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參數資料
| 型號： | AD8554ARU |
| 廠商： | ANALOG DEVICES INC |
| 元件分類： | 運動控制電子 |
| 英文描述： | Zero-Drift, Single-Supply, Rail-to-Rail Input/Output Operational Amplifiers |
| 中文描述： | QUAD OP-AMP, 10 uV OFFSET-MAX, 1.5 MHz BAND WIDTH, PDSO14 |
| 封裝： | MO-153AB-1, TSSOP-14 |
| 文件頁數： | 12/20頁 |
| 文件大?。?/td> | 262K |
| 代理商： | AD8554ARU |
AD8551/AD8552/AD8554
–12–
REV. 0
be a specific width, but it should form a continuous loop around
both inputs. By setting the guard ring voltage equal to the volt-
age at the noninverting input, parasitic capacitance is minimized
as well. For further reduction of leakage currents, components
can be mounted to the PC board using Teflon standoff insulators.
V
OUT
V
IN
AD8552
V
OUT
V
IN
AD8552
V
OUT
V
IN
AD8552
Figure 46. Guard Ring Layout and Connections to Reduce
PC Board Leakage Currents
V
2
V+
V
REF
V
IN1
V
IN2
GUARD
RING
R
2
R
2
R
1
R
1
AD8552
V
REF
GUARD
RING
Figure 47. Top View of AD8552 SOIC Layout with
Guard Rings
Other potential sources of offset error are thermoelectric voltages
on the circuit board. This voltage, also called Seebeck voltage,
occurs at the junction of two dissimilar metals and is proportional
to the temperature of the junction. The most common metallic
junctions on a circuit board are solder-to-board trace and solder-
to-component lead. Figure 48 shows a cross-section diagram view
of the thermal voltage error sources. If the temperature of the PC
board at one end of the component (T
A1
) is different from the
temperature at the other end (T
A2
), the Seebeck voltages will not
be equal, resulting in a thermal voltage error.
This thermocouple error can be reduced by using dummy com-
ponents to match the thermoelectric error source. Placing the
dummy component as close as possible to its partner will ensure
both Seebeck voltages are equal, thus canceling the thermo-
couple error. Maintaining a constant ambient temperature on
the circuit board will further reduce this error. The use of a
ground plane will help distribute heat throughout the board and
will also reduce EMI noise pickup.
SURFACE MOUNT
COMPONENT
COMPONENT
LEAD
SOLDER
PC BOARD
COPPER
TRACE
V
SC2
2
+
+
2
V
TS2
T
A2
T
A1
V
SC1
2
+
+
2
V
TS1
IF T
A1
fi
T
A2
, THEN
V
TS1
+ V
SC1
fi
V
TS2
+ V
SC2
Figure 48. Mismatch in Seebeck Voltages Causes a
Thermoelectric Voltage Error
V
OUT
V
IN
AD855x
A
V
= 1 + (R
F
/R
1
)
R
1
R
F
R
S
= R
1
NOTE: R
SHOULD BE PLACED IN CLOSE PROXIMITY AND
ALIGNMENT TO R
1
TO BALANCE SEEBECK VOLTAGES
Figure 49. Using Dummy Components to Cancel
Thermoelectric Voltage Errors
1/f Noise Characteristics
Another advantage of autozero amplifiers is their ability to cancel
flicker noise. Flicker noise, also known as 1/f noise, is noise inher-
ent in the physics of semiconductor devices and increases 3 dB
for every octave decrease in frequency. The 1/f corner frequency
of an amplifier is the frequency at which the flicker noise is equal
to the broadband noise of the amplifier. At lower frequencies,
flicker noise dominates, causing higher degrees of error for sub-
Hertz frequencies or dc precision applications.
Because the AD855x amplifiers are self-correcting op amps,
they do not have increasing flicker noise at lower frequencies.
In essence, low frequency noise is treated as a slowly varying
offset error and is greatly reduced as a result of autocorrection.
The correction becomes more effective as the noise frequency
approaches dc, offsetting the tendency of the noise to increase
exponentially as frequency decreases. This allows the AD855x
to have lower noise near dc than standard low-noise amplifiers
that are susceptible to 1/f noise.
Intermodulation Distortion
The AD855x can be used as a conventional op amp for gain/
bandwidth combinations up to 1.5 MHz. The autozero correc-
tion frequency of the device is fixed at 4 kHz. Although a trace
amount of this frequency will feed through to the output, the
amplifier can be used at much higher frequencies. Figure 50
shows the spectral output of the AD8552 with the amplifier
configured for unity gain and the input grounded.
The 4 kHz autozero clock frequency appears at the output with
less than 2
μ
V of amplitude. Harmonics are also present, but at
reduced levels from the fundamental autozero clock frequency.
The amplitude of the clock frequency feedthrough is proportional
to the closed-loop gain of the amplifier. Like other autocorrection
amplifiers, at higher gains there will be more clock frequency
feedthrough. Figure 51 shows the spectral output with the ampli-
fier configured for a gain of 60 dB.
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| AD8551AR | Zero-Drift, Single-Supply, Rail-to-Rail Input/Output Operational Amplifiers |
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| AD8552AR | Zero-Drift, Single-Supply, Rail-to-Rail Input/Output Operational Amplifiers |
| AD8552ARU | Zero-Drift, Single-Supply, Rail-to-Rail Input/Output Operational Amplifiers |
| AD8554AR | Zero-Drift, Single-Supply, Rail-to-Rail Input/Output Operational Amplifiers |
相關代理商/技術參數 |
參數描述 |
|---|---|
| AD8554ARU-REEL | 制造商:Analog Devices 功能描述:SP Amp Zero Drift Amplifier Quad R-R I/O 5V 14-Pin TSSOP T/R 制造商:Rochester Electronics LLC 功能描述:QUAD PRECISION RAIL-RAIL CHOPPER OP AMP - Tape and Reel |
| AD8554ARUZ | 功能描述:IC OPAMP CHOPPER R-R 14TSSOP RoHS:是 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 標準包裝:2,500 系列:- 放大器類型:通用 電路數:4 輸出類型:- 轉換速率:0.6 V/µs 增益帶寬積:1MHz -3db帶寬:- 電流 - 輸入偏壓:45nA 電壓 - 輸入偏移:2000µV 電流 - 電源:1.4mA 電流 - 輸出 / 通道:40mA 電壓 - 電源，單路/雙路(±):3 V ~ 32 V，±1.5 V ~ 16 V 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:14-TSSOP（0.173"，4.40mm 寬） 供應商設備封裝:14-TSSOP 包裝:帶卷 (TR) 其它名稱:LM324ADTBR2G-NDLM324ADTBR2GOSTR |
| AD8554ARUZ | 制造商:Analog Devices 功能描述:IC OP-AMP 1.5MHZ 制造商:Analog Devices 功能描述:IC, OP-AMP, 1.5MHZ, 0.4V/ us, TSSOP-14 |
| AD8554ARUZ | 制造商:Analog Devices 功能描述:IC OP AMP 1.5MHZ 0.4V/US 14TSSOP |
| AD8554ARUZ-REEL | 功能描述:IC OPAMP CHOPPER R-R 14TSSOP RoHS:是 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 標準包裝:73 系列:Over-The-Top® 放大器類型:通用 電路數:4 輸出類型:滿擺幅 轉換速率:0.07 V/µs 增益帶寬積:200kHz -3db帶寬:- 電流 - 輸入偏壓:1nA 電壓 - 輸入偏移:285µV 電流 - 電源:50µA 電流 - 輸出 / 通道:25mA 電壓 - 電源，單路/雙路(±):2 V ~ 44 V，±1 V ~ 22 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:16-WFDFN 裸露焊盤 供應商設備封裝:16-DFN-EP（5x3） 包裝:管件 |
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