LT1210CS [Linear]
1.1A, 35MHz Current Feedback Amplifier; 1.1A ， 35MHz时电流反馈放大器
| 型号： | LT1210CS |
| 厂家： | 
Linear |
| 描述： | 1.1A, 35MHz Current Feedback Amplifier |
| 文件： | 总16页 (文件大小：362K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LT1210
1.1A, 35MHz Current
Feedback Amplifier
U
DESCRIPTIO
EATURE
S
F
The LT®1210 is a current feedback amplifier with high
output current and excellent large-signal characteristics.
The combination of high slew rate, 1.1A output drive and
±15V operation enables the device to deliver significant
power at frequencies in the 1MHz to 2MHz range. Short-
circuit protection and thermal shutdown ensure the
device’s ruggedness. The LT1210 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 and low
supply current mode, reducing dissipation when the
device is not in use. For lower bandwidth applications,
the supply current can be reduced with a single external
resistor.
■
■
■
■
■
1.1A Minimum Output Drive Current
35MHz Bandwidth, AV = 2, RL = 10
900V/ s Slew Rate, AV = 2, RL = 10
High Input Impedance: 10MΩ
Wide Supply Range: ±5V to ±15V
(TO-220 and DD Packages)
Enhanced θJA SO-16 Package for ±5V Operation
Shutdown Mode: IS < 200µA
Adjustable Supply Current
Stable with CL = 10,000pF
Ω
Ω
µ
■
■
■
■
U
APPLICATIONS
■
Cable Drivers
Buffers
Test Equipment Amplifiers
Video Amplifiers
ADSL Drivers
■
The LT1210 is available in the TO-220 and DD packages
for operation with supplies up to ±15V. For ±5V applica-
tions the device is also available in a low thermal resis-
tance SO-16 package.
■
■
■
, LTC and LT are registered trademarks of Linear Technology Corporation.
U
TYPICAL APPLICATIO S
Twisted Pair Driver
Total Harmonic Distortion vs Frequency
15V
–50
+
V
V
A
= ±15V
OUT
= 4
S
100nF
4.7µF*
= 20V
P-P
–60
–70
V
R
T
11Ω
V
+
IN
2.5W
T1**
LT1210
SD
R
= 12.5Ω
= 10Ω
L
R
L
–
R
100Ω
L
1
3
–80
2.5W
R
= 50Ω
L
4.7µF*
100nF
+
–90
845Ω
274Ω
–15V
* TANTALUM
** MIDCOM 671-7783 OR EQUIVALENT
–100
1k
10k
100k
1M
FREQUENCY (Hz)
1210 TA01
1210 TA02
1
LT1210
W W W
U
ABSOLUTE AXI U RATI GS
Supply Voltage ..................................................... ±18V
Input Current .................................................... ±15mA
Output Short-Circuit Duration (Note 1) ....... Continuous
Specified Temperature Range (Note 2) ...... 0°C to 70°C
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
U
W U
PACKAGE/ORDER INFORMATION
TOP VIEW
+
+
+
V
V
1
2
3
4
5
6
7
8
16
V
15
14
13
12
11
10
9
NC
–
FRONT VIEW
FRONT VIEW
OUT
+
V
7
6
5
4
3
2
1
OUT
7
6
5
4
3
2
1
OUT
–
–
V
V
V
COMP
SHUTDOWN
+IN
COMP
COMP
+
+
V
V
NC
–IN
NC
SHUTDOWN
+IN
SHUTDOWN
+IN
TAB
TAB
+
+
IS V
IS V
–IN
–IN
NC
+
R PACKAGE
7-LEAD PLASTIC DD
T7 PACKAGE
7-LEAD TO-220
+
V
V
S PACKAGE
16-LEAD PLASTIC SO
θJC = 5°C/W
θJA ≈ 25°C/W
θJA ≈ 40°C/W (Note 3)
ORDER PART NUMBER
ORDER PART NUMBER
LT1210CT7
ORDER PART NUMBER
LT1210CS
LT1210CR
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
VCM = 0V, ±5V ≤ VS ≤ ±15V, pulse tested, VSD = 0V, unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
T = 25°C
MIN
TYP
MAX
UNITS
V
OS
Input Offset Voltage
±3
±15
±20
mV
mV
A
●
●
Input Offset Voltage Drift
Noninverting Input Current
10
µV/°C
+
I
I
T = 25°C
A
±2
±5
±20
µA
µA
IN
●
●
–
Inverting Input Current
T = 25°C
A
±10
±60
±100
µA
µA
IN
e
Input Noise Voltage Density
Input Noise Current Density
Input Noise Current Density
Input Resistance
f = 10kHz, R = 1k, R = 10Ω, R = 0Ω
3.0
2.0
40
nV/√Hz
pA/√Hz
pA/√Hz
n
F
G
S
+i
–i
f = 10kHz, R = 1k, R = 10Ω, R = 10k
F G S
n
f = 10kHz, R = 1k, R = 10Ω, R = 10k
n
F
G
S
R
V
IN
V
IN
= ±12V, V = ±15V
●
●
1.50
0.25
10
5
MΩ
MΩ
IN
S
= ±2V, V = ±5V
S
C
IN
Input Capacitance
V = ±15V
S
2
pF
Input Voltage Range
V = ±15V
S
●
●
±12
±2
±13.5
±3.5
V
V
S
V = ±5V
2
LT1210
ELECTRICAL CHARACTERISTICS
VCM = 0V, ±5V ≤ VS ≤ ±15V, pulse tested, VSD = 0V, unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
V = ±15V, V = ±12V
MIN
TYP
MAX
UNITS
CMRR
Common Mode Rejection Ratio
●
●
55
50
62
60
dB
dB
S
CM
V = ±5V, V = ±2V
S
CM
Inverting Input Current
Common Mode Rejection
V = ±15V, V = ±12V
V = ±5V, V = ±2V
S CM
●
●
0.1
0.1
10
10
µA/V
µA/V
S
CM
PSRR
Power Supply Rejection Ratio
V = ±5V to ±15V
●
●
60
55
77
30
dB
S
Noninverting Input Current
Power Supply Rejection
V = ±5V to ±15V
S
500
5
nA/V
Inverting Input Current
Power Supply Rejection
V = ±5V to ±15V
S
●
0.7
71
µA/V
A
V
Large-Signal Voltage Gain
T = 25°C, V = ±15V, V = ±10V,
OUT
dB
A
S
R = 10Ω (Note 3)
L
V = ±15V, V
= ±8.5V, R = 10Ω (Note 3)
●
●
55
55
68
68
dB
dB
S
OUT
L
V = ±5V, V
= ±2V, R = 10Ω
L
S
OUT
–
R
OL
Transresistance, ∆V /∆I
T = 25°C, V = ±15V, V
L
= ±10V,
OUT IN
A
S
OUT
R = 10Ω (Note 3)
100
75
260
200
kΩ
kΩ
kΩ
V = ±15V, V
= ±8.5V, R = 10Ω (Note 3)
●
●
S
OUT
L
V = ±5V, V
= ±2V, R = 10Ω
75
200
S
OUT
L
V
OUT
Maximum Output Voltage Swing
T = 25°C, V = ±15V, R = 10Ω (Note 3)
±10.0
±8.5
±11.5
V
V
A
S
L
●
T = 25°C, V = ±5V, R = 10Ω
±2.5
±2.0
±3.0
V
V
A
S
L
●
●
I
I
Maximum Output Current (Note 3)
Supply Current (Note 3)
V = ±15V, R = 1Ω
1.1
2.0
35
A
OUT
S
S
L
T = 25°C, V = ±15V, V = 0V
50
65
mA
mA
A
S
SD
●
Supply Current, R = 51k (Notes 3, 4)
T = 25°C, V = ±15V
15
30
200
10
mA
µA
µA
SD
A
S
Positive Supply Current, Shutdown
Output Leakage Current, Shutdown
V = ±15V, V = 15V
●
●
S
SD
V = ±15V, V = 15V
S
SD
SR
BW
The
Slew Rate (Note 5)
Slew Rate (Note 3)
T = 25°C, A = 2, R = 400Ω
400
900
900
V/µs
V/µs
A
V
L
T = 25°C, A = 2, R = 10Ω
A
V
L
Differential Gain (Notes 3, 6)
Differential Phase (Notes 3, 6)
Small-Signal Bandwidth
V = ±15V, R = 750Ω, R = 750Ω, R = 15Ω
0.3
0.1
55
%
DEG
MHz
S
F
G
L
V = ±15V, R = 750Ω, R = 750Ω, R = 15Ω
S
F
G
L
A = 2, V = ±15V, Peaking ≤ 1dB,
V
S
R = R = 680Ω, R = 100Ω
F
G
L
A = 2, V = ±15V, Peaking ≤ 1dB,
35
MHz
V
S
R = R = 576Ω, R = 10Ω
F
G
L
●
denotes specifications which apply for 0°C ≤ T ≤ 70°C.
supply voltages greater than ±5V, use the TO-220 or DD package. See
“Thermal Considerations” in the Applications Information section for
details on calculating junction temperature. If the maximum dissipation of
the package is exceeded, the device will go into thermal shutdown.
Note 4: R is connected between the Shutdown pin and ground.
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.
A
Note 1: 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 2: Commercial grade parts are designed to operate over the
SD
temperature range of –40°C ≤ T ≤ 85°C, but are neither tested nor
A
guaranteed beyond 0°C ≤ T ≤ 70°C. Industrial grade parts tested over
A
F
G
L
–40°C ≤ T ≤ 85°C are available on special request. Consult factory.
Note 6: NTSC composite video with an output level of 2V.
A
Note 3: SO package is recommended for ±5V supplies only, as the power
dissipation of the SO package limits performance on higher supplies. For
3
LT1210
W
U
U
SMALL-SIGNAL BANDWIDTH
RSD = 0Ω, IS = 30mA, VS = ±5V, Peaking ≤ 1dB
RSD = 0Ω, IS = 35mA, VS = ±15V, Peaking ≤ 1dB
–3dB BW
(MHz)
–3dB BW
(MHz)
A
R
L
R
F
R
A
R
L
R
F
R
G
V
G
V
–1
150
30
10
549
590
619
549
590
619
52.5
39.7
26.5
–1
150
30
10
604
649
665
604
649
665
66.2
48.4
46.5
1
150
30
10
604
649
619
–
–
–
53.5
39.7
27.4
1
150
30
10
750
866
845
–
–
–
56.8
35.4
24.7
2
150
30
10
562
590
576
562
590
576
51.8
38.8
27.4
2
150
30
10
665
715
576
665
715
576
52.5
38.9
35.0
10
150
30
10
453
432
221
49.9
47.5
24.3
61.5
43.1
45.5
10
150
30
10
392
383
215
43.2
42.2
23.7
48.4
40.3
36.0
RSD = 7.5k, IS = 15mA, VS = ±5V, Peaking ≤ 1dB
RSD = 47.5k, IS = 18mA, VS = ±15V, Peaking ≤ 1dB
–3dB BW
(MHz)
–3dB BW
(MHz)
A
R
L
R
F
R
A
R
L
R
F
R
G
V
G
V
–1
150
30
10
562
619
604
562
619
604
39.7
28.9
20.5
–1
150
30
10
619
698
698
619
698
698
47.8
32.3
22.2
1
150
30
10
634
681
649
–
–
–
41.9
29.7
20.7
1
150
30
10
732
806
768
–
–
–
51.4
33.9
22.5
2
150
30
10
576
604
576
576
604
576
40.2
29.6
21.6
2
150
30
10
634
698
681
634
698
681
48.4
33.0
22.5
10
150
30
10
324
324
210
35.7
35.7
23.2
39.5
32.3
27.7
10
150
30
10
348
357
205
38.3
39.2
22.6
46.8
36.7
31.3
RSD = 15k, IS = 7.5mA, VS = ±5V, Peaking ≤ 1dB
RSD = 82.5k, IS = 9mA, VS = ±15V, Peaking ≤ 1dB
–3dB BW
(MHz)
–3dB BW
(MHz)
A
R
L
R
F
R
A
R
L
R
F
R
G
V
G
V
–1
150
30
10
536
549
464
536
549
464
28.2
20.0
15.0
–1
150
30
10
590
649
576
590
649
576
34.8
22.5
16.3
1
150
30
10
619
634
511
–
–
–
28.6
19.8
14.9
1
150
30
10
715
768
649
–
–
–
35.5
22.5
16.1
2
150
30
10
536
549
412
536
549
412
28.3
19.9
15.7
2
150
30
10
590
665
549
590
665
549
35.3
22.5
16.8
10
150
30
10
150
118
100
16.5
13.0
11.0
31.5
27.1
19.4
10
150
30
10
182
182
100
20.0
20.0
11.0
37.2
28.9
22.5
4
LT1210
W U
TYPICAL PERFOR A CE CHARACTERISTICS
Bandwidth and Feedback Resistance
vs Capacitive Load for Peaking ≤ 1dB
Bandwidth vs Supply Voltage
Bandwidth vs Supply Voltage
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
10k
100
PEAKING ≤ 1dB
PEAKING ≤ 5dB
A
= 2
= 10Ω
A
= 2
= 100Ω
PEAKING ≤ 1dB
PEAKING ≤ 5dB
V
L
V
L
BANDWIDTH
R
R
R
= 470Ω
R
F
= 560Ω
F
R
F
= 560Ω
R
= 750Ω
F
1k
10
R
F
= 750Ω
R
= 1k
F
R
F
= 680Ω
FEEDBACK RESISTANCE
R
F
= 1k
A
= 2
R
F
= 2k
V
L
R
V
=
∞
R
F
= 1.5k
16
= ±15V
S
C
= 0.01µF
COMP
100
1
4
12
14
16
6
8
10
18
4
12
14
1
10
100
1000
10000
6
8
10
18
18
15
SUPPLY VOLTAGE (±V)
CAPACITIVE LOAD (pF)
SUPPLY VOLTAGE (±V)
1210 G03
1210 G02
1210 G01
Bandwidth and Feedback Resistance
vs Capacitive Load for Peaking ≤ 5dB
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
R
= 10
= 100Ω
A = 10
V
R = 10Ω
L
PEAKING ≤ 1dB
PEAKING ≤ 5dB
PEAKING ≤ 1dB
V
L
BANDWIDTH
R
R
= 330Ω
R
F
=390Ω
F
R
F
= 680Ω
R
F
= 560Ω
1k
10
= 470Ω
= 680Ω
FEEDBACK
RESISTANCE
F
R
F
= 1k
R
F
A
= +2
V
L
S
R
= ∞
R
F
= 1.5k
V
C
= ±15V
R
F
= 1.5k
14
= 0.01µF
COMP
100
1
10000
1
10
100
1000
16
4
12
14
16
4
12
6
8
10
18
6
8
10
CAPACITIVE LOAD (pF)
SUPPLY VOLTAGE (±V)
SUPPLY VOLTAGE (±V)
1210 G06
1210 G05
1210 G04
Differential Phase vs
Supply Voltage
Differential Gain vs
Supply Voltage
Spot Noise Voltage and Current
vs Frequency
100
10
1
0.5
0.4
0.3
0.2
0.1
0
0.6
0.5
0.4
0.3
0.2
0.1
0
R
A
= R = 750Ω
= 2
F
V
G
R
= 10Ω
L
–i
n
R
= 10Ω
L
R
V
= R = 750Ω
F
G
A
= 2
R
= 15Ω
= 50Ω
L
R
= 15Ω
L
R
L
e
n
R
= 50Ω
L
R
= 30Ω
L
R
= 30Ω
+i
n
L
5
7
9
11
13
15
10
100
1k
10k
100k
5
7
9
11
13
FREQUENCY (Hz)
SUPPLY VOLTAGE (±V)
SUPPLY VOLTAGE (±V)
1210 G09
1210 G08
1210 G07
5
LT1210
W U
TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current vs
Ambient Temperature, VS = ±5V
Supply Current vs
Ambient Temperature, VS = ±15V
Supply Current vs Supply Voltage
40
35
30
25
20
15
10
5
40
35
30
25
20
15
10
5
40
38
36
34
32
30
28
26
24
22
20
R
SD
= 0Ω
A
= 1
V
R
= ∞
L
R
= 0Ω
= 7.5k
= 15k
T = 25°C
SD
R
= 0Ω
A
SD
T = 85°C
A
R
SD
= 47.5k
= 82.5k
R
SD
T = –40°C
A
T = 125°C
A
R
SD
R
SD
A
= 1
V
R
= ∞
L
0
–50
0
0
25
50
75 100 125
–50
–25
0
25
50
75 100 125
4
12
14
16
–25
6
8
10
18
SUPPLY VOLTAGE (±V)
TEMPERATURE (°C)
TEMPERATURE (°C)
1210 G11
1210 G12
1210 G10
Supply Current vs
Shutdown Pin Current
Input Common Mode Limit vs
Junction Temperature
Output Short-Circuit Current vs
Junction Temperature
+
3.0
2.8
2.6
2.4
2.2
2.0
1.8
1.6
40
35
30
25
20
15
10
5
V
V
= ±15V
S
– 0.5
–1.0
–1.5
–2.0
2.0
SOURCING
SINKING
1.5
1.0
0.5
–
0
V
25
50
TEMPERATURE (°C)
75
100 125
–50 –25
0
0
100
200
300
400
500
–50 –25
0
100 125
25
50
75
SHUTDOWN PIN CURRENT (µA)
TEMPERATURE (°C)
1210 G15
1210 G13
1210 G14
Power Supply Rejection Ratio
vs Frequency
Output Saturation Voltage vs
Junction Temperature
Supply Current vs Large-Signal
Output Frequency (No Load)
+
V
100
90
80
70
60
50
40
30
20
70
60
50
40
30
20
10
0
A
= 2
V
S
= ±15V
R
= 2k
V
L
S
R
V
= 50Ω
L
L
S
F
–1
–2
–3
–4
R
V
=
∞
= ±15V
NEGATIVE
POSITIVE
= ±15V
R
= 10Ω
L
R
= R = 1k
G
V
= 20V
OUT
P-P
R
= 10Ω
L
4
3
2
1
R
= 2k
L
–
V
10k
100k
1M
10M
10k
100k
1M
10M
100M
–50 –25
0
100 125
25
50
75
FREQUENCY (Hz)
FREQUENCY (Hz)
TEMPERATURE (°C)
1210 G17
1210 G18
1210 G16
6
LT1210
W U
TYPICAL PERFOR A CE CHARACTERISTICS
Output Impedance in Shutdown
vs Frequency
Large-Signal Voltage Gain vs
Frequency
Output Impedance vs Frequency
100
10
10k
1k
18
15
12
9
V
O
= ±15V
S
A
= 4, R = 10Ω
L
V
F
S
I
= 0mA
R
= 680Ω, R = 220Ω
G
V
= ±15V, V = 5V
IN
P-P
R
= 82.5k
SD
R
= 0Ω
SD
1
100
10
1
6
0.1
3
0
10
0.01
100k
3
4
5
6
7
8
100k
1M
10M
100M
1M
10M
100M
10
10
10
10
10
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
1210 G20
1210 G19
1210 G21
3rd Order Intercept vs Frequency
Test Circuit for 3rd Order Intercept
56
54
52
50
48
46
44
42
40
V
= ±15V
= 10Ω
= 680Ω
= 220Ω
S
L
F
R
R
R
+
G
P
LT1210
O
–
680Ω
220Ω
MEASURE INTERCEPT AT P
10Ω
O
1210 TC01
0
4
6
8
10
2
FREQUENCY (MHz)
1210 G22
7
LT1210
PPLICATI
The LT1210 is a current feedback amplifier with high
output 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.
O U
W
U
A
S I FOR ATIO
14
12
10
8
V
S
C
L
= ±15V
= 200pF
R
= 3.4k
F
NO COMPENSATION
R
= 1.5k
F
COMPENSATION
6
4
2
0
Feedback Resistor Selection
–2
–4
–6
R
= 3.4k
F
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 less
than 1dB of peaking for various resistive loads and oper-
ating 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
upto5dB.Thesecurvesuseasolidlinewhentheresponse
has less than 1dB of peaking and a dashed line when the
response has 1dB to 5dB of peaking. The curves stop
where the response has more than 5dB of peaking.
COMPENSATION
1
10
100
FREQUENCY (MHz)
1210 F01
Figure 1
tance. Also shown is the –3dB bandwidth with the sug-
gested feedback resistor vs the load capacitance.
Although the optional compensation works well with
capacitive loads, it simply reduces the bandwidth when it
is connected with resistive loads. For instance, with a 10Ω
load, the bandwidth drops from 35MHz to 26MHz when
thecompensationisconnected. Hence, thecompensation
wasmadeoptional.Todisconnecttheoptionalcompensa-
tion, leave the COMP pin open.
For resistive loads, the COMP pin should be left open (see
Capacitive Loads section).
Capacitive Loads
Shutdown/Current Set
The LT1210 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 6dB peak at
40MHz caused by the effect of the capacitance on the
output stage. Adding a 0.01µF bypass capacitor between
theoutputandtheCOMPpinsconnectsthecompensation
and greatly reduces the peaking. A lower value feedback
resistor can now be used, resulting in a response which is
flat to ±1dB to 40MHz. The network has the greatest effect
for CL in the range of 0pF to 1000pF. The graphs of
Bandwidth and Feedback Resistance vs Capacitive Load
can be used to select the appropriate value of feedback
resistor. The values shown are for 1dB 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 capaci-
If the shutdown feature is not used, the SHUTDOWN pin
must be connected to ground or V–.
TheShutdownpincanbeusedtoeitherturnoffthebiasing
for the amplifier, reducing the quiescent current to less
than 200µA, or to control the quiescent current in normal
operation.
The total bias current in the LT1210 is controlled by the
current flowing out of the Shutdown pin. When the Shut-
down pin is open or driven to the positive supply, the part
is shut down. In the shutdown mode, the output looks like
a 70pF capacitor and the supply current is typically less
than 100µA. The Shutdown pin is referenced to the posi-
tivesupplythroughaninternalbiascircuit(seetheSimpli-
fied Schematic). An easy way to force shutdown is to use
open-drain (collector) logic. The circuit shown in Figure 2
usesa74C904buffertointerfacebetween5Vlogicandthe
LT1210. The switching time between the active and shut-
down states is about 1µs. A 24k pull-up resistor speeds
8
LT1210
O U
W
U
PPLICATI
A
S
I FOR ATIO
15V
response. The quiescent current can be reduced to 9mA in
the inverting configuration without much change in re-
sponse. In noninverting mode, however, the slew rate is
reduced as the quiescent current is reduced.
V
+
IN
V
LT1210
OUT
SD
–
R
F
–15V
5V
R
G
74C906
24k
15V
ENABLE
1210 F02
Figure 2. Shutdown Interface
up the turn-off time and ensures that the LT1210 is
completely turned off. Because the pin is referenced to
the positive supply, the logic used should have a break-
down 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.
1210 F04a
RF = 750Ω
L = 10Ω
IQ = 9mA, 18mA, 36mA
VS = ±15V
R
Figure 4a. Large-Signal Response vs IQ, AV = –1
1210 F04b
IQ = 9mA, 18mA, 36mA
S = ±15V
RF = 750Ω
L = 10Ω
V
R
AV = 1
1210 F03
RPULL-UP = 24k
IN = 1VP-P
VS = ±15V
Figure 4b. Large-Signal Response vs IQ, AV = 2
RF = 825Ω
V
R
L = 50Ω
Slew Rate
Figure 3. Shutdown Operation
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. Larger feedback resistors will reduce the
slew rate as will lower supply voltages, similar to the way
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 65
times the current in the Shutdown pin. The voltage across
the resistor in this condition is V+ – 3VBE. For example, a
82k resistor will set the quiescent supply current to 9mA
with VS = ±15V.
The photos in Figures 4a and 4b show the effect of
reducing the quiescent supply current on the large-signal
9
LT1210
PPLICATI
thebandwidthisreduced.ThephotosinFigures5a,5band
5c show the large-signal response of the LT1210 for
various gain configurations. The slew rate varies from
770V/µs for a gain of 1, to 1100V/µs for a gain of –1.
O U
W
U
A
S I FOR ATIO
When the LT1210 is used to drive capacitive loads, the
available output current can limit the overall slew rate. In
the fastest configuration, the LT1210 is capable of a slew
rateofover1V/ns. Thecurrentrequiredtoslewacapacitor
at this rate is 1mA per picofarad of capacitance, so
10,000pF would require 10A! The photo (Figure 6) shows
the large-signal behavior with CL = 10,000pF. The slew
rate is about 150V/µs, determined by the current limit of
1.5A.
1210 F05a
RF = 825Ω
L = 10Ω
VS = ±15V
R
Figure 5a. Large-Signal Response, AV = 1
1210 F06
RF = RG = 3k
RL
VS = ±15V
=
∞
Figure 6. Large-Signal Response, CL = 10,000pF
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
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.
1210 F05b
RF = RG = 750Ω
RL = 10Ω
VS = ±15V
Figure 5b. Large-Signal Response, AV = –1
Capacitance on the Inverting Input
Current feedback amplifiers require resistive feedback
from 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 invert-
ing 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.
1210 F05c
RF = RG = 750Ω
RL = 10Ω
VS = ±15V
Figure 5c. Large-Signal Response, AV = 2
10
LT1210
O U
W
U
PPLICATI
A
S I FOR ATIO
Power Supplies
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
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
resistance between the layer is small. Copper board stiff-
eners and plated through holes can also be used to spread
the heat generated by the device.
The LT1210 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
voltage changes about 500µV per volt of supply mis-
match. 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.
Power Supply Bypassing
To obtain the maximum output and the minimum distor-
tion from the LT1210, the power supply rails should be
wellbypassed. Forexample, withtheoutputstagepouring
1A current peaks into the load, a 1Ω power supply imped-
ance will cause a droop of 1V, reducing the available
outputswingbythatamount.Surfacemounttantalumand
ceramic capacitors make excellent low ESR bypass ele-
ments when placed close to the chip. For frequencies
above 100kHz, use 1µF and 100nF ceramic capacitors.
If significant power must be delivered below 100kHz,
capacitive reactance becomes the limiting factor. Larger
ceramicortantalumcapacitors, suchas4.7µF, arerecom-
mended in place of the 1µF unit mentioned above.
Tables1and2listthermalresistanceforeachpackage.For
the TO-220 package, thermal resistance is given for junc-
tion-to-case only since this package is usually mounted to
a heat sink. Measured values of thermal resistance for
severaldifferentboardsizesandcopperareasarelistedfor
each surface mount package. All measurements were
taken in still air on 3/32" FR-4 board with 2 oz copper. This
data can be used as a rough guideline in estimating
thermal resistance. The thermal resistance for each appli-
cation will be affected by thermal interactions with other
components as well as board size and shape.
Table 1. R Package, 7-Lead DD
Inadequate bypassing is evidenced by reduced output
swing and “distorted” clipping effects when the output is
driventotherails.Ifthisisobserved,checkthesupplypins
of the device for ripple directly related to the output
waveform. Significant supply modulation indicates poor
bypassing.
COPPER AREA
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
25°C/W
27°C/W
35°C/W
125 sq. mm
2500 sq. mm 2500 sq. mm
*Tab of device attached to topside copper
Thermal Considerations
Table 2. Fused 16-Lead SO Package
COPPER AREA
The LT1210 contains a thermal shutdown feature which
protects against excessive internal (junction) tempera-
ture. If the junction temperature of the device exceeds the
protection threshold, the device will begin cycling be-
tween normal operation and an off state. The cycling is not
harmful to the part. The thermal cycling occurs at a slow
rate, typically10mstoseveralseconds, whichdependson
the power dissipation and the thermal time constants of
the package and heat sinking. Raising the ambient tem-
perature until the device begins thermal shutdown gives a
good indication of how much margin there is in the
thermal design.
THERMAL RESISTANCE
TOPSIDE
BACKSIDE
BOARD AREA (JUNCTION-TO-AMBIENT)
2500 sq. mm 2500 sq. mm 5000 sq. mm
1000 sq. mm 2500 sq. mm 3500 sq. mm
40°C/W
46°C/W
48°C/W
49°C/W
56°C/W
58°C/W
59°C/W
60°C/W
61°C/W
600 sq. mm
180 sq. mm
180 sq. mm
180 sq. mm
180 sq. mm
180 sq. mm
180 sq. mm
2500 sq. mm 3100 sq. mm
2500 sq. mm 2680 sq. mm
1000 sq. mm 1180 sq. mm
600 sq. mm
300 sq. mm
100 sq. mm
0 sq. mm
780 sq. mm
480 sq. mm
280 sq. mm
180 sq. mm
11
LT1210
PPLICATI
O U
W
U
A
S I FOR ATIO
5V
T7 Package, 7-Lead TO-220
Thermal Resistance (Junction-to-Case) = 5°C/W
76mA
SD
A
Calculating Junction Temperature
The junction temperature can be calculated from the
equation:
+
2V
0V
V
O
LT1210
–2V
–
10Ω
TJ = (PD)(θJA) + TA
V
= 1.4V
RMS
O
where:
–5V
TJ = Junction Temperature
680Ω
220Ω
1210 F07
TA = Ambient Temperature
PD = Device Dissipation
Figure 7
θJA = Thermal Resistance (Junction-to-Ambient)
then:
TJ = (0.56W)(46°C/W) + 70°C = 96°C
As an example, calculate the junction temperature for the
circuit in Figure 7 for the SO and R packages assuming a
70°C ambient temperature.
for the SO package with 1000 sq. mm topside
heat sinking
The device dissipation can be found by measuring the
supplycurrents,calculatingthetotaldissipationandthen
subtracting the dissipation in the load and feedback
network.
TJ = (0.56W)(27°C/W) + 70°C = 85°C
for the R package with 1000 sq. mm topside heat
sinking
Since the maximum junction temperature is 150°C,
both packages are clearly acceptable.
PD = (76mA)(10V) – (1.4V)2/ 10 = 0.56W
U
TYPICAL APPLICATIONS
CMOS Logic to Shutdown Interface
Precision ×10 High Current Amplifier
15V
V
IN
+
LT1097
+
LT1210
COMP
SD
+
OUT
–
24k
LT1210
SD
–
0.01µF
–
500pF
3k
330Ω
5V
–15V
10k
2N3904
9.09k
1210 TA04
OUTPUT OFFSET: < 500µV
SLEW RATE: 2V/µs
1k
1210 TA03
BANDWIDTH: 4MHz
STABLE WITH C < 10nF
L
12
LT1210
U
TYPICAL APPLICATIONS
Buffer AV = 1
Distribution Amplifier
V
+
IN
V
+
IN
75Ω CABLE
75Ω
LT1210
COMP
SD
LT1210
SD
75Ω
V
OUT
–
–
*
OPTIONAL, USE WITH CAPACITIVE LOAD
0.01µF*
75Ω
R
R
F
** VALUE OF RDEPENDS ON SUPPLY
F
75Ω
75Ω
VOLTAGE AND LOADING. SELECT
FROM TYPICAL AC PERFORMANCE
TABLE OR DETERMINE EMPIRICALLY
R **
F
1210 TA06
G
1210 TA05
W
W
SI PLIFIED SCHE ATIC
+
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
1210 SS
13
LT1210
PACKAGE DESCRIPTION
U
Dimensions in inches (millimeters) unless otherwise noted.
R Package
7-Lead Plastic DD Pak
(LTC DWG # 05-08-1462)
0.060
(1.524)
TYP
0.390 – 0.415
(9.906 – 10.541)
0.060
(1.524)
0.165 – 0.180
(4.191 – 4.572)
0.256
(6.502)
0.045 – 0.055
(1.143 – 1.397)
15° TYP
+0.008
0.004
–0.004
0.060
(1.524)
0.059
(1.499)
TYP
0.183
(4.648)
0.330 – 0.370
(8.382 – 9.398)
+0.203
–0.102
0.102
(
)
0.095 – 0.115
(2.413 – 2.921)
0.075
(1.905)
0.040 – 0.060
(1.016 – 1.524)
0.026 – 0.036
(0.660 – 0.914)
0.050 ± 0.012
(1.270 ± 0.305)
0.300
(7.620)
0.013 – 0.023
(0.330 – 0.584)
+0.012
0.143
–0.020
+0.305
BOTTOM VIEW OF DD PAK
HATCHED AREA IS SOLDER PLATED
COPPER HEAT SINK
3.632
(
)
–0.508
R (DD7) 0396
S Package
16-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.386 – 0.394*
(9.804 – 10.008)
16
15
14
13
12
11
10
9
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
5
7
8
1
2
3
4
6
0.010 – 0.020
(0.254 – 0.508)
× 45°
0.053 – 0.069
(1.346 – 1.752)
0.004 – 0.010
(0.101 – 0.254)
0.008 – 0.010
(0.203 – 0.254)
0° – 8° TYP
0.050
(1.270)
TYP
0.014 – 0.019
(0.355 – 0.483)
0.016 – 0.050
0.406 – 1.270
S16 0695
*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
14
LT1210
U
Dimensions in inches (millimeters) unless otherwise noted.
PACKAGE DESCRIPTION
T7 Package
7-Lead Plastic TO-220 (Standard)
(LTC DWG # 05-08-1422)
0.165 – 0.180
(4.293 – 4.572)
0.147 – 0.155
(3.734 – 3.937)
DIA
0.390 – 0.415
(9.906 – 10.541)
0.045 – 0.055
(1.143 – 1.397)
0.230 – 0.270
(5.842 – 6.858)
0.570 – 0.620
(14.478 – 15.748)
0.620
(15.75)
TYP
0.460 – 0.500
(11.684 – 12.700)
0.330 – 0.370
(8.382 – 9.398)
0.700 – 0.728
(17.780 – 18.491)
0.095 – 0.115
(2.413 – 2.921)
0.152 – 0.202
(3.860 – 5.130)
0.260 – 0.320
(6.604 – 8.128)
0.013 – 0.023
(0.330 – 0.584)
0.040 – 0.060
(1.016 – 1.524)
0.026 – 0.036
(0.660 – 0.914)
0.135 – 0.165
(3.429 – 4.191)
0.155 – 0.195
(3.937 – 4.953)
T7 (TO-220) (FORMED) 0695
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 represen-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
15
LT1210
TYPICAL APPLICATION
U
Wideband 9W Bridge Amplifier
15V
Frequency Response
INPUT
5V
P
O
+
P-P
9W
LT1210
SD
26
23
20
17
14
11
8
T1*
R
L
10nF
–
50Ω
1
1
9W
1
1
680Ω
100nF
–15V
220Ω
5
15V
2
1
1
910Ω
–1
–4
+
LT1210
10k
100k
1M
10M
100M
SD
FREQUENCY (Hz)
10nF
–
1210 TA08
* COILTRONICS Versa-PacTM CTX-01-13033-X2
OR EQUIVALENT
–15V
1210 TA07
Versa-Pac is a trademark of Coiltronics, Inc.
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT1010
Fast ±150mA Power Buffer
20MHz Bandwidth, 75V/µs Slew Rate
LT1166
Power Output Stage Automatic Bias System
Sets Class AB Bias Currents for High Voltage/High Power
Output Stages
LT1206
Single 250mA, 60MHz Current Feedback Amplifier
Shutdown Function, Stable with CL = 10,000pF, 900V/µs
Slew Rate
LT1207
LT1227
LT1360
LT1363
Dual 250mA, 60MHz Current Feedback Amplifier
Single 140MHz Current Feedback Amplifier
Single 50MHz, 800V/µs Op Amp
Dual Version of LT1206
Shutdown Function, 1100V/µs Slew Rate
Voltage Feedback, Stable with CL = 10,000pF
Voltage Feedback, Stable with CL = 10,000pF
Single 70MHz, 1000V/µs Op Amp
LT/GP 0796 7K • PRINTED IN USA
Linear Technology Corporation
1630McCarthyBlvd.,Milpitas,CA95035-7417
16
●
●
LINEAR TECHNOLOGY CORPORATION 1996
(408) 432-1900 FAX: (408) 434-0507 TELEX: 499-3977
相关型号：
LT1210CS#TR
LT1210 - 1.1A, 35MHz Current Feedback Amplifier; Package: SO; Pins: 16; Temperature Range: 0°C to 70°C
Linear
LT1210CS#TRPBF
LT1210 - 1.1A, 35MHz Current Feedback Amplifier; Package: SO; Pins: 16; Temperature Range: 0°C to 70°C
Linear
LT1210CT7#TR
IC OP-AMP, 20000 uV OFFSET-MAX, 35 MHz BAND WIDTH, PZFM7, PLASTIC, TO-220, 7 PIN, Operational Amplifier
Linear
LT1211ACJ8
IC DUAL OP-AMP, 400 uV OFFSET-MAX, 14 MHz BAND WIDTH, CDIP8, HERMETIC SEALED, CERDIP-8, Operational Amplifier
Linear
©2020 ICPDF网 联系我们和版权申明