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參數(shù)資料
| 型號： | OP281GRU |
| 廠商： | ANALOG DEVICES INC |
| 元件分類： | 運(yùn)動控制電子 |
| 英文描述： | Ultralow Power, Rail-to-Rail Output Operational Amplifiers |
| 中文描述： | DUAL OP-AMP, 2500 uV OFFSET-MAX, 0.105 MHz BAND WIDTH, PDSO8 |
| 封裝： | MO-153AA, TSSOP-8 |
| 文件頁數(shù)： | 13/16頁 |
| 文件大?。?/td> | 963K |
| 代理商： | OP281GRU |
REV. B
OP281/OP481
–13–
The OP281-A op amp provides about 29 dB of gain for audio
signals coming from the microphone. The gain is set by the
300 k
W
and 11 k
W
resistors. The gain bandwidth product of the
amplifier is 95 kHz, which, for the set gain of 28, yields a
–
3 dB
rolloff at 3.4 kHz. This is acceptable since telephone audio is band
limited for 300 kHz to 3 kHz signals. If higher gain is required
for the microphone, an additional gain stage should be used, as
adding any more gain to the OP281 would limit the audio band-
width. A 2.2 k
W
resistor is used to bias the electret microphone.
This resistor value may vary depending on the specifications on
the microphone being used. The output of the microphone is ac-
coupled to the noninverting terminal of the op amp. Two 1 M
W
resistors are used to provide the dc offset for single-supply use.
The OP281-B amplifier can provide up to 15 dB of gain for the
headset speaker. Incoming audio signals are ac-coupled to a
10 k
W
potentiometer that is used to adjust the volume. Again,
two 1 M
W
resistors provide the dc offset with a 1
m
F capacitor
establishing an ac ground for the volume control potentiometer.
Because the OP281 is a rail-to-rail output amplifier, it would have
difficulty driving a 600
W
speaker directly. Here, a class AB buffer
is used to isolate the load from the amplifier and also provide
the necessary current drive to the speaker. By placing the buffer
in the feedback loop of the op amp, crossover distortion can be
minimized. Q1 and Q2 should have minimum betas of 100. The
600
W
speaker is ac-coupled to the emitters to prevent any qui-
escent current from flowing in the speaker. The 1
m
F coupling
capacitor makes an equivalent high-pass filter cutoff at 265 Hz
with a 600
W
load attached. Again, this does not pose a problem,
as it is outside the frequency range for telephone audio signals.
The circuit in Figure 10 draws around 250
m
A of current. The
class AB buffer has a quiescent current of 140
m
A while roughly
100
m
A is drawn by the microphone itself. A CR2032 3V lithium
battery has a life expectancy of 160 mA hours, which means this
circuit could run continuously for 640 hours on a single battery.
SPICE Macro-Model
Single OPx81 Channel SPICE Macro-model
* 9/96, Ver. 1
*
* Copyright 1996 by Analog Devices
*
* Refer to
“
README.DOC
”
file for License Statement. Use of this
* model indicates your acceptance of the terms and provisions in the
* License Statement.
*
* Node Assignments
*
noninverting input
*
|
inverting input
*
|
|
*
|
|
*
|
|
*
|
|
*
|
|
.SUBCKT OPx81
1
2
*
* INPUT STAGE
*
Q1
4
1
3
PIX
Q2
6
7
5
PIX
I1
99
8
1.28E-6
positive supply
|
negative supply
|
|
|
|
|
|
99
50
output
|
|
45
EOS
IOS
RC1
RC2
RE1
RE2
V1
V2
D1
D2
*
* CMRR76dB,
*
ECM1 11 98
R1
C1
R2
* POLE AT 900kHz
*
EREF 98
G1
98 20
R3
20 98
C2
20 98
*
* POLE AT 500kHz
*
E2
21 98
R4
21 22
C3
22 98
*
* GAIN STAGE
*
CF
45
R5
40
G3
98
D3
40
D4
42
V3
99
V4
42
*
* OUTPUT STAGE
*
ISY
99
RS1
99
RS2
90
M1
45
M2
45
EG1
99
EG2
47
*
* MODELS
*
.MODEL POX PMOS (LEVEL=2, KP=25E-6, VTO=-0.75,
LAMBDA=0.01)
.MODEL NOX NMOS (LEVEL=2, KP=25E-6, VTO=0.75,
LAMBDA=0.01)
.MODEL PIX
PNP
(BF=200)
.MODEL DX D(IS=1E-14)
.ENDS
7
1
4
6
3
5
2
2
POLY(1)
1E-10
500E3
500E3
108
108
DC .9
DC .9
DX
DX
(12, 98) 80E-6 1
50
50
8
8
99
99
13
14
13
14
3
5
ZERO AT 1kHz
POLY(2)
1.59E6
100E-12
283
(1, 98) (2, 98) 0 .5 .5
11 12
11 12
12 98
0
(90, 0)
(4, 6)
1E6
177E-15
1
1E-6
(20, 98)
1E6
320E-15
1
40
98
40
41
40
41
50
8. 5E-12
65. 65E6
(22, 98)
DX
DX
DC 0.5
DC 0.5
4.08E-7
50
90
50
46
47
46
50
1.375E-6
10E6
10E6
99
50
POLY(1)
POLY(1)
99
50
POX L=1.5u
NOXL=1.5u
(98, 40)
(40, 98)
W=300u
W=300u
1
1
0.77
0.77
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| OP281GS | Ultralow Power, Rail-to-Rail Output Operational Amplifiers |
| OP481 | Ultralow Power, Rail-to-Rail Output Operational Amplifiers |
| OP481GRU | Ultralow Power, Rail-to-Rail Output Operational Amplifiers |
| OP481GS | Ultralow Power, Rail-to-Rail Output Operational Amplifiers |
| OP481GP | Ultralow Power, Rail-to-Rail Output Operational Amplifiers |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| OP281GRU-REEL | 制造商:Rochester Electronics LLC 功能描述:DUAL 5UA RAIL TO RAIL OP AMP - Tape and Reel 制造商:Analog Devices 功能描述: |
| OP281GRUZ-REEL | 功能描述:IC OPAMP GP R-R 105KHZ LP 8TSSOP RoHS:是 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 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 |
| OP281GS | 制造商:Analog Devices 功能描述:OP Amp Dual GP R-R O/P 制造商:Rochester Electronics LLC 功能描述:DUAL 5UA RAIL TO RAIL OP AMP - Bulk 制造商:Analog Devices 功能描述:IC OP-AMP DUAL ULOW-PWR RRO/P |
| OP281GS-REEL | 制造商:Analog Devices 功能描述:OP Amp Dual GP R-R O/P |
| OP281GS-REEL7 | 制造商:Analog Devices 功能描述:OP Amp Dual GP R-R O/P |
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