Datasheet

LT6105
11
6105fa
PIN FUNCTIONS
–IN (Pin 1/Pin 1): Negative Sense Input Terminal.
Negative sense voltage input will remain functional for
voltages up to 44V, referred to V
–
. Connect –IN to an
external gain-setting resistor R
IN1
(R
IN1
= R
IN2
) to set
the gain.
V
+
(Pin 2/Pin 2): Power Supply Voltage. This pin supplies
current to the amplifi er and can operate from 2.85V to 36V,
independent of the voltages on the –IN or +IN pins.
V
–
(Pin 3/Pin 4): Negative Power Supply Voltage or Ground
for Single Supply Operation.
V
OUT
(Pin 4/Pin 5): Voltage Output:
V
OUT
= A
V
• (V
SENSE
± V
OS
)
V
OS
is the input offset voltage. A
V
is the gain set by exter-
nal R
IN1
, R
IN2
, R
OUT
. A
V
= R
OUT
/R
IN1
, for R
IN1
= R
IN2
.
NC (Pin 5/Pins 3, 6, 7): Not Connected Internally.
+IN (Pin 6/Pin 8): Positive Sense Input Terminal.
Connecting a source to V
S
+
and a load to V
S
–
will allow the
LT6105 to monitor the current through R
SENSE
, refer to
Figure 1. Connect +IN to an external gain-setting resistor
R
IN2
to set the gain. +IN remains functional for voltages
up to 44V, referred to V
–
.
Exposed Pad (Pin 7) DFN Only: V
–
. The Exposed Pad is
connected to the V
–
pin. It should be connected to the
V
–
trace of the PCB, or left fl oating.
(DCB/MS8)
BLOCK DIAGRAM
R
OUT
V
SENSE
R
SENSE
R
IN2
R
IN1
V
S
+V
S
–
LT6105
TO LOAD
SOURCE
0V TO 44V
V
OUT
= V
SENSE
•
R
OUT
R
IN2
V
OUT
= V
SENSE
•
WHERE R
IN
= R
IN1
= R
IN2
R
OUT
R
IN
A
V
=
R
OUT
R
IN
V
OUT
V
+
–IN +IN
V
–
SET R
IN1
= R
IN2
FOR BEST ACCURACY
IF R
IN1
≠ R
IN2
, THEN
R
IN1
, R
IN2
, R
OUT
ARE EXTERNAL RESISTORS
V
(–IN)
> 1.6V:
V
OUT
= V
SENSE
•
R
OUT
R
IN1
V
(–IN)
< 1.6V:
6105 F01
–
+
–
+
A1
Q2 Q3
Q1
A2
Figure 1. Simplifi ed Block Diagram