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參數(shù)資料
| 型號： | OPA129PB |
| 英文描述： | Ultra-Low Bias Current Difet OPERATIONAL AMPLIFIER |
| 中文描述： | 超低偏置電流Difet運算放大器 |
| 文件頁數(shù)： | 6/7頁 |
| 文件大?。?/td> | 640K |
| 代理商： | OPA129PB |
OPA129
6
0
Supply Voltage (±V
CC
)
COMMON-MODE INPUT RANGE vs SUPPLY VOLTAGE
C
5
10
0
20
15
10
5
15
BIAS CURRENT vs ADDITIONAL POWER DISSIPATION
Additional Power Dissipation (mW)
B
100pA
10pA
1pA
100
10
1
0
200
350
50
100
150
250
300
TYPICAL PERFORMANCE CURVES
(CONT)
T
A
= +25
°
C, +15VDC, unless otherwise noted.
APPLICATIONS INFORMATION
NON-STANDARD PINOUT
The OPA129 uses a non-standard pinout to achieve lowest
possible input bias current. The negative power supply is
connected to pin 5—see Figure 1. This is done to reduce the
leakage current from the V- supply (pin 4 on conventional
op amps) to the op amp input terminals. With this new
pinout, sensitive inputs are separated from both power
supply pins.
FIGURE 1. Offset Adjust Circuit.
OFFSET VOLTAGE TRIM
The OPA129 has no conventional offset trim connections.
Pin 1, next to the critical inverting input, has no internal
connection. This eliminates a source of leakage current and
allows guarding of the input terminals. Pin 1 and pin 4, next
to the two input pins, have no internal connection. This
allows an optimized circuit board layout with guarding—see
“circuit board layout.”
Due to its laser-trimmed input stage, most applications do
not require external offset voltage trimming. If trimming is
required, the circuit shown in Figure 1 can be used. Power
supply voltages are divided down, filtered and applied to the
non-inverting input. The circuit shown is sensitive to varia-
tion in the supply voltages. Regulation can be added, if
needed.
GUARDING AND SHIELDING
Ultra-low input bias current op amps require precautions to
achieve best performance. Leakage current on the surface of
circuit board can exceed the input bias current of the ampli-
fier. For example, a circuit board resistance of 10
12
from
a power supply pin to an input pin produces a current of
15pA—more than one-hundred times the input bias current
of the op amp.
To minimize surface leakage, a guard trace should com-
pletely surround the input terminals and other circuitry
connecting to the inputs of the op amp. The DIP package
should have a guard trace on both sides of the circuit board.
The guard ring should be driven by a circuit node equal in
potential to the op amp inputs—see Figure 2. The substrate,
pin 8, should also be connected to the circuit board guard to
assure that the amplifier is fully surrounded by the guard
potential. This minimizes leakage current and noise pick-up.
Careful shielding is required to reduce noise pickup. Shield-
ing near feedback components may also help reduce noise
pick-up.
Triboelectric effects (friction-generated charge) can be a
troublesome source of errors. Vibration of the circuit board,
input connectors and input cables can cause noise and drift.
Make the assembly as rigid as possible. Attach cables to
avoid motion and vibration. Special low noise or low leak-
age cables may help reduce noise and leakage current. Keep
all input connections as short possible. Surface-mount com-
ponents may reduce circuit board size and allow a more rigid
assembly.
OPA129
V
OUT
V
IN
R
F
R
IN
2
3
6
7
5
V+
V–
0.1μF
220
470k
470k
V–
V+
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| OPA129U | 功能描述:運算放大器 - 運放 Ultra-Low Bias Current Difet RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比（最小值）:63 dB 輸入補償電壓:1 mV 輸入偏流（最大值）:10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-16 轉(zhuǎn)換速度:0.89 V/us 關(guān)閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel |
| OPA129UB | 功能描述:運算放大器 - 運放 Ultra-Low Bias Current Difet RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比（最小值）:63 dB 輸入補償電壓:1 mV 輸入偏流（最大值）:10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-16 轉(zhuǎn)換速度:0.89 V/us 關(guān)閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel |
| OPA129UB | 制造商:Texas Instruments 功能描述:OPERATIONAL AMPLIFIER (OP-AMP) IC ((NW)) |
| OPA129UB/2K5 | 功能描述:運算放大器 - 運放 Ultra-Low Bias Current Difet RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比（最小值）:63 dB 輸入補償電壓:1 mV 輸入偏流（最大值）:10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-16 轉(zhuǎn)換速度:0.89 V/us 關(guān)閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel |
| OPA129UB/2K5E4 | 功能描述:運算放大器 - 運放 Ultra-Low Bias Current Difet RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比（最小值）:63 dB 輸入補償電壓:1 mV 輸入偏流（最大值）:10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-16 轉(zhuǎn)換速度:0.89 V/us 關(guān)閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel |
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