National Semiconductor LM2753 Technical data

November 2006

LM2753 High Power Switched Capacitor Voltage Convertor/Flash LED Driver

General Description

The LM2753 is capable of driving a Flash LED with a pulsed current of 400mA at an input voltage of 3.6V. A switched capacitor doubler, the LM2753 provides a regulated 5V output (V

) over an input supply range of 3.0V to 5.5V. The

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switched output, I provide maximum current to a Flash LED. Flash LED current is set via a ballast resistor. Continuous illumination current (Torch Mode) is programmed by connecting a resistor between I cost ceramic capacitors.

LM2753 uses Pulse Frequency Modulation (PFM) regulation. Typical operating frequency is 725kHz. Under no-load conditions, LM2753 operates on only 60µA. If the output is connected to ground, the charge pump stays in the gain of 1 which helps limit the input current to 300mA (typ.)

LM2753 is available in a 10-pin No Pullback Leadless Leadframe Package: LLP-10.

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and V

, takes less than 10ns to turn on and

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. This device uses only three small, low-

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Typical Application Circuit

Features

Input Voltage Range: 3.0V to 5.5V

■

Regulated 5V Output

■

250mA Output Current with a 3.6V input

■

400mA Pulsed Output Current (up to 500ms duration)

■

60µA (typ.) Quiescent Current

■

PFM Regulation

■

Inductor-less solution: requires only 3 small capacitors

■

<1µA Typical Shutdown Current

■

10-pin LLP Package (No Pullback):

■

3mm x 3mm x 0.8mm

Applications

Cell Phone Camera Flash

■

General Purpose Regulated Voltage Output, High Current

■

Supply

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Connection Diagram

LM2753

Pin Descriptions

Pin # Name Description

1 C

2 V

3 C

4 FLASH Flash Logic Input Pin. Logic HIGH = Flash Output On, Logic LOW = Flash Output Off. There

5 GND Connect to Ground.

6 EN Enable Pin. Logic HIGH = Enable, Logic LOW = Shut Down. There is an internal pulldown

7 GND Connect to Ground.

8 I

9 V

10 GND Connect to Ground

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10-Pin LLP Package (LLP10) No Pullback

NS Package Number SDA10A

Flying capacitor connection.

Input Voltage Connection. Input Voltage Range: 3.0V to 5.5V.

Flying Capacitor connection.

is an internal pulldown of 300kΩ between FLASH and GND.

of 300kΩ between EN and GND

Flash Output. On/Off Control via FLASH Pin.

5V Regulated Output.

LM2753

3mm X 3mm x 0.8mm

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Ordering Information

Output Voltage Ordering Number Package Mark ID Package Supplied As

5.0V LM2753SD D004B SDA10A

5.0V LM2753SDX D004B 4500 Units, Tape and

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Non-Pullback

LLP

1000 Units, Tape and

Reel

LM2753

Absolute Maximum Ratings (Notes 1, 2)

If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.

If Military/Aerospace specified devices are required, please contact the National semiconductor Sales/Office/Distributors for availability and specifications.

VIN Pin: Voltage to Ground

EN, Flash pins: Voltage to GND −0.3V to (VIN+0.3)

Continuous Power Dissipation (Note

3) Internally Limited Junction Temperature (T

J-MAX-ABS

)

−0.3V to 6.0V

w/ 6.0V max

150°C

Operating Ratings (Notes 1, 2)

Input Voltage Range 3.0V to 5.5V EN, Flash Input Voltage Range 0V to V

Junction Temperature (TJ) Range

Ambient Temperature (TA) Range

-40°C to 120°C

-40°C to 85°C

(Note 5)

Thermal Properties

Junction-to-Ambient Thermal Resistance, LLP-10 55°C/W

Package (θJA) (Note 6)

Storage Temperature Range −65°C to 150°C Maximum Lead Temperature 265°C (Soldering, 10sec.) ESD Rating (Note 4)

Human-body model: Machine model:

2kV

200V

Electrical Characteristics (Notes 2, 7)

Limits in standard typeface are for TA = 25ºC. Limits in boldface type apply over the full operating ambient temperature range (-40° C ≤ TA ≤ +85°C) . Unless otherwise noted, specifications apply to the LM2753 Typical Application Circuit (pg. 1) with: VIN = 3.6V,

V(EN) = V

Symbol Parameter Conditions Min Typ Max Units

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VOUT

OUT

FLASH

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the component may occur. Operating Ratings are conditions under which operation of the device is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see the Electrical Characteristics tables.

Note 2: All voltages are with respect to the potential at the GND pin.

Note 3: Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ=125°C (typ.).

Note 4: The Human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. The machine model is a 200pF capacitor discharged

directly into each pin. MIL-STD-883 3015.7

V(FLASH) = GND, C1 = 1.0µF, CIN = C

IN,

Output Voltage

Continuous Load Current

Pulsed Flash Current V(FLASH) = 1.8V

Quiescent Current I

= 10.0µF (Note 8).

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3.0V ≤ VIN ≤ 5.5V,

≤ 100mA

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3.0V ≤ VIN ≤ 5.5V V

= 5V (typ.)

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= 500ms

PULSE

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IOUT-MAX

= 0mA

= 4.1V (typ.)

4.75

(-5%)

5.0 5.25 (+5%)

200 mA

400 mA

60 80 µA

3.0V ≤ VIN ≤ 5.5V

Shutdown Supply Current V(EN) = 0V

0.1 1 µA

3.0V ≤ VIN ≤ 5.5V

V(EN) = 0V

0.2

3.0V ≤ VIN ≤ 5.5V TA = 85°C

Output Impedance VIN = 3.2V 5.3

Switching Frequency

3.0V ≤ VIN ≤ 5.5V

475 725 950

Logic Input High Input Pins: EN, FLASH 1.20 V

Logic Input Low Input Pins: EN, FLASH 0 .30 V

Logic Input High Current V(EN) = V(FLASH) = 3.0V 10 µA

Logic Input Low Current V(EN) = V(FLASH) = 0V 10 nA

Turn-On Time (Note 9) 640 µs

Flash Turn-On Time (Note 10) V(FLASH) = 3.6V 10 ns

Ω

kHz

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Note 5: In applications where high power dissipation and/or poor package thermal resistance is present, the maximum ambient temperature may have to be derated. Maximum ambient temperature (T dissipation of the device in the application (P

LM2753

following equation: T

A-MAX

= T

J-MAX-OP

- (θJA × P

) is dependent on the maximum operating junction temperature (T

A-MAX

), and the junction-to ambient thermal resistance of the part/package in the application (θJA), as given by the

D-MAX

= 120ºC), the maximum power

J-MAX-OP

Note 6: Junction-to-ambient thermal resistance (θJA) is taken from a thermal modeling result, performed under the conditions and guidelines set forth in the JEDEC standard JESD51-7. The test board is a 4 layer FR-4 board measuring 102mm x 76mm x 1.6mm with a 2 x 1 array of thermal vias. The ground plane on the board is 50mm x 50mm. Thickness of copper layers are 36µm/18µm /18µm/36µm (1.5oz/1oz/1oz/1.5oz). Ambient temperature in simulation is 22°C, still air. Power dissipation is 1W.

The value of θ conditions. In applications where high maximum power dissipation exists (high VIN, high I information on these topics, please refer to Application Note 1187: Leadless Leadframe Package (LLP) and the Power Efficiency and Power Dissipation

of the LM2753 in LLP-10 could fall in a range as wide as 50ºC/W to 150ºC/W (if not wider), depending on PWB material, layout, and environmental

), special care must be paid to thermal dissipation issues. For more

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section of this datasheet.

Note 7: Min and Max limits are guaranteed by design, test, or statistical analysis. Typical numbers are not guaranteed, but represent the most likely norm.

Note 8: CIN, C

Note 9: Turn-on time is measured from when the EN signal is pulled high until the output voltage on V

Note 10: Flash Turn-on time is measured from when the FLASH signal is pulled high until the voltage on I

, and C1: Low-ESR Surface-Mount Ceramic Capacitors (MLCCs) used in setting electrical characteristics.

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crosses 90% of its final value.

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crosses 90% of its final programmed value.

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Block Diagram

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