LM3554 datasheet(4/43 Pages) TI1

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LM3554

SNVS549A – JUNE 2009 – REVISED APRIL 2011

www.ti.com

Operating Ratings

(1) (2)

VIN

2.5V to 5.5V

Junction Temperature (TJ)

-30°C to +125°C

Ambient Temperature (TA)

(3)

-30°C to +85°C

(1)

Absolute Maximum Ratings indicate limits beyond which damage to the device 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 table.

(2)

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

(3)

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 (TA-MAX) is dependent on the maximum operating junction temperature (TJ-MAX-OP =

+125°C), the maximum power dissipation of the device in the application (PD-MAX), and the junction-to-ambient thermal resistance of the

part/package in the application (

θJA), as given by the following equation: TA-MAX = TJ-MAX-OP – (θJA × PD-MAX).

Thermal Properties

Junction-to-Ambient Thermal Resistance (

θJA), TMD16 Package

(1)

60°C/W

(1)

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 2x1 array of

thermal via's. 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.

Electrical Characteristics

Limits in standard typeface are for TA = +25°C. Limits in boldface type apply over the full operating ambient temperature

range (-30°C

≤ TA ≤ +85°C). Unless otherwise specified, VIN = 3.6V, VHWEN = VIN.

(1) (2)

Symbol

Parameter

Conditions

Min

Typ

Max

Units

Current Source Specifications

600mA Flash

ILED1+ILED2

1128

1200

1284

LED Setting,

ILED1 or ILED2

541

600

657

VOUT = VIN

Current Source

ILED

Accuracy

17mA Torch

Current Setting, ILED1+ILED2

30.4

33.8

37.2

VHR = 500mV

Current Source

Regulation

VHR

600mA setting, VOUT = 3.75V

300

Voltage (VOUT -

VLED)

LED Current

IMATCH

600mA setting, VLED = 3.2V

0.35

Matching

Step-Up DC/DC Converter Specifications

Output Voltage

2.7V

≤ VIN ≤ 4.2V, IOUT = 0mA,

VREG

4.8

5.2

Accuracy

VENVM = VIN, OV bit = 0

Output Over-

On Threshold, 2.7V

≤ VIN ≤ 5.5V

5.4

5.6

5.7

Voltage

VOVP

Protection Trip

Off Threshold

5.3

Point(3)

PMOS Switch

RPMOS

IPMOS = 1A

150

Ω

On-Resistance

NMOS Switch

RNMOS

INMOS = 1A

150

Ω

On-Resistance

(1)

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

(2)

Min and Max limits are guaranteed by design, test, or statistical analysis. Typical (Typ) numbers are not guaranteed, but do represent

the most likely norm. Unless otherwise specified, conditions for typical specifications are: VIN = 3.6V and TA = +25°C.

(3)

The typical curve for Over-Voltage Protection (OVP) is measured in closed loop using the typical application circuit . The OVP value is

found by forcing an open circuit in the LED1 and LED2 path and recording the peak value of VOUT. The value given in the Electrical

Table is found in an open loop configuration by ramping the voltage at OUT until the OVP comparator trips. The closed loop data can

appear higher due to the stored energy in the inductor being dumped into the output capacitor after the OVP comparator trips. At worst

case is an open circuit condition where the output voltage can continue to rise after the OVP comparator trips by approximately

IIN×sqrt(L/COUT).

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