13 FN6145.4 August 16, 2011 expected supply currents and possible noise injection into the channel being used. The proper wa" />
參數(shù)資料
型號(hào): ISL28278FAZ-T7
廠商: Intersil
文件頁(yè)數(shù): 5/16頁(yè)
文件大?。?/td> 0K
描述: IC OPAMP DUAL RRIO PREC 16-QSOP
標(biāo)準(zhǔn)包裝: 1
放大器類(lèi)型: 通用
電路數(shù): 2
輸出類(lèi)型: 滿擺幅
轉(zhuǎn)換速率: 0.14 V/µs
增益帶寬積: 300kHz
電流 - 輸入偏壓: 10pA
電壓 - 輸入偏移: 0.2µV
電流 - 電源: 120µA
電流 - 輸出 / 通道: 31mA
電壓 - 電源,單路/雙路(±): 2.4 V ~ 5.5 V,±1.2 V ~ 2.75 V
工作溫度: -40°C ~ 125°C
安裝類(lèi)型: 表面貼裝
封裝/外殼: 16-SSOP(0.154",3.90mm 寬)
供應(yīng)商設(shè)備封裝: 16-QSOP
包裝: 標(biāo)準(zhǔn)包裝
產(chǎn)品目錄頁(yè)面: 1235 (CN2011-ZH PDF)
其它名稱(chēng): ISL28278FAZ-T7DKR
ISL28278, ISL28478
13
FN6145.4
August 16, 2011
expected supply currents and possible noise injection into the
channel being used. The proper way to prevent this oscillation is
to short the output to the negative input, and ground the positive
input (as shown in Figure 40).
Proper Layout Maximizes Performance
To achieve maximum performance from the high input
impedance and low offset voltage of the ISL28278 and
ISL28478, care should be taken in circuit board layout. The PC
board surface must remain clean and free of moisture to avoid
leakage currents between adjacent traces. Surface coating of the
circuit board reduces surface moisture and provides a humidity
barrier, reducing parasitic resistance on the board.
Current Limiting
The ISL28278 and ISL28478 have no internal current-limiting
circuitry. If the output is shorted, it is possible to exceed the
absolute maximum rating for output current or power
dissipation, potentially resulting in destruction of the device.
Power Dissipation
It is possible to exceed the +150°C maximum junction
temperatures under certain load and power-supply conditions. It
is therefore important to calculate the maximum junction
temperature (TJMAX) for all applications, to determine whether
power supply voltages, load conditions, or package type need to
be modified to remain in the safe operating area. These
parameters are related in Equation 1:
where:
TMAX = Maximum ambient temperature
θJA = Thermal resistance of the package
PDMAXTOTAL is the sum of the maximum power dissipation of
each amplifier in the package (PDMAX)
PDMAX for each amplifier is calculated in Equation 2:
where:
PDMAX = Maximum power dissipation of one amplifier
VS = Supply voltage (magnitude of V+ and V-)
ISMAX = Maximum supply current of one amplifier
VOUTMAX = Maximum output voltage swing of the application
RL = Load resistance
Application Circuits
THERMOCOUPLE AMPLIFIER
Thermocouples are the most popular temperature-sensing
device because of their low cost, interchangeability, and ability to
measure a wide range of temperatures. The ISL28x78 (see
Figure 41) is used to convert the differential thermocouple
voltage into a single-ended signal with 10x gain. The amplifier’s
rail-to-rail input characteristic allows the thermocouple to be
biased at ground and the amplifier to run from a single 5V
supply.
ECG AMPLIFIER
In medical applications, ECG amplifiers must extract millivolt low
frequency AC signals from the skin of the patient while rejecting
AC common mode interference and static DC potentials created
at the electrode-to-skin interface. In Figure 42, the ISL28278
(U1) forms one of the multiple high gain AC band-pass amplifiers
using active feedback. Amplifier U1B and RC RF1, CF1 form a
high gain LP filtered amplifier with the corner frequency given by
Equation 3:
Inserting the low pass amplifier, U1B, in the U1A feedback loop
results in an overall high-pass frequency response. Voltage
divider pairs R1-R2 and R3-R4 set the overall amplifier pass-band
gain. The DC input offset is canceled by U1B at the U1A inverting
input. Resistor divider pair R3-R4 defines the maximum input DC
level that is canceled, and is given by Equation 4:
In the passband range, U1B gain is +1, and the total signal gain
is defined by the divider ratios according to Equation 5:
At frequencies greater than the LPF corner, the R1-C1 and R3-C3
networks work to roll-off the U1A gain to unity. Setting both R-C
time constants to the same value simplifies to Equation 6:
Right leg drive and reference amplifiers U2A and U2B form a DC
feedback loop that applies a correction voltage at the right leg
FIGURE 40. PREVENTING OSCILLATIONS IN UNUSED CHANNELS
-
+
1/2 ISL28278
1/4 ISL28478
TJMAX
TMAX θJAxPDMAXTOTAL
()
+
=
(EQ. 1)
PDMAX
2*VS ISMAX VS
(
- VOUTMAX)
VOUTMAX
RL
------------------------
×
+
×
=
(EQ. 2)
-
+
5V
+
V+
V-
ISL28x78
10k
R3
10k
R2
R4
100k
R1
100k
410V/°C
FIGURE 41. THERMOCOUPLE AMPLIFIER
COLD JUNCTION
COMPENSATION
K TYPE
THERMOCOUPLE
f-HPF-3dB
1
2Pi
×
RF1
×
CF1
×
--------------------------------------------------
=
(EQ. 3)
VINDC
V+
R4
R3 R4
+
--------------------
×
=
(EQ. 4)
VOUTU1 GAIN
VOUT
VIN
-------------
R1 R2
+
R2
--------------------
R3 R4
+
R4
--------------------
×
=
(EQ. 5)
f-LPF-3dB
1
2Pi
×
R1
×
C1
×
-----------------------------------------
=
(EQ. 6)
相關(guān)PDF資料
PDF描述
AD8008ARMZ-REEL IC OPAMP CF DUAL ULDIST LN 8MSOP
0713085724 CONN SMD BKWY HDR TIN 24POS
AS168X-CB2H300 CIRCUIT BRKR THERMAL 30.0A 2POLE
0713085498 CONN HEADER BKWY SMD TIN 98POS
AS168X-CB2H250 CIRCUIT BRKR THERMAL 25.0A 2POLE
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ISL28278FAZ-TZ 制造商:Rochester Electronics LLC 功能描述: 制造商:Intersil Corporation 功能描述:
ISL28286 制造商:INTERSIL 制造商全稱(chēng):Intersil Corporation 功能描述:Dual and Quad Micropower Single Supply Dual and Quad Micropower Single Supply Precision Op Amp
ISL28286_07 制造商:INTERSIL 制造商全稱(chēng):Intersil Corporation 功能描述:Dual and Quad Micropower Single Supply Dual and Quad Micropower Single Supply Precision Op Amp
ISL28286EVAL1Z 功能描述:EVALUATION BOARD FOR ISL28286 RoHS:是 類(lèi)別:編程器,開(kāi)發(fā)系統(tǒng) >> 評(píng)估板 - 運(yùn)算放大器 系列:- 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:-
ISL28286FUZ 功能描述:IC OPAMP DUAL RRIO PREC 10-MSOP RoHS:是 類(lèi)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(lèi)型:通用 電路數(shù):1 輸出類(lèi)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(lèi)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(chēng):MAX4475AUT#TG16DKR