Linear Technology LTC1877 Demo Manual

DESCRIPTIO
Demonstration circuit DC290 is a constant-frequency
step-down converter using an LTC
monolithic synchronous regulator. The LTC1878 has an
input voltage range of 2.65V < V
has an input voltage range of 2.65V < V
LTC1878 is optimized for low voltage operation and is
ideally suited for single Li-Ion cell or 3-NiCd/NiMH cell
applications. The LTC1877, with its higher voltage capa-
bility, is ideally suited for two Li-Ion cells or 4- to 6-NiCd/
NiMH cell applications.
The exclusive use of low profile surface mount compo-
nents on this demo board results in a highly efficient
application in a small volume. The output voltage can be
selected from 1.5V, 2.5V, 3.3V or a user programmable
PERFORmANCE SU
SYMBOL PARAMETER
V Input Voltage Range
IN
V Output Voltage
OUT
TYPICAL PERFORMANCE CHARACTERISTICS AND BOARD PHOTO
EFFICIENCY CURVE
100
V = 3.6V
95 IN
90
85
80 V
IN
75
V = 5V
IN
70
65
60
55
50
0.1
1.0
OUTPUT CURRENT (mA)
®
1877 or an LTC1878
< 6V and the LTC1877
IN
< 10V. The
IN
ARY
CONDITIONS
LTC1877
LTC1878
V = 5V, SYNC/MODE = 0V, RUN = 5V, I
IN
V = 5V, SYNC/MODE = 0V, RUN = 5V, I
IN
V = 5V, SYNC/MODE = 0V, RUN = 5V, I
IN
V = 5V, SYNC/MODE = 0V, RUN = 5V, I
IN
V = 10V
IN
= 7.2V
V = 3.3V
OUT
L = 10µH
Burst Mode OPERATION
10 100 1000
290A • TA01
DEMO MANUAL DC290
NO-DESIGN SWITCHER
LTC1877/LTC1878
Monolithic Synchronous
Step-Down Regulator
voltage, by means of a jumper. The frequency is internally
set at 550kHz or can be synchronized with an external
clock. The internal switches allow up to 600mA of output
current in an MSO8 package, providing a space-efficient
solution for battery-powered applications. The DC supply
current is typically only 10µA at no load and less than 1µA
in shutdown. In switching-noise sensitive applications,
TM
Burst Mode operation can be inhibited by grounding the
SYNC/MODE pin with a jumper or synchronizing it with an
external clock. Gerber files for this circuit board are
available. Call the LTC factory.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode is a trademark of Linear Technology Corporation.
JUMPER POSITION
= 0mA JP1 = U, JP2 = L, JP3 = "1.5V"
OUT
= 0mA JP1 = U, JP2 = L, JP3 = "2.5V"
OUT
= 0mA JP1 = U, JP2 = L, JP3 = "3.3V"
OUT
= 0mA JP1 = U, JP2 = L, JP3 = "OPEN"
OUT
DEMO BOARD
VALUE
All (Note 1) 2.65V to 10V
All 2.65V to 6V
1.51V ± 0.05V
2.52V ± 0.08V
3.33V ± 0.10V
(Note 2)
1