參數(shù)資料
型號(hào)： LT1991AIDD
廠商： Linear Integrated Systems
英文描述： Precision, 100UA Gain Selectable Amplifier
中文描述： 精密，100uA的可選增益放大器
文件頁(yè)數(shù)： 8/24頁(yè)
文件大?。?/td> 311K
代理商： LT1991AIDD
LT1991
8
1991fb
Introduction
The LT1991 may be the last op amp you ever have to stock.
Because it provides you with several precision matched
resistors, you can easily configure it into several different
classical gain circuits without adding external compo-
nents. The several pages of simple circuits in this data
sheet demonstrate just how easy the LT1991 is to use. It
can be configured into difference amplifiers, as well as into
inverting and noninverting single ended amplifiers. The
fact that the resistors and op amp are provided together in
such a small package will often save you board space and
reduce complexity for easy probing.
The Op Amp
The op amp internal to the LT1991 is a precision device
with 15
μ
V typical offset voltage and 3nA input bias cur-
rent. The input offset current is extremely low, so match-
ing the source resistance seen by the op amp inputs will
provide for the best output accuracy. The op amp inputs
are not rail-to-rail, but extend to within 1.2V of V
CC
and 1V
of V
EE
. For many configurations though, the chip inputs
will function rail-to-rail because of effective attenuation to
the +input. The output is truly rail-to-rail, getting to within
40mV of the supply rails. The gain bandwidth product of
the op amp is about 560kHz. In noise gains of 2 or more,
it is stable into capacitive loads up to 500pF. In noise gains
below 2, it is stable into capacitive loads up to 100pF.
The Resistors
The resistors internal to the LT1991 are very well matched
SiChrome based elements protected with barrier metal.
Although their absolute tolerance is fairly poor (
±
30%),
their matching is to within 0.04%. This allows the chip to
achieve a CMRR of 75dB, and gain errors within 0.04%.
The resistor values are 50k, 150k, and 2 of 450k, con-
nected to each of the inputs. The resistors have power
limitations of 1watt for the 450k resistors, 0.3watt for the
150k resistors and 0.5watt for the 50k resistors; however,
in practice, power dissipation will be limited well below
these values by the maximum voltage allowed on the input
and REF pins. The 450k resistors connected to the M1 and
P1 inputs are isolated from the substrate, and can there-
fore be taken beyond the supply voltages. The naming of
the pins “P1,” “P3,” “P9,” etc., is based on their relative
admittances. Because it has 9 times the admittance, the
voltage applied to the P9 input has 9 times the effect of the
voltage applied to the P1 input.
Bandwidth
The bandwidth of the LT1991 will depend on the gain you
select (or more accurately the noise gain resulting from
the gain you select). In the lowest configurable gain of 1,
the –3dB bandwidth is limited to 450kHz, with peaking of
about 2dB at 280kHz. In the highest configurable gains,
bandwidth is limited to 32kHz.
Input Noise
The LT1991 input noise is dominated by the Johnson
noise of the internal resistors (
√
4kTR). Paralleling all four
resistors to the +input gives a 32.1k
resistance, for
23nV/
√
Hz of voltage noise. The equivalent network on the
–input gives another 23nV/
√
Hz, and taking their RMS sum
gives a total 33nV/
√
Hz input referred noise floor. Output
noise depends on configuration and noise gain.
Input Resistance
The LT1991 input resistances vary with configuration, but
once configured are apparent on inspection. Note that
resistors connected to the op amp’s –input are looking
into a virtual ground, so they simply parallel. Any feedback
resistance around the op amp does not contribute to input
resistance. Resistors connected to the op amp’s +input
are looking into a high impedance, so they add as parallel
or series depending on how they are connected, and
whether or not some of them are grounded. The op amp
+input itself presents a very high G
impedance. In the
classical noninverting op amp configuration, the LT1991
presents the high input impedance of the op amp, as is
usual for the noninverting case.
Common Mode Input Voltage Range
The LT1991 valid common mode input range is limited by
three factors:
1. Maximum allowed voltage on the pins
2. The input voltage range of the internal op amp
3. Valid output voltage
APPLICATIOU
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LT1991AIDD#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:- 其它有關(guān)文件:Automotive Product Guide 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:- 放大器類型:通用 電路數(shù):1 輸出類型:滿擺幅 轉(zhuǎn)換速率:3 V/µs 增益帶寬積:10MHz -3db帶寬:- 電流 - 輸入偏壓:1pA 電壓 - 輸入偏移:70µV 電流 - 電源:2.5mA 電流 - 輸出 / 通道:48mA 電壓 - 電源，單路/雙路(±):2.7 V ~ 5.5 V，±1.35 V ~ 2.75 V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-6 供應(yīng)商設(shè)備封裝:SOT-6 包裝:Digi-Reel® 其它名稱:MAX4475AUT#TG16DKR
LT1991AIDD#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:- 其它有關(guān)文件:Automotive Product Guide 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:- 放大器類型:通用 電路數(shù):1 輸出類型:滿擺幅 轉(zhuǎn)換速率:3 V/µs 增益帶寬積:10MHz -3db帶寬:- 電流 - 輸入偏壓:1pA 電壓 - 輸入偏移:70µV 電流 - 電源:2.5mA 電流 - 輸出 / 通道:48mA 電壓 - 電源，單路/雙路(±):2.7 V ~ 5.5 V，±1.35 V ~ 2.75 V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-6 供應(yīng)商設(shè)備封裝:SOT-6 包裝:Digi-Reel® 其它名稱:MAX4475AUT#TG16DKR
LT1991AIDD-PBF 制造商:LINER 制造商全稱:Linear Technology 功能描述:Precision, 100μA Gain Selectable Amplifi er
LT1991AIDD-TRPBF 制造商:LINER 制造商全稱:Linear Technology 功能描述:Precision, 100μA Gain Selectable Amplifi er
LT1991AIMS 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(biāo)準(zhǔn)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(yè)面:865 (CN2011-ZH PDF) 其它名稱:296-1834296-1834-5
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