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参数资料
| 型号： | AD824 |
| 厂商： | Analog Devices, Inc. |
| 英文描述： | Single Supply, Rail-to-Rail Low Power, FET-Input Op Amp |
| 中文描述： | 单电源，轨对轨低功耗，FET输入运算放大器 |
| 文件页数： | 13/16页 |
| 文件大小： | 551K |
| 代理商： | AD824 |
AD824
REV. A
–13–
3 Volt, Single Supply Stereo Headphone Driver
The AD824 exhibits good current drive and THD+N perfor-
mance, even at 3 V single supplies. At 1 kHz, total harmonic
distortion plus noise (THD+N) equals –62 dB (0.079%) for a
300 mV p-p output signal. This is comparable to other single
supply op amps that consume more power and cannot run on 3
V power supplies.
In Figure 33, each channel’s input signal is coupled via a 1
μ
F
Mylar capacitor. Resistor dividers set the dc voltage at the
noninverting inputs so that the output voltage is midway be-
tween the power supplies (+1.5 V). The gain is 1.5. Each half of
the AD824 can then be used to drive a headphone channel. A
5 Hz high-pass filter is realized by the 500
μ
F capacitors and the
headphones, which can be modeled as 32 ohm load resistors to
ground. This ensures that all signals in the audio frequency
range (20 Hz–20 kHz) are delivered to the headphones.
MYLAR
1μF
1/4
AD824
L
R
HEADPHONES
32
IMPEDANCE
4.99k
MYLAR
1μF
4.99k
1/4
AD824
10k
10k
47.5k
95.3k
47.5k
500μF
500μF
+3V
0.1μF
0.1μF
CHANNEL 1
CHANNEL 2
95.3k
Figure 33. 3 Volt Single Supply Stereo Headphone Driver
Low Dropout Bipolar Bridge Driver
The AD824 can be used for driving a 350 ohm Wheatstone
bridge. Figure 34 shows one half of the AD824 being used to
buffer the AD589—a 1.235 V low power reference. The output
350
350
350
350
V
REF
–V
S
+V
S
AD620
R
G
R2
20
–4.5V
10k
10k
10k
26.4k, 1%
R1
20
TO A/D CONVERTER
REFERENCE INPUT
AD589
49.9k
+1.235V
+5V
1μF
GND
1%
1%
1%
1/4
AD824
1/4
AD824
–V
S
+V
S
+V
S
–V
S
0.1μF
–5V
1μF
0.1μF
7
6
5
4
3
2
Figure 34. Low Dropout Bipolar Bridge Driver
of +4.5 V can be used to drive an A/D converter front end. The
other half of the AD824 is configured as a unity-gain inverter
and generates the other bridge input of –4.5 V. Resistors R1 and
R2 provide a constant current for bridge excitation. The AD620
low power instrumentation amplifier is used to condition the
differential output voltage of the bridge. The gain of the AD620
is programmed using an external resistor R
G
and determined by:
G
=
49.4
k
R
G
+
1
A 3.3 Volt/5 Volt Precision Sample-and-Hold Amplifier
In battery-powered applications, low supply voltage operational
amplifiers are required for low power consumption. Also, low
supply voltage applications limit the signal range in precision
analog circuitry. Circuits like the sample-and-hold circuit
shown in Figure 35, illustrate techniques for designing precision
analog circuitry in low supply voltage applications. To maintain
high signal-to-noise ratios (SNRs) in a low supply voltage appli-
cation requires the use of rail-to-rail, input/output operational
amplifiers. This design highlights the ability of the AD824 to oper-
ate rail-to-rail from a single +3 V/+5 V supply, with the advantages
of high input impedance. The AD824, a quad JFET-input op
amp, is well suited to S/H circuits due to its low input bias cur-
rents (3 pA, typical) and high input impedances (3
×
10
13
,
typical). The AD824 also exhibits very low supply currents so
the total supply current in this circuit is less than 2.5 mA.
3.3/5V
3.3/5V
R1
50k
R2
50k
A1
3
2
4
1
11
0.1μF
FALSE GROUND (FG)
A4
12
13
14
SAMPLE/
HOLD
A3
10
9
8
A2
5
6
7
15
14
16
10
9
11
AD824B
3.3/5V
ADG513
R5
2k
AD824C
+
–V
OUT
CH
500pF
C
500pF
FG
4
5
8
6
7
2
3
1
AD824A
AD824D
R4
2k
FG
13
FG
Figure 35. 3.3 V/5.5 V Precision Sample and Hold
In many single supply applications, the use of a false ground
generator is required. In this circuit, R1 and R2 divide the sup-
ply voltage symmetrically, creating the false ground voltage at
one-half the supply. Amplifier A1 then buffers this voltage cre-
ating a low impedance output drive. The S/H circuit is config-
ured in an inverting topology centered around this false ground
level.
相关PDF资料 |
PDF描述 |
|---|---|
| AD824AN | Single Supply, Rail-to-Rail Low Power, FET-Input Op Amp |
| AD824AR | Single Supply, Rail-to-Rail Low Power, FET-Input Op Amp |
| AD824BN | Single Supply, Rail-to-Rail Low Power, FET-Input Op Amp |
| AD824ACHIPS | Single Supply, Rail-to-Rail Low Power, FET-Input Op Amp |
| AD824AR-14 | VARISTOR 140V RMS 14MM RADIAL |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AD824_03 | 制造商:AD 制造商全称:Analog Devices 功能描述:Single Supply, Rail-to-Rail Low Power, FET-Input Op Amp |
| AD8240 | 制造商:AD 制造商全称:Analog Devices 功能描述:LED Driver/Monitor |
| AD8240YRM | 功能描述:IC LED DRIVER PWM CONTROL 8-MSOP RoHS:否 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:6,000 系列:- 恒定电流:- 恒定电压:- 拓扑:开路漏极，PWM 输出数:4 内部驱动器:是 类型 - 主要:LED 闪烁器 类型 - 次要:- 频率:400kHz 电源电压:2.3 V ~ 5.5 V 输出电压:- 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘 供应商设备封装:8-HVSON 包装:带卷 (TR) 工作温度:-40°C ~ 85°C 其它名称:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND |
| AD8240YRM-REEL | 制造商:Analog Devices 功能描述:LED DRVR 6Segment 12V/15V/18V/24V 8-Pin MSOP T/R |
| AD8240YRM-REEL7 | 制造商:Analog Devices 功能描述:LED DRVR 6Segment 12V/15V/18V/24V 8-Pin MSOP T/R |
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