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參數(shù)資料
| 型號： | LT1991ACDD |
| 廠商： | Linear Integrated Systems |
| 英文描述： | nullPrecision, 100UA Gain Selectable Amplifier |
| 中文描述： | nullPrecision，100uA的可選增益放大器 |
| 文件頁數(shù)： | 9/24頁 |
| 文件大?。?/td> | 303K |
| 代理商： | LT1991ACDD |
LT1991
9
1991fb
The maximum voltage allowed on the P3, M3, P9, and M9
inputs includes the positive and negative supply plus a
diode drop. These pins should not be driven more than
0.2V outside of the supply rails. This is because they are
connected through diodes to internal manufacturing post-
package trim circuitry, and through a substrate diode to
V
EE
. If more than 10mA is allowed to flow through these
pins, there is a risk that the LT1991 will be detrimmed or
damaged. The P1 and M1 inputs do not have clamp diodes
or substrate diodes or trim circuitry and can be taken well
outside the supply rails. The maximum allowed voltage on
the P1 and M1 pins is
±
60V.
The input voltage range of the internal op amp extends to
within 1.2V of V
CC
and 1V of V
EE
. The voltage at which the
op amp inputs common mode is determined by the
voltage at the op amp’s +input, and this is determined by
the voltages on pins P1, P3, P9 and REF. (See “Calculating
Input Voltage Range” section.) This is true provided that
the op amp is functioning and feedback is maintaining the
inputs at the same voltage, which brings us to the third
requirement.
For valid circuit function, the op amp output must not be
clipped. The output will clip if the input signals are attempt-
ing to force it to within 40mV of its supply voltages. This
usually happens due to too large a signal level, but it can
also occur with zero input differential and must therefore
be included as an example of a common mode problem.
Consider Figure 1. This shows the LT1991 configured as
a gain of 13 difference amplifier on a single supply with the
output REF connected to ground. This is a great circuit, but
it does not support V
DM
= 0V at any common mode
because the output clips into ground while trying to
produce 0V
OUT
. It can be fixed simply by declaring the
valid input differential range not to extend below +4mV, or
by elevating the REF pin above 40mV, or by providing a
negative supply.
Calculating Input Voltage Range
Figure 2 shows the LT1991 in the generalized case of a
difference amplifier, with the inputs shorted for the com-
mon mode calculation. The values of R
F
and R
G
are
dictated by how the P inputs and REF pin are connected.
By superposition we can write:
V
INT
= V
EXT
(R
F
/(R
F
+ R
G
)) + V
REF
(R
G
/(R
F
+ R
G
))
Or, solving for V
EXT
:
V
EXT
= V
INT
(1 + R
G
/R
F
) – V
REF
R
G
/R
F
But valid V
INT
voltages are limited to V
CC
– 1.2V and V
EE
+
1V, so:
MAX V
EXT
= (V
CC
– 1.2) (1 + R
G
/R
F
) – V
REF
R
G
/R
F
and:
MIN V
EXT
= (V
EE
+ 1) (1 + R
G
/R
F
) – V
REF
R
G
/R
F
Figure 1. Difference Amplifier Cannot Produce
0V on a Single Supply. Provide a Negative
Supply, or Raise Pin 5, or Provide 4mV of V
DM
Figure 2. Calculating CM Input Voltage Range
APPLICATIU
W
U
U
–
+
1991 F01
50k
150k
450k
50k
150k
450k
450k
450k
REF
5V
V
2.5V
V
DM
0V
+
–
8
7
6
5
4
9
10
1
2
3
LT1991
V
OUT
= 13 V
DM
4pF
4pF
–
+
V
REF
R
F
R
F
R
G
R
G
1991 F02
V
EXT
V
INT
V
CC
V
EE
These two voltages represent the high and low extremes
of the common mode input range, if the other limits have
not already been exceeded (1 and 3, above). In most cases,
the inverting inputs M1 through M9 can be taken further
than these two extremes because doing this does not
move the op amp input common mode. To calculate the
limit on this additional range, see Figure 3. Note that, with
V
MORE
= 0, the op amp output is at V
REF
. From the max
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LT1991ACDD#PBF | 功能描述:IC AMP PREC GAIN SELECT 10-DFN RoHS:是 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 標準包裝:50 系列:- 放大器類型:通用 電路數(shù):2 輸出類型:滿擺幅 轉(zhuǎn)換速率:1.8 V/µs 增益帶寬積:6.5MHz -3db帶寬:4.5MHz 電流 - 輸入偏壓:5nA 電壓 - 輸入偏移:100µV 電流 - 電源:65µA 電流 - 輸出 / 通道:35mA 電壓 - 電源，單路/雙路(±):1.8 V ~ 5.25 V，±0.9 V ~ 2.625 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬） 供應(yīng)商設(shè)備封裝:10-MSOP 包裝:管件 |
| LT1991ACDD#TRPBF | 功能描述:IC AMP PREC GAIN SELECT 10-DFN RoHS:是 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 標準包裝:50 系列:LinCMOS™ 放大器類型:通用 電路數(shù):4 輸出類型:- 轉(zhuǎn)換速率:0.05 V/µs 增益帶寬積:110kHz -3db帶寬:- 電流 - 輸入偏壓:0.7pA 電壓 - 輸入偏移:210µV 電流 - 電源:57µA 電流 - 輸出 / 通道:30mA 電壓 - 電源，單路/雙路(±):3 V ~ 16 V，±1.5 V ~ 8 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:14-SOIC（0.154"，3.90mm 寬） 供應(yīng)商設(shè)備封裝:14-SOIC 包裝:管件 產(chǎn)品目錄頁面:865 (CN2011-ZH PDF) 其它名稱:296-1834296-1834-5 |
| LT1991ACDD-PBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Precision, 100μA Gain Selectable Amplifi er |
| LT1991ACDD-TRPBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Precision, 100μA Gain Selectable Amplifi er |
| LT1991ACMS | 功能描述:IC AMP PREC GAIN SELECT 10MSOP RoHS:否 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 標準包裝:50 系列:- 放大器類型:通用 電路數(shù):2 輸出類型:滿擺幅 轉(zhuǎn)換速率:1.8 V/µs 增益帶寬積:6.5MHz -3db帶寬:4.5MHz 電流 - 輸入偏壓:5nA 電壓 - 輸入偏移:100µV 電流 - 電源:65µA 電流 - 輸出 / 通道:35mA 電壓 - 電源，單路/雙路(±):1.8 V ~ 5.25 V，±0.9 V ~ 2.625 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬） 供應(yīng)商設(shè)備封裝:10-MSOP 包裝:管件 |
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