)部和外部 感應(yīng)溫度:-40°C ~ 125°C，外部傳感器 精確度:±2.5°C 本地（最大值），±5°C 遠(yuǎn)程（最大值） 拓?fù)?ADC，比較器，寄存器庫 輸出類型:2 線 SMBus? 輸出警報(bào):無 輸出風(fēng)扇:無 電源電壓:2.7 V ~ 5.5 V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-8 供應(yīng)商設(shè)備封裝:SOT-23-8 包裝:Digi-Reel® 其它名稱:296-22675-6 |
| ADM1028ARQ-REEL7 | 制造商:Rochester Electronics LLC 功能描述:TDM + LINEAR FAN CONTROL I.C. - Tape and Reel |
| ADM1029 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Dual PWM Fan Controller and Temperature Monitor for High Availability Systems |
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