- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄165354 > ADT7462ACPZ-500RL7 (ON SEMICONDUCTOR) DIGITAL TEMP SENSOR-SERIAL, 8BIT(s), 4Cel, SQUARE, SURFACE MOUNT PDF資料下載
參數(shù)資料
| 型號(hào)： | ADT7462ACPZ-500RL7 |
| 廠商： | ON SEMICONDUCTOR |
| 元件分類： | 溫度/濕度傳感器 |
| 英文描述： | DIGITAL TEMP SENSOR-SERIAL, 8BIT(s), 4Cel, SQUARE, SURFACE MOUNT |
| 封裝： | 5 X 5 MM, LFCSP-32 |
| 文件頁(yè)數(shù)： | 27/88頁(yè) |
| 文件大?。?/td> | 836K |
| 代理商： | ADT7462ACPZ-500RL7 |
第1頁(yè)第2頁(yè)第3頁(yè)第4頁(yè)第5頁(yè)第6頁(yè)第7頁(yè)第8頁(yè)第9頁(yè)第10頁(yè)第11頁(yè)第12頁(yè)第13頁(yè)第14頁(yè)第15頁(yè)第16頁(yè)第17頁(yè)第18頁(yè)第19頁(yè)第20頁(yè)第21頁(yè)第22頁(yè)第23頁(yè)第24頁(yè)第25頁(yè)第26頁(yè)當(dāng)前第27頁(yè)第28頁(yè)第29頁(yè)第30頁(yè)第31頁(yè)第32頁(yè)第33頁(yè)第34頁(yè)第35頁(yè)第36頁(yè)第37頁(yè)第38頁(yè)第39頁(yè)第40頁(yè)第41頁(yè)第42頁(yè)第43頁(yè)第44頁(yè)第45頁(yè)第46頁(yè)第47頁(yè)第48頁(yè)第49頁(yè)第50頁(yè)第51頁(yè)第52頁(yè)第53頁(yè)第54頁(yè)第55頁(yè)第56頁(yè)第57頁(yè)第58頁(yè)第59頁(yè)第60頁(yè)第61頁(yè)第62頁(yè)第63頁(yè)第64頁(yè)第65頁(yè)第66頁(yè)第67頁(yè)第68頁(yè)第69頁(yè)第70頁(yè)第71頁(yè)第72頁(yè)第73頁(yè)第74頁(yè)第75頁(yè)第76頁(yè)第77頁(yè)第78頁(yè)第79頁(yè)第80頁(yè)第81頁(yè)第82頁(yè)第83頁(yè)第84頁(yè)第85頁(yè)第86頁(yè)第87頁(yè)第88頁(yè)
ADT7462
Rev. 2 | Page 33 of 88 | www.onsemi.com
FAN SPEED MEASUREMENT AND CONTROL
TACH INPUTS
Pin 1, Pin 2, Pin 3, Pin 4, Pin 7, Pin 8, Pin 21, and Pin 22 are
TACH inputs intended for fan speed measurement.
Signal conditioning in the ADT7462 accommodates the slow
rise and fall times typical of fan tachometer outputs. The maxi-
mum input signal range is 0 V to 5 V, even when VCC is less than
5 V. In the event that these inputs are supplied from fan outputs
that exceed 0 V to 5 V, either resistive attenuation of the fan
signal or diode clamping must be included to keep inputs
within an acceptable range.
Figure 44 to Figure 47 show circuits for most common fan
TACH circuits.
If the fan TACH output has a resistive pull-up to VCC, it can be
connected directly to the fan input, as shown in Figure 44.
12V
VCC
PULL-UP
4.7k
TYPICAL
TACH
OUTPUT
FAN SPEED
COUNTER
TACH
ADT7462
05
569
-034
Figure 44. Fan with TACH Pull-Up to VCC
If the fan output has a resistive pull-up to 12 V (or other voltage
greater than 5 V), the fan output can be clamped with a Zener
diode, as shown in Figure 45. The Zener diode voltage should
be chosen so that it is greater than VIH of the TACH input but
less than 5 V, allowing for the voltage tolerance of the Zener
diode. A value of between 3 V and 5 V is suitable.
12V
VCC
PULL-UP
4.7k
TYPICAL
TACH
OUTPUT
FAN SPEED
COUNTER
TACH
ADT7462
ZD1*
*CHOOSE ZD1 VOLTAGE APPROXIMATELY 0.8 × VCC.
0556
9-
03
5
Figure 45. Fan with TACH Pull-Up to Voltage > 5 V (Example, 12 V),
Clamped with Zener Diode
If the fan has a strong pull-up (less than 1 kΩ) to 12 V or a
totem-pole output, a series resistor can be added to limit the
Zener current, as shown in Figure 46. Alternatively, a resistive
attenuator can be used, as shown in Figure 47. R1 and R2
should be chosen such that
2 V < VPULL-UP × R2/(RPULL-UP + R1 + R2) < 5 V
The fan inputs have an input resistance of nominally 160 kΩ to
ground, so this should be taken into account when calculating
resistor values.
With a pull-up voltage of 12 V and a pull-up resistor of less than
1 kΩ, suitable values for R1 and R2 would be 100 kΩ and 47 kΩ.
This gives a high input voltage of 3.83 V.
5V OR 12V
VCC
PULL-UP TYP
<1k OR
TOTEM POLE
TACH
OUTPUT
FAN SPEED
COUNTER
TACH
ADT7462
ZD1
ZENER*
FAN
*CHOOSE ZD1 VOLTAGE APPROXIMATELY 0.8 × VCC.
R1
10k
0556
9-
036
Figure 46. Fan with Strong TACH Pull-Up to > VCC or Totem-Pole Output,
Clamped with a Zener Diode and Resistor
12V
VCC
<1k
TACH
OUTPUT
FAN SPEED
COUNTER
TACH
ADT7462
R2*
*SEE TEXT
R1*
0556
9-
037
Figure 47. Fan with Strong TACH Pull-Up to > VCC or Totem-Pole Output,
Attenuated with R1/R2
FAN SPEED MEASUREMENT
The method of fan speed measurement when using 3-wire fans
differs from that used with 4-wire fans. When 3-wire fans are in
use, power is continuously applied and removed from the fan,
thereby chopping the TACH information. As a result, every time
a fan speed measurement is to be made, the fan must be switched
on for a long enough period of time that a measurement can be
made. This is called pulse stretching. With 4-wire fans, power is
always applied to the fan, so fan speed measurements can be
made continuously, and there is no need for pulse stretching.
Pulse stretching is also not necessary when driving a 3-wire fan
with a dc input. The Fan Speed Measurement Without Pulse
Stretching section and the Fan Speed Measurement with Pulse
Stretching section describe how fan speed is measured both
when pulse stretching is required and when it is not.
Fan Speed Measurement Without Pulse Stretching
Fan speed is measured by the ADT7462, and the result is stored
in the fan TACH value registers. The fan counter does not count
the fan TACH output pulses directly because the fan speed can
be less than 1000 rpm, and it would take several seconds to
accumulate a reasonably large and accurate count. Instead, the
period of the fan revolution is measured by gating an on-chip
90 kHz oscillator into the input of a 16-bit counter for N periods of
the fan TACH output (see Figure 48), so the accumulated count
is actually proportional to the fan tachometer period and inversely
proportional to the fan speed.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ADTSM66SV | KEYPAD SWITCH, SPST, MOMENTARY-TACTILE, 0.05A, 12VDC, 3.92 N, SURFACE MOUNT-STRAIGHT |
| ADTS644N/KV | KEYPAD SWITCH, SPST, MOMENTARY-TACTILE, 0.05A, 12VDC, 1.57 N, THROUGH HOLE-STRAIGHT |
| ADTSM648N/KV | KEYPAD SWITCH, SPST, MOMENTARY-TACTILE, 0.05A, 12VDC, 1.57 N, SURFACE MOUNT-STRAIGHT |
| ADTS62KVB | KEYPAD SWITCH, SPST, MOMENTARY-TACTILE, 0.05A, 12VDC, 1.47 N, THROUGH HOLE-STRAIGHT |
| ADUC7022BCP | 32-BIT, FLASH, 45.5 MHz, RISC MICROCONTROLLER, QCC40 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ADT7462ACPZ-5RL7 | 功能描述:監(jiān)控電路 FLX H/WRE MON IC SRV RoHS:否 制造商:STMicroelectronics 監(jiān)測(cè)電壓數(shù): 監(jiān)測(cè)電壓: 欠電壓閾值: 過(guò)電壓閾值: 輸出類型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復(fù)位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel |
| ADT7462ACPZ-R7 | 功能描述:監(jiān)控電路 FLX H/WRE MON IC SRV RoHS:否 制造商:STMicroelectronics 監(jiān)測(cè)電壓數(shù): 監(jiān)測(cè)電壓: 欠電壓閾值: 過(guò)電壓閾值: 輸出類型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復(fù)位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel |
| ADT7462ACPZ-REEL | 功能描述:監(jiān)控電路 FLX H/WRE MON IC SRV RoHS:否 制造商:STMicroelectronics 監(jiān)測(cè)電壓數(shù): 監(jiān)測(cè)電壓: 欠電壓閾值: 過(guò)電壓閾值: 輸出類型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復(fù)位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel |
| ADT7462ACPZ-REEL7 | 功能描述:IC TEMP/VOLT MONITOR 32-LFCSP RoHS:是 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(kù) 輸出類型:2 線 SMBus? 輸出警報(bào):無(wú) 輸出風(fēng)扇:無(wú) 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 |
| ADT7462EBZEVB | 功能描述:EVALUATION BOARD ADT7462 制造商:on semiconductor 系列:* 零件狀態(tài):在售 標(biāo)準(zhǔn)包裝:1 |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。