LT1190CN8#PBF Linear Technology, LT1190CN8#PBF Datasheet - Page 9

• Manufacturer Part Number: LT1190CN8#PBF
• Description: IC OP-AMP VIDEO HI-SPD SNGL 8DIP
• Manufacturer: Linear Technology

Specifications of LT1190CN8#PBF

• Applications: General Purpose
• Number Of Circuits: 1
• Slew Rate: 450 V/µs
• Current - Supply: 32mA
• Current - Output / Channel: 50mA
• Voltage - Supply, Single/dual (±): 4.75 V ~ 16 V, ±2.38 V ~ 8 V
• Mounting Type: Through Hole
• Package / Case: 8-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

APPLICATIO S I FOR ATIO
Cable Terminations
The LT1190 operational amplifier has been optimized as a
low cost video cable driver. The 50mA guaranteed output
current enables the LT1190 to easily deliver 7.5V
100 , while operating on 5V supplies or 2.6V
single 5V supply.
When driving a cable it is important to terminate the cable
to avoid unwanted reflections. This can be done in one of
two ways: single termination or double termination. With
single termination, the cable must be terminated at the
receiving end (75 to ground) to absorb unwanted en-
ergy. The best performance can be obtained by double
termination (75 in series with the output of the amplifier,
and 75 to ground at the other end of the cable). This
termination is preferred because reflected energy is ab-
sorbed at each end of the cable. When using the double
termination technique it is important to note that the signal
is attenuated by a factor of 2, or 6dB. This can be compen-
sated for by taking a gain of 2, or 6dB in the amplifier. The
cable driver has a – 3dB bandwidth in excess of 30MHz
while driving the 150 load.
Cable Driver Voltage Gain vs Frequency
–10
–2
–4
–6
–8
10
Double Terminated Cable Driver
8
6
4
2
0
100k
R
G
3
2
U
+
LT1190
–
R
–5V
R
R
A
5V
R
FB
G
G
A
V
1M
FB
4
7
= 330
V
= 1k
FREQUENCY (Hz)
= 1
= 1k
U
= 2
= 1k
6
R
FB
75
10M
W
CABLE
V
T
75
S
A
LT1190 • TA08
= 25 C
= 5V
100M
U
P-P
P-P
on a
into
V
Using the Shutdown Feature
The LT1190 has a unique feature that allows the amplifier
to be shut down for conserving power or for multiplexing
several amplifiers onto a common cable. The amplifier will
shut down by taking Pin 5 to V
amplifier dissipates 15mW while maintaining a true high
impedance output state of 15k
feedback resistors. The amplifiers must be used in a
noninverting configuration for MUX applications. In in-
verting configurations the input signal is fed to the output
through the feedback components. The following scope
photos show that with very high R
impedance; the output slowly decays toward ground.
Additionally, when the output is loaded with as little as 1k
the amplifier shuts off in 400ns. This shutoff can be under
the control of HC CMOS operating between 0V and – 5V.
V
SHDN
SHDN
V
V
– 5V
– 5V
OUT
OUT
0V
0V
SHUTDOWN PIN, A
1MHz SINE WAVE GATED OFF WITH
1MHz SINE WAVE GATED OFF WITH
SHUTDOWN PIN, A
Output Shutdown
Output Shutdown
V
= 1, R
V
= 1, R
L
= SCOPE PROBE
L
, the output is truly high
L
= 1k
–
in parallel with the
. In shutdown, the
LT1190 • TA10
LT1190 • TA09
LT1190
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