Linear Technology LTC1515 Datasheet

FEATURES

LTC1515 Series

Step-Up/Step-Down

Switched Capacitor DC/DC

Converters with Reset

U

DESCRIPTION

■

Adjustable/Selectable 3V, 3.3V or 5V
Output Voltages

■

2V to 10V Input Voltage Range

■

Up to 50mA Output Current

■

Only Three External Capacitors Required

■

Soft Start Limits Inrush Current at Turn-On

■

Low Operating Current: 60µA

■

Very Low Shutdown Current: < 1µA

■

Shutdown Disconnects Load from V

■

V

Programmable to 3V/5V or 3.3V/5V

OUT

■

Short-Circuit and Overtemperature Protected

■

650kHz Switching Frequency

■

Open-Drain Power-On Reset Output

■

Available in SO-8 Package

Daisy-Chained Control Outputs

IN

U

APPLICATIONS

■

SIM Interface in GSM Cellular Telephones

■

Smart Card Readers

■

Local Power Supplies

■

Portable Equipment

The LTC®1515, LTC1515-3/5 and LTC1515-3.3/5 are
micropower switched capacitor DC/DC converters that
produce a regulated output voltage by either stepping up
or stepping down the input voltage. Output voltage is
adjustable using an external resistor divider (LTC1515) or
programmable to either 3V/5V (LTC1515-3/5) or 3.3V/5V
(LTC1515-3.3/5) using a logic pin.

A unique architecture allows the parts to accommodate a
wide input voltage range (2V to 10V) while maintaining
± 4% regulation. Additional circuitry prevents excessive
inrush current and output voltage ripple when large VIN to
V

differentials are present.

OUT

An internal power-on reset circuit forces the POR pin low
on initial power-up. The POR output remains low until
200ms (typ) after V

is in regulation.

OUT

The parts are short-circuit and overtemperature protected.
Battery life is maximized by very low operating currents
(ICC = 60µ A typ, ICC < 1µ A in shutdown). All three parts are
available in an SO-8 package.

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

U

TYPICAL APPLICATION

Programmable 3.3V/5V Power Supply with Power-On Reset

100k

ON OFF

RESET

5V 3.3V

1

SHDN

2

POR

LTC1515-3.3/5

3

5/3

4

GND

8

V

OUT

7

V

IN

6

+

C1

–

C1

0.22µF

5

10µF 10µF

V

OUT

I

OUT

++

= 3.3V OR 5V

= 50mA

LTC1515 • TA01

V

IN

4-CELL
NiCd

LTC1515-X 5V Output vs Input Voltage

5.2
I

= 10mA

OUT

5/3 = 3V

5.1

5.0

OUTPUT VOLTAGE (V)

4.9

4.8

2

4

3

INPUT VOLTAGE (V)

5

6

8

7

9

LT1515 • TA02

10

1

LTC1515 Series

WW

W

U

ABSOLUTE MAXIMUM RATINGS

(Note 1)

VIN to GND................................................ –0.3V to 12V

V

to GND ............................................. – 0.3V to 12V

OUT

SHDN, 5/3, FB to GND.............................. – 0.3V to 12V

V

Short-Circuit Duration............................. Indefinite

OUT

/

PACKAGE

SHDN

POR

FB

GND

T

JMAX

Consult factory for Military grade parts.

O

RDER I FOR ATIO

TOP VIEW

1

2

3

4

S8 PACKAGE

8-LEAD PLASTIC SO

= 125°C, θJA = 110°C/W

V

8

OUT

VIN

7

+

C1

6

–

C1

5

WU

ORDER PART

NUMBER

LTC1515CS8



LTC1515IS8

S8 PART MARKING

1515
1515I

U

Operating Temperature Range

Commercial .............................................0°C to 70°C

Industrial ............................................ –40°C to 85°C

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

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

ORDER PART NUMBER

LTC1515CS8-3/5
LTC1515CS8-3.3/5



LTC1515IS8-3/5
LTC1515IS8-3.3/5

S8 PART MARKING
151535

515335

515I35
15I335

1

SHDN

POR

2

5/3

3

GND

4

8-LEAD PLASTIC SO

T

= 125°C, θJA = 110°C/W

JMAX

TOP VIEW

S8 PACKAGE

V

8

OUT

VIN

7

+

C1

6

–

C1

5

ELECTRICAL CHARACTERISTICS

VIN = 2V to 10V, SHDN = 3V, C1 = 0.22µF, CIN = C

PARAMETER CONDITIONS MIN TYP MAX UNITS

Operating Voltage V

V

IN

= 3V (LTC1515-3/5) 2V ≤ VIN ≤ 8V, I

V

OUT

= 3.3V (LTC1515-3.3/5) 2V ≤ VIN ≤ 8V, I

V

OUT

= 5V (LTC1515-3/5, LTC1515-3.3/5) 2.7V ≤ VIN ≤ 10V, I

V

OUT

VFB Feedback Voltage LTC1515, VFB Ramping Negative ● 1.190 1.232 1.275 V
VFB Feedback Hysteresis LTC1515 1 %
Effective Output Resistance LTC1515, VIN = 3V, Step-Up Mode ● 30 Ω

Operating Current VIN ≤ 5V, I

V

IN

Shutdown Current SHDN = 0V, VIN ≤ 5V ● 1 µA

V

IN

Output Ripple Full Load (Note 2) 100 mV
Switching Frequency Full Load ● 500 650 800 kHz
5/3, SHDN Input Threshold V

5/3, SHDN Input Current 5/3, SHDN = V

FB Input Current FB = 1.232V ● –50 50 nA
POR Output Low Voltage I

= 10µF unless otherwise noted (Note 2).

OUT

= 5V ● 2.7 10 V

OUT

= 3V/3.3V ● 2.0 8 V

V

OUT

V

= ADJ ● 2.0 10 V

OUT

≤ 15mA ● 2.88 3.0 3.12 V

3V ≤ VIN ≤ 8V, I

3V ≤ VIN ≤ 8V, I

3.3V ≤ VIN ≤ 10V, I

VIN > 5V, I

SHDN = 0V, VIN > 5V 25 µA

IL

V

IH

5/3, SHDN = 0V ● –1 1 µA

= 100µA, VIN = 3V ● 0.05 0.4 V

SINK

OUT

≤ 50mA ● 2.88 3.0 3.12 V

OUT

≤ 15mA ● 3.17 3.3 3.43 V

OUT

≤ 50mA ● 3.17 3.3 3.43 V

OUT

≤ 15mA ● 4.8 5.0 5.2 V

OUT

≤ 50mA ● 4.8 5.0 5.2 V

OUT

= 0, SHDN = 3V ● 60 100 µA

OUT

= 0, SHDN = 3V ● 75 135 µA

OUT

● 0.4 1.0 V

● 1.0 1.6 V

IN

● –1 1 µA

P-P

2

LTC1515 Series

INPUT VOLTAGE (V)

0

OPERATING CURRENT (µA)

120

100

80

60

40

20

8

1515 G06

2

4

6

10

85°C

–40°C

25°C

V

OUT

= 5V

I

OUT

= 0mA

INPUT VOLTAGE (V)

0

OUTPUT VOLTAGE RIPPLE (mV

P-P

)

250

200

150

100

50

0

8

1515 G03

2

4

6

10

V

OUT

= 3.3V

I

OUT

= 10mA

T

A

= 25°C

C

OUT

= 10µF

C

OUT

= 22µF

C

OUT

= 47µF

ELECTRICAL CHARACTERISTICS

VIN = 2V to 10V, SHDN = 3V, C1 = 0.22µF, CIN = C

PARAMETER CONDITIONS MIN TYP MAX UNITS

POR Leakage Current V
POR Trip Point (With Respect to V
POR Trip Point Hysteresis 1%
I

Short-Circuit Current V

OUT

t

ON

POR Delay After V

The

● denotes specifications which apply over the full operating

temperature range.
Note 1: Absolute Maximum Ratings are those values beyond which the life

of the device may be impaired.

)V

OUT

= 10µF unless otherwise noted (Note 2).

OUT

= 5V ● –1 1 µA

POR

Ramping Negative ● –10 –7.5 –5 %

OUT

= 0V ● 12 40 mA

OUT

Soft Start Turn-On Time 4 ms

Above POR Threshold ● 140 200 280 ms

OUT

Note 2: For V

≥ 8V, C

IN

OUT

= 22µF.

UW

TYPICAL PERFORMANCE CHARACTERISTICS

LTC1515-X

3.3V Efficiency vs Output Current

100

V

= 3.3V

OUT

= 25°C

T

A

80

60

40

EFFICIENCY (%)

20

0

0.01 1 10

LTC1515-X 5V Output Voltage
Ripple vs Input Voltage

250

V

OUT

)

I

OUT

P-P

OUTPUT VOLTAGE RIPPLE (mV

200

150

100

= 25°C

T

A

50

0

0

VIN = 2V

VIN = 4.4V

VIN = 2.7V

VIN = 6V

0.1 100
OUTPUT CURRENT (mA)

= 5V

= 10mA

C

= 10µF

OUT

C

= 22µF

OUT

C

= 47µF

OUT

2

INPUT VOLTAGE (V)

4

6

8

1515 G01

1515 G04

LTC1515-X
5V Efficiency vs Output Current

100

80

60

40

EFFICIENCY (%)

20

V

OUT

= 25°C

T

A

0

0.01 1 10

VIN = 2.7V

= 5V

0.1 100
OUTPUT CURRENT (mA)

VIN = 6V

VIN = 3.3V

VIN = 8V

1515 G02

LTC1515-X 3.3V Output Voltage
vs Input Voltage

3.45
V

= 3.3V

OUT

= 10mA 

I

OUT

= 10µF

C

3.40

OUT

= 25°C

T

A

3.35

3.30

OUTPUT VOLTAGE (V)

3.25

10

3.20

2

0

INPUT VOLTAGE (V)

6

8

4

10

1515 G05

LTC1515-X 3.3V Output Voltage
Ripple vs Input Voltage

LTC1515-X Operating Current
vs Input Voltage

3