Datasheet
8
LT1193
1193fb
V
+
7
6
LT1193
V
–
4
1
8
OUT
V
+
3
–
2
V
IN
SHDN
5
A
V
= –
R
FB
+ R
G
R
G
A
V
= +
R
FB
+ R
G
R
G
R
FB
7
6
LT1193
4
1
8
V
OUT
+
3
–
2
V
INDIFF
SHDN SHDN
5
V
O
= (V
INDIFF
+ V
IN
)
R
FB
+ R
G
R
G
R
FB
+ R
G
R
G
R
FB
R
G
R
FB
LT1193 • TA03
7
6
LT1193
4
+/REF
1
–/FB
8
V
OUT
+
3
–
2
5
V
O
=
R
FB
7
6
LT1193
4
1
8
V
OUT
+
3
–
2
V
IN
SHDN
5
R
FB
V
IN
V
IN
(
(
V
INDIFF
–V
IN
(
(
+/REF
–/FB
+/REF
–/FB
+/REF
–/FB
R
G
R
G
V
INDIFF
R
G
R
G
V
+
V
–
V
+
V
–
V
+
V
–
APPLICATIO S I FOR ATIO
WUUU
In many applications and those requiring good settling
time it is important to use multiple bypass capacitors. A
0.1µF ceramic disc in parallel with a 4.7µF tantalum is
recommended. Two oscilloscope photos with different
bypass conditions are used to illustrate the settling time
characteristics of the amplifier. Note that although the
output waveform looks acceptable at 1V/DIV, when ampli-
fied to 10mV/DIV the settling time to 10mV is 347ns for the
0.1µF bypass; the time drops to 96ns with multiple bypass
capacitors.
Operating With Low Closed-Loop Gains
The LT1193 has been optimized for closed-loop gains of
2 or greater; the frequency response illustrates the ob-
tainable closed-loop bandwidths. For a closed-loop gain
of 2 the response peaks about 2dB. Peaking can be
minimized by keeping the feedback elements below 1kΩ,
and can be eliminated by placing a capacitor across the
feedback resistor, (feedback zero). This peaking shows
up as time domain overshoot of about 40%. With the
feedback capacitor it is eliminated.
Cable Terminations
The LT1193 video difference amplifier has been optimized
as a low cost cable driver. The ±50mA guaranteed output
current enables the LT1193 to easily deliver 7.5V
P-P
into
No Supply Bypass Capacitors
LT1192 • TA04
A
V
= 10, IN DEMO BOARD, R
L
= 1k
LT1192 • TA05
SETTLING TIME TO 10mV, A
V
= 2
SUPPLY BYPASS CAPACITORS = 0.1µF
V
OUT
1V/DIV
0V
LT1192 • TA06
SETTLING TIME TO 10mV, A
V
= 2
SUPPLY BYPASS CAPACITORS = 0.1µF + 4.7µF TANTALUM
V
OUT
1V/DIV
0V
Settling Time Poor Bypass
Settling Time Good Bypass
0V
0V
V
OUT
10mV/DIV
V
OUT
10mV/DIV