Linear Technology LT1301 Datasheet

FEATURES

LOAD CURRENT (mA)

10 100 300

LT1301 TA2

1

0

72

74

EFFICIENCY (%)

76

78

80

82

90

84

86

88

VIN = 5V

VIN = 3.3V

■

12V at 120mA from 5V or 3.3V Supply

■

Supply Voltage as Low as 1.8V

■

Better High Current Efficiency Than CMOS

■

Up to 89% Efficiency

■

120µA Quiescent Current

■

Shutdown to 10µA

■

Programmable 5V or 12V Output

■

Low V

■

I

Pin Programs Peak Switch Current

LIM

■

Uses Inexpensive Surface Mount Inductors

■

8-Lead DIP or SOIC Package

Switch: 170mV at 1A Typical

CESAT

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APPLICATIONS

■

Flash Memory VPP Generator

■

Palmtop Computers

■

Portable Instruments

■

Bar-Code Scanners

■

Personal Digital Assistants

■

PCMCIA Cards

LT1301

Micropower High Efficiency

5V/12V Step-Up DC/DC

Converter for Flash Memory

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DESCRIPTION

The LT1301 is a micropower step-up DC/DC converter that
utilizes Burst Mode™ operation. The device can deliver 5V
or 12V from a two-cell battery input. It features program­mable 5V or 12V 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 for soft start or to program peak switch current
with a single resistor allowing the use of even smaller
inductors in lighter load applications. The LT1301 is
available in an 8-lead SOIC package, minimizing board
space requirements. For a selectable 3.3V/5V step-up
converter, please see the LT1300. For higher output
power, see the LT1302.

Burst Mode is a trademark of Linear Technology Corporation.

LIM

pin can

3.3V

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TYPICAL APPLICATIONS N

L1

V

IN

SELECT

SHDN
PGND

33µH

LT1301

5V
OR

+

C1
47µF

SHUTDOWN

*REQUIRED FOR 5V OUTPUT

L1 = COILCRAFT DO3316-333

OR SUMIDA CD73-330KC

D1 = 1N5817 OR MOTOROLA

MBRS130LT3

C1 = AVX TPSD476M016R0100

OR SANYO OS-CON 165A47M

C2 = AVX TPSD336M020R0100

OR SANYO OS-CON 205A33M

Figure 1. 3.3V/5V to 12V Step-Up Converter

SW

SENSE

I

LIM

GND

D1

N/C

+

12V
OUTPUT

C2
33µF
20V


LT1301 F1

0.1µF*


12V

V

OUT

2V/DIV

SHUTDOWN

10V/DIV

V

= 5V, V

IN

LOAD = 100Ω

Output Voltage

1ms/DIV

= 12V

OUT

Efficiency

LT1301 TAO1

LT1300 F2

1

LT1301

WW

W

ABSOLUTE MAXIMUM RATINGS

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

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

Sense Voltage .......................................................... 20V

Shutdown Voltage ................................................... 10V

Select Voltage .......................................................... 10V

I

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

LIM

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

Operating Temperature Range

LT1301C................................................... 0°C to 70°C

LT1301I .................................................. 40°C to 85°C

U

U

W

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

LT1301CN8
LT1301CS8

LT1301IS8

S8 PART MARKING

1301

1301I

U

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

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

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

Quiescent Current V

Output Sense Voltage V

Output Referred V
Comparator Hysteresis V

Oscillator Frequency Current Limit not Asserted. 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

= 0.5V, V

SHDN

V

= 1.8V ● 715 µA

SHDN

= 5V ● 11.52 12.00 12.48 V

SEL

V

= 0V ● 4.75 5.00 5.25 V

SEL

= 5V (Note 1) ● 50 100 mV

SEL

= 0V (Note 1) ● 22 50 mV

SEL

Floating (See Typical Application) 0.75 1.0 1.25 A

LIM

Grounded 0.4 A

LIM

= 5V ● 820 µA

SHDN

V

= 2V ● 3 µA

SHDN

V

= 0V ● 0.1 1 µA

SHDN

< 5V ● 13 µA

SEL

SEL

= 5V, V

TA = 25°C, V

= 5.5V ● 120 200 µA

SENSE

= 2V unless otherwise noted.

IN

● 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 operation section.

2

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SHUTDOWN VOLTAGE (V)

0



SHUTDOWN CURRENT (µA)

0

4

6

8

20

12

14

2

4

5

LT1300 G3

2

16

18

10

13

6

7

8

T

A

= 25°C

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TYPICAL PERFORMANCE CHARACTERISTICS

Total Quiescent Current

5V Output Efficiency

90
88
86
84
82

80
78

EFFICIENCY (%)

76
74
72
70

1

VIN = 3.3V

VIN = 2.5V

10 100 1000

LOAD CURRENT (mA)

LT1301 G1

Saturation Voltage vs Switch Current No-Load Input Current

250

TA = 25°C

225

200
175

150
125
100

75

SATURATION VOLTAGE (mV)

50
25

0

0 0.1

0.2 0.3
SWITCH CURRENT (A)

0.4 0.5

0.6 0.7

0.8 0.9

LT1301 G4

1

in Shutdown

80

TA = 25°C

70

60

(µA)

50

SENSE

+ I

40

VIN

+ I

30

SHDN

I

20

10

0

1

0

500

450

400

350

300

250

INPUT CURRENT (µA)

200

150

100

2

2

V

OUT

= 5V

V

OUT

34 6

4

3

INPUT VOLTAGE (V)

= 12V

5

INPUT VOLTAGE (V)

5

6

7

LT1301 G2

LT1301 G5

8

AC COUPLED

I

7

V

OUT

100mV/DIV

120mA

LOAD

0mA

LT1301

Shutdown Pin Bias Current

Load Transient Response of
Figure 1 Circuit

VIN = 5V

200µs/DIV

LT1301 G6

Load Transient Response of
Figure 1 Circuit

V

OUT

100mV/DIV

AC COUPLED

120mA

I

LOAD

0mA

VIN = 3.3V

Select Pin Transient Response

12V

V

OUT

2V/DIV

5V

V

SELECT

200µs/DIV

LT1301 G7

10V/DIV

C

= 100µF, VIN = 5V

OUT

100Ω LOAD

5ms/DIV

LT1301 G8

Select Pin Transient Response

12V

V

OUT

2V/DIV

5V

V

SELECT

10V/DIV

5ms/DIV

C

= 100µF, VIN = 3.3V

OUT

100Ω LOAD

LT1301 G9

3

LT1301

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PIN FUNCTIONS

GND (Pin 1): Signal Ground. Tie to PGND under the
package.

Sel (Pin 2): Output Select. When tied to VIN converter
regulates at 12V. When grounded or floating converter
regulates at 5V. May be driven under logic control.

SHDN (Pin 3): Shutdown. Pull high to shut down the
LT1301. Ground for normal operation.

Sense (Pin 4): “Output” Pin. Goes to internal resistive
divider. If operating at 5V output, a 0.1µ F ceramic capaci­tor is required from Sense to Ground.

I

(Pin 5): Float for 1A switch current limit. Tie to ground

LIM

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BLOCK DIAGRAM

V

IN

+

C1

for approximately 400mA. A resistor between I

LIM

and

ground sets peak current to some intermediate value .
VIN (Pin 6): Supply Pin. Must be bypassed with a large

value electrolytic to ground. Keep bypass within 0.2" of the
device.

SW (Pin 7): Switch Pin. Connect inductor and diode here.
Keep layout short and direct to minimize radio frequency
interference.

PGND (Pin 8): Power Ground. Tie to signal ground (pin 1)
under the package. Bypass capacitor from VIN should be
tied directly to PGND within 0.2" of the device.

L1

D1

V

OUT

+

C2



1.25V

REFERENCE

4

GND

1

SENSE

500k

97.5k

69.2k

SELECT

2

A1
COMPARATOR

+

–

ENABLE

V

IN

2

OFF

OSCILLATOR

155kHZ

SHUTDOWN

3

Figure 2.

A2 CURRENT 

COMPARATOR



A3 DRIVER

BIAS

SW

7

18mV

+

R1

3Ω

R2

730Ω

–

Q1

Q2

160×

1×

Q3

8.5k
I

LIM

58

PGND

LT1301 F2

4