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| Low Power, Rail-to-Rail Output, Video Op Amp with Ultralow Power Disable ADA4853-1 FEATURES Ultralow power-down current: 1 A Low quiescent current: 1.4 mA Ideal for standard definition video High speed 100 MHz, -3 dB bandwidth 120 V/s slew rate 0.5 dB flatness: 22 MHz Differential gain: 0.26% Differential phase: 0.10 Single-supply operation Output swings to within 250 mV of either rail Rail-to-rail output Low voltage offset: 2 mV Wide supply range: 2.65 V to 5 V PIN CONFIGURATION VOUT 1 -VS 2 +IN 3 TOP VIEW (Not to Scale) ADA4853-1 6 5 4 +VS POWER DOWN 05884-001 -IN Figure 1. 6-Lead SC70 APPLICATIONS Portable multimedia players Video cameras Digital still cameras Consumer video GENERAL DESCRIPTION The ADA4853-1 is a low power, low cost, high speed, rail-torail output op amp with ultralow power disable that is ideal for portable consumer electronics. Despite its low price, the ADA4853-1 provides excellent overall performance and versatility. The 100 MHz, -3 dB bandwidth and 120 V/s slew rate make this amplifier well suited for many general-purpose, high speed applications. The ADA4853-1 voltage feedback op amp is designed to operate at supply voltages as low as 2.65 V and up to 5 V using only 1.4 mA of supply current. To further reduce power consumption, the amplifier is equipped with a power-down mode, which lowers the supply current to less than 150 nA max, making it ideal in batterypowered applications. The ADA4853-1 provides users with a true single-supply capability, allowing input signals to extend 200 mV below the negative rail and to within 1.2 V of the positive rail. On the output, the amplifier can swing within 150 mV of either supply rail. With its combination of low price, excellent differential gain (0.26%), differential phase (0.10), and 0.5 dB flatness out to 22 MHz, this amplifier is ideal for video applications. Rev. 0 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. The ADA4853-1 is available in a 6-lead SC70 package and is designed to work in the extended industrial temperature range (-40C to +85C). 6.5 6.4 6.3 VS = 5V RL = 150 G = +2 0.1V p-p CLOSED-LOOP GAIN (dB) 6.2 6.1 6.0 5.9 5.8 5.7 5.6 5.5 0.1 1 FREQUENCY (MHz) 10 40 05884-010 2.0V p-p Figure 2. 0.5 dB Flatness 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. ADA4853-1 TABLE OF CONTENTS Features .............................................................................................. 1 Applications....................................................................................... 1 Pin Configuration............................................................................. 1 General Description ......................................................................... 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Specifications with 3 V Supply ................................................... 3 Specifications with 5 V Supply ................................................... 4 Absolute Maximum Ratings............................................................ 5 Thermal Resistance ...................................................................... 5 ESD Caution.................................................................................. 5 Typical Performance Characteristics ..............................................6 Circuit Description......................................................................... 12 Headroom Considerations........................................................ 12 Overload Behavior and Recovery ............................................ 12 Applications..................................................................................... 13 Single-Supply Video Amplifier................................................. 13 Power Supply Bypassing ............................................................ 13 Layout .......................................................................................... 13 Outline Dimensions ....................................................................... 14 Ordering Guide .......................................................................... 14 REVISION HISTORY 1/06--Revision 0: Initial Version Rev. 0 | Page 2 of 16 ADA4853-1 SPECIFICATIONS SPECIFICATIONS WITH 3 V SUPPLY TA = 25C, RF = 1 k, RG = 1 k for G = +2, RL = 150 , unless otherwise noted. Table 1. Parameter DYNAMIC PERFORMANCE -3 dB Bandwidth Bandwidth for 0.1 dB Flatness Settling Time to 0.1% Slew Rate NOISE/DISTORTION PERFORMANCE Differential Gain Differential Phase Input Voltage Noise Input Current Noise DC PERFORMANCE Input Offset Voltage Input Offset Voltage Drift Input Bias Current Input Bias Current Drift Input Bias Offset Current Open-Loop Gain INPUT CHARACTERISTICS Input Resistance Input Capacitance Input Common-Mode Voltage Range Input Overdrive Recovery Time (Rise/Fall) Common-Mode Rejection Ratio POWER-DOWN Power-Down Input Voltage Turn-Off Time Turn-On Time Power-Down Bias Current Enabled Power-Down OUTPUT CHARACTERISTICS Output Overdrive Recovery Time Output Voltage Swing Short-Circuit Current POWER SUPPLY Operating Range Quiescent Current Quiescent Current (Power-Down) Positive Power Supply Rejection Negative Power Supply Rejection Conditions G = +1, VO = 0.1 V p-p G = +2, VO = 2 V p-p G = +2, VO = 2 V p-p, RL = 150 VO = 2 V step G = +2, VO = 2 V step RL = 150 RL = 150 f = 100 kHz f = 100 kHz Min Typ 90 32 8 45 100 0.26 0.10 22 2.2 2 1.6 1.0 4 50 80 0.5/20 0.6 -0.2 to +VCC - 1.2 40 85 1.2 1.2 110 25 0.01 50 0.15 to 2.88 120/100 5 1.4 1.5 30 3.3 1.5 Max Unit MHz MHz MHz ns V/s % Degrees nV/Hz pA/Hz mV V/C A nA/C nA dB M pF V ns dB V s ns A A ns V mA V mA A dB dB 95 VO = 0.5 V to 2.5 V Differential/common mode 72 VIN = -0.5 V to +3.5 V, G = +1 VCM = 0.5 V Power-down 76 Power-down = 3.0 V Power-down = 0 V VIN = -0.25 to +1.75 V, G = +2 RL = 150 Sinking/sourcing 0.3 to 2.8 2.65 1.3 Power-down = low +VS = +1.5 V to +2.5 V, -VS = -1.5 V -VS = -1.5 V to -2.5 V, +VS = +1.5 V -76 -79 -86 -88 Rev. 0 | Page 3 of 16 ADA4853-1 SPECIFICATIONS WITH 5 V SUPPLY TA = 25C, RF = 1 k, RG = 1 k for G = +2, RL = 150 , unless otherwise noted. Table 2. Parameter DYNAMIC PERFORMANCE -3 dB Bandwidth Bandwidth for 0.1 dB Flatness Settling Time to 0.1% Slew Rate NOISE/DISTORTION PERFORMANCE Differential Gain Differential Phase Input Voltage Noise Input Current Noise DC PERFORMANCE Input Offset Voltage Input Offset Voltage Drift Input Bias Current Input Bias Current Drift Input Bias Offset Current Open-Loop Gain INPUT CHARACTERISTICS Input Resistance Input Capacitance Input Common-Mode Voltage Range Input Overdrive Recovery Time (Rise/Fall) Common-Mode Rejection Ratio POWER-DOWN Power-Down Input Voltage Turn-Off Time Turn-On Time Power-Down Bias Current Enabled Power-Down OUTPUT CHARACTERISTICS Output Overdrive Recovery Time Output Voltage Swing Short-Circuit Current POWER SUPPLY Operating Range Quiescent Current Quiescent Current (Power-Down) Positive Power Supply Rejection Negative Power Supply Rejection Conditions G = +1, VO = 0.1 V p-p G = +2, VO = 2 V p-p G = +2, VO = 2 V p-p VO = 2 V step G = +2, VO = 2 V step RL = 150 RL = 150 f = 100 kHz f = 100 kHz Min Typ 100 32 8 54 120 0.33 0.10 22 2.2 2 1.6 1.0 4 60 80 0.5/20 0.6 -0.2 to +VCC - 1.2 40 -88 1.2 0.9 100 40 0.01 50 0.1 to 4.8 135/105 5 1.5 1.5 50 3.3 1.5 Max Unit MHz MHz MHz ns V/s % Degrees nV/Hz pA/Hz mV V/C A nA/C nA dB M pF V ns dB V s ns A A ns V mA V mA A dB dB 100 VO = 0.5 V to 4.5 V Differential/common mode 72 VIN = -0.5 V to +5.5 V, G = +1 VCM = 0.5 V Power-down -79 Power-down = 5 V Power-down = 0 V VIN = -0.25 V to +2.75 V, G = +2 RL = 75 Sinking/sourcing 0.45 to 4.55 2.65 1.4 Power-down = low +VS = +2.5 V to +3.5 V, -VS = -2.5 V -VS = -2.5 V to -3.5 V, +VS = +2.5 V -75 -75 -80 -80 Rev. 0 | Page 4 of 16 ADA4853-1 ABSOLUTE MAXIMUM RATINGS Table 3. Parameter Supply Voltage Power Dissipation Common-Mode Input Voltage Differential Input Voltage Storage Temperature Range Operating Temperature Range Lead Temperature Junction Temperature Rating 5.5 V See Figure 3 -VS + 1 V to +VS - 1 V VS -65C to +125C -40C to +85C JEDEC J-STD-20 150C The power dissipated in the package (PD) for a sine wave and a resistor load is the total power consumed from the supply minus the load power. PD = Total Power Consumed - Load Power PD = VSUPPLY VOLTAGE x I SUPPLY CURRENT - RMS output voltages should be considered. ( ) VOUT 2 RL 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. Airflow increases heat dissipation, effectively reducing JA. In addition, more metal directly in contact with the package leads and through holes under the device reduces JA. Figure 3 shows the maximum safe power dissipation in the package vs. the ambient temperature for the 6-lead SC70 (430C/W) on a JEDEC standard 4-layer board. JA values are approximations. 0.5 THERMAL RESISTANCE MAXIMUM POWER DISSIPATION (W) JA is specified for the worst-case conditions, that is, JA is specified for device soldered in circuit board for surface-mount packages. Table 4. Thermal Resistance Package Type 6-Lead SC70 JA 430 Unit C/W 0.4 0.3 0.2 Maximum Power Dissipation The maximum safe power dissipation for the ADA4853-1 is limited by the associated rise in junction temperature (TJ) on the die. At approximately 150C, which is the glass transition temperature, the plastic changes its properties. Even temporarily exceeding this temperature limit can change the stresses that the package exerts on the die, permanently shifting the parametric performance of the amplifiers. Exceeding a junction temperature of 150C for an extended period can result in changes in silicon devices, potentially causing degradation or loss of functionality. 0.1 05884-044 0 -40 -15 10 35 AMBIENT TEMPERATURE (C) 60 85 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. 0 | Page 5 of 16 ADA4853-1 TYPICAL PERFORMANCE CHARACTERISTICS 2 NORMALIZED CLOSED-LOOP GAIN (dB) 1 0 VS = 5V RL = 150 VOUT = 0.1V p-p 5 G = -1 4 3 CLOSED-LOOP GAIN (dB) VS = 5V RL = 150 VOUT = 0.1V p-p G = +1 CL = 10pF/25 SNUB CL = 10pF CL = 5pF G = +2 -1 -2 -3 -4 05884-006 2 1 0 -1 -2 -3 -4 RSNUB CL 1 RL 10 FREQUENCY (MHz) 100 200 05884-009 05884-011 G = +10 CL = 0pF -5 -6 0.1 -5 -6 0.1 1 10 FREQUENCY (MHz) 100 200 Figure 4. Small Signal Frequency Response for Various Gains 3 2 CLOSED-LOOP GAIN (dB) Figure 7. Small Signal Frequency Response for Various Capacitive Loads 6.5 VS = 5V G = +1 VOUT = 0.1V p-p RL = 75 6.4 6.3 VS = 5V RL = 150 G = +2 0.1V p-p CLOSED-LOOP GAIN (dB) 1 0 -1 -2 -3 -4 -5 05884-007 6.2 6.1 6.0 5.9 5.8 5.7 5.6 05884-010 RL = 1k RL = 150 2.0V p-p -6 0.1 1 10 FREQUENCY (MHz) 100 200 5.5 0.1 1 FREQUENCY (MHz) 10 40 Figure 5. Small Signal Frequency Response for Various Loads 4 3 2 CLOSED-LOOP GAIN (dB) Figure 8. 0.1 dB Flatness Response for Various Output Voltages 1 G = -1 NORMALIZED CLOSED-LOOP GAIN (dB) G = +1 RL = 150 VOUT = 0.1V p-p VS = 3V 0 G = +2 -1 -2 -3 -4 -5 -6 0.1 G = +10 VS = 5V RL = 150 VOUT = 2V p-p 1 0 -1 -2 -3 -4 -5 1 10 FREQUENCY (MHz) VS = 5V 100 200 05884-008 -6 0.1 1 10 FREQUENCY (MHz) 100 1000 Figure 6. Small Signal Frequency Response for Various Supplies Figure 9. Large Signal Frequency Response for Various Gains Rev. 0 | Page 6 of 16 ADA4853-1 7 6 CLOSED-LOOP GAIN (dB) VS = 5V VOUT = 2V p-p G = +2 RL= 75 RL= 1k SLEW RATE (V/s) 250 G = +2 VS = 5V RL = 150 NEGATIVE SLEW RATE 150 POSITIVE SLEW RATE 100 200 5 4 3 2 RL= 150 50 1 05884-012 1 10 FREQUENCY (MHz) 100 1000 0 0.5 1.0 1.5 2.0 2.5 3.0 OUTPUT VOLTAGE STEP (V) 3.5 4.0 Figure 10. Large Signal Frequency Response for Various Loads 5 4 3 CLOSED-LOOP GAIN (dB) Figure 13. Slew Rate vs. Output Voltage 140 120 100 80 60 GAIN 40 20 0 05884-013 OPEN-LOOP GAIN (dB) 2 1 0 -1 -2 -3 -4 -5 -6 0.1 1 10 FREQUENCY (MHz) 100 200 -40C -60 PHASE -90 -120 -150 -180 -210 -240 -20 100 1k 10k 100k 1M 10M 100M FREQUENCY (Hz) Figure 11. Small Signal Frequency Response for Various Temperatures 4 3 2 CLOSED-LOOP GAIN (dB) -20 -30 -40 -50 -60 -70 -80 Figure 14. Open-Loop Gain and Phase vs. Frequency 1 0 -1 -2 -3 -4 -5 05884-014 -40C COMMON-MODE REJECTION (dB) VS = 5V RL = 150 VOUT = 0.1V p-p G = +1 +85C +25C VS = 5V -6 0.1 1 10 FREQUENCY (MHz) 100 200 -90 100 1k 10k 100k 1M 10M 100M FREQUENCY (Hz) Figure 12. Small Signal Frequency Response for Various Temperatures Figure 15. Common-Mode Rejection vs. Frequency Rev. 0 | Page 7 of 16 05884-030 05884-029 OPEN-LOOP PHASE (Degrees) VS = 3V RL = 150 VOUT = 0.1V p-p G = +1 +85C +25C VS = 5V RL = 1k 0 -30 05884-015 0 0.1 0 ADA4853-1 0 VS = 5V -10 POWER SUPPLY REJECTION (dB) -50 -40 G = +2 VS = 5V VOUT = 2V p-p RL = 150 HD3 -20 -PSR -30 -40 -50 -60 -70 05884-031 HARMONIC DISTORTION (dBc) -60 -70 -80 -90 -100 -110 05884-017 RL = 150 HD2 RL = 1k HD3 +PSR RL = 1k HD2 -80 -90 100 1k 10k 100k 1M 10M 100M -120 0.1 FREQUENCY (Hz) 1 FREQUENCY (MHz) 10 Figure 16. Power Supply Rejection vs. Frequency 1000 CLOSED-LOOP OUTPUT IMPEDANCE () Figure 19. Harmonic Distortion vs. Frequency -40 -50 VS = 5V G = +1 G = +1 VS = 5V VOUT = 2V p-p RL = 150 HD3 HARMONIC DISTORTION (dBc) 100 -60 RL = 150 HD2 -70 -80 -90 -100 RL = 1k HD2 -110 -120 0.1 RL = 1k HD3 1 FREQUENCY (MHz) 10 05884-018 10 RL = 75 HD2 RL = 75 HD3 1 0.1 05884-032 0.01 100 1k 10k 100k 1M 10M 100M FREQUENCY (Hz) Figure 17. Output Impedance vs. Frequency Enabled -40 -50 Figure 20. Harmonic Distortion vs. Frequency -40 -50 HARMONIC DISTORTION (dBc) G = +2 VS = 3V VOUT = 2V p-p HARMONIC DISTORTION (dBc) RL = 150 HD2 RL = 150 HD3 G = +1 VS = 5V RL = 150 f = 100kHz 2V 5V -60 -70 -80 -90 -100 -60 -70 -80 -90 -100 HD2 HD3 GND RL = 1k HD3 RL = 1k HD2 1 FREQUENCY (MHz) 10 05884-016 -110 0.1 -120 0 1 2 VOUT (V p-p) 3 4 Figure 18. Harmonic Distortion vs. Frequency Figure 21. Harmonic Distortion for Various Output Voltages Rev. 0 | Page 8 of 16 05884-019 -110 ADA4853-1 2.60 2.58 2.56 G = +2 RL = 150 25ns/DIV 3.75 3.50 VS = 3V 3.25 G = +2 VS = 5V RL = 150 25ns/DIV CL = 0pF, 20pF OUTPUT VOLTAGE (V) 2.54 2.52 2.50 2.48 2.46 2.44 05884-033 OUTPUT VOLTAGE (V) 3.00 2.75 2.50 2.25 2.00 1.75 1.50 1.25 VS = 5V 2.42 2.40 Figure 22. Small Signal Pulse Response for Various Supplies 2.60 2.58 2.56 Figure 25. Large Signal Pulse Response for Various Capacitive Loads 5.5 5.0 INPUT AND OUTPUT VOLTAGE (V) VS = 5V RL = 150 25ns/DIV 2 x INPUT G = +2; CL = 0pF, 20pF 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 OUTPUT G = +2 VS = 5V RL = 1k f = 1MHz OUTPUT VOLTAGE (V) 2.54 2.52 2.50 2.48 2.46 2.44 2.42 2.40 05884-034 G = +1; CL = 15pF 100ns/DIV Figure 23. Small Signal Pulse Response for Various Capacitive Loads 3.75 3.50 3.25 Figure 26. Output Overdrive Recovery 5.5 INPUT AND OUTPUT VOLTAGE (V) G = +2 RL = 150 25ns/DIV 5.0 VS = 3V, 5V INPUT 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 OUTPUT G = +1 VS = 5V RL = 1k f = 1MHz OUTPUT VOLTAGE (V) 3.00 2.75 2.50 2.25 2.00 1.75 1.50 1.25 05884-035 100ns/DIV Figure 24. Large Signal Pulse Response for Various Supplies Figure 27. Input Overdrive Recovery Rev. 0 | Page 9 of 16 05884-021 -0.5 05884-020 -0.5 05884-036 ADA4853-1 1000 -0.6 VS = 5V -0.8 VOLTAGE NOISE (nV/ Hz) 100 VOS (mV) -1.0 -1.2 -1.4 -1.6 -1.8 05884-022 05884-026 10 05884-037 1 10 100 1k 10k 100k 1M 10M -2.0 -1.0 -0.5 0 0.5 1.0 FREQUENCY (Hz) 1.5 2.0 VCM (V) 2.5 3.0 3.5 4.0 4.5 Figure 28. Voltage Noise vs. Frequency 100 1.5 Figure 31. VOS vs. Common-Mode Voltage VS = 5V, T = +85C CURRENT NOISE (pA/ Hz) SUPPLY CURRENT (mA) 1.0 VS = 5V, T = +25C V = 5V, T = -40C VS = 3V, T = -40C S VS = 3V, T = +25C VS = 3V, T = +85C 10 0.5 100 1k 10k 100k 1M 10M 0 0.5 1.0 FREQUENCY (Hz) 1.5 2.0 2.5 3.0 3.5 POWER DOWN VOLTAGE (V) 4.0 4.5 5.0 Figure 29. Current Noise vs. Frequency 20 18 16 14 12 -0.6 Figure 32. Supply Current vs. POWER DOWN Voltage INPUT OFFSET VOLTAGE (mV) VS = 5V N = 155 x = -0.370mV = 0.782 -0.7 VS = 5V COUNT VS = 3V -0.8 10 8 6 4 2 0 -4 -3 -2 -1 0 1 2 3 4 05884-042 -0.9 -1.0 -50 -25 VOFFSET (mV) 0 25 50 TEMPERATURE (C) 75 100 Figure 30. VOS Distribution Figure 33. Input Offset Voltage vs. Temperature Rev. 0 | Page 10 of 16 05884-023 1 10 05884-038 0 ADA4853-1 -0.70 -0.72 OUTPUT SATURATION VOLTAGE (V) 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 -VSAT +VSAT VS = 5V -0.74 INPUT CURRENT (A) -0.76 -0.78 -0.80 -0.82 -0.84 -0.86 -0.88 VS = 3V VS = 5V +IB VS = 3V -IB -0.90 -50 -25 0 25 50 TEMPERATURE (C) 75 100 05884-027 0 5 10 15 20 25 30 35 40 45 50 LOAD CURRENT (mA) Figure 34. Input Bias Current vs. Temperature 3.0 VS = 3V 2.8 OUTPUT VOLTAGE (V) Figure 37. Output Saturation Voltage vs. Load Current 3.0 POSITIVE SWING LOAD RESISTANCE TIED TO MIDSUPPLY 3.1 2.9 2.8 2.7 VOLTAGE (V) VS = 5V RL = 150 2VINPUT VOUTPUT 2.6 05884-041 2.4 0.6 2.6 2.5 2.4 2.3 2.2 2VINPUT - VOUTPUT 0.001 (+0.1%) -0.001 (-0.1%) 0.4 0.2 NEGATIVE SWING 0 10 100 1k 05884-039 2.1 2.0 1.9 0 05884-045 10k LOAD RESISTANCE () 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 TIME (ns) Figure 35. Output Swing vs. Load Resistance 5.0 VS = 5V POWER DOWN PIN VOLTAGE (V) 6 Figure 38. 0.1% Settling Time 3 POWER DOWN G = +2 VS = 5V fIN = 100kHz 4.8 OUTPUT VOLTAGE (V) POSITIVE SWING LOAD RESISTANCE TIED TO MIDSUPPLY 5 4 3 2 1 0 -1 VOUT 4.6 4.4 0.6 1 0.4 0.2 NEGATIVE SWING 0 10 100 1k 05884-040 0 05884-046 10k 0 1 2 3 4 5 TIME (s) 6 7 8 9 10 LOAD RESISTANCE () Figure 36. Output Swing vs. Load Resistance Figure 39. Enable/Disable Time Rev. 0 | Page 11 of 16 OUTPUT VOLTAGE (V) 2 2VINPUT - VOUTPUT (V) ADA4853-1 CIRCUIT DESCRIPTION The ADA4853-1 features a high slew rate input stage that is a true single-supply topology, capable of sensing signals at or below the minus supply rail. The rail-to-rail output stage can pull within 100 mV of either supply rail when driving light loads and within 0.22 V when driving 150 . High speed performance is maintained at supply voltages as low as 2.65 V. For signals approaching the minus supply and inverting gain and high positive gain configurations, the headroom limit is the output stage. The ADA4853-1 uses a common emitter output stage. This output stage maximizes the available output range, limited by the saturation voltage of the output transistors. The saturation voltage increases with the drive current that the output transistor is required to supply due to the output transistor's collector resistance. As the saturation point of the output stage is approached, the output signal shows increasing amounts of compression and clipping. As in the input headroom case, higher frequency signals require a bit more headroom than the lower frequency signals. Figure 21 illustrates this point by plotting the typical distortion vs. the output amplitude. HEADROOM CONSIDERATIONS This amplifier is designed for use in low voltage systems. To obtain optimum performance, it is useful to understand the behavior of the amplifiers as input and output signals approach the amplifier's headroom limits. The amplifier's input commonmode voltage range extends from the negative supply voltage (actually 200 mV below this), or from ground for single-supply operation, to within 1.2 V of the positive supply voltage. Exceeding the headroom limit is not a concern for any inverting gain on any supply voltage, as long as the reference voltage at the amplifier's positive input lies within the amplifier's input common-mode range. The input stage is the headroom limit for signals approaching the positive rail. Figure 40 shows a typical offset voltage vs. the input common-mode voltage for the ADA4853-1 on a 5 V supply. Accurate dc performance is maintained from approximately 200 mV below the minus supply to within 1.2 V of the positive supply. For high speed signals, however, there are other considerations. As the common-mode voltage gets within 1.2 V of positive supply, the amplifier responds well but the bandwidth begins to drop as the common-mode voltage approaches the positive supply. This can manifest itself in increased distortion or settling time. Higher frequency signals require more headroom than the lower frequencies to maintain distortion performance. -0.6 VS = 5V -0.8 -1.0 VOS (mV) OVERLOAD BEHAVIOR AND RECOVERY Input The specified input common-mode voltage of the ADA4853-1 is 200 mV below the negative supply to within 1.2 V of the positive supply. Exceeding the top limit results in lower bandwidth and increased rise time. Pushing the input voltage of a unitygain follower to less than 1.2 V from the positive supply leads to an increasing amount of output error as well as a much increased settling time. The recovery time from input voltages 1.2 V or closer to the positive supply is approximately 40 ns, which is limited by the settling artifacts caused by transistors in the input stage coming out of saturation. The amplifiers do not exhibit phase reversal, even for input voltages beyond the voltage supply rails. Going more than 0.6 V beyond the power supplies turns on protection diodes at the input stage, which greatly increases the current draw of the devices. -1.2 -1.4 -1.6 -1.8 05884-022 -2.0 -1.0 -0.5 0 0.5 1.0 1.5 2.0 VCM (V) 2.5 3.0 3.5 4.0 4.5 Figure 40. VOS vs. Common-Mode Voltage, VS = 5 V Rev. 0 | Page 12 of 16 ADA4853-1 APPLICATIONS SINGLE-SUPPLY VIDEO AMPLIFIER With low differential gain and phase errors and wide 0.1 dB flatness, the ADA4853-1 is an ideal solution for video applications. Figure 41 shows a typical video driver set for a noninverting gain of +2, where RF = RG = 1 k. The video amplifier input is terminated into a shunt 75 resistor. At the output, the amplifier has a series 75 resistor for impedance matching to the video load. When operating in low voltage, single-supply applications, the input signal is only limited by the input stage headroom. RF +VS C1 2.2F + RG PD U1 VIN C2 0.01F V LAYOUT As is the case with all high speed applications, careful attention to printed circuit board (PCB) layout details prevents associated board parasitics from becoming problematic. The ADA4853-1 can operate up to 100 MHz; therefore, proper RF design techniques must be employed. 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 and under the input and output pins reduces stray capacitance. Signal lines connecting the feedback and gain resistors should be kept as short as possible to minimize the inductance and stray capacitance associated with these traces. 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) through the board. Adherence to microstrip or stripline design techniques for long signal traces (greater than 1 inch) is recommended. For more information on high speed board layout, go to: www.analog.com and www.analog.com/library/analogDialogue/archives/3909/layout.html. 75 75 CABLE VOUT 05884-043 75 Figure 41. Video Amplifier POWER SUPPLY BYPASSING Attention must be paid to bypassing the power supply pins of the ADA4853-1. 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, 2.2 F to 47 F capacitor located in proximity to the ADA4853-1 is required to provide good decoupling for lower frequency signals. The actual value is determined by the circuit transient and frequency requirements. In addition, 0.1 F MLCC decoupling capacitors should be located as close to each of the power supply pins as is physically possible, no more than 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. 0 | Page 13 of 16 ADA4853-1 OUTLINE DIMENSIONS 2.20 2.00 1.80 2.40 2.10 1.80 1.35 1.25 1.15 PIN 1 1.30 BSC 1.00 0.90 0.70 6 1 5 2 4 3 0.65 BSC 1.10 0.80 0.40 0.10 0.46 0.36 0.26 0.10 MAX 0.30 0.15 0.10 COPLANARITY SEATING PLANE 0.22 0.08 COMPLIANT TO JEDEC STANDARDS MO-203-AB Figure 42. 6-Lead Thin Shrink Small Outline Transistor Package [SC70] (KS-6) Dimensions shown in millimeters ORDERING GUIDE Model ADA4853-1AKSZ-R2 1 ADA4853-1AKSZ-R71 ADA4853-1AKSZ-RL1 1 Temperature Range -40C to +85C -40C to +85C -40C to +85C Package Description 6-Lead Thin Shrink Small Outline Transistor Package (SC70) 6-Lead Thin Shrink Small Outline Transistor Package (SC70) 6-Lead Thin Shrink Small Outline Transistor Package (SC70) Ordering Quantity 250 3,000 10,000 Package Option KS-6 KS-6 KS-6 Branding HEC HEC HEC Z = Pb-free part. Rev. 0 | Page 14 of 16 ADA4853-1 NOTES Rev. 0 | Page 15 of 16 ADA4853-1 NOTES (c)2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D05884-0-1/06(0) Rev. 0 | Page 16 of 16 |
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