High Speed, G = +2, Low Cost, Triple Op Amp ADA4862-3 PIN CONFIGURATION Ideal for RGB/HD/SD video Supports 1080i/720p resolution High speed −3 dB bandwidth: 300 MHz Slew rate: 750 V/μs Settling time: 9 ns ( 0.5%) 0.1 dB flatness: 65 MHz Differential gain: 0.02% Differential phase: 0.03° Wide supply range: 5 V to 12 V Low power: 5.3 mA/amp Low voltage offset (RTO): 3.5 mV (typ) High output current: 25 mA Also configurable for gains of +1, −1 Power-down POWER DOWN 1 1 POWER DOWN 2 2 POWER DOWN 3 3 +VS 4 +IN 1 5 550Ω 550Ω ADA4862-3 550Ω –IN 1 6 VOUT1 7 14 VOUT2 13 –IN 2 12 +IN 2 11 –VS 10 +IN 3 9 –IN 3 8 VOUT3 550Ω 550Ω 550Ω 05600-001 FEATURES Figure 1. 14-Lead SOIC (R-14) APPLICATIONS Consumer video Professional video Filter buffers GENERAL DESCRIPTION The ADA4862-3 is designed to operate on supply voltages as low as +5 V and up to ±5 V using only 5.3 mA/amp of supply current. To further reduce power consumption, each amplifier is equipped with a power-down feature that lowers the supply current to 200 μA/amp. The ADA4862-3 also consumes less board area because feedback and gain set resistors are on-chip. Having the resistors on chip simplifies layout and minimizes the required board space. 6.1 6.0 VS = +5V 5.9 5.8 5.7 G = +2 RL = 150Ω CL = 4pF VOUT = 2V p-p VS = ±5V 5.6 5.5 5.4 5.3 05600-022 With its combination of low price, excellent differential gain (0.02%), differential phase (0.03°), and 0.1 dB flatness out to 65 MHz, this amplifier is ideal for both consumer and professional video applications. The ADA4862-3 is available in a 14-lead SOIC package and is designed to work in the extended temperature range of −40°C to +105°C. CLOSED-LOOP GAIN (dB) The ADA4862-3 (triple) is a low cost, high speed, internally fixed, G = +2 op amp, which provides excellent overall performance for high definition and RGB video applications. The 300 MHz, G = +2, −3 dB bandwidth, and 750 V/μs slew rate make this amplifier well suited for many high speed applications. The ADA4862-3 can also be configured to operate in gains of G = +1 and G = −1. 5.2 5.1 0.1 1 10 100 1000 FREQUENCY (MHz) Figure 2. Large Signal 0.1 dB Bandwidth for Various Supplies Rev. A 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. 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 Analog Devices, Inc. All rights reserved. ADA4862-3 TABLE OF CONTENTS Features .............................................................................................. 1 Applications..................................................................................... 11 Applications....................................................................................... 1 Using the ADA4862-3 in Gains = +1, −1................................ 11 Pin Configuration............................................................................. 1 Video Line Driver....................................................................... 13 General Description ......................................................................... 1 Single-Supply Operation ........................................................... 13 Revision History ............................................................................... 2 Power Down................................................................................ 13 Specifications..................................................................................... 3 Layout Considerations............................................................... 14 Absolute Maximum Ratings............................................................ 5 Power Supply Bypassing ............................................................ 14 Thermal Resistance ...................................................................... 5 Outline Dimensions ....................................................................... 15 ESD Caution.................................................................................. 5 Ordering Guide .......................................................................... 15 Typical Performance Characteristics ............................................. 6 REVISION HISTORY 8/05—Rev. 0 to Rev. A Changes to Ordering Guide .......................................................... 15 7/05—Revision 0: Initial Version Rev. A | Page 2 of 16 ADA4862-3 SPECIFICATIONS VS = +5 V (@TA = 25oC, G = +2, RL = 150 Ω, unless otherwise noted). Table 1. Parameter DYNAMIC PERFORMANCE –3 dB Bandwidth G = +1 Bandwidth for 0.1 dB Flatness +Slew Rate (Rising Edge) −Slew Rate (Falling Edge) Settling Time to 0.5% DISTORTION/NOISE PERFORMANCE Harmonic Distortion HD2 Harmonic Distortion HD3 Harmonic Distortion HD2 Harmonic Distortion HD3 Voltage Noise (RTO) Current Noise (RTI) Differential Gain Differential Phase Crosstalk DC PERFORMANCE Offset Voltage (RTO) +Input Bias Current Gain Accuracy INPUT CHARACTERISTICS Input Resistance Input Capacitance Input Common-Mode Voltage Range POWER DOWN PIN Input Voltage Bias Current Turn-On Time Turn-Off Time OUTPUT CHARACTERISTICS Output Overdrive Recovery Time (Rise/Fall) Output Voltage Swing Output Voltage Swing Short-Circuit Current POWER SUPPLY Operating Range Total Quiescent Current Quiescent Current /Amplifier Power Supply Rejection Ratio (RTO) +PSR −PSR Conditions Min Typ Max Unit VO = 0.2 V p-p VO = 2 V p-p VO = 0.2 V p-p VO = 2 V p-p VO = 2 V p-p VO = 2 V p-p VO = 2 V step 300 200 620 65 750 600 9 MHz MHz MHz MHz V/μs V/μs ns fC = 1 MHz, VO = 2 V p-p fC = 1 MHz, VO = 2 V p-p fC = 5 MHz, VO = 2 V p-p fC = 5 MHz, VO = 2 V p-p f = 100 kHz f = 100 kHz, +IN −81 −88 −68 −76 10.6 1.4 0.02 0.03 −75 dBc dBc dBc dBc nV/√Hz pA/√Hz % Degrees dB Amplifier 1 driven, Amplifier 2 output measured, f = 1 MHz Referred to output (RTO) −25 −2.5 1.9 +3.5 −0.6 2 +25 +1 2.1 mV μA V/V +IN +IN G = +1 13 2 1 to 4 MΩ pF V Enabled Power down Enabled Power down 0.6 1.8 −3 115 3.5 200 V V μA μA μs ns VIN = +2.25 V to −0.25 V RL = 150 Ω RL = 1 kΩ Sinking or sourcing 85/50 1.2 to 3.8 1 to 4 65 ns V V mA Enabled Power down = +VS +VS = 2 V to 3 V, −VS = −2.5 V +VS = 2.5 V, −VS = −2 V to −3 V Power Down pin = −VS Rev. A | Page 3 of 16 5 14 −52 −49 16 0.2 −55 −52 12 18 0.33 V mA mA dB dB dB ADA4862-3 VS = ±5 V (@TA = +25oC, G = +2, RL = 150 Ω, unless otherwise noted). Table 2. Parameter DYNAMIC PERFORMANCE –3 dB Bandwidth G = +1 Bandwidth for 0.1 dB Flatness +Slew Rate (Rising Edge) −Slew Rate (Falling Edge) Settling Time to 0.5% DISTORTION/NOISE PERFORMANCE Harmonic Distortion HD2 Harmonic Distortion HD3 Harmonic Distortion HD2 Harmonic Distortion HD3 Voltage Noise (RTO) Current Noise (RTI) Differential Gain Differential Phase Crosstalk DC PERFORMANCE Offset Voltage (RTO) +Input Bias Current Gain Accuracy INPUT CHARACTERISTICS Input Resistance Input Capacitance Input Common-Mode Voltage Range POWER DOWN PIN Input Voltage Bias Current Turn-On Time Turn-Off Time OUTPUT CHARACTERISTICS Output Overdrive Recovery Time (Rise/Fall) Output Voltage Swing Output Voltage Swing Short-Circuit Current POWER SUPPLY Operating Range Total Quiescent Current Quiescent Current/Amplifier Power Supply Rejection Ratio (RTO) +PSR −PSR Conditions Min Typ Max Unit VO = 0.2 V p-p VO = 2 V p-p VO = 0.2 V p-p VO = 2 V p-p VO = 2 V p-p VO = 2 V p-p VO = 2 V step 310 260 720 54 1050 830 9 MHz MHz MHz MHz V/μs V/μs ns fC = 1 MHz, VO = 2 V p-p fC = 1 MHz, VO = 2 V p-p fC = 5 MHz, VO = 2 V p-p fC = 5 MHz, VO = 2 V p-p f = 100 kHz f = 100 kHz, +IN −87 −100 −74 −90 10.6 1.4 0.01 0.02 −75 dBc dBc dBc dBc nV/√Hz pA/√Hz % Degrees dB Amplifier 1 driven, Amplifier 2 output measured, f = 1 MHz −25 −2.5 1.9 +2 −0.6 2 +25 +1 2.1 mV μA V/V +IN +IN G = +1 14 2 −3.7 to +3.8 MΩ pF V Enabled Power down Enabled Power down −4.4 −3.2 −3 250 3.5 200 V V μA μA μs ns VIN = ±3.0 V RL = 150 Ω RL = 1 kΩ Sinking or sourcing 85/40 −3.5 to +3.5 −3.9 to +3.9 115 ns V V mA Enabled Power down = +VS +VS = 4 V to 6 V, −VS = −5 V +VS = 5 V, −VS = −4 V to −6 V, Power Down pin = −VS Rev. A | Page 4 of 16 5 14.5 −54 +50.5 17.9 0.3 −57 −54 12 20.5 0.5 V mA mA dB dB dB ADA4862-3 ABSOLUTE MAXIMUM RATINGS Table 3. 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 amplifier’s drive at the output. The quiescent power is the voltage between the supply pins (VS) × the quiescent current (IS). Rating 12.6 V See Figure 3 ±VS −65°C to +125°C −40°C to +105°C JEDEC J-STD-20 150°C PD = Quiescent Power + (Total Drive Power − Load Power) ⎛V V ⎞ V 2 PD = (VS × I S ) + ⎜ S × OUT ⎟ – OUT RL ⎠ RL ⎝ 2 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 4. Thermal Resistance Package Type 14-lead SOIC θJA 90 Unit °C/W Maximum Power Dissipation The maximum safe power dissipation for the ADA4862-3 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. RMS output voltages should be considered. 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 3 shows the maximum safe power dissipation in the package vs. the ambient temperature for the 14-lead SOIC (90°C/W) on a JEDEC standard 4-layer board. θJA values are approximations. 2.5 2.0 1.5 1.0 0.5 05600-036 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) Parameter Supply Voltage Power Dissipation Common-Mode Input Voltage Storage Temperature Operating Temperature Range Lead Temperature Junction Temperature 0 –55 –45 –35 –25 –15 –5 5 15 25 35 45 55 65 75 85 95 105 115 125 AMBIENT TEMPERATURE (°C) Figure 3. Maximum Power Dissipation vs. Temperature for a 4-Layer Board 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. A | Page 5 of 16 ADA4862-3 TYPICAL PERFORMANCE CHARACTERISTICS 8 G = +2 RL = 150Ω CL = 4pF VOUT = 0.2V p-p 200 2.7 VS = +5V VS = +5V 6 4 3 2 0 0.1 VS = ±5V 0 2.5 G = +2 RL = 150Ω CL = 4pF VOUT = 0.2V p-p TIME = 5ns/DIV –100 05600-004 1 2.6 1 10 1000 100 –200 OUTPUT VOLTAGE (V) +VS = 5V, –VS = 0V VS = ±5V 100 2.4 05600-028 5 OUTPUT VOLTAGE (mV) ±VS = 5V CLOSED-LOOP GAIN (dB) 7 2.3 FREQUENCY (MHz) Figure 4. Small Signal Frequency Response for Various Supplies Figure 7. Small Signal Transient Response for Various Supplies 8 G = +2 RL = 150Ω CL = 4pF VOUT = 2V p-p 200 150 VS = ±5V 6 CL = 9pF 100 VS = +5V 4 3 2 0 05600-012 1 10 –150 1000 100 CL = 6pF –50 –100 1 0 0.1 CL = 4pF 50 G = +2 RL = 150Ω CL = 4pF VOUT = 0.2V p-p VS = ±5V TIME = 5ns/DIV –200 FREQUENCY (MHz) 05600-016 5 OUTPUT VOLTAGE (V) CLOSED-LOOP GAIN (dB) 7 Figure 8. Small Signal Transient Response for Various Capacitor Loads Figure 5. Large Signal Frequency Response for Various Supplies 6.1 2.7 6.0 VS = +5V CL = 6pF VS = ±5V 2.6 5.6 5.5 5.4 5.3 2.4 5.2 5.1 0.1 CL = 4pF 2.5 1 10 100 1000 2.3 FREQUENCY (MHz) Figure 6. Large Signal 0.1 dB Bandwidth for Various Supplies G = +2 RL = 150Ω VOUT = 0.2V p-p VS = 5V TIME = 5ns/DIV 05600-014 5.7 G = +2 RL = 150Ω CL = 4pF VOUT = 2V p-p OUTPUT VOLTAGE (V) 5.8 CL = 9pF 05600-022 CLOSED-LOOP GAIN (dB) 5.9 Figure 9. Small Signal Transient Response for Various Capacitor Loads Rev. A | Page 6 of 16 ADA4862-3 VS = +5V 0.5 3.0 VS = ±5V 0 2.5 –0.5 2.0 G = +2 RL = 150Ω CL = 4pF VOUT = 2V p-p TIME = 5ns/DIV –1.0 –1.5 INPUT VOLTAGE × 2 4 3 VS = ±5V G = +2 RL = 150Ω CL = 4pF f = 1MHz VOUT 2 1 0 –1 –2 –3 –4 05600-042 3.5 OUTPUT AND INPUT VOLTAGE (V) 1.0 5 OUTPUT VOLTAGE (V) +VS = 5V, –VS = 0V 4.0 –5 1.5 05600-010 OUTPUT VOLTAGE (V) ±VS = 5V 6 1.5 1.0 –6 0 100 200 300 400 500 600 700 800 900 1000 TIME (ns) Figure 13. Input Overdrive Recovery Figure 10. Large Signal Transient Response for Various Supplies 5.5 1.5 5.0 0.5 0 –0.5 –1.0 G = +2 RL = 150Ω CL = 4pF VOUT = 2V p-p VS = ±5V TIME = 5ns/DIV –1.5 4.0 CL = 9pF CL = 6pF CL = 4pF 3.0 2.5 1.0 G = +2 RL = 150Ω CL = 4pF VOUT = 2V p-p VS = 5V TIME = 5ns/DIV 05600-019 OUTPUT VOLTAGE (V) 3.5 1.5 VOUT 3.5 3.0 2.5 2.0 1.5 1.0 0.5 –0.5 0 100 200 300 400 500 600 700 TIME (ns) Figure 11. Large Signal Transient Response for Various Capacitor Loads 2.0 4.0 0 05600-018 OUTPUT VOLTAGE (V) CL = 4pF 4.5 VS = 5V G = +2 RL = 150Ω CL = 4pF f = 1MHz 05600-041 OUTPUT AND INPUT VOLTAGE (V) CL = 9pF CL = 6pF 1.0 INPUT VOLTAGE × 2 Figure 12. Large Signal Transient Response for Various Capacitor Loads Rev. A | Page 7 of 16 Figure 14. Output Overdrive Recovery 800 900 1000 ADA4862-3 20 VS = ±5V, +5V G = +2 VOUT = 2V p-p RL =150Ω CL = 4pF 10 VOUT EXPANDED VIN 5 0 0 –5 –0.5 10 VIN 0.5 5 0 0 –5 VOUT EXPANDED –0.5 VS = ±5V, +5V G = +2 VOUT = 2V p-p RL = 150Ω CL = 4pF –10 –1.0 –1.0 –20 50 –1.5 0 5 10 15 20 25 30 35 40 05600-043 –15 45 –1.5 5 0 10 15 20 Figure 15. Settling Time Falling Edge 35 40 45 –15 –20 50 Figure 18. Settling Time Rising Edge 1600 800 G = +2 VS = ±5V RL = 150Ω CL = 4pF 1400 POSITIVE SLEW RATE G = +2 VS = 5V RL = 150Ω CL = 4pF 700 1200 POSITIVE SLEW RATE 1000 NEGATIVE SLEW RATE 800 600 NEGATIVE SLEW RATE 500 400 300 400 200 200 100 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 0 5.0 4.5 05600-006 SLEW RATE (V/μs) 600 05600-005 0 OUTPUT VOLTAGE STEP (V p-p) 0.5 1.0 1.5 2.0 2.5 3.0 OUTPUT VOLTAGE STEP (V p-p) Figure 16. Slew Rate vs. Output Voltage Figure 19. Slew Rate vs. Output Voltage 100 0 G = +2 RL = 150Ω CL = 4pF VOUT = 2V p-p VS = ±5V VS = +5V CROSSTALK (dB) –20 10 G = +2 RL = 150Ω CL = 4pF VOUT = 2V p-p VS = ±5V VS = +5V –40 –60 –80 1 10 05600-037 –100 100 1k 10k 100k 1M 10M 100M FREQUENCY (Hz) –120 0.1 05600-023 SLEW RATE (V/μs) 30 –10 TIME (ns) TIME (ns) VOLTAGE NOISE (nV/ Hz) 25 VOUT EXPANDED (mV) VOUT AND VIN (V) 0.5 15 1.0 05600-046 VOUT VOUT 15 VOUT AND VIN (V) 1.0 20 1.5 VOUT EXPANDED (mV) 1.5 1 10 FREQUENCY (MHz) Figure 17. Voltage Noise vs. Frequency Referred to Output (RTO) Figure 20. Large Signal Crosstalk Rev. A | Page 8 of 16 100 1000 ADA4862-3 0 19 POWER SUPPLY REJECTION (dB) 17 16 15 4 5 6 7 8 9 10 11 –20 –30 –PSR –40 +PSR –50 –60 –70 0.01 12 05600-051 18 05600-026 TOTAL SUPPLY CURRENT (mA) VS = ±5V –10 0.1 1 10 100 1000 FREQUENCY (MHz) SUPPLY VOLTAGE (V) Figure 23. Power Supply Rejection vs. Frequency Figure 21. Total Supply Current vs. VSUPPLY 0 20 VS = ±2.5V VS = ±5V 18 17 VS = +5V 16 15 14 12 –40 05600-021 13 –25 –10 5 20 35 50 65 80 95 110 125 –10 –20 –PSR –30 +PSR –40 –50 –60 0.01 05600-052 POWER SUPPLY REJECTION (dB) TOTAL SUPPLY CURRENT (mA) 19 0.1 1 10 100 FREQUENCY (MHz) TEMPERATURE (°C) Figure 24. Power Supply Rejection vs. Frequency Figure 22. Total Supply Current at Various Supplies vs. Temperature Rev. A | Page 9 of 16 1000 ADA4862-3 –50 fO = 10MHz –60 –70 DISTORTION (dBc) –70 fO = 5MHz –80 fO = 2MHz –90 fO = 1MHz fO = 10MHz fO = 20MHz –80 –90 fO = 5MHz –100 fO = 2MHz –110 –100 05600-049 –110 1 0 2 3 fO = 1MHz –120 –130 4 1 0 OUTPUT VOLTAGE (V p-p) Figure 25. HD2 vs. Frequency vs. Output Voltage 3 4 Figure 27. HD3 vs. Frequency vs. Output Voltage –50 –50 fO = 20MHz –60 fO = 10MHz fO = 20MHz –70 DISTORTION (dBc) G = +2 RL = 150Ω CL = 4pF HD2 VS = 5V –60 –70 fO = 5MHz –80 –90 fO = 2MHz fO = 10MHz –80 –90 fO = 5MHz –100 fO = 2MHz –110 fO = 1MHz fO = 1MHz –100 05600-050 DISTORTION (dBc) 2 OUTPUT VOLTAGE (V p-p) –110 0 0.5 1.0 1.5 2.0 2.5 –120 G = +2 RL = 150Ω CL = 4pF HD3 VS = +5V –130 0 0.5 1.0 1.5 2.0 OUTPUT VOLTAGE (V p-p) OUTPUT VOLTAGE (V p-p) Figure 28. HD3 vs. Frequency vs. Output Voltage Figure 26. HD2 vs. Frequency vs. Output Voltage Rev. A | Page 10 of 16 05600-048 DISTORTION (dBc) –60 G = +2 RL = 150Ω CL = 4pF HD3 VS = ±5V fO = 20MHz G = +2 RL = 150Ω CL = 4pF HD2 VS = ±5V 05600-054 –50 2.5 ADA4862-3 APPLICATIONS 4 The ADA4862-3 was designed to offer outstanding video performance, simplify applications, and minimize board area. 3 The ADA4862-3 is a triple amplifier with on-chip feedback and gain set resistors. The gain is fixed internally at G = +2. The inclusion of the on-chip resistors not only simplifies the design of the application but also eliminates six surface-mount resistors, saving valuable board space and lowers assembly costs. A typical schematic is shown in Figure 29. CLOSED-LOOP GAIN (dB) USING THE ADA4862-3 IN GAINS = +1, −1 G = +1 RL = 150Ω CL = 4pF VOUT = 200mV p-p VS = +5V 2 1 VS = ±5V 0 –1 –2 10μF –4 0.1 05600-053 –3 +VS 1 10 100 1000 FREQUENCY (MHz) 0.01μF Figure 31. Small Signal Unity Gain 3 VOUT VIN 2 RT CLOSED-LOOP GAIN (dB) 0.01μF 10μF 05600-029 –VS GAIN OF +2 Figure 29. Noninverting Configuration (G = +2) 1 G = +1 RL = 150Ω CL = 4pF VOUT = 2V p-p VS = ±5V 0 –1 VS = +5V –2 –3 –5 –6 0.1 1 10 100 1000 FREQUENCY (MHz) Unity-Gain Operation (Option 1) Figure 32. Large Signal Gain +1 10μF 0.01μF CL = 9pF 1.5 CL = 6pF CL = 4pF 1.0 0.5 0 –0.5 –1.0 –1.5 VOUT –2.0 G = +1 RL = 150Ω VOUT = 2V p-p VS = ±5V TIME = 5ns/DIV 05600-020 +VS 2.0 OUTPUT VOLTAGE (V) There are two options for obtaining unity gain (G = +1). The first is shown in Figure 30. In this configuration, the –IN input pin is left floating (feedback is provided via the internal 550 Ω), and the input is applied to the noninverting input. The noise gain for this configuration is 1. Frequency performance and transient response are shown in Figure 31 through Figure 33. VIN 05600-002 –4 While the ADA4862-3 has a fixed gain of G = +2, it can be used in other gain configurations, such as G = −1 and G = +1, which are discussed next. RT 0.01μF Figure 33. Large Signal Transient Response for Various Capacitor Loads GAIN OF +1 05600-032 10μF –VS Figure 30. Unity Gain of Option 1 Rev. A | Page 11 of 16 ADA4862-3 200 Option 2 ⎛ − RF VO = V i ⎜⎜ ⎝ RG ⎞ ⎛ R + RG ⎟ +Vi⎜ F ⎟ ⎜ R G ⎠ ⎝ ⎞ ⎟ ⎟ ⎠ 150 OUTPUT VOLTAGE (mV) G = +1 VS = ±5V RL = 150Ω TIME = 2ns/DIV 100 50 0 –50 –100 –150 05600-039 Another option exists for running the ADA4862-3 as a unitygain amplifier. In this configuration, the noise gain is 2, see Figure 34. The frequency response and transient response for this configuration closely match the gain of +2 plots because the noise gains are equal. This method does have twice the noise gain of Option 1; however, in applications that do not require low noise, Option 2 offers less peaking and ringing. By tying the inputs together, the net gain of the amplifier becomes 1. Equation 1 shows the transfer characteristic for the schematic shown in Figure 34. Frequency and transient response are shown in Figure 35 and Figure 36. –200 (1) Figure 36. Small Signals Transient Response of Option 2 +VS which simplifies to VO = Vi. 10μF +VS 0.01μF 10μF VIN 0.01μF VOUT RT RF RG 0.01μF VOUT VIN –VS 0.01μF GAIN OF –1 10μF 05600-030 Figure 37. Inverting Configuration (G = −1) GAIN OF +1 2.0 1.5 Figure 34. Unity Gain of Option 2 CL = 6pF OUTPUT VOLTAGE (V) 1 0 G = +1 RL = 150Ω 1.0 0.5 –0.5 –1.0 –4 –1.5 –5 –2.0 –7 0.1 1 10 100 CL = 4pF 0 –3 05600-027 GAIN (dB) –2 –6 CL = 9pF G = –1 RL = 150Ω VOUT = 2V p-p VS = ±5V TIME = 5ns/DIV 05600-017 –VS –1 05600-031 10μF RT Figure 38. Large Signal Transient Response for Various Capacitor Loads 1000 FREQUENCY (MHz) Figure 35. Frequency Response of Option 2 Rev. A | Page 12 of 16 ADA4862-3 VIDEO LINE DRIVER SINGLE-SUPPLY OPERATION The ADA4862-3 was designed to excel in video driver applications. Figure 39 shows a typical schematic for a video driver operating on a bipolar supplies. The ADA4862-3 can also operate in single-supply applications. Figure 42 shows the schematic for a single 5 V supply video driver. Resistors R2 and R4 establish the midsupply reference. Capacitor C2 is the bypass capacitor for the midsupply reference. Capacitor C1 is the input coupling capacitor, and C6 is the output coupling capacitor. Capacitor C5 prevents constant current from being drawn through the internal gain set resistor. Resistor R3 sets the circuits ac input impedance. +VS 10μF 0.1μF – 75Ω ADA4862-3 75Ω CABLE VOUT 0.1μF + For more information on single-supply operation of op amps, see www.analog.com/library/analogDialogue/archives/3502/avoiding/. 75Ω 10μF 75Ω CABLE VIN +5V 05600-033 –VS 75Ω C2 1μF C3 2.2μF R4 50kΩ C4 0.01μF Figure 39. Video Driver Schematic In applications that require two video loads be driven simultaneously, the ADA4862-3 can deliver. Figure 40 shows the ADA4862-3 configured with dual video loads. Figure 41 shows the dual video load performance. +VS 10μF 75Ω +5V R2 50kΩ R3 1kΩ C6 220μF VIN R1 50Ω C1 22μF R5 75Ω 75Ω CABLE VOUT R6 75Ω VOUT1 – 7 75Ω C5 22μF 75Ω CABLE VOUT2 8 1 0.1μF POWER DOWN 75Ω CABLE –VS 75Ω 10μF 05600-034 VIN Figure 40. Video Driver Schematic for Two Video Loads 8 CLOSED-LOOP GAIN (dB) 7 Figure 42. Single-Supply Video Driver Schematic 75Ω 6 + G = +2 RL = 75Ω CL = 4pF VOUT = 2V p-p VS = ±5V 6 5 VS = +5V The ADA4862-3 is equipped with an independent Power Down pin for each amplifier allowing the user to reduce the supply current when an amplifier is inactive. The voltage applied to the −VS pin is the logic reference, making single-supply applications useful with conventional logic levels. In a typical 5 V singlesupply application, the −VS pin is connected to analog ground. The amplifiers are powered down when applied logic levels are greater than −VS + 1 V. The amplifiers are enabled whenever the disable pins are left either floating (disconnected) or the applied logic levels are lower than 1 V above −VS. 4 3 2 05600-008 1 0 0.1 1 –VS 05600-035 0.1μF 2 ADA4862-3 75Ω 10 100 1000 FREQUENCY (MHz) Figure 41. Large Signal Frequency Response for Various Supplies, RL = 75 Ω Rev. A | Page 13 of 16 ADA4862-3 LAYOUT CONSIDERATIONS POWER SUPPLY BYPASSING As is the case with all high speed applications, careful attention to printed circuit board layout details prevents associated board parasitics from becoming problematic. Proper RF design technique is mandatory. The PCB should have a ground plane covering all unused portions of the component side of the board to provide a low impedance return path. Removing the ground plane on all layers from the area near the input and output pins reduces stray capacitance. Termination resistors and loads should be located as close as possible to their respective inputs and outputs. Input and output traces should be kept as far apart as possible to minimize coupling (crosstalk) though the board. Adherence to microstrip or stripline design techniques for long signal traces (greater than about 1 inch) is recommended. Careful attention must be paid to bypassing the power supply pins of the ADA4862-3. High quality capacitors with low equivalent series resistance (ESR), such as multilayer ceramic capacitors (MLCCs), should be used to minimize supply voltage ripple and power dissipation. A large, usually tantalum, 10 μF to 47 μF capacitor located in proximity to the ADA4862-3 is required to provide good decoupling for lower frequency signals. In addition, 0.1 μF MLCC decoupling capacitors should be located as close to each of the power supply pins as is physically possible, no more than 1/8 inch away. The ground returns should terminate immediately into the ground plane. Locating the bypass capacitor return close to the load return minimizes ground loops and improves performance. Rev. A | Page 14 of 16 ADA4862-3 OUTLINE DIMENSIONS 8.75 (0.3445) 8.55 (0.3366) 4.00 (0.1575) 3.80 (0.1496) 14 8 1 7 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0039) COPLANARITY 0.10 6.20 (0.2441) 5.80 (0.2283) 1.75 (0.0689) 1.35 (0.0531) 0.51 (0.0201) 0.31 (0.0122) SEATING PLANE 0.50 (0.0197) × 45° 0.25 (0.0098) 8° 0.25 (0.0098) 0° 1.27 (0.0500) 0.40 (0.0157) 0.17 (0.0067) COMPLIANT TO JEDEC STANDARDS MS-012-AB 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. 14-Lead Standard Small Outline Package [SOIC_N] Narrow Body (R-14) Dimensions shown in millimeters and (inches) ORDERING GUIDE Model ADA4862-3YRZ 1 ADA4862-3YRZ-RL1 ADA4862-3YRZ-RL71 1 Temperature Range –40°C to +105°C –40°C to +105°C –40°C to +105°C Package Description 14-Lead SOIC_N 14-Lead SOIC_N 14-Lead SOIC_N Z = Pb-free part. Rev. A | Page 15 of 16 Ordering Quantity 1 2,500 1,000 Package Option R-14 R-14 R-14 ADA4862-3 NOTES © 2005 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D05600–0–8/05(A) Rev. A | Page 16 of 16