LT1189

10

S

APPLICATI

I FOR ATIO

Small-Signal Transient Response

Closed-Loop Voltage Gain vs Frequency

LT1189 • AI07

LT1189 • AI08

Small-Signal Transient Response

Reducing the Closed-Loop Bandwidth

Although it is possible to reduce the closed-loop band-

width by using a feedback zero, instability can occur if the

bandwidth is made too low. An alternate technique is to do

differential filtering at the input of the amplifier. This

technique filters the differential input signal, and the

differential noise, but does not filter common-mode noise.

Common-mode noise is rejected by the LT1189’s CMRR.

10MHz Bandwidth Limited Amplifier

Using the Shutdown Feature

The LT1189 has a unique feature that allows the amplifier

to be shutdown for conserving power, or for multiplexing

several amplifiers onto a common cable. The amplifier will

dissipates 15mW while maintaining a true high impedance

output state of about 20k

Ω in parallel with the feedback

resistors. For MUX applications, the amplifiers may be

configured inverting, non-inverting, or differential. When

the output is loaded with as little as 1k

Ωfromtheamplifier’s

feedback resistors, the amplifier shuts off in 600ns. This

shutoff can be under the control of HC CMOS operating

between 0V and – 5V.

FREQUENCY (Hz)

30

LT1189 • AI06

100M

10M

1M

100k

20

10

–20

–10

0

LT1189 • AI09

5V

7

6

LT1189

–5V

4

+

REF

3

1

–

FB

2

8

909

Ω

R1

110

Ω

R2

110

Ω

C1

68pF

2

π(R1 + R2)C1

1

FILTER

CMR

SIG

100

Ω