LT1360
50MHz, 800V/µs Op Amp
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DESCRIPTIO
FEATURES
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50MHz Gain Bandwidth
800V/µs Slew Rate
5mA Maximum Supply Current
9nV/√Hz Input Noise Voltage
Unity-Gain Stable
C-LoadTM Op Amp Drives All Capacitive Loads
1mV Maximum Input Offset Voltage
1µA Maximum Input Bias Current
250nA Maximum Input Offset Current
±13V Minimum Output Swing into 500Ω
±3.2V Minimum Output Swing into 150Ω
4.5V/mV Minimum DC Gain, RL=1k
60ns Settling Time to 0.1%, 10V Step
0.2% Differential Gain, AV=2, RL=150Ω
0.3° Differential Phase, AV=2, RL=150Ω
Specified at ±2.5V, ±5V, and ±15V
The LT1360 is a high speed, very high slew rate operational amplifier with excellent DC performance. The LT1360
features reduced supply current, lower input offset voltage, lower input bias current and higher DC gain than
devices with comparable bandwidth. The circuit topology
is a voltage feedback amplifier with the slewing characteristics of a current feedback amplifier. The amplifier is a
single gain stage with outstanding settling characteristics
which makes the circuit an ideal choice for data acquisition
systems. The output drives a 500Ω load to ±13V with ±15V
supplies and a 150Ω load to ±3.2V on ±5V supplies. The
amplifier is also capable of driving any capacitive load
which makes it useful in buffer or cable driver applications.
The LT1360 is a member of a family of fast, high
performance amplifiers using this unique topology and
employing Linear Technology Corporation’s advanced
bipolar complementary processing. For dual and quad
amplifier versions of the LT1360 see the LT1361/LT1362
data sheet. For 70MHz amplifiers with 6mA of supply
current per amplifier see the LT1363 and LT1364/LT1365
data sheets. For lower supply current amplifiers with
bandwidths of 12MHz and 25MHz see the LT1354
through LT1359 data sheets. Singles, duals and quads of
each amplifier are available.
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APPLICATIO S
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Wideband Amplifiers
Buffers
Active Filters
Video and RF Amplification
Cable Drivers
Data Acquisition Systems
, LTC and LT are registered trademarks of Linear Technology Corporation.
C-Load is a trademark of Linear Technology Corporation.
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TYPICAL APPLICATIO
AV = –1 Large-Signal Response
Two Op Amp Instrumentation Amplifier
R5
220Ω
R1
10k
R4
10k
R2
1k
R3
1k
–
–
LT1360
–
+
LT1360
VOUT
+
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


1360 TA02
1360 TA01
1
LT1360
W W
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W
ABSOLUTE MAXIMUM RATINGS
(Note 1)
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
Operating Temperature Range (Note 8) ...–40°C to 85°C
Specified Temperature Range (Note 9) ....–40°C to 85°C
Maximum Junction Temperature (See Below)
Plastic Package ................................................ 150°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
W
U
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PACKAGE/ORDER INFORMATION
TOP VIEW
NULL
1
8
NULL
–IN
2
7
V+
+IN
3
6
VOUT
V–
4
5
NC
ORDER PART
NUMBER
LT1360CN8
ORDER PART
NUMBER
TOP VIEW
NULL
1
8
NULL
–IN
2
7
V+
+IN
3
6
VOUT
V–
4
5
NC
N8 PACKAGE, 8-LEAD PDIP
S8 PACKAGE, 8-LEAD PLASTIC SO
TJMAX = 150°C, θJA = 130°C/ W
TJMAX = 150°C, θJA = 190°C/ W
LT1360CS8
S8 PART MARKING
1360
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
TA = 25°C, VCM = 0V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
VSUPPLY
TYP
MAX
UNITS
VOS
Input Offset Voltage
(Note 4)
±15V
±5V
±2.5V
0.3
0.3
0.4
1.0
1.0
1.2
mV
mV
mV
IOS
Input Offset Current
±2.5V to ±15V
80
250
nA
IB
Input Bias Current
±2.5V to ±15V
0.3
1.0
en
Input Noise Voltage
f = 10kHz
±2.5V to ±15V
9
nV/√Hz
in
Input Noise Current
f = 10kHz
±2.5V to ±15V
0.9
pA/√Hz
RIN
Input Resistance
VCM = ±12V
±15V
50
MΩ
Input Resistance
Differential
±15V
5
MΩ
±15V
3
pF
13.4
3.4
1.1
V
V
V
CIN
Input Capacitance
+
±15V
±5V
±2.5V
Input Voltage Range –
±15V
±5V
±2.5V
Input Voltage Range
CMRR
Common Mode Rejection Ratio
VCM = ±12V
VCM = ±2.5V
VCM = ±0.5V
PSRR
Power Supply Rejection Ratio
VS = ±2.5V to ±15V
2
±15V
±5V
±2.5V
MIN
20
12.0
2.5
0.5
–13.2
–3.2
–0.9
–12.0
–2.5
–0.5
µA
V
V
V
86
79
68
92
84
74
dB
dB
dB
93
105
dB
LT1360
ELECTRICAL CHARACTERISTICS
TA = 25°C, VCM = 0V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
VSUPPLY
MIN
TYP
AVOL
Large-Signal Voltage Gain
VOUT = ±12V, RL = 1k
VOUT = ±10V, RL = 500Ω
VOUT = ±2.5V, RL = 500Ω
VOUT = ±2.5V, RL = 150Ω
VOUT = ±1V, RL = 500Ω
VOUT
Output Swing
IOUT
Output Current
MAX
UNITS
±15V
±15V
±5V
±5V
±2.5V
4.5
3.0
3.0
1.5
2.5
9.0
6.5
6.4
4.2
5.2
V/mV
V/mV
V/mV
V/mV
V/mV
RL = 1k, VIN = ±40mV
RL = 500Ω, VIN = ±40mV
RL = 500Ω, VIN = ±40mV
RL = 150Ω, VIN = ±40mV
RL = 500Ω, VIN = ±40mV
±15V
±15V
±5V
±5V
±2.5V
13.5
13.0
3.5
3.2
1.3
13.9
13.6
4.0
3.8
1.7
±V
±V
±V
±V
±V
VOUT = ±13V
VOUT = ±3.2V
±15V
±5V
26
21
34
29
mA
mA
ISC
Short-Circuit Current
VOUT = 0V, VIN = ±3V
±15V
40
54
mA
SR
Slew Rate
AV = –2, (Note 5)
±15V
±5V
600
250
800
350
V/µs
V/µs
Full Power Bandwidth
10V Peak, (Note 6)
3V Peak, (Note 6)
±15V
±5V
12.7
18.6
MHz
MHz
GBW
Gain Bandwidth
f = 1MHz
±15V
±5V
±2.5V
50
37
32
MHz
MHz
MHz
tr , tf
Rise Time, Fall Time
AV = 1, 10%-90%, 0.1V
±15V
±5V
3.1
4.3
ns
ns
Overshoot
AV = 1, 0.1V
±15V
±5V
35
27
%
%
Propagation Delay
50% VIN to 50% VOUT, 0.1V
±15V
±5V
5.2
6.4
ns
ns
Settling Time
10V Step, 0.1%, AV = –1
10V Step, 0.01%, AV = –1
5V Step, 0.1%, AV = –1
±15V
±15V
±5V
60
90
65
ns
ns
ns
Differential Gain
f = 3.58MHz, AV = 2, RL = 150Ω
±15V
±5V
±15V
±5V
0.20
0.20
0.04
0.02
%
%
%
%
±15V
±5V
±15V
±5V
0.40
0.30
0.07
0.26
Deg
Deg
Deg
Deg
±15V
1.4
±15V
±5V
4.0
3.8
ts
f = 3.58MHz, AV = 2, RL = 1k
Differential Phase
f = 3.58MHz, AV = 2, RL = 150Ω
f = 3.58MHz, AV = 2, RL = 1k
RO
Output Resistance
IS
Supply Current
AV = 1, f = 1MHz
Ω
5.0
4.8
mA
mA
3
LT1360
ELECTRICAL CHARACTERISTICS
0°C ≤ TA ≤ 70°C, VCM = 0V unless otherwise noted.
The ● denotes the specifications which apply over the temperature range
SYMBOL
PARAMETER
CONDITIONS
VSUPPLY
VOS
Input Offset Voltage
(Note 4)
±15V
±5V
±2.5V
●
●
●
MIN
Input VOS Drift
(Note 7)
±2.5V to ±15V
●
TYP
9
MAX
UNITS
1.5
1.5
1.7
mV
mV
mV
12
µV/°C
IOS
Input Offset Current
±2.5V to ±15V
●
350
nA
IB
Input Bias Current
±2.5V to ±15V
●
1.5
µA
CMRR
Common Mode Rejection Ratio
±15V
±5V
±2.5V
●
●
●
PSRR
Power Supply Rejection Ratio
VS = ±2.5V to ±15V
●
91
dB
AVOL
Large-Signal Voltage Gain
VOUT = ±12V, RL = 1k
VOUT = ±10V, RL = 500Ω
VOUT = ±2.5V, RL = 500Ω
VOUT = ±2.5V, RL = 150Ω
VOUT = ±1V, RL = 500Ω
±15V
±15V
±5V
±5V
±2.5V
●
●
●
●
●
3.6
2.4
2.4
1.0
2.0
V/mV
V/mV
V/mV
V/mV
V/mV
VOUT
Output Swing
RL = 1k, VIN = ±40mV
RL = 500Ω, VIN = ±40mV
RL = 500Ω, VIN = ±40mV
RL = 150Ω, VIN = ±40mV
RL = 500Ω, VIN = ±40mV
±15V
±15V
±5V
±5V
±2.5V
●
●
●
●
●
13.4
12.8
3.4
3.1
1.2
±V
±V
±V
±V
±V
IOUT
Output Current
VOUT = ±12.8V
VOUT = ±3.1V
±15V
±5V
●
●
25
20
mA
mA
VCM = ±12V
VCM = ±2.5V
VCM = ±0.5V
84
77
66
dB
dB
dB
ISC
Short-Circuit Current
VOUT = 0V, VIN = ±3V
±15V
●
32
mA
SR
Slew Rate
AV = –2, (Note 5)
±15V
±5V
●
●
475
185
V/µs
V/µs
IS
Supply Current
±15V
±5V
●
●
4
5.8
5.6
mA
mA
LT1360
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the temperature range
– 40°C ≤ TA ≤ 85°C, VCM = 0V unless otherwise noted. (Note 9)
SYMBOL
VOS
PARAMETER
Input Offset Voltage
CONDITIONS
(Note 4)
VSUPPLY
±15V
±5V
±2.5V
●
●
●
MIN
Input VOS Drift
(Note 7)
TYP
MAX
2.0
2.0
2.2
UNITS
mV
mV
mV
±2.5V to ±15V
●
12
µV/°C
IOS
Input Offset Current
±2.5V to ±15V
●
400
nA
IB
Input Bias Current
±2.5V to ±15V
●
1.8
µA
CMRR
Common Mode Rejection Ratio
±15V
±5V
±2.5V
●
●
●
PSRR
Power Supply Rejection Ratio
VS = ±2.5V to ±15V
●
90
dB
AVOL
Large-Signal Voltage Gain
VOUT = ±12V, RL = 1k
VOUT = ±10V, RL = 500Ω
VOUT = ±2.5V, RL = 500Ω
VOUT = ±2.5V, RL = 150Ω
VOUT = ±1V, RL = 500Ω
±15V
±15V
±5V
±5V
±2.5V
●
●
●
●
●
2.5
1.5
1.5
0.6
1.3
V/mV
V/mV
V/mV
V/mV
V/mV
VOUT
Output Swing
RL = 1kΩ, VIN = ±40mV
RL = 500Ω, VIN = ±40mV
RL = 500Ω, VIN = ±40mV
RL = 150Ω, VIN = ±40mV
RL = 500Ω, VIN = ±40mV
±15V
±15V
±5V
±5V
±2.5V
●
●
●
●
●
13.4
12.0
3.4
3.0
1.2
±V
±V
±V
±V
±V
IOUT
Output Current
VOUT = ±12.0V
VOUT = ±3.0V
±15V
±5V
●
●
24
20
mA
mA
ISC
Short-Circuit Current
VOUT = 0V, VIN = ±3V
±15V
●
30
mA
SR
Slew Rate
AV = –2, (Note 5)
±15V
±5V
●
●
450
175
V/µs
V/µs
IS
Supply Current
±15V
±5V
●
●
VCM = ±12V
VCM = ±2.5V
VCM = ±0.5V
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 ±2V on the output with ±1.75V input for ±5V supplies.
9
84
77
66
dB
dB
dB
6.0
5.8
mA
mA
Note 6: Full power bandwidth is calculated from the slew rate
measurement: FPBW = SR/2πVP.
Note 7: This parameter is not 100% tested.
Note 8: The LT1360C is guaranteed functional over the operating
temperature range of –40°C to 85°C.
Note 9: The LT1360C is guaranteed to meet specified performance from
0°C to 70°C. The LT1360C is designed, characterized and expected to
meet specified performance from – 40°C to 85°C, but is not tested or QA
sampled at these temperatures. For guaranteed I-grade parts, consult the
factory.
5
LT1360
U W
TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current vs Supply Voltage
and Temperature
0.6
V+
6
TA = 25°C
∆VOS < 1mV
– 0.5
125°C
4
25°C
3
–55°C
2
–1.5
–2.0
2.0
1.5
1.0
V–
5
10
15
SUPPLY VOLTAGE (±V)
0
20
5
10
15
SUPPLY VOLTAGE (±V)
0.5
0.4
0.3
0.2
0.1
VS = ±15V
TA = 25°C
AV = 101
RS = 100k
in
10
en
1
1
–25
0
25
50
75
TEMPERATURE (°C)
100
10
125
100
10
76
75
74
Output Voltage Swing vs
Load Current
– 0.5
–2
RL = 500Ω
–3
3
RL = 500Ω
2
RL = 1k
V–
–25
0
25
50
75
TEMPERATURE (°C)
100
125
1360 G07
10k
1360 G06
RL = 1k
1
73
100
1k
LOAD RESISTANCE (Ω)
V+
–1
OUTPUT VOLTAGE SWING (V)
OPEN-LOOP GAIN (dB)
60
TA = 25°C
77
6
65
V+
78
72
–50
70
Output Voltage Swing vs
Supply Voltage
81
79
VS = ±5V
75
1360 G05
Open-Loop Gain vs Temperature
RL = 1k
VO = ±12V
VS = ±15V
VS = ±15V
80
0.1
100k
1k
10k
FREQUENCY (Hz)
1360 G04
80
TA = 25°C
OUTPUT VOLTAGE SWING (V)
0
–50
INPUT VOLTAGE NOISE (nV/√Hz)
INPUT BIAS CURRENT (µA)

85
10
100
INPUT CURRENT NOISE (pA/√Hz)

15
Open-Loop Gain vs
Resistive Load
Input Noise Spectral Density
VS = ±15V
IB+ + IB–
IB = ————
2
–10
–5
0
5
10
INPUT COMMON MODE VOLTAGE (V)
1360 G03
Input Bias Current vs
Temperature
0.6
0.2
1360 G02
1360 G01
0.7

0.3
0
–15
20
OPEN-LOOP GAIN (dB)
0

0.4
0.1
0.5
1
VS = ±15V
TA = 25°C
IB+ + IB–
IB = ————
2
0.5
–1.0
INPUT BIAS CURRENT (µA)
COMMON MODE RANGE (V)
5
SUPPLY CURRENT (mA)
Input Bias Current vs
Input Common Mode Voltage
Input Common Mode Range vs
Supply Voltage
0
5
10
15
SUPPLY VOLTAGE (±V)
20
1360 G08
VS = ±5V
VIN = 100mV
85°C
–1.0
25°C
–1.5
– 40°C
–2.0
– 40°C
2.0
1.5
25°C
1.0
85°C
0.5
V–
– 50 – 40 –30 –20 –10 0 10 20 30 40 50
OUTPUT CURRENT (mA)
1360 G09
LT1360
U W
TYPICAL PERFORMANCE CHARACTERISTICS
Output Short-Circuit Current vs
Temperature
Gain and Phase vs Frequency
70
100
VS = ±5V
65
120
PHASE
60
55
SOURCE
50
SINK
45
10
50
AV = 1
1
VS = ±15V
TA = 25°C
35
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
0.01
10k
125
40
60
VS = ±5V
30
100k
1M
10M
FREQUENCY (Hz)
20
20
0
TA = 25°C
AV = –1
RF = RG = 1k
0
–10
10k
100M
40
VS = ±5V
10
0.1
40
80
VS = ±15V
GAIN
GAIN (dB)
OUTPUT IMPEDANCE (Ω)
60
100
VS = ±15V
AV = 10
AV = 100
PHASE (DEG)
OUTPUT SHORT-CIRCUIT CURRENT (mA)
70
Output Impedance vs
Frequency
100k
100M
1M
10M
FREQUENCY (Hz)
1360 G10
1360 G14
1360 G11
Settling Time vs Output Step
(Noninverting)
Settling Time vs Output Step
(Inverting)
6
8
10mV
6
1mV
4
OUTPUT STEP (V)
4
2
0
–2
–4
70
2
0
–2
–4
10mV
1mV
–8
20
40
60
80
SETTLING TIME (ns)
0
100
20
40
60
80
SETTLING TIME (ns)
Gain Bandwidth and Phase
Margin vs Temperature
5
45
4
40
3
30
60
GAIN BANDWIDTH
VS = ±15V
0
25
50
75
TEMPERATURE (°C)
25
20
15
GAIN BANDWIDTH
VS = ±5V
–25
38
36
100
32
100
30
0
5
10
15
SUPPLY VOLTAGE (±V)
20
1360 G15
Frequency Response vs
Supply Voltage (AV = –1)
5
TA = 25°C
AV = 1
RL = 1k
4
3
±15V
2
1
0
–1
–2
±5V
2
±5V
–2
–3
5
–4
–4
±2.5V
1M
10M
FREQUENCY (Hz)
±15V
0
–1
–3
–5
100k
TA = 25°C
AV = –1
RF = RG = 1k
1
10
0
125
1360 G16
34
GAIN BANDWIDTH
GAIN (dB)
35
GAIN (dB)
PHASE MARGIN
VS = ±15V
50
PHASE MARGIN (DEG)
GAIN BANDWIDTH (MHz)
PHASE MARGIN
VS = ±5V
30
–50
40
50
Frequency Response vs
Supply Voltage (AV = 1)
70
40
42
1360 G13
1360 G12
50
60
30
–10
0
44
1mV
–8
–10
46
PHASE MARGIN
40
–6
–6
48
TA = 25°C
10mV
1mV
10mV
50
PHASE MARGIN (DEG)
VS = ±15V
AV = –1
RF = 1k
CF = 3pF
GAIN BANDWIDTH (MHz)
VS = ±15V
AV = 1
RL = 1k
8
OUTPUT STEP (V)
80
10
10
80
Gain Bandwidth and Phase
Margin vs Supply Voltage
100M
1360 G17
–5
100k
±2.5V
1M
10M
FREQUENCY (Hz)
100M
1360 G18
7
LT1360
U W
TYPICAL PERFORMANCE CHARACTERISTICS
Frequency Response vs
Capacitive Load
12
C = 500pF
6
C = 100pF
4
C = 50pF
2
0
C=0
–2
–4
–6
–8
1M
10M
FREQUENCY (Hz)
– PSRR
80
60
40
20
0
100
100M
VS = ±15V
TA = 25°C
+PSRR
10k 100k
1M
FREQUENCY (Hz)
10M
SLEW RATE (V/µs)
600
400
1600
700
VS = ±15V
600
500
VS = ± 5V
400
0
0
25
50
75
TEMPERATURE (°C)
100
1000
800
600
0
125
2
4
6 8 10 12 14 16 18
INPUT LEVEL (VP-P)
Undistorted Output Swing vs
Frequency (±5V)
Undistorted Output Swing vs
Frequency (±15V)
10
AV = –1
OUTPUT VOLTAGE (VP-P)
25
AV = 1
20
0.0001
1k
10k
FREQUENCY (Hz)
100k
1360 G25
AV = 1
15
10
5
20
1360 G24
30
100
1200
1360 G23
0.01
10
1400
0
–25
1360 G22
Total Harmonic Distortion
vs Frequency
100M
200
200
– 50
15
AV = –1
10M
400
300
200
TA = 25°C
VO = 3VRMS
RL = 500Ω
100k
1M
FREQUENCY (Hz)
TA = 25°C
VS = ±15V
AV = –1
RF = RG = 1k
SR + + SR –
SR = —————
2
1800
OUTPUT VOLTAGE (VP-P)
SLEW RATE (V/µs)
800
10k
Slew Rate vs Input Level
AV = –2
SR + + SR –
SR = —————
2
800
1000
0.001
20
2000
900
1200
5
10
SUPPLY VOLTAGE (±V)
40
1360 G21
SLEW RATE (V/µs)
TA = 25°C
AV = –1
RF = RG = 1k
SR+ + SR –
SR = —————
2
0
60
1k
100M
1000
1400
80
Slew Rate vs Temperature
Slew Rate vs Supply Voltage
1600
100
1360 G20
2000
1800
VS = ±15V
TA = 25°C
0
1k
1360 G19
TOTAL HARMONIC DISTORTION (%)
COMMON-MODE REJECTION RATIO (dB)
8
POWER SUPPLY REJECTION RATIO (dB)
VOLTAGE MAGNITUDE (dB)
120
100
C = 1000pF
VS = ±15V
TA = 25°C
AV = –1
10
8
Common Mode Rejection Ratio
vs Frequency
Power Supply Rejection Ratio
vs Frequency
VS = ±15V
RL = 1k
AV = 1, 1% MAX DISTORTION
AV = –1, 2% MAX DISTORTION
0
100k
1M
FREQUENCY (Hz)
1360 G26
AV = 1
6
4
2
10M
AV = –1
8
VS = ±5V
RL = 1k
2% MAX DISTORTION
0
100k
1M
FREQUENCY (Hz)
10M
1360 G27
LT1360
U W
TYPICAL PERFORMANCE CHARACTERISTICS
–40
0.50
VS = ±15V
VO = 2VP-P
RL = 500Ω
AV = 2
0.25
3RD HARMONIC
DIFFERENTIAL GAIN
–50
DIFFERENTIAL PHASE (DEG)
HARMONIC DISTORTION (dB)
–30
–60
–70
2ND HARMONIC
–80
–90
100k 200k
400k
1M 2M
FREQUENCY (Hz)
4M
10M
0
0.40
0.36
DIFFERENTIAL PHASE
0.32
0.28
±5
±10
SUPPLY VOLTAGE (V)
50
±15
0
10p
100p
1000p 0.01µ
0.1µ
CAPACITIVE LOAD (F)
1µ
1360 G30
1360 G29
1360 TA31
Small-Signal Transient
(AV = –1, CL = 500pF)
1360 TA32
1360 TA33
Large-Signal Transient
(AV = 1, CL = 10,000pF)
Large-Signal Transient
(AV = –1)
1360 TA34
AV = –1
AV = 1
Small-Signal Transient
(AV = –1)
Large-Signal Transient
(AV = 1)
VS = ±15V
TA = 25°C
AV = 2
RL = 150Ω
TA = 25°C
1360 G28
Small-Signal Transient
(AV = 1)
Capacitive Load Handling
100
OVERSHOOT (%)
Differential Gain and Phase
vs Supply Voltage
DIFFERENTIAL GAIN (%)
2nd and 3rd Harmonic Distortion
vs Frequency
1360 TA35
1360 TA36
9
LT1360
U
U
W
U
APPLICATIONS INFORMATION
The LT1360 may be inserted directly into AD817, AD847,
EL2020, EL2044, and LM6361 applications improving
both DC and AC performance, provided that the nulling
circuitry is removed. The suggested nulling circuit for the
LT1360 is shown below.
Offset Nulling
V+
3
7
+
6
LT1360
2
4
–
8
1
10k
V–
1360 AI01
Capacitive Loading
The LT1360 is 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 smallsignal response with 500pF load shows 60% peaking. The
large-signal response with a 10,000pF load shows the
output slew rate being limited to 5V/µs 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., 75Ω) should be placed in
series with the output. The other end of the cable should
be terminated with the same value resistor to ground.
Layout and Passive Components
The parallel combination of the feedback resistor and gain
setting resistor on the inverting input can combine with
the input capacitance to form a pole which can cause
peaking or oscillations. For feedback resistors greater
than 5kW, 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.
10
2
AV = 2
RF = RG = 500Ω
RL = 150Ω
0
GAIN (dB)
The LT1360 amplifier is easy to apply and tolerant of less
than ideal layouts. For maximum performance (for example fast settling time) use a ground plane, short lead
lengths, and RF-quality bypass capacitors (0.01µF to
0.1µF). For high drive current applications use low ESR
bypass capacitors (1µF to 10µF tantalum). Sockets
should be avoided when maximum frequency performance is required, although low profile sockets can
provide reasonable performance up to 50MHz. For
more details see Design Note 50.
Cable Driver Frequency Response
VS = ±15V
VS = ±10V
VS = ±2.5V
VS = ±5V
–2
IN
–4
+
LT1360
–
510Ω
–6
75Ω
OUT
75Ω
510Ω
–8
1
10
FREQUENCY (MHz)
100
1360 AI02
LT1360
U
W
U
U
APPLICATIONS INFORMATION
Input Considerations
Power Dissipation
Each of the LT1360 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 LT1360 combines high speed and large output drive
in a small package. 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:
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 application 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.
LT1360CN8: TJ = TA + (PD x 130°C/W)
LT1360CS8: TJ = TA + (PD x 190°C/W)
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). Therefore PDMAX is:
PDMAX = (V+ – V–)(ISMAX) + (V+/2)2/RL
Example: LT1360CS8 at 70°C, VS = ±15V, RL = 250W
PDMAX = (30V)(5.8mA) + (7.5V)2/250W = 399mW
TJMAX = 70°C + (399mW)(190°C/W) = 146°C
11
LT1360
U
W
U
U
APPLICATIONS INFORMATION
Circuit Operation
The LT1360 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 500Ω 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 LT1360 is 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
12
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.
Comparison to Current Feedback Amplifiers
The LT1360 enjoys the high slew rates of Current Feedback Amplifiers (CFAs) while maintaining the characteristics of a true voltage feedback amplifier. The primary
differences are that the LT1360 has two high impedance
inputs and its closed loop bandwidth decreases as the gain
increases. CFAs have a low impedance inverting input and
maintain relatively constant bandwidth with increasing
gain. The LT1360 can be used in all traditional op amp
configurations including integrators and applications such
as photodiode amplifiers and I-to-V converters where
there may be significant capacitance on the inverting
input. The frequency compensation is internal and not
dependent on the value of the feedback resistor. For CFAs,
the feedback resistance is fixed for a given bandwidth and
capacitance on the inverting input can cause peaking or
oscillations. The slew rate of the LT1360 in noninverting
gain configurations is also superior in most cases.
LT1360
W
W
SI PLIFIED SCHE ATIC
V+
R1
500Ω
+IN
RC
OUT
–IN
C
V–
CC
1360 SS01
13
LT1360
U
PACKAGE DESCRIPTION
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
1
2
3
4
0.255 ± 0.015*
(6.477 ± 0.381)
0.300 – 0.325
(7.620 – 8.255)
0.009 – 0.015
(0.229 – 0.381)
(
+0.035
0.325 –0.015
8.255
+0.889
–0.381
)
0.045 – 0.065
(1.143 – 1.651)
0.065
(1.651)
TYP
0.100
(2.54)
BSC
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)
14
0.130 ± 0.005
(3.302 ± 0.127)
0.125
(3.175) 0.020
MIN
(0.508)
MIN
0.018 ± 0.003
(0.457 ± 0.076)
N8 1098
LT1360
U
PACKAGE DESCRIPTION
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)
8
7
6
5
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
1
0.010 – 0.020
× 45°
(0.254 – 0.508)
0.008 – 0.010
(0.203 – 0.254)
0.053 – 0.069
(1.346 – 1.752)
0°– 8° TYP
0.016 – 0.050
(0.406 – 1.270)
0.014 – 0.019
(0.355 – 0.483)
TYP
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
2
3
4
0.004 – 0.010
(0.101 – 0.254)
0.050
(1.270)
BSC
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.
SO8 1298
15
LT1360
U
TYPICAL APPLICATIONS
Photodiode Preamp with AC Coupling Loop
1pF
1N5712
1N5712
10k
VS = ±5V
f–3dB = 100KHz, 5.5MHz
iPD
–
VOUT
LT1360
SFH205
+
10k
2k
2k
300pF
1µF
10k
–5V
–
5.1k
–
1/2 LT1358
+
1/2 LT1358
+
1360 TA03
1MHz, 4th Order Butterworth Filter
909Ω
1.1k
47pF
22pF
909Ω
2.67k
VIN
–
1.1k
2.21k
LT1360
220pF
+
–
LT1360
470pF
VOUT
+
1360 TA04
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT1361/LT1362
Dual and Quad 50MHz, 800V/µs Op Amps
Dual and Quad Versions of LT1360
LT1363
70MHz, 1000V/µs Op Amp
Faster Version of LT1360, VOS = 1.5mV, IS = 6.3mA
LT1357
25MHz, 600V/µs Op Amp
Lower Power Version of LT1360, VOS = 0.6mV, IS = 2mA
LT1812
100MHz, 750V/µs Op Amp
Low Voltage, Low Power LT1360, VOS = 1mV, IS = 3mA
16
Linear Technology Corporation
1360fa LT/TP 0400 2K REV A • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com
 LINEAR TECHNOLOGY CORPORATION 1994