LM3554TMXSLASHNOPB datasheet(29/47 Pages) TI1

29 / 47 page

HWEN

SCL

SDA

STROBE

TX1/TORCH/

GPIO1

OUT

GND

LED1

LED2

LEDI/NTC

Optional fixed 4.5-V or 5-V DC

power rail or adaptive mode for

white LED bias

Flash

LEDs

Indicator

LED

ENVM/TX2

/GPIO

VBIAS

0.1 µF

RBIAS

4.7 µF

2.2 µH

NŸ

Thermistor

2.5 V

± 5.5 V

LM3554

www.ti.com

SNVS549C – JUNE 2009 – REVISED FEBRUARY 2016

Product Folder Links: LM3554

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8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The LM3554 is a dual-string white-LED driver for LED camera flash applications. The dual high-side current

sources allow for grounded cathode LEDs. The integrated boost provides the power for the current sources and

can source up to 1.2 A from a single-cell Li+ voltage range.

8.2 Typical Application

Figure 41. LM3554 Typical Application

8.2.1 Design Requirements

For typical LM3554 device applications, use the parameters listed in Table 10.

Table 10. Design Parameters

DESIGN PARAMETER

EXAMPLE VALUE

Minimum input voltage

2.5 V

Programmable output voltage

4.5 V or 5 V

Programmable output current

37.5 mA to 1.2 A

Table 11. Application Circuit Component List

COMPONENT

MANUFACTURER

VALUE

PART NUMBER

SIZE (mm)

RATING

TOKO

2.2 µH

FDSE0312-2R2M

3 × 3 × 1.2

2.3 A (0.2

Ω)

COUT

Murata

4.7 µF/10 µF

GRM188R60J475M,

GRM188R60J106M

0603 (1.6 × 0.8 ×0.8 )

6.3 V

CIN

Murata

4.7 µF

GRM185R60J475M

0603 (1.6 × 0.8 × 0.8

)

6.3 V

LEDs

Lumiled

LXCL-PWF4

1.5 A

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