LT1253/LT1254
1
Low Cost Dual and Quad
Video Amplifiers
The LT1253 is a low cost dual current feedback amplifier
for video applications. The LT1254 is a quad version of the
LT1253. The amplifiers are completely isolated except for
the power supply pins and therefore have excellent isola-
tion, over 94dB at 5MHz. Dual and quad amplifiers signifi-
cantly reduce costs compared with singles; the number of
insertions is reduced and fewer supply bypass capacitors
are required. In addition, these duals and quads cost less
per amplifier than single video amplifiers.
The LT1253/LT1254 amplifiers are ideal for driving low
impedance loads such as cables and filters. The wide
bandwidth and high slew rate of these amplifiers make
driving RGB signals between PCs and workstations easy.
The excellent linearity of these amplifiers makes them
ideal for composite video.
The LT1253 is available in 8-pin DIPs and the S8 surface
mount package. The LT1254 is available in 14-pin DIPs
and the S14 surface mount package. Both parts have the
industry standard dual and quad op amp pin out. For
higher performance, see the LT1229/LT1230.
■
Low Cost
■
Current Feedback Amplifiers
■
Differential Gain: 0.03%, R
L
= 150Ω, V
S
= ±5V
■
Differential Phase: 0.28°, R
L
= 150Ω, V
S
= ±5V
■
Flat to 30MHz, 0.1dB
■
90MHz Bandwidth on ±5V
■
Wide Supply Range: ±2V(4V) to ±14V(28V)
■
Low Power: 60mW per Amplifier at ±5V
S
FEATURE
D
U
ESCRIPTIO
■
RGB Cable Drivers
■
Composite Video Cable Drivers
■
Gain Blocks in IF Stages
U
S
A
O
PPLICATI
U
A
O
PPLICATITYPICAL
Transient Response
V
S
= ±5V
A
V
= 2
R
L
= 150Ω
V
O
= 1V
LT1253/54 • TA02
V
IN
V
OUT
R
G
620Ω
R
F
620Ω
75Ω
75Ω
CABLE
75Ω
+
–
1/2 LT1253
LT1253/54 • TA01
A
V
= 1 + R
F
R
G
AT AMPLIFIER OUTPUT.
6dB LESS AT V
OUT
.
BW = 90MHz
5V
–5V
2
LT1253/LT1254
A
U
G
W
A
W
U
W
ARBSOLUTEXI T
I
S
Storage Temperature Range ................ – 65°C to 150°C
Junction Temperature (Note 2)............................ 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
Total Supply Voltage (V
+
to V
–
) ............................. 28V
Input Current ..................................................... ±15mA
Output Short-Circuit Duration (Note 1)........ Continuous
Operating Temperature Range
LT1253C, LT1254C................................. 0°C to 70°C
WU
U
PACKAGE/ORDER I FOR ATIO
ORDER PART
NUMBER
ORDER PART
NUMBER
LT1254CN
LT1254CS
S8 PART MARKING
1253
LT1253CN8
LT1253CS8
N PACKAGE
14-LEAD PLASTIC DIP
+
V
D
14
13
12
11
10
9
87
6
5
4
3
2
1
OUT A
–IN A
+IN A
+IN B
–IN B
OUT B OUT C
V
–
–IN D
OUT D
TOP VIEW
A+IN D
+IN C
–IN C
C
B
S PACKAGE 
14-LEAD PLASTIC SOIC
T
JMAX
= 150°C, θ
JA
= 100°C/ W (N)
T
JMAX
= 150°C, θ
JA
= 150°C/ W (S)
8
7
6
54
3
2
1
+
–IN A
+IN A
V
TOP VIEW
N8 PACKAGE
8-LEAD PLASTIC DIP
OUT A
OUT B
–
V
–IN B
+IN B
A
B
S8 PACKAGE 
8-LEAD PLASTIC SOIC
Symbol Parameter CONDITIONS MIN TYP MAX UNITS
V
OS
Input Offset Voltage 515 mV
+I
B
Noninverting Bias Current 115 µA
–I
B
Inverting Bias Current 20 100 µA
A
VOL
Large-Signal Voltage Gain V
S
= ±5V, V
O
= ±2V, R
L
= 150Ω560 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
= 500Ω±7.0 ±10.5 V
V
S
= ±5V, R
L
= 150Ω±2.5 ±3.7 V
I
OUT
Maximum Output Current 30 55 mA
I
S
Supply Current Per Amplifier 6 11 mA
R
IN
Input Resistance 110 MΩ
C
IN
Input Capacitance 3pF
Power Supply Range Dual ±2±12 V
Single 4 24 V
Channel Separation f = 10MHz 88 dB
SR Input Slew Rate A
V
= 1 125 V/µs
Output Slew Rate A
V
= 2 250 V/µs
ELECTRICAL CHARACTERISTICS
0°C ≤ TA ≤ 70°C, VS = ±5V to ±12V, unless otherwise noted.
T
JMAX
= 150°C, θ
JA
= 70°C/ W (N)
T
JMAX
= 150°C, θ
JA
= 100°C/ W (S)
LT1253/LT1254
3
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
5.8 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:
LT1253CN8: T
J
= T
A
+ (P
D
× 100°C/W)
LT1253CS8: T
J
= T
A
+ (P
D
× 150°C/W)
LT1254CN: T
J
= T
A
+ (P
D
× 70°C/W)
LT1254CS: T
J
= T
A
+ (P
D
× 100°C/W)
TYPICAL AC PERFOR A CE
WU
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 1000 1100 None 270 51 3.4
±12 1 150 1000 None 204 48 1.3
±12 –1 1000 750 150 110 59 0.1
±12 –1 150 768 768 89 50 0.1
±12 2 1000 715 715 179 76 0.3
±12 2 150 715 715 117 62 0
±12 5 1000 680 180 106 42 0
±12 5 150 680 180 90 47 0
±12 10 1000 620 68.1 89 49 0.1
±12 10 150 620 68.1 80 46 0.1
±5 1 1000 787 None 218 53 1.5
±5 1 150 787 None 158 91 0.1
±5 –1 1000 715 715 76 28 0.1
±5 –1 150 715 715 70 30 0.1
±5 2 1000 620 620 117 58 0.1
±5 2 150 620 620 92 52 0.1
±5 5 1000 620 150 82 36 0
±5 5 150 620 150 72 34 0
±5 10 1000 562 61.9 70 35 0
±5 10 150 562 61.9 65 28 0
BANDWIDTH
DIFFERENTIAL DIFFERENTIAL
V
S
A
V
R
L
R
F
R
G
GAIN PHASE
±12 2 1000 750 750 0.01% 0.03°
±12 2 150 750 750 0.01% 0.12°
±5 2 1000 750 750 0.03% 0.18°
±5 2 150 750 750 0.03% 0.28°
NTSC VIDEO (Note 1)
ELECTRICAL CHARACTERISTICS
0°C ≤ TA ≤ 70°C, VS = ±5V to ±12V, unless otherwise noted.
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
LT1253/LT1254
CCHARA TERISTICS
UW
AT
Y
P
I
CALPER
F
O
RC
E
Supply Current vs Supply Voltage
SUPPLY VOLTAGE (±V)
SUPPLY CURRENT (mA)
12
LT1253/54 • TPC01
40816
0
10
5
1
2
3
4
6
7
8
9
2 6 10 14 18
–55°C
25°C
125°C
175°C
Output Saturation Voltage
vs Temperature
TEMPERATURE (°C)
OUTPUT SATURATION VOLTAGE (V)
V
+
–50 25 75 125
LT1253/54 • TPC02
V
–
0
1.0
–1.0
–0.5
0.5
–25 50 100
R
L
=
∞
±2V ≤ V
S
≤ ±12V
Input Common-Mode Limit
vs Temperature
TEMPERATURE (°C)
COMMON-MODE RANGE (V)
2.0
V
+
–50 25 75 125
LT1253/54 • TPC03
V
–
0
1.0
–1.0
–2.0
–0.5
–1.5
1.5
0.5
–25 50 100
V
+
= 2V TO 12V
V
–
= –2V TO –12V
SETTLING TIME (ns)
OUTPUT STEP (V)
60
LT1253/54 • TPC04
200 40 80 100
–10
10
0
–8
–6
–4
–2
2
4
6
8NONINVERTING
INVERTING
V
S
= ±12V
R
F
= R
G
= 1k
INVERTING
NONINVERTING
Settling Time to 10mV
vs Output Step 2nd and 3rd Harmonic Distortion
vs Frequency
FREQUENCY (MHz)
1
–70
DISTORTION (dBc)
–60
–50
–40
–30
–20
10 100
LT1253/54 • TPC05
VS = ±12V
VO = 2VP-P
RL = 100Ω
RF = 750Ω
AV = 10dB 2ND
3RD
Power Supply Rejection
vs Frequency
FREQUENCY (Hz)
POWER SUPPLY REJECTION (dB)
40
80
10k 1M 10M 100M
LT1253/54 • TPC06
0100k
V
S
= ±12V
R
L
= 100Ω
R
F
= R
G
= 750Ω
NEGATIVE
20
60
POSITIVE
Spot Noise Voltage and Current
vs Frequency
FREQUENCY (Hz)
10
1
10
100
1k 100k
LT1253/54 • TPC07
100 10k
SPOT NOISE (nV/√Hz OR pA/√Hz)
–i
n
e
n
+i
n
Output Impedance
vs Frequency
FREQUENCY (Hz)
OUTPUT IMPEDANCE (Ω)
0.1
100
10k 1M 10M 100M
LT1253/54 • TPC08
0.001 100k
0.01
10
V
S
= ±12V
1.0 R
F
= R
G
= 2k
R
F
= R
G
= 750Ω
Output Short-Circuit Current
vs Temperature
TEMPERATURE (°C)
–25
OUTPUT SHORT-CIRCUIT CURRENT (mA)
40
60
100 150
LT1253/54 • TPC09
0–50 25 50 75 125 175
30
70
50
LT1253/LT1254
5
CCHARA TERISTICS
UW
AT
Y
P
I
CALPER
F
O
RC
E
±12V Frequency Response ±5V Frequency Response
±12V Frequency Response ±5V Frequency Response
FREQUENCY (Hz)
1M
6
GAIN (dB)
7
8
9
10M 100M 1G
LT1253/54 • TPC12
5
4
3
2
V
S
= ±12V
A
V
= 2
R
L
= 150Ω
R
F
= 715Ω
R
G
= 715Ω
–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
LT1253/54 • TPC13
5
4
3
2
V
S
= ±5V
A
V
= 2
R
L
= 150Ω
R
F
= 620Ω
R
G
= 620Ω
–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
LT1253/54 • TPC14
19
18
17
16
V
S
= ±12V
A
V
= 10
R
L
= 150Ω
R
F
= 620Ω
R
G
= 68.1Ω
–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
LT1253/54 • TPC15
19
18
17
16
V
S
= ±5V
A
V
= 10
R
L
= 150Ω
R
F
= 562Ω
R
G
= 61.9Ω
–120
–100
–80
–60
–40
–140
–160
–180
–20
PHASE (DEG)
0
PHASE
GAIN
24
25
26
–200
±12V Frequency Response ±5V Frequency Response
FREQUENCY (Hz)
1M
–1
GAIN (dB)
0
1
2
3
10M 100M 1G
LT1253/54 • TPC11
–2
–3
–4
–5
4
V
S
= ±5V
A
V
= 1
R
L
= 150Ω
R
F
= 787Ω
–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
LT1253/54 • TPC10
–2
–3
–4
–5
4
V
S
= ±12V
A
V
= 1
R
L
= 150Ω
R
F
= 1k
–120
–100
–80
–60
–40
–140
–160
–180
–20
PHASE (DEG)
0
PHASE
GAIN
–200
5
6
LT1253/LT1254
Transient Response
LT1253/54 • TPC16
Transient Response
V
S
= ±5V
A
V
= 1
R
L
= 150Ω
LT1253/54 • TPC17
R
F
= 562Ω
R
G
= 61.9Ω
V
O
= 1.5V
V
S
= ±5V
A
V
= 10
R
L
= 150Ω
R
F
= 787Ω
V
O
= 1V
Power Dissipation
The LT1253/LT1254 amplifiers combine high speed and
large output current drive into very small packages. Be-
cause these amplifiers work over a very wide supply range,
it is possible to exceed the maximum junction temperature
under certain conditions. To insure that the LT1253/
LT1254 are used properly, we must calculate the worst
case power dissipation, define the maximum ambient
temperature, select the appropriate package and then
calculate the maximum junction temperature.
The worst case amplifier power dissipation is the total of
the quiescent current times the total power supply voltage
plus the power in the IC due to the load. The quiescent
supply current of the LT1253/LT1254 has a strong nega-
tive temperature coefficient. The supply current of each
amplifier at 150°C is less than 7mA and typically is only
4.5mA. The power in the IC due to the load is a function of
the output voltage, the supply voltage and load resistance.
The worst case occurs when the output voltage is at half
supply, if it can go that far, or its maximum value if it
cannot reach half supply.
For example, let’s calculate the worst case power dissipa-
tion in a video cable driver operating on a ±12V supply that
delivers a maximum of 2V into 150Ω.
P
DMAX
= 2 × V
S
× I
SMAX
+ (V
S
– V
OMAX
) × V
OMAX
/R
L
P
DMAX
= 2 × 12V × 7mA + (12V – 2V) × 2V/150
= 0.168 + 0.133 = 0.301 Watt per Amp
Now if that is the dual LT1253, the total power in the
package is twice that, or 0.602W. We now must calculate
how much the die temperature will rise above the ambient.
The total power dissipation times the thermal resistance of
the package gives the amount of temperature rise. For the
above example, if we use the S8 surface mount package,
the thermal resistance is 150°C/W junction to ambient in
still air.
Temperature Rise = P
DMAX
× R
θJA
= 0.602W
× 150°C/W = 90.3°C
The maximum junction temperature allowed in the plastic
package is 150°C. Therefore the maximum ambient al-
lowed is the maximum junction temperature less the
temperature rise.
Maximum Ambient = 150°C – 90.3°C = 59.7°C
Note that this is less than the maximum of 70°C that is
specified in the absolute maximum data listing. In order to
use this package at the maximum ambient we must lower
the supply voltage or reduce the output swing.
APPLICATIO S I FOR ATIO
WUU U
CCHARA TERISTICS
UW
AT
Y
P
I
CALPER
F
O
RC
E
LT1253/LT1254
7
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-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
As a guideline to help in the selection of the LT1253/
LT1254, the following table describes the maximum sup-
ply voltage that can be used with each part based on the
following assumptions:
1. The maximum ambient is 70°C.
2. The load is a double-terminated video cable, 150Ω.
3. The maximum output voltage is 2V (peak or DC).
APPLICATIO S I FOR ATIO
WUU U
MAX POWER
at MAX T
A
LT1253CN8 V
S
< ±14 (Abs Max) 0.800W
LT1253CS8 V
S
< ±10.6 0.533W
LT1254CN V
S
< ±11.4 1.143W
LT1254CS V
S
< ±7.6 0.727W
SI PLIFIED SCHE ATIC
WW
One Amplifier
LT1253/54 • SS
+IN –IN VOUT
V+
V–
N8 Package
8-Lead Plastic DIP
PACKAGE DESCRIPTIO
U
Dimensions in inches (millimeters) unless otherwise noted.
N8 0392
0.045 ± 0.015
(1.143 ± 0.381)
0.100 ± 0.010
(2.540 ± 0.254)
0.065
(1.651)
TYP
0.045 – 0.065
(1.143 – 1.651)
0.130 ± 0.005
(3.302 ± 0.127)
0.020
(0.508)
MIN
0.018 ± 0.003
(0.457 ± 0.076)
0.125
(3.175)
MIN
0.009 – 0.015
(0.229 – 0.381)
0.300 – 0.320
(7.620 – 8.128)
0.325 +0.025
–0.015
+0.635
–0.381
8.255
()
12 34
8765
0.250 ± 0.010
(6.350 ± 0.254)
0.400
(10.160)
MAX
8
LT1253/LT1254
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7487
(408) 432-1900
●
FAX
: (408) 434-0507
●
TELEX
: 499-3977
N Package
14-Lead Plastic DIP
N14 0392
0.015
(0.380)
MIN
0.125
(3.175)
MIN
0.130 ± 0.005
(3.302 ± 0.127)
0.045 – 0.065
(1.143 – 1.651)
0.065
(1.651)
TYP
0.018 ± 0.003
(0.457 ± 0.076)
0.100 ± 0.010
(2.540 ± 0.254)
0.075 ± 0.015
(1.905 ± 0.381)
0.260 ± 0.010
(6.604 ± 0.254)
0.770
(19.558)
MAX
31 24567
8910
11
1213
14
0.009 – 0.015
(0.229 – 0.381)
0.300 – 0.325
(7.620 – 8.255)
0.325 +0.025
–0.015
+0.635
–0.381
8.255
()
S8 Package
8-Lead SOIC
PACKAGE DESCRIPTIO
U
Dimensions in inches (millimeters) unless otherwise noted.
1234
0.150 – 0.157
(3.810 – 3.988)
8765
0.189 – 0.197
(4.801 – 5.004)
0.228 – 0.244
(5.791 – 6.197)
0.010 – 0.020
(0.254 – 0.508)
0.016 – 0.050
0.406 – 1.270
× 45°
0°– 8° TYP
0.008 – 0.010
(0.203 – 0.254)
SO8 0392
0.053 – 0.069
(1.346 – 1.752)
0.014 – 0.019
(0.355 – 0.483)
0.004 – 0.010
(0.101 – 0.254)
0.050
(1.270)
BSC
S Package
14-Lead SOIC
1234
0.150 – 0.157
(3.810 – 3.988)
14 13
0.337 – 0.344
(8.560 – 8.738)
0.228 – 0.244
(5.791 – 6.197)
12 11 10 9
567
8
0.010 – 0.020
(0.254 – 0.508)
0.016 – 0.050
0.406 – 1.270
× 45°
0° – 8° TYP
0.008 – 0.010
(0.203 – 0.254)
SO14 0392
0.053 – 0.069
(1.346 – 1.752)
0.014 – 0.019
(0.355 – 0.483)
0.004 – 0.010
(0.101 – 0.254)
0.050
(1.270)
TYP
LINEAR TECHNOLOGY CORPORATION 1993
LT/GP 0193 10K REV 0