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Low Cost, 300 MHz Voltage Feedback Amplifiers AD8055/AD8056
FEATURES
Low cost single (AD8055) and dual (AD8056) Easy-to-use voltage feedback architecture High speed 300 MHz, -3 dB bandwidth (G = +1) 1400 V/s slew rate 20 ns settling to 0.1% Low distortion: -72 dBc @ 10 MHz Low noise: 6 nV/Hz Low dc errors: 5 mV max VOS, 1.2 A max IB Small packaging AD8055 available in 5-lead SOT-23 AD8056 available in 8-lead MSOP Excellent video specifications (RL = 150 , G = +2) Gain flatness 0.1 dB to 40 MHz 0.01% differential gain error 0.02 differential phase error Drives 4 video loads (37.5 V) with 0.02% differential Gain and 0.1 differential phase Low power, 5 V supplies 5 mA typ/amplifier power supply current High output drive current: over 60 mA
NC -IN +IN -VS
1 2 3 4
CONNECTION DIAGRAMS
8 7 6
NC +VS VOUT
01063-001
VOUT -VS +IN
1 2 3
5
+VS
AD8055
NC = NO CONNECT
5
NC
4
-IN
AD8055
Figure 1. N-8 and R-8
OUT1 -IN1 +IN1 -VS
1 2 3 4 8 7 6
Figure 2. RJ-5
+VS OUT -IN2 +IN2
01063-003
AD8056
5
Figure 3. N-8, R-8, and RM-8
Their 0.1 dB flatness out to 40 MHz, wide bandwidth out to 300 MHz, along with 1400 V/s slew rate and 20 ns settling time, make them useful for a variety of high speed applications. The AD8055 and AD8056 require only 5 mA typ/amplifier of supply current and operate on a dual 5 V or a single +12 V power supply, while capable of delivering over 60 mA of load current. The AD8055 is available in a small 8-lead PDIP, an 8-lead SOIC, and a 5-lead SOT-23, while the AD8056 is available in an 8-lead MSOP. These features make the AD8055/AD8056 ideal for portable and battery-powered applications where size and power are critical. These amplifiers in the R-8, N-8, and RM-8 packages are available in the extended temperature range of -40C to +125C.
5 4 3 2 VIN 50 RG RF RL G = +1 RF = 0 RC = 100 RC VOUT VOUT = 100mV p-p RL = 100
APPLICATIONS
Imaging Photodiode preamps Video line drivers Differential line drivers Professional cameras Video switchers Special effects A-to-D drivers Active filters
GENERAL DESCRIPTION
The AD8055 (single) and AD8056 (dual) voltage feedback amplifiers offer bandwidth and slew rate typically found in current feedback amplifiers. Additionally, these amplifiers are easy to use and available at a very low cost. Despite their low cost, the AD8055 and AD8056 provide excellent overall performance. For video applications, their differential gain and phase error are 0.01% and 0.02 into a 150 load and 0.02% and 0.1 while driving four video loads (37.50 ).
Rev. J
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 registered trademarks are the property of their respective owners.
GAIN (dB)
1 0 -1 -2 -3 -4 -5 0.3M 1M G = +10 RF = 909 G = +5 RF = 1000 10M 100M FREQUENCY (Hz)
G = +2 RF = 402
1G
Figure 4. Frequency Response
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 (c)2006 Analog Devices, Inc. All rights reserved.
01063-004
01063-002
AD8055/AD8056 TABLE OF CONTENTS
Features .............................................................................................. 1 Applications....................................................................................... 1 General Description ......................................................................... 1 Connection Diagrams...................................................................... 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Absolute Maximum Ratings............................................................ 5 Maximum Power Dissipation ..................................................... 5 ESD Caution.................................................................................. 5 Typical Performance Characteristics ............................................. 6 Test Circuits..................................................................................... 11 Applications..................................................................................... 12 Four-Line Video Driver............................................................. 12 Single-Ended-to-Differential Line Driver............................... 12 Low Noise, Low Power Preamp................................................ 12 Power Dissipation Limits .......................................................... 13 Resistor Selection ....................................................................... 13 Driving Capacitive Loads.......................................................... 13 Outline Dimensions ....................................................................... 14 Ordering Guide .......................................................................... 16
REVISION HISTORY
2/06--Rev. I to Rev. J Changes to Format .............................................................Universal Updated Outline Dimensions ....................................................... 15 Changes to Ordering Guide .......................................................... 16 2/04--Rev. H to Rev. I Changes to Features.......................................................................... 1 Changes to Ordering Guide ............................................................ 3 6/03--Rev. G to Rev. H Changes to Absolute Maximum Ratings ....................................... 3 Updated Ordering Guide................................................................. 3 Updated Outline Dimensions ....................................................... 11 2/03--Rev. F to Rev. G Changes to Product Description .................................................... 1 Changes to Specifications ................................................................ 2 Change to Ordering Guide.............................................................. 3 Outline Dimensions Updated ....................................................... 11 10/02--Rev. E to Rev. F Text Changes to Reflect Extended Temperature Range for R-8, N-8 Packages..............................................................................1 Changes to Specifications.................................................................2 Changes to Absolute Maximum Ratings........................................3 Figure 2 Replaced ..............................................................................3 Changes to Ordering Guide .............................................................3 Outline Dimensions Updated....................................................... 11 7/01--Rev. D to Rev. E TPC 24 Replaced with New Graph .................................................7 3/01--Rev. C to Rev. D Edit to Curve in TPC 23 ...................................................................7 2/01--Rev. B to Rev. C Edits to Text at Top of Specifications Page (65 to 5)....................2
Rev. J | Page 2 of 16
AD8055/AD8056 SPECIFICATIONS
TA = 25C, VS = 5 V, RF = 402 , RL = 100 , Gain = +2, unless otherwise noted. Table 1.
Parameter DYNAMIC PERFORMANCE -3 dB Bandwidth Conditions G = +1, VO = 0.1 V p-p G=+1, VO = 2 V p-p G=+2, VO = 0.1 V p-p G=+2, VO = 2 V p-p VO = 100 mV p-p G = +1, VO = 4 V step G = +2, VO = 4 V step G = +2, VO = 2 V step G = +1, VO = 0.5 V step G = +1, VO = 4 V step G = +2, VO = 0.5 V step G = +2, VO = 4 V step fC = 10 MHz, VO = 2 V p-p, RL = 1 k fC = 20 MHz, VO = 2 V p-p, RL = 1 k f = 5 MHz, G = +2 f = 100 kHz f = 100 kHz NTSC, G = +2, RL = 150 NTSC, G = +2, RL = 37.5 NTSC, G = +2, RL = 150 NTSC, G = +2, RL = 37.5 AD8055A/AD8056A Min Typ Max 220 125 120 125 25 1000 750 300 150 160 150 40 1400 840 20 2 2.7 2.8 4 -72 -57 -60 6 1 0.01 0.02 0.02 0.1 3 TMIN to TMAX Offset Drift Input Bias Current Open-Loop Gain INPUT CHARACTERISTICS Input Resistance Input Capacitance Input Common-Mode Voltage Range Common-Mode Rejection Ratio OUTPUT CHARACTERISTICS Output Voltage Swing Output Current 1 Short-Circuit Current1 TMIN to TMAX VO = 2.5 V TMIN to TMAX 6 0.4 1 66 64 71 1.2 5 10 Unit MHz MHz MHz MHz MHz V/s V/s ns ns ns ns ns dBc dBc dB nV/Hz pA/Hz % % Degree Degree mV mV V/C A A dB dB M pF V dB V mA mA
Bandwidth for 0.1 dB Flatness Slew Rate Settling Time to 0.1% Rise and Fall Time, 10% to 90%
NOISE/HARMONIC PERFORMANCE Total Harmonic Distortion Crosstalk, Output-to-Output (AD8056) Input Voltage Noise Input Current Noise Differential Gain Error Differential Phase Error DC PERFORMANCE Input Offset Voltage
VCM = 2.5 V RL = 150 VO = 2.0 V 2.9 55
10 2 3.2 82 3.1 60 110
Rev. J | Page 3 of 16
AD8055/AD8056
Parameter POWER SUPPLY Operating Range Quiescent Current Conditions AD8055A/AD8056A Min Typ Max 4.0 AD8055 TMIN to 125C TMIN to 85C AD8056 TMIN to 125C TMIN to 85C +VS = +5 V to +6 V, -VS = -5 V -VS = -5 V to -6 V, +VS = +5 V AD8055ART AD8055AR, AD8055AN, AD8056AR, AD8056AN, AD8056ARM 5.0 5.4 7.6 10 13.9 66 69 -40 -40 72 86 +85 +125 6.0 6.5 7.3 12 13.3 Unit V mA mA mA mA mA mA dB dB C C
Power Supply Rejection Ratio OPERATING TEMPERATURE RANGE
1
Output current is limited by the maximum power dissipation in the package. See Figure 5.
Rev. J | Page 4 of 16
AD8055/AD8056 ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter Supply Voltage Input Voltage (Common Mode) Differential Input Voltage Output Short-Circuit Duration Storage Temperature Range N, R Operating Temperature Range (A Grade) Lead Temperature (Soldering 10 sec) Ratings 13.2 V VS 2.5 V Observe Power Derating Curves -65C to +150C -40C to +125C 300C
MAXIMUM POWER DISSIPATION
The maximum power that can be safely dissipated by the AD8055/AD8056 is limited by the associated rise in junction temperature. The maximum safe junction temperature for plastic encapsulated devices is determined by the glass transition temperature of the plastic, approximately 150C. Exceeding this limit temporarily can cause a shift in parametric performance due to a change in the stresses exerted on the die by the package. Exceeding a junction temperature of 175C for an extended period can result in device failure. While the AD8055/AD8056 are internally short-circuit protected, this may not be sufficient to guarantee that the maximum junction temperature (150C) is not exceeded under all conditions. To ensure proper operation, it is necessary to observe the maximum power derating curves.
2.5
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.
MAXIMUM POWER DISSIPATION (W)
2.0 SOIC-8 1.5 PDIP-8
1.0 MSOP-8 0.5 SOT-23-5
-55 -45 -35 -25 -15 -5
5
15 25 35 45 55 65 75 85 95 105 115 125
AMBIENT TEMPERATURE (C)
Figure 5. Plot of Maximum Power Dissipation vs. Temperature for AD8055/AD8056
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.
Rev. J | Page 5 of 16
01063-005
0
AD8055/AD8056 TYPICAL PERFORMANCE CHARACTERISTICS
0V
0V
01063-007
20mV
5ns
1V
5ns
Figure 6. Small Step Response, G = +1 (See Figure 34)
5 4 3 2
Figure 9. Large Step Response, G = -1 (See Figure 35)
VIN 50
RC
VOUT
VOUT = 100mV p-p RL = 100 G = +1 RF = 0 RC = 100
RG
RF
RL
0V
GAIN (dB)
1 0 -1 -2 -3 G = +10 RF = 909 G = +5 RF = 1000 1M 10M 100M FREQUENCY (Hz)
G = +2 RF = 402
01063-008
1V
5ns
-4 -5 0.3M
01063-011
1G
Figure 7. Large Step Response, G = +1 (See Figure 34)
Figure 10. Small Signal Frequency Response, G = +1, G = +2, G = +5, G = +10
5 4 3 2
VOUT = 2V p-p RL = 100
0V
GAIN (dB)
1 0 -1 -2 -3 G = +10 RF = 909 G = +5 RF = 1000 1M 10M 100M FREQUENCY (Hz) G = +2 RF = 402
G = +1 RF = 0
20mV
5ns
01063-010
-4 -5 0.3M
1G
Figure 8. Small Step Response, G = -1 (See Figure 35)
Figure 11. Large Signal Frequency Response, G = +1, G = +2, G = +5, G = +10
Rev. J | Page 6 of 16
01063-013
01063-012
AD8055/AD8056
0.5 0.4 0.3 0.2
OUTPUT (dB)
-40
VOUT = 100mV G = +2 RL = 100 RF = 402
DISTORTION (dBc)
-50
G = +2 RL = 1k
0.1 0 -0.1 -0.2 -0.3 -0.4
01063-014
-60 SECOND -70 THIRD
-80
1M
10M 100M FREQUENCY (Hz)
1G
0
0.4
0.8
1.2
1.6 2.0 2.4 VOUT (V p-p)
2.8
3.2
3.6
4.0
Figure 12. 0.1 dB Flatness
-50 VOUT = 2V p-p G = +2 RL = 100
10 9
Figure 15. Distortion vs. VOUT @ 20 MHz
RISE TIME AND FALL TIME (ns)
HARMONIC DISTORTION (dBc)
-60
G = +1 RL = 100 RF = 0
8 7 6 5 4 3 2 1 RISE TIME 0 0.5 1.0 1.5 2.0 2.5 3.0 VIN (V p-p) 3.5 4.0 4.5 5.0
01063-018
01063-019
-70
SECOND
-80 THIRD -90
FALL TIME
01063-015
-100 10k
100k
1M FREQUENCY (Hz)
10M
100M
0
Figure 13. Harmonic Distortion vs. Frequency
10
Figure 16. Rise Time and Fall Time vs. VIN
-50
RISE TIME AND FALL TIME (ns)
HARMONIC DISTORTION (dBc)
-60
VOUT = 2V p-p G = +2 RL = 1k
9 8 7 6 5 4 3 2 1 0 0
G = +1 RL = 1k RF = 0
-70
-80 SECOND -90 THIRD
01063-016
FALL TIME
RISE TIME
-100 10k
0.5
1.0
1.5
100k
1M FREQUENCY (Hz)
10M
100M
2.0 2.5 3.0 VIN (V p-p)
3.5
4.0
4.5
5.0
Figure 17. Rise Time and Fall Time vs. VIN
Figure 14. Harmonic Distortion vs. Frequency
Rev. J | Page 7 of 16
01063-017
-0.5 0.3M
-90
AD8055/AD8056
0.7 0.6 0.5 0.4 0.3
ERROR (%) -20
PSRR (dB)
10
VOUT = 0V TO +2V OR VOUT = 0V TO -2V G = +2 RL = 100
0 -10
G = +2 RF = 402
0.2 0.1 0 -0.1 -0.2 -0.3 -0.4
01063-020
-30 -40 -50 -60 -70 -80
-PSRR
+PSRR
0
10
20
30 TIME (ns)
40
50
60
1
10 FREQUENCY (MHz)
100
500
Figure 18. Settling Time
10 9 G = +2 RL = 100 RF = 402
Figure 21. PSRR vs. Frequency
RISE TIME AND FALL TIME (ns)
8 7 6 5 4 3 2 1 0 0 0.2 0.4 FALL TIME 0.6 0.8 1.0 VIN (V p-p) 1.2 1.4 1.6
01063-021
G = +1 RL = 100 VS = 5V
VIN VOUT
RISE TIME
1V
50ns
Figure 19. Rise Time and Fall Time vs. VIN
5.0 4.5 G = +2 RL = 1k RF = 402
Figure 22. Overload Recovery
-20 -30 -40
CROSSTALK (dB)
RISE TIME AND FALL TIME (ns)
4.0 3.5
VIN = 0dBm G = +2 RL = 100 RF = 402
RISE TIME 3.0 2.5 2.0 1.5 1.0 0.5 0 0.2 0.4 0.6 0.8 1.0 VIN (V p-p) 1.2 1.4 1.6
01063-022
-50 -60 -70 -80 -90 SIDE 1 DRIVEN SIDE 2 DRIVEN
FALL TIME
-100 -110 1 10 FREQUENCY (MHz) 100 200
01063-025
0
-120 0.1
Figure 20. Rise Time and Fall Time vs. VIN Figure 23. Crosstalk (Output-to-Output) vs. Frequency
Rev. J | Page 8 of 16
01063-024
01063-023
-0.5
-90 0.1
AD8055/AD8056
0 -10 -20 -30
CMRR (dB)
402 402 58
402
180
50
135
PHASE (Degrees)
402
-40 -50 -60 -70 -80 -90
01063-026
90 45 0 -45 -90 10k
1
10 FREQUENCY (MHz)
100
500
100k
1M 10M FREQUENCY (Hz)
100M
500M
Figure 24. CMRR vs. Frequency
DIFFERENTIAL GAIN (%) 0.04 0.02 0 -0.02 -0.04 0.04 0.02 0 -0.02 -0.04
Figure 27. Phase vs. Frequency
G = +2 RL = 100 RF = 402 VS = 5V
VIN (1V/DIV) VOUT (2V/DIV)
1 BACK TERMINATED LOAD (150)
G = +2 RF = 402 1ST 2ND 3RD 4TH 5TH 6TH 7TH 8TH 9TH 10TH 11TH IRE 1 BACK TERMINATED LOAD (150)
DIFFERENTIAL PHASE (Degrees)
01063-027
50ns
G = +2 RF = 402 1ST 2ND 3RD 4TH 5TH 6TH 7TH 8TH 9TH 10TH 11TH IRE
01063-030 01063-031
Figure 25. Overload Recovery
90 80 70
OPEN-LOOP GAIN (dB)
Figure 28. Differential Gain and Differential Phase
DIFFERENTIAL GAIN (%) 0.04 0.02 0 -0.02 -0.04 0.15 0.10 0.05 0 -0.05 -0.10 -0.15 G = +2 RF = 402 1ST 2ND 3RD 4TH 5TH 6TH 7TH 8TH 9TH 10TH 11TH IRE G = +2 RF = 402 1ST 2ND 3RD 4TH 5TH 6TH 7TH 8TH 9TH 10TH 11TH IRE 4 VIDEO LOADS (37.5)
4 VIDEO LOADS (37.5)
RL = 100
60 50 40 30 20 10 0 0.1 1 10 FREQUENCY (MHz) 100 500
01063-028
-10 0.01
DIFFERENTIAL PHASE (Degrees)
Figure 26. Open-Loop Gain vs. Frequency
Figure 29. Differential Gain and Differential Phase
Rev. J | Page 9 of 16
01063-029
-100 0.1
AD8055/AD8056
5.0 4.5 RL = 1k VS = 5V 100
3.5
CURRENT NOISE (pA/ Hz)
4.0
10
VOUT (V)
3.0 2.5 2.0 1.5 1.0 0.5
01063-032
RL = 150
RL = 50
1
-35
-15
5 25 45 65 TEMPERATURE (C)
85
105
125
100
1k
10k 100k FREQUENCY (Hz)
1M
10M
50M
Figure 30. Output Swing vs. Temperature
1000 45 40
Figure 32. Current Noise vs. Frequency
G = +2 RF = 402
VOLTAGE NOISE (nV/ Hz)
35 100 |ZOUT| () 30 25 20 15 10 5 0
01063-033
10
6nV/ Hz
100
1k
10k 100k FREQUENCY (Hz)
1M
10M
50M
0.1
1 10 FREQUENCY (MHz)
100
500
Figure 31. Voltage Noise vs. Frequency
Figure 33. Output Impedance vs. Frequency
Rev. J | Page 10 of 16
01063-035
1 10
-5 0.01
01063-034
0 -55
0.1 10
AD8055/AD8056 TEST CIRCUITS
+VS 4.7F 0.01F 0.001F HP8130A PULSE GENERATOR TR/TF = 1ns VIN 100
3 7
402 +VS 4.7F 0.01F
50
2
AD8055
4
VOUT
6
0.001F HP8130A PULSE GENERATOR TR/TF = 0.67ns VIN 402 57
3 2 7
100 4.7F 0.01F
01063-006
AD8055
4
6
VOUT 4.7F
100
0.001F -VS
0.01F
01063-009
0.001F -VS
Figure 34. G = +1, RL = 100
Figure 35. G = -1, RL = 100
Rev. J | Page 11 of 16
AD8055/AD8056 APPLICATIONS
FOUR-LINE VIDEO DRIVER
The AD8055 is a useful low cost circuit for driving up to four video lines. For such an application, the amplifier is configured for a noninverting gain of 2, as shown in Figure 36. The input video source is terminated in 75 and is applied to the high impedance noninverting input. Each output cable is connected to the op amp output via a 75 series back termination resistor for proper cable termination. The terminating resistors at the other ends of the lines divide the output signal by 2, which is compensated for by the gain of 2 of the op amp stage. For a single load, the differential gain error of this circuit was measured as 0.01%, with a differential phase error of 0.02. The two load measurements were 0.02% and 0.03, respectively. For four loads, the differential gain error is 0.02%, while the differential phase increases to 0.1.
75 +5V 402 75 75
6
Between these points, a feedback resistor can be used to close the loop. As in the case of a conventional op amp inverting gain stage, an input resistor is added to vary the gain. The gain of this circuit from the input to AMP1 output is RF/RI, while the gain to the output of AMP2 is -RF /RI. The circuit therefore creates a balanced differential output signal from a single-ended input. The advantage of this circuit is that the gain can be changed by changing a single resistor, while still maintaining the balanced differential outputs.
RF 402 +5V 0.1F
3 8
VIN
RI 402
10F 49.9
AMP1
2
1
+VOUT
402
VOUT1 75
AD8056
VOUT2
402 402 402
402
0.1F
2 7
10F
AD8055
VIN 75
3 4
6
75 0.1F 10F 75 75 75
49.9 AMP2
7 4
VOUT3
-VOUT
5
75
VOUT4
-5V
01063-036
-5V
Figure 37. Single-Ended-to-Differential Line Driver
Figure 36. Four-Line Video Driver
LOW NOISE, LOW POWER PREAMP
The AD8055 makes a good, low cost, low noise, low power preamp. A gain-of-10 preamp can be made with a feedback resistor of 909 and a gain resistor of 100 , as shown in Figure 38. The circuit has a -3 dB bandwidth of 20 MHz.
909 +5V + 10F VOUT
SINGLE-ENDED-TO-DIFFERENTIAL LINE DRIVER
Creating differential signals from single-ended signals is required for driving balanced, twisted pair cables, differential input ADCs, and other applications that require differential signals. This can be accomplished by using an inverting and a noninverting amplifier stage to create the complementary signals. The circuit shown in Figure 37 shows how an AD8056 can be used to make a single-ended-to-differential converter that offers some advantages over the architecture previously mentioned. Each op amp is configured for unity gain by the feedback resistors from the outputs to the inverting inputs. In addition, each output drives the opposite op amp with a gain of -1 by means of the crossed resistors. The result of this is that the outputs are complementary and there is high gain in the overall configuration. Feedback techniques similar to a conventional op amp are used to control the gain of the circuit. From the noninverting input of AMP1 to the output of AMP2 is an inverting gain.
100
0.1F
2 7
AD8055
3 4
6
RS
0.1F -5V
10F
01063-038
Figure 38. Low Noise, Low Power Preamp with G = +10 and BW = 20 MHz
With a low source resistance (< approximately 100 ), the major contributors to the input-referred noise of this circuit are the input voltage noise of the amplifier and the noise of the 100 resistor. These are 6 nV/Hz and 1.2 nV/Hz, respectively. These values yield a total input referred noise of 6.1 nV/Hz.
Rev. J | Page 12 of 16
01063-037
0.1F
10F
AD8055/AD8056
POWER DISSIPATION LIMITS
NORMALIZED GAIN (dB)
5 4 3 2 1 0 -1 -2 -3 -4 1 10 FREQUENCY (MHz) 100 500
01063-039
01063-041
402 402 VIN = 0dBm CL 100 CL = 30pF
With a 10 V supply (total VCC - VEE), the quiescent power dissipation of the AD8055 in the SOT-23-5 package is 65 mW, while the quiescent power dissipation of the AD8056 in the MSOP-8 is 120 mW. This translates into a 15.6C rise above the ambient for the SOT-23-5 package and a 24C rise for the MSOP-8 package. The power dissipated under heavy load conditions is approximately equal to the supply voltage minus the output voltage, times the load current, plus the quiescent power previously computed. The total power dissipation is then multiplied by the thermal resistance of the package to find the temperature rise, above ambient, of the part. The junction temperature should be kept below 150C. The AD8055 in the SOT-23-5 package can dissipate 270 mW, while the AD8056 in the MSOP-8 package can dissipate 325 mW (at 85C ambient) without exceeding the maximum die temperature. In the case of the AD8056, this is greater than 1.5 V rms into 50 , enough to accommodate a 4 V p-p sine wave signal on both outputs simultaneously. However, because each output of the AD8055 or AD8056 is capable of supplying as much as 110 mA into a short circuit, a continuous shortcircuit condition will exceed the maximum safe junction temperature.
50
CL = 20pF CL = 10pF CL = 0pF
-5 0.3
Figure 39. Capacitive Load Drive
In general, to minimize peaking or to ensure the stability for larger values of capacitive loads, a small series resistor, RS, can be added between the op amp output and the capacitor, CL. For the setup depicted in Figure 40, the relationship between RS and CL was empirically derived and is shown in Figure 41. RS was chosen to produce less than 1 dB of peaking in the frequency response. Note also that after a sharp rise, RS quickly settles to approximately 25 .
402 +5V
RESISTOR SELECTION
Table 3 is a guide for resistor selection for maintaining gain flatness vs. frequency for various values of gain. Table 3.
Gain +1 +2 +5 +10 RF () 0 402 1k 909 RG () 402 249 100 -3 dB Bandwidth (MHz) 300 160 45 20
VIN = 0dBm
0.1F 402
2 7
10F RS FET PROBE VOUT CL
01063-040
AD8055
3 4
6
50 -5V
0.1F
10F
Figure 40. Setup for RS vs. CL
40 35
DRIVING CAPACITIVE LOADS
When driving a capacitive load, most op amps exhibit peaking in the frequency response just before the frequency rolls off. Figure 39 shows the responses for an AD8056 running at a gain of +2, with an 100 load that is shunted by various values of capacitance. It can be seen that under these conditions the part is still stable with capacitive loads of up to 30 pF.
RS ()
30 25 20 15 10 5 0
0
10
20
30 40 CL (pF)
50
60
270
Figure 41. RS vs. CL
Rev. J | Page 13 of 16
AD8055/AD8056 OUTLINE DIMENSIONS
0.400 (10.16) 0.365 (9.27) 0.355 (9.02)
8 1 5
4
0.280 (7.11) 0.250 (6.35) 0.240 (6.10)
PIN 1 0.100 (2.54) BSC 0.210 (5.33) MAX 0.150 (3.81) 0.130 (3.30) 0.115 (2.92) 0.022 (0.56) 0.018 (0.46) 0.014 (0.36) 0.070 (1.78) 0.060 (1.52) 0.045 (1.14) 0.060 (1.52) MAX 0.015 (0.38) MIN
0.325 (8.26) 0.310 (7.87) 0.300 (7.62) 0.195 (4.95) 0.130 (3.30) 0.115 (2.92)
0.015 (0.38) GAUGE PLANE SEATING PLANE 0.430 (10.92) MAX
0.014 (0.36) 0.010 (0.25) 0.008 (0.20)
0.005 (0.13) MIN
COMPLIANT TO JEDEC STANDARDS MS-001-BA CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN. CORNER LEADS MAY BE CONFIGURED AS WHOLE OR HALF LEADS.
Figure 42. 8-Lead Plastic Dual In-Line Package [PDIP] Narrow Body (N-8) Dimensions shown in inches and (millimeters)
5.00 (0.1968) 4.80 (0.1890)
8 5
4.00 (0.1574) 3.80 (0.1497) 1
6.20 (0.2440)
4 5.80 (0.2284)
1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0040)
1.75 (0.0688) 1.35 (0.0532)
0.50 (0.0196) x 45 0.25 (0.0099)
0.51 (0.0201) COPLANARITY SEATING 0.31 (0.0122) 0.10 PLANE
8 0.25 (0.0098) 0 1.27 (0.0500) 0.40 (0.0157) 0.17 (0.0067)
COMPLIANT TO JEDEC STANDARDS MS-012-AA 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.
Figure 43. 8-Lead Standard Small Outline Package [SOIC_N] Narrow Body (R-8) Dimensions shown in millimeters and (inches)
Rev. J | Page 14 of 16
AD8055/AD8056
3.20 3.00 2.80
3.20 3.00 2.80 PIN 1
8
5
1
5.15 4.90 4.65
4
0.65 BSC 0.95 0.85 0.75 0.15 0.00 0.38 0.22 SEATING PLANE 1.10 MAX 8 0 0.80 0.60 0.40
0.23 0.08
COPLANARITY 0.10
COMPLIANT TO JEDEC STANDARDS MO-187-AA
Figure 44. 8-Lead Mini Small Outline Package [MSOP] (RM-8) Dimensions shown in millimeters
2.90 BSC
5
4
1.60 BSC
1 2 3
2.80 BSC
PIN 1 0.95 BSC 1.30 1.15 0.90 1.90 BSC
1.45 MAX
0.22 0.08 10 5 0 0.60 0.45 0.30
0.15 MAX
0.50 0.30
SEATING PLANE
COMPLIANT TO JEDEC STANDARDS MO-178-AA
Figure 45. 5-Lead Small Outline Transistor Package [SOT-23] (RJ-5) Dimensions shown in millimeters
Rev. J | Page 15 of 16
AD8055/AD8056
ORDERING GUIDE
Model AD8055AN AD8055ANZ 1 AD8055AR AD8055AR-REEL AD8055AR-REEL7 AD8055ARZ1 AD8055ARZ-REEL1 AD8055ARZ-REEL71 AD8055ART-R2 AD8055ART-REEL AD8055ART-REEL7 AD8055ARTZ-R21 AD8055ARTZ-REEL71 AD8056AN AD8056ANZ1 AD8056AR AD8056AR-REEL AD8056AR-REEL7 AD8056ARZ1 AD8056ARZ-REEL1 AD8056ARZ-REEL71 AD8056ARM AD8056ARM-REEL AD8056ARM-REEL7 AD8056ARMZ1 AD8056ARMZ-REEL1 AD8056ARMZ-REEL71
1 2
Temperature Range -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C
Package Description 8-Lead PDIP 8-Lead PDIP 8-Lead SOIC_N 8-Lead SOIC_N, 13" Tape and Reel 8-Lead SOIC_N, 7" Tape and Reel 8-Lead SOIC_N 8-Lead SOIC_N, 13" Tape and Reel 8-Lead SOIC_N, 7" Tape and Reel 5-Lead SOT-23, Reel 5-Lead SOT-23, 13" Tape and Reel 5-Lead SOT-23, 7" Tape and Reel 5-Lead SOT-23, Reel 5-Lead SOT-23, 7" Tape and Reel 8-Lead PDIP 8-Lead PDIP 8-Lead SOIC_N 8-Lead SOIC_N, 13" Tape and Reel 8-Lead SOIC_N, 7" Tape and Reel 8-Lead SOIC_N 8-Lead SOIC_N, 13" Tape and Reel 8-Lead SOIC_N, 7" Tape and Reel 8-Lead MSOP 8-Lead MSOP, 13" Tape and Reel 8-Lead MSOP, 7" Tape and Reel 8-Lead MSOP 8-Lead MSOP, 13" Tape and Reel 8-Lead MSOP, 7" Tape and Reel
Package Option N-8 N-8 R-8 R-8 R-8 R-8 R-8 R-8 RJ-5 RJ-5 RJ-5 RJ-5 RJ-5 N-8 N-8 R-8 R-8 R-8 R-8 R-8 R-8 RM-8 RM-8 RM-8 RM-8 RM-8 RM-8
Branding
H3A H3A H3A H3A H07 2
H5A H5A H5A H5A# H5A# H5A#
Z = Pb-free part, # denotes lead-free product may be top or bottom marked. Prior to 0542, parts were branded H3A.
(c)2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. C01063-0-2/06(J)
Rev. J | Page 16 of 16

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