LT1300 Datasheet, PDF (1/8 Pages) Linear Technology – Micropower High Efficiency 3.3/5V Step-Up DC/DC Converter

LT1300
Micropower High Efficiency
3.3/5V Step-Up DC/DC Converter
FEATURES
s _{Up to 220mA Output Current at 5V from 2V Supply}
s _{Supply Voltage as Low as 1.8V}
s _{Up to 88% Efficiency}
s _{Small Inductor –10µH}
s _{120µA Quiescent Current}
s _{Shutdown to 10µA}
s _{Programmable 3.3V or 5V Output}
s _{ILIM Pin Programs Peak Switch Current}
s _{Low VCESAT Switch: 170mV at 1A Typical}
s _{Uses Inexpensive Surface Mount Inductors}
s _{8-Lead DIP or SOUIC Package}
APPLICATIONS
s _{Palmtop Computers}
s _{Portable Instruments}
s _{Bar-Code Scanners}
s _{DC/DC Converter Module Replacements}
s _{Battery Backup Supplies}
s _{Personal Digital Assistants}
s _{PCMCIA Cards}
DESCRIPTION
The LT1300 is a micropower step-up DC/DC converter that
utilizes Burst Mode™ operation. The device can deliver 5V
or 3.3V from a two-cell battery input. It features program-
mable 5V or 3.3V output via a logic-controlled input, no-
load quiescent current of 120µA and a shutdown pin which
reduces supply current to 10µA. The on-chip power switch
has a low 170mV saturation voltage at a switch current of
1A, a four-fold reduction over prior designs. A 155kHz
internal oscillator allows the use of extremely small sur-
face mount inductors and capacitors. Operation is guaran-
teed at 1.8V input. This allows more energy to be extracted
from the battery increasing operating life. The I_LIM pin can
be used to program peak switch current with a single
resistor allowing the use of less expensive and smaller
inductors and capacitors in lighter load applications. The
LT1300 is available in an 8-lead SOIC package, minimizing
board space requirements. For a 5V/12V Selectable Out-
put Converter see the LT1301. For increased output cur-
rent see the LT1302.
Burst Mode is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIONS N
Two-Cell to 3.3V/5V Step-Up Converter
2×
AA
CELL
L1
10µH
D1
6
7
V_IN
SW
5V/3.3V
+ _C1 ^SELECT
100µF
2
SELECT
LT1300
SENSE
4
3
SHUTDOWN SHDN
PGND
8
5
I_LIM N/C
GND
1
5V/3.3V
OUTPUT
+ _C1
100µF
L1 = COILCRAFT DO1608-103
OR SUMIDA CD54-100
C1 = AVX TPSD107M010R0100
OR SANYO OS-CON 16SA100M
D1 = MBRS130LT3
OR 1N5817
LT1300 TA1
5V Output Efficiency
90
88
86
84
82
80
78
76
74
1
V_IN = 4.0V
V_IN = 3.0V
V_IN = 2.5V
V_IN = 2.0V
10
100
500
LOAD CURRENT (mA)
LT1300 TA2
1