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參數(shù)資料
| 型號： | OP90 |
| 廠商： | Analog Devices, Inc. |
| 英文描述： | Precision Low-Voltage Micropower Operational Amplifier |
| 中文描述： | 精密低電壓微功率運算放大器 |
| 文件頁數(shù)： | 8/12頁 |
| 文件大小： | 653K |
| 代理商： | OP90 |
REV. A
OP90
–8–
Single-Supply Output Voltage Range
In single-supply operation, the OP90’s input and output ranges
include ground. This allows true “zero-in, zero-out” operation.
The output stage provides an active pull-down to around 0.8 V
above ground. Below this level, a load resistance of up to 1 M
to ground is required to pull the output down to zero.
In the region from ground to 0.8 V, the OP90 has voltage gain
equal to the data sheet specification. Output current source
capatibility is maintained over the entire voltage range includ-
ing ground.
APPLICATIONS
Battery-Powered Voltage Reference
The circuit of Figure 6 is a battery-powered voltage reference
that draws only 17
μ
A of supply current. At this level, two AA
cells can power this reference over 18 months. At an output voltage
of 1.23 V @ 25
°
C, drift of the reference is only at 5.5
μ
V/
°
C over
the industrial temperature range. Load regulation is 85
μ
V/mA
with line regulation at 120
μ
V/V.
Design of the reference is based on the bandgap technique.
Scaling of resistors R1 and R2 produces unequal currents in Q1
and Q2. The resulting V
BE
mismatch creates a temperature
proportional voltage across R3 which, in turn, produces a larger
temperature-proportional voltage across R4 and R5. This volt-
age appears at the output added to the V
BE
of Q1, which has an
opposite temperature coefficient. Adjusting the output to l.23 V
at 25
°
C produces minimum drift over temperature. Bandgap
references can have start-up problems. With no current in R1
and R2, the OP90 is beyond its positive input range limit and
has an undefined output state. Shorting Pin 5 (an offset adjust
pin) to ground, forces the output high under these conditions
and ensures reliable start-up without significantly degrading the
OP90’s offset drift.
4
2
3
5
6
7
OP90
R1
240k
R2
1.5M
C1
1000pF
V+
(2.5V TO 36V)
V
(1.23V @ 25 C)
6
5
7
3
2
1
R3
68k
R4
130k
R5
20k
OUTPUT
ADJUST
MAT-01AH
Figure 6. Battery-Powered Voltage Reference
HOURS
L
C
–
4
3
00
2000
7000
4000
2
1
1000
3000
6000
5000
Figure 3. Lithium Sulphur Dioxide Cell Discharge
Characteristic with OP90 and 100 k
Load
Input Voltage Protection
The OP90 uses a PNP input stage with protection resistors in
series with the inverting and noninverting inputs. The high
breakdown of the PNP transistors coupled with the protection
resistors provides a large amount of input protection, allowing
the inputs to be taken 20 V beyond either supply without dam-
aging the amplifier.
Offset Nulling
The offset null circuit of Figure 4 provides 6 mV of offset adjust-
ment range. A 100 k
resistor placed in a series with the wiper
of the offset null potentiometer, as shown in Figure 5, reduces
the offset adjustment range to 400
μ
V and is recommended for
applications requiring high null resolution. Offset nulling does not
affect TCV
OS
performance.
TEST CIRCUITS
V+
1
2
3
5
6
7
OP90
4
100k
V
–
Figure 4. Offset Nulling Circuit
V+
1
2
3
5
6
7
OP90
4
100k
V
–
100k
Figure 5. High Resolution Offset Nulling Circuit
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| OP-90 | 制造商:AD 制造商全稱:Analog Devices 功能描述:PRECISION, LOW VOLTAGE MICROPOWER OPERATIONAL AMPLIFIER |
| OP900SL | 功能描述:光電二極管 PN PHOTODIODE RoHS:否 制造商:Vishay Semiconductors 產(chǎn)品:Photodiodes 反向電壓:10 V 最大暗電流:30 nA 峰值波長:565 nm 上升時間:3.1 us 下降時間:3 us 半強度角度:50 deg 封裝 / 箱體:TO-5 |
| OP905 | 功能描述:光電二極管 Photodiode RoHS:否 制造商:Vishay Semiconductors 產(chǎn)品:Photodiodes 反向電壓:10 V 最大暗電流:30 nA 峰值波長:565 nm 上升時間:3.1 us 下降時間:3 us 半強度角度:50 deg 封裝 / 箱體:TO-5 |
| OP906 | 功能描述:光電二極管 Photodiode RoHS:否 制造商:Vishay Semiconductors 產(chǎn)品:Photodiodes 反向電壓:10 V 最大暗電流:30 nA 峰值波長:565 nm 上升時間:3.1 us 下降時間:3 us 半強度角度:50 deg 封裝 / 箱體:TO-5 |
| OP90ARC/883 | 制造商:AD 制造商全稱:Analog Devices 功能描述:PRECISION, LOW VOLTAGE MICROPOWER OPERATIONAL AMPLIFIER |
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