- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄383607 > MIC281-0BM6 (MICREL INC) Low-Cost IttyBitty Thermal Sensor IttyBitty PDF資料下載
參數(shù)資料
| 型號： | MIC281-0BM6 |
| 廠商： | MICREL INC |
| 元件分類： | 模擬信號調(diào)理 |
| 英文描述： | Low-Cost IttyBitty Thermal Sensor IttyBitty |
| 中文描述： | SPECIALTY ANALOG CIRCUIT, PDSO6 |
| 封裝： | SOT-23, 6 PIN |
| 文件頁數(shù)： | 10/12頁 |
| 文件大小： | 171K |
| 代理商： | MIC281-0BM6 |
MIC281
Application Information
Remote Diode Selection
Most small-signal PNP transistors with characteristics similar
to the JEDEC 2N3906 will perform well as remote temperature
sensors. Table 4 lists several examples of such parts that
Micrel has tested for use with the MIC281. Other transistors
equivalent to these should also work well.
Vendor
Part Number
Fairchild Semiconductor
MMBT3906
On Semiconductor
MMBT3906L
Infineon Technologies
SMBT3906
Samsung Semiconductor
KST3906-TF
Table 4. Transistors Suitable for Use as Remote
Diodes
Micrel
MIC281
10
November 2004
Package
SOT-23
SOT-23
SOT-23
SOT-23
Minimizing Errors
Self-Heating
One concern when using a part with the temperature accuracy
and resolution of the MIC281 is to avoid errors induced by
self-heating (V
DD
×
I
DD
) + (V
OL
×
I
OL
). In order to understand
what level of error this might represent, and how to reduce
that error, the dissipation in the MIC281 must be calculated
and its effects reduced to a temperature offset. The worst-
case operating condition for the MIC281 is when V
DD
=
3.6V. The maximum power dissipated in the part is given in
Equation 1 below.
In most applications, the DATA pin will have a duty cycle of
substantially below 25% in the low state. These considerations,
combined with more typical device and application parameters,
give a better system-level view of device self-heating. This
is illustrated by Equation 2. In any application, the best ap-
proach is to verify performance against calculation in the final
application environment. This is especially true when dealing
with systems for which some temperature data may be poorly
defined or unobtainable except by empirical means.
P
D
= [(I
DD
×
V
DD
)+(I
OL(DATA)
×
V
OL(DATA)
)]
P
D
= [(0.4mA
×
3.6V)+(6mA
×
0.5V)]
P
D
= 4.44mW
R
θ
(J-A)
of SOT23-6 package is 230°C/W, therefore...
the theoretical maximum self-heating is:
4.44mW
×
230°C/W = 1.02°C
Equation 1. Worst-Case Self-Heating
P
D
= [(I
DD
×
V
DD
)+(I
OL(DATA)
×
V
OL(DATA)
)]
P
D
= [(0.23mA
×
3.3V)+(25%
×
1.5mA
×
0.15V)]
P
D
= 0.815mW
R
θ
(J-A)
of SOT23-6 package is 230°C/W, therefore...
the typical self-heating is:
0.815mW
×
230°C/W = 0.188°C
Equation 2. Real-World Self-Heating Example
Series Resistance
The operation of the MIC281 depends upon sensing the
V
CB-E
of a diode-connected PNP transistor (“diode “) at two dif-
ferent current levels. For remote temperature measurements,
this is done using an external diode connected between T1
and ground. Since this technique relies upon measuring the
relatively small voltage difference resulting from two levels of
current through the external diode, any resistance in series
with the external diode will cause an error in the temperature
reading from the MIC281. A good rule of thumb is this: for
each ohm in series with the external transistor, there will be a
0.9°C error in the MIC281’s temperature measurement. It is
not difficult to keep the series resistance well below an ohm
(typically < 0.1
), so this will rarely be an issue.
Filter Capacitor Selection
It is usually desirable to employ a filter capacitor between the
T1 and GND pins of the MIC281. The use of this capacitor is
recommended in environments with a lot of high frequency
noise (such as digital switching noise), or if long traces or wires
are used to connect to the remote diode. The recommended
total capacitance from the T1 pin to GND is 2200pF. If the
remote diode is to be at a distance of more than 6”-12” from
the MIC281, using twisted pair wiring or shielded microphone
cable for the connections to the diode can significantly reduce
noise pickup. If using a long run of shielded cable, remember
to subtract the cable’s conductor-to-shield capacitance from
the 2200pF total capacitance.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MIC281-0YM6 | Low-Cost IttyBitty Thermal Sensor IttyBitty |
| MIC281-1BM6 | Low-Cost IttyBitty Thermal Sensor IttyBitty |
| MIC281-1YM6 | Low-Cost IttyBitty Thermal Sensor IttyBitty |
| MIC281-2BM6 | Low-Cost IttyBitty Thermal Sensor IttyBitty |
| MIC281-2YM6 | Low-Cost IttyBitty Thermal Sensor IttyBitty |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MIC281-0BM6 TR | 功能描述:IC SUPERVISOR THERMAL SOT23-6 RoHS:否 類別:集成電路 (IC) >> PMIC - 熱管理 系列:IttyBitty® 標(biāo)準(zhǔn)包裝:2,500 系列:SilentSense™ 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:-55°C ~ 125°C，外部傳感器 精確度:±2°C 本地（最大），±3°C 遠(yuǎn)程（最大） 拓?fù)?ADC（三角積分型），比較器，寄存器庫 輸出類型:I²C?/SMBus? 輸出警報:是 輸出風(fēng)扇:是 電源電壓:2.7 V ~ 5.5 V 工作溫度:-55°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:8-TSSOP，8-MSOP（0.118"，3.00mm 寬） 供應(yīng)商設(shè)備封裝:8-MSOP 包裝:帶卷 (TR) 其它名稱:MIC284-2BMMTRMIC284-2BMMTR-ND |
| MIC281-0BM6TR | 制造商:Rochester Electronics LLC 功能描述:- Tape and Reel |
| MIC2810-CGJYML | 制造商:Rochester Electronics LLC 功能描述: 制造商:RF Micro Devices Inc 功能描述: |
| MIC2810-CGJYML TR | 功能描述:線性穩(wěn)壓器 - 標(biāo)準(zhǔn) DC-DC + 2 Linear Regulators with LowQ mode and POR (Lead-Free) RoHS:否 制造商:STMicroelectronics 輸出類型: 極性: 輸出電壓:1.8 V 輸出電流:150 mA 負(fù)載調(diào)節(jié): 最大輸入電壓:5.5 V 線路調(diào)整率: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOT-323-5L |
| MIC2810-FGSYML TR | 功能描述:線性穩(wěn)壓器 - 標(biāo)準(zhǔn) DC-DC + 2 Linear Regulators with LowQ mode and POR (Lead-Free) RoHS:否 制造商:STMicroelectronics 輸出類型: 極性: 輸出電壓:1.8 V 輸出電流:150 mA 負(fù)載調(diào)節(jié): 最大輸入電壓:5.5 V 線路調(diào)整率: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOT-323-5L |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。