LT1206CR

LT1206 250mA/60MHz Current Feedback Amplifier FEATURES s s s s s s s s s s DESCRIPTIO 250mA Minimum Output Drive Current 60MHz Bandwidth, AV = 2, RL = 100Ω 900V/µs Slew Rate, AV = 2, RL = 50Ω 0.02% Differential Gain, AV = 2, RL = 30Ω 0.17° Differential Phase, AV = 2, RL = 30Ω High Input Impedance, 10MΩ Wide Supply Range, ± 5V to ± 15V Shutdown Mode: IS < 200µA Adjustable Supply Current Stable with CL = 10,000pF APPLICATIO S s s s s s The LT1206 is a current feedback amplifier with high output current drive capability and excellent video characteristics. The LT1206 is stable with large capacitive loads, and can easily supply the large currents required by the capacitive loading. A shutdown feature switches the device into a high impedance, low current mode, reducing dissipation when the device is not in use. For lower bandwidth applications, the supply current can be reduced with a single external resistor. The low differential gain and phase, wide bandwidth, and the 250mA minimum output current drive make the LT1206 well suited to drive multiple cables in video systems. The LT1206 is manufactured on Linear Technology’s proprietary complementary bipolar process. Video Amplifiers Cable Drivers RGB Amplifiers Test Equipment Amplifiers Buffers TYPICAL APPLICATIO S Noninverting Amplifier with Shutdown 15V VIN Large-Signal Response, CL = 10,000pF + LT1206 COMP CCOMP – S/D** 0.01µF* –15V RF 15V 5V RG 24k 74C906 LT1206 • TA01 VOUT *OPTIONAL, USE WITH CAPACITIVE LOADS **GROUND SHUTDOWN PIN FOR NORMAL OPERATION VS = ±15V RL = ∞ RF = RG = 3k ENABLE LT1206 • TA02 U U U 1 LT1206 ABSOLUTE AXI U RATI GS Operating Temperature Range LT1206C ........................................... – 40°C to 85°C Junction Temperature ......................................... 150°C Storage Temperature Range ................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec)................. 300°C Supply Voltage ..................................................... ± 18V Input Current .................................................... ± 15mA Output Short-Circuit Duration (Note 1) ....... Continuous Specified Temperature Range (Note 2) ...... 0°C to 70°C PACKAGE/ORDER I FOR ATIO TOP VIEW NC 1 –IN 2 +IN 3 S/D* 4 8 7 6 5 V + ORDER PART NUMBER LT1206CN8** OUT V– COMP N8 PACKAGE 8-LEAD PLASTIC DIP θJA = 100°C/W FRONT VIEW 7 6 5 4 3 2 1 OUT V– COMP V+ S/D* +IN –IN ORDER PART NUMBER LT1206CR** TAB IS V+ TAB IS V+ R PACKAGE 7-LEAD PLASTIC DD θJA ≈ 30°C/W *Ground shutdown pin for normal operation **See Note 2 ELECTRICAL CHARACTERISTICS VCM = 0, ± 5V ≤ VS ≤ ± 15V, pulse tested, VS/D = 0V, unless otherwise noted. SYMBOL VOS PARAMETER Input Offset Voltage Input Offset Voltage Drift IIN + CONDITIONS TA = 25°C q q Noninverting Input Current Inverting Input Current Input Noise Voltage Density Input Noise Current Density Input Noise Current Density Input Resistance Input Capacitance Input Voltage Range TA = 25°C q IIN– en +in –in RIN CIN TA = 25°C q f = 10kHz, RF = 1k, RG = 10Ω, RS = 0Ω f = 10kHz, RF = 1k, RG = 10Ω, RS = 10k f = 10kHz, RF = 1k, RG = 10Ω, RS = 10k VIN = ± 12V, VS = ± 15V VIN = ± 2V, VS = ± 5V VS = ± 15V VS = ± 15V VS = ± 5V q q q q 2 U U W WW U W TOP VIEW V+ 1 –IN 2 +IN 3 S/D* 4 8 7 6 5 V+ OUT V– COMP ORDER PART NUMBER LT1206CS8** PART MARKING 1206 ORDER PART NUMBER LT1206CY** S8 PACKAGE 8-LEAD PLASTIC SO θJA ≈ 60°C/W FRONT VIEW 7 6 5 4 3 2 1 Y PACKAGE 7-LEAD TO-220 OUT V– COMP V+ S/D* +IN –IN θJC = 5°C/W MIN TYP ±3 10 ±2 ±10 3.6 2 30 MAX ±10 ±15 ±5 ± 20 ± 60 ±100 UNITS mV mV µV/°C µA µA µA µA nV/√Hz pA/√Hz pA/√Hz MΩ MΩ pF V V 1.5 0.5 ±12 ±2 10 5 2 ±13.5 ± 3.5 LT1206 ELECTRICAL CHARACTERISTICS VCM = 0, ± 5V ≤ VS ≤ ± 15V, pulse tested, VS/D = 0V, unless otherwise noted. SYMBOL CMRR PARAMETER Common-Mode Rejection Ratio Inverting Input Current Common-Mode Rejection PSRR Power Supply Rejection Ratio Noninverting Input Current Power Supply Rejection Inverting Input Current Power Supply Rejection AV ROL VOUT Large-Signal Voltage Gain Transresistance, ∆VOUT/∆IIN– Maximum Output Voltage Swing CONDITIONS VS = ± 15V, VCM = ± 12V VS = ± 5V, VCM = ± 2V VS = ± 15V, VCM = ± 12V VS = ± 5V, VCM = ± 2V VS = ± 5V to ± 15V VS = ± 5V to ± 15V VS = ± 5V to ± 15V VS = ± 15V, VOUT = ± 10V, RL = 50Ω VS = ± 5V, VOUT = ± 2V, RL = 25Ω VS = ± 15V, VOUT = ± 10V, RL = 50Ω VS = ± 5V, VOUT = ± 2V, RL = 25Ω VS = ± 15V, RL = 50Ω, TA = 25°C VS = ± 5V, RL = 25Ω, TA = 25°C IOUT IS Maximum Output Current Supply Current Supply Current, RS/D = 51k (Note 3) Positive Supply Current, Shutdown Output Leakage Current, Shutdown SR Slew Rate (Note 4) Differential Gain (Note 5) Differential Phase (Note 5) BW Small-Signal Bandwidth RL = 1Ω VS = ± 15V, VS/D = 0V, TA = 25°C q q q q q q q q q q q q q q q MIN 55 50 TYP 62 60 0.1 0.1 MAX UNITS dB dB 10 10 500 5 µA/V µA/V dB nA/V µA/V dB dB kΩ kΩ V V V V 60 77 30 0.7 55 55 100 75 ± 11.5 ± 10.0 ± 2.5 ± 2.0 250 71 68 260 200 ± 12.5 ± 3.0 500 20 12 1200 30 35 17 200 10 mA mA mA mA µA µA V/µs % DEG MHz MHz MHz MHz VS = ± 15V, TA = 25°C VS = ± 15V, VS/D = 15V VS = ± 15V, VS/D = 15V AV = 2, TA = 25°C VS = ± 15V, RF = 560Ω, RG = 560Ω, RL = 30Ω VS = ± 15V, RF = 560Ω, RG = 560Ω, RL = 30Ω VS = ± 15V, Peaking ≤ 0.5dB RF = RG = 620Ω, RL = 100Ω VS = ± 15V, Peaking ≤ 0.5dB RF = RG = 649Ω, RL = 50Ω VS = ± 15V, Peaking ≤ 0.5dB RF = RG = 698Ω, RL = 30Ω VS = ± 15V, Peaking ≤ 0.5dB RF = RG = 825Ω, RL = 10Ω q q 400 900 0.02 0.17 60 52 43 27 The q denotes specifications which apply for 0°C ≤ TA ≤ 70°C. Note 1: Applies to short circuits to ground only. A short circuit between the output and either supply may permanently damage the part when operated on supplies greater than ± 10V. Note 2: Commercial grade parts are designed to operate over the temperature range of – 40°C to 85°C but are neither tested nor guaranteed beyond 0°C to 70°C. Industrial grade parts tested over – 40°C to 85°C are available on special request. Consult factory. Note 3: RS/D is connected between the shutdown pin and ground. Note 4: Slew rate is measured at ± 5V on a ± 10V output signal while operating on ± 15V supplies with RF = 1.5k, RG = 1.5k and RL = 400Ω. Note 5: NTSC composite video with an output level of 2V. 3 LT1206 S ALL-SIG AL BA DWIDTH IS = 20mA Typical, Peaking ≤ 0.1dB AV RL RF 562 649 732 619 715 806 576 649 750 442 511 649 RG 562 649 732 – – – 576 649 750 48.7 56.2 71.5 – 3dB BW (MHz) 48 34 22 54 36 22.4 48 35 22.4 40 31 20 – 0.1dB BW (MHz) 21.4 17 12.5 22.3 17.5 11.5 20.7 18.1 11.7 19.2 16.5 10.2 AV RL RF 681 768 887 768 909 1k 665 787 931 487 590 768 RG 681 768 887 – – – 665 787 931 536 64.9 84.5 – 3dB BW (MHz) 50 35 24 66 37 23 55 36 22.5 44 33 20.7 – 0.1dB BW (MHz) 19.2 17 12.3 22.4 17.5 12 23 18.5 11.8 20.7 17.5 10.8 VS = ±5V, RSD = 0Ω –1 150 30 10 1 150 30 10 2 150 30 10 10 150 30 10 IS = 10mA Typical, Peaking ≤ 0.1dB AV RL RF RG 576 681 750 – – – 590 681 768 33.2 43.2 54.9 – 3dB BW (MHz) 35 25 16.4 37 25 16.5 35 25 16.2 31 23 15 – 0.1dB BW (MHz) 17 12.5 8.7 17.5 12.6 8.2 16.8 13.4 8.1 15.6 11.9 7.8 AV RL RF RG 634 768 866 – – – 649 787 931 33.2 44.2 64.9 – 3dB BW (MHz) 41 26.5 17 44 28 16.8 40 27 16.5 33 25 15.3 – 0.1dB BW (MHz) 19.1 14 9.4 18.8 14.4 8.3 18.5 14.1 8.1 15.6 13.3 7.4 VS = ±5V, RSD = 10.2k –1 150 576 30 681 10 750 1 150 665 30 768 10 845 2 150 590 30 681 10 768 10 150 301 30 392 10 499 IS = 5mA Typical, Peaking ≤ 0.1dB AV –1 RL 150 30 10 150 30 10 150 30 10 150 30 10 RF 604 715 681 768 866 825 634 750 732 100 100 100 RG 604 715 681 – – – 634 750 732 11.1 11.1 11.1 – 3dB BW (MHz) 21 14.6 10.5 20 14.1 9.8 20 14.1 9.6 16.2 13.4 9.5 – 0.1dB BW (MHz) 10.5 7.4 6.0 9.6 6.7 5.1 9.6 7.2 5.1 5.8 7.0 4.7 AV –1 RL 150 30 10 150 30 10 150 30 10 150 30 10 RF 619 787 825 845 1k 1k 681 845 866 100 100 100 RG 619 787 825 – – – 681 845 866 11.1 11.1 11.1 – 3dB BW (MHz) 25 15.8 10.5 23 15.3 10 23 15 10 15.9 13.6 9.6 – 0.1dB BW (MHz) 12.5 8.5 5.4 10.6 7.6 5.2 10.2 7.7 5.4 4.5 6 4.5 VS = ±5V, RSD = 22.1k 1 2 10 4 U U W VS = ±5V, RSD = 0Ω –1 150 30 10 1 150 30 10 2 150 30 10 10 150 30 10 VS = ±15V, RSD = 60.4k –1 150 634 30 768 10 866 1 150 768 30 909 10 1k 2 150 649 30 787 10 931 10 150 301 30 402 10 590 VS = ±15V, RSD = 121k 1 2 10 LT1206 TYPICAL PERFOR A CE CHARACTERISTICS Bandwidth vs Supply Voltage 100 90 – 3dB BANDWIDTH (MHz) PEAKING ≤ 0.5dB PEAKING ≤ 5dB RF = 470Ω RF = 560Ω AV = 2 RL = 100Ω FEEDBACK RESISTOR (Ω) 70 60 50 40 30 20 10 0 4 –3dB BANDWIDTH (MHz) 80 RF = 680Ω RF = 750Ω RF = 1k RF = 1.5k 6 14 12 10 8 SUPPLY VOLTAGE (±V) LT1206 • TPC01 Bandwidth vs Supply Voltage 100 90 PEAKING ≤ 0.5dB PEAKING ≤ 5dB AV = 10 RL = 100Ω – 3dB BANDWIDTH (MHz) FEEDBACK RESISTOR (Ω) –3dB BANDWIDTH (MHz) 80 70 60 50 40 30 20 10 0 4 6 14 12 10 8 SUPPLY VOLTAGE (±V) 16 18 RF = 470Ω RF = 680Ω RF = 1.5k RF =390Ω RF = 330Ω LT1206 • TPC04 Differential Phase vs Supply Voltage 0.50 RL = 15Ω 0.10 DIFFERENTIAL PHASE (DEG) 0.40 0.08 RL = 15Ω SPOT NOISE (nV/√Hz OR pA/√Hz) 0.30 DIFFERENTIAL GAIN (%) 0.20 RF = RG = 560Ω AV = 2 N PACKAGE RL = 30Ω RL = 50Ω RL = 150Ω 0.10 0 5 7 11 13 9 SUPPLY VOLTAGE (±V) 15 LT1206 • TPC07 UW 16 18 Bandwidth vs Supply Voltage 50 PEAKING ≤ 0.5dB PEAKING ≤ 5dB 40 RF = 560Ω RF = 750Ω RF = 1k RF = 2k 10 AV = 2 RL = 10Ω Bandwidth and Feedback Resistance vs Capacitive Load for 0.5dB Peak 10k BANDWIDTH –3dB BANDWIDTH (MHz) 100 30 1k FEEDBACK RESISTOR AV = 2 RL = ∞ VS = ± 15V CCOMP = 0.01µF 1 100 10 1000 CAPACITIVE LOAD (pF) 10 20 0 4 6 14 12 10 8 SUPPLY VOLTAGE (±V) 16 18 100 1 10000 LT1206 • TPC03 LT1206 • TPC02 Bandwidth vs Supply Voltage 50 PEAKING ≤ 0.5dB PEAKING ≤ 5dB 40 RF = 560Ω RF = 680Ω RF = 1k 10 RF = 1.5k 0 100 4 6 14 12 10 8 SUPPLY VOLTAGE (±V) 16 18 AV = 10 RL = 10Ω 10k Bandwidth and Feedback Resistance vs Capacitive Load for 5dB Peak 100 BANDWIDTH –3dB BANDWIDTH (MHz) 30 1k 10 20 FEEDBACK RESISTOR 0 AV = +2 RL = ∞ VS = ±15V CCOMP = 0.01µF 1 10 100 1k CAPACITIVE LOAD (pF) 1 10k LT1206 • TPC05 LT1206 • TPC06 Differential Gain vs Supply Voltage 100 RF = RG = 560Ω AV = 2 N PACKAGE Spot Noise Voltage and Current vs Frequency –in 0.06 RL = 30Ω 0.04 RL = 50Ω 10 en in 1 10 0.02 RL = 150Ω 0 5 7 11 13 9 SUPPLY VOLTAGE (±V) 15 100 1k 10k FREQUENCY (Hz) 100k LT1206 • TPC09 LT1206 • TPC08 5 LT1206 TYPICAL PERFOR A CE CHARACTERISTICS Supply Current vs Supply Voltage 24 VS/D = 0V 22 SUPPLY CURRENT (mA) TJ = – 40˚C 20 TJ = 25˚C 18 16 14 TJ = 125˚C 12 10 4 6 14 12 10 8 SUPPLY VOLTAGE (±V) 16 18 TJ = 85˚C SUPPLY CURRENT (mA) SUPPLY CURRENT (mA) LT1206 • TPC10 Supply Current vs Shutdown Pin Current 20 18 16 VS = ±15V – 0.5 COMMON-MODE RANGE (V) OUTPUT SHORT-CIRCUIT CURRENT (A) SUPPLY CURRENT (mA) 14 12 10 8 6 4 2 0 0 100 300 400 200 SHUTDOWN PIN CURRENT (µA) 500 Output Saturation Voltage vs Junction Temperature V+ OUTPUT SATURATION VOLTAGE (V) POWER SUPPLY REJECTION (dB) –1 –2 –3 –4 4 3 2 1 VS = ±15V RL = 2k 50 40 30 20 10 0 10k POSITIVE SUPPLY CURRENT (mA) RL = 50Ω RL = 50Ω RL = 2k V– –50 –25 0 25 50 75 TEMPERATURE (°C) LT1206 • TPC16 6 UW LT1206 • TPC11 Supply Current vs Ambient Temperature, VS = ± 5V 25 RSD = 0Ω AV = 1 RL = ∞ N PACKAGE 25 Supply Current vs Ambient Temperature, VS = ± 15V RSD = 0Ω 20 AV = 1 RL = ∞ N PACKAGE 20 15 RSD = 10.2k 10 RSD = 22.1k 15 RSD = 60.4k 10 RSD = 121k 5 5 0 –50 –25 50 25 0 75 TEMPERATURE (°C) 100 125 0 –50 –25 50 25 0 75 TEMPERATURE (°C) 100 125 LT1206 • TPC11 LT1206 • TPC12 Input Common-Mode Limit vs Junction Temperature V+ 1.0 0.9 0.8 Output Short-Circuit Current vs Junction Temperature –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 V– –50 –25 0 25 50 75 TEMPERATURE (°C) 100 125 SOURCING 0.7 0.6 SINKING 0.5 0.4 0.3 –50 –25 50 25 75 0 TEMPERATURE (°C) 100 125 LT1206 • TPC14 LT1206 • TPC15 Power Supply Rejection Ratio vs Frequency 70 60 NEGATIVE RL = 50Ω VS = ± 15V RF = RG = 1k Supply Current vs Large Signal Output Frequency (No Load) 60 AV = 2 RL = ∞ VS = ± 15V VOUT = 20VP-P 50 40 30 20 100 125 100k 1M 10M FREQUENCY (Hz) 100M LT1206 • TPC17 10 10k 100k 1M 10M LT1206 • TPC18 FREQUENCY (Hz) LT1206 TYPICAL PERFOR A CE CHARACTERISTICS Output Impedance vs Frequency 100 VS = ±15V IO = 0mA OUTPUT IMPEDANCE (Ω) OUTPUT IMPEDANCE (Ω) 10 RS/D = 121k DISTORTION (dBc) 1 RS/D = 0Ω 0.1 0.01 100k 1M 10M FREQUENCY (Hz) LT1206 • TPC19 3rd Order Intercept vs Frequency 60 VS = ± 15V RL = 50Ω RF = 590Ω RG = 64.9Ω 3rd ORDER INTERCEPT (dBm) 50 40 30 20 10 0 5 UW 100M Output Impedance in Shutdown vs Frequency 100k AV = 1 RF = 1k VS = ± 15V 10k –50 –60 –70 –80 –30 –40 2nd and 3rd Harmonic Distortion vs Frequency VS = ±15V VO = 2VP-P RL = 10Ω 2nd 3rd 2nd 1k RL = 30Ω 100 3rd 10 100k –90 1M 10M 100M LT1206 • TPC20 1 FREQUENCY (Hz) 2 45 3 FREQUENCY (MHz) 6 7 8 9 10 LT1206 • TPC21 Test Circuit for 3rd Order Intercept + LT1206 PO – 590Ω 65Ω MEASURE INTERCEPT AT PO LT1206 • TPC23 50Ω 10 15 20 FREQUENCY (MHz) 25 30 LT1206 • TPC22 7 LT1206 SI PLIFIED SCHE ATIC V+ TO ALL CURRENT SOURCES Q2 Q18 Q17 1.25k +IN –IN CC Q1 Q6 Q9 V– RC 50Ω COMP OUTPUT V+ V+ Q12 Q8 Q4 Q7 D2 Q13 Q16 Q14 APPLICATI S I FOR ATIO The LT1206 is a current feedback amplifier with high output current drive capability. The device is stable with large capacitive loads and can easily supply the high currents required by capacitive loads. The amplifier will drive low impedance loads such as cables with excellent linearity at high frequencies. Feedback Resistor Selection The optimum value for the feedback resistors is a function of the operating conditions of the device, the load impedance and the desired flatness of response. The Typical AC Performance tables give the values which result in the highest 0.1dB and 0.5dB bandwidths for various resistive loads and operating conditions. If this level of flatness is not required, a higher bandwidth can be obtained by use of a lower feedback resistor. The characteristic curves of Bandwidth vs Supply Voltage indicate feedback resistors for peaking up to 5dB. These curves use a solid line when the response has less than 0.5dB of peaking and a dashed 8 U W W U UO W Q5 D1 Q15 Q10 Q11 V– SHUTDOWN Q3 V– LT1206 • TC line when the response has 0.5dB to 5dB of peaking. The curves stop where the response has more than 5dB of peaking. For resistive loads, the COMP pin should be left open (see section on capacitive loads). Capacitive Loads The LT1206 includes an optional compensation network for driving capacitive loads. This network eliminates most of the output stage peaking associated with capacitive loads, allowing the frequency response to be flattened. Figure 1 shows the effect of the network on a 200pF load. Without the optional compensation, there is a 5dB peak at 40MHz caused by the effect of the capacitance on the output stage. Adding a 0.01µF bypass capacitor between the output and the COMP pins connects the compensation and completely eliminates the peaking. A lower value feedback resistor can now be used, resulting in a response LT1206 APPLICATI 12 10 8 VOLTAGE GAIN (dB) S I FOR ATIO VS = ±15V RF = 1.2k COMPENSATION 6 4 2 0 –2 –4 –6 –8 1 RF = 2k NO COMPENSATION RF = 2k COMPENSATION 10 FREQUENCY (MHz) 100 LT1206 • F01 Figure 1. which is flat to 0.35dB to 30MHz. The network has the greatest effect for CL in the range of 0pF to 1000pF. The graph of Maximum Capacitive Load vs Feedback Resistor can be used to select the appropriate value of feedback resistor. The values shown are for 0.5dB and 5dB peaking at a gain of 2 with no resistive load. This is a worst case condition, as the amplifier is more stable at higher gains and with some resistive load in parallel with the capacitance. Also shown is the – 3dB bandwidth with the suggested feedback resistor vs the load capacitance. Although the optional compensation works well with capacitive loads, it simply reduces the bandwidth when it is connected with resistive loads. For instance, with a 30Ω load, the bandwidth drops from 55MHz to 35MHz when the compensation is connected. Hence, the compensation was made optional. To disconnect the optional compensation, leave the COMP pin open. Shutdown/Current Set If the shutdown feature is not used, the SHUTDOWN pin must be connected to ground or V –. The shutdown pin can be used to either turn off the biasing for the amplifier, reducing the quiescent current to less than 200µA, or to control the quiescent current in normal operation. The total bias current in the LT1206 is controlled by the current flowing out of the shutdown pin. When the shutdown pin is open or driven to the positive supply, the part is shut down. In the shutdown mode, the output looks like ENABLE VOUT U a 40pF capacitor and the supply current is typically 100µA. The shutdown pin is referenced to the positive supply through an internal bias circuit (see the simplified schematic). An easy way to force shutdown is to use open drain (collector) logic. The circuit shown in Figure 2 uses a 74C904 buffer to interface between 5V logic and the LT1206. The switching time between the active and shutdown states is less than 1µs. A 24k pull-up resistor speeds up the turn-off time and insures that the LT1206 is completely turned off. Because the pin is referenced to the positive supply, the logic used should have a breakdown voltage of greater than the positive supply voltage. No other circuitry is necessary as the internal circuit limits the shutdown pin current to about 500µA. Figure 3 shows the resulting waveforms. 15V VIN W U UO + LT1206 VOUT – S/D –15V RF 15V 5V ENABLE 74C906 24k RG LT1206 • F02 Figure 2. Shutdown Interface AV = 1 RF = 825Ω RL = 50Ω RPU = 24k VIN = 1VP-P LT1206 • F3 Figure 3. Shutdown Operation 9 LT1206 APPLICATI S I FOR ATIO U Slew Rate Unlike a traditional op amp, the slew rate of a current feedback amplifier is not independent of the amplifier gain configuration. There are slew rate limitations in both the input stage and the output stage. In the inverting mode, and for higher gains in the noninverting mode, the signal amplitude on the input pins is small and the overall slew rate is that of the output stage. The input stage slew rate is related to the quiescent current and will be reduced as the supply current is reduced. The output slew rate is set by the value of the feedback resistors and the internal capacitance. Larger feedback resistors will reduce the slew rate as will lower supply voltages, similar to the way the bandwidth is reduced. The photos (Figures 5a, 5b and 5c) show the large-signal response of the LT1206 for various gain configurations. The slew rate varies from 860V/µs for a gain of 1, to 1400V/µs for a gain of – 1. RF = 825Ω RL = 50Ω VS = ±15V LT1206 • F05a For applications where the full bandwidth of the amplifier is not required, the quiescent current of the device may be reduced by connecting a resistor from the shutdown pin to ground. The quiescent current will be approximately 40 times the current in the shutdown pin. The voltage across the resistor in this condition is V + – 3VBE. For example, a 60k resistor will set the quiescent supply current to 10mA with VS = ±15V. The photos (Figures 4a and 4b) show the effect of reducing the quiescent supply current on the large-signal response. The quiescent current can be reduced to 5mA in the inverting configuration without much change in response. In noninverting mode, however, the slew rate is reduced as the quiescent current is reduced. RF = 750Ω RL = 50Ω IQ = 5mA, 10mA, 20mA VS = ±15V Figure 4a. Large-Signal Response vs IQ, AV = – 1 RF = 750Ω RL = 50Ω IQ = 5mA, 10mA, 20mA VS = ±15V Figure 4b. Large-Signal Response vs IQ, AV = 2 RF = RG = 750Ω RL = 50Ω VS = ±15V LT1206 • F05b 10 W U UO LT1206 • F04a Figure 5a. Large-Signal Response, AV = 1 LT1206 • F04b Figure 5b. Large-Signal Response, AV = – 1 LT1206 APPLICATI S I FOR ATIO U the maximum allowable input voltage. To allow for some margin, it is recommended that the input signal be less than ± 5V when the device is shut down. Capacitance on the Inverting Input Current feedback amplifiers require 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. Power Supplies When the LT1206 is used to drive capacitive loads, the available output current can limit the overall slew rate. In the fastest configuration, the LT1206 is capable of a slew rate of over 1V/ns. The current required to slew a capacitor at this rate is 1mA per picofarad of capacitance, so 10,000pF would require 10A! The photo (Figure 6) shows the large signal behavior with CL = 10,000pF. The slew rate is about 60V/µs, determined by the current limit of 600mA. The LT1206 will operate from single or split supplies from ± 5V (10V 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 500µV per volt of supply mismatch. The inverting bias current can change as much as 5µA per volt of supply mismatch, though typically the change is less than 0.5µA per volt. Thermal Considerations The LT1206 contains a thermal shutdown feature which protects against excessive internal (junction) temperature. If the junction temperature of the device exceeds the protection threshold, the device will begin cycling between normal operation and an off state. The cycling is not harmful to the part. The thermal cycling occurs at a slow rate, typically 10ms to several seconds, which depends on the power dissipation and the thermal time constants of the package and heat sinking. Raising the ambient temperature until the device begins thermal shutdown gives a good indication of how much margin there is in the thermal design. For surface mount devices heat sinking is accomplished by using the heat spreading capabilities of the PC board and its copper traces. Experiments have shown that the heat spreading copper layer does not need to be electrically connected to the tab of the device. The PCB material can be very effective at transmitting heat between the pad area attached to the tab of the device, and a ground or RF = 750Ω RL = 50Ω Figure 5c. Large-Signal Response, AV = 2 VS = ±15V RF = RG = 3k RL = ∞ Figure 6. Large-Signal Response, CL = 10,000pF Differential Input Signal Swing The differential input swing is limited to about ± 6V by an ESD protection device connected between the inputs. In normal operation, the differential voltage between the input pins is small, so this clamp has no effect; however, in the shutdown mode the differential swing can be the same as the input swing. The clamp voltage will then set W U UO LT1206 • F04c LT1206 • F06 11 LT1206 APPLICATI S I FOR ATIO U Calculating Junction Temperature The junction temperature can be calculated from the equation: TJ = (PD × θJA) + TA where: TJ = Junction Temperature TA = Ambient Temperature PD = Device Dissipation θJA = Thermal Resistance (Junction-to Ambient) As an example, calculate the junction temperature for the circuit in Figure 7 for the N8, S8, and R packages assuming a 70°C ambient temperature. 15V I 39mA power plane layer either inside or on the opposite side of the board. Although the actual thermal resistance of the PCB material is high, the length/area ratio of the thermal resistance between the layer is small. Copper board stiffeners and plated through holes can also be used to spread the heat generated by the device. Tables 1 and 2 list thermal resistance for each package. For the TO-220 package, thermal resistance is given for junction-to-case only since this package is usually mounted to a heat sink. Measured values of thermal resistance for several different board sizes and copper areas are listed for each surface mount package. All measurements were taken in still air on 3/32" FR-4 board with 1oz copper. This data can be used as a rough guideline in estimating thermal resistance. The thermal resistance for each application will be affected by thermal interactions with other components as well as board size and shape. Table 1. R Package, 7-Lead DD COPPER AREA TOPSIDE* BACKSIDE 2500 sq. mm 2500 sq. mm 1000 sq. mm 2500 sq. mm 125 sq. mm 2500 sq. mm THERMAL RESISTANCE BOARD AREA (JUNCTION-TO-AMBIENT) 2500 sq. mm 2500 sq. mm 2500 sq. mm 25°C/W 27°C/W 35°C/W *Tab of device attached to topside copper Table 2. S8 Package, 8-Lead Plastic SOIC COPPER AREA TOPSIDE* 2500 sq. mm 1000 sq. mm 225 sq. mm 100 sq. mm 100 sq. mm 100 sq. mm 100 sq. mm BACKSIDE 2500 sq. mm 2500 sq. mm 2500 sq. mm 2500 sq. mm 1000 sq. mm 225 sq. mm 100 sq. mm THERMAL RESISTANCE BOARD AREA (JUNCTION-TO-AMBIENT) 2500 sq. mm 2500 sq. mm 2500 sq. mm 2500 sq. mm 2500 sq. mm 2500 sq. mm 2500 sq. mm 60°C/W 62°C/W 65°C/W 69°C/W 73°C/W 80°C/W 83°C/W *Pins 1 and 8 attached to topside copper Y Package, 7-Lead TO-220 Thermal Resistance (Junction-to-Case) = 5°C/W N8 Package, 8-Lead DIP Thermal Resistance (Junction-to-Ambient) = 100°C/W 12 W U UO + 330Ω 12V 0.01µF 2k 300pF f = 2MHz –12V – LT1206 S/D –15V 2k LT1206 • F07 Figure 7. Thermal Calculation Example The device dissipation can be found by measuring the supply currents, calculating the total dissipation, and then subtracting the dissipation in the load and feedback network. PD = (39mA × 30V) – (12V)2/(2k||2k) = 1.03W Then: TJ = (1.03W × 100°C/W) + 70°C = 173°C for the N8 package TJ = (1.03W × 65°C/W) × + 70°C = 137°C for the S8 with 225 sq. mm topside heat sinking TJ = (1.03W × 35°C/W) × + 70°C = 106°C for the R package with 100 sq. mm topside heat sinking Since the Maximum Junction Temperature is 150°C, the N8 package is clearly unacceptable. Both the S8 and R packages are usable. LT1206 TYPICAL APPLICATIO S Precision ×10 Hi Current Amplifier CMOS Logic to Shutdown Interface 15V VIN + LT1097 – 500pF 330Ω OUTPUT OFFSET: < 500µV SLEW RATE: 2V/µs BANDWIDTH: 4MHz STABLE WITH CL < 10nF 1k Low Noise ×10 Buffered Line Driver 15V 1µF 15V 1µF + LT1115 + + + 1µF + RG LT1206 S/D OUTPUT 0.01µF RL – –15V – 560Ω 909Ω – 15V 560Ω VIN LT1206 • TA04 100Ω RL = 32Ω VO = 5VRMS THD + NOISE = 0.0009% AT 1kHz = 0.004% AT 20kHz SMALL SIGNAL 0.1dB BANDWIDTH = 600kHz + 68pF U + LT1206 COMP – S/D + OUT 0.01µF 5V 10k 2N3904 – LT1206 S/D 24k LT1206 • TA05 3k –15V 10k LT1206 • TA03 Distribution Amplifier VIN 75Ω + – LT1206 S/D RF 75Ω 75Ω CABLE 75Ω 75Ω LT1206 • TA06 75Ω 1µF Buffer AV = 1 + – LT1206 COMP S/D VOUT 0.01µF* *OPTIONAL, USE WITH CAPACITIVE LOADS **VALUE OF RF DEPENDS ON SUPPLY VOLTAGE AND LOADING. SELECT FROM TYPICAL AC PERFORMANCE TABLE OR DETERMINE EMPIRICALLY RF** LT1206 • TA07 13 LT1206 PACKAGE DESCRIPTIO 0.300 – 0.320 (7.620 – 8.128) 0.009 – 0.015 (0.229 – 0.381) ( +0.025 0.325 –0.015 8.255 +0.635 –0.381 ) 0.060 (1.524) ( +0.012 0.331 –0.020 +0.305 8.407 –0.508 ) 0.050 ± 0.010 (1.270 ± 0.254) 0.030 ± 0.008 (0.762 ± 0.203) ( +0.012 0.143 –0.020 +0.305 3.632 –0.508 ) 14 U Dimensions in inches (millimeters) unless otherwise noted. N8 Package 8-Lead Plastic DIP 0.400 (10.160) MAX 8 7 6 5 0.250 ± 0.010 (6.350 ± 0.254) 1 2 3 4 0.045 – 0.065 (1.143 – 1.651) 0.130 ± 0.005 (3.302 ± 0.127) 0.065 (1.651) TYP 0.125 (3.175) MIN 0.020 (0.508) MIN 0.045 ± 0.015 (1.143 ± 0.381) 0.100 ± 0.010 (2.540 ± 0.254) 0.018 ± 0.003 (0.457 ± 0.076) N8 0392 R Package 7-Lead Plastic DD 0.401 ± 0.015 (10.185 ± 0.381) 0.175 ± 0.008 (4.445 ± 0.203) 15° TYP 0.050 ± 0.008 (1.270 ± 0.203) +0.008 0.004 –0.004 0.059 (1.499) TYP ( +0.203 0.102 –0.102 ) 0.105 ± 0.008 (2.667 ± 0.203) 0.022 ± 0.005 (0.559 ± 0.127) 0.050 ± 0.012 (1.270 ± 0.305) DD7 0693 LT1206 PACKAGE DESCRIPTIO 0.010 – 0.020 × 45° (0.254 – 0.508) 0.008 – 0.010 (0.203 – 0.254) 0°– 8° TYP 0.016 – 0.050 0.406 – 1.270 0.390 – 0.410 (9.91 – 10.41) 0.103 – 0.113 (2.62 – 2.87) 0.026 – 0.036 (0.66 – 0.91) 0.045 – 0.055 (1.14 – 1.40) 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 circuits as described herein will not infringe on existing patent rights. U Dimensions in inches (millimeters) unless otherwise noted. S8 Package 8-Lead Plastic SOIC 0.189 – 0.197 (4.801 – 5.004) 8 7 6 5 0.228 – 0.244 (5.791 – 6.197) 0.150 – 0.157 (3.810 – 3.988) 1 2 3 4 0.053 – 0.069 (1.346 – 1.752) 0.004 – 0.010 (0.101 – 0.254) 0.014 – 0.019 (0.355 – 0.483) 0.050 (1.270) BSC SO8 0392 Y Package 7-Lead TO-220 0.147 – 0.155 (3.73 – 3.94) DIA 0.169 – 0.185 (4.29 – 4.70) 0.045 – 0.055 (1.14 – 1.40) 0.235 – 0.258 (5.97 – 6.55) 0.560 – 0.590 (14.22 – 14.99) 0.620 (15.75) TYP 0.700 – 0.728 (17.78 – 18.49) 0.152 – 0.202 (3.86 – 5.13) 0.260 – 0.320 (6.60 – 8.13) 0.016 – 0.022 (0.41 – 0.56) 0.135 – 0.165 (3.43 – 4.19) 0.095 – 0.115 (2.41 – 2.92) 0.155 – 0.195 (3.94 – 4.95) Y7 0893 15 LT1206 U.S. Area Sales Offices NORTHEAST REGION Linear Technology Corporation One Oxford Valley 2300 E. Lincoln Hwy.,Suite 306 Langhorne, PA 19047 Phone: (215) 757-8578 FAX: (215) 757-5631 SOUTHEAST REGION Linear Technology Corporation 17060 Dallas Parkway Suite 208 Dallas, TX 75248 Phone: (214) 733-3071 FAX: (214) 380-5138 CENTRAL REGION Linear Technology Corporation Chesapeake Square 229 Mitchell Court, Suite A-25 Addison, IL 60101 Phone: (708) 620-6910 FAX: (708) 620-6977 SOUTHWEST REGION Linear Technology Corporation 22141 Ventura Blvd. Suite 206 Woodland Hills, CA 91364 Phone: (818) 703-0835 FAX: (818) 703-0517 NORTHWEST REGION Linear Technology Corporation 782 Sycamore Dr. Milpitas, CA 95035 Phone: (408) 428-2050 FAX: (408) 432-6331 Linear Technology Corporation 266 Lowell St., Suite B-8 Wilmington, MA 01887 Phone: (508) 658-3881 FAX: (508) 658-2701 International Sales Offices FRANCE Linear Technology S.A.R.L. Immeuble "Le Quartz" 58 Chemin de la Justice 92290 Chatenay Malabry France Phone: 33-1-41079555 FAX: 33-1-46314613 GERMANY Linear Techonolgy GMBH Untere Hauptstr. 9 D-85386 Eching Germany Phone: 49-89-3197410 FAX: 49-89-3194821 JAPAN Linear Technology KK 5F YZ Bldg. 4-4-12 Iidabashi, Chiyoda-Ku Tokyo, 102 Japan Phone: 81-3-3237-7891 FAX: 81-3-3237-8010 KOREA Linear Technology Korea Branch Namsong Building, #505 Itaewon-Dong 260-199 Yongsan-Ku, Seoul Korea Phone: 82-2-792-1617 FAX: 82-2-792-1619 SINGAPORE Linear Technology Pte. Ltd. 101 Boon Keng Road #02-15 Kallang Ind. Estates Singapore 1233 Phone: 65-293-5322 FAX: 65-292-0398 TAIWAN Linear Technology Corporation Rm. 801, No. 46, Sec. 2 Chung Shan N. Rd. Taipei, Taiwan, R.O.C. Phone: 886-2-521-7575 FAX: 886-2-562-2285 UNITED KINGDOM Linear Technology (UK) Ltd. The Coliseum, Riverside Way Camberley, Surrey GU15 3YL United Kingdom Phone: 44-276-677676 FAX: 44-276-64851 World Headquarters Linear Technology Corporation 1630 McCarthy Blvd. Milpitas, CA 95035-7487 Phone: (408) 432-1900 FAX: (408) 434-0507 06/24/93 16 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7487 (408) 432-1900 q FAX: (408) 434-0507 q TELEX: 499-3977 LT/GP 0993 10K REV 0 • PRINTED IN USA © LINEAR TECHNOLOGY CORPORATION 1993