LT1206_07 [Linear]
250mA/60MHz Current Feedback Amplifi er; 250毫安/ 60MHz的电流反馈功率放大器儿
| 型号： | LT1206_07 |
| 厂家： | 
Linear |
| 描述： | 250mA/60MHz Current Feedback Amplifi er |
| 文件： | 总16页 (文件大小：317K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LT1206
250mA/60MHz Current
Feedback Amplifier
FEATURES
DESCRIPTION
The LT®1206 is a current feedback amplifier with high
output current drive capability and excellent video char-
acteristics. The LT1206 is stable with large capacitive
loads, and can easily supply the large currents required
by the capacitive loading. A shutdown feature switches
the device into a high impedance, low current mode,
reducing dissipation when the device is not in use. For
lower bandwidth applications, the supply current can be
reducedwithasingleexternalresistor.Thelowdifferential
gain and phase, wide bandwidth, and the 250mA mini-
mum output current drive make the LT1206 well suited
to drive multiple cables in video systems.
■
250mA Minimum Output Drive Current
■
60MHz Bandwidth, A = 2, R = 100Ω
V
V
L
L
■
■
■
■
■
■
■
■
■
900V/µs Slew Rate, A = 2, R = 50Ω
0.02% Differential Gain, A = 2, R = 30Ω
V
V
L
L
0.17° Differential Phase, A = 2, R = 30Ω
High Input Impedance, 10MΩ
Wide Supply Range, 5V to 15V
Shutdown Mode: I < 200µA
S
Adjustable Supply Current
Stable with C = 10,000p
L
Available in 8-Pin DIP and SO and 7-Pin DD and
TO-220 Packages
The LT1206 is manufactured on Linear Technology’s
proprietary complementary bipolar process.
APPLICATIONS
■
Video Amplifiers
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
■
Cable Drivers
■
RGB Amplifiers
Test Equipment Amplifiers
■
■
Buffers
TYPICAL APPLICATION
Noninverting Amplifier with Shutdown
Large-Signal Response, CL = 10,000pF
15V
V
+
IN
V
LT1206 COMP
OUT
S/D**
C
–
COMP
0.01µF*
–15V
R
R
F
15V
*OPTIONAL, USE WITH CAPACITIVE LOADS
**GROUND SHUTDOWN PIN FOR
NORMAL OPERATION
G
5V
24k
ENABLE
74C906
1206 TA02
LT1206 • TA01
V
R
R
=
15V
G
500ns/DIV
S
L
L
= R = 3k
= ∞
1206fa
1
LT1206
(Note 1)
ABSOLUTE MAXIMUM RATINGS
Operating Temperature Range ................. –40°C to 85°C
Junction Temperature ........................................... 150°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
Supply Voltage........................................................ 18V
Input Current........................................................ 15mA
Output Short-Circuit Duration (Note 2) .........Continuous
Specified Temperature Range (Note 3) ........ 0°C to 70°C
PACKAGE/OERDER INFORMATION
TOP VIEW
TOP VIEW
+
+
+
NC
–IN
1
2
3
4
V
V
1
2
3
4
8
7
6
5
V
8
7
6
5
OUT
–IN
+IN
OUT
–
–
+IN
V
V
S/D*
COMP
S/D*
COMP
N8 PACKAGE
8-LEAD PLASTIC DIP
= 100°C/W
S8 PACKAGE
8-LEAD PLASTIC SO
= 60°C/W
θ
θ
JA
JA
ORDER PART NUMBER
ORDER PART NUMBER
LT1206CS8**
S8 PART MARKING
1206
LT1206CN8**
FRONT VIEW
FRONT VIEW
OUT
V
OUT
V
7
6
5
4
3
2
1
7
6
5
4
3
2
1
–
–
COMP
COMP
+
+
V
V
S/D*
+IN
–IN
S/D*
+IN
–IN
TAB IS
TAB IS
+
+
V
V
T7 PACKAGE
7-LEAD PLASTIC TO-220
= 5°C/W
R PACKAGE
7-LEAD PLASTIC DD
= 30°C/W
θ
θ
JA
JA
ORDER PART NUMBER
LT1206CR**
ORDER PART NUMBER
LT1206CT7**
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges. *Ground shutdown pin for normal operation. ** See Note 3.
ELECTRICAL CHARACTERISTICS The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T = 25°C. V = 0, 5V ꢀ V ꢀ 15V, pulse tested, V = 0V, unless otherwise noted.
A
CM
S
S/D
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
Input Offset Voltage
3
10
15
mV
mV
µV/°C
OS
●
●
Input Offset Voltage Drift
Noninverting Input Current
10
2
+
I
I
8
25
60
100
µA
µA
µA
µA
IN
●
●
–
Inverting Input Current
10
IN
1206fa
2
LT1206
ELECTRICAL CHARACTERISTICS The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T = 25°C. V = 0, 5V ꢀ V ꢀ 15V, pulse tested, V = 0V, unless otherwise noted.
A
CM
S
S/D
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
e
n
Input Noise Voltage Density
f = 10kHz, R = 1k, R = 10Ω, R = 0Ω
3.6
nV/√Hz
F
G
S
+i
–i
Input Noise Current Density
Input Noise Current Density
Input Resistance
f = 10kHz, R = 1k, R = 10Ω, R = 10k
2
pA/√Hz
pA/√Hz
n
F
G
S
f = 10kHz, R = 1k, R = 10Ω, R = 10k
30
n
F
G
S
●
●
R
V
IN
V
IN
=
=
12V, V = 15V
1.5
0.5
10
5
MΩ
MΩ
IN
S
2V, V = 5V
S
C
Input Capacitance
V = 15V
S
2
pF
IN
●
●
Input Voltage Range
V = 15V
S
12
2
13.5
3.5
V
V
S
V = 5V
●
●
CMRR
PSRR
Common Mode Rejection Ratio
V = 15V, V
S
=
=
12V
2V
12V
2V
55
50
62
60
0.1
0.1
dB
dB
µA/V
µA/V
S
CM
V = 5V, V
=
CM
●
●
Inverting Input Current Common Mode
Rejection
Power Supply Rejection Ratio
V = 15V, V
10
10
S
S
CM
V = 5V, V
=
CM
●
●
V = 5V to 15V
S
60
77
dB
Noninverting Input Current Power Supply V = 5V to 15V
Rejection
Inverting Input Current Power Supply
Rejection
30
500
5
nA/V
S
●
V = 5V to 15V
S
0.7
µA/V
●
●
A
Large-Signal Voltage Gain
V = 15V, V
=
10V, R = 50Ω
55
55
100
75
71
68
260
200
dB
dB
kΩ
kΩ
V
S
OUT
L
V = 5V, V
=
2V, R = 25Ω
S
OUT
L
–
●
●
R
Transresistance, ΔV /ΔI
V = 15V, V
=
10V, R = 50Ω
OL
OUT IN
S
OUT
L
V = 5V, V
S
= 2V, R = 25Ω
OUT
L
V
OUT
Maximum Output Voltage Swing
V = 15V, R = 50Ω
11.5
10.0
12.5
V
V
S
L
●
V = 15V, R = 25Ω
2.5
2.0
250
3.0
V
V
mA
S
L
●
●
I
I
Maximum Output Current
Supply Current
R = 1Ω
L
500
20
1200
OUT
V = 15V, V = 0V
30
35
mA
mA
S
S
S/D
●
Supply Current, R = 51k (Note 4)
V = 15V
12
17
200
10
mA
S/D
S
●
●
Positive Supply Current, Shutdown
Output Leakage Current, Shutdown
Slew Rate (Note 5)
V = 15V, V = 15V
S S/D
µA
V = 15V, V = 15V
S
µA
S/D
SR
A = 2
V
400
900
0.02
0.17
60
V/µs
%
Differential Gain (Note 6)
Differential Phase (Note 6)
Small-Signal Bandwidth
V = 15V, R = 560Ω, R = 560Ω, R = 30Ω
S F G L
V = 15V, R = 560Ω, R = 560Ω, RL = 30Ω
S
Deg
MHz
F
G
BW
V = 15V, Peaking ≤ 0.5dB,
S
R = R = 620Ω, R = 100Ω
F
G
L
V = 15V, Peaking ≤ 0.5dB,
52
43
27
MHz
MHz
MHz
S
R = R = 649Ω, R = 50Ω
F
G
L
V = 15V, Peaking ≤ 0.5dB,
S
R = R = 698Ω, R = 30Ω
F
G
L
V = 15V, Peaking ≤ 0.5dB,
S
R = R = 825Ω, R = 10Ω
F
G
L
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: Applies to short circuits to ground only. A short circuit between
the output and either supply may permanently damage the part when
operated on supplies greater than 10V.
Note 3: Commercial grade parts are designed to operate over the
temperature range of –40°C to 85°C but are neither tested nor guaranteed
beyond 0°C to 70°C. Industrial grade parts tested over –40°C to 85°C are
available on special request. Consult factory.
Note 4: R is connected between the shutdown pin and ground.
S/D
Note 5: Slew rate is measured at 5V on a 10V output signal while
operating on 15V supplies with R = 1.5k, R = 1.5k and R = 400Ω.
F
G
L
Note 6: NTSC composite video with an output level of 2V.
1206fa
3
LT1206
SMALL-SIGNAL BANDWIDTH
I = 20mA Typical, Peaking ꢀ 0.1dB
S
–3dB BW
(MHz)
–0.1dB BW
(MHz)
–3dB BW
(MHz)
–0.1dB BW
(MHz)
A
V
R
R
F
R
G
A
V
R
L
R
F
R
G
L
V = 5V, R = 0Ω
V = 15V, R = 0Ω
S S/D
S
S/D
–1
1
150
562
649
732
562
649
732
48
34
22
21.4
17
–1
1
150
681
768
887
681
768
887
50
35
24
19.2
17
30
10
30
10
12.5
12.3
150
30
10
619
715
806
–
–
–
54
36
22.4
22.3
17.5
11.5
150
30
10
768
909
1k
–
–
–
66
37
23
22.4
17.5
12
2
150
30
10
576
649
750
576
649
750
48
35
22.4
20.7
18.1
11.7
2
150
30
10
665
787
931
665
787
931
55
36
22.5
23
18.5
11.8
10
150
30
10
442
511
649
48.7
56.2
71.5
40
31
20
19.2
16.5
10.2
10
150
30
10
487
590
768
536
64.9
84.5
44
33
20.7
20.7
17.5
10.8
I = 10mA Typical, Peaking ꢀ 0.1dB
S
–3dB BW
(MHz)
–0.1dB BW
(MHz)
–3dB BW
(MHz)
–0.1dB BW
(MHz)
A
V
R
R
F
R
G
A
V
R
L
R
F
R
G
L
V = 5V, R = 10.2k
V = 15V, R = 60.4k
S S/D
S
S/D
–1
1
150
576
681
750
576
681
750
35
25
17
12.5
8.7
–1
1
150
634
768
866
634
768
866
41
26.5
17
19.1
14
30
10
30
10
16.4
9.4
150
30
10
665
768
845
–
–
–
37
25
16.5
17.5
12.6
8.2
150
30
10
768
909
1k
–
–
–
44
28
16.8
18.8
14.4
8.3
2
150
30
10
590
681
768
590
681
768
35
25
16.2
16.8
13.4
8.1
2
150
30
10
649
787
931
649
787
931
40
27
16.5
18.5
14.1
8.1
10
150
30
10
301
392
499
33.2
43.2
54.9
31
23
15
15.6
11.9
7.8
10
150
30
10
301
402
590
33.2
44.2
64.9
33
25
15.3
15.6
13.3
7.4
I = 5mA Typical, Peaking ꢀ 0.1dB
S
–3dB BW
(MHz)
–0.1dB BW
(MHz)
–3dB BW
(MHz)
–0.1dB BW
(MHz)
A
V
R
R
F
R
G
A
V
R
L
R
F
R
G
L
V = 5V, R = 22.1k
V = 15V, R = 121k
S S/D
S
S/D
–1
1
150
604
715
681
604
715
681
21
10.5
7.4
–1
1
150
619
787
825
619
787
825
25
12.5
8.5
30
10
14.6
10.5
30
10
15.8
10.5
6.0
5.4
150
30
10
768
866
825
–
–
–
20
14.1
9.8
9.6
6.7
5.1
150
30
10
845
1k
1k
–
–
–
23
15.3
10
10.6
7.6
5.2
2
150
30
10
634
750
732
634
750
732
20
14.1
9.6
9.6
7.2
5.1
2
150
30
10
681
845
866
681
845
866
23
15
10
10.2
7.7
5.4
10
150
30
10
100
100
100
11.1
11.1
11.1
16.2
13.4
9.5
5.8
7.0
4.7
10
150
30
10
100
100
100
11.1
11.1
11.1
15.9
13.6
9.6
4.5
6
4.5
1206fa
4
LT1206
TYPICAL PERFORMANCE CHARACTERISTICS
Bandwidth and Feedback Resistance
Bandwidth vs Supply Voltage
vs Capacitive Load for 0.5dB Peak
Bandwidth vs Supply Voltage
10k
100
10
1
100
90
80
70
60
50
40
30
20
10
0
50
40
30
20
10
0
A
= 2
= 100Ω
BANDWIDTH
PEAKING ≤ 0.5dB
PEAKING ≤ 5dB
PEAKING ≤ 0.5dB
PEAKING ≤ 5dB
A
= 2
= 10Ω
V
L
V
L
R
R
R
= 560Ω
= 750Ω
F
F
R
= 470Ω
F
R
= 560Ω
F
R
R
= 680Ω
F
1k
R
= 1k
F
R
= 750Ω
F
FEEDBACK RESISTOR
R
= 2k
F
A
= 2
V
L
S
R
= 1k
F
R
= ∞
V
C
= 15V
COMP
R
= 1.5k
16
F
= 0.01µF
100
1
10
100
1000
10000
4
12
14
4
16
6
8
10
18
6
8
10
12
14
18
CAPACITIVE LOAD (pF)
SUPPLY VOLTAGE ( V)
SUPPLY VOLTAGE ( V)
LT1206 • TPC03
LT1206 • TPC01
LT1206 • TPC02
Bandwidth and Feedback Resistance
vs Capacitive Load for 5dB Peak
Bandwidth vs Supply Voltage
Bandwidth vs Supply Voltage
100
90
80
70
60
50
40
30
20
10
0
50
40
30
20
10
0
10k
100
A
= 10
= 100Ω
PEAKING ≤ 0.5dB
PEAKING ≤ 5dB
A
= 10
= 10Ω
PEAKING ≤ 0.5dB
PEAKING ≤ 5dB
V
L
V
L
BANDWIDTH
R
R
R
=390Ω
R
= 330Ω
R
R
= 560Ω
= 680Ω
F
F
F
1k
10
F
R
R
= 470Ω
= 680Ω
F
R
R
= 1k
F
A
= +2
F
V
L
S
FEEDBACK RESISTOR
= 1.5k
R
= ∞
F
V
C
=
15V
= 0.01µF
R
= 1.5k
F
COMP
100
1
10k
4
12
14
16
16
6
8
10
18
4
12
14
6
8
10
18
1
10
100
1k
CAPACITIVE LOAD (pF)
SUPPLY VOLTAGE ( V)
SUPPLY VOLTAGE ( V)
LT1206 • TPC04
LT1206 • TPC05
LT1206 • TPC06
Differential Phase
vs Supply Voltage
Differential Gain
vs Supply Voltage
Spot Noise Voltage and Current
vs Frequency
100
10
1
0.50
0.40
0.30
0.10
0.08
0.06
R
V
= R = 560Ω
F
G
A
= 2
R
R
= 15Ω
= 30Ω
L
R
= 15Ω
= 30Ω
N PACKAGE
L
L
–i
n
R
A
= R = 560Ω
F
V
G
R
= 2
N PACKAGE
0.20
0.10
0
0.04
0.02
0
L
R
= 50Ω
L
e
i
n
R
R
= 50Ω
L
n
= 150Ω
L
R
7
= 150Ω
L
10
100
1k
FREQUENCY (Hz)
10k
100k
5
7
9
11
13
15
5
9
11
13
15
SUPPLY VOLTAGE ( V)
SUPPLY VOLTAGE ( V)
LT1206 • TPC09
LT1206 • TPC07
LT1206 • TPC08
1206fa
5
LT1206
TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current vs Ambient
Supply Current vs Ambient
Temperature, V = 15V
Supply Current vs Supply Voltage
Temperature, V = 5V
S
S
24
22
20
25
20
15
10
5
25
20
15
10
5
V
= 0V
A
= 1
A
= 1
V
S/D
V
L
T = –40˚C
R
= 0Ω
J
R
= ∞
R
= ∞
L
SD
R
= 0Ω
SD
N PACKAGE
N PACKAGE
T = 25˚C
J
18
16
14
R
R
= 10.2k
= 22.1k
R
R
= 60.4k
= 121k
SD
SD
SD
T = 85˚C
J
SD
T = 125˚C
J
12
10
0
0
50
75 100 125
–50
–25
0
25
50
75 100 125
4
12
14
16
–50
–25
0
25
6
8
10
18
SUPPLY VOLTAGE ( V)
TEMPERATURE (°C)
TEMPERATURE (°C)
LT1206 • TPC10
LT1206 • TPC11
LT1206 • TPC12
Supply Current vs Shutdown Pin
Current
Input Common Mode Limit vs
Junction Temperature
Output Short-Circuit Current vs
Junction Temperature
+
V
1.0
0.9
20
18
16
14
12
10
8
V
= 15V
S
– 0.5
–1.0
–1.5
–2.0
2.0
0.8
0.7
0.6
0.5
0.4
SOURCING
SINKING
1.5
6
1.0
4
0.5
2
–
0.3
V
0
50
TEMPERATURE (°C)
100 125
–50 –25
0
25
75
0
100
200
300
400
500
–50 –25
0
100 125
25
50
75
TEMPERATURE (°C)
SHUTDOWN PIN CURRENT (µA)
LT1206 • TPC15
LT1206 • TPC13
LT1206 • TPC14
Output Saturation Voltage vs
Junction Temperature
Power Supply Rejection Ratio vs
Frequency
Supply Current vs Large-Signal
Output Frequency (No Load)
+
V
60
50
40
30
20
10
70
60
50
40
30
20
10
0
A
= 2
V
= 15V
V
L
S
S
R
= 2k
R
V
= 50Ω
L
L
S
F
–1
–2
–3
–4
4
R
= ∞
=
15V
NEGATIVE
POSITIVE
V
V
=
15V
= 20V
R
= R = 1k
G
OUT
P-P
R
= 50Ω
L
R
R
= 50Ω
L
L
3
2
= 2k
1
–
V
10k
100k
1M
10M
10k
100k
1M
10M
100M
–50 –25
0
100 125
25
50
75
FREQUENCY (Hz)
TEMPERATURE (°C)
FREQUENCY (Hz)
LT1206 • TPC17
LT1206 • TPC18
LT1206 • TPC16
1206fa
6
LT1206
TYPICAL PERFORMANCE CHARACTERISTICS
Output Impedance in Shutdown vs
Frequency
2nd and 3rd Harmonic Distortion
vs Frequency
Output Impedance vs Frequency
–30
–40
–50
–60
–70
–80
–90
100
10
100k
10k
V
V
=
15V
P-P
V
I
=
15V
S
O
A
= 1
S
O
V
F
S
= 2V
= 0mA
R
= 1k
V
= 15V
R
= 121k
2nd
S/D
R
= 10Ω
L
3rd
2nd
R
= 0Ω
S/D
1
1k
R
= 30Ω
L
3rd
0.1
100
0.01
100k
10
100k
1
2
3
4
5
6 7 8 9 10
1M
10M
100M
1M
10M
100M
FREQUENCY (MHz)
FREQUENCY (Hz)
FREQUENCY (Hz)
LT1206 • TPC21
LT1206 • TPC19
LT1206 • TPC20
3rd Order Intercept vs Frequency
Test Circuit for 3rd Order Intercept
60
50
40
30
V
= 15V
S
L
F
R
R
R
= 50Ω
+
= 590Ω
= 64.9Ω
P
LT1206
O
G
–
590Ω
50Ω
65Ω
MEASURE INTERCEPT AT P
O
LT1206 • TPC23
20
10
0
10
15
20
25
30
5
FREQUENCY (MHz)
LT1206 • TPC22
1206fa
7
LT1206
SIMPLIFIED SCHEMATIC
+
V
TO ALL
CURRENT
SOURCES
Q5
Q10
Q2
D1
Q11
Q6
Q15
Q18
Q1
Q17
Q9
–
–
V
1.25k
+IN
50Ω
COMP
V
C
C
–IN
R
C
OUTPUT
+
V
SHUTDOWN
+
V
Q12
Q3
Q8
Q16
Q14
D2
Q4
Q13
Q7
–
V
LT1206 • SS
APPLICATIONS INFORMATION
TheLT1206isacurrentfeedbackamplifierwithhighoutput
current drive capability. The device is stable with large
capacitive loads and can easily supply the high currents
required by capacitive loads. The amplifier will drive low
impedance loads such as cables with excellent linearity
at high frequencies.
line when the response has 0.5dB to 5dB of peaking. The
curves stop where the response has more than 5dB of
peaking.
For resistive loads, the COMP pin should be left open (see
section on capacitive loads).
Capacitive Loads
Feedback Resistor Selection
The LT1206 includes an optional compensation network
for driving capacitive loads. This network eliminates most
of the output stage peaking associated with capacitive
loads, allowing the frequency response to be flattened.
Figure 1 shows the effect of the network on a 200pF load.
Without the optional compensation, there is a 5dB peak
at 40MHz caused by the effect of the capacitance on the
outputstage.Addinga0.01µFbypasscapacitorbetweenthe
outputandtheCOMPpinsconnectsthecompensationand
completelyeliminatesthepeaking. Alowervaluefeedback
resistor can now be used, resulting in a response which
The optimum value for the feedback resistors is a function
of the operating conditions of the device, the load imped-
ance and the desired flatness of response. The Typical AC
Performance tables give the values which result in the
highest 0.1dB and 0.5dB bandwidths for various resistive
loads and operating conditions. If this level of flatness is
not required, a higher bandwidth can be obtained by use
of a lower feedback resistor. The characteristic curves of
Bandwidth vs Supply Voltage indicate feedback resistors
for peaking up to 5dB. These curves use a solid line when
the response has less than 0.5dB of peaking and a dashed
1206fa
8
LT1206
APPLICATIONS INFORMATION
12
capacitor and the supply current is typically 100µA. The
shutdown pin is referenced to the positive supply through
an internal bias circuit (see the simplified schematic). An
easy way to force shutdown is to use open drain (collec-
tor) logic. The circuit shown in Figure 2 uses a 74C904
buffer to interface between 5V logic and the LT1206. The
switching time between the active and shutdown states
is less than 1µs. A 24k pull-up resistor speeds up the
turn-off time and insures that the LT1206 is completely
turned off. Because the pin is referenced to the positive
supply, the logic used should have a breakdown voltage
of greater than the positive supply voltage. No other
circuitry is necessary as the internal circuit limits the
shutdown pin current to about 500µA. Figure 3 shows
the resulting waveforms.
V
= 15V
S
10
8
R
= 1.2k
F
COMPENSATION
6
4
2
R = 2k
F
NO COMPENSATION
0
R
= 2k
F
–2
–4
–6
–8
COMPENSATION
1
10
100
FREQUENCY (MHz)
LT1206 • F01
Figure 1
is flat to 0.35dB to 30MHz. The network has the greatest
effect for C in the range of 0pF to 1000pF. The graph of
L
15V
Maximum Capacitive Load vs Feedback Resistor can be
used to select the appropriate value of feedback resistor.
The values shown are for 0.5dB and 5dB peaking at a gain
of 2 with no resistive load. This is a worst case condition,
as the amplifier is more stable at higher gains and with
some resistive load in parallel with the capacitance. Also
shownisthe–3dBbandwidthwiththesuggestedfeedback
resistor vs the load capacitance.
V
+
IN
V
LT1206
OUT
S/D
–
–15V
R
R
F
15V
24k
G
5V
Although the optional compensation works well with ca-
pacitive loads, it simply reduces the bandwidth when it is
connected with resistive loads. For instance, with a 30Ω
load,thebandwidthdropsfrom55MHzto35MHzwhenthe
compensationisconnected.Hence,thecompensationwas
made optional. To disconnect the optional compensation,
leave the COMP pin open.
ENABLE
LT1206 • F02
74C906
Figure 2. Shutdown Interface
Shutdown/Current Set
V
OUT
If the shutdown feature is not used, the SHUTDOWN pin
–
must be connected to ground or V .
The shutdown pin can be used to either turn off the bias-
ing for the amplifier, reducing the quiescent current to
less than 200µA, or to control the quiescent current in
normal operation.
ENABLE
1206 F03
A
= 1
1µs/DIV
V
F
L
R
R
R
= 825Ω
= 50Ω
ThetotalbiascurrentintheLT1206iscontrolledbythecur-
rent flowing out of the shutdown pin. When the shutdown
pin is open or driven to the positive supply, the part is shut
down. In the shutdown mode, the output looks like a 40pF
= 24k
PU
= 1V
IN
V
P-P
Figure 3. Shutdown Operation
1206fa
9
LT1206
APPLICATIONS INFORMATION
For applications where the full bandwidth of the amplifier
is not required, the quiescent current of the device may be
reduced by connecting a resistor from the shutdown pin
to ground. The quiescent current will be approximately 40
Slew Rate
Unlike a traditional op amp, the slew rate of a current
feedback amplifier is not independent of the amplifier gain
configuration. There are slew rate limitations in both the
input stage and the output stage. In the inverting mode,
and for higher gains in the noninverting mode, the signal
amplitude on the input pins is small and the overall slew
rate is that of the output stage. The input stage slew rate
is related to the quiescent current and will be reduced as
the supply current is reduced. The output slew rate is set
by the value of the feedback resistors and the internal
capacitance.Largerfeedbackresistorswillreducetheslew
rate as will lower supply voltages, similar to the way the
bandwidth is reduced. The photos (Figures 5a, 5b and 5c)
show the large-signal response of the LT1206 for various
gain configurations. The slew rate varies from 860V/µs
for a gain of 1, to 1400V/µs for a gain of –1.
times the current in the shutdown pin. The voltage across
+
the resistor in this condition is V – 3V . For example, a
BE
60k resistor will set the quiescent supply current to 10mA
with V = 15V.
S
Thephotos(Figures4aand4b)showtheeffectofreducing
thequiescentsupplycurrentonthelarge-signalresponse.
Thequiescentcurrentcanbereducedto5mAintheinvert-
ing configuration without much change in response. In
noninverting mode, however, the slew rate is reduced as
the quiescent current is reduced.
1206 F04a
R
R
= 750Ω
50ns/DIV
F
L
= 50Ω
I
= 5mA, 10mA, 20mA
= 15V
Q
V
S
1206 F05a
R
R
= 825Ω
= 50Ω
= 15V
20ns/DIV
F
L
S
Figure 4a. Large-Signal Response vs I , A = –1
Q
V
V
Figure 5a. Large-Signal Response, A = 1
V
1206 F04b
R
R
= 750Ω
50ns/DIV
F
L
= 50Ω
I
= 5mA, 10mA, 20mA
= 15V
Q
1206 F05b
V
S
R
R
V
= R = 750Ω
20ns/DIV
F
L
S
G
= 50Ω
Figure 4b. Large-Signal Response vs I , A = 2
=
15V
Q
V
Figure 5a. Large-Signal Response, A = –1
V
1206fa
10
LT1206
APPLICATIONS INFORMATION
the maximum allowable input voltage. To allow for some
margin, it is recommended that the input signal be less
than 5V when the device is shut down.
Capacitance on the Inverting Input
Currentfeedbackamplifiersrequireresistivefeedbackfrom
the output to the inverting input for stable operation. Take
care to minimize the stray capacitance between the output
and the inverting input. Capacitance on the inverting input
to ground will cause peaking in the frequency response
(and overshoot in the transient response), but it does not
degrade the stability of the amplifier.
1206 F05c
R
R
= 750Ω
= 50Ω
20ns/DIV
F
L
Figure 5c. Large-Signal Response, A = 2
V
Power Supplies
When the LT1206 is used to drive capacitive loads, the
availableoutputcurrentcanlimittheoverallslewrate.Inthe
fastest configuration, the LT1206 is capable of a slew rate
of over 1V/ns. The current required to slew a capacitor at
this rate is 1mA per picofarad of capacitance, so 10,000pF
would require 10A! The photo (Figure 6) shows the large
The LT1206 will operate from single or split supplies from
5V (10V total) to 15V (30V total). It is not necessary to
use equal value split supplies, however the offset voltage
and inverting input bias current will change. The offset
voltagechangesabout500µVpervoltofsupplymismatch.
The inverting bias current can change as much as 5µA
per volt of supply mismatch, though typically the change
is less than 0.5µA per volt.
signal behavior with C = 10,000pF. The slew rate is about
L
60V/µs, determined by the current limit of 600mA.
Thermal Considerations
The LT1206 contains a thermal shutdown feature which
protectsagainstexcessiveinternal(junction)temperature.
If the junction temperature of the device exceeds the pro-
tection threshold, the device will begin cycling between
normal operation and an off state. The cycling is not
harmful to the part. The thermal cycling occurs at a slow
rate, typically 10ms to several seconds, which depends
on the power dissipation and the thermal time constants
of the package and heat sinking. Raising the ambient
temperature until the device begins thermal shutdown
gives a good indication of how much margin there is in
the thermal design.
1206 TA02
V
R
R
=
15V
G
500ns/DIV
S
L
L
= R = 3k
= ∞
Figure 6. Large-Signal Response, C = 10,000pF
L
For surface mount devices heat sinking is accomplished
by using the heat spreading capabilities of the PC board
and its copper traces. Experiments have shown that the
heat spreading copper layer does not need to be electri-
cally connected to the tab of the device. The PCB material
can be very effective at transmitting heat between the pad
area attached to the tab of the device, and a ground or
1206fa
Differential Input Signal Swing
The differential input swing is limited to about 6V by
an ESD protection device connected between the inputs.
In normal operation, the differential voltage between the
input pins is small, so this clamp has no effect; however,
in the shutdown mode the differential swing can be the
same as the input swing. The clamp voltage will then set
11
LT1206
APPLICATIONS INFORMATION
Calculating Junction Temperature
power plane layer either inside or on the opposite side of
the board. Although the actual thermal resistance of the
PCB material is high, the length/area ratio of the thermal
resistancebetweenthelayerissmall.Copperboardstiffen-
ers and plated through holes can also be used to spread
the heat generated by the device.
The junction temperature can be calculated from the
equation:
T = (P × θ ) + T
J
D
JA
A
where:
Tables 1 and 2 list thermal resistance for each package.
For the TO-220 package, thermal resistance is given for
junction-to-caseonlysincethispackageisusuallymounted
to a heat sink. Measured values of thermal resistance for
several different board sizes and copper areas are listed
for each surface mount package. All measurements were
taken in still air on 3/32" FR-4 board with 1oz copper. This
datacanbeusedasaroughguidelineinestimatingthermal
resistance.Thethermalresistanceforeachapplicationwill
beaffectedbythermalinteractionswithothercomponents
as well as board size and shape.
T = Junction Temperature
J
T = Ambient Temperature
A
P = Device Dissipation
D
θ
= Thermal Resistance (Junction-to Ambient)
JA
As an example, calculate the junction temperature for the
circuitinFigure7fortheN8,S8,andRpackagesassuming
a 70°C ambient temperature.
15V
39mA
I
+
Table 1. R Package, 7-Lead DD
12V
LT1206
S/D
–
COPPER AREA
TOPSIDE* BACKSIDE
THERMAL RESISTANCE
330Ω
–12V
f = 2MHz
0.01µF
BOARD AREA (JUNCTION-TO-AMBIENT)
2k
300pF
2500 sq. mm 2500 sq. mm 2500 sq. mm
1000 sq. mm 2500 sq. mm 2500 sq. mm
125 sq. mm 2500 sq. mm 2500 sq. mm
*Tab of device attached to topside copper
25°C/W
27°C/W
35°C/W
–15V
2k
LT1206 • F07
Figure 7. Thermal Calculation Example
Table 2. S8 Package, 8-Lead Plastic SO
COPPER AREA
The device dissipation can be found by measuring the
supply currents, calculating the total dissipation, and
then subtracting the dissipation in the load and feedback
network.
THERMAL RESISTANCE
TOPSIDE*
BACKSIDE
BOARD AREA (JUNCTION-TO-AMBIENT)
2500 sq. mm 2500 sq. mm 2500 sq. mm
1000 sq. mm 2500 sq. mm 2500 sq. mm
225 sq. mm 2500 sq. mm 2500 sq. mm
100 sq. mm 2500 sq. mm 2500 sq. mm
100 sq. mm 1000 sq. mm 2500 sq. mm
100 sq. mm 225 sq. mm 2500 sq. mm
100 sq. mm 100 sq. mm 2500 sq. mm
*Pins 1 and 2 attached to topside copper
60°C/W
62°C/W
65°C/W
69°C/W
73°C/W
80°C/W
83°C/W
2
P = (39mA × 30V) – (12V) /(2k||2k) = 1.03W
D
Then:
T = (1.03W × 100°C/W) + 70°C = 173°C
J
for the N8 package
T = (1.03W × 65°C/W) × + 70°C = 137°C
J
Y Package, 7-Lead TO-220
Thermal Resistance (Junction-to-Case) = 5°C/W
for the S8 with 225 sq. mm topside heat sinking
T = (1.03W × 35°C/W) × + 70°C = 106°C
J
N8 Package, 8-Lead DIP
Thermal Resistance (Junction-to-Ambient) = 100°C/W
for the R package with 100 sq. mm topside heat
sinking
Since the Maximum Junction Temperature is 150°C, the
N8 package is clearly unacceptable. Both the S8 and R
packages are usable.
1206fa
12
LT1206
TYPICAL APPLICATIONS
Precision ×10 Hi Current Amplifier
CMOS Logic to Shutdown Interface
15V
V
+
IN
LT1097
+
LT1206
COMP
S/D
+
OUT
–
24k
LT1206
S/D
–
0.01µF
–
500pF
LT1206 • TA05
330Ω
3k
5V
–15V
10k
2N3904
10k
LT1206 • TA03
OUTPUT OFFSET: < 500µV
SLEW RATE: 2V/µs
1k
BANDWIDTH: 4MHz
STABLE WITH C < 10nF
L
Low Noise ×10 Buffered Line Driver
Distribution Amplifier
15V
1µF
15V
1µF
V
+
–
IN
75Ω CABLE
+
75Ω
+
+
–
LT1206
S/D
75Ω
LT1115
+
–
75Ω
R
F
OUTPUT
LT1206
S/D
1µF
75Ω
+
0.01µF
R
L
LT1206 • TA06
–15V
R
G
1µF
75Ω
68pF
+
–15V
560Ω
909Ω
560Ω
LT1206 • TA04
100Ω
R
O
= 32Ω
= 5V
RMS
L
V
THD + NOISE = 0.0009% AT 1kHz
= 0.004% AT 20kHz
SMALL SIGNAL 0.1dB BANDWIDTH = 600kHz
Buffer A = 1
V
V
+
IN
LT1206
COMP
S/D
V
*OPTIONAL, USE WITH CAPACITIVE LOADS
OUT
**VALUE OF R DEPENDS ON SUPPLY
F
–
0.01µF*
VOLTAGE AND LOADING. SELECT
FROM TYPICAL AC PERFORMANCE
TABLE OR DETERMINE EMPIRICALLY
R **
F
LT1206 • TA07
1206fa
13
LT1206
PACKAGE DESCRIPTION
N8 Package
8-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510)
.400*
(10.160)
MAX
.130 .005
.045 – .065
.300 – .325
(3.302 0.127)
(1.143 – 1.651)
(7.620 – 8.255)
8
1
7
6
5
.065
(1.651)
TYP
.255 .015*
(6.477 0.381)
.008 – .015
(0.203 – 0.381)
.120
.020
(0.508)
MIN
(3.048)
MIN
+.035
–.015
2
4
3
.325
.018 .003
(0.457 0.076)
.100
(2.54)
BSC
N8 1002
+0.889
8.255
(
)
–0.381
NOTE:
INCHES
1. DIMENSIONS ARE
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
R Package
7-Lead Plastic DD Pak
(Reference LTC DWG # 05-08-1462)
.060
(1.524)
TYP
.390 – .415
(9.906 – 10.541)
.060
(1.524)
.256
(6.502)
.165 – .180
(4.191 – 4.572)
.045 – .055
(1.143 – 1.397)
15° TYP
.060
(1.524)
+.008
.004
.183
(4.648)
–.004
.059
(1.499)
TYP
.330 – .370
(8.382 – 9.398)
+0.203
–0.102
0.102
(
)
.095 – .115
(2.413 – 2.921)
.075
(1.905)
.300
(7.620)
.050
(1.27)
BSC
.050 .012
.013 – .023
(0.330 – 0.584)
+.012
.143
(1.270 0.305)
–.020
R (DD7) 0502
.026 – .035
(0.660 – 0.889)
TYP
BOTTOM VIEW OF DD PAK
HATCHED AREA IS SOLDER PLATED
COPPER HEAT SINK
+0.305
3.632
(
)
–0.508
.420
.276
.080
.420
.350
.325
.205
.320
.565
.565
.090
.035
.090
.035
.050
.050
RECOMMENDED SOLDER PAD LAYOUT
NOTE:
RECOMMENDED SOLDER PAD LAYOUT
FOR THICKER SOLDER PASTE APPLICATIONS
1. DIMENSIONS IN INCH/(MILLIMETER)
2. DRAWING NOT TO SCALE
1206fa
14
LT1206
PACKAGE DESCRIPTION
S8 Package
8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610)
.189 – .197
(4.801 – 5.004)
.045 .005
NOTE 3
.050 BSC
7
5
8
6
.245
MIN
.160 .005
.150 – .157
(3.810 – 3.988)
NOTE 3
.228 – .244
(5.791 – 6.197)
.030 .005
TYP
1
3
4
2
RECOMMENDED SOLDER PAD LAYOUT
.010 – .020
(0.254 – 0.508)
× 45°
.053 – .069
(1.346 – 1.752)
.004 – .010
(0.101 – 0.254)
.008 – .010
(0.203 – 0.254)
0°– 8° TYP
.016 – .050
(0.406 – 1.270)
.050
(1.270)
BSC
.014 – .019
(0.355 – 0.483)
TYP
NOTE:
INCHES
1. DIMENSIONS IN
(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)
SO8 0303
T7 Package
7-Lead Plastic TO-220 (Standard)
(Reference LTC DWG # 05-08-1422)
.165 – .180
(4.191 – 4.572)
.147 – .155
(3.734 – 3.937)
DIA
.390 – .415
(9.906 – 10.541)
.045 – .055
(1.143 – 1.397)
.230 – .270
(5.842 – 6.858)
.570 – .620
(14.478 – 15.748)
.620
(15.75)
TYP
.460 – .500
(11.684 – 12.700)
.330 – .370
(8.382 – 9.398)
.700 – .728
(17.780 – 18.491)
.095 – .115
(2.413 – 2.921)
.155 – .195*
(3.937 – 4.953)
SEATING PLANE
.152 – .202
(3.860 – 5.130)
.260 – .320
(6.604 – 8.128)
.013 – .023
(0.330 – 0.584)
.050
BSC
.026 – .036
(0.660 – 0.914)
(1.27)
.135 – .165
(3.429 – 4.191)
*MEASURED AT THE SEATING PLANE
T7 (TO-220) 0801
1206fa
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
15
LT1206
RELATED PARTS
PART NUMBER
LT1010
DESCRIPTION
COMMENTS
High Speed Buffer
High Power, High Speed Buffer
Adjustable Supply Current, Shutdown
Adjustable Supply Current, Shutdown
0.1dB Gain Flatness to 100MHz
S6 Version Features Programmable Supply Current
LT1207
Dual 250mA Out, 900V/µs, 60MHz Current Feedback Amplifier
1.1A, 35MHz, 900V/µs Current Feedback Amplifier
Single 400MHz Current Feedback Amplifier
LT1210
LT1395
LT1815
6.5mA, 220MHz, 1.5V/ns Operational Amplifier with
Programmable Current
LT1818
400MHz, 2500V/µs, 9mA Single Operational Amplifier
High Speed, Low Noise, Low Distortion, Low Offset
1206fa
LT 0307 REV A • PRINTED IN USA
16 LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
●
●
© LINEAR TECHNOLOGY CORPORATION 1993
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
相关型号：
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