LM3503SQ-35/NOPB - Texas Instruments

LM3503-44

VIN Sw

En1

En2

Cntrl

AGND PGND

VOUT1

VOUT2

22 PHD

CIN

4.7 PFCOUT

1 PF

VSUPPLY

MAIN:

2 to 5

LEDs

SUB:

2 to 5

LEDs

Logic

Voltage

Signal

Inputs

LM3503

www.ti.com

SNVS329E –JULY 2005–REVISED MAY 2013

LM3503 Dual-Display Constant Current LED Driver with Analog Brightness Control

Check for Samples: LM3503

1FEATURES APPLICATIONS

2• Drives up to 4, 6, 8 or 10 White LEDs for Dual • Dual Display Backlighting in Portable devices

Display Backlighting • Cellular Phones and PDAs

• >80% Peak Efficiency DESCRIPTION

• Output Voltage Protection Options: 16V, 25V, The LM3503 is a white LED driver for lighting

35V & 44V applications. For dual display backlighting

• Input Under-Voltage Protection applications, the LM3503 provides a complete

• Internal Soft Start Eliminates Inrush Current solution. The LM3503 contains two internal white LED

current bypass FET (Field Effect Transistor) switches.

• 1 MHz Constant Switching Frequency The white LED current can be adjusted with a DC

• Analog Brightness Control voltage from a digital to analog converter or RC

• Wide Input Voltage Range: 2.5V to 5.5V filtered PWM (pulse-width-modulated) signal at the

• Low Profile Packages: <1 mm Height Cntrl pin.

– 10 Bump DSBGA

– 16 Pin WQFN

Typical Application

1Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2All trademarks are the property of their respective owners.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

B1 B3

C1 C3

1234

9 10 11 12

LM3503

SNVS329E –JULY 2005–REVISED MAY 2013

www.ti.com

DESCRIPTION (CONTINUED)

With no external compensation, cycle-by-cycle current limit, output over-voltage protection, input under-voltage

protection, and dynamic white LED current control capability, the LM3503 offers superior performance over other

step-up white LED drivers.

Connection Diagram

Figure 1. 10-Bump Thin DSBGA Package Figure 2. 16-Lead Thin WQFN Package

(YPA0010) (Top View) (RGH0016A) (Top View)

PIN DESCRIPTIONS

Bump # Pin # Name Description

A1 9 Cntrl White LED Current Control Connection

B1 7 Fb Feedback Voltage Connection

C1 6 VOUT2 Drain Connections of the NMOS and PMOS Field Effect Transistor (FET) Switches (Figure 3: N2 and

P1). Connect 100nF at VOUT2 node if VOUT2 is not used

D1 4 VOUT1 Over-Voltage Protection (OVP) and Source Connection of the PMOS FET Switch (Figure 3: P1)

D2 2 and 3 Sw Drain Connection of the Power NMOS Switch (Figure 3: N1)

D3 15 and 16 Pgnd Power Ground Connection

C3 14 Agnd Analog Ground Connection

B3 13 VIN Input Voltage Connection

A3 12 En2 NMOS FET Switch Control Connection

A2 10 En1 PMOS FET Switch Control Connection

1 NC No Connection

5 NC No Connection

8 NC No Connection

11 NC No Connection

DAP DAP Die Attach Pad (DAP), to be soldered to the printed circuit board’s ground plane for enhanced

thermal dissipation.

Cntrl (Bump A1): White LED current control pin. Use this pin to control the feedback voltage with an external

DC voltage.

Fb (Bump B1):Output voltage feedback connection.

VOUT2 (Bump C1):Drain connections of the internal PMOS and NMOS FET switches (Figure 3: P1 and N2). It is

recommended to connect 100nF at VOUT2 if VOUT2 is not used for LM3503-35V & LM3503-44V versions.

VOUT1(Bump D1):

Source connection of the internal PMOS FET switch (Figure 3: P1) and OVP sensing node. The output capacitor

must be connected as close to the device as possible, between the VOUT1 pin and ground plane. Also connect

the Schottky diode as close as possible to the VOUT1 pin to minimize trace resistance and EMI radiation.

Sw (Bump D2):

Product Folder Links: LM3503

LM3503

www.ti.com

SNVS329E –JULY 2005–REVISED MAY 2013

Drain connection of the internal power NMOS FET switch (Figure 3: N1). Minimize the metal trace length and

maximize the metal trace width connected to this pin to reduce EMI radiation and trace resistance.

Pgnd (Bump D3): Power ground pin. Connect directly to the ground plane.

Agnd (Bump C3):Analog ground pin. Connect the analog ground pin directly to the Pgnd pin.

VIN (Bump B3): Input voltage connection pin. The CIN capacitor should be as close to the device as possible,

between the VIN pin and ground plane.

En2 (Bump A3): Enable pin for the internal NMOS FET switch (Figure 3: N2) during device operation. When

VEn2 is ≥1.4V, the internal NMOS FET switch turns off and the SUB display is turned on. The En2 pin has an

internal pull down circuit, thus the internal NMOS FET switch is normally in the on state of operation with the

SUB display turned off. When VEn2 is ≤0.3V, the internal NMOS FET switch turns on and the SUB display is

turned off. If both VEn1 and VEn2 are ≤0.3V the LM3503 will shutdown. If VOUT2 is not used, En2 must be floating

or grounded and En1 used to enable the device.

En1 (Bump A2): Enable pin for the internal PMOS FET switch (Figure 3: P1) during device operation. When

VEn1 is ≤0.3V, the internal PMOS FET switch turns on and the MAIN display is turned off. When VEn1 is ≥1.4V,

the internal PMOS FET switch turns off and the MAIN display is turned on. If both VEn1 and VEn2 are ≤0.3V the

LM3503 will shutdown. The En1 pin has an internal pull down circuit, thus the internal PMOS FET switch is

normally in the on state of operation with the MAIN display turned off. If VOUT2 is not used, En2 must be grounded

and En1 use to enable the device.

These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam

during storage or handling to prevent electrostatic damage to the MOS gates.

Absolute Maximum Ratings(1)(2)

VIN Pin −0.3V to +5.5V

Sw Pin −0.3V to +48V

Fb Pin −0.3V to +5.5V

Cntrl Pin −0.3V to +5.5V

VOUT1Pin −0.3V to +48V

VOUT2 Pin −0.3V to VOUT1

En1 −0.3V to +5.5V

En2 −0.3V to +5.5V

Continuous Power Dissipation Internally Limited

Maximum Junction Temperature (TJ-MAX) +150°C

Storage Temperature Range −65°C to +150°C

ESD Rating(3) Human Body Model 2 kV

Machine Model 200V

(1) Absolute maximum ratings indicate limits beyond which damage to the device may occur. Electrical characteristic specifications do not

apply when operating the device outside of its rated operating conditions.

(2) If Military/Aerospace specified devices are required, please contact the TI Sales Office/ Distributors for availability and specifications.

(3) The human body model is a 100 pF capacitor discharged through a 1.5 kΩresistor into each pin. The machine model is a 200 pF

capacitor discharged directly into each pin.

Operating Conditions(1)(2)

Junction Temperature (TJ) Range −40°C to +125°C

Ambient Temperature (TA) Range −40°C to +85°C

Supply Voltage, VIN Pin 2.5V to 5.5V

En1 and En2 Pins 0V to 5.5V

Cntrl Pin 0V to 3.5V

(1) Absolute maximum ratings indicate limits beyond which damage to the device may occur. Electrical characteristic specifications do not

apply when operating the device outside of its rated operating conditions.

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

Product Folder Links: LM3503

LM3503

SNVS329E –JULY 2005–REVISED MAY 2013

www.ti.com

Thermal Properties(3)

Junction-to-Ambient Thermal Resistance (θJA)

DSBGA Package 65°C/W

WQFN Package 49°C/W

(3) The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(MAX), the junction-to-ambient thermal

resistance, θJA, and the ambient temperature, TA. See Thermal Properties for the thermal resistance. The maximum allowable power

dissipation at any ambient temperature is calculated using: PD(MAX) = (TJ(MAX)–TA)/ θJA. Exceeding the maximum allowable power

dissipation will cause excessive die temperature. For more information on this topic, please refer to Application Note 1187(An1187):

Leadless Leadframe Package (LLP) and Application Note 1112(AN1112) for DSBGA chip scale package.

Electrical Characteristics(1)(2)

Limits in standard typeface are for TJ= +25°C. Limits in bold typeface apply over the full operating junction temperature

range (−40°C ≤TJ≤+125°C). Unless otherwise specified,VIN = 2.5V.

Symbol Parameter Conditions Min Typ Max Units

VIN Input Voltage 2.5 5.5 V

IQNon-Switching Cntrl = 1.6V 0.5 1mA

Switching Fb = 0V, Sw Is Floating 1.9 3mA

Shutdown En1 = En2 = 0V 0.1 3µA

VFb Feedback Voltage Cntrl = 3.5V 0.5 0.55 0.6 V

ICL NMOS Power Switch 16, Fb = 0V 250 400 650

Current Limit 25, Fb = 0V 400 600 800 mA

35, Fb = 0V 450 750 1050

44,FB = 0V 450 750 1050

IFb Feedback Pin Output Fb = 0.25V, Cntrl = 1.6V 64 500 nA

Bias Current

FSSwitching Frequency 0.8 11.2 MHz

RDS(ON) NMOS Power Switch ON ISw = 500 mA(3)

Resistance 0.55 1.1 Ω

(Figure 3: N1)

RPDS(ON) PMOS ON Resistance IPMOS = 20 mA, En1 = 0V, En2 = 1.5V

Of VOUT1/VOUT2 Switch 5 10 Ω

(Figure 3: P1)

RNDS(ON) NMOS ON Resistance INMOS = 20 mA, En1 = 1.5V, En2 = 0V

Of VOUT2/Fb Switch 2.5 5Ω

(Figure 3: N2)

DMAX Maximum Duty Cycle Fb = 0V 90 95 %

ISw Sw Pin Leakage Sw = 42V, En1 = En2 =0V 0.01 5µA

Current(4)

IVOUT1(OFF) VOUT1 Pin Leakage VOUT1 = 14V, En1 = En2 = 0V (16) 0.1 3

Current(4) VOUT1 = 23V, En1 = En2 = 0V (25) 0.1 3µA

VOUT1 = 32V, En1 = En2 = 0V (35) 0.1 3

VOUT1 = 42V, En1 = En2 = 0V (44) 0.1 3

IVOUT1(ON) VOUT1 Pin Bias VOUT1 = 14V, En1 = En1 = 1.5V (16) 40 80

Current(4) VOUT1 = 23V, En1 = En2 = 1.5V (25) 50 100 µA

VOUT1 = 32V, En1 = En2 = 1.5V (35) 50 100

VOUT1 = 42V, En1 = En2 = 1.5V (44) 85 140

IVOUT2 VOUT2Pin Leakage Fb = En1 = En2 = 0V, VOUT2 = VOUT1 = 42V 0.1 3µA

Current(4)

UVP Under-Voltage On Threshold 2.4 2.5 V

Protection Off Threshold 2.2 2.3

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

(2) Min and Max limits are ensured by design, test, or statistical analysis. Typical numbers are not specified, but do represent the most

likely norm.

(3) NMOS Power On Resistance measured at ISW= 250mA for sixteen voltage version.

(4) Current flows into the pin.

Product Folder Links: LM3503

LM3503

www.ti.com

SNVS329E –JULY 2005–REVISED MAY 2013

Electrical Characteristics(1)(2) (continued)

Limits in standard typeface are for TJ= +25°C. Limits in bold typeface apply over the full operating junction temperature

range (−40°C ≤TJ≤+125°C). Unless otherwise specified,VIN = 2.5V.

Symbol Parameter Conditions Min Typ Max Units

OVP Over-Voltage On Threshold (16) 14.5 15.5 16.5

Protection(5) Off Threshold (16) 14.0 15 16.0

On Threshold (25) 22.5 24 25.5

F Off Threshold (25) 21.5 23 24.5 V

On Threshold (35) 32.0 34 35.0

Off Threshold (35) 31.0 33 34.0

On Threshold (44) 40.5 42 43.5

Off Threshold (44) 39.0 41 42.0

VEn1 PMOS FET Switch and Off Threshold 0.8 0.3

Device Enabling V

On Threshold 1.4 0.8

Threshold (Figure 3: P1)

VEn2 NMOS FET Switch and Off Threshold 0.8 0.3

Device Enabling V

On Threshold 1.4 0.8

Threshold (Figure 3: N2)

VCntrl VCntrl Range VIN = 3.6V 0.2 3.5 V

IEn1 En1 Pin Bias Current(6) En1 = 2.5V 7 14 µA

En1 = 0V 0.1

IEn2 En2 Pin Bias Current(6) En2 = 2.5V 7 14 µA

En2 = 0V 0.1

ICNTRL Cntrl Pin Bias Current(6) Cntrl = 2.5V 8 14 µA

(5) The on threshold indicates that the LM3503 is no longer switching or regulating LED current, while the off threshold indicates normal

operation.

(6) Current flows into the pin.

Product Folder Links: LM3503

Driver Logic

Oscillator

Current Sense

Thermal Shutdown

Duty Limit

Reference

Duty Limit

Comparator

UVP

Comparator

OVP

Comparator

PWM

Comparator

Light Load

Comparator

Light Load

Reference

VIN Sw

VOUT1

VOUT2

En2En1PGND

Cntrl

AGND

Error

Amplifier

UVP

Reference OVP

Reference

Current Limit

Soft Start

15,16 1210

2,313

FET Logic

LM3503

SNVS329E –JULY 2005–REVISED MAY 2013

www.ti.com

Block Diagram

Figure 3. Block Diagram

Detailed Description of Operation

The LM3503 utilizes an asynchronous current mode pulse-width-modulation (PWM) control scheme to regulate

the feedback voltage over specified load conditions. The DC/DC converter behaves as a controlled current

source for white LED applications. The operation can best be understood by referring to the block diagram in

Figure 3 for the following operational explanation. At the start of each cycle, the oscillator sets the driver logic

and turns on the internal NMOS power device, N1, conducting current through the inductor and reverse biasing

the external diode. The white LED current is supplied by the output capacitor when the internal NMOS power

device, N1, is turned on. The sum of the error amplifier’s output voltage and an internal voltage ramp are

compared with the sensed power NMOS, N1, switch voltage. Once these voltages are equal, the PWM

comparator will then reset the driver logic, thus turning off the internal NMOS power device, N1, and forward

biasing the external diode. The inductor current then flows through the diode to the white LED load and output

capacitor. The inductor current recharges the output capacitor and supplies the current for the white LED load.

The oscillator then sets the driver logic again repeating the process. The output voltage of the error amplifier

controls the current through the inductor. This voltage will increase for larger loads and decrease for smaller

loads limiting the peak current in the inductor and minimizing EMI radiation. The duty limit comparator is always

operational, it prevents the internal NMOS power switch, N1, from being on for more than one oscillator cycle

and conducting large amounts of current. The light load comparator allows the LM3503 to properly regulate

light/small white LED load currents, where regulation becomes difficult for the LM3503’s primary control loop.

Under light load conditions, the LM3503 will enter into a pulse skipping pulse-frequency-mode (PFM) of operation

where the operational frequency will vary with the load. As a result of PFM mode operation, the output voltage

ripple magnitude will significantly increase.

Product Folder Links: LM3503

-30

-20

-10 0102030405060708090

100

110

120

130

TEMPERATURE (oC)

0.93

0.94

0.95

0.96

0.97

0.98

0.99

1.00

1.01

1.02

1.03

FREQUENCY (MHz)

-40

VIN = 2.5V

3.0 3.5 4.0 4.5 5.0 5.5

INPUT VOLTAGE (V)

0.400

0.440

0.480

0.520

0.560

0.600

NON-SWITCHING IQ (mA)

2.5

-40oC

0.420

0.460

0.500

0.540

0.580

125oC

25oC

En1 En2

0.3V 0.3V

Result (See Figure 1 and Figure 2)

1.4V 0.3V

0.3V 1.4V

1.4V 1.4V

[P1ÆOFF N2ÆOFF N1ÆOFF] or [MAINÆOFF SUBÆOFF N1ÆOFF]

[P1ÆOFF N2ÆON N1ÆSwitching] or [MAINÆON SUBÆOFF N1ÆSwitching]

[P1ÆON N2ÆOFF N1ÆSwitching] or [MAINÆOFF SUBÆON N1ÆSwitching]

[P1ÆOFF N2ÆOFF N1ÆSwitching] or [MAINÆON SUBÆON N1ÆSwitching]

Shutdown

LM3503

www.ti.com

SNVS329E –JULY 2005–REVISED MAY 2013

The LM3503 has two control pins, En1 and En2, used for selecting which segment of a single white LED string

network is active for dual display applications. En1 controls the main display (MAIN) segment of the single string

white LED network between pins VOUT1 and VOUT2. En2 controls the sub display (SUB) segment of the single

string white LED network between the VOUT2 and Fb. If both VEn1 and VEn2 are ≤0.3V, the LM3503 will shutdown,

for further description of the En1 and En2 operation, see Figure 33. During shutdown the output capacitor

discharges through the string of white LEDs and feedback resistor to ground. The LED current can be

dynamically controlled by a DC voltage on the Cntrl pin. When VCntrl = 0V the white LED current may not be

equal to zero because of offsets within the LM3503 internal circuitry. To ensure zero white LED current the

LM3503 must be in shutdown mode operation.

The LM3503 has dedicated protection circuitry active during normal operation to protect the integrated circuit (IC)

and external components. Soft start circuitry is present in the LM3503 to allow for slowly increasing the current

limit to its steady-state value to prevent undesired high inrush current during start up. Thermal shutdown circuitry

turns off the internal NMOS power device, N1, when the internal semiconductor junction temperature reaches

excessive levels. The LM3503 has a under-voltage protection (UVP) comparator that disables the internal NMOS

power device when battery voltages are too low, thus preventing an on state where the internal NMOS power

device conducts large amounts of current. The over-voltage protection (OVP) comparator prevents the output

voltage from increasing beyond the protection limit when the white LED string network is removed or if there is a

white LED failure. OVP allows for the use of low profile ceramic capacitors at the output. The current through the

internal NMOS power device, N1, is monitored to prevent peak inductor currents from damaging the IC. If during

a cycle (cycle=1/switching frequency) the peak inductor current exceeds the current limit for the LM3503, the

internal NMOS power device will be turned off for the remaining duration of that cycle.

Figure 4. Operational Characteristics Table

Typical Performance Characteristics

(See Typical Application Circuit : L=DO1608C-223 and D=B150-13. Efficiency: η= POUT/ PIN = [(VOUT – VFb ) * IOUT] / [VIN * IIN].

TA= +25°C, unless otherwise stated.)

IQ(Non-Switching) Switching Frequency

vs vs

VIN Temperature

Figure 5. Figure 6.

Product Folder Links: LM3503

0 4 8 12 16 20

EFFICIENCY (%)

LED CURRENT (mA)

VIN = 2.7V

2 6 10 14 18

VIN = 5.5V

VIN = 3.3V

VIN = 4.2V

VIN = 3V

4 8 12 16 20

LED CURRENT (mA)

100

EFFICIENCY (%)

VIN = 4.2V

6 10 14 182

VIN = 5.5V

VIN = 3.3V

VIN = 3V

VIN = 2.7V

0 4 8 12 16 20

EFFICIENCY (%)

LED CURRENT (mA)

VIN = 2.7V

2 6 10 14 18

VIN = 5.5V

VIN = 3.3V

VIN = 4.2V

VIN = 3V

2 4 6 8 10 12 14 16 18 20

LED CURRENT (mA)

EFFICIENCY (%)

VIN = 3V

VIN = 5.5V

VIN = 2.7V

VIN = 4.2V

VIN = 3.3V

-30

-20

-10 0102030405060708090

100

110

120

130

TEMPERATURE (oC)

1.75

1.95

SWITCHING IQ (mA)

-40

1.80

1.85

1.90 VIN = 2.5V

3.0 3.5 4.0 4.5 5.0 5.5

INPUT VOLTAGE (V)

1.50

2.00

2.50

3.00

3.50

4.00

SWITCHING IQ (mA)

2.5

25oC125oC

-40oC

LM3503

SNVS329E –JULY 2005–REVISED MAY 2013

www.ti.com

Typical Performance Characteristics (continued)

(See Typical Application Circuit : L=DO1608C-223 and D=B150-13. Efficiency: η= POUT/ PIN = [(VOUT – VFb ) * IOUT] / [VIN * IIN].

TA= +25°C, unless otherwise stated.)

IQ(Switching) IQ(Switching)

vs vs

VIN Temperature

Figure 7. Figure 8.

10 LED Efficiency 8 LED Efficiency

vs vs

LED Current LED Current

Figure 9. Figure 10.

6 LED Efficiency 4 LED Efficiency

vs vs

LED Current LED Current

Figure 11. Figure 12.

Product Folder Links: LM3503

2.5 3.0 3.5 4.0 4.5 5.0 5.5

INPUT VOLTAGE (V)

300

400

500

600

700

800

900

1000

POWER NMOS RDS(ON) (m:)

125oC

INMOS = 400 mA

25oC

-40oC

8 16 24 32 40 48

VOUT1 PIN VOLTAGE (V)

100

120

140

160

VOUT1 PIN BIAS CURRENT (PA)

125oC

25oC

-40oC

EN2 PIN VOLTAGE (V)

EN2 PIN CURRENT (PA)

0.0 2.0 4.01.0 3.0 5.0

-40oC

125oC

25oC

EN1 PIN VOLTAGE (V)

EN1 PIN CURRENT (PA)

0.0 1.0 2.0 3.0 4.0 5.0

125oC

-40oC

25oC

-30

-20

-10 0102030405060708090

100

110

120

130

TEMPERATURE (oC)

MAX DUTY CYCLE (%)

-40

97 VIN = 2.5

0.0 0.5 1.0 1.5 2.0 2.5 3.0

CNTRL PIN VOLTAGE (V)

CNTRL PIN CURRENT (PA)

-40oC

125oC

25oC

LM3503

www.ti.com

SNVS329E –JULY 2005–REVISED MAY 2013

Typical Performance Characteristics (continued)

(See Typical Application Circuit : L=DO1608C-223 and D=B150-13. Efficiency: η= POUT/ PIN = [(VOUT – VFb ) * IOUT] / [VIN * IIN].

TA= +25°C, unless otherwise stated.)

Cntrl Pin Current Maximum Duty Cycle

vs vs

Cntrl Pin Voltage Temperature

Figure 13. Figure 14.

En1 Pin Current En2 Pin Current

vs vs

En1 Pin Voltage En2 Pin Voltage

Figure 15. Figure 16.

VOUT1 Pin Current Power NMOS RDS(ON) (Figure 3: N1)

vs vs

VOUT1Pin Voltage VIN

Figure 17. Figure 18.

Product Folder Links: LM3503

-25 -10 5 20 35 50 65 80

TEMPERATURE (oC)

420

440

460

480

500

520

540

560

580

600

620

-25 CURRENT LIMIT (mA)

-40

VIN = 5.5V

VIN = 7.0V

VIN = 2.5V

3.0 3.5 4.0 4.5 5.0 5.5

INPUT VOLTAGE (V)

320

340

360

380

400

420

440

460

480

-16 CURRENT LIMIT (mA)

2.5

T = -40oC

T = 25oC

T = 85oC

0.3 0.5 0.7 0.9 1.1 1.3 1.5

CNTRL VOLTAGE (V)

0.00

0.04

0.08

0.12

0.16

0.20

0.24

0.28

FEEDBACK VOLTAGE (V)

VIN = 2.7V

VIN = 5.5V

-40 80

TEMPERATURE (oC)

-16 CURRENT LIMIT (mA)

-25 -10 5 20 35 50 65

320

340

360

380

400

420

440

VIN = 5.5V

VIN = 7.0V

VIN = 2.5V

2.0 12.0 22.0 32.0 42.0

PMOS SWITCH RDS(ON) (:)

VOUT1 PIN VOLTAGE (V)

125oC

IPMOS = 20 mA

25oC

-40oC

2.5 3.0 3.5 4.0 4.5 5.0 5.5

INPUT VOLTAGE (V)

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

NMOS SWITCH RDS(ON) (:)

-40oC

INMOS = 20 mA

125oC

25oC

LM3503

SNVS329E –JULY 2005–REVISED MAY 2013

www.ti.com

Typical Performance Characteristics (continued)

(See Typical Application Circuit : L=DO1608C-223 and D=B150-13. Efficiency: η= POUT/ PIN = [(VOUT – VFb ) * IOUT] / [VIN * IIN].

TA= +25°C, unless otherwise stated.)

NMOS RDS(ON) (Figure 3: N2) PMOS RDS(ON) (Figure 3: P1)

vs vs

VIN VIN

Figure 19. Figure 20.

Feedback Voltage Current Limit (LM3503-16)

vs vs

Cntrl Pin Voltage Temperature

Figure 21. Figure 22.

Current Limit (LM3503-16) Current Limit (LM3503-25)

vs vs

VIN Temperature

Figure 23. Figure 24.

Product Folder Links: LM3503

-40

TEMPERATURE (oC)

0.249

0.250

0.251

0.252

0.253

0.254

0.255

0.256

0.257

FEEDBACK VOLTAGE (V)

-30-20-10 010 20 30 40 50 60 70 80

VIN = 5.5V

CNTRL = 1.6V

VIN = 2.7V

-40

TEMPERATURE (oC)

0.119

0.120

0.121

0.122

0.123

0.124

0.125

0.126

0.127

FEEDBACK VOLTAGE (V)

-30-20-10 010 20 30 40 50 60 70 80

VIN = 2.7V

CNTRL = 0.8V

VIN = 5.5V

5.0

INPUT VOLTAGE (V)

690

700

710

720

730

740

750

760

770

780

CURRENT LIMIT (mA)

5.54.54.03.53.02.5

85oC

-40oC

25oC

5.0

INPUT VOLTAGE (V)

440

460

480

500

520

540

560

580

600

620

-25 CURRENT LIMIT (mA)

5.54.54.03.53.02.5

T = -40oC

T = 25oC

T = 85oC

-40 80

TEMPERATURE (oC)

-35/44 CURRENT LIMIT (mA)

-25 -10 5 20 35 50 65

VIN = 7.0V

690

700

710

720

730

740

750

760

780

770

VIN = 2.5V

LM3503

www.ti.com

SNVS329E –JULY 2005–REVISED MAY 2013

Typical Performance Characteristics (continued)

(See Typical Application Circuit : L=DO1608C-223 and D=B150-13. Efficiency: η= POUT/ PIN = [(VOUT – VFb ) * IOUT] / [VIN * IIN].

TA= +25°C, unless otherwise stated.)

Current Limit (LM3503-25) Current Limit (LM3503-35/44)

vs vs

VIN Temperature

Figure 25. Figure 26.

Current Limit (LM3503-35/44) Feedback Voltage (VCntrl = 0.8V)

vs vs

VIN Temp

Figure 27. Figure 28.

Feedback Voltage (VCntrl = 1.6V)

Temp VIN = 3.6V at 15mA & 4 Leds

Figure 29. Figure 30.

Product Folder Links: LM3503

LED CURRENT (mA)

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

10 20 30 40 50 60 70

80 90

DUTY CYCLE (%)

50 kHz

10 kHz

1 kHz 500 Hz

200 Hz

LM3503

SNVS329E –JULY 2005–REVISED MAY 2013

www.ti.com

Typical Performance Characteristics (continued)

(See Typical Application Circuit : L=DO1608C-223 and D=B150-13. Efficiency: η= POUT/ PIN = [(VOUT – VFb ) * IOUT] / [VIN * IIN].

TA= +25°C, unless otherwise stated.) Dimming Duty Cycle vs LED Current

VIN = 3.6V at 15mA & 2 Leds VIN=3.6V, 2LEDs on Main & Sub Display

Figure 31. Figure 32.

Product Folder Links: LM3503

FPWM > 10 x FRC

FRC = 1

2 x S x R x C

YLM3503

VIN Sw

En1

En2 Fb

Cntrl

AGND PGND

VOUT1

VOUT2

PWM Signal

ILED =R1

VFb

VFB = (0.156) x (VCntrl)

LM3503

www.ti.com

SNVS329E –JULY 2005–REVISED MAY 2013

APPLICATION INFORMATION

WHITE LED CURRENT SETTING

The white LED current is controlled by a DC voltage at the Cntrl pin.

The relationship between the Cntrl pin voltage and Fb pin voltage can be computed with the following:

• VCntrl: Cntrl Pin Voltage. Voltage Range: 0.2V ≤VCntrl ≤3.5V.

• VFb: Feedback Pin Voltage. (1)

LED CURRENT

The LED current is set using the following equation:

(2)

To determine the maximum output current capability of the device, it is best to estimate using equations on page

16 and the minimum peak current limit of the device (see electrical table). Note the current capability will be

higher with less LEDs in the application.

WHITE LED DIMMING

Figure 33. If VOUT2 is not used, En2 must be grounded

Aside from varying the DC voltage at the Cntrl pin, white LED dimming can be accomplished through the RC

filtering of a PWM signal. The PWM signal frequency should be at least a decade greater than the RC filter

bandwidth. WHITE LED DIMMING is how the LM3503 should be wired for PWM filtered white LED dimming

functionality. When using PWM dimming, it is recommended to add 1-2ms delay between the Cntrl signal and the

main Enable sginal (En1) to allow time for the output to discharge. This will prevent potential flickering especially

if the Sub display is compose of 2 LEDs or less.

The equations below are guidelines for choosing the correct RC filter values in relation to the PWM signal

frequency.

Equation:

(3)

Equation: (4)

Product Folder Links: LM3503

IL (avg)

Time

Inductor Current

'iL

tON = DTS

(Vin - Vout)/L

Vin/L

LM3503

SNVS329E –JULY 2005–REVISED MAY 2013

www.ti.com

FRC:RC Filter Bandwidth Cutoff Frequency.

FPWM:PWM Signal Frequency.

R: Chosen Filter Resistor.

C: Chosen Filter Capacitor.

For example, using the above equations to determine the proper RC values. Assume the following condition:VIN=

3.6V, C=0.01µF and FPWM = 500Hz, then FRC= 50Hz by relation to equation 2. By rearranging equation 1 to solve

for R; R = 318.5K ohms (standard value, R = 316K).

PWM Dimming Duty Cycle vs. LED Current

The results are based on the 2LEDs on Main display and 2LEDs on Sub display

Duty 200Hz 500Hz 1KHz 10KHz 50KHz 100kHz

(%) R = 787k ohms R =316k ohms R = 158kohms R=16.2k ohms R=3.16k ohms R=1.62k ohms

10 0.78mA 1.59mA 2.23mA 3.42mA 3.58mA 3.61mA

20 1.85mA 3.46mA 4.78mA 7.09mA 7.41mA 7.48mA

30 2.88mA 5.35mA 7.33mA 10.77mA 11.25mA 11.34mA

40 3.96mA 7.24mA 9.88mA 14.48mA 15.12mA 15.24mA

50 5.05mA 9.12mA 12.45mA 19.1mA 19.06mA 19.16mA

60 6.08mA 11.03mA 15.03mA 21.86mA 22.98mA 23.10mA

70 7.13mA 12.94mA 17.61mA 25.71mA 26.9mA 27.05mA

80 8.17mA 14.83mA 20.20mA 29.53mA 30.83mA 31.00mA

90 9.24mA 16.73mA 22.79mA 33.32mA 34.78mA 35.00mA

Figure 34. Inductor Current Waveform

CONTINUOUS AND DISCONTINUOUS MODES OF OPERATION

Since the LM3503 is a constant frequency pulse-width-modulated step-up regulator, care must be taken to make

sure the maximum duty cycle specification is not violated. The duty cycle equation depends on which mode of

operation the LM3503 is in. The two operational modes of the LM3503 are continuous conduction mode (CCM)

and discontinuous conduction mode (DCM). Continuous conduction mode refers to the mode of operation where

during the switching cycle, the inductor current never goes to and stays at zero for any significant amount of time

during the switching cycle. Discontinuous conduction mode refers to the mode of operation where during the

switching cycle, the inductor current goes to and stays at zero for a significant amount of time during the

switching cycle. Figure 34 illustrates the threshold between CCM and DCM operation. In Figure 34 the inductor

current is right on the CCM/DCM operational threshold. Using this as a reference, a factor can be introduced to

calculate when a particular application is in CCM or DCM operation. R is a CCM/DCM factor we can use to

compute which mode of operation a particular application is in. If R is ≥1, then the application is operating in

CCM. Conversely, if R is < 1, the application is operating in DCM. The R factor inequalities are a result of the

components that make up the R factor. From Figure 34, the R factor is equal to the average inductor current,

IL(avg), divided by half the inductor ripple current, ΔiL. Using Figure 34, the following equation can be used to

compute R factor:

Product Folder Links: LM3503

D = [2 * IOUT * L * (VOUT - VIN) * Fs]

[(VIN)2 * Eff]

tON

D =

D = [VOUT]

[VOUT - VIN]

tON

D =

R = [2 * IOUT * L * Fs * (VOUT)2]

[(VIN)2 * Eff * (VOUT - VIN)]

'iL = [VIN * D]

[L * Fs]

IL (avg) = [IOUT]

[(1-D) * Eff]

R = 'iL

2 * IL (avg)

LM3503

www.ti.com

SNVS329E –JULY 2005–REVISED MAY 2013

(5)

(6)

(7)

(8)

VIN:Input Voltage.

VOUT:Output Voltage.

Eff: Efficiency of the LM3503.

Fs: Switching Frequency.

IOUT:White LED Current/Load Current.

L: Inductance Magnitude/Inductor Value.

D: Duty Cycle for CCM operation.

ΔiL:Inductor Ripple Current.

IL(avg): Average Inductor Current.

For CCM operation, the duty cycle can be computed with:

(9)

(10)

D: Duty Cycle for CCM Operation.

VOUT:Output Voltage.

VIN :Input Voltage.

For DCM operation, the duty cycle can be computed with:

(11)

(12)

D: Duty Cycle for DCM Operation.

VOUT:Output Voltage.

VIN :Input Voltage.

IOUT:White LED Current/Load Current.

Fs: Switching Frequency.

L: Inductor Value/Inductance Magnitude.

INDUCTOR SELECTION

In order to maintain inductance, an inductor used with the LM3503 should have a saturation current rating larger

than the peak inductor current of the particular application. Inductors with low DCR values contribute decreased

power losses and increased efficiency. The peak inductor current can be computed for both modes of operation:

CCM and DCM.

The cycle-by-cycle peak inductor current for CCM operation can be computed with:

Product Folder Links: LM3503

[VIN * RDS(ON) * ((D/'¶) - 1)]

[1.562 * Fs]

L >

[VIN * D]

[L * Fs]

IPeak

[IOUT]

[(1 - D) * Eff] +[VIN * D]

[2 * L * Fs]

IPeak

IPeak IL (avg) +

'iL

LM3503

SNVS329E –JULY 2005–REVISED MAY 2013

www.ti.com

(13)

(14)

VIN:Input Voltage.

Eff: Efficiency of the LM3503.

Fs: Switching Frequency.

IOUT:White LED Current/Load Current.

L: Inductance Magnitude/Inductor Value.

D: Duty Cycle for CCM Operation.

IPEAK:Peak Inductor Current.

ΔiL:Inductor Ripple Current.

IL(avg): Average Inductor Current.

The cycle-by-cycle peak inductor current for DCM operation can be computed with:

(15)

VIN:Input Voltage.

Fs: Switching Frequency.

L: Inductance Magnitude/Inductor Value.

D: Duty Cycle for DCM Operation.

IPEAK:Peak Inductor Current.

The minimum inductance magnitude/inductor value for the LM3503 can be calculated using the following, which

is only valid when the duty cycle is > 0.5:

(16)

D: Duty Cycle.

D’: 1-D.

RDS(ON):NMOS Power Switch ON Resistance.

Fs: Switching Frequency.

VIN:Input Voltage.

L: Inductance Magnitude/Inductor Value.

This equation gives the value required to prevent subharmonic oscillations. The result of this equation and the

inductor ripple currents should be accounted for when choosing an inductor value.

Some recommended Inductor manufactures included but are not limited to:

DO1608C-223

Coilcraft www.coilcraft.com

DT1608C-223

Product Folder Links: LM3503

LM3503

www.ti.com

SNVS329E –JULY 2005–REVISED MAY 2013

CAPACITOR SELECTION

Multilayer ceramic capacitors are the best choice for use with the LM3503. Multilayer ceramic capacitors have

the lowest equivalent series resistance (ESR). Applied voltage or DC bias, temperature, dielectric material type

(X7R, X5R, Y5V, etc), and manufacturer component tolerance have an affect on the true or effective capacitance

of a ceramic capacitor. Be aware of how your application will affect a particular ceramic capacitor by analyzing

the aforementioned factors of your application. Before selecting a capacitor always consult the capacitor

manufacturer’s data curves to verify the effective or true capacitance of the capacitor in your application.

INPUT CAPACITOR SELECTION

The input capacitor serves as an energy reservoir for the inductor. In addition to acting as an energy reservoir for

the inductor the input capacitor is necessary for the reduction in input voltage ripple and noise experienced by

the LM3503. The reduction in input voltage ripple and noise helps ensure the LM3503’s proper operation, and

reduces the effect of the LM3503 on other devices sharing the same supply voltage. To ensure low input voltage

ripple, the input capacitor must have an extremely low ESR. As a result of the low input voltage ripple

requirement multilayer ceramic capacitors are the best choice. A minimum capacitance of 2.0 µF is required for

normal operation, so consult the capacitor manufacturer’s data curves to verify whether the minimum

capacitance requirement is going to be achieved for a particular application.

OUTPUT CAPACITOR SELECTION

The output capacitor serves as an energy reservoir for the white LED load when the internal power FET switch

(Figure 3: N1) is on or conducting current. The requirements for the output capacitor must include worst case

operation such as when the load opens up and the LM3503 operates in over-voltage protection (OVP) mode

operation. A minimum capacitance of 0.5 µF is required to ensure normal operation. Consult the capacitor

manufacturer’s data curves to verify whether the minimum capacitance requirement is going to be achieved for a

particular application.

Some recommended capacitor manufacturers included but are not limited to:

Taiyo-Yuden GMK212BJ105MD (0805/35V) www.t-yuden.com

muRata GRM40-035X7R105K (0805/50V) www.murata.com

TDK C3216X7R1H105KT (1206/50V) www.tdktca.com

C3216X7R1C475K (1206/16V)

AVX 08053D105MAT (0805/25V) www.avxcorp.com

08056D475KAT (0805/6.3V)

1206ZD475MAT (1206/10V)

DIODE SELECTION

To maintain high efficiency it is recommended that the average current rating (IFor IO) of the selected diode

should be larger than the peak inductor current (ILpeak). At the minimum the average current rating of the diode

should be larger than the maximum LED current. To maintain diode integrity the peak repetitive forward current

(IFRM) must be greater than or equal to the peak inductor current (ILpeak). Diodes with low forward voltage ratings

(VF) and low junction capacitance magnitudes (CJor CTor CD) are conducive to high efficiency. The chosen

diode must have a reverse breakdown voltage rating (VRand/or VRRM) that is larger than the output voltage

(VOUT). No matter what type of diode is chosen, Schottky or not, certain selection criteria must be followed:

1. VRand VRRM > VOUT

2. IFor IO≥ILOAD or IOUT

3. IFRM ≥ILpeak

Some recommended diode manufacturers included but are not limited to:

Vishay SS12(1A/20V) www.vishay.com

SS14(1A/40V)

SS16(1A/60V)

Product Folder Links: LM3503

LM3503

SNVS329E –JULY 2005–REVISED MAY 2013

www.ti.com

On Semiconductor MBRM120E (1A/20V) www.onsemi.com

MBRS1540T3 (1.5A/40V)

MBR240LT (2A/40V)

Central Semiconductor CMSH1-40M (1A/40V) www.centralsemi.com

SHUTDOWN AND START-UP

On startup, the LM3503 contains special circuitry that limits the peak inductor current which prevents large

current spikes from loading the battery or power supply. The LM3503 is shutdown when both En1 and En2

signals are less than 0.3V. During shutdown the output voltage is a diode drop below the supply voltage. When

shutdown, the softstart is reset to prevent inrush current at the next startup.

THERMAL SHUTDOWN

The LM3503 stops regulating when the internal semiconductor junction temperature reaches approximately

140°C. The internal thermal shutdown has approximately 20°C of hysteresis which results in the LM3503 turning

back on when the internal semiconductor junction temperature reaches 120°C. When the thermal shutdown

temperature is reached, the softstart is reset to prevent inrush current when the die temperature cools.

UNDER VOLTAGE PROTECTION

The LM3503 contains protection circuitry to prevent operation for low input supply voltages. When Vin drops

below 2.3V, typically, the LM3503 will no longer regulate. In this mode, the output voltage will be one diode drop

below Vin and the softstart will be reset. When Vin increases above 2.4V, typically, the device will begin

regulating again.

OVER VOLTAGE PROTECTION

The LM3503 contains dedicated ciruitry for monitoring the output voltage. In the event that the LED network is

disconnected from the LM3503, the output voltage will increase and be limited to 15.5V(typ.) for the 16V version,

24V(typ.) for the 25V version, 34V(typ.) for 35V version and 42V(typ.) for the 44V version. (see electrical table for

more details). In the event that the network is reconnected regulation will resume at the appropriate output

voltage.

LAYOUT CONSIDERATIONS

All components, except for the white LEDs, must be placed as close as possible to the LM3503. The die attach

pad (DAP) must be soldered to the ground plane.

The input bypass capacitor CIN, as shown in the Typical Application Circuit, must be placed close to the IC and

connect between the VIN and Pgnd pins. This will reduce copper trace resistance which effects input voltage

ripple of the IC. For additional input voltage filtering, a 100 nF bypass capacitor can be placed in parallel with CIN

to shunt any high frequency noise to ground. The output capacitor, COUT, must be placed close to the IC and be

connected between the VOUT1 and Pgnd pins. Any copper trace connections for the COUT capacitor can increase

the series resistance, which directly effects output voltage ripple and efficiency. The current setting resistor, R1,

should be kept close to the Fb pin to minimize copper trace connections that can inject noise into the system.

The ground connection for the current setting resistor network should connect directly to the Pgnd pin. The Agnd

pin should be tied directly to the Pgnd pin. Trace connections made to the inductor should be minimized to

reduce power dissipation and increase overall efficiency while reducing EMI radiation. For more details regarding

layout guidelines for switching regulators, refer to Applications Note AN-1149.

Product Folder Links: LM3503

LM3503

www.ti.com

SNVS329E –JULY 2005–REVISED MAY 2013

REVISION HISTORY

Changes from Revision D (May 2013) to Revision E Page

• Changed layout of National Data Sheet to TI format .......................................................................................................... 18

Product Folder Links: LM3503

PACKAGE OPTION ADDENDUM

www.ti.com 16-Oct-2015

Addendum-Page 1

PACKAGING INFORMATION

Orderable Device Status

(1)

Package Type Package

Drawing Pins Package

Qty Eco Plan

(2)

Lead/Ball Finish

(6)

MSL Peak Temp

(3)

Op Temp (°C) Device Marking

(4/5)

Samples

LM3503ITL-25/NOPB LIFEBUY DSBGA YPA 10 250 Green (RoHS

& no Sb/Br) SNAGCU Level-1-260C-UNLIM -40 to 85 SBJB

LM3503ITL-35/NOPB LIFEBUY DSBGA YPA 10 250 Green (RoHS

& no Sb/Br) SNAGCU Level-1-260C-UNLIM -40 to 85 SBKB

LM3503ITL-44/NOPB LIFEBUY DSBGA YPA 10 250 Green (RoHS

& no Sb/Br) SNAGCU Level-1-260C-UNLIM -40 to 85 SDNB

LM3503SQ-16/NOPB LIFEBUY WQFN RGH 16 1000 Green (RoHS

& no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 L00045B

LM3503SQ-25/NOPB LIFEBUY WQFN RGH 16 1000 Green (RoHS

& no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 L00046B

LM3503SQ-35 LIFEBUY WQFN RGH 16 1000 TBD Call TI Call TI -40 to 85 L00047B

LM3503SQ-35/NOPB LIFEBUY WQFN RGH 16 1000 Green (RoHS

& no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 L00047B

(1) The marketing status values are defined as follows:

ACTIVE: Product device recommended for new designs.

LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.

NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.

PREVIEW: Device has been announced but is not in production. Samples may or may not be available.

OBSOLETE: TI has discontinued the production of the device.

(2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability

information and additional product content details.

TBD: The Pb-Free/Green conversion plan has not been defined.

Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that

lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.

Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between

the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.

Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight

in homogeneous material)

(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.

(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.

PACKAGE OPTION ADDENDUM

www.ti.com 16-Oct-2015

Addendum-Page 2

(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation

of the previous line and the two combined represent the entire Device Marking for that device.

(6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish

value exceeds the maximum column width.

Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information

provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and

continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.

TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.

In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.

TAPE AND REEL INFORMATION

*All dimensions are nominal

Device Package

Type Package

Drawing Pins SPQ Reel

Diameter

(mm)

Reel

Width

W1 (mm)

(mm) B0

(mm) K0

(mm) P1

(mm) W

(mm) Pin1

Quadrant

LM3503ITL-25/NOPB DSBGA YPA 10 250 178.0 8.4 2.03 2.21 0.76 4.0 8.0 Q1

LM3503ITL-35/NOPB DSBGA YPA 10 250 178.0 8.4 2.03 2.21 0.76 4.0 8.0 Q1

LM3503ITL-44/NOPB DSBGA YPA 10 250 178.0 8.4 2.03 2.21 0.76 4.0 8.0 Q1

LM3503SQ-16/NOPB WQFN RGH 16 1000 178.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1

LM3503SQ-25/NOPB WQFN RGH 16 1000 178.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1

LM3503SQ-35 WQFN RGH 16 1000 178.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1

LM3503SQ-35/NOPB WQFN RGH 16 1000 178.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1

PACKAGE MATERIALS INFORMATION

www.ti.com 2-Sep-2015

Pack Materials-Page 1

*All dimensions are nominal

Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)

LM3503ITL-25/NOPB DSBGA YPA 10 250 210.0 185.0 35.0

LM3503ITL-35/NOPB DSBGA YPA 10 250 210.0 185.0 35.0

LM3503ITL-44/NOPB DSBGA YPA 10 250 210.0 185.0 35.0

LM3503SQ-16/NOPB WQFN RGH 16 1000 210.0 185.0 35.0

LM3503SQ-25/NOPB WQFN RGH 16 1000 210.0 185.0 35.0

LM3503SQ-35 WQFN RGH 16 1000 210.0 185.0 35.0

LM3503SQ-35/NOPB WQFN RGH 16 1000 210.0 185.0 35.0

PACKAGE MATERIALS INFORMATION

www.ti.com 2-Sep-2015

Pack Materials-Page 2

www.ti.com

PACKAGE OUTLINE

16X 0.3

0.2

2.6 0.1

12X 0.5

16X 0.5

0.3

1.5

0.8 MAX

4.1

3.9

B4.1

3.9

0.3

0.2

0.5

0.3

(0.1)

TYP

4214978/A 10/2013

WQFN - 0.8 mm max heightRGH0016A

WQFN

PIN 1 INDEX AREA

SEATING PLANE

16 13

(OPTIONAL)

PIN 1 ID

DETAIL

SEE TERMINAL

NOTES:

1. All linear dimensions are in millimeters. Dimensions in parenthesis are for reference only. Dimensioning and tolerancing

per ASME Y14.5M.

2. This drawing is subject to change without notice.

3. The package thermal pad must be soldered to the printed circuit board for thermal and mechanical performance.

0.1 C A B

0.05 C

SCALE 3.500

DETAIL

OPTIONAL TERMINAL

TYPICAL

www.ti.com

EXAMPLE BOARD LAYOUT

( 2.6)

0.07 MIN

ALL AROUND

0.07 MAX

ALL AROUND

16X (0.6)

16X (0.25)

(3.8)

5X ( )

VIA

0.2

12X (0.5)

(0.25) TYP

(1)

4214978/A 10/2013

WQFN - 0.8 mm max heightRGH0016A

WQFN

SYMM

SEE DETAILS

SYMM

LAND PATTERN EXAMPLE

SCALE:15X

NOTES: (continued)

4. This package is designed to be soldered to a thermal pad on the board. For more information, see QFN/SON PCB application report

in literature No. SLUA271 (www.ti.com/lit/slua271).

SOLDER MASK

OPENING

METAL

SOLDER MASK

DEFINED

METAL

SOLDER MASK

OPENING

SOLDER MASK DETAILS

NON SOLDER MASK

DEFINED

(PREFERRED)

www.ti.com

EXAMPLE STENCIL DESIGN

(3.8)

16X (0.6)

16X (0.25)

4X (1.15)

(0.25) TYP

12X (0.5)

(3.8)

(0.675)

4214978/A 10/2013

WQFN - 0.8 mm max heightRGH0016A

WQFN

NOTES: (continued)

5. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate

design recommendations.

SYMM

TYP

METAL

SOLDER PASTE EXAMPLE

BASED ON 0.125 mm THICK STENCIL

EXPOSED PAD

78% PRINTED SOLDER COVERAGE BY AREA

SCALE:15X

SYMM

MECHANICAL DATA

YPA0010

www.ti.com

TLP10XXX (Rev D)

. All linear dimensions are in millimeters. Dimensioning and tolerancing per ASME Y14.5M-1994.

B. This drawing is subject to change without notice.

4215069/A 12/12

NOTES:

0.600

±0.075

D: Max =

E: Max =

2.124 mm, Min =

1.946 mm, Min =

2.063 mm

1.885 mm

IMPORTANT NOTICE

Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other

changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest

issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and

complete. All semiconductor products (also referred to herein as “components”) are sold subject to TI’s terms and conditions of sale

supplied at the time of order acknowledgment.

TI warrants performance of its components to the specifications applicable at the time of sale, in accordance with the warranty in TI’s terms

and conditions of sale of semiconductor products. Testing and other quality control techniques are used to the extent TI deems necessary

to support this warranty. Except where mandated by applicable law, testing of all parameters of each component is not necessarily

performed.

TI assumes no liability for applications assistance or the design of Buyers’ products. Buyers are responsible for their products and

applications using TI components. To minimize the risks associated with Buyers’ products and applications, Buyers should provide

adequate design and operating safeguards.

TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or

other intellectual property right relating to any combination, machine, or process in which TI components or services are used. Information

published by TI regarding third-party products or services does not constitute a license to use such products or services or a warranty or

endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the

third party, or a license from TI under the patents or other intellectual property of TI.

Reproduction of significant portions of TI information in TI data books or data sheets is permissible only if reproduction is without alteration

and is accompanied by all associated warranties, conditions, limitations, and notices. TI is not responsible or liable for such altered

documentation. Information of third parties may be subject to additional restrictions.

Resale of TI components or services with statements different from or beyond the parameters stated by TI for that component or service

voids all express and any implied warranties for the associated TI component or service and is an unfair and deceptive business practice.

TI is not responsible or liable for any such statements.

Buyer acknowledges and agrees that it is solely responsible for compliance with all legal, regulatory and safety-related requirements

concerning its products, and any use of TI components in its applications, notwithstanding any applications-related information or support

that may be provided by TI. Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards which

anticipate dangerous consequences of failures, monitor failures and their consequences, lessen the likelihood of failures that might cause

harm and take appropriate remedial actions. Buyer will fully indemnify TI and its representatives against any damages arising out of the use

of any TI components in safety-critical applications.

In some cases, TI components may be promoted specifically to facilitate safety-related applications. With such components, TI’s goal is to

help enable customers to design and create their own end-product solutions that meet applicable functional safety standards and

requirements. Nonetheless, such components are subject to these terms.

No TI components are authorized for use in FDA Class III (or similar life-critical medical equipment) unless authorized officers of the parties

have executed a special agreement specifically governing such use.

Only those TI components which TI has specifically designated as military grade or “enhanced plastic” are designed and intended for use in

military/aerospace applications or environments. Buyer acknowledges and agrees that any military or aerospace use of TI components

which have not been so designated is solely at the Buyer's risk, and that Buyer is solely responsible for compliance with all legal and

regulatory requirements in connection with such use.

TI has specifically designated certain components as meeting ISO/TS16949 requirements, mainly for automotive use. In any case of use of

non-designated products, TI will not be responsible for any failure to meet ISO/TS16949.

Products Applications

Audio www.ti.com/audio Automotive and Transportation www.ti.com/automotive

Amplifiers amplifier.ti.com Communications and Telecom www.ti.com/communications

Data Converters dataconverter.ti.com Computers and Peripherals www.ti.com/computers

DLP® Products www.dlp.com Consumer Electronics www.ti.com/consumer-apps

DSP dsp.ti.com Energy and Lighting www.ti.com/energy

Clocks and Timers www.ti.com/clocks Industrial www.ti.com/industrial

Interface interface.ti.com Medical www.ti.com/medical

Logic logic.ti.com Security www.ti.com/security

Power Mgmt power.ti.com Space, Avionics and Defense www.ti.com/space-avionics-defense

Microcontrollers microcontroller.ti.com Video and Imaging www.ti.com/video

RFID www.ti-rfid.com

OMAP Applications Processors www.ti.com/omap TI E2E Community e2e.ti.com

Wireless Connectivity www.ti.com/wirelessconnectivity

Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265

Mouser Electronics

Authorized Distributor

Click to View Pricing, Inventory, Delivery & Lifecycle Information:

Texas Instruments:

LM3503ITL-25EV LM3503ITL-25EV/NOPB