LT1497
Dual 125mA, 50MHz
Current Feedback Amplifier
FEATURES
s
s
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DESCRIPTION
The LT
®
1497 dual current feedback amplifier features low
power, high output drive, excellent video characteristics
and outstanding distortion performance. From a low 7mA
maximum supply current per amplifier, the LT1497 drives
±100mA
with only 1.9V of headroom. Twisted pairs can be
driven differentially with – 70dBc distortion up to 1MHz for
±40mA
peak signals.
The LT1497 is available in a low thermal resistance 16-pin
SO package for operation with supplies up to
±15V.
For
±5V
operation the device is also available in a low thermal
resistance SO-8 package. The device has thermal and
current limit circuits that protect against fault conditions.
The LT1497 is manufactured on Linear Technology’s
complementary bipolar process. The device has charac-
teristics that bridge the performance between the LT1229
and LT1207 dual current feedback amplifiers. The LT1229
has 30mA output drive, 100MHz bandwidth and 12mA
supply current. The LT1207 has 250mA output drive,
60MHz bandwidth and 40mA supply current.
, LTC and LT are registered trademarks of Linear Technology Corporation.
s
s
s
s
s
s
s
Minimum Output Current:
±
125mA
Maximum Supply Current per Amp: 7mA, V
S
=
±
5V
Bandwidth: 50MHz, V
S
=
±
15V
Slew Rate: 900V/µs, V
S
=
±15V
Wide Supply Range: V
S
=
±2.5V
to
±15V
(Enhanced
θ
JA
16-Pin SO Package)
Enhanced
θ
JA
SO-8 Package for
±5V
Operation
0.02% Differential Gain: A
V
= 2, R
L
= 150Ω
0.015° Differential Phase: A
V
= 2, R
L
= 150Ω
±13V
Output Swing: I
L
= 100mA, V
S
=
±15V
±3.1V
Output Swing: I
L
= 100mA, V
S
=
±5V
55ns Settling Time to 0.1%, 10V Step
Thermal Shutdown Protection
APPLICATIONS
s
s
s
s
s
Twisted-Pair Drivers
Video Amplifiers
Cable Drivers
Test Equipment Amplifiers
Buffers
TYPICAL APPLICATION
HDSL2 Single Pair Line Driver
560Ω
560Ω
– 40
2nd and 3rd Harmonic Distortion of
HDSL2 Single Pair Line Driver
V
S
=
±
5V
V
IN
=
±1.25V
V
OUT
=
±
2.5V
– 50
68.1Ω
DISTORTION (dBc)
1/2 LT1497
V
IN
1:1*
560Ω
560Ω
135Ω
– 60
– 70
2ND
3RD
– 80
68.1Ω
*MIDCOM 671-7807
– 90
100k
FREQUENCY (Hz)
1419 TA01
1497 TA02
1/2 LT1497
U
U
U
+
+
–
–
1M
2M
1
LT1497
ABSOLUTE
MAXIMUM
RATINGS
Total Supply Voltage (V
+
to V
–
)
LT1497CS8.......................................................... 14V
LT1497CS............................................................ 36V
Noninverting Input Current ...................................
±2mA
Output Short-Circuit Duration (Note 1) .......... Continuous
Operating Temperature Range (Note 2) ... – 40°C to 85°C
Specified Temperature Range ...................... 0°C to 70°C
Maximum Junction Temperature (See Below) ....... 150°C
Storage Temperature Range .................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................... 300°C
PACKAGE/ORDER INFORMATION
ORDER PART
NUMBER
TOP VIEW
OUT A
1
A
+IN A 3
V
–
8 V
+
7 OUT B
B
6 –IN B
5 +IN B
LT1497CS8
–IN A 2
4
S8 PACKAGE
8-LEAD PLASTIC SO
S8 PART MARKING
1497
T
JMAX
= 150°C,
θ
JA
= 80°C/ W (NOTE 3)
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
V
CM
= 0V,
±2.5V ≤
V
S
≤ ±15V
(LT1497CS),
±2.5V ≤
V
S
≤ ±5V
(LT1497CS8), pulse tested unless otherwise noted.
SYMBOL
V
OS
PARAMETER
Input Offset Voltage
Input Offset Voltage Matching
Input Offset Voltage Drift
I
IN+
Noninverting Input Current
Noninverting Input Current Matching
I
IN–
Inverting Input Current
Inverting Input Current Matching
e
n
+ i
n
– i
n
R
IN
Input Noise Voltage Density
Noninverting Input Noise Current Density
Inverting Input Noise Current Density
Input Resistance
T
A
= 25°C
q
CONDITIONS
T
A
= 25°C
q
T
A
= 25°C
q
q
T
A
= 25°C
q
T
A
= 25°C
q
T
A
= 25°C
q
f = 1kHz, R
F
= 1k, R
G
= 10Ω, R
S
= 0Ω
f = 1kHz, R
F
= 1k, R
G
= 10Ω, R
S
= 10k
f = 1kHz, R
F
= 1k, R
G
= 10Ω, R
S
= 10k
V
IN
=
±13V,
V
S
=
±15V
V
IN
=
±3V,
V
S
=
±5V
V
IN
=
±0.5V,
V
S
=
±2.5V
q
q
q
C
IN
Input Capacitance
2
U
U
W
W W
U
W
TOP VIEW
V
–
1
NC 2
OUT A 3
–IN A 4
+IN A 5
V
–
V
–
6
A
B
16 V
–
15 NC
14 V
+
13 OUT B
12 –IN B
11 +IN B
10 NC
9
V
–
ORDER PART
NUMBER
LT1497CS
NC 7
8
S PACKAGE
16-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 40°C/ W (NOTE 3)
MIN
TYP
±3
±1
10
±1
±0.3
±7
±3
3
2
20
MAX
±10
±15
±3.5
±5.0
±3
±10
±1.0
±1.5
±20
±40
±10
±15
UNITS
mV
mV
mV
mV
µV/°C
µA
µA
µA
µA
µA
µA
µA
µA
nV/√Hz
pA/√Hz
pA/√Hz
MΩ
MΩ
MΩ
pF
1.5
1.5
1.5
10
8
8
3
LT1497
ELECTRICAL CHARACTERISTICS
V
CM
= 0V,
±2.5V ≤
V
S
≤ ±15V
(LT1497CS),
±2.5V ≤
V
S
≤ ±5V
(LT1497CS8), pulse tested unless otherwise noted.
SYMBOL
PARAMETER
Input Voltage Range
CONDITIONS
V
S
=
±15V
V
S
=
±5V
V
S
=
±2.5V
V
S
=
±15V,
V
CM
=
±13V,
T
A
= 25°C
q
q
q
q
MIN
±13
±3.0
±0.5
55
53
54
52
52
50
TYP
±14
±4.0
±1.5
62
60
56
2.0
2.5
3.0
MAX
UNITS
V
V
V
dB
dB
dB
dB
dB
dB
CMRR
Common Mode Rejection Ratio
V
S
=
±5V,
V
CM
=
±3V,
T
A
= 25°C
q
V
S
=
±2.5V,
V
CM
=
±0.5V,
T
A
= 25°C
q
Inverting Input Current
Common Mode Rejection
PSRR
Power Supply Rejection Ratio
V
S
=
±15V,
V
CM
=
±13V
V
S
=
±5V,
V
CM
=
±3V
V
S
=
±2.5V,
V
CM
=
±0.5V
V
S
=
±2V
to
±15V,
T
A
= 25°C
q
q
q
q
10
10
10
µA/V
µA/V
µA/V
dB
dB
dB
dB
66
63
66
63
76
76
5
5
0.1
0.1
50
50
2
2
V
S
=
±2V
to
±5V,
T
A
= 25°C
q
Noninverting Input Current
Power Supply Rejection
Inverting Input Current
Power Supply Rejection
A
VOL
Large-Signal Voltage Gain
V
S
=
±2V
to
±15V
V
S
=
±2V
to
±5V
V
S
=
±2V
to
±15V
V
S
=
±2V
to
±5V
V
S
=
±
15V, V
OUT
=
±10V,
R
L
= 150Ω
V
S
=
±5V,
V
OUT
=
±2.5V,
R
L
= 50Ω
V
S
=
±2.5V,
V
OUT
=
±0.5V,
R
L
= 50Ω
V
S
=
±15V,
V
OUT
=
±10V,
R
L
= 150Ω
V
S
=
±5V,
V
OUT
=
±2.5V,
R
L
= 50Ω
V
S
=
±2.5V,
V
OUT
=
±0.5V,
R
L
= 50Ω
V
S
=
±15V,
R
L
= 150Ω, T
A
= 25°C
q
q
q
q
q
q
q
q
q
q
q
nA/V
nA/V
µA/V
µA/V
dB
dB
dB
kΩ
kΩ
kΩ
V
V
V
V
V
V
V
V
V
V
V
V
mA
mA
mA
66
66
66
100
100
100
±12.80
±12.60
±12.65
±12.55
±3.20
±3.10
±2.75
±2.65
±1.25
±1.15
±1.00
±0.90
±
125
±
125
80
80
80
500
500
300
±13.15
±13.0
±3.45
±3.10
±1.45
±1.15
±
220
±
220
±
140
6.0
7.0
8.0
9.0
10.5
R
OL
Transresistance,
∆V
OUT
/∆I
IN–
V
OUT
Maximum Output Swing
V
S
=
±15V,
I
L
=
±100mA,
T
A
= 25°C
q
V
S
=
±5V,
R
L
= 50Ω, T
A
= 25°C
q
V
S
=
±5V,
I
L
=
±100mA,
T
A
= 25°C
q
V
S
=
±2.5V,
R
L
= 50Ω, T
A
= 25°C
q
V
S
=
±2.5V,
I
L
=
±50mA,
T
A
= 25°C
q
I
OUT
Maximum Output Current
R
L
= 1Ω, V
S
=
±15V
R
L
= 1Ω, V
S
=
±5V
R
L
= 1Ω, V
S
=
±2.5V
V
S
=
±2.5V
to
±5V,
T
A
= 25°C
q
q
I
S
Supply Current per Amplifier
q
mA
mA
mA
mA
dB
dB
V
S
=
±15V,
T
A
= 25°C
q
7.0
q
q
Channel Separation
V
S
=
±15V,
V
OUT
=
±10V,
R
L
= 150Ω
V
S
=
±5V,
V
OUT
=
±2.5V,
R
L
= 50Ω
100
100
120
115
3
LT1497
ELECTRICAL CHARACTERISTICS
V
CM
= 0V,
±2.5V ≤
V
S
≤ ±15V
(LT1497CS),
±2.5V ≤
V
S
≤ ±5V
(LT1497CS8), pulse tested unless otherwise noted.
SYMBOL
SR
PARAMETER
Slew Rate
CONDITIONS
V
S
=
±15V,
T
A
= 25°C (Note 4)
q
MIN
500
400
200
150
TYP
900
350
50
35
30
7.5
9.5
11
15
12
10
6.8
8.4
9.7
55
50
0.02
0.19
0.08
0.41
0.015
0.235
0.045
0.310
MAX
UNITS
V/µs
V/µs
V/µs
V/µs
MHz
MHz
MHz
ns
ns
ns
%
%
%
ns
ns
ns
ns
ns
%
%
%
%
Deg
Deg
Deg
Deg
V
S
=
±5V,
T
A
= 25°C (Note 4)
q
BW
Small-Signal Bandwidth
V
S
=
±15V,
R
F
= R
G
= 560Ω, R
L
= 100Ω
V
S
=
±5V,
R
F
= R
G
= 560Ω, R
L
= 100Ω
V
S
=
±2.5V,
R
F
= R
G
= 560Ω, R
L
= 100Ω
V
S
=
±15V,
R
F
= R
G
= 560Ω, R
L
= 100Ω
V
S
=
±5V,
R
F
= R
G
= 560Ω, R
L
= 100Ω
V
S
=
±2.5V,
R
F
= R
G
= 560Ω, R
L
= 100Ω
V
S
=
±15V,
R
F
= R
G
= 560Ω, R
L
= 100Ω
V
S
=
±5V,
R
F
= R
G
= 560Ω, R
L
= 100Ω
V
S
=
±2.5V,
R
F
= R
G
= 560Ω, R
L
= 100Ω
V
S
=
±15V,
R
F
= R
G
= 560Ω, R
L
= 100Ω
V
S
=
±5V,
R
F
= R
G
= 560Ω, R
L
= 100Ω
V
S
=
±2.5V,
R
F
= R
G
= 560Ω, R
L
= 100Ω
V
S
=
±15V,
10V Step, 0.1%, A
V
= – 1
V
S
=
±5V,
5V Step, 0.1%, A
V
= – 1
V
S
=
±15V,
R
F
= R
G
= 510Ω, R
L
= 150Ω
V
S
=
±15V,
R
F
= R
G
= 510Ω, R
L
= 50Ω
V
S
=
±5V,
R
F
= R
G
= 510Ω, R
L
= 150Ω
V
S
=
±5V,
R
F
= R
G
= 510Ω, R
L
= 50Ω
V
S
=
±15V,
R
F
= R
G
= 510Ω, R
L
= 150Ω
V
S
=
±15V,
R
F
= R
G
= 510Ω, R
L
= 50Ω
V
S
=
±5V,
R
F
= R
G
= 510Ω, R
L
= 150Ω
V
S
=
±5V,
R
F
= R
G
= 510Ω, R
L
= 50Ω
t
r
Small-Signal Rise Time
Overshoot
Propagation Delay
t
s
Settling Time
Differential Gain (Note 5)
Differential Phase (Note 5)
The
q
denotes specifications which apply over the full operating
temperature range.
Note 1:
Applies to short circuits to ground only. A short circuit between the
output and either supply may damage the part when operated on supplies
greater than
±10V
Note 2:
The LT1497 is designed, characterized and expected to operate
over the temperature range of – 40°C to 85°C, but is not tested at – 40°C
and 85°C. Guaranteed industrial grade parts are available, consult factory.
Note 3:
Thermal resistance varies depending upon the amount of PC board
metal attached to the device.
θ
JA
is specified for a 2500mm
2
test board
covered with 2oz copper on both sides.
Note 4:
Slew rate is measured between
±5V
on a
±10V
output signal while
operating on
±15V
supplies with R
F
= 453Ω, R
G
= 49.9Ω and R
L
= 150Ω.
On
±5V
supplies slew rate is measured between
±1V
on a
±3V
output
signal. The slew rate is much higher when the input is overdriven and
when the amplifier is operated inverting. See the Applications Information
section.
Note 5:
NTSC composite video with an amplifier output level of 2V peak.
4
LT1497
SMALL-SIGNAL BANDWIDTH
V
S
=
±15V,
Peaking
≤
1dB
A
V
–1
R
L
150
50
20
150
50
20
150
50
20
150
50
20
R
F
560
560
620
560
560
560
510
560
620
270
270
270
R
G
560
560
620
–
–
–
510
560
620
30
30
30
– 3dB BW (MHz)
59.2
43.1
30.0
57.0
42.7
30.3
59.1
41.7
20.7
43.4
30.9
19.0
1
2
10
TYPICAL PERFORMANCE CHARACTERISTICS
Voltage Gain and Phase
vs Frequency, Gain = 6dB
9
8
7
PHASE
GAIN
±
5V
±15V
0
45
90
– 3dB BANDWIDTH (MHz)
VOLTAGE GAIN (dB)
6
5
4
3
2
1
0
135
180
±
5V
±15V
225
270
60
50
40
30
20
10
R
F
= 470Ω
R
F
= 560Ω
R
F
= 750Ω
R
F
= 1k
– 3dB BANDWIDTH (MHz)
–1
0.1
R
L
= 100Ω
R
F
= R
G
= 560Ω
1
10
FREQUENCY (MHz)
100
1497 G01
Voltage Gain and Phase
vs Frequency, Gain = 20dB
28
26
24
VOLTAGE GAIN (dB)
PHASE
±
5V
– 3dB BANDWIDTH (MHz)
22
20
18
16
14
12
10
8
0.1
R
L
= 100Ω
R
F
= 270Ω
R
G
= 30Ω
1
10
FREQUENCY (MHz)
±
5V
±15V
GAIN
135
180
225
270
60
50
40
30
20
10
R
F
= 560Ω
– 3dB BANDWIDTH (MHz)
U W
±15V
U
U
W
V
S
=
±5V,
Peaking
≤
1dB
A
V
–1
R
L
150
50
20
150
50
20
150
50
20
150
50
20
R
F
510
560
560
510
560
560
510
560
560
270
270
270
R
G
510
560
560
–
–
–
510
560
560
30
30
30
– 3dB BW (MHz)
45.0
32.0
23.2
44.3
31.7
22.9
41.7
30.4
21.9
28.1
21.9
14.6
1
2
10
– 3dB Bandwidth
vs Supply Voltage
90
80
70
PEAKING
≤
1dB
PEAKING
≤
5dB
90
– 3dB Bandwidth
vs Supply Voltage
GAIN = 2
R
L
= 1k
80
70
60
50
40
30
20
10
0
R
F
= 560Ω
R
F
= 750Ω
R
F
= 1k
R
F
= 470Ω
PEAKING
≤
1dB
PEAKING
≤
5dB
GAIN = 2
R
L
= 100Ω
PHASE SHIFT (DEG)
PHASE SHIFT (DEG)
0
0
2
4
6
8 10 12 14
SUPPLY VOLTAGE (± V)
16
18
0
2
4
6
8 10 12 14
SUPPLY VOLTAGE (± V)
16
18
1497 G02
1497 G03
– 3dB Bandwidth
vs Supply Voltage
0
45
90
90
80
70
R
F
= 270Ω
R
F
= 430Ω
PEAKING
≤
1dB
PEAKING
≤
5dB
90
GAIN = 10
R
L
= 1k
80
70
60
50
40
– 3dB Bandwidth
vs Supply Voltage
PEAKING
≤
1dB
PEAKING
≤
5dB
GAIN = 10
R
L
= 100Ω
R
F
= 430Ω
R
F
= 560Ω
R
F
= 270Ω
R
F
= 750Ω
R
F
= 1k
30
20
10
0
R
F
= 750Ω
0
2
4
R
F
= 1k
16
18
100
1497 G04
0
0
2
4
6
8 10 12 14
SUPPLY VOLTAGE (± V)
16
18
6
8 10 12 14
SUPPLY VOLTAGE (± V)
1497 G05
1497 G06
5
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