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參數(shù)資料
| 型號： | MAX981 |
| 廠商： | Maxim Integrated Products, Inc. |
| 英文描述： | Ultra-Low-Power, Open-Drain, Single/Dual-Supply Comparators |
| 中文描述： | 超低功耗、漏極開路輸出、單/雙電源比較器 |
| 文件頁數(shù)： | 11/16頁 |
| 文件大?。?/td> | 109K |
| 代理商： | MAX981 |
2) Select R1. The leakage current into INB- is normally
under 1nA, so the current through R1 should exceed
100nA for the thresholds to be accurate. R1 values
up to about 10M
can be used, but values in the
100k
to 1M
range are usually easier to deal with.
In this example, choose R1 = 294k
.
3) Calculate R2 + R3. The overvoltage threshold
should be 5.5V when V
IN
is rising. The design
equation is as follows:
V
V
REF
=
4) Calculate R2. The undervoltage threshold should be
4.5V when V
IN
is falling. The design equation is as
follows:
5) Calculate R3:
R3
=
=
=
Choose R3 = 1M
(1% standard value)
6) Verify the resistor values. The equations are as
follows, evaluated for the above example:
Overvoltage Threshold:
Battery S witc hover Circ uit
The switchover from line-powered DC to a backup
battery is often accomplished with diodes. But this
simple method is sometimes unacceptable, due to the
voltage drop and associated power loss across the
diode in series with the battery. Figure 6’s circuit
replaces the diode with a P-channel MOSFET
controlled by one of the MAX9_3 comparator outputs.
When the DC wall adapter drops below 4V (determined
by R1 and R2), OUTA goes low, turning on Q1.
Comparator B is used to measure the battery voltage,
and gives a “l(fā)ow-battery” indication when the battery
drops below 3.6V.
Level S hifter
Figure 7 shows a circuit to shift from bipolar ±5V inputs
to single-ended +5V outputs. The 10k
resistors
protect the comparator inputs, and do not materially
affect the circuit’s operation.
V
(V
V )
(R1
R2
R1
R3)
Undervoltage Threshold:
5.474V
V
(V
V )
(R1
R2
R3)
(R1 + R2)
4.484V
where the hysteresis voltage V
V
R5
R4
OTH
REF
UTH
REF
REF
=
+
×
+
+
=
=
×
+
+
=
=
×
.
(R2 + R3)
.068M
1.006M
R2
1 9
.
6
k
1
R2
(R1 + R2 + R3)
(V
V )
V
R1
(294k + 1.068M)
(1.182
0.005)
4.5
294k
62.2k
Choose R2
61.9k (1% standard value).
REF
UTH
=
×
=
×
=
=
R2
R3
R1
V
1
294k
5.5
+
(1.182
0.005)
1
1.068M
OTH
H
+
=
×
+
=
×
M
Ultra-Low-Power, Open-Drain,
S ingle/Dual-S upply Comparators
______________________________________________________________________________________
11
MAX9_3
INB-
REF
HYST
INA+
3
5
6
4
1
8
V-
2
V+
7
1M
OUTA
OUTB
R5
10k
R1
294k
R2
62.2k
R3
1M
POWER GOOD
V
IN
V
OTH
= 5.5V
V
UTH
= 4.5V
R4
2.4M
+5V
Figure 5. Window Detector
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX9810AEBS | 制造商:Maxim Integrated Products 功能描述:LECTRET CONDENSER MICROPHONE CARTR - Rail/Tube |
| MAX9810AEBS+T | 功能描述:傳聲器前置放大器 RoHS:否 制造商:Texas Instruments 可用增益調(diào)整:Digital control, 65 dB to 0 dB 共模抑制比（最小值）: 輸入補償電壓: 最大輸入電阻:9200 Ohms 最大工作溫度:+ 85 C 封裝 / 箱體:SSOP-28 封裝:Tube |
| MAX9810AEBS-T | 功能描述:傳聲器前置放大器 RoHS:否 制造商:Texas Instruments 可用增益調(diào)整:Digital control, 65 dB to 0 dB 共模抑制比（最小值）: 輸入補償電壓: 最大輸入電阻:9200 Ohms 最大工作溫度:+ 85 C 封裝 / 箱體:SSOP-28 封裝:Tube |
| MAX9810BEBS | 制造商:Maxim Integrated Products 功能描述:LECTRET CONDENSER MICROPHONE CARTR - Rail/Tube |
| MAX9810BEBS+T | 功能描述:傳聲器前置放大器 RoHS:否 制造商:Texas Instruments 可用增益調(diào)整:Digital control, 65 dB to 0 dB 共模抑制比（最小值）: 輸入補償電壓: 最大輸入電阻:9200 Ohms 最大工作溫度:+ 85 C 封裝 / 箱體:SSOP-28 封裝:Tube |
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