Linear Technology LT6107 Quick Start Manual

DESCRIPTION
Demonstration circuit 1363 is a General Purpose High-
Side Current-Sense Ampl if ier f eaturing the LT6107.
This demo board ampl if ies an on-board current-sense
resistor vol tage-drop, providing a precision uni-pol ar
output vol tage proportional to l oad current. The demo
circuit incl udes scal ing resistors that program the gain of
the circuit to 50V/ V. The LT6107 is pow ered f rom the
same suppl y that the sense resistor is connected to and
provides a ground ref erenced output. The LT6107 can
perf orm current measurements on suppl ies ranging f rom
2. 7V to 36V. Since the output vol tage is devel oped as a
control l ed current through a l oad resistance, ground-
l oop errors can be el iminated by simpl y l ocating the l oad
resistor at the destination point (subsequent signal
PERF ORM ANCE SU M M ARY
SYM BOL PARAM ETER
V M onitored Suppl y Input Range
IN
V M easurement Output Signal
M ON
I M easurement Output Signal (current mode)
M ON
I Output Load Current Range
OUT
I V Quiescent Current
INQ IN
t V step-response time
R M ON
OPERATING PRINCIPL ES
The LT6107 operates by ampl if ying the vol tage drop on a
sense resistor pl aced in series w ith the pow er source of a
l oad to be monitored. The sense inputs of the ampl if ier
dif f erential l y measure the sense-resistor drop to control
an internal variabl e current source that al l ow s transl ation
of the input inf ormation to a l evel ref erenced to V–
(ground in this demo circuit). The circuit gain is
establ ished by the ratio of the output resistor to the input
H ig h Te m p e ra tu re H ig h S id e
Cu rre n t S e n s e in a S OT-2 3
processing such as A/ D conversion). Remote l oading can
be eval uated by simpl y removing the on board l oad
resistor (R3).
DC1363 is f abricated f rom FR-406 high-temp epoxy-
gl ass so that the f ul l 150° operation of the LT6107 can
be demonstrated. Other key perf ormance characteristics
of the LT6107 and DC1363 are show n in the
Perf ormance Summary bel ow .
Design files for this circuit board are available. Call
the LTC factory.
L , LT are registered trademarks of Linear Technol ogy Corporation. Other product names
may be trademarks of the companies that manuf acture the products.
Specifications are at T = 25°C
A
CONDI TI ONS
I = 5A
OUT
I = 5A, R3 removed
OUT
Thermal l imit of R
SENSE
V =12V, I = 0A
IN OUT
I step f rom 0A to 5A
OUT
resistor and is essential l y as accurate as the resistors
used. In DC1363 as shipped, the sense resistor instal l ed
is 10mΩ and the resistor ratio sets the gain to 50V/ V, so
the nominal output scal ing is 500mV per Ampere of l oad
current. Other scal ings can be produced by resistor
repl acement on the demo circuit.
The DC1363 Schematic diagram is show n in Figure 2.
DEMO CIRCUIT 1 3 6 3
Q UICK S TA RT G UIDE
M I N TYP
2. 7 3... 28
2. 5
500
65
5
LT6107
L T6 1 0 7
M AX UNI TS
36 V
V
µA
5 A
µA
µs
1