DESCRIPTION
Demonstration circuit 1172A is a low dropout linear
regulator featuring LT
®
1965, w hich comes in 5-lead
TO-220, 5-lead DD-PAK as w ell as the thermally en-
hanced 8-lead M SOP and 8-lead 3mmX3mm DFN
packages. The DC1172A has an input voltage range
from 2.3 to 20V, and is capable of delivering up to
1.1A output current. Operating quiescent current is
500µA
, reducing to less than
1µA
in shutdow n. The
DC1172A has a very low output noise, w hich makes it
ideal for logic pow er supplies, post regulator for
sw itching supplies and low noise instruments.
The LT1965 datasheet gives a complete description of
the part, operation and application information. The data-
sheet must be read in conjunction w ith this quick start
guide for demo circuit 1172A.
Design files for this circuit board are available. Call
the LTC factory.
, LTC and LT are registered trademarks of Linear Technology Corporation. ThinSOT and
Pow erPath are trademarks of Linear Technology Corporation.
Perform ance Sum m ary ( T
A
= 25
o
C )
PARAM ETER FOR BUCK REGULATOR CONDITION VALUE
M inimum Input Voltage 2.3V
M aximum Input Voltage 20V
Output Voltage V
out
V
IN
=2.5V, I
OUT
=1.1A
V
IN
=2.5V, I
OUT
=1.1A
V
IN
=2.5V, I
OUT
=1.1A
V
IN
=3.3V, I
OUT
=1.1A
V
IN
=3.3V, I
OUT
=1.1A
1.2V
+/- 4%
1.5V
+/- 4%
1.8V
+/- 4%
2.5V
+/- 4%
3.3V
+/- 4%
M aximum Output Current 1.1A
Q U ICK STA RT PROCEDU RE
Demonstration circuit 1172A is easy to set up to evaluate
the performance of the LT1965. Refer to Figure 1 for
proper measurement equipment setup and follow the
procedure below :
1. Before proceeding to test, insert jumper JP1
into the OFF position, and use VOUT Select
jumper J1 for the desired output voltage 1.2V,
1.5V, 1.8V, 2.5V, 3.3V. If the output voltage is
different from the above values, use the USER
select option and install a resistor R5.
2. Apply input voltage across Vin to Gnd. Insert
jumper JP1 into the ON position.
Check for the
proper output voltage
.
3.
Once the proper output voltage is established,
adjust the load w ithin the operating range and
observe the output voltage regulation.
L T 1 9 6 5 E
1 .1 A L o w Dro p o u t R e g u la to r
