9

LT1194

will appear at the (–) input if the feedback loop is properly

closed. In steady state the input signal appears at the

output of the LT1194, and 1/10 of this signal is applied

across the sense resistor. Thus the output current is

simply:

R • 10

the dominate pole for the loop, while the LT1194 is fast

enough to be transparent in the feedback path. The ratio of

the load resistor to the sense resistor should be approxi-

mately 10:1 or greater for easy compensation. For the

example shown the load resistor is 100

Ω, the sense

resistor is 5.1

Ω, and various loop compensation capaci-

tors cause the output to exhibit an underdamped, critically

and overdamped response.

FREQUENCY (Hz)

16

LT1194 • TA08

100M

10M

Voltage Gain vs Frequency

Double Terminated Cable Driver

1M

100k

14

10

12

8

6

2

4

CABLE

75

Ω

75

Ω

5V

7

6

LT1194

–5V

4

+

3

5

–

2

8

1

APPLICATIO S I FOR ATIO

LT1194 • TA09

2k

5V

–5V

5V

–5V

LT1191

LT1194

3

2

4

7

6

6

73

5

2

R

5.1

Ω

100

Ω

4

+

–

+

–

Voltage Controlled Current Source

LT1194 • TA10

±20mA CURRENT SOURCE WITH DIFFERENT

COMPENSATION CAPACITORS

Output Current Response

Differential Video Loop Thru Amplifier

for Power-Down Applications

LT1194 • TA11

–

+

1.5k

1.5k

15k

15k

CABLE

3

2

5

4

7

6

–5V

5V

LT1194

1% RESISTOR WORST-CASE CMRR = 22dB

TYPICALLY = 38dB

OUTPUT