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SiP12502

Vishay Siliconix

500 mA - Fixed Output Boost Converter for Single or Dual Cell

DESCRIPTION

SiP12502 is a boost converter IC with fixed output voltage for

single or double cell NiMH or Alkaline battery pack. Featuring

with an internal low resistance power MOSFET, it is capable

of starting up with a low battery voltage of 0.85 V. It only

needs four external components (an inductor, a diode and

two capacitors) to construct a step-up converter. For best

efficiency performance, it is designed to operate in PWM

mode with a 300 kHZ switching frequency under normal load

and in PFM mode under light load. The voltage-mode control

loop is internally compensated, simplifying converter design

and reducing external parts count. It accepts input voltages

from 0.85 V to 5 V, providing fixed output voltages of 2.0 V,

3.3 V, and 5.0 V. It also features low shutdown current of

under 1 µA, over voltage protection, thermal shutdown

protection, a power good output and antiringing control to

minimize EMI.

SiP12502 is available in a lead (Pb)-free 6-pin, PowerPAK

MLP33 package and is specified to operate over the

industrial temperature range of - 40 °C to 85 °C.

FEATURES

• Voltage mode control with internal frequency

compensation

• 0.85 V to 5.0 V input voltage range

• Fixed output voltage options - 2.0 V, 3.3 V, and 5.0 V

• Other voltages available upon request

• PWM control with 300 kHz fixed switching frequency

• PFM control for light load

• Powered from the output voltage supply

• Integrated UVLO and soft-start

• Logic controlled shutdown (< 1 µA)

• 85 % typical efficiency

• Internal power MOS switch: 0.2

Ω

at 3.3 V output

• Antiringing switch to minimize EMI

• Power good output

• Shutdown input

• Minimum external components

• PowerPAK

®

MLP33-6 package, (DFN-6, 3 x 3)

• Over voltage protection

APPLICATIONS

•

Portable applications

Battery-powered equipment

Handheld devices

Digital cameras

Wireless handsets

LCD and OLED bias

TYPICAL APPLICATION CIRCUIT

V

IN

10 µH

10 µF

2

V

IN

XSHD

1

XSHD

LX

6

MBR0520

V

OUT

47 µF

SiP12502

3

V

OUT

GND

5

4

PGOOD

330 KΩ

PGOOD

Document Number: 73578

S09-1456-Rev. B, 03-Aug-09

www.vishay.com

1

SiP12502

Vishay Siliconix

ABSOLUTE MAXIMUM RATINGS

(all voltages referenced to GND = 0 V)

Parameter

Input Voltage, V

IN

LX Voltage

Output Voltage, V

OUT

XSHD Voltage

PGOOD Voltage

Maximum Junction Temperature

Storage Temperature

Operating Junction Temperature

Power Dissipation

a

Thermal Resistance

b

PowerPAK MLP33-6 (T

A

= 70

PowerPAK MLP33-6

°C)

a

Limit

- 0.3 to 6

- 0.3 to V

OUT

+ 0.5

- 0.3 to 6

- 0.3 to V

IN

+ 0.5

- 0.3 to 6

150

- 55 to 150

125

1100

50

mW

°C/W

°C

V

Unit

Notes:

a. Derate 20 mW/°C above 70 °C.

b. Device mounted with all leads soldered or welded to PC board.

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation

of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum

rating conditions for extended periods may affect device reliability.

RECOMMENDED OPERATING RANGE

(all voltages referenced to GND = 0 V)

Parameter

Input Voltage, V

IN

Output Voltage, V

OUT

XSHD Voltage

LX Voltage

PGOOD Voltage

Operating Temperature Range

Limit

0.85 to 5.0

2.0 to 5

0 to V

IN

0 to V

OUT

+ 0.5

0 to 5

- 40 to 85

°C

V

Unit

SPECIFICATIONS

Test Conditions Unless Specified

Parameter

Minimum Start-Up Voltage

Minimum Operating Voltage

d

Symbol

V

START

VH

OLD

V

IN

= 1.2 V, V

OUT

= V

nom

, T

A

= 25 °C

I

LOAD

= 1 mA

XSHD = V

IN

- 1.5

Output Voltage Accuracy

V

OUT

- 25 °C

to 85 °C

Full

UVLO

UVLO Hysteresis

Maximum PWM Duty Cycle

PWM Switching Frequency

V

UVLO

V

UVLOHYST

MAXDTY

f

OSC

Rising V

OUT

Full

80

225

- 3.0

- 3.5

1.8

0.100

87

300

375

e

Limits

Temp.

a

Full

Min.

b

Typ.

c

0.65

0.55

+ 1.5

+ 3.0

+ 3.5

2

V

%

kHz

%

Max.

b

0.85

Unit

V

www.vishay.com

2

Document Number: 73578

S09-1456-Rev. B, 03-Aug-09

SiP12502

Vishay Siliconix

SPECIFICATIONS

Test Conditions Unless Specified

Parameter

Supply Current 1

Supply Current 2

Supply Current 3

Stand-By Current

NMOS Switch Leakage

NMOS Switch On Resistance

PWM to PFM Current Threshold

PFM to PWM Current Threshold

XSHD Input High Level

XSHD Input Low Level

Softstart Time

Over Voltage Threshold

Over Voltage Hysteresis

Thermal Shutdown

Thermal Shutdown Hysteresis

PGOOD Threshold

PGOOD Hysteresis

PGOOD Output Voltage Low

PGOOD Output Leakage Current

Symbol

I

OUT1

I

OUT2

I

OUT3

I

STB

I

LEAK

R

DS(on)

I

WTOF

I

FTOF

0.8 V

≤

V

IN

≤

0.9 V

V

XSHDH

V

XSHDL

t

START

V

OV

V

OVHYST

T

SHD

T

HYST

V

PGOOD

V

PGOODHYST

PG

GOODL

PG

GOOD

V

OUT

= 3.3 V, I

PGOOD

= 1 mA

V

PGOOD

= 5 V

Full

85

V

iN

= 1.8 V

0.9 V < V

IN

≤

2 V

2 V < V

IN

≤

5 V

Full

1.6

110

10

160

20

90

2

0.15

0.01

0.2

1

95

0.55

0.8

1.2

0.2

ms

%

°C

%

V

µA

V

IN

= 1.2 V, V

OUT

=

V

nome

,

T

A

= 25 °C

Temp.

a

Full

Min.

b

V

OUT

= V

nom

X 0.95

V

OUT

= 6 V, V

nom

+ 0.6 V, V

LX

> V

IN

V

OUT

= V

nom

+ 0.5 V, V

LX

< V

IN

XSHD = 0 V, not including switch leakage

LX = 5 V

V

OUT

= 3.3 V

Full

1

Full

0.2

3

22

Limits

Typ.

c

330

150

75

1

2

10

Ω

mA

µA

Max.

b

620

Unit

Notes:

a. Full = - 40 °C to 85 °C.

b. The algebraic convention whereby the most negative value is a minimum and the most positive a maximum (- 40 °C to 85 °C).

c. Typical values are for DESIGN AID ONLY, not guaranteed nor subject to production testing.

d. Minimum operating voltage is determined by the battery’s capability to provide energy as it is deeply discharged.

e. V

nom

equals voltage output for part selected.

Document Number: 73578

S09-1456-Rev. B, 03-Aug-09

www.vishay.com

3

SiP12502

Vishay Siliconix

PIN CONFIGURATION AND TRUTH TABLE

PowerPAK MLP33-6

XSHD

1

6

LX

V

IN

2

5

GND

V

OUT

3

4

PGOOD

Top View

ORDERING INFORMATION

Part Number

SiP12502DMP-20-E3

SiP12502DMP-33-E3

SiP12502DMP-50-E3

Voltage Output

2.0 V

3.3 V

5.0 V

- 40 °C to 85 °C

Temperature Range

Marking

502A

502E

502G

PIN DESCRIPTION

Pin Number

1

2

3

4

5

6

Name

XSDH

V

IN

V

OUT

PGOOD

GND

LX

Input voltage

Output of the boost converter and power source for the IC battery

Power good comparator output

Signal and power ground

Switch pin

Function

Logic controlled shutdown input, XSHD = high: normal operation, XSHD = low: shutdown

PIN FUNCTIONS

XSHD (Pin 1)

XSHD is a logic-level shutdown control pin. When XSHD is

low, the IC’s switching is disabled and an antiringing switch

is connected between LX and V

IN

. When XSHD is high, the

IC is working in normal operation.

V

IN

(Pin 2)

V

IN

is the pin connected to the battery input voltage. At start-

up, SIP12502 is powered from the voltage at the V

IN

pin.

Once V

OUT

exceeds V

IN

, the SIP12502 is powered from

V

OUT

. This increases the drive to the gate of the internal

power switch, to allow higher maximum output currents and

higher converter efficiency.

V

OUT

(Pin 3)

V

OUT

is the output of the boost converter and also the power

source for the IC.

GND (Pin 5)

GND is the ground pin for signal and power ground.

LX (Pin 6)

LX is connects to the drain of the internal power MOSFET

(boost switch). Externally, the LX pin should be connected to

the boost inductor and Schottky diode. If the inductor current

falls to zero, or XSHD is low, an internal antiringing switch is

connected from LX to V

IN

to minimize EMI.

PGOOD (Pin 4)

PGOOD is the open-drain output pin of the power good

comparator. It is low when V

OUT

is 10 % lower than its

regulation voltage. After the soft start is finished and V

OUT

is

higher than 90 % of its regulation voltage, PGOOD will go

high. Its hysteresis is 2 %.

www.vishay.com

4

Document Number: 73578

S09-1456-Rev. B, 03-Aug-09

SiP12502

Vishay Siliconix

FUNCTIONAL BLOCK DIAGRAM

DETAILED OPERATION

SiP12502 is a 300 kHz boost converter IC, packaged in 6-pin

MLP33 PowerPAK

TM

package. With start-up from input

voltages as low as 0.65 V, this device features fixed

frequency voltage mode PWM control with internal frequency

compensation. With its low r

DS(on)

internal power MOSFET,

this device maintains high efficiency over a wide range of

load currents. Under light load conditions, it switches to PFM

mode to maintain high efficiency. A power good signal is

available to monitor the output voltage.

Low Voltage Start-Up

SiP12502 is designed to start-up at input voltage of typically

0.65 V. At start-up, V

OUT

is lower than V

IN

due to the voltage

drop of the Schottky diode. Therefore, the device uses V

IN

as

the power source for its control logic and internal gate drive,

until V

OUT

exceeds V

IN

. During the start-up interval, the

boost switch’s conduction interval during each cycle is

determined by the time taken for the inductor current to reach

internal current limit, followed by a fixed off time before the

switch is allowed to turn on again. Once V

OUT

exceeds V

IN

,

the device uses V

OUT

as the IC’s power source. When V

OUT

exceeds 1.89 V, the device engages its built-in soft-start

circuitry.

Soft-Start

During soft-start, the loop compensation guarantees the slow

increase of output voltage, so that no large voltage overshoot

or inrush current transients occur when the soft-start period

ends.

Over Voltage Protection

If the output voltage is above 10 % of the regulation voltage,

the device will turn off the internal power MOSFET and wait

until the output voltage falls below the regulation voltage,

then the PWM operation is enabled again.

Thermal Shutdown Protection

If the internal device temperature rises above 160 °C, the

device will turn off the internal power MOSFET. Once the die

temperature falls below 140 °C, the device performs a new

soft-start cycle, the converter resumes normal operation.

Antiringing Control

The antiringing control circuitry prevents high frequency

ringing at the LX pin as the inductor current goes to zero by

damping the resonant circuit formed by L and C

LX

(capacitance on LX pin). When the IC is shutdown, this

antiringing switch is also turned on.

PWM operation

After the soft-start interval is over, the device works in PWM

operation with a fixed frequency of 300 kHz, with automatic

switch-over to PFM operation during light load conditions.

PFM Operation

When operating into light loads, the SiP12502 automatically

switches to PFM operation. This reduces gate charge losses

in the boost switch, hence raising converter efficiency.

Document Number: 73578

S09-1456-Rev. B, 03-Aug-09

www.vishay.com

5

SIP12502

SIP12502概述

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