Linear Technology LTC1502-3.3 Datasheet

FEATURES

■

Input Voltage Range: 0.9V to 1.8V

■

0.9V Guaranteed Start-Up Voltage

■

Regulated Output Voltage: 3.3V ±4%

■

Output Current: 10mA (VIN ≥ 1V)

■

No Inductors

■

Shutdown Disconnects Load from V

■

Low Operating Current: 40µA

■

Low Shutdown Current: 5µA

■

Short-Circuit and Overtemperature Protected

■

Application Circuit Fits in <0.125in2 PCB Area

■

Available in 8-Pin MSOP and SO Packages

IN

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APPLICATIO S

■

Pagers

■

Battery Backup Supplies

■

Portable Electronic Equipment

■

Handheld Medical Instruments

■

Glucose Meters

LTC1502-3.3

Single Cell to 3.3V

Regulated Charge Pump

DC/DC Converter

U

DESCRIPTIO

The LTC®1502-3.3 is a quadrupler charge pump DC/DC
converter that produces a regulated 3.3V output from a
single alkaline cell input. It requires only five small external
capacitors—no inductors are required. Low supply cur­rent (40µA typical, 5µA in shutdown) and minimal external
components make the LTC1502-3.3 ideal for space and
power conscious single-cell applications. The total printed
circuit board area of the circuit shown below is less than

0.125in2.
Forcing the C1–/SHDN pin low through an external resis-

tive pull-down puts the part into shutdown mode. During
shutdown, the internal oscillator is stopped and the load is
disconnected from VIN. An internal pull-up current on the
C1–/SHDN pin forces the part back into normal operation
once the pull-down resistance is removed.

The LTC1502-3.3 is short-circuit protected and survives
an indefinite V
available in 8-pin MSOP and SO packages.

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

short to ground. The LTC1502-3.3 is

OUT

TYPICAL APPLICATIO

Single Cell to 3.3V DC/DC Converter

10µF

1

C2

2

C1

1µF

3

C1–/SHDN

4

GND

PCB LAYOUT FITS IN <0.125IN

V

+

LTC1502-3.3

OUT

C3

C3

+

–

V

IN

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Output Voltage vs Input Voltage

3.5

8
7

1µF

6

5

10µF

2

V

OUT

I

OUT

10µF

V

IN

SINGLE CELL
NiCd or
ALKALINE

= 3.3V

= 10mA

1502-3.3 TA01

TA = 25°C

3.4

3.3

3.2

OUTPUT VOLTAGE (V)

3.1

3.0

0.8

1.0

I

= 10mA

OUT

= 15mA

I

OUT

1.4

1.2

INPUT VOLTAGE (V)

1.6

1502-3.3 TA02

1.8

1

LTC1502-3.3

1

2

3

4

8

7

6

5

TOP VIEW

V

OUT

C3

+

C3

–

V

IN

C2

C1

+

C1–/SHDN

GND

S8 PACKAGE

8-LEAD PLASTIC SO

WW

W

ABSOLUTE MAXIMUM RATINGS

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(Note 1)

VIN to GND.................................................. –0.3V to 2V

V

to GND ............................................... – 0.3V to 5V

OUT

All Other Pins to GND ................................. –0.3V to 5V

V

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

OUT

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

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W

PACKAGE/ORDER INFORMATION

ORDER PART

TOP VIEW

C2

+

C1

C1–/SHDN

GND

8-LEAD PLASTIC MSOP

T

JMAX

1
2
3
4

MS8 PACKAGE

= 125°C, θJA = 250°C/ W

8

V

OUT

+

7

C3

–

6

C3

5

V

IN

Consult factory for Military grade parts.

NUMBER

LTC1502CMS8-3.3

MS8 PART MARKING

LTEC

Operating Temperature Range

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

Extended Commercial (Note 4).......... –40°C to 85°C

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

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

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ORDER PART

NUMBER

LTC1502CS8-3.3
LTC1502IS8-3.3

S8 PART MARKING

150233

T

= 125°C, θJA = 150°C/ W

JMAX

502I33

ELECTRICAL CHARACTERISTICS

The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.
VIN = 0.9V to 1.8V, C1 = C3 = 1µF, CIN = C2 = C

PARAMETER CONDITIONS MIN TYP MAX UNITS

VIN Operating Voltage ● 0.9 1.8 V
Minimum VIN Start-Up Voltage TA = 0°C to 70°C (Note 2) ● 0.75 0.9 V

V

Voltage I

OUT

VIN Operating Current I
VIN Shutdown Current C1–/SHDN = 0V ● 515 µA
Output Ripple I
Efficiency VIN = 1V, I
Switching Frequency Oscillator Free-Running 500 kHz
C1–/SHDN Shutdown Input Threshold C1–/SHDN in Hi-Z Sampling State ● 0.20 0.55 0.85 V
C1–/SHDN Shutdown Input Current C1–/SHDN = 0V (Note 3) ● –0.5 –2.5 – 8 µA
V

Turn-On Time VIN = 1V, I

OUT

V

Short-Circuit Current VIN = 1.5V, V

OUT

Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.

Note 2: Start-up testing is done with a 100kΩ equivalent load on V
Note 3: Currents flowing into the device are positive polarity. Currents

flowing out of the device are negative polarity.

2

= 10µF unless otherwise specified.

OUT

T

= –40°C to 85°C (Note 2) ● 1.1 V

A

≤ 3.5mA, 0.9V ≤ VIN ≤ 1.8V ● 3.17 3.3 3.43 V

OUT

≤ 10mA, 1V ≤ VIN ≤ 1.8V ● 3.17 3.3 3.43 V

I

OUT

= 0mA ● 40 90 µA

OUT

= 10mA, VIN = 1.25V 50 mV

OUT

= 10mA 77 %

OUT

= 0mA 5 ms

OUT

Forced to 0V 20 mA

OUT

Note 4: Commercial grade specifications are guaranteed over the 0°C to
70°C operating temperature range. In addition, commercial grade

OUT

.

specifications are assured over the –40°C to 85°C operating temperature
range by design, characterization and correlation with statistical process
controls. Industrial grade specifications are guaranteed and tested over the
–40°C to 85°C operating temperature range.

P-P

UW

TYPICAL PERFOR A CE CHARACTERISTICS

LTC1502-3.3

No Load Input Current
vs Input Voltage

80

I

= 0mA

OUT

60

40

INPUT CURRENT (µA)

20

0

0.8

TA = 85°C

TA = 0°C

1.0
INPUT VOLTAGE (V)

1.2

= 70°C

T

A

TA = 25°C

T

1.4

Maximum Start-Up Load Current
vs Input Voltage

16

TA = 25°C

12

8

LOAD CURRENT (mA)

4

0

0.8

1.0
INPUT VOLTAGE (V)

1.2

1.4

= –40°C

A

1.6

1.6

1502-3.3 G01

1502-3.3 G04

1.8

1.8

Shutdown Input Current
vs Input Voltage

16

–

/SHDN = 0V

C1

12

8

TA = 70°C

INPUT CURRENT (µA)

4

0

1.0

0.8

T

T

= – 40°C

A

1.2

INPUT VOLTAGE (V)

Efficiency vs Output Current

100

TA = 25°C

= 3.3V

V

OUT

80

60

40

EFFICIENCY (%)

20

0

0.01

0.1
OUTPUT CURRENT (mA)

1

= 85°C

A

1.4

T

A

TA = 25°C

= 0°C

1.6

= 1V

V

IN

VIN = 1.25V
VIN = 1.5V

VIN = 1.8V

10

1502-3.3 G05

1502-3.3 G02

100

1.8

Output Voltage vs Output Current

3.40

3.35

3.30

OUTPUT VOLTAGE (V)

3.25

3.20

0.01

I

OUT

0mA to 10mA

5mA/DIV

V

OUT

AC COUPLED

50mV/DIV

= 25°C

T

A

VIN = 1.5V

V

= 1V

IN

0.1
OUTPUT CURRENT (mA)

= 1.8V

V

IN

1

10

Load Transient Response

VIN = 1.25V
T

= 25°C

A

200µs/DIV

100

1502-3.3 G03

1502-3.3 G06

Oscillator Frequency
vs Input Voltage

700

600

500

400

OSCILLATOR FREQUENCY (kHz)

300

0.8

1.0

TA = 85°C

TA = – 40°C

1.2

INPUT VOLTAGE (V)

TA = 70°C
TA = 25°C

TA = 0°C

1.4

1.6

1502-3.3 G07

1.8

Calculated Battery Life,
Battery = 2400mA • Hr AA Cell

100k

10k

1k

BATTERY LIFE (HOURS)

100

10

0.001

0.1 1 100.01 100

AVERAGE LOAD CURRENT (mA)

1502-3.3 G08

Shutdown Waveforms
(See Figure 1)

V

OUT

2V/DIV

OFF

V

CTRL

ON

V

= 1.25V

IN

R

= 10k

LOAD

= 25°C

T

A

100µs/DIV

1502-3.3 G09

3