Linear Technology LTC1986 Datasheet

FEATURES

■

VIN Range: 2.6V to 4.4V

■

Step-Up Charge Pump Generates 5V

■

Output Current: 10mA

■

VIN to V

■

Ultralow Power

Direct Connection for 3V SIMs

OUT

Operating Current: 14µA
Shutdown Current: <1µA

■

No Inductors

■

Short-Circuit/Thermal Protected

■

Switching Frequency: 900kHz

■

Soft-Start Limits Inrush Current at Turn-On

■

Output Driven to Ground During Shutdown

■

Ultrasmall Application Circuit (<0.045in2)

■

6-Lead SOT-23 Package

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APPLICATIO S

■

GSM Cellular Telephones

■

PCS/DCS Cellular Telephones

■

Portable POS Terminals

LTC1986

3V/5V SIM Power Supply

in SOT-23

U

DESCRIPTIO

The LTC®1986 is a micropower charge pump DC/DC
converter that provides power for either 3V or 5V GSM
SIM cards. It operates in one of three modes: V
(5V mode), V

= VIN (3V mode) or shutdown. The input

OUT

voltage range is 2.6V to 4.4V and the part can provide
10mA of output current. The LTC1986 allows VIN to drop
as low as 2.6V by providing a boost feature in 3V mode. In
3V mode, V

is connected directly to VIN through a 2.5Ω

OUT

switch until VIN drops below 2.85V. When VIN is below

2.85V, the part automatically boosts V
regulated 2.9V output, thereby ensuring V

to maintain a

OUT

stays within

OUT

the 3V SIM VCC specification.
Extremely low operating current (14µA typical with no

load) and low external parts count make the part ideally
suited for small, light load battery-powered applications.
The total PCB area of the application circuit shown below
is less than 0.045in2. Protection features include inrush
current limiting, undervoltage lockout, short circuit and
thermal overload protection. The LTC1986 is available in
a 6-lead SOT-23 package.

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

OUT

= 5V

TYPICAL APPLICATIO

3V/5V SIM Power Supply

V

= 5V

OUT

OR V

IN

GSM

CONTROLLER

3/5

SHDN

2.2µF

1M

750k

1

2

3

V

GND

MODE

SHDN

0
0
1
1

U

LTC1986

OUT

3/5

V

IN

+

C1

–

C1

0

SHUTDOWN

1

SHUTDOWN
0
1

V

= 2.6V TO 4.4V

IN

6

5

4

MODE

= 5V

V

OUT

= V

V

OUT

Output Voltage vs Input Voltage

6

TA = 25°C
I

= 10mA

OUT

0.1µF

0.047µF

IN

1986 TA01

5

4

OUTPUT VOLTAGE (V)

3

2

2.5

3.0

3V MODE

(V

OUT

INPUT VOLTAGE (V)

= VIN)

3.5

5V MODE

4.0

4.5

1986 TA02

1

LTC1986

WW

W

ABSOLUTE MAXIMUM RATINGS

U

U

W

PACKAGE/ORDER INFORMATION

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(Note 1)

VIN, V

to GND .........................................–0.3V to 6V

OUT

All Other Pins to GND ..................................–0.3V to 6V

V

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

OUT

Operating Temperature Range

(Note 2) .................................................. – 40°C to 85°C

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

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

TOP VIEW

V

1

OUT

GND 2

MODE 3

S6 PACKAGE

6-LEAD PLASTIC SOT-23

T

= 125°C, θJA = 230°C/ W

JMAX

Consult factory for Military grade parts.

6 V
5 C1
4 C1

IN

+

–

ORDER PART

NUMBER

LTC1986ES6

S6 PART MARKING

LTKX

ELECTRICAL CHARACTERISTICS

The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C.
VIN = V

PARAMETER CONDITIONS MIN TYP MAX UNITS

V

IN

VOUT

V

IN

VIN-to-V
V

OUT

V

OUT

Switching Frequency Oscillator Free-Running 900 kHz
MODE Input Ranges Shutdown Mode

MODE Input Current ● –1 1 µA
Undervoltage Lockout Threshold 1.4 V

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

to V

MIN

Operating Voltage ● 2.6 4.4 V

Output Voltage Shutdown Mode 0 V

Operating Current Shutdown Mode, V

ON Resistance 3V Mode, VIN = 3V ● 2.5 5 Ω

OUT

Short-Circuit Current 3V or 5V Mode, V
Discharge Resistance ● 70 200 Ω

, MODE = VIN, C1 = 0.047µF, C

MAX

= 2.2µF, unless otherwise specified.

OUT

3V Mode. V
3V Mode, V
5V Mode, V
5V Mode, VIN = 2.7V to 4.4V, I

3V Mode, I
5V Mode, I

5V Mode
3V Mode ● V

= 2.85V to 4.4V, I

IN

< 2.85V, I

IN

< 2.7V, I

IN

= 0mA ● 10 25 µA

OUT

= 0mA ● 14 30 µA

OUT

OUT

≤ 10mA ● 4.55 5 5.25 V

OUT

= 0V ● 0.001 1 µA

MODE

= 0V ● 20 100 200 mA

OUT

Note 2: The LTC1986 is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.

≤ 10mA V

OUT

< 10mA ● 2.75 2.9 3.05 V

≤ 10mA ● 4.75 5 5.25 V

OUT

● 0V

● V

– 0.025 V

IN

/2 + 0.1 V

IN

– 0.25 V

IN

/2 – 0.1 V

IN

– 1.0 V

IN

IN

V

2

W

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TYPICAL PERFORMANCE CHARACTERISTICS

Output Voltage vs Output Current
(3V Mode)

3.10

3.05

VIN = V
T

A

= 25°C

MODE

= 3V

Efficiency vs Input Voltage

100

80

LTC1986

I

= 10mA

OUT

V

= 5V

OUT

= 25°C

T

A

3.00

OUTPUT VOLTAGE (V)

2.95

2.90

0.001

0.01
OUTPUT CURRENT (mA)

0.1

Efficiency vs Output Current

100

80

60

40

EFFICIENCY (%)

20

0

0.001

VIN = 3V
5V MODE (V
T

= 25°C

A

0.01

0.1

OUTPUT CURRENT (mA)

MODE

1

1986 G01

= 0.6VIN)

1

1986 G03

60

EFFICIENCY (%)

40

20

10

2.5

3.0

3.5

INPUT VOLTAGE (V)

4.0

4.5

1986 G02

Positive Supply Current vs
Input Voltage

40

30

20

5V MODE (V

10

0

3V MODE (V

2.5

POSITIVE SUPPLY CURRENT (mA )

10

MODE

MODE

3.0
INPUT VOLTAGE (V)

= 0.6VIN)

= VIN)

3.5

I

OUT

T

A

= 0mA

= 25°C

4.0

4.5

1986 G04

V

OUT

50mV/DIV

AC COUPLED

Output Voltage Ripple
(5V Mode)

= 3V

V

IN

= 10mA

I

OUT

T

= 25°C 1986 G05

A

5ms/DIV

V

OUT

2V/DIV

V

MODE

2V/DIV

Output Voltage vs
V

Waveforms

MODE

5V

0V
4V

0V

= 4V

V

IN

= 25°C 1986 G06

T

A

2ms/DIV

3