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LT1361/LT1362 Dual and Quad 50MHz, 800V/s Op Amps
FEATURES
s s s s s s s s s s s s s s s s
DESCRIPTIO
50MHz Gain Bandwidth 800V/s Slew Rate 5mA Maximum Supply Current per Amplifier Unity-Gain Stable C-LoadTM Op Amp Drives All Capacitive Loads 9nV/Hz Input Noise Voltage 1mV Maximum Input Offset Voltage 1A Maximum Input Bias Current 250nA Maximum Input Offset Current 13V Minimum Output Swing into 500 3.2V Minimum Output Swing into 150 4.5V/mV Minimum DC Gain, RL=1k 60ns Settling Time to 0.1%, 10V Step 0.2% Differential Gain, AV=2, RL=150 0.3 Differential Phase, AV=2, RL=150 Specified at 2.5V, 5V, and 15V
The LT1361/LT1362 are dual and quad low power high speed operational amplifiers with outstanding AC and DC performance. The amplifiers feature much lower supply current and higher slew rate than devices with comparable bandwidth. The circuit topology is a voltage feedback amplifier with matched high impedance inputs and the slewing performance of a current feedback amplifier. The high slew rate and single stage design provide excellent settling characteristics which make the circuit an ideal choice for data acquisition systems. Each output drives a 500 load to 13V with 15V supplies and a 150 load to 3.2V on 5V supplies. The amplifiers are stable with any capacitive load making them useful in buffer or cable driving applications. The LT1361/LT1362 are members of a family of fast, high performance amplifiers using this unique topology and employing Linear Technology Corporation's advanced bipolar complementary processing. For a single amplifier version of the LT1361/LT1362 see the LT1360 data sheet. For higher bandwidth devices with higher supply currents see the LT1363 through LT1365 data sheets. For lower supply current amplifiers see the LT1354 to LT1359 data sheets. Singles, duals, and quads of each amplifier are available.
, LTC and LT are registered trademarks of Linear Technology Corporation. C-Load is a trademark of Linear Technology Corporation
APPLICATIO S
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Wideband Amplifiers Buffers Active Filters Video and RF Amplification Cable Drivers Data Acquisition Systems
TYPICAL APPLICATIO
2
Cable Driver Frequency Response
AV = -1 Large-Signal Response
0
GAIN (dB)
-2
IN
VS = 15V VS = 10V VS = 2.5V VS = 5V
+ 1/2 LT1361 - 510
510 OUT 75
-4
75
-6
-8 1 10 FREQUENCY (MHz) 100
1361/1362 TA02
1361/1362 TA01
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1
LT1361/LT1362
ABSOLUTE MAXIMUM RATINGS
Total Supply Voltage (V + to V -) ............................... 36V Differential Input Voltage (Transient Only) (Note 2)................................... 10V Input Voltage ............................................................ VS Output Short-Circuit Duration (Note 3) ............ Indefinite
PACKAGE/ORDER INFORMATION
TOP VIEW OUT A -IN A +IN A V- 1 2 A 3 4 N8 PACKAGE 8-LEAD PDIP B 6 5 -IN B +IN B 8 7 V+ OUT B
ORDER PART NUMBER LT1361CN8
TJMAX = 150C, JA = 130C/ W
TOP VIEW
OUT A
1 2 3 4 5 6 7 B C A D
14 OUT D 13 -IN D 12 +IN D 11 V - 10 +IN C 9 8
-IN C
OUT C
ORDER PART NUMBER LT1362CN
-IN A +IN A V+ +IN B -IN B
OUT B
N PACKAGE 14-LEAD PDIP
TJMAX = 150C, JA = 110C/ W
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
SYMBOL VOS PARAMETER Input Offset Voltage CONDITIONS (Note 4)
TA = 25C, VCM = 0V unless otherwise noted.
VSUPPLY 15V 5V 2.5V 2.5V to 15V 2.5V to 15V MIN TYP 0.3 0.3 0.4 80 0.3 9 0.9 20 50 5 3 MAX 1.0 1.0 1.2 250 1.0 UNITS mV mV mV nA A nV/Hz pA/Hz M M pF
IOS IB en in RIN CIN
Input Offset Current Input Bias Current Input Noise Voltage Input Noise Current Input Resistance Input Resistance Input Capacitance f = 10kHz f = 10kHz VCM = 12V Differential
2
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(Note 1)
Operating Temperature Range (Note 8) ...-40C to 85C Specified Temperature Range (Note 9) ....-40C to 85C Maximum Junction Temperature (See Below) Plastic Package ................................................ 150C Storage Temperature Range ..................-65C to 150C Lead Temperature (Soldering, 10 sec).................. 300C
TOP VIEW OUT A -IN A +IN A V- 1 2 A 3 4 S8 PACKAGE 8-LEAD PLASTIC SO B 6 5 -IN B +IN B 8 7 V+ OUT B
ORDER PART NUMBER LT1361CS8 S8 PART MARKING 1361 ORDER PART NUMBER LT1362CS
TJMAX = 150C, JA = 190C/ W
TOP VIEW
OUT A
1 2 3 4 5 6 7 8 B C A D
16 OUT D 15 -IN D 14 +IN D 13 V - 12 +IN C 11 -IN C 10 OUT C 9
NC
-IN A +IN A V+ +IN B -IN B
OUT B NC
S PACKAGE 16-LEAD PLASTIC SO
TJMAX = 150C, JA = 150C/ W
2.5V to 15V 2.5V to 15V 15V 15V 15V
LT1361/LT1362
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER Input Voltage Range
+
TA = 25C, VCM = 0V unless otherwise noted.
VSUPPLY 15V 5V 2.5V 15V 5V 2.5V MIN 12.0 2.5 0.5 TYP 13.4 3.4 1.1 -13.2 -3.2 -0.9 86 79 68 93 15V 15V 5V 5V 2.5V 15V 15V 5V 5V 2.5V 15V 5V 15V 15V 5V 15V 5V 15V 5V 2.5V 15V 5V 15V 5V 15V 5V 15V 15V 5V 15V 5V 15V 5V 15V 5V 15V 5V 15V 15V 15V 5V 100 35 25 4.5 3.0 3.0 1.5 2.5 13.5 13.0 3.5 3.2 1.3 26 21 40 600 250 92 84 74 105 9.0 6.5 6.4 4.2 5.2 13.9 13.6 4.0 3.8 1.7 34 29 54 800 350 12.7 18.6 50 37 32 3.1 4.3 35 27 5.2 6.4 60 90 65 0.20 0.20 0.04 0.02 0.40 0.30 0.07 0.26 1.4 113 4.0 3.8 5.0 4.8 -12.0 -2.5 -0.5 MAX UNITS V V V V V V dB dB dB dB V/mV V/mV V/mV V/mV V/mV V V V V V mA mA mA V/s V/s MHz MHz MHz MHz MHz ns ns % % ns ns ns ns ns % % % % Deg Deg Deg Deg dB mA mA
CONDITIONS
Input Voltage Range -
CMRR
Common Mode Rejection Ratio
VCM = 12V VCM = 2.5V VCM = 0.5V VS = 2.5V to 15V VOUT = 12V, RL = 1k VOUT = 10V, RL = 500 VOUT = 2.5V, RL = 500 VOUT = 2.5V, RL = 150 VOUT = 1V, RL = 500 RL = 1k, VIN = 40mV RL = 500, VIN = 40mV RL = 500, VIN = 40mV RL = 150, VIN = 40mV RL = 500, VIN = 40mV VOUT = 13V VOUT = 3.2V VOUT = 0V, VIN = 3V AV = - 2, (Note 5) 10V Peak, (Note 6) 3V Peak, (Note 6) f = 200kHz
15V 5V 2.5V
PSRR AVOL
Power Supply Rejection Ratio Large-Signal Voltage Gain
VOUT
Output Swing
IOUT ISC SR
Output Current Short-Circuit Current Slew Rate Full Power Bandwidth
GBW
Gain Bandwidth
tr, tf
Rise Time, Fall Time Overshoot Propagation Delay
AV = 1, 10%-90%, 0.1V AV = 1, 0.1V 50% VIN to 50% VOUT, 0.1V 10V Step, 0.1%, AV = -1 10V Step, 0.01%, AV = -1 5V Step, 0.1%, AV = -1 f = 3.58MHz, AV = 2, RL = 150 f = 3.58MHz, AV = 2, RL = 1k
ts
Settling Time
Differential Gain
Differential Phase
f = 3.58MHz, AV = 2, RL = 150 f = 3.58MHz, AV = 2, RL = 1k
RO IS
Output Resistance Channel Separation Supply Current
AV = 1, f = 1MHz VOUT = 10V, RL = 500 Each Amplifier Each Amplifier
3
LT1361/LT1362
0C TA 70C, VCM = 0V unless otherwise noted.
SYMBOL VOS PARAMETER Input Offset Voltage
ELECTRICAL CHARACTERISTICS
CONDITIONS (Note 4)
The q denotes the specifications which apply over the temperature range
VSUPPLY 15V 5V 2.5V 2.5V to 15V 2.5V to 15V 2.5V to 15V
q q q q q q q q q q
MIN
TYP
MAX 1.5 1.5 1.7
UNITS mV mV mV V/C nA A dB dB dB dB V/mV V/mV V/mV V/mV V/mV V V V V V mA mA mA V/s V/s MHz MHz dB
Input VOS Drift IOS IB CMRR Input Offset Current Input Bias Current Common Mode Rejection Ratio
(Note 7)
9
12 350 1.5
VCM = 12V VCM = 2.5V VCM = 0.5V VS = 2.5V to 15V VOUT = 12V, RL = 1k VOUT = 10V, RL = 500 VOUT = 2.5V, RL = 500 VOUT = 2.5V, RL = 150 VOUT = 1V, RL = 500 RL = 1k, VIN = 40mV RL = 500, VIN = 40mV RL = 500, VIN = 40mV RL = 150, VIN = 40mV RL = 500, VIN = 40mV VOUT = 12.8V VOUT = 3.1V VOUT = 0V, VIN = 3V AV = - 2, (Note 5) f = 200kHz VOUT = 10V, RL = 500 Each Amplifier Each Amplifier
15V 5V 2.5V 15V 15V 5V 5V 2.5V 15V 15V 5V 5V 2.5V 15V 5V 15V 15V 5V 15V 5V 15V 15V 5V
84 77 66 91 3.6 2.4 2.4 1.0 2.0 13.4 12.8 3.4 3.1 1.2 25 20 32 475 185 31 22 98 5.8 5.6
PSRR AVOL
Power Supply Rejection Ratio Large-Signal Voltage Gain
q q q q q q q q q q q q q q q q q q q q
VOUT
Output Swing
IOUT ISC SR GBW
Output Current Short-Circuit Current Slew Rate Gain Bandwidth Channel Separation
IS
Supply Current
mA mA
The q denotes the specifications which apply over the temperature range - 40C TA 85C, VCM = 0V unless otherwise noted. (Note 9)
SYMBOL VOS PARAMETER Input Offset Voltage CONDITIONS (Note 4) VSUPPLY 15V 5V 2.5V 2.5V to 15V 2.5V to 15V 2.5V to 15V VCM = 12V VCM = 2.5V VCM = 0.5V VS = 2.5V to 15V VOUT = 12V, RL = 1k VOUT = 10V, RL = 500 VOUT = 2.5V, RL = 500 VOUT = 2.5V, RL = 150 VOUT = 1V, RL = 500 15V 15V 5V 5V 2.5V 15V 5V 2.5V
q q q q q q q q q q q q q q q
MIN
TYP
MAX 2.0 2.0 2.2
UNITS mV mV mV V/C nA A dB dB dB dB V/mV V/mV V/mV V/mV V/mV
Input VOS Drift IOS IB CMRR Input Offset Current Input Bias Current Common Mode Rejection Ratio
(Note 7)
9
12 400 1.8
84 77 66 90 2.5 1.5 1.5 0.6 1.3
PSRR AVOL
Power Supply Rejection Ratio Large-Signal Voltage Gain
4
LT1361/LT1362
ELECTRICAL CHARACTERISTICS
SYMBOL VOUT PARAMETER Output Swing
The q denotes the specifications which apply over the temperature range - 40C TA 85C, VCM = 0V unless otherwise noted. (Note 9)
CONDITIONS RL = 1k, VIN = 40mV RL = 500, VIN = 40mV RL = 500, VIN = 40mV RL = 150, VIN = 40mV RL = 500, VIN = 40mV VOUT = 12.0V VOUT = 3.0V VOUT = 0V, VIN = 3V AV = - 2, (Note 5) f = 200kHz VOUT = 10V, RL = 500 Each Amplifier Each Amplifier VSUPPLY 15V 15V 5V 5V 2.5V 15V 5V 15V 15V 5V 15V 5V 15V 15V 5V
q q q q q q q q q q q q q q q
MIN 13.4 12.0 3.4 3.0 1.2 24 20 30 450 175 30 20 98
TYP
MAX
UNITS V V V V V mA mA mA V/s V/s MHz MHz dB
IOUT ISC SR GBW
Output Current Short-Circuit Current Slew Rate Gain Bandwidth Channel Separation
IS
Supply Current
6.0 5.8
mA mA
Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: Differential inputs of 10V are appropriate for transient operation only, such as during slewing. Large, sustained differential inputs will cause excessive power dissipation and may damage the part. See Input Considerations in the Applications Information section of this data sheet for more details. Note 3: A heat sink may be required to keep the junction temperature below absolute maximum when the output is shorted indefinitely. Note 4: Input offset voltage is pulse tested and is exclusive of warm-up drift. Note 5: Slew rate is measured between 10V on the output with 6V input for 15V supplies and 1V on the output with 1.75V input for 5V supplies.
Note 6: Full power bandwidth is calculated from the slew rate measurement: FPBW = SR/2VP. Note 7: This parameter is not 100% tested. Note 8: The LT1361C/LT1362C are guaranteed functional over the operating temperature range of -40C to 85C. Note 9: The LT1361C/LT1362C are guaranteed to meet specified performance from 0C to 70C. The LT1361C/LT1362C are designed, characterized and expected to meet specified performance from - 40C to 85C, but are not tested or QA sampled at these temperatures. For guaranteed I-grade parts, consult the factory.
TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current vs Supply Voltage and Temperature
6
COMMON MODE RANGE (V)
125C 4 25C
-1.5 -2.0
INPUT BIAS CURRENT (A)
5
SUPPLY CURRENT (mA)
3 - 55C 2
1 0 5 10 15 SUPPLY VOLTAGE (V) 20
1361/1362 G01
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Input Common Mode Range vs Supply Voltage
V+ -0.5 -1.0 TA = 25C VOS < 1mV
0.6 0.5 0.4 0.3 0.2 0.1
Input Bias Current vs Input Common Mode Voltage
VS = 15V TA = 25C IB+ + IB- IB = -------- 2
2.0 1.5 1.0 0.5 V- 0 5 10 15 SUPPLY VOLTAGE (V) 20
1361/1362 G02
0 -15
-10 -5 0 5 10 INPUT COMMON MODE VOLTAGE (V)
15
1361/1362 G03
5
LT1361/LT1362 TYPICAL PERFORMANCE CHARACTERISTICS
Input Bias Current vs Temperature
0.7 0.6
INPUT BIAS CURRENT (A)
INPUT VOLTAGE NOISE (nV/Hz)
VS = 15V IB+ + IB- IB = -------- 2
0.5 0.4 0.3 0.2 0.1 0 -50
OPEN-LOOP GAIN (dB)
-25
0 25 50 75 TEMPERATURE (C)
Open-Loop Gain vs Temperature
81 80 79 VS = 15V VO = 12V RL = 1k
OUTPUT VOLTAGE SWING (V)
OUTPUT VOLTAGE SWING (V)
OPEN-LOOP GAIN (dB)
78 77 76 75 74 73 72 - 50 -25 0 25 50 75 TEMPERATURE (C) 100 125
Output Short-Circuit Current vs Temperature
70
OUTPUT SHORT-CIRCUIT CURRENT (mA)
VS = 5V
65 60 55 SOURCE 50 SINK 45 40 35 -50
OUTPUT STEP (V)
2 0 -2 -4 10mV -6 -8 -10 1mV
OUTPUT STEP (V)
-25
0 25 50 75 TEMPERATURE (C)
6
UW
100
1361/1362 G04
1361/1362 G07
Input Noise Spectral Density
100 VS = 15V TA = 25C AV = 101 RS = 100k in en 1 10
INPUT CURRENT NOISE (pA/Hz)
85
Open-Loop Gain vs Resistive Load
TA = 25C 80 VS = 5V VS = 15V
75
10
70
65
1 125 10 100 1k 10k FREQUENCY (Hz)
0.1 100k
1361/1362 G05
60 10 100 1k LOAD RESISTANCE () 10k
1361/1362 G06
Output Voltage Swing vs Supply Voltage
V+ TA = 25C -1 -2 -3 3 2 1 V- 0 5 10 15 SUPPLY VOLTAGE (V) 20
1361/1362 G08
Output Voltage Swing vs Load Current
V+
RL = 1k
-0.5 -1.0 -1.5 -2.0
VS = 5V VIN = 100mV
85C 25C -40C
RL = 500
2.0 1.5 1.0 25C
-40C
RL = 500 RL = 1k
85C 0.5 V- -50 -40 -30 -20 -10 0 10 20 30 40 50 OUTPUT CURRENT (mA)
1361/1362 G09
Settling Time vs Output Step (Noninverting)
10 8 6 4 VS = 15V AV = 1 RL = 1k 10mV 1mV 10 8 6 4 2 0 -2 -4
Settling Time vs Output Step (Inverting)
VS = 15V AV = -1 RF = 1k CF = 3pF
10mV 1mV
10mV -6 -8 -10 100 0 20 1mV
100
125
0
20
40 60 80 SETTLING TIME (ns)
40 60 80 SETTLING TIME (ns)
100
1361/1362 G10
1361/1362 G11
1361/1362 G12
LT1361/LT1362 TYPICAL PERFORMANCE CHARACTERISTICS
Output Impedance vs Frequency
100 AV = 10 70 60 50 GAIN AV = 1 1
GAIN (dB)
OUTPUT IMPEDANCE ()
10
AV = 100
40 30 20 10 VS = 5V VS = 5V
60 40 20 0 TA = 25C AV = -1 RF = RG = 1k 100k 1M 10M FREQUENCY (Hz) 100M
1361/1362 G14
CROSSTALK (dB)
0.1 VS = 15V TA = 25C 0.01 10k 100k 1M 10M FREQUENCY (Hz) 100M
1361/1362 G13
Gain Bandwidth and Phase Margin vs Temperature
80 PHASE MARGIN VS = 5V PHASE MARGIN VS = 15V 60 GAIN BANDWIDTH VS = 15V GAIN BANDWIDTH VS = 5V 50 45 40 PHASE MARGIN (DEG) 35 30 25 20 15 10 5 30 -50 -25 0 25 50 75 TEMPERATURE (C) 100 0 125
5 4 3 2 GAIN (dB) 1 0 -1 -2 -3 -4
VOLTAGE MAGNITUDE (dB)
GAIN BANDWIDTH (MHz)
70
50
40
Gain Bandwidth and Phase Margin vs Supply Voltage
80 TA = 25C 70
GAIN BANDWIDTH (MHz)
48 46
PHASE MARGIN (DEG)
COMMON-MODE REJECTION RATIO (dB)
POWER SUPPLY REJECTION RATIO (dB)
PHASE MARGIN
60
50
40
GAIN BANDWIDTH
30 0 5 10 15 SUPPLY VOLTAGE (V) 20
1361/1362 G15
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1361/1362 G16
Gain and Phase vs Frequency
120 PHASE VS = 15V VS = 15V 100
PHASE (DEG)
Crosstalk vs Frequency
-20 -30 -40 -50 -60 -70 -80 -90 VS = 15V RL = 1k VS = 5V RL = 500 TA = 25C AV = 1 VIN = 0dBm
80
-100 -110 -120 100k
0 -10 10k
1M 10M FREQUENCY (Hz)
100M
1361/1362 G21
Frequency Response vs Supply Voltage (AV = 1)
12 TA = 25C AV = 1 RL = 1k 15V 10 8 6 4 2 0 -2 -4 -6 100M
1361/1362 G17
Frequency Response vs Capacitive Load
VS = 15V TA = 25C AV = -1 C = 1000pF C = 500pF C = 100pF C = 50pF C=0
5V
2.5V 1M 10M FREQUENCY (Hz)
-5 100k
-8 1M
10M FREQUENCY (Hz)
100M
1361/1362 G18
Power Supply Rejection Ratio vs Frequency
50
100 +PSRR 80 - PSRR VS = 15V TA = 25C
120 100 80 60 40 20 0
Common Mode Rejection Ratio vs Frequency
VS = 15V TA = 25C
44 42 40 38 36 34 32 30
60
40
20
0 100
1k
10k 100k 1M FREQUENCY (Hz)
10M
100M
1k
10k
100k 1M FREQUENCY (Hz)
10M
100M
1361/1362 G19
1361/1362 G20
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LT1361/LT1362 TYPICAL PERFORMANCE CHARACTERISTICS
Slew Rate vs Supply Voltage
2000 1800 1600
SLEW RATE (V/s)
SLEW RATE (V/s)
1200 1000 800 600 400 200 0 0 5 10 SUPPLY VOLTAGE (V) 15
1361/1362 G22
700 600 500 400 300 200 -50 -25 0 25 50 75 TEMPERATURE (C) 100 125 VS = 5V VS = 15V
SLEW RATE (V/s)
1400
TA = 25C AV = -1 RF = RG = 1k SR+ + SR - SR = ---------- 2
Total Harmonic Distortion vs Frequency
0.01 30 TA = 25C VO = 3VRMS RL = 500
TOTAL HARMONIC DISTORTION (%)
OUTPUT VOLTAGE (VP-P)
20 15 10 5 VS = 15V RL = 1k AV = 1, 1% MAX DISTORTION AV = -1, 2% MAX DISTORTION 1M FREQUENCY (Hz) 10M
1361/1362 G26
OUTPUT VOLTAGE (VP-P)
0.001
AV = -1 AV = 1
0.0001 10 100 1k 10k FREQUENCY (Hz) 100k
1361/1362 G25
2nd and 3rd Harmonic Distortion vs Frequency
-30 -40 -50 VS = 15V VO = 2VP-P RL = 500 AV = 2
HARMONIC DISTORTION (dB)
3RD HARMONIC
OVERSHOOT (%)
DIFFERENTIAL PHASE (DEG)
-60 -70 2ND HARMONIC -80 -90 100k 200k
400k 1M 2M FREQUENCY (Hz)
8
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4M
1361/1362 G28
Slew Rate vs Temperature
1000 AV = -2 900 800 SR + + SR - SR = ---------- 2 2000 1800 1600 1400 1200 1000 800 600 400 200 0
Slew Rate vs Input Level
TA = 25C VS = 15V AV = -1 RF = RG = 1k SR + + SR - SR = ---------- 2
0
2
4
6 8 10 12 14 16 18 INPUT LEVEL (VP-P)
20
1361/1362 G23
1361/1362 G24
Undistorted Output Swing vs Frequency (15V)
10 AV = -1 25 8
Undistorted Output Swing vs Frequency (5V)
AV = -1
6
AV = 1
AV = 1
4
2
VS = 5V RL = 1k 2% MAX DISTORTION 1M FREQUENCY (Hz) 10M
1361/1362 G27
0 100k
0 100k
Differential Gain and Phase vs Supply Voltage
0.50
Capacitive Load Handling
100 TA = 25C VS = 15V
DIFFERENTIAL GAIN (%)
0.25 DIFFERENTIAL GAIN 0.40 0
AV = -1 50
0.36 DIFFERENTIAL PHASE 0.32 AV = 2 RL = 150 TA = 25C 5 10 SUPPLY VOLTAGE (V) 15
1361/1362 G29
AV = 1 0 10p
0.28
10M
100p
1000p 0.01 0.1 CAPACITIVE LOAD (F)
1
1361/1362 G30
LT1361/LT1362 TYPICAL PERFORMANCE CHARACTERISTICS
Small-Signal Transient (AV = 1) Small-Signal Transient (AV = -1) Small-Signal Transient (AV = -1, CL = 500pF)
1361/1362 TA31
Large-Signal Transient (AV = 1)
1361/1362 TA34
APPLICATIONS INFORMATION
Layout and Passive Components The LT1361/LT1362 amplifiers are easy to use and tolerant of less than ideal layouts. For maximum performance (for example, fast 0.01% settling) use a ground plane, short lead lengths, and RF-quality bypass capacitors (0.01F to 0.1F). For high drive current applications use low ESR bypass capacitors (1F to 10F tantalum). The parallel combination of the feedback resistor and gain setting resistor on the inverting input combine with the input capacitance to form a pole which can cause peaking or oscillations. If feedback resistors greater than 5k are used, a parallel capacitor of value CF > RG x CIN/RF should be used to cancel the input pole and optimize dynamic performance. For unity-gain applications where a large feedback resistor is used, CF should be greater than or equal to CIN. Input Considerations Each of the LT1361/LT1362 inputs is the base of an NPN and a PNP transistor whose base currents are of opposite polarity and provide first-order bias current cancellation. Because of variation in the matching of NPN and PNP beta, the polarity of the input bias current can be positive or negative. The offset current does not depend on NPN/PNP beta matching and is well controlled. The use of balanced source resistance at each input is recommended for applications where DC accuracy must be maximized. The inputs can withstand transient differential input voltages up to 10V without damage and need no clamping or source resistance for protection. Differential inputs, however, generate large supply currents (tens of mA) as required for high slew rates. If the device is used with sustained differential inputs, the average supply current will increase, excessive power dissipation will result and the part may be damaged. The part should not be used as a comparator, peak detector or other open-loop applica-
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1361/1362 TA32
1361/1362 TA33
Large-Signal Transient (AV = -1)
Large-Signal Transient (AV = 1, CL = 10,000pF)
1361/1362 TA35
1361/1362 TA36
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LT1361/LT1362
APPLICATIONS INFORMATION
tion with large, sustained differential inputs. Under normal, closed-loop operation, an increase of power dissipation is only noticeable in applications with large slewing outputs and is proportional to the magnitude of the differential input voltage and the percent of the time that the inputs are apart. Measure the average supply current for the application in order to calculate the power dissipation. Capacitive Loading The LT1361/LT1362 are stable with any capacitive load. This is accomplished by sensing the load induced output pole and adding compensation at the amplifier gain node. As the capacitive load increases, both the bandwidth and phase margin decrease so there will be peaking in the frequency domain and in the transient response as shown in the typical performance curves. The photo of the small signal response with 500pF load shows 60% peaking. The large signal response shows the output slew rate being limited to 5V/s by the short-circuit current. Coaxial cable can be driven directly, but for best pulse fidelity a resistor of value equal to the characteristic impedance of the cable (i.e., 75) should be placed in series with the output. The other end of the cable should be terminated with the same value resistor to ground. Circuit Operation The LT1361/LT1362 circuit topology is a true voltage feedback amplifier that has the slewing behavior of a current feedback amplifier. The operation of the circuit can be understood by referring to the simplified schematic. The inputs are buffered by complementary NPN and PNP emitter followers which drive a 500 resistor. The input voltage appears across the resistor generating currents which are mirrored into the high impedance node. Complementary followers form an output stage which buffers the gain node from the load. The bandwidth is set by the input resistor and the capacitance on the high impedance node. The slew rate is determined by the current available to charge the gain node capacitance. This current is the differential input voltage divided by R1, so the slew rate is proportional to the input. Highest slew rates are therefore seen in the lowest gain configurations. For example, a 10V output step in a gain of 10 has only a 1V input step, whereas the same output step in unity gain has a 10 times greater input step. The curve of Slew Rate vs Input Level illustrates this relationship. The LT1361/LT1362 are tested for slew rate in a gain of -2 so higher slew rates can be expected in gains of 1 and -1, and lower slew rates in higher gain configurations. The RC network across the output stage is bootstrapped when the amplifier is driving a light or moderate load and has no effect under normal operation. When driving a capacitive load (or a low value resistive load) the network is incompletely bootstrapped and adds to the compensation at the high impedance node. The added capacitance slows down the amplifier which improves the phase margin by moving the unity-gain frequency away from the pole formed by the output impedance and the capacitive load. The zero created by the RC combination adds phase to ensure that even for very large load capacitances, the total phase lag can never exceed 180 degrees (zero phase margin) and the amplifier remains stable. Power Dissipation The LT1361/LT1362 combine high speed and large output drive in small packages. Because of the wide supply voltage range, it is possible to exceed the maximum junction temperature under certain conditions. Maximum junction temperature (TJ) is calculated from the ambient temperature (TA) and power dissipation (PD) as follows: LT1361CN8: LT1361CS8: LT1362CN: LT1362CS: TJ = TA + (PD x 130C/W) TJ = TA + (PD x 190C/W) TJ = TA + (PD x 110C/W) TJ = TA + (PD x 150C/W)
10
U
W
U
U
Worst case power dissipation occurs at the maximum supply current and when the output voltage is at 1/2 of either supply voltage (or the maximum swing if less than 1/2 supply voltage). For each amplifier PDMAX is: PDMAX = (V+ - V-)(ISMAX) + (V+/2)2/RL Example: LT1362 in S16 at 70C, VS = 5V, RL = 100 PDMAX = (10V)(5.6mA) + (2.5V)2/100 = 119mW TJMAX = 70C + (4 x 119mW)(150C/W) = 141C
LT1361/LT1362
SI PLIFIED SCHE ATIC
V+
-IN C
V-
1361/1362 SS01
PACKAGE DESCRIPTION
0.300 - 0.325 (7.620 - 8.255)
0.009 - 0.015 (0.229 - 0.381)
0.065 (1.651) TYP 0.125 (3.175) 0.020 MIN (0.508) MIN 0.018 0.003 (0.457 0.076)
(
+0.035 0.325 -0.015 +0.889 8.255 -0.381
)
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)
0.300 - 0.325 (7.620 - 8.255)
0.130 0.005 (3.302 0.127) 0.020 (0.508) MIN
0.009 - 0.015 (0.229 - 0.381) 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) +0.035 0.325 -0.015 +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.
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W
W
R1 500
+IN
RC
CC OUT
Dimension in inches (millimeters) unless otherwise noted. N8 Package 8-Lead PDIP (Narrow 0.300)
(LTC DWG # 05-08-1510)
0.400* (10.160) MAX 8 7 6 5
0.045 - 0.065 (1.143 - 1.651)
0.130 0.005 (3.302 0.127)
0.255 0.015* (6.477 0.381)
1
2
3
4
0.100 (2.54) BSC
N8 1098
N Package 14-Lead PDIP (Narrow 0.300)
(LTC DWG # 05-08-1510)
0.770* (19.558) MAX 14 13 12 11 10 9 8
0.045 - 0.065 (1.143 - 1.651)
0.065 (1.651) TYP 0.018 0.003 (0.457 0.076)
0.255 0.015* (6.477 0.381)
1
2
3
4
5
6
7
N14 1098
11
LT1361/LT1362
TYPICAL APPLICATIONS
Two Op Amp Instrumentation Amplifier
R5 220 R1 10k R2 1k
909 2.67k 220pF
-
1/2 LT1361
R3 1k
-
VIN
+
+
R4 1 R2 R3 R2 + R3 GAIN = 1 + + + R5 R3 2 R1 R4 TRIM R5 FOR GAIN TRIM R1 FOR COMMON-MODE REJECTION BW = 500kHz
(
) = 102

1361/1362 TA03
PACKAGE DESCRIPTION
0.010 - 0.020 x 45 (0.254 - 0.508) 0.008 - 0.010 (0.203 - 0.254) 0- 8 TYP
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
0.016 - 0.050 (0.406 - 1.270)
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
0.014 - 0.019 0.016 - 0.050 (0.355 - 0.483) (0.406 - 1.270) 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
RELATED PARTS
PART NUMBER LT1360 LT1364/LT1365 LT1358/LT1359 LT1813 DESCRIPTION 50MHz, 800V/s Op Amp Dual and Quad 70MHz, 1000V/s Op Amps Dual and Quad 25MHz, 600Vs Op Amps Dual 100MHz, 700V/s Op Amps COMMENTS Single Version of LT1361/LT1362 Faster Version of LT1361/LT1362, VOS = 1.5mV, IS = 6.3mA/Amplifier Lower Power Version of LT1361/LT1362, VOS = 0.6mV, IS = 2mA/Amplifier Low Voltage, Low Power LT1361, IS = 3mA/Amplifier
13612fa LT/TP 0400 2K REV A * 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-tech.com
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U
- +
1MHz, 4th Order Butterworth Filter
909 47pF 22pF 1.1k
R4 10k
VIN
-
1/2 LT1361
1.1k
2.21k 470pF
-
1/2 LT1361 VOUT
1/2 LT1361
VOUT
+
+
1361/1362 TA04
Dimension in inches (millimeters) unless otherwise noted.
S8 Package 8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.189 - 0.197* (4.801 - 5.004) 0.053 - 0.069 (1.346 - 1.752) 8 0.004 - 0.010 (0.101 - 0.254) 0.228 - 0.244 (5.791 - 6.197) 0.150 - 0.157** (3.810 - 3.988) 7 6 5
0.050 (1.270) BSC
1
2
3
4
SO8 1298
S Package 16-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.386 - 0.394* (9.804 - 10.008) 0.004 - 0.010 (0.101 - 0.254) 16 15 14 13 12 11 10 9
0.050 (1.270) BSC
0.228 - 0.244 (5.791 - 6.197)
0.150 - 0.157** (3.810 - 3.988)
1
2
3
4
5
6
7
8
S16 1098
(c) LINEAR TECHNOLOGY CORPORATION 1994

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