1
DEMO MANUAL DC194
MICROPOWER BOOST REGULATOR
LT1317/LT1317B
Micropower, 600kHz
PWM DC/DC Converters
result in small, cost effective solutions. The micropower
LT1317 shifts automatically to low power Burst Mode
TM
operation at light loads, whereas the LT1317B operates at
a fixed frequency at all loads. Both parts feature a low-
battery detector that remains active while the part is shut
down. The wide voltage ratings (12V input and 30V
switch) make the LT1317 and LT1317B versatile parts,
suitable for implementing boost, flyback and SEPIC
topologies.
Demonstration Circuit DC194 is a micropower boost
regulator that converts an input as low as 1.5V to an output
of 3.3V or 5.0V. DC194 version A uses the LT
®
1317CMS8;
version B uses the LT1317BCMS8. This circuit provides
regulated power for battery-powered devices, such as
laptop and palmtop computers, cellular phones, pagers,
LCD panels and other portable devices. It is also useful for
local conversion of logic supplies, such as 3.3V to 5V
conversion in PC card devices.
The LT1317 and LT1317B are 600kHz PWM DC/DC con-
verters. Their high operating frequency and small package
DESCRIPTIO
U
PARAMETER
CONDITIONS
VALUE
Input Voltage (Note 1)
V
OUT
= 3.3V
1.5V to 3.6V
V
OUT
= 5V
1.5V to 5.3V
Maximum Load Current, Min
V
OUT
= 3.3V, V
IN
= 1.6V
175mA
V
OUT
= 3.3V, V
IN
= 2.4V
320mA
V
OUT
= 5V, V
IN
= 2V
140mA
V
OUT
= 5V, V
IN
= 3.3V
290mA
Shutdown Current, Typ
V
IN
= 2.5V, SHDN = 0V
25
µ
A
No Load Quiescent Current, Typ
V
OUT
= 3.3V, V
IN
= 2.4V, LT1317
125
µ
A
V
OUT
= 3.3V, V
IN
= 2.4V, LT1317B
4.8mA
Note 1: This limit is based on the DC194 circuit. The LT1317 can operate
from high supply voltages.
TYPICAL PERFOR A CE CHARACTERISTICS A D BOARD PHOTO
U
U
W
DC194 BP
LOAD CURRENT (mA)
EFFICIENCY (%)
90
80
70
60
50
40
0.3
10
100
1000
DC194 G04
1
LT1317
V
OUT
= 3.3V
V
IN
= 3V
V
IN
= 1.6V
V
IN
= 2.4V
LT1317 Efficiency
Burst Mode is a trademark of Linear Technology Corportion.
, LTC and LT are registered trademarks of Linear Technology Corporation.
PERFOR A CE SU ARY
U
W
WW
Board Photo
LT1317 Efficiency
LOAD CURRENT (mA)
EFFICIENCY (%)
90
80
70
60
50
40
0.3
10
100
1000
DC194 G03
1
LT1317
V
OUT
= 5V
V
IN
= 3.3V
V
IN
= 1.6V
V
IN
= 2.4V
