LT1193CJ8

LT1193 Video Difference Amplifier FEATURES s s s s s s s s s s s s DESCRIPTIO Differential or Single-Ended Gain Block (Adjustable) –3dB Bandwidth, AV = ± 2: 80MHz Slew Rate: 500V/µs Low Cost Output Current: ± 50mA Settling Time: 180ns to 0.1% CMRR at 10MHz: > 40dB Differential Gain Error: 0.2% Differential Phase Error: 0.08° Single 5V Operation Drives Cables Directly Output Shutdown The LT®1193 is a video difference amplifier optimized for operation on ± 5V and a single 5V supply. This versatile amplifier features uncommitted high input impedance (+) and (–) inputs, and can be used in differential or singleended configurations. Additionally, a second set of inputs give gain adjustment and DC control to the differential amplifier. The LT1193’s high slew rate, 500V/µs, wide bandwidth, 80MHz, and ± 50mA output current make it ideal for driving cables directly. The shutdown feature reduces the power dissipation to a mere 15mW and allows multiple amplifiers to drive the same cable. The LT1193 is available in 8-pin PDIP and SO packages. , LTC and LT are registered trademarks of Linear Technology Corporation. APPLICATIO S s s s s s Line Receivers Video Signal Processing Cable Drivers Oscillators Tape and Disc Drive Systems TYPICAL APPLICATIO Cable Sense Amplifier for Loop Through Connections with DC Adjust VIN 5V 3 CABLE VDC 2 1 8 + – + – 7 LT1193 4 –5V 300Ω LT1193 • TA01 6 75Ω VOUT 75Ω 300Ω U 1193fb U U 1 LT1193 ABSOLUTE (Note 1) AXI U RATI GS PACKAGE/ORDER I FOR ATIO TOP VIEW +/REF 1 –IN 2 +IN 3 V– 4 N8 PACKAGE 8-LEAD PDIP 8 7 6 5 –/FB V+ OUT SHDN Total Supply Voltage (V + to V –) .............................. 18V Differential Input Voltage ........................................ ± 6V Input Voltage .......................................................... ± VS Output Short-Circuit Duration (Note 2) ......... Continuous Operating Temperature Range LT1193M (OBSOLETE) ................ – 55°C to 125°C LT1193C .................................................. 0°C to 70°C LT1193I ...............................................–40°C to 85°C Maximum Temperature ........................................ 150°C Storage Temperature Range ................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C ORDER PART NUMBER LT1193CN8 LT1193CS8 LT1193IS8 S8 PART MARKING 1193 1193I LT1193MJ8 LT1193CJ8 S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 100°C/W (N8) TJMAX = 150°C, θJA = 150°C/W (S8) J8 PACKAGE 8-LEAD CERDIP TJMAX = 150°C, θJA = 100°C/W OBSOLETE PACKAGE Consider the N8 or S8 Packages for Alternate Source Consult LTC Marketing for parts specified with wider operating temperature ranges. VS = ± 5V, VREF = 0V, RFB1 = 900Ω from Pins 6 to 8, RFB2 = 100Ω from Pin 8 to ground, RL = RFB1 + RFB2 = 1k (Note 3), TA = 25°C, CL ≤ 10pF, Pin 5 open circuit, unless otherwise noted. SYMBOL VOS IOS IB en in RIN CIN VIN(LIM) CMRR PSRR VOUT PARAMETER Input Offset Voltage Input Offset Current Input Bias Current Input Noise Voltage Input Noise Current Input Resistance Input Capacitance Input Voltage Limit Input Voltage Range Common Mode Rejection Ratio Power Supply Rejection Ratio Output Voltage Swing CONDITIONS Both Inputs (Note 4) All Packages Either Input Either Input fO = 10kHz fO = 10kHz Either Input Either Input (Note 5) VCM = – 2.5V to 3.5V VS = ± 2.375V to ± 8V VS = ± 5V, RL = 1k VS = ± 8V, RL = 1k VS = ± 8V, RL = 100Ω VO = ± 3V, RL = 1k RL = 100Ω VO = ± 2V, RL = 300Ω (Notes 6, 11) VO = 6VP-P (Note 7) AV = 50, VO = ± 1.5V, 20% to 80% (Note 11) RL= 1k, VO = ± 125mV, 50% to 50% VO = ± 50mV 3V Step, 0.1% (Note 8) RL = 150Ω, AV = 2 (Note 9) RL = 150Ω, AV = 2 (Note 9) MIN LT1193M/C/I TYP MAX 2 12 0.2 3 ± 0.5 ± 3.5 50 4 100 2 1.3 3.5 75 75 ±4 ±7 6.6 0.1 1.0 0.1 1.2 500 26.5 9 160 210 15 0 180 0.2 0.08 UNITS mV µA µA nV/√Hz pA/√Hz kΩ pF V V dB dB V V V % % V/µs MHz MHz ns ns % ns % DegP-P 1193fb ELECTRICAL CHARACTERISTICS – 2.5 60 60 ± 3.8 ± 6.8 6.4 GE SR FPBW BW tr, t f tPD ts Diff AV Diff Ph Gain Error Slew Rate Full-Power Bandwidth Small-Signal Bandwidth Rise Time, Fall Time Propagation Delay Overshoot Settling Time Differential Gain Differential Phase 350 18.5 110 2 U W U U WW W LT1193 ELECTRICAL CHARACTERISTICS SYMBOL IS ISHDN tON tOFF PARAMETER Supply Current Shutdown Supply Current Shutdown Pin Current Turn On Time Turn Off Time VS = ±5V, VREF = 0V, RFB1 = 900Ω from Pins 6 to 8, RFB2 = 100Ω from Pin 8 to ground, RL = RFB1 + RFB2 = 1k (Note 3), TA = 25°C, CL ≤ 10pF, Pin 5 open circuit, unless otherwise noted. CONDITIONS Pin 5 at V– MIN LT1193M/C/I TYP MAX 35 1.3 20 300 200 Pin 5 at V – Pin 5 from V – to Ground, RL = 1k Pin 5 from Ground to V –, RL = 1k 43 2 50 UNITS mA mA µA ns ns VS+ = 5V, VS – = 0V, VREF = 2.5V, RFB1 = 900Ω from Pins 6 to 8, RFB2 = 100Ω from Pin 8 to VREF, RL = RFB1 + RFB2 = 1k (Note 3), TA = 25°C, CL ≤ 10pF, Pin 5 open circuit, unless otherwise noted. SYMBOL VOS IOS IB CMRR VOUT SR BW IS ISHDN PARAMETER Input Offset Voltage Input Offset Current Input Bias Current Input Voltage Range Common Mode Rejection Ratio Output Voltage Swing Slew Rate Small-Signal Bandwidth Supply Current Shutdown Supply Current Shutdown Pin Current Pin 5 at V– Pin 5 at V – VCM = 2V to 3.5V RL = 100Ω to Ground VO = 1V to 3V VOUT High VOUT Low CONDITIONS Both Inputs (Note 4) All Packages Either Input Either Input 2 55 3.6 70 3.8 0.25 250 8 32 1.3 20 40 2 50 0.4 MIN LT1193M/C/I TYP MAX 3 0.2 ± 0.5 15 3 ± 3.5 3.5 UNITS mV µA µA V dB V V V/µs MHz mA mA µA The q denotes the specificatons which apply over the full operating temperature range of – 55°C ≤ TA ≤ 125°C. VS = ± 5V, VREF = 0V, RFB1 = 900Ω from Pins 6 to 8, RFB2 = 100Ω from Pin 8 to ground, RL = RFB2 = 1k (Note 3), CL ≤ 10pF, Pin 5 open circuit, unless otherwise noted. SYMBOL VOS ∆VOS /∆T IOS IB CMRR PSRR VOUT GE IS ISHDN PARAMETER Input Offset Voltage Input VOS Drift Input Offset Current Input Bias Current Input Voltage Range Common Mode Rejection Ratio Power Supply Rejection Ratio Output Voltage Swing Gain Error Supply Current Shutdown Supply Current Shutdown Pin Current Pin 5 at V – (Note 10) Pin 5 at V– VCM = – 2.5V to 3.5V VS = ± 2.375V to ± 5V RL = 1k VS = ±8V, RL = 100Ω VO = ± 3V, RL = 1k CONDITIONS q q q q q q q q q q q q q MIN LT1193M TYP 2 20 0.8 ±1 MAX 16 5 ±5.5 3.5 UNITS mV µV/°C µA µA V dB dB V –2.5 53 53 3.6 6 70 70 4 6.5 0.2 35 1.3 20 1.2 43 2.2 % mA mA µA 1193fb 3 LT1193 ELECTRICAL CHARACTERISTICS The q denotes the specificatons which apply over the full operating temperature range of – 40°C ≤ TA ≤ 85°C. VS = ± 5V, VREF = 0V, RFB1 = 900Ω from Pins 6 to 8, RFB2 = 100Ω from Pin 8 to ground, RL = RFB2 = 1k (Note 3), CL ≤ 10pF, Pin 5 open circuit, unless otherwise noted. SYMBOL VOS ∆VOS /∆T IOS IB CMRR PSRR VOUT GE IS ISHDN PARAMETER Input Offset Voltage Input VOS Drift Input Offset Current Input Bias Current Input Voltage Range Common Mode Rejection Ratio Power Supply Rejection Ratio Output Voltage Swing Gain Error Supply Current Shutdown Supply Current Shutdown Pin Current CONDITIONS SO-8 Package MIN q q q q q LT1193I TYP 2 20 0.8 ±1 70 70 4 6.5 0.2 35 1.3 20 MAX 20 5 ±5.5 3.5 VCM = – 2.5V to 3.5V VS = ± 2.375V to ± 5V RL = 1k VS = ± 8V, RL = 100Ω VO = ± 3V, RL = 1k Pin 5 at V – (Note 10) Pin 5 at V – q q q q q q q q –2.5 53 53 3.6 6 UNITS mV µV/°C µA µA V dB dB V % mA mA µA 1.2 43 2.2 The q denotes the specificatons which apply over the full operating temperature range of 0°C ≤ TA ≤ 70°C. VS = ± 5V, VREF = 0V, RFB1 = 900Ω from Pins 6 to 8, RFB2 = 100Ω from Pin 8 to ground, RL = RFB1 + RFB2 = 1k (Note 3), CL ≤ 10pF, Pin 5 open circuit, unless otherwise noted. SYMBOL VOS ∆VOS /∆T IOS IB CMRR PSRR VOUT GE IS ISHDN PARAMETER Input Offset Voltage Input VOS Drift Input Offset Current Input Bias Current Input Voltage Range Common Mode Rejection Ratio Power Supply Rejection Ratio Output Voltage Swing Gain Error Supply Current Shutdown Supply Current Shutdown Pin Current CONDITIONS N8 Package SO-8 Package MIN q q q q q q LT1193C TYP 2 20 0.2 ±0.5 MAX 14 20 3.5 ±4 3.5 VCM = – 2.5V to 3.5V VS = ± 2.375V to ± 5V RL = 1k RL = 100Ω VO = ± 3V, RL = 1k Pin 5 at V – (Note 10) Pin 5 at V – q q q q q q q q –2.5 55 55 3.7 6.2 70 70 4 6.6 0.2 35 1.3 20 1.2 43 2.1 UNITS mV mV µV/°C µA µA V dB dB V V % mA mA µA Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: A heat sink is required to keep the junction temperature below absolute maximum when the output is shorted. Note 3: When RL = 1k is specified, the load resistor is RFB1 + RFB2, but when RL = 100Ω is specified, then an additional 100Ω is added to the output. Note 4: VOS measured at the output (Pin 6) is the contribution from both input pair, and is input referred. Note 5: VIN LIM is the maximum voltage between –VIN and +VIN (Pin 2 and Pin 3) for which the output can respond. Note 6: Slew rate is measured between ± 2V on the output, with a ± 1V input step, AV = 3. Note 7: Full-power bandwidth is calculated from the slew rate measurement: FPBW = SR/2πVP. Note 8: Settling time measurement techniques are shown in “Take the Guesswork Out of Settling Time Measurements,” EDN, September 19, 1985. Note 9: NTSC (3.58MHz). Note 10: See Applications section for shutdown at elevated temperatures. Do not operate the shutdown above TJ > 125°C. Note 11: 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). 1193fb 4 LT1193 TYPICAL PERFOR A CE CHARACTERISTICS Input Bias Current vs Common Mode Voltage 4 3 VS = ± 5V INPUT BIAS CURRENT (µA) –0.3 COMMON MODE VOLTAGE (V) INPUT BIAS CURRENT (µA) 2 1 25°C 0 –1 –2 –4 –3 1 3 –2 –1 0 2 COMMON MODE VOLTAGE (V) 4 –55°C 125°C Equivalent Input Noise Voltage vs Frequency EQUIVALENT INPUT NOISE CURRENT (pA/√Hz) EQUIVALENT INPUT NOISE VOLTAGE (nV/√Hz) 400 350 300 250 200 150 100 50 0 10 100 SUPPLY CURRENT (mA) 1k 10k FREQUENCY (Hz) Shutdown Supply Current vs Temperature 5.0 SHUTDOWN SUPPLY CURRENT (mA) 4.5 VS = ± 5V 3 3.5 3.0 VSHDN = – VEE + 0.2V 2.5 2.0 VSHDN = –VEE 1.5 1.0 –50 –25 0 25 75 50 TEMPERATURE (°C) 100 125 GAIN ERROR (%) 1 RL = 100Ω OPEN-LOOP GAIN (V/V) 4.0 VSHDN = – VEE + 0.4V UW LT1193 • TPC01 Input Bias Current vs Temperature VS = ± 5V 10 8 6 4 2 0 –2 –4 –6 –8 –0.8 –50 –10 –25 50 0 25 75 TEMPERATURE (°C) 100 125 Common Mode Voltage vs Supply Voltage –55°C 25°C +V COMMON MODE 125°C –0.4 +IB –0.5 IOS –0.6 –IB –0.7 –V COMMON MODE –55°C 25°C 125°C 0 2 6 4 8 ± V SUPPLY VOLTAGE (V) 10 LT1193 • TPC02 LT1193 • TPC03 Equivalent Input Noise Current vs Frequency 80 VS = ± 5V TA = 25°C RS = 100k 50 Supply Current vs Supply Voltage VS = ± 5V TA = 25°C R S = 0Ω 60 40 –55°C 30 25°C 125°C 40 20 20 10 0 10 100 1k 10k FREQUENCY (Hz) 100k 0 0 2 4 6 8 ± SUPPLY VOLTAGE (V) 10 100k LT1193 • TPC04 LT1193 • TPC05 LT1193 • TPC06 Gain Error vs Temperature VS = ± 5V Open-Loop Gain vs Temperature 20k VS = ± 5V VO = ± 3V RL = 1k 2 15k 0 RL = 1k 10k 5k RL = 100Ω 0 –50 –25 –1 –2 –50 –25 25 0 50 75 TEMPERATURE (°C) 100 125 25 75 0 50 TEMPERATURE (°C) 100 125 LT1193 • TPC07 LT1193 • TPC08 LT1193 • TPC09 1193fb 5 LT1193 TYPICAL PERFOR A CE CHARACTERISTICS Gain, Phase vs Frequency 100 80 100 80 60 40 20 0 –20 100M LT1193 • TPC11 PHASE 15k GAIN BANDWIDTH PRODUCT (MHz) OPEN-LOOP VOLTAGE GAIN (V/V) VOLTAGE GAIN (dB) 60 40 20 0 VS = ±5V TA = 25°C RL = 1 k –20 100k GAIN 1M 10M FREQUENCY (Hz) Gain Bandwidth Product and Unity Gain Phase Margin vs Temperature 70 GAIN BANDWIDTH PRODUCT (MHz) 65 60 55 50 45 40 35 30 –50 –25 25 75 0 50 TEMPERATURE (°C) GAIN BANDWIDTH PRODUCT 65 60 55 50 OUTPUT IMPEDANCE (Ω ) COMMON MODE REJECTION RATIO (dB) UNITY GAIN PHASE MARGIN Power Supply Rejection Ratio vs Frequency 80 OUTPUT SHORT-CIRCUIT CURRENT (mA) POWER SUPPLY REJECTION RATIO (dB) 60 +PSRR –PSRR VS = ± 5V TA = 25 °C VRIPPLE = ± 300mV 90 40 OUTPUT SWING (V) 20 0 –20 1k 10k 1M 100k FREQUENCY (Hz) 10M 100M 6 UW VS = ±5V RL = 1 k 100 LT1193 • TPC13 Open-Loop Voltage Gain vs Load Resistance 20k VS = ±5V VO = ±3V TA = 25°C 80 Gain Bandwidth Product vs Supply Voltage PHASE MARGIN (DEGREES) PHASE MARGIN (DEGREES) 70 10k TA = – 55°C, 25°C, 125°C 60 5k 0 10 100 LOAD RESISTANCE (Ω) 1000 LT1193 • TPC10 50 0 2 6 4 8 ± SUPPLY VOLTAGE (V) 10 LT1193 • TPC12 Output Impedance vs Frequency 100 VS = ±5V TA = 25°C 80 Common Mode Rejection Ratio vs Frequency VS = ±5V TA = 25°C RL = 1k 70 10 AV = 10 70 1 60 45 40 35 30 125 0.1 AV = 2 50 0.01 40 0.001 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M 30 100k 1M 10M FREQUENCY (Hz) 100M LT1193 • TPC15 LT1193 • TPC14 Output Short-Circuit Current vs Temperature 100 VS = ± 5V 10 8 6 4 2 0 –2 –4 –6 –8 70 –50 –10 –25 50 0 25 75 TEMPERATURE (°C) 100 125 Output Swing vs Supply Voltage RL = 1k +VOUT, 25°C, 125°C, –55°C 80 –VOUT, –55°C, 25°C, 125°C 0 2 8 4 6 ± V SUPPLY VOLTAGE (V) 10 LT1193 • TPC16 LT1193 • TPC17 LT1193 • TPC18 1193fb LT1193 TYPICAL PERFOR A CE CHARACTERISTICS Output Voltage Swing vs Load Resistance 5 VS = ± 5V TA = – 55°C TA = 25°C TA = 125°C 900 800 – SLEW RATE OUTPUT VOLTAGE SWING (V) OUTPUT VOLTAGE STEP (V) 3 SLEW RATE (V/µs) 1 –1 TA = 125°C TA = – 55°C, 25°C –5 10 100 LOAD RESISTANCE (Ω) 1000 LT1193 • TPC19 –3 Large-Signal Transient Response AV = 2, RL = 150Ω, RFB = 300Ω, RG = 300Ω APPLICATIO S I FOR ATIO The LT1193 is a video difference amplifier which has two uncommitted high input impedance (+) and (–) inputs. The amplifier has one set of inputs that can be used for reference and feedback. Additionally, this set of inputs give gain adjust and DC control to the differential amplifier. The voltage gain of the LT1193 is set like a conventional operational amplifier. Feedback is applied to Pin 8 and it is optimized for gains of 2 or greater. The amplifier can be operated single-ended by connecting either the (+) or (–) inputs to +/REF, Pin 1. The voltage gain is set by the resistors: (RFB + RG)/RG. The primary usefulness of the LT1193 is in converting high speed differential signals to a single-ended output. The amplifier has common mode rejection beyond 50MHz U W UW LT1193 • TPC22 Slew Rate vs Temperature 4 Output Voltage Step vs Settling Time, AV = 2 VS = ± 5V TA = 25°C RL = 1k 10mV 2 700 600 500 +SLEW RATE 0 VS = ± 5V 400 TA = 25°C RL = 1k VO = ± 2V 300 –50 –25 0 25 50 75 TEMPERATURE (°C) –2 10mV –4 100 125 40 50 60 70 80 SETTLING TIME (ns) 90 100 LT1193 • TPC20 LT1193 • TPC21 Small-Signal Transient Response Small-Signal Transient Response LT1193 • TPC23 LT1193 • TPC24 AV = – 10, SMALL-SIGNAL RISE TIME = 43ns AV = 2, RFB = 300Ω, RG = 300Ω, OVERSHOOT = 25%, RISE TIME = 4.7ns UU and a full-power bandwidth of 40MHz at 4VP-P. Like the single-ended case, the differential voltage gain is set by the external resistors: (RFB + RG)/RG. The maximum input differential signal for which the output will respond is approximately ±1.3V. Power Supply Bypassing The LT1193 is quite tolerant of power supply bypassing. In some applications a 0.1µF ceramic disc capacitor placed 1/2 inch from the amplifier is all that is required. A scope photo of the amplifier output with no supply bypassing is used to demonstrate this bypassing tolerance, RL = 1k. 1193fb 7 LT1193 APPLICATIO S I FOR ATIO SHDN VIN 3 2 5 V+ 3 2 SHDN 5 V+ 7 + – LT1193 6 VIN 7 + – LT1193 1 +/REF 8 –/FB 4 VOUT 1 +/REF 8 –/FB 4 V– RFB RG R + RG AV = + FB RG RG V– RFB R + RG AV = – FB RG SHDN SHDN 3 2 5 V+ VINDIFF VOUT VIN RG 3 2 7 + – LT1193 5 V+ LT1192 • TA05 VINDIFF VIN 1 +/REF 8 –/FB 4 6 1 +/REF 8 –/FB 4 7 + – LT1193 V– RFB R + RG VO = (VINDIFF + VIN) FB RG RG FB G V– RFB VO = (R R+ R ( V G INDIFF – No Supply Bypass Capacitors LT1192 • TA04 AV = 10, IN DEMO BOARD, RL = 1k In many applications and those requiring good settling time it is important to use multiple bypass capacitors. A 0.1µF ceramic disc in parallel with a 4.7µF tantalum is recommended. Two oscilloscope photos with different bypass conditions are used to illustrate the settling time characteristics of the amplifier. Note that although the output waveform looks acceptable at 1V/DIV, when amplified to 10mV/DIV the settling time to 10mV is 347ns for the 0.1µF bypass; the time drops to 96ns with multiple bypass capacitors. 8 U Settling Time Poor Bypass 6 VOUT W UU VOUT 1V/DIV 0V 0V VOUT 10mV/DIV 6 VOUT SETTLING TIME TO 10mV, AV = 2 SUPPLY BYPASS CAPACITORS = 0.1µF Settling Time Good Bypass ( RR ( V FB G IN LT1193 • TA03 VOUT 1V/DIV 0V 0V VOUT 10mV/DIV LT1192 • TA06 SETTLING TIME TO 10mV, AV = 2 SUPPLY BYPASS CAPACITORS = 0.1µF + 4.7µF TANTALUM Operating With Low Closed-Loop Gains The LT1193 has been optimized for closed-loop gains of 2 or greater; the frequency response illustrates the obtainable closed-loop bandwidths. For a closed-loop gain of 2 the response peaks about 2dB. Peaking can be minimized by keeping the feedback elements below 1kΩ, and can be eliminated by placing a capacitor across the feedback resistor, (feedback zero). This peaking shows up as time domain overshoot of about 40%. With the feedback capacitor it is eliminated. Cable Terminations The LT1193 video difference amplifier has been optimized as a low cost cable driver. The ±50mA guaranteed output current enables the LT1193 to easily deliver 7.5VP-P into 1193fb LT1193 APPLICATIO S I FOR ATIO Closed-Loop Voltage Gain vs Frequency 25 CLOSED-LOOP VOLTAGE GAIN (dB) AV = 10 VS = ± 5V TA = 25°C 15 AV = 5 AV = 3 AV = 2 5 –5 100k 1M 10M FREQUENCY (Hz) 100M LT1193 • TA07 Closed-Loop Voltage Gain vs Frequency 10 CLOSED-LOOP VOLTAGE GAIN (dB) 8 VS = ± 5V TA = 25°C AV = 2 RFB = 300Ω RG = 300Ω CFB = 0pF CFB = 5pF 6 CFB = 10pF 4 CFB = 15pF RG 2 CLOSED LOOP VOLTAGE GAIN (dB) 0 100k 1M 10M FREQUENCY (Hz) 100M LT1193 • TA08 Small-Signal Transient Response LT1193 • TA09 AV = 2, OVERSHOOT = 40%, RFB = 1k, RG = 1k 100Ω, while operating on ± 5V supplies and gains > 3. On a single 5V supply, the LT1193 can swing 2.6V P-P for gains ≥ 2. U Small-Signal Transient Response LT1193 • TA10 W UU AV = 2 WITH 8pF FEEDBACK CAPACITOR RISE TIME = 3.75ns, RFB = 1k, RG = 1k Double Terminated Cable Driver 5V 3+ 7 2– LT1193 1 8 6 75Ω CABLE 75Ω + – 4 –5V RFB CFB Closed-Loop Voltage Gain vs Frequency 8 6 4 2 0 –2 –4 –6 100k AV = 1 RFB = 300Ω RG = 300Ω CFB = 10pF AV = 2 RFB = 300Ω RG = 100Ω CFB = 0pF 1M 10M 100M LT1193 • TA11 FREQUENCY (Hz) When driving a cable it is important to terminate the cable to avoid unwanted reflections. This can be done in one of two ways: single termination or double termination. With single termination, the cable must be terminated at the receiving end (75Ω to ground) to absorb unwanted energy. The best performance can be obtained by double termination (75Ω in series with the output of the amplifier, and 75Ω to ground at the other end of the cable). This 1193fb 9 LT1193 APPLICATIO S I FOR ATIO termination is preferred because reflected energy is absorbed at each end of the cable. When using the double termination technique it is important to note that the signal is attenuated by a factor of 2, or 6dB. The cable driver has a – 3dB bandwidth of 80MHz while driving a 150Ω load. Using the Shutdown Feature The LT1193 has a unique feature that allows the amplifier to be shut down for conserving power or for multiplexing several amplifiers onto a common cable. The amplifier will shut down by taking Pin 5 to V –. In shutdown, the amplifier dissipates 15mW while maintaining a true high impedance output state of 15kΩ in parallel with the feedback resistors. The amplifiers may be connected inverting, noninverting or differential for MUX applications. When the output is loaded with as little as 1kΩ from the amplifier’s feedback resistors, the amplifier shuts off in 200ns. This shutoff can be under the control of HC CMOS operating between 0V and – 5V. Output Shutdown tON = 300ns tOFF = 200ns LT1193 • TA12 1MHz SINE WAVE GATED OFF WITH SHUTDOWN PIN, AV = 3, RFB = 1k, RG = 500Ω The ability to maintain shutoff is shown on the curve Shutdown Supply Current vs Temperature in the Typical Performance Characteristics section. At very high elevated temperatures it is important to hold the SHDN pin close to the negative supply to keep the supply current from increasing. Murphy Circuits There are several precautions the user should take when using the LT1193 in order to realize its full capability. Although the LT1193 can drive a 30pF in gains as low as 2, LT1193 • TA15 10 U isolating the capacitance with 10Ω can be helpful. Precautions primarily have to do with driving large capacitive loads. Other precautions include: 1. Use a ground plane (see Design Note 50, High Frequency Amplifier Evaluation Board). 2. Do not use high source impedances. The input capacitance of 2pF, and RS = 10k for instance, will give an 8MHz – 3dB bandwidth. 3. PC board socket may reduce stability. 4. A feedback resistor of 1k or lower reduces the effects of stray capacitance at the inverting input. (For instance, closed-loop gain of ± 2 can use RFB = 300Ω and RG = 300Ω.) Driving Capacitive Load LT1193 • TA14 W UU AV = 2, IN DEMO BOARD, CL = 30pF, RFB = 1k, RG = 1k Driving Capacitive Load AV = 2, IN DEMO BOARD, CL = 30pF WITH 10Ω ISOLATING RESISTOR 1193fb LT1193 APPLICATIO S I FOR ATIO 5V 3 2 1 8 + – + – 7 LT1193 4 –5V 6 COAX An Unterminated Cable Is a Large Capacitive Load SI PLIFIED SCHE ATIC 7 V+ VBIAS VBIAS + – 3 C FF 2 +V +V 5 SHDN 1 +/REF 8 –/FB * SUBSTRATE DIODE, DO NOT FORWARD BIAS 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. U Murphy Circuits 5V 3 2 1 8 W W UU + – + – 5V 3 6 2 1 7 LT1193 4 –5V + – + – 7 LT1193 4 –5V 6 1X SCOPE PROBE 8 SCOPE PROBE LT1193 • TA13 A 1X Scope Probe Is a Large Capacitive Load A Scope Probe on the Inverting Input Reduces Phase Margin W CM 6 VOUT * 4 V– LT1193 • TA16 1193fb 11 LT1193 PACKAGE DESCRIPTIO U J8 Package 8-Lead CERDIP (Narrow .300 Inch, Hermetic) (Reference LTC DWG # 05-08-1110) .300 BSC (7.62 BSC) CORNER LEADS OPTION (4 PLCS) .200 (5.080) MAX .015 – .060 (0.381 – 1.524) .005 (0.127) MIN 8 .405 (10.287) MAX 7 6 5 .023 – .045 (0.584 – 1.143) HALF LEAD OPTION .025 (0.635) RAD TYP 1 .045 – .065 (1.143 – 1.651) .014 – .026 (0.360 – 0.660) .100 (2.54) BSC .125 3.175 MIN 2 3 .220 – .310 (5.588 – 7.874) 4 J8 0801 .008 – .018 (0.203 – 0.457) 0° – 15° .045 – .068 (1.143 – 1.650) FULL LEAD OPTION NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE OR TIN PLATE LEADS OBSOLETE PACKAGE N8 Package 8-Lead PDIP (Narrow .300 Inch) (Reference LTC DWG # 05-08-1510) .300 – .325 (7.620 – 8.255) .045 – .065 (1.143 – 1.651) .130 ± .005 (3.302 ± 0.127) .400* (10.160) MAX 8 7 6 5 .008 – .015 (0.203 – 0.381) .065 (1.651) TYP .120 (3.048) .020 MIN (0.508) MIN .018 ± .003 (0.457 ± 0.076) .255 ± .015* (6.477 ± 0.381) ( +.035 .325 –.015 +0.889 8.255 –0.381 ) 1 2 3 4 N8 1002 .100 (2.54) BSC INCHES MILLIMETERS *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm) NOTE: 1. DIMENSIONS ARE S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610) .189 – .197 (4.801 – 5.004) NOTE 3 .010 – .020 × 45° (0.254 – 0.508) .008 – .010 (0.203 – 0.254) .053 – .069 (1.346 – 1.752) 0°– 8° TYP .228 – .244 (5.791 – 6.197) .150 – .157 .245 (3.810 – 3.988) MIN NOTE 3 .160 ±.005 .004 – .010 (0.101 – 0.254) 8 7 6 5 .050 BSC .045 ±.005 .016 – .050 (0.406 – 1.270) NOTE: 1. DIMENSIONS IN INCHES (MILLIMETERS) 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) .014 – .019 (0.355 – 0.483) TYP .050 (1.270) BSC 1 2 3 4 .030 ±.005 TYP SO8 0303 RECOMMENDED SOLDER PAD LAYOUT RELATED PARTS PART NUMBER LT1194 DESCRIPTION Video Difference Amp COMMENTS AV = 10 Version of the LT1193 1193fb LT/TP 0903 1K REV B • PRINTED IN USA 12 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 q FAX: (408) 434-0507 q www.linear.com © LINEAR TECHNOLOGY CORPORATION 1991