參數(shù)資料
型號(hào): OP777
廠商: Analog Devices, Inc.
英文描述: Precision Micropower Single Supply Operational Amplifier
中文描述: 精密微功耗單電源運(yùn)算放大器
文件頁(yè)數(shù): 11/12頁(yè)
文件大?。?/td> 162K
代理商: OP777
OP777
–11–
REV. 0
Phase Reversal
Many amplifiers misbehave when one or both of the inputs are
forced beyond the input common-mode voltage range. Phase
reversal is typified by the transfer function of the amplifier, effectively
reversing its transfer polarity. In some cases this can cause lockup in
servo systems and may cause permanent damage or nonrecoverable
parameter shifts to the amplifier. Many amplifiers feature compensa-
tion circuitry to combat these effects, but some are only effective for
the inverting input. Additionally, many of these schemes only work
for a few hundred millivolts or so beyond the supply rails. OP777
has a protection circuit against phase reversal when one or both
inputs are forced beyond their input common voltage range. It
is not recommended that the parts be continuously driven more
than 3 V beyond the rails.
TIME
400 s/DIV
V
V
SY
= 15V
V
IN
V
OUT
Figure 45. No Phase Reversal
Output Stage
The CMOS output stage has excellent (and fairly symmetric) output
drive and with light loads can actually swing to within 1 mV of both
supply rails. This is considerably better than similar amplifiers
featuring (so-called) rail-to-rail bipolar output stages. OP777 is
stable in the voltage follower configuration and responds to signals
as low as 1 mv above ground in single supply operation.
2.7V TO 30V
V
IN
= 1mV
OP777
V
OUT
= 1mV
Figure 46. Follower Circuit
TIME
10 s/DIV
V
1.0mV
Figure 47. Rail-to-Rail Operation
Output Short Circuit
The output of the OP777 series amplifier is protected from damage
against accidental shorts to either supply voltage, provided that the
maximum die temperature is not exceeded on a long-term basis (see
Absolute Maximum Rating section). Current of up to 30 mA does
not cause any damage.
A Low-Side Current Monitor
In the design of power supply control circuits, a great deal of design
effort is focused on ensuring a pass transistor’s long-term reliability
over a wide range of load current conditions. As a result, monitoring
and limiting device power dissipation is of prime importance in
these designs. Figure 48 shows an example of 5 V, single supply
current monitor that can be incorporated into the design of a voltage
regulator with foldback current limiting or a high current power
supply with crowbar protection. The design capitalizes on the
OP777’s common-mode range that extends to ground. Current
is monitored in the power supply return where a 0.1
shunt
resistor, R
SENSE
, creates a very small voltage drop. The voltage at the
inverting terminal becomes equal to the voltage at the noninverting
terminal through the feedback of Q1, which is a 2N2222 or equiva-
lent NPN transistor. This makes the voltage drop across R1 equal to
the voltage drop across R
SENSE
. Therefore, the current through Q1
becomes directly proportional to the current through R
SENSE
, and
the output voltage is given by:
V
V
R
R
R
I
OUT
SENSE
L
=
×
×
5
2
1
The voltage drop across
R
2 increases with
I
L
increasing, so
V
OUT
,
decreases with higher supply current being sensed. For the element
values shown, the V
OUT
transfer characteristic is –2.5 V/A, decreas-
ing from V
EE
.
5V
2.49k
OP777
5V
100
V
OUT
Q1
RETURN TO
GROUND
0.1
R
SENSE
Figure 48. A Low-Side Load Current Monitor
相關(guān)PDF資料
PDF描述
OP77GS NEXT GENERATION OP07, ULTRALOW OFFSET VOLTAGE OPERATIONAL AMPLIFIER
OP77FJ NEXT GENERATION OP07, ULTRALOW OFFSET VOLTAGE OPERATIONAL AMPLIFIER
OP77FP NEXT GENERATION OP07, ULTRALOW OFFSET VOLTAGE OPERATIONAL AMPLIFIER
OP77GP NEXT GENERATION OP07, ULTRALOW OFFSET VOLTAGE OPERATIONAL AMPLIFIER
OP77AJ NEXT GENERATION OP07, ULTRALOW OFFSET VOLTAGE OPERATIONAL AMPLIFIER
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
OP777AR 制造商:Analog Devices 功能描述:OP AMP PRECISION SMD SOIC8 777
OP777ARM 制造商:AD 制造商全稱:Analog Devices 功能描述:Precision Micropower Single-Supply Operational Amplifiers
OP777ARM-R2 制造商:Analog Devices 功能描述:OP Amp Single GP R-R O/P ±15V/30V 8-Pin MSOP T/R 制造商:Rochester Electronics LLC 功能描述:SINGLE PRECISION RAIL-RAIL OP AMP - Bulk
OP777ARM-REEL 制造商:Analog Devices 功能描述:OP Amp Single GP R-R O/P ±15V/30V 8-Pin MSOP T/R
OP777ARMZ 功能描述:IC OPAMP GP R-R 700KHZ 8MSOP RoHS:是 類(lèi)別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 產(chǎn)品培訓(xùn)模塊:Differential Circuit Design Techniques for Communication Applications 標(biāo)準(zhǔn)包裝:1 系列:- 放大器類(lèi)型:RF/IF 差分 電路數(shù):1 輸出類(lèi)型:差分 轉(zhuǎn)換速率:9800 V/µs 增益帶寬積:- -3db帶寬:2.9GHz 電流 - 輸入偏壓:3µA 電壓 - 輸入偏移:- 電流 - 電源:40mA 電流 - 輸出 / 通道:- 電壓 - 電源,單路/雙路(±):3 V ~ 3.6 V 工作溫度:-40°C ~ 85°C 安裝類(lèi)型:表面貼裝 封裝/外殼:16-VQFN 裸露焊盤(pán),CSP 供應(yīng)商設(shè)備封裝:16-LFCSP-VQ 包裝:剪切帶 (CT) 產(chǎn)品目錄頁(yè)面:551 (CN2011-ZH PDF) 其它名稱:ADL5561ACPZ-R7CT