LTC6103

12

6103f

will give a lowpass response. This will reduce unwanted

noise from the output, and may also be useful as a charge

reservoir to keep the output steady while driving a switch-

ing circuit such as a mux or ADC. This output capacitor

in parallel with an output resistor will create a pole in the

output response at:

f

RC

dB

OUT

OUT

–

••

•

3

1

2

=

π

Useful Equations

Voltage

SENSE

SENSE

•

G

Gain:

V

Current Gain:

I

OUT

OUT

V

R

R

SENSE

OUT

IN

=

II

R

R

V

SENSE

SENSE

IN

SEN

=

Transconductance:

S

SE

IN

SENSE

SENSE

R

I

R

R

=

=

1

Transimpedance:

OUT

IN

R

Reverse Supply Protection

Some applications may be tested with reverse-polarity

supplies due to an expectation of this type of fault during

operation. The LTC6103 is not protected internally from

external reversal of supply polarity. To prevent damage

that may occur during this condition, a Schottky diode

limit the reverse current through the LTC6103. Note that

this diode will limit the low voltage performance of the

LTC6103 by effectively reducing the supply voltage to the

In addition, if the output of the LTC6103 is wired to a

device that will effectively short it to high voltage (such as

through an ESD protection clamp) during a reverse sup-

ply condition, the LTC6103’s output should be connected

through a resistor or Schottky diode (Figure 6).

Response Time

The LTC6103 is designed to exhibit fast response to inputs

for the purpose of circuit protection or signal transmis-

sion. This response time will be affected by the external

circuit in two ways, delay and speed. If the output current

is very low and an input transient occurs, there may be an

increased delay before the output voltage begins changing.

This can be improved by increasing the minimum output

effect of increased output current is illustrated in the step

response curves in the Typical Performance Characteristics

of this data sheet. Note that the curves are labeled with

respect to the initial output currents.

APPLICATIONS INFORMATION

Figure 5. Schottky Prevents Damage During Supply Reversal

Figure 6. Additional Resistor, R3, Protects

Output During Supply Reversal

+

–

+IN

OUT

1/2

LTC6103

–IN

D1

6103 F05

LOAD

+

–

8

7

4

1

+IN

OUT

1/2

LTC6103

TO

mP

6103 F06

–IN

LOAD

ADC

R3

D1