LT1252
1
Low Cost
Video Amplifier
S
FEATURE
D
U
ESCRIPTIO
s
RGB Cable Drivers
s
Composite Video Cable Drivers
s
Gain Blocks in IF Stages
U
S
A
O
PPLICATI
U
A
O
PPLICATI
TYPICAL
Transient Response
LT1252 TA02
V
IN
V
OUT
R
G
620
R
F
620
75
75
CABLE
75
+
LT1252
LT1252 TA01
A
V
= 1
+
R
F
R
G
AT AMPLIFIER OUTPUT.
6dB LESS AT V
OUT
.
BW = 100MHz
5V
5V
V
S
=
5V
A
V
= 2
R
L
= 150
V
O
= 1V
s
Low Cost
s
Current Feedback Amplifier
s
Differential Gain: 0.01%, R
L
= 150
, V
S
=
5V
s
Differential Phase: 0.09
, R
L
= 150
, V
S
=
5V
s
Flat to 30MHz, 0.1dB
s
100MHz Bandwidth on
5V
s
Wide Supply Range:
2V(4V) to
14V(28V)
s
Low Power: 85mW at
5V
The LT1252 is a low cost current feedback amplifier for
video applications. The LT1252 is ideal for driving low
impedance loads such as cables and filters. The wide
bandwidth and high slew rate of this amplifier make
driving RGB signals between PCs and workstations easy.
The linearity of the LT1252 is outstanding; it is unsur-
passed for driving composite video.
The LT1252 is available in the 8-pin DIP and the S8 surface
mount package. For higher performance and shutdown
operation, see the LT1227. For dual and quad amplifiers
with similar performance see the LT1253/LT1254.
2
LT1252
A
U
G
W
A
W
U
W
A
R
BSOLUTE
XI
TI
S
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
OS
Input Offset Voltage
5
15
mV
+I
B
Noninverting Bias Current
1
15
A
I
B
Inverting Bias Current
20
100
A
A
VOL
Large-Signal Voltage Gain
V
S
=
5V, V
O
=
2V, R
L
= 150
560
1500
V/V
PSRR
Power Supply Rejection Ratio
V
S
=
3V to
12V
60
70
dB
CMRR
Common-Mode Rejection Ratio
V
S
=
5V, V
CM
=
2V
55
65
dB
V
OUT
Maximum Output Voltage Swing
V
S
=
12V, R
L
= 500
7.0
10.5
V
V
S
=
5V, R
L
= 150
2.5
3.7
V
I
OUT
Maximum Output Current
30
55
mA
I
S
Supply Current
8.5
18
mA
R
IN
Input Resistance
1
10
M
C
IN
Input Capacitance
3
pF
Power Supply Range Dual
2
12
V
Single
4
24
V
SR
Input Slew Rate
A
V
= 1
125
V/
s
Output Slew Rate
A
V
= 2
250
V/
s
W
U
U
PACKAGE/ORDER I FOR ATIO
ORDER PART
NUMBER
ORDER PART
NUMBER
S8 PART MARKING
LT1252CS8
1252
LT1252CN8
8
7
6
5
4
3
2
1
IN
+IN
NC
TOP VIEW
N8 PACKAGE
8-LEAD PLASTIC DIP
NC
V
+
V
OUT
NC
T
JMAX
= 150
C,
JA
= 150
C/ W
T
JMAX
= 150
C,
JA
= 100
C/ W
1
2
3
4
8
7
6
5
TOP VIEW
NC
V
+
OUT
NC
NC
IN
+IN
V
S8 PACKAGE
8-LEAD PLASTIC SO
ELECTRICAL CHARACTERISTICS
0
C
T
A
70
C, V
S
=
5V to
12V, unless otherwise noted.
Total Supply Voltage (V
+
to V
) ............................. 28V
Input Current .....................................................
15mA
Output Short-Circuit Duration (Note 1) ........ Continuous
Operating Temperature Range .................... 0
C to 70
C
Storage Temperature Range ................ 65
C to 150
C
Junction Temperature (Note 2)............................ 150
C
Lead Temperature (Soldering, 10 sec)................. 300
C
LT1252
3
SMALL SIGNAL
SMALL SIGNAL
SMALL SIGNAL
V
S
A
V
R
L
R
F
R
G
3dB BW (MHz)
0.1dB BW (MHz)
PEAKING (dB)
12
1
150
2370
None
282
45
1.9
12
1
1000
1100
1100
58
17
0.1
12
1
150
909
909
73
34
0.1
12
2
1000
1210
1210
253
20
0.1
12
2
150
909
909
142
38
0.1
12
5
1000
1000
249
73
25
0.1
12
5
150
866
215
75
31
0.1
12
10
1000
909
100
67
26
0.1
12
10
150
768
84.5
69
32
0.1
5
1
1000
2210
None
260
10
2.4
5
1
150
1300
None
232
50
0.8
5
1
1000
1000
1000
50
11
0.1
5
1
150
732
732
69
34
0.1
5
2
1000
909
909
133
24
0.1
5
2
150
787
787
100
30
0.1
5
5
1000
825
205
62
21
0.1
5
5
150
698
174
66
30
0.1
5
10
1000
750
82.5
58
22
0.1
5
10
150
619
68.1
60
30
0.1
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
t
r
Small-Signal Rise Time
V
S
=
12V, A
V
= 2
3.5
ns
Rise and Fall Time
V
S
=
5V, A
V
= 2, V
OUT
= 1V
P-P
5.2
ns
t
p
Propagation Delay
V
S
=
5V, A
V
= 2
3.5
ns
Note 1: A heat sink may be required to keep the junction temperature
below absolute maximum when the output is shorted indefinitely.
Note 2: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formulas:
LT1252CN8: T
J
= T
A
+ (P
D
100
C/W)
LT1252CS8: T
J
= T
A
+ (P
D
150
C/W)
TYPICAL AC PERFOR A CE
W U
BANDWIDTH
ELECTRICAL CHARACTERISTICS
0
C
T
A
70
C, V
S
=
5V to
12V, unless otherwise noted.
DIFFERENTIAL
DIFFERENTIAL
V
S
A
V
R
L
R
F
R
G
GAIN
PHASE
12
2
1000
1000
1000
0.02%
0.02
12
2
150
1000
1000
0.03%
0.04
5
2
1000
1000
1000
0.02%
0.08
5
2
150
1000
1000
0.01%
0.09
NTSC VIDEO (Note 1)
Note 1: Differential Gain and Phase are measured using a Tektronix TSG
120 YC/NTSC signal generator and a Tektronix 1780R Video Measurement
Set. The resolution of this equipment is 0.1% and 0.1
. Ten identical
amplifier stages were cascaded giving an effective resolution of 0.01% and
0.01
.
4
LT1252
C
C
HARA TERISTICS
U
W
A
TYPICAL PERFOR
CE
Supply Current vs Supply Voltage
Input Common-Mode Limit
vs Temperature
Output Saturation Voltage
vs Temperature
Settling Time to 10mV
vs Output Step
2nd and 3rd Harmonic Distortion
vs Frequency
Power Supply Rejection
vs Frequency
Spot Noise Voltage and Current
vs Frequency
FREQUENCY (Hz)
10
1
10
100
1k
100k
LT1252 TPC07
100
10k
SPOT NOISE (nV/
Hz OR pA/
Hz)
i
n
e
n
+i
n
Output Impedance
vs Frequency
Output Short-Circuit Current
vs Junction Temperature
TEMPERATURE (C)
50
30
OUTPUT SHORT-CIRCUIT CURRENT (mA)
50
0
50
100
LT1252 TPC09
40
25
25
60
70
75
150 175
125
SUPPLY VOLTAGE (V)
0
4
SUPPLY CURRENT (mA)
5
7
8
9
14
11
4
8
10
18
LT1252 TPC01
6
12
13
10
2
6
12
14
16
55C
25C
125C
175C
TEMPERATURE (C)
50
V
COMMON-MODE RANGE (V)
0.5
1.5
2.0
V
+
1.5
0
50
75
LT1252 TPC02
1.0
1.0
0.5
2.0
25
25
100
125
V
+
= 2V TO 12V
V
= 2V TO 12V
TEMPERATURE (C)
50
1.0
V
+
25
75
LT
1252 TPC03
1.0
25
0
50
100
125
0.5
V
0.5
OUTPUT SATURATION VOLTAGE (V)
R
L
=
2V
V
S
12V
SETTLING TIME (ns)
0
OUTPUT STEP (V)
2
6
10
80
LT1252 TPC04
2
6
10
20
40
60
100
0
4
8
4
8
V
S
= 12V
R
F
= R
G
= 1k
NONINVERTING
INVERTING
FREQUENCY (MHz)
1
70
DISTORTION (dBc)
60
50
40
30
20
10
100
LT1252 TPC05
V
S
= 12V
V
O
= 2V
P-P
R
L
= 100
R
F
= 820
A
V
= 10dB
2ND
3RD
FREQUENCY (Hz)
POWER SUPPLY REJECTION (dB)
20
40
60
80
10k
1M
10M
100M
LT1252 TPC06
0
100k
V
S
= 12V
R
L
= 100
R
F
= R
G
= 1k
NEGATIVE
POSITIVE
FREQUENCY (Hz)
0.1
OUTPUT IMPEDANCE (
)
10k
1M
10M
100M
LT1252 TPC08
0.001
100k
100
10
1
0.01
V
S
= 12V
R
F
= R
G
= 2k
R
F
= R
G
= 1k
LT1252
5
C
C
HARA TERISTICS
U
W
A
TYPICAL PERFOR
CE
12V Frequency Response
5V Frequency Response
12V Frequency Response
5V Frequency Response
12V Frequency Response
5V Frequency Response
FREQUENCY (Hz)
1M
1
GAIN (dB)
0
1
2
3
10M
100M
1G
LT1252 TPC10
2
3
4
5
4
V
S
= 12V
A
V
= 1
R
L
= 150
R
F
= 2.37k
120
100
80
60
40
140
160
180
20
PHASE (DEG)
0
PHASE
GAIN
5
200
FREQUENCY (Hz)
1M
1
GAIN (dB)
0
1
2
3
10M
100M
1G
LT1252 TPC11
2
3
4
5
4
V
S
= 5V
A
V
= 1
R
L
= 150
R
F
= 1.3k
120
100
80
60
40
140
160
180
20
PHASE (DEG)
0
PHASE
GAIN
5
200
FREQUENCY (Hz)
1M
6
GAIN (dB)
7
8
9
10M
100M
1G
LT1252 TPC12
5
4
3
2
V
S
= 12V
A
V
= 2
R
L
= 150
R
F
= 909
R
G
= 909
120
100
80
60
40
140
160
180
20
PHASE (DEG)
0
PHASE
GAIN
10
11
12
200
FREQUENCY (Hz)
1M
6
GAIN (dB)
7
8
9
10M
100M
1G
LT1252 TPC13
5
4
3
2
V
S
= 5V
A
V
= 2
R
L
= 150
R
F
= 787
R
G
= 787
120
100
80
60
40
140
160
180
20
PHASE (DEG)
0
PHASE
GAIN
10
11
12
200
FREQUENCY (Hz)
1M
20
GAIN (dB)
21
22
23
10M
100M
1G
LT1252 TPC14
19
18
17
16
V
S
= 12V
A
V
= 10
R
L
= 150
R
F
= 768
R
G
= 84.5
120
100
80
60
40
140
160
180
20
PHASE (DEG)
0
PHASE
GAIN
24
25
26
200
FREQUENCY (Hz)
1M
20
GAIN (dB)
21
22
23
10M
100M
1G
LT1252 TPC15
19
18
17
16
V
S
= 5V
A
V
= 10
R
L
= 150
R
F
= 619
R
G
= 68.1
120
100
80
60
40
140
160
180
20
PHASE (DEG)
0
PHASE
GAIN
24
25
26
200
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