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參數(shù)資料
| 型號(hào)： | OP295GS |
| 廠商： | ANALOG DEVICES INC |
| 元件分類： | 運(yùn)動(dòng)控制電子 |
| 英文描述： | DUAL/QUAD RAIL-TO-RAIL OPERATIONAL AMPLIFIERS |
| 中文描述： | DUAL OP-AMP, 800 uV OFFSET-MAX, 0.085 MHz BAND WIDTH, PDSO8 |
| 封裝： | MS-012AA, SOIC-8 |
| 文件頁(yè)數(shù)： | 10/12頁(yè) |
| 文件大小： | 328K |
| 代理商： | OP295GS |
REV. B
–10–
OP295/OP495
current budget with which the circuit must operate. T his circuit
consumes only 1.4 mA maximum quiescent current, making 2.6
mA of current available to power additional signal conditioning
circuitry or to power a bridge circuit.
A 3 Volt Low-Dropout Linear Voltage Regulator
Figure 10 shows a simple 3 V voltage regulator design. T he
regulator can deliver 50 mA load current while allowing a 0.2 V
dropout voltage. T he OP295/OP495’s rail-to-rail output swing
handily drives the MJE350 pass transistor without requiring spe-
cial drive circuitry. At no load, its output can swing less than the
pass transistor’s base-emitter voltage, turning the device nearly
off. At full load, and at low emitter-collector voltages, the tran-
sistor beta tends to decrease. T he additional base current is eas-
ily handled by the OP295/OP495 output.
T he amplifier servos the output to a constant voltage, which
feeds a portion of the signal to the error amplifier.
Higher output current, to 100 mA, is achievable at a higher
dropout voltage of 3.8 V.
1000pF
43k
44.2k
1%
30.9k
1%
AD589
1.235V
V
O
100
μ
F
I
L
< 50mA
MJE 350
V
IN
5V TO 3.2V
1/2
OP295/
OP495
4
8
1
2
3
Figure 10. 3 V Low Dropout Voltage Regulator
Figure 11 shows the regulator’s recovery characteristic when its
output underwent a 20 mA to 50 mA step current change.
10
100
0%
90
1ms
20mV
2V
50mA
20mA
OUTPUT
STEP
CURRENT
CONTROL
WAVEFORM
Figure 11. Output Step Load Current Recovery
Low-Dropout, 500 mA Voltage Regulator with Fold-Back
Current Limiting
Adding a second amplifier in the regulation loop as shown in
Figure 12 provides an output current monitor as well as fold-
back current limiting protection.
Amplifier A1 provides error amplification for the normal voltage
regulation loop. As long as the output current is less than 1 am-
pere, amplifier A2’s output swings to ground, reverse biasing the
diode and effectively taking itself out of the circuit. However, as
the output current exceeds 1 amp, the voltage that develops
across the 0.1
sense resistor forces the amplifier A2’s output
to go high, forward-biasing the diode, which in turn closes the
current limit loop. At this point A2’s lower output resistance
dominates the drive to the power MOSFET transistor, thereby
effectively removing the A1 voltage regulation loop from the
circuit.
If the output current greater than 1 amp persists, the current
limit loop forces a reduction of current to the load, which causes
a corresponding drop in output voltage. As the output voltage
drops, the current limit threshold also drops fractionally, result-
ing in a decreasing output current as the output voltage de-
creases, to the limit of less than 0.2 A at 1 V output. T his
“fold-back” effect reduces the power dissipation considerably
during a short circuit condition, thus making the power supply
far more forgiving in terms of the thermal design requirements.
Small heat sinking on the power MOSFET can be tolerated.
T he OP295’s rail-to-rail swing exacts higher gate drive to
the power MOSFET , providing a fuller enhancement to the
transistor. T he regulator exhibits 0.2 V dropout at 500 mA of
load current. At 1 amp output, the dropout voltage is typically
5.6 volts.
124k
1%
124k
1%
REF43
4
6
2
0.01
μ
F
100k
5%
210k
1%
205k
1%
45.3k
1%
45.3k
1%
R
0.1
1/4W
+5V V
O
I
O
(NORM) = 0.5A
I
O
(MAX) = 1A
S
D
G
IRF9531
1N4148
2.500V
A1
4
A2
1
3
2
8
7
5
6
6V
1/2
OP295/
OP495
1/2
OP295/
OP495
Figure 12. Low Dropout, 500 mA Voltage Regulator with
Fold-Back Current Limiting
Square Wave Oscillator
T he circuit in Figure 13 is a square wave oscillator (note the
positive feedback). T he rail-to-rail swing of the OP295/OP495
helps maintain a constant oscillation frequency even if the sup-
ply voltage varies considerably. Consider a battery powered sys-
tem where the voltages are not regulated and drop over time.
T he rail-to-rail swing ensures that the noninverting input sees
the full V+/2, rather than only a fraction of it.
T he constant frequency comes from the fact that the 58.7 k
feedback sets up Schmitt T rigger threshold levels that are di-
rectly proportional to the supply voltage, as are the RC charge
voltage levels. As a result, the RC charge time, and therefore the
frequency, remains constant independent of supply voltage. T he
slew rate of the amplifier limits the oscillation frequency to a
maximum of about 800 Hz at a +5 V supply.
Single Supply Differential Speaker Driver
Connected as a differential speaker driver, the OP295/OP495
can deliver a minimum of 10 mA to the load. With a 600
load, the OP295/OP495 can swing close to 5 volts peak-to-peak
across the load.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| OP495GS | DUAL/QUAD RAIL-TO-RAIL OPERATIONAL AMPLIFIERS |
| op295 | Rail to Rail Dual OP AMP(滿幅度雙運(yùn)算放大器) |
| op495 | Rail to Rail Quad OP AMP(滿幅度四運(yùn)算放大器) |
| OP296 | Micropower, Rail-to-Rail Input and Output Operational Amplifiers(微功耗,滿幅度輸入輸出雙運(yùn)放) |
| OP496 | Micropower, Rail-to-Rail Input and Output Operational Amplifiers(微功耗,滿幅度輸入輸出四運(yùn)放) |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| OP295GS | 制造商:Analog Devices 功能描述:SEMICONDUCTORSLINEAR |
| OP295GSREEL | 制造商:ANALOG 功能描述:NEW |
| OP295GS-REEL | 功能描述:IC OPAMP GP R-R 85KHZ DUAL 8SOIC RoHS:否 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 |
| OP295GS-REEL7 | 功能描述:IC OPAMP GP R-R 85KHZ DUAL 8SOIC RoHS:否 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 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:- 放大器類型:電流檢測(cè) 電路數(shù):1 輸出類型:- 轉(zhuǎn)換速率:- 增益帶寬積:125kHz -3db帶寬:- 電流 - 輸入偏壓:- 電壓 - 輸入偏移:100µV 電流 - 電源:1.1µA 電流 - 輸出 / 通道:- 電壓 - 電源，單路/雙路(±):- 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:4-WFBGA，CSPBGA 供應(yīng)商設(shè)備封裝:4-UCSP（2x2） 包裝:剪切帶 (CT) 其它名稱:MAX9634WERS+TCT |
| OP295GS-REEL7-RAYTON | 制造商:Analog Devices 功能描述: |
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