LT1193 Video Difference Amplifier U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO 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. 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 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. U APPLICATIO S ■ ■ ■ ■ , LTC and LT are registered trademarks of Linear Technology Corporation. Line Receivers Video Signal Processing Cable Drivers Oscillators Tape and Disc Drive Systems U ■ The LT1193 is available in 8-pin PDIP and SO packages. TYPICAL APPLICATIO Cable Sense Amplifier for Loop Through Connections with DC Adjust VIN 5V 3 CABLE 2 VDC 1 8 + – + – 7 LT1193 6 75Ω VOUT 75Ω 4 –5V 300Ω LT1193 • TA01 300Ω 1193fb 1 LT1193 W W W AXI U U ABSOLUTE RATI GS U U W PACKAGE/ORDER I FOR ATIO (Note 1) 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 TOP VIEW +/REF 1 8 –/FB –IN 2 7 V+ +IN 3 6 OUT V– 4 5 SHDN N8 PACKAGE 8-LEAD PDIP S8 PACKAGE 8-LEAD PLASTIC SO LT1193CN8 LT1193CS8 LT1193IS8 S8 PART MARKING TJMAX = 150°C, θJA = 100°C/W (N8) TJMAX = 150°C, θJA = 150°C/W (S8) 1193 1193I J8 PACKAGE 8-LEAD CERDIP TJMAX = 150°C, θJA = 100°C/W LT1193MJ8 LT1193CJ8 OBSOLETE PACKAGE Consider the N8 or S8 Packages for Alternate Source Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS 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 GE Gain Error SR FPBW BW tr, t f tPD Slew Rate Full-Power Bandwidth Small-Signal Bandwidth Rise Time, Fall Time Propagation Delay Overshoot Settling Time Differential Gain Differential Phase ts Diff AV Diff Ph 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 – 2.5 60 60 ±3.8 ±6.8 6.4 350 18.5 110 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 2 LT1193 ELECTRICAL CHARACTERISTICS 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 PARAMETER IS Supply Current CONDITIONS MIN LT1193M/C/I TYP MAX 35 UNITS 43 mA 1.3 2 mA 20 50 µA Shutdown Supply Current Pin 5 at V– Shutdown Pin Current Pin 5 at V – tON Turn On Time 300 ns tOFF Turn Off Time Pin 5 from V – to Ground, RL = 1k Pin 5 from Ground to V –, RL = 1k 200 ns ISHDN 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 PARAMETER CONDITIONS MIN VOS Input Offset Voltage Both Inputs (Note 4) All Packages IOS Input Offset Current Either Input IB Input Bias Current Either Input 3 Input Voltage Range Common Mode Rejection Ratio VCM = 2V to 3.5V VOUT Output Voltage Swing RL = 100Ω to Ground VOUT High Slew Rate Small-Signal Bandwidth IS Supply Current ISHDN mV 0.2 3 µA ±0.5 ±3.5 µA 3.5 V 55 70 dB 3.6 3.8 V VOUT Low BW 0.25 VO = 1V to 3V Shutdown Supply Current Pin 5 at Shutdown Pin Current Pin 5 at V – 0.4 V 250 V/µs 8 MHz 32 V– UNITS 15 2 CMRR SR LT1193M/C/I TYP MAX 40 mA 1.3 2 mA 20 50 µA The ● 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 PARAMETER CONDITIONS MIN LT1193M TYP MAX 16 UNITS VOS Input Offset Voltage ● 2 ∆VOS /∆T Input VOS Drift ● 20 IOS Input Offset Current ● 0.8 5 µA IB Input Bias Current ● ±1 ±5.5 µA Input Voltage Range ● –2.5 3.5 V VCM = – 2.5V to 3.5V ● 53 70 dB CMRR Common Mode Rejection Ratio mV µV/°C PSRR Power Supply Rejection Ratio VS = ± 2.375V to ± 5V ● 53 70 dB VOUT Output Voltage Swing RL = 1k ● 3.6 4 V VS = ±8V, RL = 100Ω ● 6 6.5 VO = ± 3V, RL = 1k ● 0.2 1.2 % ● 35 43 mA ● 1.3 2.2 mA ● 20 GE Gain Error IS Supply Current Shutdown Supply Current ISHDN Shutdown Pin Current Pin 5 at V – (Note 10) Pin 5 at V– µA 1193fb 3 LT1193 ELECTRICAL CHARACTERISTICS The ● 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 ● ● ● ● ● VCM = – 2.5V to 3.5V VS = ± 2.375V to ± 5V RL = 1k VS = ±8V, RL = 100Ω VO = ± 3V, RL = 1k ● ● ● ● –2.5 53 53 3.6 6 ● ● Pin 5 at V – (Note 10) Pin 5 at V – ● ● 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 1.2 43 2.2 UNITS mV µV/°C µA µA V dB dB V % mA mA µA The ● 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 PARAMETER Input Offset Voltage ∆VOS /∆T IOS IB Input VOS Drift Input Offset Current Input Bias Current Input Voltage Range Common Mode Rejection Ratio Power Supply Rejection Ratio Output Voltage Swing CMRR PSRR VOUT GE IS ISHDN Gain Error Supply Current Shutdown Supply Current Shutdown Pin Current CONDITIONS N8 Package SO-8 Package MIN ● ● 20 0.2 ±0.5 ● ● ● ● 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 – 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. ● ● LT1193C TYP 2 –2.5 55 55 3.7 6.2 70 70 4 6.6 0.2 35 1.3 20 MAX 14 20 3.5 ±4 3.5 1.2 43 2.1 UNITS mV mV µV/°C µA µA V dB dB V V % mA mA µA 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 U W TYPICAL PERFOR A CE CHARACTERISTICS Input Bias Current vs Common Mode Voltage –0.3 VS = ±5V INPUT BIAS CURRENT (µA) INPUT BIAS CURRENT (µA) 3 2 1 25°C 0 Common Mode Voltage vs Supply Voltage –55°C 125°C –1 10 VS = ±5V –0.4 +IB –0.5 IOS –0.6 –IB –0.7 –55°C 25°C 8 COMMON MODE VOLTAGE (V) 4 Input Bias Current vs Temperature 6 +V COMMON MODE 125°C 4 2 0 –2 –55°C 25°C 125°C –4 –V COMMON MODE –6 –8 –0.8 –50 –2 –4 –3 1 3 –2 –1 0 2 COMMON MODE VOLTAGE (V) 4 –10 –25 50 0 25 75 TEMPERATURE (°C) 100 LT1193 • TPC01 200 150 100 50 0 100 10 1k 10k FREQUENCY (Hz) VS = ±5V TA = 25°C RS = 100k 60 40 20 0 10 100k –55°C 30 125°C 20 100 1k 10k FREQUENCY (Hz) 0 100k VS = ±5V VS = ±5V 2.0 0 OPEN-LOOP GAIN (V/V) 2.5 GAIN ERROR (%) VSHDN = –VEE + 0.2V 1 RL = 100Ω RL = 1k VS = ±5V VO = ±3V 15k 10k 5k RL = 100Ω 1.5 –25 0 25 75 50 TEMPERATURE (°C) RL = 1k –1 VSHDN = –VEE 1.0 –50 10 Open-Loop Gain vs Temperature 20k 2 VSHDN = –VEE + 0.4V 3.0 4 6 8 ±SUPPLY VOLTAGE (V) LT1193 • TPC06 Gain Error vs Temperature 3 3.5 2 0 4.5 4.0 25°C LT1193 • TPC05 Shutdown Supply Current vs Temperature SHUTDOWN SUPPLY CURRENT (mA) 40 10 LT1193 • TPC04 5.0 Supply Current vs Supply Voltage 50 SUPPLY CURRENT (mA) 250 EQUIVALENT INPUT NOISE CURRENT (pA/√Hz) EQUIVALENT INPUT NOISE VOLTAGE (nV/√Hz) 300 80 10 LT1193 • TPC03 Equivalent Input Noise Current vs Frequency VS = ±5V TA = 25°C RS = 0Ω 350 6 4 8 ±V SUPPLY VOLTAGE (V) LT1193 • TPC02 Equivalent Input Noise Voltage vs Frequency 400 2 0 125 100 125 LT1193 • TPC07 –2 –50 –25 25 0 50 75 TEMPERATURE (°C) 100 125 LT1193 • TPC08 0 –50 –25 25 75 0 50 TEMPERATURE (°C) 100 125 LT1193 • TPC09 1193fb 5 LT1193 U W TYPICAL PERFOR A CE CHARACTERISTICS Open-Loop Voltage Gain vs Load Resistance 80 60 60 40 40 GAIN 20 20 0 VS = ±5V TA = 25°C RL = 1k –20 100k 0 15k 10k 5k –20 100M 1M 10M FREQUENCY (Hz) 80 VS = ±5V VO = ±3V TA = 25°C 100 LOAD RESISTANCE (Ω) 10 LT1193 • TPC11 60 65 60 GAIN BANDWIDTH PRODUCT 55 55 50 50 UNITY GAIN PHASE MARGIN 45 45 40 40 35 35 30 –50 –25 25 75 0 50 TEMPERATURE (°C) 100 100 70 30 125 AV = 10 1 AV = 2 0.1 0.01 0.001 1k 10k 100k 1M FREQUENCY (Hz) 10M 20 0 –20 1k 10k 1M 100k FREQUENCY (Hz) 10M 60 50 40 30 100k 100M 100M LT1193 • TPC16 1M 10M FREQUENCY (Hz) 100M LT1193 • TPC15 Output Swing vs Supply Voltage 10 VS = ± 5V RL = 1k 8 +VOUT, 25°C, 125°C, –55°C 6 OUTPUT SWING (V) +PSRR –PSRR 40 100 OUTPUT SHORT-CIRCUIT CURRENT (mA) POWER SUPPLY REJECTION RATIO (dB) 60 70 Output Short-Circuit Current vs Temperature VS = ±5V TA = 25 °C VRIPPLE = ±300mV VS = ±5V TA = 25°C RL = 1k LT1193 • TPC14 Power Supply Rejection Ratio vs Frequency 10 LT1193 • TPC12 80 VS = ±5V TA = 25°C LT1193 • TPC13 80 6 4 8 ±SUPPLY VOLTAGE (V) Common Mode Rejection Ratio vs Frequency 10 OUTPUT IMPEDANCE (Ω ) 65 2 0 1000 Output Impedance vs Frequency PHASE MARGIN (DEGREES) GAIN BANDWIDTH PRODUCT (MHz) VS = ±5V RL = 1k TA = –55°C, 25°C, 125°C 60 LT1193 • TPC10 Gain Bandwidth Product and Unity Gain Phase Margin vs Temperature 70 70 50 0 COMMON MODE REJECTION RATIO (dB) PHASE PHASE MARGIN (DEGREES) 80 VOLTAGE GAIN (dB) 20k 100 OPEN-LOOP VOLTAGE GAIN (V/V) 100 Gain Bandwidth Product vs Supply Voltage GAIN BANDWIDTH PRODUCT (MHz) Gain, Phase vs Frequency 90 80 4 2 0 –2 –VOUT, –55°C, 25°C, 125°C –4 –6 –8 70 –50 –10 –25 50 0 25 75 TEMPERATURE (°C) 100 125 LT1193 • TPC17 0 2 8 4 6 ±V SUPPLY VOLTAGE (V) 10 LT1193 • TPC18 1193fb 6 LT1193 U W TYPICAL PERFOR A CE CHARACTERISTICS Output Voltage Step vs Settling Time, AV = 2 Slew Rate vs Temperature VS = ± 5V 900 3 TA = –55°C 800 4 OUTPUT VOLTAGE STEP (V) 5 – SLEW RATE SLEW RATE (V/µs) OUTPUT VOLTAGE SWING (V) Output Voltage Swing vs Load Resistance TA = 25°C 1 TA = 125°C –1 TA = 125°C –3 TA = –55°C, 25°C –5 10 100 LOAD RESISTANCE (Ω) 1000 700 600 +SLEW RATE 500 VS = ±5V 400 TA = 25°C RL = 1k VO = ±2V 300 –50 –25 0 25 50 75 TEMPERATURE (°C) LT1193 • TPC19 Large-Signal Transient Response VS = ±5V TA = 25°C RL = 1k 2 10mV 0 –2 10mV –4 100 125 40 LT1193 • TPC20 Small-Signal Transient Response 60 70 80 SETTLING TIME (ns) 90 100 LT1193 • TPC21 Small-Signal Transient Response LT1193 • TPC23 LT1193 • TPC22 AV = –10, SMALL-SIGNAL RISE TIME = 43ns AV = 2, RL = 150Ω, RFB = 300Ω, RG = 300Ω 50 LT1193 • TPC24 AV = 2, RFB = 300Ω, RG = 300Ω, OVERSHOOT = 25%, RISE TIME = 4.7ns U W U U 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 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 U W U U APPLICATIO S I FOR ATIO SHDN VIN 3 2 5 SHDN V+ 7 + – LT1193 1 +/REF 8 –/FB 4 6 VIN VOUT 3 2 5 7 + – LT1193 1 +/REF 8 –/FB 4 V– RFB RG VIN 3 2 VOUT VOUT 1V/DIV 0V 0V VOUT 10mV/DIV R + RG AV = – FB RG RG SHDN VINDIFF 6 V– RFB R + RG AV = + FB RG 5 Settling Time Poor Bypass V+ SHDN V+ 7 + – LT1193 1 +/REF 8 –/FB 4 6 VINDIFF VOUT VIN RG 3 2 5 V+ 7 + – LT1193 1 +/REF 8 –/FB 4 V– RFB LT1192 • TA05 6 SETTLING TIME TO 10mV, AV = 2 SUPPLY BYPASS CAPACITORS = 0.1µF VOUT Settling Time Good Bypass V– RFB R + RG VO = (VINDIFF + VIN) FB RG RG VO = (R R+ R ( V FB G G INDIFF – ( RR ( V FB G IN LT1193 • TA03 VOUT 1V/DIV 0V No Supply Bypass Capacitors 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 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. 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 8 LT1193 U W U U APPLICATIO S I FOR ATIO Small-Signal Transient Response Closed-Loop Voltage Gain vs Frequency CLOSED-LOOP VOLTAGE GAIN (dB) 25 VS = ±5V TA = 25°C AV = 10 AV = 5 15 AV = 3 AV = 2 5 –5 100k 1M 10M FREQUENCY (Hz) 100M LT1193 • TA10 AV = 2 WITH 8pF FEEDBACK CAPACITOR RISE TIME = 3.75ns, RFB = 1k, RG = 1k LT1193 • TA07 Closed-Loop Voltage Gain vs Frequency 8 VS = ±5V TA = 25°C AV = 2 RFB = 300Ω RG = 300Ω Double Terminated Cable Driver 5V 3 + 7 2 – LT1193 1 CFB = 0pF CFB = 5pF 8 6 RG CFB = 10pF CFB = 15pF 4 + – 75Ω 6 4 –5V CABLE 75Ω RFB CFB 2 Closed-Loop Voltage Gain vs Frequency 0 100k 8 1M 10M FREQUENCY (Hz) 100M LT1193 • TA08 Small-Signal Transient Response CLOSED LOOP VOLTAGE GAIN (dB) CLOSED-LOOP VOLTAGE GAIN (dB) 10 6 4 2 AV = 2 RFB = 300Ω RG = 100Ω CFB = 0pF 0 AV = 1 RFB = 300Ω RG = 300Ω CFB = 10pF –2 –4 –6 100k 1M 10M 100M FREQUENCY (Hz) LT1193 • TA11 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. 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 U W U U 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. 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 Output Shutdown tON = 300ns tOFF = 200ns LT1193 • TA14 AV = 2, IN DEMO BOARD, CL = 30pF, RFB = 1k, RG = 1k LT1193 • TA12 1MHz SINE WAVE GATED OFF WITH SHUTDOWN PIN, AV = 3, RFB = 1k, RG = 500Ω Driving Capacitive Load 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 AV = 2, IN DEMO BOARD, CL = 30pF WITH 10Ω ISOLATING RESISTOR 1193fb 10 LT1193 U W U U APPLICATIO S I FOR ATIO Murphy Circuits 5V 3 2 1 8 + – + – 5V 3 7 LT1193 6 2 COAX 1 8 4 + – + – –5V 5V 3 7 LT1193 2 6 1 4 8 1X SCOPE PROBE –5V + – + – 7 LT1193 6 4 –5V SCOPE PROBE LT1193 • TA13 An Unterminated Cable Is a Large Capacitive Load A 1X Scope Probe Is a Large Capacitive Load A Scope Probe on the Inverting Input Reduces Phase Margin W W SI PLIFIED SCHE ATIC 7 V+ VBIAS + 3 – 2 VBIAS CM C FF +V 6 VOUT +V * 4 V– 5 SHDN 1 +/REF 8 –/FB * SUBSTRATE DIODE, DO NOT FORWARD BIAS LT1193 • TA16 1193fb 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. 11 LT1193 U PACKAGE DESCRIPTIO J8 Package 8-Lead CERDIP (Narrow .300 Inch, Hermetic) .405 (10.287) MAX (Reference LTC DWG # 05-08-1110) .300 BSC (7.62 BSC) .200 (5.080) MAX CORNER LEADS OPTION (4 PLCS) .008 – .018 (0.203 – 0.457) .015 – .060 (0.381 – 1.524) .023 – .045 (0.584 – 1.143) HALF LEAD OPTION 0° – 15° .045 – .068 (1.143 – 1.650) FULL LEAD OPTION .005 (0.127) MIN 8 NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE OR TIN PLATE LEADS .014 – .026 (0.360 – 0.660) 5 .025 (0.635) RAD TYP .220 – .310 (5.588 – 7.874) 1 .045 – .065 (1.143 – 1.651) 6 7 2 3 4 J8 0801 .125 3.175 MIN .100 (2.54) BSC OBSOLETE PACKAGE N8 Package 8-Lead PDIP (Narrow .300 Inch) (Reference LTC DWG # 05-08-1510) .300 – .325 (7.620 – 8.255) ( +.035 .325 –.015 +0.889 8.255 –0.381 .130 ± .005 (3.302 ± 0.127) .045 – .065 (1.143 – 1.651) .065 (1.651) TYP .008 – .015 (0.203 – 0.381) ) .400* (10.160) MAX 8 7 6 5 1 2 3 4 .255 ± .015* (6.477 ± 0.381) .120 (3.048) .020 MIN (0.508) MIN .018 ± .003 (0.457 ± 0.076) .100 (2.54) BSC N8 1002 NOTE: 1. DIMENSIONS ARE INCHES MILLIMETERS *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm) 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) 8 .004 – .010 (0.101 – 0.254) .053 – .069 (1.346 – 1.752) 7 6 .045 ±.005 5 .050 BSC 0°– 8° TYP .016 – .050 (0.406 – 1.270) NOTE: 1. DIMENSIONS IN .014 – .019 (0.355 – 0.483) TYP 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) .050 (1.270) BSC .150 – .157 .245 (3.810 – 3.988) MIN NOTE 3 .228 – .244 (5.791 – 6.197) 1 2 3 4 .030 ±.005 TYP .160 ±.005 SO8 0303 RECOMMENDED SOLDER PAD LAYOUT RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1194 Video Difference Amp AV = 10 Version of the LT1193 1193fb 12 Linear Technology Corporation LT/TP 0903 1K 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 1991