Page 1
FEATURES
■
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
U
APPLICATIO S
■
Wideband Amplifiers
■
Buffers
■
Active Filters
■
Video and RF Amplification
■
Cable Drivers
■
Data Acquisition Systems
LT1360
50MHz, 800V/µs Op Amp
U
DESCRIPTIO
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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
C-Load is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
Two Op Amp Instrumentation Amplifier
R5
220Ω
R1
10k
–
V
IN
+
R
4
GAIN
=
R
3
TRIM R5 FOR GAIN
TRIM R1 FOR COMMON-MODE REJECTION
BW = 500kHz
–
+
+
1
R2
1k
LT1360
RRR
12213
+
R3
1k
RR
+
23
()
+
R
R
4
5
U
AV = –1 Large-Signal Response
R4
10k
–
LT1360
V
OUT
+
=
102
1360 TA01
1360 TA02
1
Page 2
LT1360
8
7
6
54
3
2
1NULL
–IN
+IN
V
–
NC
V
OUT
V
+
NULL
TOP VIEW
N8 PACKAGE, 8-LEAD PDIP
WW
W
ABSOLUTE MAXIMUM RATINGS
U
(Note 1)
Total Supply Voltage (V+ to V–) ............................... 36V
Differential Input Voltage
(Transient Only) (Note 2)................................... ±10V
Input Voltage ............................................................±V
Output Short Circuit Duration (Note 3) ............ Indefinite
U
W
U
PACKAGE/ORDER INFORMATION
ORDER PART
NUMBER
LT1360CN8
= 150°C, θJA = 130°C/ W
JMAX
Consult factory for Industrial and Military grade parts.
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)
S
Plastic Package ................................................150°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
TOP VIEW
1NULL
2
–IN
+IN
3
–
V
S8 PACKAGE, 8-LEAD PLASTIC SO
T
= 150°C, θJA = 190°C/WT
JMAX
8
7
6
54
NULL
+
V
V
OUT
NC
ORDER PART
NUMBER
LT1360CS8
S8 PART MARKING
1360
T
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS V
V
OS
I
OS
I
B
e
n
i
n
R
IN
C
IN
CMRR Common Mode Rejection Ratio V
PSRR Power Supply Rejection Ratio VS = ±2.5V to ±15V 93 105 dB
Input Offset Voltage (Note 4) ±15V 0.3 1.0 mV
Input Offset Current ±2.5V to ±15V 80 250 nA
Input Bias Current ±2.5V to ±15V 0.3 1.0 µA
Input Noise Voltage f = 10kHz ±2.5V to ±15V 9 nV/√Hz
Input Noise Current f = 10kHz ±2.5V to ±15V 0.9 pA/√Hz
Input Resistance V
Input Resistance Differential ±15V 5 MΩ
Input Capacitance ±15V 3 pF
Input Voltage Range
Input Voltage Range
+
–
= ±12V ±15V 20 50 MΩ
CM
= ±12V ±15V 86 92 dB
CM
V
= ±2.5V ±5V 79 84 dB
CM
V
= ±0.5V ±2.5V 68 74 dB
CM
= 25°C, V
A
= 0V unless otherwise noted.
CM
SUPPLY
±5V 0.3 1.0 mV
±2.5V 0.4 1.2 mV
±15V 12.0 13.4 V
±5V 2.5 3.4 V
±2.5V 0.5 1.1 V
±15V –13.2 –12.0 V
±5V –3.2 –2.5 V
±2.5V –0.9 –0.5 V
MIN TYP MAX UNITS
2
Page 3
ELECTRICAL CHARACTERISTICS
T
= 25°C, V
A
= 0V unless otherwise noted.
CM
LT1360
SYMBOL PARAMETER CONDITIONS V
A
V
I
I
VOL
OUT
OUT
SC
Large-Signal Voltage Gain V
= ±12V, RL = 1k ±15V 4.5 9.0 V/mV
OUT
V
= ±10V, RL = 500Ω±15V 3.0 6.5 V/mV
OUT
V
= ±2.5V, RL = 500Ω±5V 3.0 6.4 V/mV
OUT
V
= ±2.5V, RL = 150Ω±5V 1.5 4.2 V/mV
OUT
V
= ±1V, RL = 500Ω±2.5V 2.5 5.2 V/mV
OUT
Output Swing RL = 1k, V
RL = 500Ω, V
R
= 500Ω, V
L
RL = 150Ω, V
R
= 500Ω, V
L
Output Current V
Short-Circuit Current V
= ±13V ±15V 26 34 mA
OUT
V
= ±3.2V ±5V 21 29 mA
OUT
= 0V, V
OUT
= ±40mV ±15V 13.5 13.9 ±V
IN
= ±40mV ±15V 13.0 13.6 ±V
IN
= ±40mV ±5V 3.5 4.0 ±V
IN
= ±40mV ±5V 3.2 3.8 ±V
IN
= ±40mV ±2.5V 1.3 1.7 ±V
IN
= ±3V ±15V 40 54 mA
IN
SUPPLY
MIN TYP MAX UNITS
SR Slew Rate AV = –2, (Note 5) ±15V 600 800 V/µs
±5V 250 350 V/µs
Full Power Bandwidth 10V Peak, (Note 6) ±15V 12.7 MHz
3V Peak, (Note 6) ±5V 18.6 MHz
GBW Gain Bandwidth f = 1MHz ±15V 50 MHz
±5V 37 MHz
±2.5V 32 MHz
tr, t
f
Rise Time, Fall Time AV = 1, 10%-90%, 0.1V ±15V 3.1 ns
±5V 4.3 ns
Overshoot AV = 1, 0.1V ±15V 35 %
±5V 27 %
Propagation Delay 50% VIN to 50% V
, 0.1V ±15V 5.2 ns
OUT
±5V 6.4 ns
t
s
Settling Time 10V Step, 0.1%, AV = –1 ±15V 60 ns
10V Step, 0.01%, AV = –1 ±15V 90 ns
5V Step, 0.1%, A
= –1 ±5V 65 ns
V
Differential Gain f = 3.58MHz, AV = 2, RL = 150Ω±15V 0.20 %
±5V 0.20 %
f = 3.58MHz, A
= 2, RL = 1k ±15V 0.04 %
V
±5V 0.02 %
Differential Phase f = 3.58MHz, AV = 2, RL = 150Ω±15V 0.40 Deg
±5V 0.30 Deg
f = 3.58MHz, A
= 2, RL = 1k ±15V 0.07 Deg
V
±5V 0.26 Deg
R
O
I
S
Output Resistance AV = 1, f = 1MHz ±15V 1.4 Ω
Supply Current ±15V 4.0 5.0 mA
±5V 3.8 4.8 mA
3
Page 4
LT1360
ELECTRICAL CHARACTERISTICS
0°C ≤ TA ≤ 70°C, V
SYMBOL PARAMETER CONDITIONS V
V
OS
Input Offset Voltage (Note 4) ±15V ● 1.5 mV
= 0V unless otherwise noted.
CM
The ● denotes the specifications which apply over the temperature range
SUPPLY
±5V
±2.5V
MIN TYP MAX UNITS
● 1.5 mV
● 1.7 mV
Input VOS Drift (Note 7) ±2.5V to ±15V ● 912 µV/°C
I
OS
I
B
CMRR Common Mode Rejection Ratio V
Input Offset Current ±2.5V to ±15V ● 350 nA
Input Bias Current ±2.5V to ±15V ● 1.5 µA
= ±12V ±15V ● 84 dB
CM
= ±2.5V ±5V ● 77 dB
V
CM
V
= ±0.5V ±2.5V ● 66 dB
CM
PSRR Power Supply Rejection Ratio VS = ±2.5V to ±15V ● 91 dB
A
V
I
I
VOL
OUT
OUT
SC
Large-Signal Voltage Gain V
= ±12V, RL = 1k ±15V ● 3.6 V/mV
OUT
= ±10V, RL = 500Ω±15V ● 2.4 V/mV
V
OUT
= ±2.5V, RL = 500Ω±5V ● 2.4 V/mV
V
OUT
V
= ±2.5V, RL = 150Ω±5V ● 1.0 V/mV
OUT
V
= ±1V, RL = 500Ω±2.5V ● 2.0 V/mV
OUT
Output Swing RL = 1k, V
= 500Ω, V
R
L
R
= 500Ω, V
L
= 150Ω, V
R
L
= 500Ω, V
R
L
Output Current V
Short-Circuit Current V
= ±12.8V ±15V ● 25 mA
OUT
V
= ±3.1V ±5V ● 20 mA
OUT
= 0V, V
OUT
= ±40mV ±15V ● 13.4 ±V
IN
= ±40mV ±15V ● 12.8 ±V
IN
= ±40mV ±5V ● 3.4 ±V
IN
= ±40mV ±5V ● 3.1 ±V
IN
= ±40mV ±2.5V ● 1.2 ±V
IN
= ±3V ±15V ● 32 mA
IN
SR Slew Rate AV = –2, (Note 5) ±15V ● 475 V/µs
±5V
I
S
Supply Current ±15V ● 5.8 mA
● 185 V/µs
±5V ● 5.6 mA
4
Page 5
LT1360
ELECTRICAL CHARACTERISTICS
–40°C ≤ TA ≤ 85°C, V
SYMBOL PARAMETER CONDITIONS V
V
OS
Input Offset Voltage (Note 4) ±15V ● 2.0 mV
= 0V unless otherwise noted. (Note 9)
CM
The ● denotes the specifications which apply over the temperature range
SUPPLY
±5V
±2.5V
MIN TYP MAX UNITS
● 2.0 mV
● 2.2 mV
Input VOS Drift (Note 7) ±2.5V to ±15V ● 912 µV/°C
I
OS
I
B
CMRR Common Mode Rejection Ratio V
Input Offset Current ±2.5V to ±15V ● 400 nA
Input Bias Current ±2.5V to ±15V ● 1.8 µA
= ±12V ±15V ● 84 dB
CM
= ±2.5V ±5V ● 77 dB
V
CM
= ±0.5V ±2.5V ● 66 dB
V
CM
PSRR Power Supply Rejection Ratio VS = ±2.5V to ±15V ● 90 dB
A
V
I
I
VOL
OUT
OUT
SC
Large-Signal Voltage Gain V
= ±12V, RL = 1k ±15V ● 2.5 V/mV
OUT
= ±10V, RL = 500Ω±15V ● 1.5 V/mV
V
OUT
= ±2.5V, RL = 500Ω±5V ● 1.5 V/mV
V
OUT
V
= ±2.5V, RL = 150Ω±5V ● 0.6 V/mV
OUT
= ±1V, RL = 500Ω±2.5V ● 1.3 V/mV
V
OUT
Output Swing RL = 1kΩ, V
= 500Ω, V
R
L
R
= 500Ω, V
L
= 150Ω, V
R
L
= 500Ω, V
R
L
Output Current V
Short-Circuit Current V
= ±12.0V ±15V ● 24 mA
OUT
V
= ±3.0V ±5V ● 20 mA
OUT
= 0V, V
OUT
= ±40mV ±15V ● 13.4 ±V
IN
= ±40mV ±15V ● 12.0 ±V
IN
= ±40mV ±5V ● 3.4 ±V
IN
= ±40mV ±5V ● 3.0 ±V
IN
= ±40mV ±2.5V ● 1.2 ±V
IN
= ±3V ±15V ● 30 mA
IN
SR Slew Rate AV = –2, (Note 5) ±15V ● 450 V/µs
±5V
I
S
Supply Current ±15V ● 6.0 mA
● 175 V/µs
±5V ● 5.8 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 ±2V on the output with ±1.75V input for ±5V supplies.
Note 6: Full power bandwidth is calculated from the slew rate
measurement: FPBW = SR/2πV
.
P
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
Page 6
LT1360
OUTPUT CURRENT (mA)
V
–
OUTPUT VOLTAGE SWING (V)
1.0
1.5
0.5
V
+
–0.5
–1.0
–1.5
2.0
–2.0
–50 –40 –10 30 40 5001020–20–30
1360 G09
VS = ±5V
V
IN
= 100mV
85°C
85°C
25°C
25°C
–40°C
–40°C
W
U
TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current vs Supply Voltage
and Temperature
6
5
4
3
SUPPLY CURRENT (mA)
2
1
10501520
SUPPLY VOLTAGE (±V)
Input Bias Current vs
Temperature
0.7
0.6
0.5
0.4
0.3
0.2
INPUT BIAS CURRENT (µA)
0.1
VS = ±15V
=
I
B
125°C
25°C
–55°C
+
I
+ I
B
————
2
1360 G01
–
B
Input Common Mode Range vs
Supply Voltage
+
V
TA = 25°C
–0.5
–1.0
–1.5
–2.0
2.0
1.5
COMMON MODE RANGE (V)
1.0
0.5
–
V
< 1mV
∆V
OS
SUPPLY VOLTAGE (±V)
Input Noise Spectral Density
100
e
n
i
n
10
INPUT VOLTAGE NOISE (nV/√Hz)
Input Bias Current vs
Input Common Mode Voltage
0.6
VS = ±15V
= 25°C
T
A
0.5
0.4
0.3
0.2
+
I
B
I
=
————
B
+ I
2
INPUT BIAS CURRENT (µA)
0.1
10501520
1360 G02
0
–15 –10 0 10 155–5
INPUT COMMON MODE VOLTAGE (V)
Open-Loop Gain vs
Resistive Load
85
= 25°C
T
A
80
75
70
OPEN-LOOP GAIN (dB)
65
VS = ±15V
= 25°C
T
A
= 101
A
V
= 100k
R
S
10
INPUT CURRENT NOISE (pA/√Hz)
1
–
B
1360 G03
VS = ±15V
VS = ±5V
0
–50 –25 25 100 12550 750
Open-Loop Gain vs Temperature
81
RL = 1k
80
= ±12V
V
O
= ±15V
V
S
79
78
77
76
75
OPEN-LOOP GAIN (dB)
74
73
72
–50 –25 25 100 12550 750
6
TEMPERATURE (°C)
TEMPERATURE (°C)
1360 G04
1360 G07
1
10
1k100 100k10k
FREQUENCY (Hz)
Output Voltage Swing vs
Supply Voltage
+
V
TA = 25°C
–1
–2
–3
3
2
OUTPUT VOLTAGE SWING (V)
1
–
V
SUPPLY VOLTAGE (±V)
0.1
1360 G05
60
10
100 10k
LOAD RESISTANCE (Ω)
Output Voltage Swing vs
Load Current
RL = 1k
R
= 500Ω
L
R
= 500Ω
L
R
= 1k
L
10501520
1360 G08
1k
1360 G06
Page 7
W
U
TYPICAL PERFORMANCE CHARACTERISTICS
LT1360
Output Short-Circuit Current vs
Temperature
70
65
60
55
50
45
40
OUTPUT SHORT-CIRCUIT CURRENT (mA)
35
–50 –25 25 100 12550 750
TEMPERATURE (°C)
SOURCE
SINK
Settling Time vs Output Step
(Noninverting)
10
VS = ±15V
8
= 1
A
V
R
= 1k
L
6
4
2
0
–2
OUTPUT STEP (V)
–4
–6
–8
–10
0 40 80 1006020
10mV
10mV
SETTLING TIME (ns)
VS = ±5V
1mV
1mV
1360 G10
1360 G12
Output Impedance vs
Frequency
100
AV = 100
10
1
0.1
OUTPUT IMPEDANCE (Ω)
0.01
10k
100k 100M
1M
FREQUENCY (Hz)
Settling Time vs Output Step
(Inverting)
10
VS = ±15V
8
= –1
A
V
= 1k
R
F
6
= 3pF
C
F
4
2
0
–2
OUTPUT STEP (V)
–4
–6
–8
–10
0 40 80 1006020
10mV
SETTLING TIME (ns)
AV = 10
AV = 1
10mV
VS = ±15V
= 25°C
T
A
10M
1mV
1mV
1360 G11
1360 G13
Gain and Phase vs Frequency
70
60
50
40
30
GAIN (dB)
20
10
0
–10
10k
GAIN
= 25°C
T
A
= –1
A
V
R
= RG = 1k
F
PHASE
VS = ±15V
VS = ±5V
100k 100M
1M
FREQUENCY (Hz)
Gain Bandwidth and Phase
Margin vs Supply Voltage
80
70
60
50
GAIN BANDWIDTH (MHz)
40
30
PHASE MARGIN
GAIN BANDWIDTH
10501520
SUPPLY VOLTAGE (±V)
VS = ±15V
VS = ±5V
10M
TA = 25°C
1360 G14
1360 G15
120
100
PHASE (DEG)
80
60
40
20
0
50
48
46
PHASE MARGIN (DEG)
44
42
40
38
36
34
32
30
Gain Bandwidth and Phase
Margin vs Temperature
80
PHASE MARGIN
= ±5V
V
S
70
60
50
GAIN BANDWIDTH
GAIN BANDWIDTH (MHz)
= ±5V
V
40
S
30
–50 –25 25 100 12550 750
TEMPERATURE (°C)
PHASE MARGIN
= ±15V
V
S
GAIN BANDWIDTH
= ±15V
V
S
1360 G16
50
45
40
PHASE MARGIN (DEG)
35
30
25
20
15
10
5
0
GAIN (dB)
Frequency Response vs
Supply Voltage (AV = 1)
5
T
= 25°C
A
4
= 1
A
V
R
= 1k
3
L
2
1
0
–1
–2
–3
–4
–5
100k
1M 100M
FREQUENCY (Hz)
±5V
10M
±2.5V
±15V
1360 G17
Frequency Response vs
Supply Voltage (AV = –1)
5
T
= 25°C
A
4
= –1
A
V
R
= RG = 1k
3
F
2
1
0
GAIN (dB)
–1
–2
–3
–4
–5
100k
1M 100M
FREQUENCY (Hz)
±15V
±5V
±2.5V
10M
1360 G18
7
Page 8
LT1360
FREQUENCY (Hz)
0
COMMON-MODE REJECTION RATIO (dB)
40
20
120
100
80
60
1k 100M10M1M100k10k
1360 G21
VS = ±15V
T
A
= 25°C
W
U
TYPICAL PERFORMANCE CHARACTERISTICS
Frequency Response vs
Capacitive Load
12
VS = ±15V
10
= 25°C
T
A
= –1
A
8
V
6
4
2
0
–2
VOLTAGE MAGNITUDE (dB)
–4
–6
–8
1M
C = 1000pF
10M
FREQUENCY (Hz)
Slew Rate vs Supply Voltage
2000
TA = 25°C
1800
1600
1400
1200
1000
SLEW RATE (V/µs)
A
V
R
F
SR =
800
600
400
200
0
015105
= –1
= RG = 1k
+
+ SR
SR
—————
2
SUPPLY VOLTAGE (±V)
–
C = 500pF
C = 100pF
C = 50pF
C = 0
1360 G19
1360 G22
100M
Power Supply Rejection Ratio
vs Frequency
100
80
60
40
20
POWER SUPPLY REJECTION RATIO (dB)
0
+PSRR
–PSRR
100k 1M1k 10k100 10M 100M
FREQUENCY (Hz)
Slew Rate vs Temperature
1000
A
= –2
900
800
700
600
500
SLEW RATE (V/µs)
400
300
200
–50 –25 25 100 12550 750
TEMPERATURE (°C)
V
SR = —————
V
= ±15V
S
= ±5V
V
S
VS = ±15V
= 25°C
T
A
SR+ + SR
2
1360 G20
–
1360 G23
Common Mode Rejection Ratio
vs Frequency
Slew Rate vs Input Level
2000
TA = 25°C
SLEW RATE (V/µs)
1800
1600
1400
1200
1000
800
600
400
200
= ±15V
V
S
= –1
A
V
= RG = 1k
R
F
SR =
0
0 8 16 2012421018146
+
+ SR
SR
—————
2
INPUT LEVEL (V
–
P-P
)
1360 G24
Total Harmonic Distortion
vs Frequency
0.01
TA = 25°C
= 3V
V
O
RMS
RL = 500Ω
0.001
TOTAL HARMONIC DISTORTION (%)
0.0001
8
10
AV = –1
AV = 1
100 100k
FREQUENCY (Hz)
1k
10k
1360 G25
Undistorted Output Swing vs
Frequency (±15V)
30
25
)
P-P
20
15
10
VS = ±15V
OUTPUT VOLTAGE (V
= 1k
R
L
5
= 1, 1% MAX DISTORTION
A
V
= –1, 2% MAX DISTORTION
A
V
0
100k 1M
FREQUENCY (Hz)
AV = 1
AV = –1
10M
1360 G26
Undistorted Output Swing vs
Frequency (±5V)
10
8
)
P-P
6
4
OUTPUT VOLTAGE (V
2
VS = ±5V
= 1k
R
L
2% MAX DISTORTION
0
100k 1M
FREQUENCY (Hz)
AV = –1
AV = 1
10M
1360 G27
Page 9
W
U
TYPICAL PERFORMANCE CHARACTERISTICS
LT1360
2nd and 3rd Harmonic Distortion
vs Frequency
–30
VS = ±15V
= 2V
V
O
–40
–50
–60
–70
HARMONIC DISTORTION (dB)
–80
–90
100k 200k 400k
P-P
RL = 500Ω
A
= 2
V
3RD HARMONIC
2ND HARMONIC
1M 2M 4M
FREQUENCY (Hz)
Small-Signal Transient
(AV = 1)
1360 G28
10M
Differential Gain and Phase
vs Supply Voltage
DIFFERENTIAL GAIN
0.40
0.36
0.32
DIFFERENTIAL PHASE (DEG)
0.28
DIFFERENTIAL PHASE
SUPPLY VOLTAGE (V)
Small-Signal Transient
(AV = –1)
AV = 2
= 150Ω
R
L
T
= 25°C
A
±10±5 ±15
1360 G29
DIFFERENTIAL GAIN (%)
0.50
0.25
0
Capacitive Load Handling
100
50
OVERSHOOT (%)
0
10p
Small-Signal Transient
(AV = –1, CL = 500pF)
VS = ±15V
= 25°C
T
A
1000p 0.01µ
100p 0.1µ
CAPACITIVE LOAD (F)
AV = –1
AV = 1
1µ
1360 G30
Large-Signal Transient
(AV = 1)
1360 TA31
1360 TA34
Large-Signal Transient
(AV = –1)
1360 TA32
1360 TA35
1360 TA33
Large-Signal Transient
(AV = 1, CL = 10,000pF)
1360 TA36
9
Page 10
LT1360
U
WUU
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
2
Layout and Passive Components
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.
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
+
–
1
LT1360
10k
7
6
4
8
–
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.
Cable Driver Frequency Response
2
0
–2
GAIN (dB)
–4
–6
–8
1
VS = ±2.5V
IN
+
LT1360
–
510Ω
75Ω
510Ω
FREQUENCY (MHz)
75Ω
10
AV = 2
= RG = 500Ω
R
F
= 150Ω
R
L
VS = ±15V
VS = ±10V
OUT
VS = ±5V
100
1360 AI02
CF > RG x CIN/R
F
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
Page 11
LT1360
U
WUU
APPLICATIONS INFORMATION
Input Considerations
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 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.
Power Dissipation
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:
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 P
P
Example: LT1360CS8 at 70°C, VS = ±15V, RL = 250W
P
T
= (V+ – V–)(I
DMAX
= (30V)(5.8mA) + (7.5V)2/250W = 399mW
DMAX
= 70°C + (399mW)(190°C/W) = 146°C
JMAX
) + (V+/2)2/R
SMAX
DMAX
is:
L
11
Page 12
LT1360
U
WUU
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
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.
12
Page 13
SI PLIFIED
+
V
LT1360
WW
SCHE ATIC
–IN
R1
500Ω
–
V
+IN
R
C
C
C
C
OUT
1360 SS01
13
Page 14
LT1360
PACKAGE DESCRIPTION
U
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
876
0.255 ± 0.015*
(6.477 ± 0.381)
5
12
0.300 – 0.325
(7.620 – 8.255)
0.065
(1.651)
0.009 – 0.015
(0.229 – 0.381)
+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)
TYP
0.045 – 0.065
(1.143 – 1.651)
0.100
(2.54)
BSC
3
4
0.130 ± 0.005
(3.302 ± 0.127)
0.125
(3.175)
MIN
0.018 ± 0.003
(0.457 ± 0.076)
0.020
(0.508)
MIN
N8 1098
14
Page 15
PACKAGE DESCRIPTION
U
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)
7
8
5
6
LT1360
0.228 – 0.244
(5.791 – 6.197)
0.010 – 0.020
(0.254 – 0.508)
0.008 – 0.010
(0.203 – 0.254)
*
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
×
°
45
0.016 – 0.050
(0.406 – 1.270)
0°– 8° TYP
0.053 – 0.069
(1.346 – 1.752)
0.014 – 0.019
(0.355 – 0.483)
TYP
0.150 – 0.157**
(3.810 – 3.988)
1
3
2
4
0.004 – 0.010
(0.101 – 0.254)
0.050
(1.270)
BSC
SO8 1298
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.
15
Page 16
LT1360
TYPICAL APPLICATIONS
i
PD
SFH205
1µF
10k
–5V
U
Photodiode Preamp with AC Coupling Loop
1pF
1N5712
10k
1N5712
10k
f
–
LT1360
+
300pF
5.1k
–
1/2 LT1358
+
±5V
VS =
100KHz, 5.5MHz
=
–3dB
2k
1/2 LT1358
–
+
2k
1360 TA03
V
OUT
1MHz, 4th Order Butterworth Filter
909Ω
47pF
V
IN
2.67k909Ω
220pF
–
LT1360
+
1.1k
2.21k
470pF
1.1k
–
22pF
LT1360
V
OUT
+
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
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear-tech.com
1360fa LT/TP 0400 2K REV A • PRINTED IN USA
LINEAR TECHNOLOGY CORPORATION 1994
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