LT1229/LT1230 Dual and Quad 100MHz Current Feedback Amplifiers U FEATURES DESCRIPTIO The LT(R)1229/LT1230 dual and quad 100MHz current feedback amplifiers are designed for maximum performance in small packages. Using industry standard pinouts, the dual is available in the 8-pin miniDIP and the 8-pin SO package while the quad is in the 14-pin DIP and 14-pin SO. The amplifiers are designed to operate on almost any available supply voltage from 4V (2V) to 30V (15V). 100MHz Bandwidth 1000V/s Slew Rate Low Cost 30mA Output Drive Current 0.04% Differential Gain 0.1 Differential Phase High Input Impedance: 25M, 3pF Wide Supply Range: 2V to 15V Low Supply Current: 6mA Per Amplifier Inputs Common Mode to Within 1.5V of Supplies Outputs Swing Within 0.8V of Supplies These current feedback amplifiers have very high input impedance and make excellent buffer amplifiers. They maintain their wide bandwidth for almost all closed-loop voltage gains. The amplifiers drive over 30mA of output current and are optimized to drive low impedance loads, such as cables, with excellent linearity at high frequencies. U APPLICATIO S Video Instrumentation Amplifiers Cable Drivers RGB Amplifiers Test Equipment Amplifiers The LT1229/LT1230 are manufactured on Linear Technology's proprietary complementary bipolar process. For a single amplifier like these see the LT1227 and for better DC accuracy see the LT1223. , LTC and LT are registered trademarks of Linear Technology Corporation. U TYPICAL APPLICATIO Loop Through Amplifier Frequency Response Video Loop Through Amplifier R G1 3.01k R F1 750 R G2 187 10 R F2 750 0 NORMAL SIGNAL - 3.01k VIN - 1/2 LT1229 + - 3.01k VIN+ 12.1k 1/2 LT1229 + 12.1k BNC INPUTS HIGH INPUT RESISTANCE DOES NOT LOAD CABLE EVEN WHEN POWER IS OFF VOUT GAIN (dB) -10 -20 -30 1% RESISTORS WORST CASE CMRR = 22dB TYPICALLY = 38dB -40 VOUT = G (VIN+ - VIN - ) R F1 = RF2 -60 R G1 = (G - 1) RF2 R F2 RG2 = G-1 COMMON MODE SIGNAL -50 10 100 1k 10k 100k 1M 10M 100M FREQUENCY (Hz) LT1229 * TA02 TRIM CMRR WITH RG1 LT1229 * TA01 1 LT1229/LT1230 W W W AXI U U ABSOLUTE RATI GS (Note 1) Supply Voltage ...................................................... 18V Input Current ...................................................... 15mA Output Short Circuit Duration (Note 2) ......... Continuous Operating Temperature Range LT1229C, LT1230C ............................... 0C to 70C LT1229M, LT1230M (OBSOLETE).. -55C to 125C Storage Temperature Range ..................-65C to 150C Junction Temperature Plastic Package .............................................. 150C Ceramic Package (OBSOLETE) ................ 175C Lead Temperature (Soldering, 10 sec.)................. 300C U W U PACKAGE/ORDER I FOR ATIO ORDER PART NUMBER TOP VIEW OUT A 1 -IN A 2 8 V+ 7 OUT B 6 -IN B 5 +IN B A +IN A 3 V- 4 B LT1229CN8 LT1229CS8 S8 PART MARKING N8 PACKAGE S8 PACKAGE 8-LEAD PLASTIC DIP 8-LEAD PLASTIC SOIC TJ MAX = 150C, JA = 100C/W (N8) TJ MAX = 150C, JA = 150C/W (S8) 1229 J8 PACKAGE 8-LEAD CERAMIC DIP TJ MAX = 175C, JA = 100C/W (J8) ORDER PART NUMBER TOP VIEW OUT A 1 -IN A 2 +IN A 3 V+ 4 +IN B 5 -IN B 6 OUT B 7 14 OUT D 13 -IN D A D 12 +IN D 11 V - ORDER PART NUMBER LT1230CN LT1230CS 10 +IN C B C 9 -IN C 8 OUT C N PACKAGE S PACKAGE 14-LEAD PLASTIC DIP 14-LEAD PLASTIC SOIC TJ MAX = 150C, JA = 70C/W (N) TJ MAX = 150C, JA = 110C/W (S) J PACKAGE 14-LEAD CERAMIC DIP TJ MAX = 175C, JA = 80C/W (J) ORDER PART NUMBER LT1230MJ LT1230CJ LT1229MJ8 LT1229CJ8 OBSOLETE PACKAGE OBSOLETE PACKAGE Consider the N Package for Alternate Source Consider the N Package for Alternate Source Consult LTC Marketing for parts specified with wider operating temperature ranges. 2 LT1229/LT1230 ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. Each Amplifier, VCM = 0V, 5V VS = 15V, pulse tested unless otherwise noted. SYMBOL PARAMETER CONDITIONS VOS Input Offset Voltage TA = 25C MIN TYP MAX UNITS 3 10 15 mV mV Input Offset Voltage Drift IIN + Noninverting Input Current TA = 25C 0.3 3 10 A A 10 50 100 A A IIN- Inverting Input Current V/C 10 TA = 25C en Input Noise Voltage Density f = 1kHz, RF = 1k, RG = 10, RS = 0 3.2 nV/Hz +in Noninverting Input Noise Current Density f = 1kHz, RF = 1k, RG = 10, RS = 10k 1.4 pA/Hz -in Inverting Input Noise Current Density f = 1kHz RIN Input Resistance VIN = 13V, VS = 15V VIN = 3V, VS = 5V CIN Input Capacitance Input Voltage Range VS = 15V, TA = 25C VS = 5V, TA = 25C CMRR Common Mode Rejection Ratio Inverting Input Current Common Mode Rejection PSRR VS = 15V, VCM = 13V, TA = 25C VS = 15V, VCM = 12V VS = 5V, VCM = 3V, TA = 25C VS = 5V, VCM = 2V VS = 15V, VCM = 13V, TA = 25C VS = 15V, VCM = 12V VS = 5V, VCM = 3V, TA = 25C VS = 5V, VCM = 2V pA/Hz 25 25 M M 3 pF 13 12 3 2 13.5 V V V V 55 55 55 55 69 3.5 2.5 2.5 Noninverting Input Current Power Supply Rejection VS = 2V to 15V, TA = 25C VS = 3V to 15V Inverting Input Current Power Supply Rejection VS = 2V to 15V, TA = 25C VS = 3V to 15V 60 60 dB dB dB dB 69 VS = 2V to 15V, TA = 25C VS = 3V to 15V Power Supply Rejection Ratio 32 2 2 10 10 10 10 80 A/V A/V A/V A/V dB dB 10 50 50 nA/V nA/V 0.1 5 5 A/V A/V 3 LT1229/LT1230 ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. Each Amplifier, VCM = 0V, 5V VS = 15V, pulse tested unless otherwise noted. SYMBOL PARAMETER CONDITIONS AV Large-Signal Voltage Gain, (Note 3) VS = 15V, VOUT = 10V, RL = 1k VS = 5V, VOUT = 2V, RL = 150 ROL Transresistance, VOUT/IIN-, (Note 3) VS = 15V, VOUT = 10V, RL = 1k VS = 5V, VOUT = 2V, RL = 150 VOUT Maximum Output Voltage Swing, (Note 3) VS = 15V, RL = 400, TA = 25C MIN TYP 55 55 65 65 dB dB 100 100 200 200 k k 12 10 3 2.5 13.5 30 65 125 mA 6 9.5 11 mA mA VS = 5V, RL = 150, TA = 25C IOUT Maximum Output Current RL = 0, TA = 25C IS Supply Current, (Note 4) VOUT = 0V, Each Amplifier, TA = 25C Slew Rate, (Notes 5 and 7) TA = 25C SR Slew Rate tr Rise Time, (Notes 6 and 7) BW Small-Signal Bandwidth tr ts 700 V/s VS = 15V, RF = 750, RG= 750, RL = 400 TA = 25C 2500 V/s 100 MHz Small-Signal Rise Time VS = 15V, RF = 750, RG= 750, RL = 100 VS = 15V, RF = 750, RG= 750, RL = 100 3.5 ns Propagation Delay VS = 15V, RF = 750, RG= 750, RL = 100 3.5 ns Small-Signal Overshoot VS = 15V, RF = 750, RG= 750, RL = 100 0.1%, VOUT = 10V, RF =1k, RG= 1k, RL =1k 15 % 45 ns Settling Time 10 20 ns Differential Gain, (Note 8) VS = 15V, RF = 750, RG= 750, RL = 1k 0.01 % Differential Phase, (Note 8) 0.01 Deg Differential Gain, (Note 8) VS = 15V, RF = 750, RG= 750, RL = 1k VS = 15V, RF = 750, RG= 750, RL = 150 0.04 % Differential Phase, (Note 8) VS = 15V, RF = 750, RG= 750, RL = 150 0.1 Deg Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: A heat sink may be required depending on the power supply voltage and how many amplifiers are shorted. Note 3: The power tests done on 15V supplies are done on only one amplifier at a time to prevent excessive junction temperatures when testing at maximum operating temperature. Note 4: The supply current of the LT1229/LT1230 has a negative temperature coefficient. For more information see the application information section. Note 5: Slew rate is measured at 5V on a 10V output signal while operating on 15V supplies with RF = 1k, RG = 110 and RL = 400. The 4 300 UNITS V V V V 3.7 SR MAX slew rate is much higher when the input is overdriven and when the amplifier is operated inverting, see the applications section. Note 6: Rise time is measured from 10% to 90% on a 500mV output signal while operating on 15V supplies with RF = 1k, RG = 110 and RL = 100. This condition is not the fastest possible, however, it does guarantee the internal capacitances are correct and it makes automatic testing practical. Note 7: AC parameters are 100% tested on the ceramic and plastic DIP packaged parts (J and N suffix) and are sample tested on every lot of the SO packaged parts (S suffix). Note 8: NTSC composite video with an output level of 2VP. LT1229/LT1230 U W TYPICAL PERFOR A CE CHARACTERISTICS Voltage Gain and Phase vs Frequency, Gain = 6dB 160 6 90 140 GAIN 135 4 180 3 225 2 1 PHASE SHIFT (DEG) 5 VS = 15V RL = 100 RF = 750 -2 0.1 160 RF = 500 120 RF = 750 100 80 RF = 1k 60 40 RF = 2k 20 0 1 10 4 6 8 10 14 12 LT1229 * TPC01 21 180 45 160 135 18 180 17 225 16 15 VS = 15V RL = 100 RF = 750 12 0.1 1 -3dB BANDWIDTH (MHz) 90 GAIN PHASE SHIFT (DEG) VOLTAGE GAIN (dB) 0 19 14 10 100 RF = 250 80 RF = 500 RF = 750 60 RF = 1k 40 RF = 2k RF = 750 60 RF = 1k 40 RF = 2k 0 2 4 6 8 10 14 12 16 18 0 2 4 6 8 10 14 12 - 3dB Bandwidth vs Supply Voltage, Gain = 100, RL = 1k 14 -3dB BANDWIDTH (MHz) 16 14 RF = 500 10 RF = 1k 8 6 18 LT1229 * TPC06 90 12 16 SUPPLY VOLTAGE (V) RF = 2k 4 RF = 500 12 RF = 1k 10 8 RF = 2k 6 4 2 0 0 2 4 6 8 10 12 14 16 18 SUPPLY VOLTAGE (V) LT1229 * TPC07 RF = 500 80 18 PHASE SHIFT (DEG) VOLTAGE GAIN (dB) RF = 250 20 2 FREQUENCY (MHz) 18 PEAKING 0.5dB PEAKING 5dB 100 16 225 16 120 18 37 100 14 12 140 45 180 VS = 15V RL = 100 RF = 750 10 - 3dB Bandwidth vs Supply Voltage, Gain = 10, RL = 1k 0 38 35 8 LT1229 * TPC03 - 3dB Bandwidth vs Supply Voltage, Gain = 100, RL = 100 36 6 LT1229 * TPC05 135 10 4 SUPPLY VOLTAGE (V) GAIN 1 2 SUPPLY VOLTAGE (V) 120 0 39 32 0.1 0 0 100 PHASE RF = 2k RF = 1k 160 20 42 34 18 140 Voltage Gain and Phase vs Frequency, Gain = 40dB 33 40 180 LT1229 * TPC04 40 16 PEAKING 0.5dB PEAKING 5dB FREQUENCY (MHz) 41 PEAKING 0.5dB PEAKING 5dB 60 - 3dB Bandwidth vs Supply Voltage, Gain = 10, RL = 100 PHASE 13 80 LT1229 * TPC02 Voltage Gain and Phase vs Frequency, Gain = 20dB 20 100 SUPPLY VOLTAGE (V) FREQUENCY (MHz) 22 RF = 750 120 0 2 0 100 RF = 500 140 20 -3dB BANDWIDTH (MHz) -1 180 PEAKING 0.5dB PEAKING 5dB -3dB BANDWIDTH (MHz) 0 - 3dB Bandwidth vs Supply Voltage, Gain = 2, RL = 1k -3dB BANDWIDTH (MHz) 180 45 PHASE -3dB BANDWIDTH (MHz) 0 7 8 VOLTAGE GAIN (dB) - 3dB Bandwidth vs Supply Voltage, Gain = 2, RL = 100 0 0 2 4 6 8 10 12 14 16 18 SUPPLY VOLTAGE (V) LT1229 * TPC08 LT1229 * TPC09 5 LT1229/LT1230 U W TYPICAL PERFOR A CE CHARACTERISTICS Maximum Capacitance Load vs Feedback Resistor Total Harmonic Distortion vs Frequency 10000 10 RL = 1k PEAKING 5dB GAIN = 2 1 0 1 2 0.01 VO = 7VRMS -70 100 1k FEEDBACK RESISTOR (k) 10k Output Short-Circuit Current vs Junction Temperature -1.5 -2.0 2.0 V - = -2V TO -18V 1.0 0.5 V- -50 -25 0 25 50 75 70 -0.5 -1.0 RL = 2V VS 18V 1.0 0.5 V- -50 -25 100 125 OUTPUT SHORT CIRCUIT CURRENT (mA) OUTPUT SATURATION VOLTAGE (V) COMMON MODE RANGE (V) LT1229 * TPC12 V+ V + = 2V TO 18V 0 25 75 50 100 Spot Noise Voltage and Current vs Frequency 40 30 -50 -25 125 0 POWER SUPPLY REJECTION (dB) en +in 1 1k 10k FREQUENCY (Hz) 100k 75 100 125 150 175 Output Impedance vs Frequency 100 VS = 15V RL = 100 RF = RG = 750 60 POSITIVE 40 NEGATIVE 20 0 10k VS = 15V 10 1.0 RF = RG = 2k RF = RG = 750 0.1 0.01 100k 1M 10M 100M 0.001 10k 100k 1M 10M 100M FREQUENCY (Hz) FREQUENCY (Hz) LT1229 * TPC16 50 LT1229 * TPC15 80 10 25 TEMPERATURE (C) Power Supply Rejection vs Frequency 100 100 50 LT1229 * TPC14 LT1229 * TPC13 10 60 TEMPERATURE (C) TEMPERATURE (C) -in 100 FREQUENCY (MHz) Output Saturation Voltage vs Temperature V+ 1.5 10 LT1229 * TPC11 Input Common Mode Limit vs Temperature SPOT NOISE (nV/Hz OR pA/Hz) 1 100k FREQUENCY (Hz) LT1229 * TPC10 -1.0 3RD -50 -60 10 -0.5 2ND -40 VO = 1VRMS 0.001 3 VS = 15V VO = 2VP-P RL = 100 RF = 750 AV = 10dB -30 OUTPUT IMPEDANCE () CAPACITIVE LOAD (pF) VS = 15V 100 -20 VS = 15V RL = 400 RF = RG = 750 DISTORTION (dBc) VS = 5V TOTAL HARMONIC DISTORTION (%) 0.10 1000 6 2nd and 3rd Harmonic Distortion vs Frequency LT1229 * TPC17 LT1229 * TPC18 LT1229/LT1230 U W TYPICAL PERFOR A CE CHARACTERISTICS Settling Time to 10mV vs Output Step Settling Time to 1mV vs Output Step INVERTING 4 4 OUTPUT STEP (V) 6 VS = 15V RF = RG = 1k 0 NONINVERTING 8 6 2 10 -2 -4 9 8 INVERTING SUPPLY CURRENT (mA) NONINVERTING 8 OUTPUT STEP (V) Supply Current vs Supply Voltage 10 10 2 VS = 15V RF = RG = 1k 0 -2 -4 INVERTING -6 -6 -8 NONINVERTING 0 20 40 60 80 100 0 4 8 12 16 20 SETTLING TIME (s) SETTLING TIME (ns) 125C 4 175C 3 1 -10 -10 25C 6 5 2 NONINVERTING -8 INVERTING -55C 7 0 0 2 4 6 8 10 14 16 18 SUPPLY VOLTAGE (V) LT1229 * TPC20 LT1229 * TPC19 12 LT1229 * TPC21 W W SI PLIFIED SCHE ATIC One Amplifier V+ +IN -IN VOUT V- LT1229 * TA03 7 LT1229/LT1230 U W U UO APPLICATI S I FOR ATIO The LT1229/LT1230 are very fast dual and quad current feedback amplifiers. Because they are current feedback amplifiers, they maintain their wide bandwidth over a wide range of voltage gains. These amplifiers are designed to drive low impedance loads such as cables with excellent linearity at high frequencies. Feedback Resistor Selection The small-signal bandwidth of the LT1229/LT1230 is set by the external feedback resistors and the internal junction capacitors. As a result, the bandwidth is a function of the supply voltage, the value of the feedback resistor, the closed-loop gain and load resistor. The characteristic curves of Bandwidth versus Supply Voltage are done with a heavy load (100) and a light load (1k) to show the effect of loading. These graphs also show the family of curves that result from various values of the feedback resistor. These curves use a solid line when the response has less than 0.5dB of peaking and a dashed line when the response has 0.5dB to 5dB of peaking. The curves stop where the response has more than 5dB of peaking. limited by the gain bandwidth product of about 1GHz. The curves show that the bandwidth at a closed-loop gain of 100 is 10MHz, only one tenth what it is at a gain of two. Capacitance on the Inverting Input Current feedback amplifiers want resistive feedback from the output to the inverting input for stable operation. Take care to minimize the stray capacitance between the output and the inverting input. Capacitance on the inverting input to ground will cause peaking in the frequency response (and overshoot in the transient response), but it does not degrade the stability of the amplifier. The amount of capacitance that is necessary to cause peaking is a function of the closed-loop gain taken. The higher the gain, the more capacitance is required to cause peaking. We can add capacitance from the inverting input to ground to increase the bandwidth in high gain applications. For example, in this gain of 100 application, the bandwidth can be increased from 10MHz to 17MHz by adding a 2200pF capacitor. + VIN Small-Signal Rise Time with RF = RG = 750, VS = 15V, and RL = 100 1/2 LT1229 VOUT - RF 510 RG 5.1 CG LT1229 * TA05 At a gain of two, on 15V supplies with a 750 feedback resistor, the bandwidth into a light load is over 160MHz without peaking, but into a heavy load the bandwidth reduces to 100MHz. The loading has so much effect because there is a mild resonance in the output stage that enhances the bandwidth at light loads but has its Q reduced by the heavy load. This enhancement is only useful at low gain settings; at a gain of ten it does not boost the bandwidth. At unity gain, the enhancement is so effective the value of the feedback resistor has very little effect. At very high closed-loop gains, the bandwidth is Boosting Bandwidth of High Gain Amplifier with Capacitance on Inverting Input 49 46 C G = 4700pF 43 40 GAIN (dB) LT1229 * TA04 C G = 2200pF 37 34 CG = 0 31 28 25 22 19 1 10 100 FREQUENCY (MHz) LT1229 * TA06 8 LT1229/LT1230 U W U UO APPLICATI S I FOR ATIO Capacitive Loads The LT1229/LT1230 can drive capacitive loads directly when the proper value of feedback resistor is used. The graph Maximum Capacitive Load vs Feedback Resistor should be used to select the appropriate value. The value shown is for 5dB peaking when driving a 1k load at a gain of 2. This is a worst case condition; the amplifier is more stable at higher gains and driving heavier loads. Alternatively, a small resistor (10 to 20) can be put in series with the output to isolate the capacitive load from the amplifier output. This has the advantage that the amplifier bandwidth is only reduced when the capacitive load is present, and the disadvantage that the gain is a function of the load resistance. Power Supplies The LT1229/LT1230 amplifiers will operate from single or split supplies from 2V (4V total) to 15V (30V total). It is not necessary to use equal value split supplies, however, the offset voltage and inverting input bias current will change. The offset voltage changes about 350V per volt of supply mismatch, the inverting bias current changes about 2.5A per volt of supply mismatch. Power Dissipation The LT1229/LT1230 amplifiers combine high speed and large output current drive into very small packages. Because these amplifiers work over a very wide supply range, it is possible to exceed the maximum junction temperature under certain conditions. To ensure that the LT1229 and LT1230 remain within their absolute maximum ratings, we must calculate the worst case power dissipation, define the maximum ambient temperature, select the appropriate package and then calculate the maximum junction temperature. The worst case amplifier power dissipation is the total of the quiescent current times the total power supply voltage plus the power in the IC due to the load. The quiescent supply current of the LT1229/LT1230 has a strong negative temperature coefficient. The supply current of each amplifier at 150C is less than 7mA and typically is only 4.5mA. The power in the IC due to the load is a function of the output voltage, the supply voltage and load resistance. The worst case occurs when the output voltage is at half supply, if it can go that far, or its maximum value if it cannot reach half supply. For example, let's calculate the worst case power dissipation in a video cable driver operating on 12V supplies that delivers a maximum of 2V into 150. Pd (MAX) = 2VS IS (MAX) + VS - VO (MAX) ( VO (MAX) RL ) 2V 150 = 0.168 + 0.133 = 0.301W per Amp Now if that is the dual LT1229, the total power in the package is twice that, or 0.602W. We now must calculate how much the die temperature will rise above the ambient. The total power dissipation times the thermal resistance of the package gives the amount of temperature rise. For the above example, if we use the SO8 surface mount package, the thermal resistance is 150C/W junction to ambient in still air. Pd (MAX) = 2 * 12V * 7mA + 12V - 2V * Temperature Rise = Pd (MAX) RJA = 0.602W * 150C/W = 90.3C The maximum junction temperature allowed in the plastic package is 150C. Therefore, the maximum ambient allowed is the maximum junction temperature less the temperature rise. Maximum Ambient = 150C - 90.3C = 59.7C Note that this is less than the maximum of 70C that is specified in the absolute maximum data listing. If we must use this package at the maximum ambient we must lower the supply voltage or reduce the output swing. As a guideline to help in the selection of the LT1229/ LT1230 the following table describes the maximum supply voltage that can be used with each part in cable driving applications. 9 LT1229/LT1230 W U U UO APPLICATI S I FOR ATIO Large-Signal Response, AV = 2, RF = RG = 750 Assumptions: 1. The maximum ambient is 70C for the commercial parts (C suffix) and 125C for the full temperature parts (M suffix). 2. The load is a double-terminated video cable, 150. 3. The maximum output voltage is 2V (peak or DC). 4. The thermal resistance of each package: J8 is 100C/W J is 80/W N8 is 100C/W N is 70/W S8 is 150C/W S is 110/W LT1229 * TA07 Maximum Supply Voltage for 75 Cable Driving Applications at Maximum Ambient Temperature PART PACKAGE MAX POWER AT TA MAX SUPPLY LT1229MJ8 LT1229CJ8 LT1229CN8 LT1229CS8 Ceramic DIP Ceramic DIP Plastic DIP Plastic SO8 0.500W at 125C 1.050W at 70C 0.800W at 70C 0.533W at 70C VS < 10.1 VS < 18.0 VS < 15.6 VS < 10.6 LT1230MJ LT1230CJ LT1230CN LT1230CS Ceramic DIP Ceramic DIP Plastic DIP Plastic SO14 0.625W at 125C 1.313W at 70C 1.143W at 70C 0.727W at 70C VS < 6.6 VS < 13.0 VS < 11.4 VS < 7.6 Larger feedback resistors will reduce the slew rate as will lower supply voltages, similar to the way the bandwidth is reduced. Large-Signal Response, AV = 10, RF = 1k, RG = 110 Slew Rate The slew rate of a current feedback amplifier is not independent of the amplifier gain the way it is in a traditional op amp. This is because the input stage and the output stage both have slew rate limitations. The input stage of the LT1229/LT1230 amplifiers slew at about 100V/s before they become nonlinear. Faster input signals will turn on the normally reverse-biased emitters on the input transistors and enhance the slew rate significantly. This enhanced slew rate can be as much as 2500V/s. The output slew rate is set by the value of the feedback resistors and the internal capacitance. At a gain of ten with a 1k feedback resistor and 15V supplies, the output slew rate is typically 700V/s and - 1000V/s. There is no input stage enhancement because of the high gain. 10 LT1229 * TA08 Settling Time The characteristic curves show that the LT1229/LT1230 amplifiers settle to within 10mV of final value in 40ns to 55ns for any output step up to 10V. The curve of settling to 1mV of final value shows that there is a slower thermal contribution up to 20s. The thermal settling component comes from the output and the input stage. The output contributes just under 1mV per volt of output change and the input contributes 300V per volt of input change. Fortunately, the input thermal tends to cancel the output thermal. For this reason the noninverting gain of two configurations settles faster than the inverting gain of one. LT1229/LT1230 U W U UO APPLICATI S I FOR ATIO Crosstalk and Cascaded Amplifiers The amplifiers in the LT1229/LT1230 do not share any common circuitry. The only thing the amplifiers share is the supplies. As a result, the crosstalk between amplifiers is very low. In a good breadboard or with a good PC board layout the crosstalk from the output of one amplifier to the input of another will be over 100dB down, up to 100kHz and 65dB down at 10MHz. The following curve shows the crosstalk from the output of one amplifier to the input of another. Amplifier Crosstalk vs Frequency OUTPUT TO INPUT CROSSTALK (dB) 120 VS = 15V AV = 10 RS = 50 RL = 100 110 100 90 80 70 60 50 10 100 1k 10k 100k 1M 10M 100M FREQUENCY (Hz) LT1229 * TA12 The high frequency crosstalk between amplifiers is caused by magnetic coupling between the internal wire bonds that connect the IC chip to the package lead frame. The amount of crosstalk is inversely proportional to the load resistor the amplifier is driving, with no load (just the feedback resistor) the crosstalk improves 18dB. The curve shows the crosstalk of the LT1229 amplifier B output (Pin 7) to the input of amplifier A. The crosstalk from amplifier A's output (Pin 1) to amplifier B is about 10dB better. The crosstalk between all of the LT1230 amplifiers is as shown. The LT1230 amplifiers that are separated by the supplies are a few dB better. When cascading amplifiers the crosstalk will limit the amount of high frequency gain that is available because the crosstalk signal is out of phase with the input signal. This will often show up as unusual frequency response. For example: cascading the two amplifiers in the LT1229, each set up with 20dB of gain and a -3dB bandwidth of 65MHz into 100 will result in 40dB of gain, BUT the response will start to drop at about 10MHz and then flatten out from 20MHz to 30MHz at about 0.5dB down. This is due to the crosstalk back to the input of the first amplifier. For best results when cascading amplifiers use the LT1229 and drive amplifier B and follow it with amplifier A. UO S Single 5V Supply Cable Driver for Composite Video The transistor's base is biased by R1 and R2 at 2V. The emitter of the transistor clamps the noninverting input of the amplifier to 1.4V at the most negative part of the input 5V R1 3k R4 1.5k C3 47F 2N3904 R2 2k C2 1F C1 1F + This circuit amplifies standard 1V peak composite video input (1.4VP-P) by two and drives an AC coupled, doubly terminated cable. In order for the output to swing 2.8VP-P on a single 5V supply, it must be biased accurately. The average DC level of the composite input is a function of the luminance signal. This will cause problems if we AC couple the input signal into the amplifier because a rapid change in luminance will drive the output into the rails. To prevent this we must establish the DC level at the input and operate the amplifier with DC gain. (the sync pulses). R4, R5 and R6 set the amplifier up with a gain of two and bias the output so the bottom of the sync pulses are at 1.1V. The maximum input then drives the output to 3.9V. + VIN 1/2 LT1229 R3 150k - R5 750 C4 1000F + TYPICAL APPLICATI R6 510 R7 75 VOUT R8 10k LT1229 * TA11 11 LT1229/LT1230 U PACKAGE DESCRIPTIO J8 Package 8-Lead CERDIP (Narrow .300 Inch, Hermetic) (Reference LTC DWG # 05-08-1110) CORNER LEADS OPTION (4 PLCS) 0.005 (0.127) MIN 0.023 - 0.045 (0.584 - 1.143) HALF LEAD OPTION 0.045 - 0.068 (1.143 - 1.727) FULL LEAD OPTION 0.405 (10.287) MAX 8 7 6 5 0.025 (0.635) RAD TYP 0.220 - 0.310 (5.588 - 7.874) 1 2 3 0.300 BSC (0.762 BSC) 4 0.200 (5.080) MAX 0.015 - 0.060 (0.381 - 1.524) 0.008 - 0.018 (0.203 - 0.457) 0 - 15 0.045 - 0.065 (1.143 - 1.651) NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE OR TIN PLATE LEADS 0.014 - 0.026 (0.360 - 0.660) 0.125 3.175 MIN 0.100 (2.54) BSC J8 1298 J Package 14-Lead CERDIP (Narrow .300 Inch, Hermetic) (Reference LTC DWG # 05-08-1110) 0.005 (0.127) MIN 0.785 (19.939) MAX 14 13 12 11 10 9 8 0.220 - 0.310 (5.588 - 7.874) 0.025 (0.635) RAD TYP 1 2 3 4 5 6 7 0.300 BSC (0.762 BSC) 0.200 (5.080) MAX 0.015 - 0.060 (0.381 - 1.524) 0.008 - 0.018 (0.203 - 0.457) 0 - 15 0.045 - 0.065 (1.143 - 1.651) NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE OR TIN PLATE LEADS 0.014 - 0.026 (0.360 - 0.660) OBSOLETE PACKAGES 12 0.100 (2.54) BSC 0.125 (3.175) MIN J14 1298 LT1229/LT1230 U PACKAGE DESCRIPTIO N8 Package 8-Lead PDIP (Narrow .300 Inch) (Reference LTC DWG # 05-08-1510) 0.400* (10.160) MAX 8 7 6 5 1 2 3 4 0.255 0.015* (6.477 0.381) 0.300 - 0.325 (7.620 - 8.255) 0.009 - 0.015 (0.229 - 0.381) ( 0.065 (1.651) TYP +0.035 0.325 -0.015 8.255 +0.889 -0.381 0.130 0.005 (3.302 0.127) 0.045 - 0.065 (1.143 - 1.651) ) 0.125 (3.175) 0.020 MIN (0.508) MIN 0.018 0.003 (0.457 0.076) 0.100 (2.54) BSC N8 1098 *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610) 0.189 - 0.197* (4.801 - 5.004) 8 7 6 5 0.150 - 0.157** (3.810 - 3.988) 0.228 - 0.244 (5.791 - 6.197) SO8 1298 1 0.010 - 0.020 x 45 (0.254 - 0.508) 0.008 - 0.010 (0.203 - 0.254) 0.053 - 0.069 (1.346 - 1.752) 0- 8 TYP 0.016 - 0.050 (0.406 - 1.270) 0.014 - 0.019 (0.355 - 0.483) TYP *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 2 3 4 0.004 - 0.010 (0.101 - 0.254) 0.050 (1.270) BSC 13 LT1229/LT1230 U PACKAGE DESCRIPTIO S Package 14-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610) 0.337 - 0.344* (8.560 - 8.738) 14 13 12 11 10 9 8 0.228 - 0.244 (5.791 - 6.197) 0.150 - 0.157** (3.810 - 3.988) 1 0.010 - 0.020 x 45 (0.254 - 0.508) 0.008 - 0.010 (0.203 - 0.254) 3 4 5 0.053 - 0.069 (1.346 - 1.752) 0.014 - 0.019 (0.355 - 0.483) TYP *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 6 7 0.004 - 0.010 (0.101 - 0.254) 0 - 8 TYP 0.016 - 0.050 (0.406 - 1.270) 14 2 0.050 (1.270) BSC S14 1298 LT1229/LT1230 U PACKAGE DESCRIPTIO N Package 14-Lead PDIP (Narrow .300 Inch) (Reference LTC DWG # 05-08-1510) 0.770* (19.558) MAX 14 13 12 11 10 9 8 1 2 3 4 5 6 7 0.255 0.015* (6.477 0.381) 0.130 0.005 (3.302 0.127) 0.300 - 0.325 (7.620 - 8.255) 0.045 - 0.065 (1.143 - 1.651) 0.020 (0.508) MIN 0.065 (1.651) TYP 0.009 - 0.015 (0.229 - 0.381) +0.035 0.325 -0.015 0.005 (0.125) MIN 0.100 (2.54) *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. BSC MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) ( +0.889 8.255 -0.381 ) 0.125 (3.175) MIN Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 0.018 0.003 (0.457 0.076) N14 1098 15 LT1229/LT1230 UO TYPICAL APPLICATI S Single Supply AC Coupled Amplifiers Noninverting 5V 0.1F Inverting +4.7F 5V 10k 10k + VIN 10k 1/2 LT1229 + VOUT 0.1F - 4.7F + 51 +4.7F 1/2 LT1229 VOUT - 510 RS VIN LT1229 * TA09 4.7F + AV = 11 BW = 600Hz TO 50MHz 10k 51 510 510 AV = 10 RS + 51 BW = 600Hz TO 50MHz LT1229 * TA10 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1227 Single 140MHz CFA Single Version of the LT1229 LT1395/LT1396/LT1397 Single/Dual/Quad 400MHz CFA 16 Linear Technology Corporation SOT-23, MSOP-8 and SSOP-16 Packaging 122930fb LT/CP 0801 1.5K REV B * PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 www.linear.com LINEAR TECHNOLOGY CORPORATION 1992