1

LT1308A/LT1308B

FEATURES

, LTC and LT are registered trademarks of Linear Technology Corporation.

Final Electrical Specifications

High Current, Micropower

Single Cell, 600kHz

DC/DC Converters

August 1999

s

5V at 1A from a Single Li-Ion Cell

s

5V at 800mA in SEPIC Mode from Four NiCd Cells

s

Fixed Frequency Operation: 600kHz

s

Boost Converter Outputs up to 34V

s

Starts into Heavy Loads

s

Automatic Burst Mode

Light Load (LT1308A)

s

Continuous Switching at Light Loads (LT1308B)

s

s

Pin-for-Pin Upgrade Compatible with LT1308

s

Lower Quiescent Current in Shutdown: 1

µA (Max)

s

Improved Accuracy Low-Battery Detector

Reference: 200mV

±2%

s

GSM/CDMA Phones

s

Digital Cameras

s

LCD Bias Supplies

s

Answer-Back Pagers

s

GPS Receivers

s

Battery Backup Supplies

s

Handheld Computers

The LT

step-up DC/DC converters that operate over a 1V to 10V

input voltage range. They are improved versions of the

LT1308 and are recommended for use in new designs. The

LT1308A features automatic shifting to power saving

Burst Mode operation at light loads and consumes just

140

µA at no load. The LT1308B features continuous

switching at light loads and operates at a quiescent current

of 2.5mA. Both devices consume less than 1

µA in

shutdown.

Low-battery detector accuracy is significantly tighter than

the LT1308. The 200mV reference is specified at

±2% at

room and

±3% over temperature. The shutdown pin

enables the device when it is tied to a 1V or higher source

and the switch voltage rating has been increased to 36V,

enabling higher output voltage applications.

The LT1308A/LT1308B are available in the 8-lead SO and

14-lead TSSOP packages.

Burst Mode is a trademark of Linear Technology Corporation.

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.

Figure 1. LT1308B Single Li-Ion Cell to 5V/1A DC/DC Converter

SW

FB

LT1308B

L1

4.7

µH

D1

LBO

LBI

47k

R2

100k

R1*

309k

5V

1A

100pF

1308A/B F01

C1

47

µF

C2

220

µF

Li-Ion

CELL

GND

SHDN

SHUTDOWN

C1: AVX TAJC476M010

C2: AVX TPSD227M006

D1: IR 10BQ015

+

+

L1: MURATA LQH6N4R7

Converter Efficiency

LOAD CURRENT (mA)

1

95

90

85

80

75

70

65

60

55

50

10

100

1000

1308A/B F01a