Linear Technology LT1300 Datasheet

3.3/5V Step-Up DC/DC Converter

FEATURES

■

Up to 220mA Output Current at 5V from 2V Supply

■

Supply Voltage as Low as 1.8V

■

Up to 88% Efficiency

■

Small Inductor –10µH

■

120µA Quiescent Current

■

Shutdown to 10µA

■

Programmable 3.3V or 5V Output

■

I

Pin Programs Peak Switch Current

LIM

■

Low V

■

Uses Inexpensive Surface Mount Inductors

■

8-Lead DIP or SOIC Package

Switch: 170mV at 1A Typical

CESAT

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APPLICATIONS

■

Palmtop Computers

■

Portable Instruments

■

Bar-Code Scanners

■

DC/DC Converter Module Replacements

■

Battery Backup Supplies

■

Personal Digital Assistants

■

PCMCIA Cards

LT1300

Micropower High Efficiency

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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 program­mable 5V or 3.3V output via a logic-controlled input, no­load quiescent current of 120µ A and a shutdown pin which
reduces supply current to 10µ A. 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 sur­face mount inductors and capacitors. Operation is guaran­teed at 1.8V input. This allows more energy to be extracted
from the battery increasing operating life. The I
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 Out­put Converter see the LT1301. For increased output cur­rent see the LT1302.

Burst Mode is a trademark of Linear Technology Corporation.

LIM

pin can

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TYPICAL APPLICATIONS N

Two-Cell to 3.3V/5V Step-Up Converter 5V Output Efficiency

L1

10µH D1

5V/3.3V

2×
AA
CELL

L1 = COILCRAFT DO1608-103

OR SUMIDA CD54-100

C1 = AVX TPSD107M010R0100

OR SANYO OS-CON 16SA100M

D1 =MBRS130LT3

OR 1N5817

SELECT

+

C1
100µF

SHUTDOWN

67

V

IN

2

SELECT

LT1300

3

SHDN

PGND

81

SW

SENSE

I

LIM

GND

4



5

N/C

+

C1
100µF


5V/3.3V
OUTPUT

LT1300 TA1

90

88

86

84

82

80

EFFICIENCY (%)

78

76

74

1

VIN = 4.0V

VIN = 3.0V

VIN = 2.5V

VIN = 2.0V

10 100 500

LOAD CURRENT (mA)

LT1300 TA2

1

LT1300

WW

W

ABSOLUTE MAXIMUM RATINGS

VIN Voltage .............................................................. 10V

SW1 Voltage ............................................................ 20V

Sense Voltage .......................................................... 10V

SHUTDOWN Voltage................................................ 10V

SELECT Voltage ....................................................... 10V

I

Voltage ............................................................ 0.5V

LIM

Maximum Power Dissipation ............................. 500mW

Operating Temperature Range ..................... 0°C to 70°C

Storage Temperature Range ................. –65°C to 150°C

U

U

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PACKAGE/ORDER INFORMATION

TOP VIEW

GND

1

SEL

2

SHDN

3

SENSE

4

N8 PACKAGE

8-LEAD PLASTIC DIP



T

= 100°C, θJA = 150°C/W

JMAX

PGND

8

SW

7

V

6

IN

I

5

LIM



S8 PACKAGE

8-LEAD PLASTIC SOIC



ORDER PART

NUMBER

LT1300CN8
LT1300CS8

S8 PART MARKING

1300

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Lead Temperature (Soldering, 10 sec).................. 300°C

Consult factory for Industrial grade parts.

SEL

= 5V, V

TA = 25°C, V

SENSE

ELECTRICAL CHARACTERISTICS

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

I

Q

VINInput Voltage Range 1.8 V

V

OUT

DC Maximum Duty Cycle 75 86 95 %
t

ON

V

CESAT

V

SHDNH

V

SHDNL

V

SELH

V

SELL

I

SHDN

I

SEL

The
temperature range.

Quiescent Current V

Output Sense Voltage V

Output Referred V
Comparator Hysteresis V

Oscillator Frequency Current Limit not Asserted. See Test Circuit. 120 155 185 kHz
Oscillator TC 0.2 %/°C

Switch On Time Current Limit not Asserted. 5.6 µs
Output Line Regulation 1.8V < VIN < 6V ● 0.06 0.15 %/V
Switch Saturation Voltage ISW = 700mA ● 130 200 mV
Switch Leakage Current VSW = 5V, Switch Off ● 0.1 10 µA
Peak Switch Current I

(Internal Trip Point) I
Shutdown Pin High ● 1.8 V
Shutdown Pin Low 0.5 V
Select Pin High ● 1.5 V
Select Pin Low ● 0.8 V
Shutdown Pin Bias Current V

Select Pin Bias Current 0V < V

● denotes specifications which apply over the 0°C to 70°C

= 0.5V, V

SHDN

V

= 1.8V ● 715 µA

SHDN

= 5V ● 4.80 5.0 5.20 V

SEL

V

= 0V ● 3.15 3.3 3.45 V

SEL

= 5V (Note 1) ● 22 50 mV

SEL

= 0V (Note 1) ● 14 35 mV

SEL

Floating (See Typical Application) 0.75 1.0 1.25 A

LIM

Grounded 0.4 A

LIM

= 5V ● 920 µA

SHDN

= 2V ● 3 µA

V

SHDN

V

= 0V ● 0.1 1 µA

SHDN

< 5V ● 13 µA

SEL

= 2V unless otherwise noted.

IN

= 5.5V ● 120 200 µA

● 2.0 V

Note 1: Hysteresis specified is DC. Output ripple may be higher if
output capacitance is insufficient or capacitor ESR is excessive. See
applications section.

2

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INPUT VOLTAGE (V)

0

I

SHDN

+ I

VIN

+ I

SENSE

(µA)

40

50

60

8

LT1300 G3

30

20

0

2

4

6

10

80

70

1

3

5

7

INPUT VOLTAGE (V)

1.5

OUTPUT CURRENT (mA)

500

600

700

34

LT1300 G6

400

300

2

2.5

3.5 4.5

200

100

0

V

OUT

= 5V,

I

LIM

FLOATING

L = 22µH

COILCRAFT

DO3316-223

L = 10µH
COILCRAFT
DO1608-103

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TYPICAL PERFORMANCE CHARACTERISTICS

Efficiency

88

V

= 3.3V

OUT

86

L = 10µH

84
82

VIN = 3V

80
78
76
74

EFFICIENCY (%)

72
70
68
66

1

VIN = 2.5V

10 100 1000

LOAD CURRENT (mA)

Shutdown Pin Bias Current

20

T

= 25°C

A

18
16
14
12
10

8
6

SHUTDOWN CURRENT (µA)

4
2
0

0

13

2

SHUTDOWN VOLTAGE (V)

VIN = 2V

4

5

LT1300 G1

7

6

LT1300 G4

8

No-Load Battery Current

170
165

160
155

150
145

140
135

INPUT CURRENT (µA)

130
125
120

250
225

200
175

150

(mV)

125

CESAT

100

V

75

50
25

1.4

V

0

CESAT

0 0.1

V

= 5V

OUT

V

= 3.3V

OUT

1.81.6

2.22.0

INPUT VOLTAGE (V)

vs I

SW

0.2 0.3

0.4 0.5

SWITCH CURRENT (A)

2.62.4

0.6 0.7

3.02.8

0.8 0.9

LT1300

Total Quiescent Current
in Shutdown

3.43.2

LT1300 G2

Maximum Output Current
vs Input Voltage

1

LT1300 G5

Maximum Output Current
vs Input Voltage

900

800

700

600

500

400

300

LOAD CURRENT (mA)

200

100

0

1.5

V

= 3.3V

OUT

I

FLOATING

LIM

L = 10µH

2

2.5

INPUT VOLTAGE (V)

Transient Response
VIN = 2V, V

V

OUT

100mV/DIV

AC COUPLED

200mA

I

LOAD

0

3.5

3

LT1300 G7

OUT

200µs/DIV

= 5V

LT1300 G8

Startup Response

V

OUT

1V/DIV

V

SHDN

10V/DIV

V

= 5V

OUT

= 20Ω

R

LOAD

500µs/DIV

LT1300 G9

3