8

LT1193

1193fb

7

6

LT1193

4

1

8

OUT

V

+

3

–

2

SHDN

5

7

6

LT1193

4

1

8

+

3

–

2

SHDN

SHDN

5

LT1193 • TA03

7

6

LT1193

4

+/REF

1

–/FB

8

+

3

–

2

5

7

6

LT1193

4

1

8

+

3

–

2

SHDN

5

(

( (

+/REF

–/FB

+/REF

–/FB

+/REF

–/FB

APPLICATIO S I FOR ATIO

In many applications and those requiring good settling

time it is important to use multiple bypass capacitors. A

0.1

µF 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

0.1

µF 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 1k

Ω,

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

No Supply Bypass Capacitors

LT1192 • TA04

LT1192 • TA05

SUPPLY BYPASS CAPACITORS = 0.1

µF

1V/DIV

0V

LT1192 • TA06

SUPPLY BYPASS CAPACITORS = 0.1

µF + 4.7µF TANTALUM

1V/DIV

0V

Settling Time Poor Bypass

Settling Time Good Bypass

0V

0V

10mV/DIV

10mV/DIV