ADA4841-2YCPZ-RL [ADI]

Low Power, Low Noise and Distortion ail-to-Rail Output Amplifiers; 低功耗,低噪声和失真AIL到轨输出放大器
ADA4841-2YCPZ-RL
型号: ADA4841-2YCPZ-RL
厂家: ADI    ADI
描述:

Low Power, Low Noise and Distortion ail-to-Rail Output Amplifiers
低功耗,低噪声和失真AIL到轨输出放大器

运算放大器 放大器电路 光电二极管
文件: 总21页 (文件大小:631K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
Low Power, Low Noise and Distortion,  
Rail-to-Rail Output Amplifiers  
ADA4841-1/ADA4841-2  
CONNECTION DIAGRAMS  
FEATURES  
Low power: 1.1 mA/amp  
Low wideband noise  
2.1 nV/√Hz  
1.4 pA/√Hz  
Low 1/f noise  
ADA4841-1  
TOP VIEW  
(Not to Scale)  
NC  
–IN  
+IN  
1
2
3
4
8
7
6
5
POWER DOWN  
+V  
S
V
OUT  
–V  
NC  
S
7 nV/√Hz @ 10 Hz  
13 pA/√Hz @ 10 Hz  
Figure 1. 8-Lead SOIC (R)  
ADA4841-1  
Low distortion: −105 dBc @ 100 kHz, VO = 2 V p-p  
High speed  
80 MHz, −3 dB bandwidth (G = +1)  
12 V/μs slew rate  
175 ns settling time to 0.1%  
Low offset voltage: 0.3 mV maximum  
Rail-to-rail output  
V
1
2
3
6
5
4
+V  
S
OUT  
–V  
POWER DOWN  
–IN  
S
+IN  
Figure 2. 6-Lead SOT-23 (RJ)  
Power down  
ADA4841-2  
Wide supply range: 2.7 V to 12 V  
OUT1  
IN1  
+IN1  
1
2
3
4
8
7
6
5
+V  
S
OUT2  
IN2  
+IN2  
APPLICATIONS  
V  
S
Low power, low noise signal processing  
Battery-powered instrumentation  
16-bit PulSAR® ADC drivers  
TOP VIEW  
(Not to Scale)  
NOTES  
1. FOR 8-LEAD LFCSP_WD, CONNECT  
EXPOSED PADDLE TO GND.  
Figure 3. 8-Lead MSOP (RM), 8-Lead SOIC_N (R), and 8-Lead LFCSP_WD (CP)  
GENERAL DESCRIPTION  
The ADA4841-1/ADA4841-2 are unity gain stable, low noise  
and distortion, rail-to-rail output amplifiers that have a quiescent  
current of 1.5 mA maximum. In spite of their low power  
consumption, these amplifiers offer low wideband voltage  
noise performance of 2.1 nV/Hz and 1.4 pA/Hz current noise,  
along with excellent spurious-free dynamic range (SFDR) of  
−105 dBc at 100 kHz. To maintain a low noise environment at  
lower frequencies, the amplifiers have low 1/f noise of 7 nV/Hz  
and 13 pA/Hz at 10 Hz.  
The ADA4841-1/ADA4841-2 packages feature RoHS compliant  
lead finishes. The amplifiers are rated to work over the  
industrial temperature range (−40°C to +125°C).  
–30  
V
= ±5V  
S
G = +1  
–40  
–50  
–60  
–70  
2V p-p THIRD  
The ADA4841-1/ADA4841-2 output can swing to less than  
50 mV of either rail. The input common-mode voltage range  
extends down to the negative supply. The ADA4841-1/  
ADA4841-2 can drive up to 10 pF of capacitive load with  
minimal peaking.  
–80  
–90  
2V p-p SECOND  
–100  
–110  
–120  
The ADA4841-1/ADA4841-2 provide the performance required  
to efficiently support emerging 16-bit to 18-bit ADCs and are  
ideal for portable instrumentation, high channel count, industrial  
measurement, and medical applications. The ADA4841-1/  
ADA4841-2 are ideally suited to drive the AD7685/AD7686,  
16-bit PulSAR ADCs.  
0.01  
0.1  
FREQUENCY (MHz)  
1
Figure 4. Harmonic Distortion  
Rev. E  
Information furnished by Analog Devices is believed to be accurate and reliable. However, no  
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other  
rights of third parties that may result from its use. Specifications subject to change without notice. No  
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.  
Trademarks and registeredtrademarks arethe property of their respective owners.  
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.  
Tel: 781.329.4700 www.analog.com  
Fax: 781.461.3113 ©2005–2010 Analog Devices, Inc. All rights reserved.  
 
 
 
IMPORTANT LINKS for the ADA4841-1_4841-2*  
Last content update 08/17/2013 01:21 pm  
DOCUMENTATION  
PARAMETRIC SELECTION TABLES  
Find Similar Products By Operating Parameters  
AN-931: Understanding PulSAR ADC Support Circuitry  
AN-649: Using the Analog Devices Active Filter Design Tool  
AN-581: Biasing and Decoupling Op Amps in Single Supply Apps  
High Speed Amplifiers Selection Table  
AN-402: Replacing Output Clamping Op Amps with Input Clamping  
Amps  
EVALUATION KITS & SYMBOLS & FOOTPRINTS  
View the Evaluation Board and Kits page for the ADA4841-1  
View the Evaluation Board and Kits page for the ADA4841-2  
Symbols and Footprints for the ADA4841-1  
AN-417: Fast Rail-to-Rail Operational Amplifiers Ease Design  
Constraints in Low Voltage High Speed Systems  
AN-202: An IC Amplifier User’s Guide to Decoupling, Grounding, and  
Making Things Go Right for a Change  
MT-060: Choosing Between Voltage Feedback and Current Feedback  
Op Amps  
Symbols and Footprints for the ADA4841-2  
MT-059: Compensating for the Effects of Input Capacitance on VFB  
and CFB Op Amps Used in Current-to-Voltage Converters  
MT-058: Effects of Feedback Capacitance on VFB and CFB Op Amps  
MT-056: High Speed Voltage Feedback Op Amps  
DESIGN TOOLS, MODELS, DRIVERS & SOFTWARE  
dBm/dBu/dBv Calculator  
MT-053: Op Amp Distortion: HD, THD, THD + N, IMD, SFDR, MTPR  
MT-052: Op Amp Noise Figure: Don't Be Mislead  
Power Dissipation vs Die Temp  
ADIsimOpAmp™  
MT-050: Op Amp Total Output Noise Calculations for Second-Order  
System  
Analog Filter Wizard 2.0  
MT-049: Op Amp Total Output Noise Calculations for Single-Pole  
OpAmp Stability  
System  
ADA4841 SPICE Macro Model, Rev 0, 2/2007  
MT-048: Op Amp Noise Relationships: 1/f Noise, RMS Noise, and  
Equivalent Noise Bandwidth  
MT-047: Op Amp Noise  
MT-033: Voltage Feedback Op Amp Gain and Bandwidth  
MT-032: Ideal Voltage Feedback (VFB) Op Amp  
A Stress-Free Method for Choosing High-Speed Op Amps  
FOR THE ADA4841-1:  
DESIGN SUPPORT  
Submit your support request here:  
Linear and Data Converters  
Embedded Processing and DSP  
Telephone our Customer Interaction Centers toll free:  
CN-0255 A Complete Single-Supply, 16-Bit, 100 kSPS PulSAR ADC  
Americas:  
Europe:  
China:  
1-800-262-5643  
00800-266-822-82  
4006-100-006  
System Dissipates 8 mW (for the ADA4841-1)  
UG-127: Universal Evaluation Board for High Speed Op Amps in  
SOT-23-5/SOT-23-6 Packages  
India:  
1800-419-0108  
8-800-555-45-90  
Russia:  
UG-101: Evaluation Board User Guide  
Quality and Reliability  
Lead(Pb)-Free Data  
FOR THE ADA4841-2:  
UG-129: Evaluation Board User Guide  
UG-128: Universal Evaluation Board for Dual High Speed Op Amps in  
SOIC Packages  
SAMPLE & BUY  
ADA4841-1  
ADA4841-2  
DESIGN COLLABORATION COMMUNITY  
View Price & Packaging  
Request Evaluation Board  
Request Samples Check Inventory & Purchase  
Collaborate Online with the ADI support team and other designers  
about select ADI products.  
Find Local Distributors  
Follow us on Twitter: www.twitter.com/ADI_News  
Like us on Facebook: www.facebook.com/AnalogDevicesInc  
* This page was dynamically generated by Analog Devices, Inc. and inserted into this data sheet.  
Note: Dynamic changes to the content on this page (labeled 'Important Links') does not  
constitute a change to the revision number of the product data sheet.  
This content may be frequently modified.  
ADA4841-1/ADA4841-2  
TABLE OF CONTENTS  
Features .............................................................................................. 1  
Headroom Considerations........................................................ 14  
Capacitance Drive ...................................................................... 15  
Input Protection ......................................................................... 15  
Power-Down Operation............................................................ 16  
Applications Information.............................................................. 17  
Typical Performance Values...................................................... 17  
16-Bit ADC Driver..................................................................... 17  
Reconstruction Filter ................................................................. 17  
Layout Considerations............................................................... 18  
Ground Plane.............................................................................. 18  
Power Supply Bypassing............................................................ 18  
Outline Dimensions....................................................................... 19  
Ordering Guide .......................................................................... 20  
Applications....................................................................................... 1  
Connection Diagrams...................................................................... 1  
General Description......................................................................... 1  
Revision History ............................................................................... 2  
Specifications..................................................................................... 3  
Absolute Maximum Ratings............................................................ 6  
Thermal Resistance ...................................................................... 6  
Maximum Power Dissipation ..................................................... 6  
ESD Caution.................................................................................. 6  
Typical Performance Characteristics ............................................. 7  
Theory of Operation ...................................................................... 13  
Amplifier Description................................................................ 13  
DC Errors .................................................................................... 13  
Noise Considerations................................................................. 13  
REVISION HISTORY  
12/10—Rev. D to Rev. E  
Changes to Negative Power Supply Rejection Ration Conditions ..3  
Changes to Ordering Guide .......................................................... 20  
Changes to Figure 6...........................................................................7  
Changes to Figure 12, Figure 13, Figure 15, and Figure 16..........8  
Deleted Figure 25; Renumber Sequentially ................................ 10  
Changes to Figure 24 and Figure 28............................................. 10  
Changes to Figure 31...................................................................... 11  
Inserted Figure 37; Renumber Sequentially................................ 12  
Changes to Amplifier Description Section and Figure 39........ 13  
Changed DC Performance Considerations Section  
to DC Errors Section...................................................................... 13  
Changes to Noise Considerations Section .................................. 14  
Changes to Headroom Considerations Section and Figure 39 15  
Changes to Power-Down Operation Section.............................. 16  
Changes to 16-Bit ADC Driver Section,  
1/10—Rev. C to Rev. D  
Added LFCSP Package.......................................................Universal  
Changes to Operating Temperature Range Parameter, Table 4.. 6  
Updated Outline Dimensions....................................................... 19  
Changes to Ordering Guide .......................................................... 20  
3/06—Rev. B to Rev. C  
Added SOT-23 Package .....................................................Universal  
Changes to General Description .................................................... 1  
Changes to Table 1............................................................................ 3  
Changes to Table 2............................................................................ 4  
Changes to Table 3............................................................................ 5  
Changes to Input Protection Section ........................................... 15  
Changes to Ordering Guide .......................................................... 20  
Figure 48, and Figure 49 ................................................................ 17  
Changes to Power Supply Bypassing Section ............................. 18  
Updated Outline Dimensions....................................................... 19  
Changes to Ordering Guide.......................................................... 20  
9/05—Rev. 0 to Rev. A  
10/05—Rev. A to Rev. B  
Changes to Features ..........................................................................1  
Changes to Figure 2...........................................................................1  
Changes to Figure 12.........................................................................8  
Changes to Figure 40...................................................................... 14  
Changes to Headroom Considerations Section ......................... 15  
Added ADA4841-2.............................................................Universal  
Changes to General Description and Features ............................. 1  
Changes to Table 1............................................................................ 3  
Changes to Table 2............................................................................ 4  
Changes to Table 3............................................................................ 5  
Changes to Table 4, Table 5, and Figure 4 ..................................... 6  
7/05—Revision 0: Initial Version  
Rev. E | Page 2 of 20  
 
ADA4841-1/ADA4841-2  
SPECIFICATIONS  
TA = 25°C, VS = 5 V, RL = 1 kΩ, Gain = +1, unless otherwise noted.  
Table 1.  
Parameter  
DYNAMIC PERFORMANCE  
−3 dB Bandwidth  
Conditions  
Min  
58  
Typ  
Max  
Unit  
VO = 0.02 V p-p  
VO = 2 V p-p  
G = +1, VO = 9 V step, RL = 1 kΩ  
G = +1, VO = 8 V step  
G = +1, VO = 8 V step  
80  
3
13  
650  
1000  
MHz  
MHz  
V/μs  
ns  
Slew Rate  
Settling Time to 0.1%  
Settling Time to 0.01%  
NOISE/HARMONIC PERFORMANCE  
Harmonic Distortion HD2/HD3  
12  
ns  
fC = 100 kHz, VO = 2 V p-p, G = +1  
fC = 1 MHz, VO = 2 V p-p  
f = 100 kHz  
−111/−105  
−80/−67  
2.1  
dBc  
dBc  
nV/√Hz  
pA/√Hz  
Input Voltage Noise  
Input Current Noise  
f = 100 kHz  
1.4  
DC PERFORMANCE  
Input Offset Voltage  
Input Offset Voltage Drift  
Input Bias Current  
Input Offset Current  
Open-Loop Gain  
40  
1
3
0.1  
120  
300  
μV  
μV/°C  
μA  
μA  
dB  
5.3  
0.5  
VO = 4 V  
103  
INPUT CHARACTERISTICS  
Input Resistance, Common Mode  
Input Resistance, Differential Mode  
Input Capacitance, Common Mode  
Input Capacitance, Differential Mode  
Input Common-Mode Voltage Range  
Common-Mode Rejection Ratio (CMRR)  
MATCHING CHARACTERISTICS (ADA4841-2)  
Input Offset Voltage  
90  
25  
1
MΩ  
kΩ  
pF  
pF  
V
3
−5.1  
95  
+4  
VCM = Δ 4 V  
115  
dB  
70  
60  
μV  
nA  
Input Bias Current  
POWER DOWN PIN (ADA4841-1)  
POWER DOWN Voltage  
POWER DOWN Voltage  
Input Current  
Enabled  
>3.6  
<3.2  
V
V
Power down  
Enable  
POWER DOWN = +5 V  
POWER DOWN = −5 V  
1
2
μA  
μA  
Power Down  
−13  
−30  
Switching Speed  
Enable  
Power Down  
1
40  
μs  
μs  
OUTPUT CHARACTERISTICS  
Output Voltage Swing  
Output Current Limit  
G > +1  
4.9  
4.955  
30  
60  
V
Sourcing, VIN = +VS , RL = 50 Ω to GND  
Sinking, VIN = −VS , RL = 50 Ω to GND  
30% overshoot  
mA  
mA  
pF  
Capacitive Load Drive  
POWER SUPPLY  
15  
Operating Range  
Quiescent Current/Amplifier  
2.7  
12  
1.5  
90  
V
POWER DOWN = +5 V  
1.2  
40  
mA  
μA  
dB  
dB  
POWER DOWN = −5 V  
Positive Power Supply Rejection Ratio  
Negative Power Supply Rejection Ratio  
+VS = +5 V to +6 V, −VS = −5 V  
+VS = +5 V, −VS = −5 V to −6 V  
95  
96  
110  
120  
Rev. E | Page 3 of 20  
 
ADA4841-1/ADA4841-2  
TA = 25°C, VS = 5 V, RL = 1 kΩ, Gain = +1, VCM = 2.5 V, unless otherwise noted.  
Table 2.  
Parameter  
DYNAMIC PERFORMANCE  
−3 dB Bandwidth  
Conditions  
Min  
54  
Typ  
Max Unit  
VO = 0.02 V p-p  
VO = 2 V p-p  
G = +1, VO = 4 V step, RL = 1 kΩ  
G = +1, VO = 2 V step  
G = +1, VO = 2 V step  
80  
3
12  
175  
550  
MHz  
MHz  
V/μs  
ns  
Slew Rate  
Settling Time to 0.1%  
Settling Time to 0.01%  
NOISE/HARMONIC PERFORMANCE  
Harmonic Distortion HD2/HD3  
10  
ns  
fC = 100 kHz, VO = 2 V p-p  
fC = 1 MHz, VO = 2 V p-p  
f = 100 kHz  
f = 100 kHz  
f = 100 kHz  
−109/−105  
−78/−66  
2.1  
1.4  
−117  
dBc  
dBc  
nV/√Hz  
pA/√Hz  
dB  
Input Voltage Noise  
Input Current Noise  
Crosstalk  
DC PERFORMANCE  
Input Offset Voltage  
Input Offset Voltage Drift  
Input Bias Current  
Input Offset Current  
Open-Loop Gain  
40  
1
3
0.1  
124  
300  
μV  
μV/°C  
μA  
μA  
dB  
5.3  
0.4  
VO = 0.5 V to 4.5 V  
103  
INPUT CHARACTERISTICS  
Input Resistance, Common Mode  
Input Resistance, Differential Mode  
Input Capacitance, Common Mode  
Input Capacitance, Differential Mode  
Input Common-Mode Voltage Range  
Common-Mode Rejection Ratio (CMRR)  
MATCHING CHARACTERISTICS (ADA4841-2)  
Input Offset Voltage  
90  
25  
1
MΩ  
kΩ  
pF  
pF  
V
3
−0.1  
88  
+4  
VCM = Δ 1.5 V  
115  
dB  
70  
70  
μV  
nA  
Input Bias Current  
POWER DOWN PIN (ADA4841-1)  
POWER DOWN Voltage  
POWER DOWN Voltage  
Input Current  
Enabled  
>3.6  
<3.2  
Power down  
V
Enable  
POWER DOWN = 5 V  
POWER DOWN = 0 V  
1
2
μA  
μA  
Power Down  
−13  
−30  
Switching Speed  
Enable  
Power Down  
1
40  
μs  
μs  
OUTPUT CHARACTERISTICS  
Output Voltage Swing  
Output Current Limit  
G > +1  
0.08 to 4.92  
0.029 to 4.974  
V
Sourcing, VIN = +VS, RL = 50 Ω to VCM  
Sinking, VIN = −VS, RL = 50 Ω to VCM  
30% overshoot  
30  
60  
15  
mA  
mA  
pF  
Capacitive Load Drive  
POWER SUPPLY  
Operating Range  
Quiescent Current/Amplifier  
2.7  
12  
1.4  
70  
V
POWER DOWN = 5 V  
1.1  
35  
mA  
μA  
dB  
dB  
POWER DOWN = 0 V  
Positive Power Supply Rejection Ratio  
Negative Power Supply Rejection Ratio  
+VS = +5 V to +6 V, −VS = 0 V  
+VS = +5 V, −VS = 0 V to −1 V  
95  
96  
110  
120  
Rev. E | Page 4 of 20  
ADA4841-1/ADA4841-2  
TA = 25°C, VS = 3 V, RL = 1 kΩ, Gain =+1, VCM = 1.5 V, unless otherwise noted.  
Table 3.  
Parameter  
Conditions  
Min  
Typ  
Max Unit  
DYNAMIC PERFORMANCE  
−3 dB Bandwidth  
Slew Rate  
Settling Time to 0.1%  
Settling Time to 0.01%  
NOISE/HARMONIC PERFORMANCE  
Harmonic Distortion HD2/HD3  
VO = 0.02 V p-p  
52  
10  
80  
12  
120  
250  
MHz  
V/μs  
ns  
G = +1, VO = 2 V step, RL = 1 kΩ  
G = +1, VO = 1 V step  
G = +1, VO = 1 V step  
ns  
fC = 100 kHz, VO = 1 V p-p  
fC = 1 MHz, VO = 1 V p-p  
f = 100 kHz  
−97/−100  
−79/−80  
2.1  
dBc  
dBc  
nV/√Hz  
Input Voltage Noise  
Input Current Noise  
f = 100 kHz  
1.4  
pA/√Hz  
DC PERFORMANCE  
Input Offset Voltage  
Input Offset Voltage Drift  
Input Bias Current  
Input Offset Current  
Open-Loop Gain  
40  
1
3
0.1  
123  
300  
μV  
μV/°C  
μA  
μA  
dB  
5.3  
0.5  
VO = 0.5 V to 2.5 V  
101  
INPUT CHARACTERISTICS  
Input Resistance, Common Mode  
Input Resistance, Differential Mode  
Input Capacitance, Common Mode  
Input Capacitance, Differential Mode  
Input Common-Mode Voltage Range  
Common-Mode Rejection Ratio (CMRR)  
MATCHING CHARACTERISTICS (ADA4841-2)  
Input Offset Voltage  
90  
25  
1
MΩ  
kΩ  
pF  
pF  
V
3
−0.1  
86  
+2  
VCM = Δ 0.4 V  
115  
dB  
70  
60  
μV  
nA  
Input Bias Current  
POWER DOWN PIN (ADA4841-1)  
POWER DOWN Voltage  
POWER DOWN Voltage  
Input Current  
Enabled  
>1.6  
<1.2  
Power down  
V
Enable  
POWER DOWN = 3 V  
POWER DOWN = 0 V  
1
2
μA  
μA  
Power Down  
−10  
−30  
Switching Speed  
Enable  
Power Down  
1
40  
μs  
μs  
OUTPUT CHARACTERISTICS  
Output Voltage Swing  
Output Current Limit  
G > +1  
0.045 to 2.955  
0.023 to 2.988  
V
Sourcing, VIN = +VS, RL = 50 Ω to VCM  
Sinking, VIN = −VS, RL = 50 Ω to VCM  
30% overshoot  
30  
60  
30  
mA  
mA  
pF  
Capacitive Load Drive  
POWER SUPPLY  
Operating Range  
Quiescent Current/Amplifier  
2.7  
12  
1.3  
60  
V
POWER DOWN = 3 V  
1.1  
25  
mA  
μA  
dB  
dB  
POWER DOWN = 0 V  
Positive Power Supply Rejection Ratio  
Negative Power Supply Rejection Ratio  
+VS = +3 V to +4 V, −VS = 0 V  
+VS = +3 V, −VS = 0 V to −1 V  
95  
96  
110  
120  
Rev. E | Page 5 of 20  
ADA4841-1/ADA4841-2  
ABSOLUTE MAXIMUM RATINGS  
Table 4.  
PD = Quiescent Power + (Total Drive Power Load Power)  
Parameter  
Rating  
2
VS VOUT  
VOUT  
RL  
PD =  
(
VS ×IS  
)
+
×
Supply Voltage  
Power Dissipation  
12.6 V  
2
RL  
See Figure 5  
−VS − 0.5 V to +VS + 0.5 V  
±1.8 V  
−65°C to +125°C  
−40°C to +125°C  
JEDEC J-STD-20  
150°C  
Common-Mode Input Voltage  
Differential Input Voltage  
Storage Temperature Range  
Operating Temperature Range  
Lead Temperature  
RMS output voltages should be considered. If RL is referenced  
to −VS, as in single-supply operation, the total drive power is  
VS × IOUT. If the rms signal levels are indeterminate, consider the  
worst case, when VOUT = VS/4 for RL to midsupply.  
2
(
VS/4  
)
RL  
Junction Temperature  
PD = VS ×IS +  
( )  
Stresses above those listed under Absolute Maximum Ratings  
may cause permanent damage to the device. This is a stress  
rating only; functional operation of the device at these or any  
other conditions above those indicated in the operational  
section of this specification is not implied. Exposure to absolute  
maximum rating conditions for extended periods may affect  
device reliability.  
In single-supply operation with RL referenced to −VS, worst case  
is VOUT = VS/2.  
Airflow increases heat dissipation, effectively reducing θJA.  
In addition, more metal directly in contact with the package  
leads and through holes under the device reduces θJA.  
Figure 5 shows the maximum safe power dissipation in the  
package vs. the ambient temperature for the 8-lead SOIC_N  
(125°C/W), the 6-lead SOT-23 (170°C/W), 8-lead MSOP  
(145°C/W), and 8-lead LFCSP_WD (103°C/W) on a JEDEC  
standard 4-layer board. θJA values are approximations.  
THERMAL RESISTANCE  
θJA is specified for the worst-case conditions, that is, θJA is  
specified for device soldered in circuit board for surface-mount  
packages.  
Table 5. Thermal Resistance  
2.0  
Package Type  
8-lead SOIC_N  
6-Lead SOT-23  
8-lead MSOP  
θJA  
Unit  
°C/W  
°C/W  
°C/W  
°C/W  
125  
170  
130  
103  
LFCSP  
1.5  
8-Lead LFCSP_WD  
SOIC  
MSOP  
1.0  
MAXIMUM POWER DISSIPATION  
The maximum safe power dissipation for the ADA4841-1/  
ADA4841-2 is limited by the associated rise in junction  
temperature (TJ) on the die. At approximately 150°C, which is  
the glass transition temperature, the plastic changes its  
properties. Even temporarily exceeding this temperature limit  
may change the stresses that the package exerts on the die,  
permanently shifting the parametric performance of the  
amplifiers. Exceeding a junction temperature of 150°C for an  
extended period can result in changes in silicon devices,  
potentially causing degradation or loss of functionality.  
SOT-23  
0.5  
0
–55 –45 –35 –25 –15 –5  
5
15 25 35 45 55 65 75 85 95 105 115 125  
AMBIENT TEMPERATURE (°C)  
Figure 5. Maximum Power Dissipation vs. Temperature for a 4-Layer Board  
ESD CAUTION  
The power dissipated in the package (PD) is the sum of the  
quiescent power dissipation and the power dissipated in the die  
due to the amplifiers drive at the output. The quiescent power is  
the voltage between the supply pins (VS) times the quiescent  
current (IS).  
Rev. E | Page 6 of 20  
 
 
 
 
 
ADA4841-1/ADA4841-2  
TYPICAL PERFORMANCE CHARACTERISTICS  
RL = 1 kΩ, unless otherwise noted.  
3
3
0
V
V
= 5V  
= 20mV p-p  
V
V
= 2V pp  
= 5V  
S
OUT  
G = +1  
–40°C  
+25°C  
IN  
S
G = +1  
0
–3  
G = +10  
+125°C  
G = +2  
–3  
–6  
–9  
–6  
–9  
–12  
0.1  
1
10  
0.1  
1
10  
FREQUENCY (MHz)  
100  
FREQUENCY (MHz)  
Figure 6. Large Signal Frequency Response vs. Gain  
Figure 9. Small Signal Frequency Response vs. Temperature  
6
3
2
1
V
= 20mV p-p  
V
= 20mV p-p  
IN  
20pF  
WITH  
100Ω SNUBBER  
IN  
20pF  
V
= +5V  
S
G = +1  
= 5V  
G = +1  
V = ±5V  
S
V
= +3V  
S
V
S
0
–1  
–2  
–3  
–4  
–5  
–6  
0
0pF  
10pF  
–3  
–6  
–9  
0.1  
1
10  
100  
0.1  
1
10  
FREQUENCY (MHz)  
100  
FREQUENCY (MHz)  
Figure 10. Small Signal Frequency Response vs. Supply Voltage  
Figure 7. Small Signal Frequency Response vs. Capacitive Load  
3
3
V
V
= 20mV p-p  
= 5V  
V = ±5V  
S
G = +1  
IN  
S
G = –1  
G = +1  
10mV p-p  
0
–3  
G = +10  
0
–3  
–6  
–9  
2V p-p  
400mV p-p  
20mV p-p  
–6  
100mV p-p  
–9  
–12  
0.1  
0.1  
1
10  
FREQUENCY (MHz)  
100  
1
10  
FREQUENCY (MHz)  
100  
Figure 8. Small Signal Frequency Response vs. Gain  
Figure 11. Frequency Response for Various VOUT  
Rev. E | Page 7 of 20  
 
ADA4841-1/ADA4841-2  
–30  
–40  
140  
0
V
= 5V  
V
= 2V p-p  
S
OUT  
G = +2  
MAGNITUDE  
120  
100  
80  
–20  
–40  
–60  
–80  
–100  
–120  
–140  
–160  
–50  
+5V SECOND  
–60  
PHASE  
–70  
60  
+3V SECOND  
–80  
+3V THIRD  
40  
–90  
–100  
–110  
–120  
–130  
20  
±5V THIRD  
+5V THIRD  
0
–20  
10  
±5V SECOND  
100  
1k  
10k  
100k  
1M  
10M  
100M  
FREQUENCY (Hz)  
0.01  
0.1  
FREQUENCY (MHz)  
1
Figure 15. Harmonic Distortion vs. Frequency for Various Supplies  
Figure 12. Open-Loop Gain and Phase vs. Frequency  
–30  
–40  
10  
V
V
= + 5V  
OUT  
S
= 2V p-p  
V = ±5V  
S
–50  
G = +5 THIRD  
–60  
–70  
–80  
G = +2 SECOND  
G = +5 SECOND  
–90  
–100  
–110  
–120  
–130  
G = +1 SECOND  
G = +1 THIRD  
G = +2 THIRD  
0.01  
0.1  
1
1
10  
100  
1k  
10k  
100k  
1M  
10M  
FREQUENCY (MHz)  
FREQUENCY (Hz)  
Figure 16. Voltage Noise vs. Frequency  
Figure 13. Harmonic Distortion vs. Frequency for Various Gains  
–30  
100  
10  
1
V
= ±5V  
S
V
= ±5V  
G = +1  
S
–40  
–50  
8V p-p SECOND  
8V p-p THIRD  
–60  
–70  
4V p-p THIRD  
–80  
4V p-p SECOND  
–90  
–100  
–110  
–120  
2V p-p THIRD  
2V p-p SECOND  
0.01  
0.1  
1
0.1  
10  
1M  
100k  
100  
1k  
10k  
FREQUENCY (MHz)  
FREQUENCY (Hz)  
Figure 14. Harmonic Distortion vs. Frequency for Various Output Voltages  
Figure 17. Current Noise vs. Frequency  
Rev. E | Page 8 of 20  
ADA4841-1/ADA4841-2  
55  
50  
45  
40  
35  
30  
25  
20  
15  
10  
5
0.25  
0.24  
0.23  
0.22  
0.21  
0.20  
0.19  
COUNT = 190  
G = +2  
TIME = 50ns/DIV  
V
= +3V  
S
x = 0.36μV/°C  
σ
= 1.21μV/°C  
V
= +5V  
S
V
= ±5V  
S
0
–5  
–4  
–2  
0
2
4
6
OFFSET DRIFT DISTRIBUTION (μV/°C)  
Figure 18. Input Offset Voltage Drift Distribution  
Figure 21. Small Signal Transient Response for Various Supplies  
10  
0.15  
G = +2  
V = 20mV p-p  
IN  
G = +1  
V
= 5V  
S
9
8
7
6
5
4
3
2
1
0
TIME = 50ns/DIV  
0.14  
0.13  
0.12  
0.11  
0.10  
0.09  
0pF  
10pF  
20pF  
47pF  
0
1
2
3
4
5
V
(V)  
IN  
Figure 19. Nonlinearity vs. VIN  
Figure 22. Small Signal Transient Response for Various Capacitive Loads  
100  
80  
0.130  
G = +1  
TIME = 50ns/DIV  
V
= ±5  
S
V
= 3V  
S
0.125  
0.120  
0.115  
0.110  
0.105  
0.100  
0.095  
0.090  
60  
40  
V = 5V  
S
20  
0
–20  
–40  
–60  
–6  
–4  
–2  
0
2
4
6
V
(V)  
OUT  
Figure 20. Input Error Voltage vs. Output Voltage  
Figure 23. Small Signal Transient Response for Various Supplies  
Rev. E | Page 9 of 20  
ADA4841-1/ADA4841-2  
6
4.5  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
0
G = +2  
= 5  
TIME = 100ns/DIV  
V
= 5V  
V
S
IN  
V
G = +1  
TIME = 200ns/DIV  
S
5
V
OUT  
+125°C  
4
3
+25°C  
–40°C  
2
1
0
–1  
Figure 24. Input Overdrive Recovery  
Figure 27. Slew Rate vs. Temperature  
6
5
2.0  
2.0  
1.5  
V
= 5V  
V
× 2  
V
= 5V  
S
IN  
S
G = +2  
TIME = 100ns/DIV  
G = +1  
V = 2V p-p  
OUT  
1.5  
TIME = 100ns/DIV  
V
OUT  
1.0  
1.0  
4
V
OUT  
0.5  
0.5  
V
(EXPANDED)  
OUT  
3
V
IN  
0
0
2
–0.5  
–1.0  
–1.5  
–2.0  
–0.5  
–1.0  
–1.5  
–2.0  
1
0
–1  
Figure 25. Output Overdrive Recovery  
Figure 28. Settling Time  
6
5
1.2  
1.0  
0.8  
0.6  
0.4  
0.2  
0
1.5  
1.0  
V
V
=
±
5V  
= 2V p-p  
S
+25°C  
POWER DOWN PIN  
OUT  
TIME = 100ns/DIV  
4
G = +2  
0.5  
–40°C  
+125°C  
3
G = +1  
0
2
–0.5  
–1.0  
–1.5  
1
V
= 5V  
S
0
G = +1  
V
= 1V  
IN  
DC  
TIME = 200ns/DIV  
–1  
–0.2  
Figure 29. Power-Up Time vs. Temperature  
Figure 26. Large Signal Transient Response for Various Gains  
Rev. E | Page 10 of 20  
ADA4841-1/ADA4841-2  
6
5
1.2  
1.0  
0.8  
0.6  
0.4  
0.2  
0
0
–20  
V
= 5V  
S
V = 5V  
S
G = +1  
V
TIME = 10μs/DIV  
POWER DOWN PIN  
= 1V  
IN  
DC  
4
–40  
+PSR  
3
+125°C  
+25°C  
–60  
2
–80  
–40°C  
1
–PSR  
–100  
–120  
0
POWER DOWN PIN  
–1  
–0.2  
100  
1k  
10k  
100k  
1M  
10M  
100M  
FREQUENCY (Hz)  
POWER DOWN  
Figure 30.  
Time vs. Temperature  
Figure 33. PSR vs. Frequency  
1.6  
1.4  
1.2  
1.0  
0.8  
0.6  
0.4  
0.2  
0
100  
10  
V
= 5V  
V
= 5V  
S
S
+125°C  
+25°C  
–40°C  
1
0.1  
0.01  
0.001  
–0.2  
0
0.5  
1.0  
1.5  
2.0  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
100  
1k  
10k  
100k  
1M  
10M  
100M  
FREQUENCY (Hz)  
POWER DOWN PIN (V)  
Figure 34. Output Impedance vs. Frequency  
POWER DOWN  
Figure 31. Supply Current per Amplifier vs.  
Pin Voltage  
40  
30  
0
V
= ±5V  
S
G = +1  
–20  
–40  
V
= +5V  
S
20  
10  
0
V
= ±5V  
–60  
–80  
S
–10  
–20  
–30  
–40  
–50  
V
= +3V  
S
–100  
–120  
100  
1k  
10k  
100k  
1M  
10M  
100M  
–40 –25 –10  
5
20  
35  
50  
65  
80  
95 110 125  
TEMPERATURE (°C)  
FREQUENCY (Hz)  
Figure 32. CMR vs. Frequency  
Figure 35. Input Offset Voltage vs. Temperature for Various Supplies  
Rev. E | Page 11 of 20  
ADA4841-1/ADA4841-2  
–40  
–50  
–60  
–70  
3.6  
G = +1  
V
= 5V  
S
R
= 1k  
L
3.5  
V
= +5V  
S
3.4  
3.3  
3.2  
3.1  
–80  
–90  
A TO B  
V
= +3V  
S
–100  
–110  
–120  
V
= ±5V  
S
B TO A  
10M  
–130  
–140  
–40 –25 –10  
5
20  
35  
50  
65  
80  
95 110 125  
10k  
100k  
1M  
100M  
1G  
TEMPERATURE (°C)  
FREQUENCY (Hz)  
Figure 36. Input Bias Current vs. Temperature for Various Supplies  
Figure 38. Crosstalk Output to Output  
1.6  
1.5  
1.4  
1.3  
1.2  
V
= ±5V  
S
1.1  
1.0  
0.9  
0.8  
V
= +5V  
20  
S
V
= +3V  
S
–40 –25 –10  
5
35  
50  
65  
80  
95 110 125  
TEMPERATURE (°C)  
Figure 37. Supply Current vs. Temperature for Various Supplies  
Rev. E | Page 12 of 20  
ADA4841-1/ADA4841-2  
THEORY OF OPERATION  
The total output voltage error is the sum of errors due to the  
amplifier offset voltage and input currents. The output error  
due to the offset voltage can be estimated as  
AMPLIFIER DESCRIPTION  
The ADA4841-1/ADA4841-2 are low power, low noise,  
precision voltage-feedback op amps for single or dual voltage  
supply operation. The ADA4841-1/ADA4841-2 are fabricated  
on ADI’s second generation XFCB process and feature trimmed  
supply current and offset voltage. The 2.1 nV/√Hz voltage noise  
(very low for a 1.1 mA supply current amplifier), 40 μV offset  
voltage, and sub 1 μV/°C offset drift is accomplished with an  
input stage made of an undegenerated PNP input pair driving a  
symmetrical folded cascode. A rail-to-rail output stage provides  
the maximum linear signal range possible on low voltage  
supplies and has the current drive capability needed for the  
relatively low resistance feedback networks required for low  
noise operation. CMRR, PSRR, and open-loop gain are all  
typically above 100 dB, preserving the precision performance in  
a variety of configurations. Gain bandwidth is kept high for this  
power level to preserve the outstanding linearity performance  
for frequencies up to 100 kHz. The ADA4841-1 has a power-  
down function to further reduce power consumption. All this  
results in a low noise, power efficient, precision amplifier that is  
well-suited for high resolution and precision applications.  
VOUT  
=
ERROR  
(4)  
VP VPNOM VOUT  
RF  
RG  
VCM  
CMRR  
V
+
+
+
× 1+  
OFFSET  
NOM  
PSRR  
A
where:  
VOFFSET  
is the offset voltage at the specified supply voltage.  
NOM  
This is measured with the input and output at midsupply.  
VCM is the common-mode voltage.  
VP is the power supply voltage.  
Vp  
is the specified power supply voltage.  
NOM  
CMRR is the common-mode rejection ratio.  
PSRR is the power supply rejection ratio.  
A is the dc open-loop gain.  
DC ERRORS  
The output error due to the input currents can be estimated as  
Figure 39 shows a typical connection diagram and the major dc  
error sources. The ideal transfer function (all error sources set  
to 0 and infinite dc gain) can be written as  
RF  
RG  
RF  
RG  
VOUT  
= (RF || RG )× 1+  
IBRS × 1+  
×IB+  
(5)  
ERROR  
RF  
RG  
RF  
RG  
VOUT = 1+  
×VIP  
×VIN  
(1)  
Note that setting RS equal to RF||RG compensates for the voltage  
error due to the input bias current.  
R
F
NOISE CONSIDERATIONS  
– V  
+
+
+ V  
IN  
OS  
R
R
G
Figure 40 illustrates the primary noise contributors for the  
typical gain configurations. The total rms output noise is  
the root-mean-square of all the contributions.  
+ V  
OUT  
I
B
– V  
IP  
S
vn _ R  
=
4kT × R  
R
F
F
F
I
+
B
ven  
R
vn _ R  
=
G
S
4kT × R  
G
G
Figure 39. Typical Connection Diagram and DC Error Sources  
+ vout_en –  
ien  
ien  
This reduces to the familiar forms for inverting and  
noninverting op amp gain expressions  
R
vn _ R  
=
4kT × R  
S
S
RF  
RG  
VOUT = 1+  
×VIP  
(2)  
(3)  
Figure 40. Noise Sources in Typical Connection  
(Noninverting gain, VIN = 0 V)  
RF  
VOUT  
=
×VIN  
RG  
(Inverting gain, VIP = 0 V)  
Rev. E | Page 13 of 20  
 
 
 
 
 
 
ADA4841-1/ADA4841-2  
The input stage positive limit is almost exactly a volt below the  
positive supply at room temperature. Input voltages above that  
start to show clipping behavior. The positive input voltage limit  
increases with temperature with a coefficient of about 2 mV/°C.  
The lower supply limit is nominally below the minus supply;  
therefore, in a standard gain configuration, the output stage  
limits the signal headroom on the negative supply side. Figure 42  
and Figure 43 show the nominal CMRR behavior at the limits of  
the input headroom for three temperatures—this is generated  
using the subtractor topology shown in Figure 44, which avoids  
the output stage limitation.  
The output noise spectral density can be calculated by  
vout _en =  
2
2
RF  
RG  
RF  
RG  
4kTRs + ien2RS + ven  
]
+
4kTRg + ien2 RF  
2
2
2
4kTRf + 1+  
[
(6)  
where:  
k is Boltzmann’s Constant.  
T is the absolute temperature, degrees Kelvin.  
300  
260  
220  
180  
ien  
is the amplifier input current noise spectral density, pA/√Hz.  
is the amplifier input voltage spectral density, nV/√Hz.  
ven  
140  
100  
+125°C  
+25°C  
RS is the source resistance as shown in Figure 40.  
60  
20  
RF and RG are the feedback network resistances, as shown in  
Figure 40.  
–40°C  
–20  
–60  
–100  
–140  
–180  
–220  
–260  
–300  
ven  
Source resistance noise, amplifier voltage noise ( ), and the  
ien  
voltage noise from the amplifier current noise ( × RS) are  
all subject to the noise gain term (1 + RF/RG). Note that with a  
2.1 nV/√Hz input voltage noise and 1.4 pA/√Hz input current,  
the noise contributions of the amplifier are relatively small for  
source resistances between approximately 200 Ω and 30 kΩ.  
Figure 41 shows the total RTI noise due to the amplifier vs. the  
source resistance. In addition, the value of the feedback resistors  
used impacts the noise. It is recommended to keep the value of  
feedback resistors between 250 Ω and 1 kΩ to keep the total  
noise low.  
3.00 3.20 3.40 3.60 3.80 4.00 4.20 4.40 4.60 4.80 5.00  
COMMON-MODE VOLTAGE (V)  
Figure 42. +CMV vs. Common-Mode Error vs. VOS  
0
–50  
–100  
–150  
–40°C  
–200  
1000  
–250  
+25°C  
–300  
–350  
–400  
100  
–450  
AMPLIFIER + RESISTOR NOISE  
+125°C  
–500  
–550  
–600  
–650  
–700  
–750  
–800  
10  
TOTAL AMPLIFIER NOISE  
1
–4.00  
–6.00 –5.80 –5.60 –5.40 –5.20 –5.00 –4.80 –4.60 –4.40 –4.20  
COMMON-MODE VOLTAGE (V)  
SOURCE RESISTANCE NOISE  
0.1  
Figure 43. −CMV vs. Common-Mode Error vs. VOS  
10  
100  
1k  
10k  
100k  
– V  
+
+ V  
CM  
SOURCE RESISTANCE (Ω)  
OUT  
Figure 41. RTI Noise vs. Source Resistance  
HEADROOM CONSIDERATIONS  
Figure 44. Common-Range Subtractor  
The ADA4841-1/ADA4841-2 are designed to provide maximum  
input and output signal ranges with 16-bit to 18-bit dc linearity.  
As the input or output headroom limits are reached, the signal  
linearity degrades.  
Rev. E | Page 14 of 20  
 
 
 
 
 
ADA4841-1/ADA4841-2  
60  
50  
40  
30  
20  
10  
0
Figure 45 shows the amplifier frequency response as a G = −1  
inverter with the input and output stage biased near the  
negative supply rail.  
G = +1  
6
V
= 5V  
S+  
V
= –150mV  
S–  
G = –1  
V
= 20mV p-p  
V
= –100mV  
IN  
S–  
V
= –200mV  
3
0
S–  
V
= –50mV  
S–  
V
= –20mV  
–3  
–6  
–9  
–12  
S–  
G = +2  
G = +5  
10  
100  
1000  
10000  
CAPACITANCE LOAD (pF)  
Figure 46. Series Resistance vs. Capacitance Load  
0.1  
1
10  
FREQUENCY (MHz)  
100  
INPUT PROTECTION  
The ADA4841-1/ADA4841-2 are fully protected from ESD  
events, withstanding human body model ESD events of 2.5 keV  
and charge device model events of 1 keV with no measured  
performance degradation. The precision input is protected  
with an ESD network between the power supplies and diode  
clamps across the input device pair, as shown in Figure 47.  
Figure 45. Small Signal Frequency Response vs. Negative Supply Bias  
The input voltage (VIN) and reference voltage (VIP) are both at  
0 V, (see Figure 39). +VS is biased at +5 V, and −VS is swept  
from −200 mV to −20 mV. With the input and output voltages  
biased 200 mV above the bottom rail, the G = −1 inverter  
frequency response is not much different from what is seen  
with the input and output voltages biased near midsupply.  
At 150 mV bias, the frequency response starts to decrease  
and at 20 mV, the inverter bandwidth is less than half its  
nominal value.  
VCC  
BIAS  
ESD  
VP  
ESD  
ESD  
ESD  
VN  
CAPACITANCE DRIVE  
Capacitance at the output of an amplifier creates a delay within  
the feedback path that, if within the bandwidth of the loop, can  
create excessive ringing and oscillation. The G = +1 follower  
topology has the highest loop bandwidth of any typical  
configuration and, therefore, is the most vulnerable to the  
effects of capacitance load.  
VEE  
TO REST OF AMPLIFIER  
Figure 47. Input Stage and Protection Diodes  
For differential voltages above approximately 1.4 V, the diode  
clamps start to conduct. Too much current can cause damage  
due to excessive heating. If large differential voltages need to be  
sustained across the input terminals, it is recommended that the  
current through the input clamps be limited to below 150 mA.  
Series input resistors sized appropriately for the expected  
differential overvoltage provide the needed protection.  
A small resistor in series with the amplifier output and the  
capacitive load mitigates the problem. Figure 46 plots the  
recommended series resistance vs. capacitance for gains  
of +1, +2, and +5.  
The ESD clamps start to conduct for input voltages more than  
0.7 V above the positive supply and input voltages more than  
0.7 V below the negative supply. It is recommended that the  
fault current be limited to less than 150 mA if an overvoltage  
condition is expected.  
Rev. E | Page 15 of 20  
 
 
 
 
 
ADA4841-1/ADA4841-2  
POWER DOWN  
The  
pin is protected with ESD clamps,  
POWER-DOWN OPERATION  
as shown in Figure 48. Voltages beyond the power supplies  
cause these diodes to conduct. The guidelines for limiting the  
overload current in the input protection section should also be  
Figure 48 shows the ADA4841-1 power-down circuitry. If the  
POWER DOWN  
pin is left unconnected, then the base of the  
input PNP transistor is pulled high through the internal pull-up  
resistor to the positive supply, and the part is turned on. Pulling  
POWER DOWN  
followed for the  
pin.  
POWER DOWN  
the  
pin approximately 1.7 V below the positive  
supply turns the part off, reducing the supply current to  
approximately 40 μA.  
VCC  
I
BIAS  
ESD  
ESD  
POWER DOWN  
TO  
AMPLIFIER  
BIAS  
VEE  
POWER DOWN  
Figure 48.  
Circuit  
Rev. E | Page 16 of 20  
 
 
ADA4841-1/ADA4841-2  
APPLICATIONS INFORMATION  
TYPICAL PERFORMANCE VALUES  
RECONSTRUCTION FILTER  
To reduce design time and eliminate uncertainty Table 6  
provides a convenient reference for typical gains, component  
values, and performance parameters.  
The ADA4841-1/ADA4841-2 can also be used as a reconstruction  
filter at the output of DACs for suppression of the sampling  
frequency. The filter shown in Figure 49 is a two-pole, 500 kHz  
Sallen-Key LPF with a fixed gain of G = +1.6.  
16-BIT ADC DRIVER  
C2  
1320pF  
The combination of low noise, low power, and high speed  
make the ADA4841-1/ADA4841-2 the perfect driver solution  
for low power, 16-bit ADCs, such as the AD7685. Figure 50  
shows a typical 16-bit single-supply application.  
10μF  
+5V  
0.1μF  
R1  
249Ω  
R2  
249Ω  
There are different challenges to a single-supply, high resolution  
design, and the ADA4841-1/ADA4841-2 address these nicely.  
In a single-supply system, a main challenge is using the  
amplifier in buffer mode with the lowest output noise and  
preserving linearity compatible with the ADC.  
INPUT  
C1  
1320pF  
OUTPUT  
U1  
0.1μF  
10μF  
–5V  
Rail-to-rail input amplifiers are usually higher noise than the  
ADA4841-1/ADA4841-2 and cannot be used in this mode  
because of the nonlinear region around the crossover point of  
their input stages. The ADA4841-1/ADA4841-2, which have no  
crossover region but have a wide linear input range from 100 mV  
below ground to 1 V below positive rail, solve this problem, as  
shown in Figure 50. The amplifier, when configured as a  
follower, has a linear signal range from 0.25 V above the minus  
supply voltage (limited by the amplifiers output stage) to 1 V  
below the positive supply (limited by the amplifier input stage).  
A 0 V to +4.096 V signal range can be accommodated with a  
positive supply as low as +5.2 V and a negative power supply of  
−0.25 V. The 5.2 V supply also allows the use of a small, low  
dropout, low temperature drift ADR364 reference voltage. If  
ground is used as the amplifier negative supply, then note that at  
the low end of the input range close to ground, the ADA4841-1/  
ADA4841-2 exhibit substantial nonlinearity, as any rail-to-rail  
output amplifier. The ADA4841-1/ADA4841-2 drive a one-  
pole, low-pass filter. This filter limits the already very low noise  
contribution from the amplifier to the AD7685.  
R3  
840Ω  
R4  
499Ω  
Figure 49. Two-Pole 500 kHz Reconstruction Filter Schematic  
Setting the resistors and capacitors equal to each other greatly  
simplifies the design equations for the Sallen-Key filter. The corner  
frequency, or −3 dB frequency, can be described by the equation  
1
fC  
=
2πR1C1  
The quality factor, or Q, is shown in the equation  
1
Q =  
3 K  
For minimum peaking, set Q equal to 0.707.  
The gain, or K, of the amplifier is  
R4  
R3  
K =  
+1  
Resistor values are kept low for minimal noise contribution,  
offset voltage, and optimal frequency response.  
+5.2V  
100nF  
ADR364  
100nF  
10μF  
100nF  
ADA4841  
REF  
VDD VIO  
0V TO 4.096V  
33Ω  
SDI  
SCK  
SDO  
CNV  
IN+  
2.7nF  
AD7685  
–0.25V  
IN–  
GND  
Figure 50. ADC Driver Schematic  
Rev. E | Page 17 of 20  
 
 
 
 
 
ADA4841-1/ADA4841-2  
Table 6. Recommended Values and Typical Performance  
Peaking Output Noise ADA4841-1/ Total Output Noise  
Gain RF (Ω) RG (Ω) −3 dB BW (MHz) Slew Rate (V/μs) (dB) ADA4841-2 Only (nV/√Hz) Including Resistors (nV/√Hz)  
+1  
+2  
−1  
+5  
+10  
+20  
0
N/A  
499  
499  
124  
54.9  
26.1  
77  
34  
38  
11  
5
12.5  
12.5  
12.5  
12  
12  
11.2  
0.9  
0.3  
0.4  
0
0
0
2
4
4
10  
20  
40  
2
499  
499  
499  
499  
499  
5.73  
5.73  
11.9  
21.1  
42.2  
2.3  
POWER SUPPLY BYPASSING  
Capacitor selection is critical for optimal filter performance.  
Capacitors with low temperature coefficients, such as NPO  
ceramic capacitors, are good choices for filter elements. Figure 51  
shows the filter response.  
Power supply bypassing is a critical aspect in the performance  
of the ADA4841-1/ADA4841-2. A parallel connection of  
capacitors from each of the power supply pins to ground works  
best. A typical connection is shown in Figure 49. Smaller value  
capacitors offer better high frequency response where larger  
value electrolytics offer better low frequency performance.  
Paralleling different values and sizes of capacitors helps to  
ensure that the power supply pins are provided a low ac impedance  
across a wide band of frequencies. This is important for minimizing  
the coupling of noise into the amplifier. This can be especially  
important when the amplifier PSR is starting to roll off—the  
bypass capacitors can help lessen the degradation in PSR  
performance.  
5
0
–5  
–10  
–15  
–20  
–25  
–30  
–35  
–40  
Starting directly at the ADA4841-1/ADA4841-2 power supply  
pins, the smallest value capacitor should be placed on the same  
side of the board as the amplifier, and as close as possible to the  
amplifier power supply pin. The ground end of the capacitor  
should be connected directly to the ground plane. Keeping the  
capacitors’ distance short but equal from the load is important  
and can improve distortion performance. This process should  
be repeated for the next largest value capacitor.  
0.03  
0.1  
1
10  
FREQUENCY (MHz)  
Figure 51. Filter Frequency Response  
LAYOUT CONSIDERATIONS  
To ensure optimal performance, careful and deliberate attention  
must be paid to the board layout, signal routing, power supply  
bypassing, and grounding.  
It is recommended that a 0.1 μF ceramic 0508 case be used. The  
0508 case size offers low series inductance and excellent high  
frequency performance. A 10 μF electrolytic capacitor should be  
placed in parallel with the 0.1 μF capacitor. Depending on the  
circuit parameters, some enhancement to performance can be  
realized by adding additional capacitors. Each circuit is different  
and should be individually analyzed for optimal performance.  
GROUND PLANE  
It is important to avoid ground in the areas under and around  
the input and output of the ADA4841-1/ADA4841-2. Stray  
capacitance created between the ground plane and the input  
and output pads of a device are detrimental to high speed  
amplifier performance. Stray capacitance at the inverting input,  
along with the amplifier input capacitance, lowers the phase  
margin and can cause instability. Stray capacitance at the output  
creates a pole in the feedback loop. This can reduce phase  
margin and can cause the circuit to become unstable.  
Rev. E | Page 18 of 20  
 
 
 
 
 
ADA4841-1/ADA4841-2  
OUTLINE DIMENSIONS  
5.00 (0.1968)  
4.80 (0.1890)  
3.20  
3.00  
2.80  
8
1
5
4
6.20 (0.2441)  
5.80 (0.2284)  
4.00 (0.1574)  
3.80 (0.1497)  
8
1
5
4
5.15  
4.90  
4.65  
3.20  
3.00  
2.80  
0.50 (0.0196)  
0.25 (0.0099)  
1.27 (0.0500)  
BSC  
45°  
1.75 (0.0688)  
1.35 (0.0532)  
PIN 1  
IDENTIFIER  
0.25 (0.0098)  
0.10 (0.0040)  
8°  
0°  
0.65 BSC  
0.51 (0.0201)  
0.31 (0.0122)  
COPLANARITY  
0.10  
1.27 (0.0500)  
0.40 (0.0157)  
0.25 (0.0098)  
0.17 (0.0067)  
0.95  
0.85  
0.75  
SEATING  
PLANE  
15° MAX  
1.10 MAX  
COMPLIANT TO JEDEC STANDARDS MS-012-AA  
0.80  
0.55  
0.40  
0.15  
0.05  
0.23  
0.09  
6°  
0°  
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS  
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR  
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.  
0.40  
0.25  
COPLANARITY  
0.10  
COMPLIANT TO JEDEC STANDARDS MO-187-AA  
Figure 53. 8-Lead Mini Small Outline Package [MSOP]  
(RM-8)  
Figure 52. 8-Lead Standard Small Outline Package [SOIC_N]  
Narrow Body (R-8)  
Dimensions shown in millimeters  
Dimensions shown in millimeters and (inches)  
3.00  
2.90  
2.80  
6
1
5
2
4
3
3.00  
2.80  
2.60  
1.70  
1.60  
1.50  
PIN 1  
INDICATOR  
0.95 BSC  
1.90  
BSC  
1.30  
1.15  
0.90  
0.20 MAX  
0.08 MIN  
1.45 MAX  
0.95 MIN  
0.55  
0.45  
0.15 MAX  
0.05 MIN  
10°  
4°  
0°  
SEATING  
PLANE  
0.60  
0.50 MAX  
0.30 MIN  
0.35  
BSC  
COMPLIANT TO JEDEC STANDARDS MO-178-AB  
Figure 54. 6-Lead Small Outline Transistor Package [SOT-23]  
(RJ-6)  
Dimensions shown in millimeters  
Rev. E | Page 19 of 20  
 
ADA4841-1/ADA4841-2  
2.54  
2.44  
2.34  
3.10  
3.00 SQ  
2.90  
0.50 BSC  
8
5
PIN 1 INDEX  
AREA  
EXPOSED  
PAD  
1.80  
1.70  
1.60  
0.50  
0.40  
0.30  
4
1
PIN 1  
INDICATOR  
(R 0.15)  
TOP VIEW  
BOTTOM VIEW  
FOR PROPER CONNECTION OF  
THE EXPOSED PAD, REFER TO  
THE PIN CONFIGURATION  
OF THIS DATA SHEET.  
0.80  
0.75  
0.70  
0.05 MAX  
0.02 NOM  
COPLANARITY  
0.08  
SEATING  
PLANE  
0.30  
0.25  
0.20  
0.203 REF  
COMPLIANT TO JEDEC STANDARDS MO-229-WEED  
Figure 55. 8-Lead Lead Frame Chip Scale Package [LFCSP_WD]  
3 mm × 3 mm Body, Very Very Thin, Dual Lead  
(CP-8-11)  
Dimensions shown in millimeters  
ORDERING GUIDE  
Model1  
Temperature Range  
Package Description  
8-Lead SOIC_N  
8-Lead SOIC_N  
8-Lead SOIC_N  
6-Lead SOT-23  
Package Option  
R-8  
R-8  
R-8  
RJ-6  
Ordering Quantity  
Branding  
ADA4841-1YRZ  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
1
ADA4841-1YRZ-R7  
ADA4841-1YRZ-RL  
ADA4841-1YRJZ-R2  
ADA4841-1YRJZ-R7  
ADA4841-1YRJZ-RL  
ADA4841-2YRMZ  
ADA4841-2YRMZ-R7  
ADA4841-2YRMZ-RL  
ADA4841-2YRZ  
ADA4841-2YRZ-R7  
ADA4841-2YRZ-RL  
ADA4841-2YCPZ-R2  
ADA4841-2YCPZ-R7  
ADA4841-2YCPZ-RL  
ADA4841-1YR-EBZ  
ADA4841-1YRJ-EBZ  
ADA4841-2YRM-EBZ  
ADA4841-2YR-EBZ  
1,000  
2,500  
250  
3,000  
10,000  
1
1,000  
3,000  
1
1,000  
2,500  
250  
HQB  
HQB  
HQB  
HRB  
HRB  
HRB  
6-Lead SOT-23  
6-Lead SOT-23  
RJ-6  
RJ-6  
8-Lead MSOP  
8-Lead MSOP  
8-Lead MSOP  
RM-8  
RM-8  
RM-8  
R-8  
R-8  
R-8  
CP-8-11  
CP-8-11  
CP-8-11  
8-Lead SOIC_N  
8-Lead SOIC_N  
8-Lead SOIC_N  
8-Lead LFCSP_WD  
8-Lead LFCSP_WD  
8-Lead LFCSP_WD  
Evaluation Board  
Evaluation Board  
Evaluation Board  
Evaluation Board  
HRB  
HRB  
HRB  
1,500  
5,000  
1 Z = RoHS Compliant Part.  
©2005–2010 Analog Devices, Inc. All rights reserved. Trademarks and  
registered trademarks are the property of their respective owners.  
D05614–0–12/10(E)  
Rev. E | Page 20 of 20  
 

相关型号:

ADA4841-2YR-EBZ

Low Power, Low Noise and Distortion ail-to-Rail Output Amplifiers
ADI

ADA4841-2YRM-EBZ

Low Power, Low Noise and Distortion ail-to-Rail Output Amplifiers
ADI

ADA4841-2YRMZ

Low Power, Low Noise and Distortion, Rail-to-Rail Output Amplifier
ADI

ADA4841-2YRMZ

DUAL OP-AMP, 300 uV OFFSET-MAX, PDSO8, ROHS COMPLIANT, MO-187AA, MSOP-8
ROCHESTER

ADA4841-2YRMZ-R7

Low Power, Low Noise and Distortion, Rail-to-Rail Output Amplifier
ADI

ADA4841-2YRMZ-RL

Low Power, Low Noise and Distortion, Rail-to-Rail Output Amplifier
ADI

ADA4841-2YRZ

Low Power, Low Noise and Distortion, Rail-to-Rail Output Amplifier
ADI

ADA4841-2YRZ

DUAL OP-AMP, 300 uV OFFSET-MAX, PDSO8, ROHS COMPLIANT, MS-012AA, SOIC-8
ROCHESTER

ADA4841-2YRZ-R7

Low Power, Low Noise and Distortion, Rail-to-Rail Output Amplifier
ADI

ADA4841-2YRZ-RL

Low Power, Low Noise and Distortion, Rail-to-Rail Output Amplifier
ADI

ADA4841-2YRZ-RL

DUAL OP-AMP, 300 uV OFFSET-MAX, PDSO8, ROHS COMPLIANT, MS-012AA, SOIC-8
ROCHESTER

ADA4841-2_15

Low Power, Low Noise and Distortion, Rail-to-Rail Output Amplifiers
ADI