參數(shù)資料
型號: LT1673CN8
元件分類: 運算放大器
英文描述: Voltage-Feedback Operational Amplifier
中文描述: 電壓反饋運算放大器
文件頁數(shù): 9/12頁
文件大?。?/td> 208K
代理商: LT1673CN8
9
LT1672/LT1673/LT1674
and (V
CC
– 0.8V), Q1 and Q2 are active. When the input
common mode exceeds (V
CC
– 0.8V), Q7 turns on,
diverting the current from diff amp Q1-Q2 to current
mirror Q8-Q9. The current from Q8 biases on the other
diff amp consisting of PNP’s Q5-Q6 and NPN’s Q3-Q4.
Though Q5-Q6 are driven from the emitters rather than
the base, the basic diff amp action is the same. When the
common mode voltage is between (V
CC
– 0.8V) and V
CC
,
devices Q3 and Q4 act as followers, forming a buffer
between the amplifier inputs and the emitters of the Q5-
Q6. If the common mode voltage is taken above V
CC
,
Schottky diodes D1 and D2 reverse bias and devices Q3
and Q4 then act as diodes. The diff amp formed by Q5-Q6
operates normally, however, the input bias current in-
creases to the emitter current of Q5-Q6, which is typically
180nA. The graph, Input Bias Current vs Common Mode
Voltage found in the Typical Performance Characteristics
section, shows these transitions at three temperatures.
The collector currents of the two-input pairs are combined
in the second stage consisting of Q11 to Q16, which
furnishes most of the voltage gain. Capacitor C1 sets the
amplifier bandwidth. The output stage is configured for
maximum swing by the use of common emitter output
devices Q21 and Q22. Diodes D4 to D6 and current source
Q15 set the output quiescent current.
Figure 3. Simplified Schematic
1672/3/4 F03
Q6
Q4
Q16
Q17
(V
+
) – 0.8V
Q19
Q18
Q22
C1
D1
D2
D3
Q3
Q11
Q2
Q7
IN
IN
+
Q10
Q13
Q20
Q21
OUT
Q12
Q14
Q15
Q5
Q8
R1
R2
I
2
+
I
1
D6
D5
D4
D7
Q9
Q1
APPLICATIOU
The device will not be damaged if the inputs are taken lower
than 300mV below the negative supply as long as the cur-
rent out of the pin is limited to less than 10mA. However,
the output phase is not guaranteed and the supply current
will increase.
W
U
U
Output
The graph, Capacitive Load Handling, shows amplifier sta-
bility with the output biased at half supply. If the output is
to be operated within about 100mV of the positive rail, the
allowable load capacitance is less. With this output volt-
age, the worst case occurs at A
V
= 5 and light loads, where
the load capacitance should be less than 500pF with a 5V
supply and less than 100pF with a 30V supply.
Rail-to-Rail Operation
The simplified schematic, Figure 3, details the circuit
design approach of the
LT1672/LT1673/LT1674
. The
amplifier topology is a three-stage design consisting of a
rail-to-rail input stage, that continues to operate with the
inputs above the positive rail, a folded cascode second
stage that develops most of the voltage gain, and a rail-to-
rail common emitter stage that provides the current gain.
The input stage is formed by two diff amps Q1-Q2 and Q3-
Q6. For signals with a common mode voltage between V
EE
相關PDF資料
PDF描述
LT1673IN8 Voltage-Feedback Operational Amplifier
LT1673IS8 Voltage-Feedback Operational Amplifier
LT1674CN Voltage-Feedback Operational Amplifier
LT1674CS Voltage-Feedback Operational Amplifier
LT1674IN Voltage-Feedback Operational Amplifier
相關代理商/技術參數(shù)
參數(shù)描述
LT1673CN8#PBF 功能描述:IC OPAMP R-R IN/OUT DUAL 8-DIP RoHS:是 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:Over-The-Top® 標準包裝:2,500 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:0.11 V/µs 增益帶寬積:350kHz -3db帶寬:- 電流 - 輸入偏壓:4nA 電壓 - 輸入偏移:20µV 電流 - 電源:260µA 電流 - 輸出 / 通道:20mA 電壓 - 電源,單路/雙路(±):2.7 V ~ 36 V,±1.35 V ~ 18 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC(0.154",3.90mm 寬) 供應商設備封裝:8-SO 包裝:帶卷 (TR)
LT1673CS8 功能描述:IC OPAMP R-R IN/OUT DUAL 8-SOIC RoHS:否 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:Over-The-Top® 標準包裝:100 系列:- 放大器類型:通用 電路數(shù):1 輸出類型:- 轉(zhuǎn)換速率:0.2 V/µs 增益帶寬積:- -3db帶寬:- 電流 - 輸入偏壓:100pA 電壓 - 輸入偏移:30µV 電流 - 電源:380µA 電流 - 輸出 / 通道:- 電壓 - 電源,單路/雙路(±):±2 V ~ 18 V 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC(0.154",3.90mm 寬) 供應商設備封裝:8-SO 包裝:管件
LT1673CS8#PBF 功能描述:IC OPAMP R-R IN/OUT DUAL 8-SOIC RoHS:是 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:Over-The-Top® 標準包裝:100 系列:- 放大器類型:通用 電路數(shù):1 輸出類型:- 轉(zhuǎn)換速率:0.2 V/µs 增益帶寬積:- -3db帶寬:- 電流 - 輸入偏壓:100pA 電壓 - 輸入偏移:30µV 電流 - 電源:380µA 電流 - 輸出 / 通道:- 電壓 - 電源,單路/雙路(±):±2 V ~ 18 V 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC(0.154",3.90mm 寬) 供應商設備封裝:8-SO 包裝:管件
LT1673CS8#TR 功能描述:IC OPAMP R-R IN/OUT DUAL 8-SOIC RoHS:否 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:Over-The-Top® 標準包裝:100 系列:- 放大器類型:通用 電路數(shù):1 輸出類型:- 轉(zhuǎn)換速率:0.2 V/µs 增益帶寬積:- -3db帶寬:- 電流 - 輸入偏壓:100pA 電壓 - 輸入偏移:30µV 電流 - 電源:380µA 電流 - 輸出 / 通道:- 電壓 - 電源,單路/雙路(±):±2 V ~ 18 V 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC(0.154",3.90mm 寬) 供應商設備封裝:8-SO 包裝:管件
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