LT1308_15 Datasheet, PDF (1/8 Pages) Linear Technology – Single Cell High Current Micropower 600kHz Boost DC/DC Converter

FEATURES
s _{5V at 1A from a Single Li-Ion Cell}
s _{3.3V at 300mA from a Single NiCd Cell}
s _{Low Quiescent Current: 100µA}
s _{Operates with VIN as Low as 1V}
s _{Fixed Frequency Operation: 600kHz}
s _{Current Mode PWM Delivers Low Output Ripple}
s _{Guaranteed Start-Up into Full Load}
s _{Low Shutdown Current: 3µA}
s _{Low-Battery Comparator}
s _{Automatic Burst Mode}^TM _{Operation at Light Load}
s _{Low VCESAT Switch: 300mV at 2A}
U
APPLICATIONS
s _{GSM Terminals}
s _{Digital Cameras}
s _{Answer-Back Pagers}
s _{Cordless Telephones}
s _{DECT Phones}
s _{GPS Receivers}
s _{Battery Backup Supplies}
Final Electrical Specifications
LT1308
Single Cell High Current
Micropower 600kHz
Boost DC/DC Converter
January 1998
DESCRIPTION
The LT^®1308 is a micropower, fixed frequency boost
DC/DC converter that operates from an input voltage as
low as 1V. Capable of delivering 5V at load current of 1A
from a single Li-Ion cell, the LT1308 also features power
saving Burst Mode operation at light loads. High efficiency
is maintained over a broad 1mA to 1A load range.
The device contains a low-battery detector with a 200mV
reference and shuts down to less than 5µA quiescent
current. No-load quiescent current is 100µA and the
internal NPN power switch handles a 2A current with a
voltage drop of just 300mV.
High frequency 600kHz switching allows the use of small,
surface mount components. The LT1308’s current mode
architecture provides fast response to load and line varia-
tions. The device is available in an 8-lead SO package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode is a trademark of Linear Technology Corporation.
TYPICAL APPLICATION
4.2V TO 3V
Li-Ion
CELL
C1
10µF
SHDN
V_IN
LBI
SW
LT1308
LBO
FB
V_C
GND
R_C
47k
C_C
22nF
L1
4.7µH
R1
D1
301k
5V
1A
+
R2
100k
C2
100µF
C1: CERAMIC
C2: AVX TPS SERIES
D1: INTERNATIONAL RECTIFIER 10BQ015
L1: COILTRONICS CTX5-1
COILCRAFT DO3316-472
1308F01
Figure 1. Single Li-Ion Cell to 5V/1A DC/DC Converter
Converter Efficiency
95
V_IN = 3.6V
90
V_IN = 4.2V
85
80
V_IN = 3V
75
70
65
1
10
100
LOAD CURRENT (mA)
1000
1308 F01a
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
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