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LM3433

BST

CSP

CSN

BST2

DMO

DIMR

COMP

ADJ

DIM

CGND

0.47 PF

2.2 PF

0.01

-12V

GND

4.7 PF

+3.3V

DIM

44.2k

0.1

ADJ

-12V

270 pF

22 PF

6 PH

0.01 LED CATHODE

LED ANODE

LED

LM3433

www.ti.com

SNVS535C –OCTOBER 2007–REVISED MAY 2013

LM3433 Common Anode Capable High Brightness LED Driver

with High Frequency Dimming

Check for Samples: LM3433

FEATURES

DESCRIPTION

The LM3433 is an adaptive constant on-time DC/DC

• Operating Input Voltage Range of -9V to -14V

buck (step-down) constant current controller (a true

w.r.t. LED Anode

current source). The LM3433 provides a constant

• Control Inputs Referenced to the LED Anode

current for illuminating high power LEDs. The output

• Output Current Greater than 6A

configuration allows the anodes of multiple LEDs to

be tied directly to the ground referenced chassis for

• Greater than 30kHz PWM Frequency Capable

maximum heat sink efficacy. The high frequency

• Negative Output Voltage Capability Allows

capable architecture allows the use of small external

LED Anode to be Tied Directly to Chassis for

passive components and no output capacitor while

Maximum Heat Sink Efficacy

maintaining low LED ripple current. Two control

inputs are used to modulate LED brightness. An

• No Output Capacitor Required

analog current control input is provided so the

• Up to 1MHz Switching Frequency

LM3433 can be adjusted to compensate for LED

• Low I

, 1mA Typical

manufacturing variations and/or color temperature

• Soft Start correction. The other input is a logic level PWM

control of LED current. The PWM functions by

• Adaptive Programmable ON Time Allows for

shorting out the LED with a parallel switch allowing

Constant Ripple Current

high PWM dimming frequencies. High frequency

• 24-pin WQFN Package

PWM dimming allows digital color temperature

control, interference blanking, field sequential

APPLICATIONS

illumination, and brightness control. Additional

features include thermal shutdown, V

under-voltage

• LCD Backlighting

lockout, and logic level shutdown mode. The LM3433

• Projection Systems

is available in a low profile 24-pin WQFN package.

• Solid State Lighting

• Automotive Lighting

TYPICAL APPLICATION CIRCUIT

Please 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.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (20 pages)

PAGE 1
LM3433 www.ti.com SNVS535C – OCTOBER 2007 – REVISED MAY 2013 LM3433 Common Anode Capable High Brightness LED Driver with High Frequency Dimming Check for Samples: LM3433 FEATURES DESCRIPTION • The LM3433 is an adaptive constant on-time DC/DC buck (step-down) constant current controller (a true current source). The LM3433 provides a constant current for illuminating high power LEDs.
PAGE 2
LM3433 SNVS535C – OCTOBER 2007 – REVISED MAY 2013 www.ti.com 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.
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LM3433 www.ti.com SNVS535C – OCTOBER 2007 – REVISED MAY 2013 PIN DESCRIPTIONS (continued) Pin Name 19 DIMR LED dimming FET gate drive return. Tie to LED cathode. Function 20 DIMO LED dimming FET gate drive output. DIMO is a driver that switches between DIMR and BST2. 21 BST2 DIMO high side drive supply pin. Tie a 0.1µF between BST2 and CGND. 22 NC 23 CSN Current sense amplifier inverting input. Connect to current sense resistor negative terminal.
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LM3433 SNVS535C – OCTOBER 2007 – REVISED MAY 2013 ABSOLUTE MAXIMUM RATINGS www.ti.com (1) VALUE / UNIT VIN, EN, DIM, ADJ to CGND -0.3V to +7V COMP, SS to VEE -0.3V to +7V BST to HS -0.3V to +7V VCC to VEE -0.3V to +7.5V CGND, DIMR, CSP, CSN, TON to VEE -0.3V to +16V HS to VEE (2) -0.3V to +16V LS to VEE -0.3V to +0.3V HO output HS-0.3V to BST+0.3V DIMO to DIMR -0.3V to +7V LO output LS-0.3V to VCC +0.3V BST2 to VEE -0.3V to 22.
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LM3433 www.ti.com SNVS535C – OCTOBER 2007 – REVISED MAY 2013 ELECTRICAL CHARACTERISTICS Specifications in standard type face are for TJ = 25°C and those with boldface type apply over the full Operating Temperature Range ( TJ = −40°C to +125°C). Minimum and Maximum limits are specified through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = +25ºC, and are provided for reference purposes only.
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LM3433 SNVS535C – OCTOBER 2007 – REVISED MAY 2013 www.ti.com ELECTRICAL CHARACTERISTICS (continued) Specifications in standard type face are for TJ = 25°C and those with boldface type apply over the full Operating Temperature Range ( TJ = −40°C to +125°C). Minimum and Maximum limits are specified through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = +25ºC, and are provided for reference purposes only.
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LM3433 www.ti.com SNVS535C – OCTOBER 2007 – REVISED MAY 2013 TYPICAL PERFORMANCE CHARACTERISTICS Efficiency vs. LED Forward Voltage (VCGND-VEE = 9V) Efficiency vs. LED Forward Voltage (VCGND-VEE = 12V) 97 96 2A 4A 6A 8A 96 94 94 EFFICIENCY (%) EFFICIENCY (%) 95 93 92 91 90 2A 4A 6A 8A 89 88 87 1 2 3 4 5 92 90 88 86 6 84 7 1 2 3 VLED (V) 5 6 7 VLED (V) Figure 2. Figure 3. Efficiency vs. LED Forward Voltage (VCGND-VEE = 14V) VSENSE vs. VADJ (VIN = 3.
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LM3433 SNVS535C – OCTOBER 2007 – REVISED MAY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) VSENSE vs. Temperature (ADJ = 1.0V) Average LED Current vs. DIM Duty Cycle (30kHz dimming, ILED = 6A nominal) 61 7 AVERAGE LED CURRENT (A) 60.8 60.6 VSENSE (mV) 60.4 60.2 60 59.8 59.6 59.4 59.2 59 -40 -20 0 20 40 60 5 4 3 2 1 0 80 AMBIENT TEMPERATURE (°C) 0 10 20 30 40 50 60 70 80 90 100 DIM DUTY CYCLE (%) Figure 8. Figure 9.
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LM3433 www.ti.com SNVS535C – OCTOBER 2007 – REVISED MAY 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) 30kHz PWM Dimming Waveform Showing Inductor Ripple Current ILED = 6A nominal, VIN = 3.3V, VEE = -12V Top trace: DIM input, 2V/div, DC Bottom trace: ILED, 2A/div, DC T = 10µs/div Figure 12.
PAGE 10
LM3433 SNVS535C – OCTOBER 2007 – REVISED MAY 2013 www.ti.com Operation CURRENT REGULATOR OPERATION The LM3433 is a controller for a Continuous Conduction Buck Converter. Because of its buck topology and operation in the continuous mode, the output current is very well controlled. It only varies within a switching frequency cycle by the inductor ripple current. This ripple current is normally set at 10% of the DC current.
PAGE 11
LM3433 www.ti.com SNVS535C – OCTOBER 2007 – REVISED MAY 2013 When the reference on ADJ is adjustable, VSENSE and ILED can be adjusted within the linear range of the ADJ pin. This range has the following limitations: 0.3V < VADJ < (The greater of 1.5V or (VIN - 1.9V)) (4) When VADJ is less than this linear range the VSENSE is specified by design to be less than or equal to 0.3V/16.667.
PAGE 12
LM3433 SNVS535C – OCTOBER 2007 – REVISED MAY 2013 www.ti.com POWER FET SELECTION FETs should be chosen so that the I2RDSON loss is less than 1% of the total output power. Analysis shows best efficiency with around 8mΩ of RDSON and 15nC of gate charge for a 6A application. All of the switching loss is in the main switch FET. An additional important parameter for the synchronous FET is reverse recovery charge (QRR). High QRR adversely affects the transient voltages seen by the IC.
PAGE 13
LM3433 www.ti.com SNVS535C – OCTOBER 2007 – REVISED MAY 2013 APPLICATION INFORMATION 0.1 PF 44.2k LED ANODE ADJ ADJ EN EN DIM DIM DMO TON DIMR -12V BST2 CSP 270 pF CSN Q3 Q1 HO LED HS 0.47 PF LM3433 BST LED CATHODE Q2 LO 22 PF LS SS COMP 4.7 PF VEE VIN 100 CGND +3.3V 0.01 6 PH VCC 2.2 PF GND 0.01 PF 0.1 PF -12V Figure 13. 2A to 6A Output Application Circuit 0.1 PF 68.
PAGE 14
LM3433 SNVS535C – OCTOBER 2007 – REVISED MAY 2013 www.ti.com Table 1. Some Recommended Inductors (Others May Be Used) Manufacturer Inductor Contact Information Coilcraft GA3252-AL and SER1360 series www.coilcraft.com 800-322-2645 Coiltronics HCLP2 series www.coiltronics.com Pulse PB2020 series www.pulseeng.com Table 2. Some Recommended Input/Bypass Capacitors (Others May Be Used) Manufacturer Capacitor Contact Information Vishay Sprague 293D, 592D, and 595D series tantalum www.vishay.
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LM3433 www.ti.com SNVS535C – OCTOBER 2007 – REVISED MAY 2013 REVISION HISTORY Changes from Revision B (May 2013) to Revision C • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
PAGE 16
PACKAGE OPTION ADDENDUM www.ti.
PAGE 17
PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant LM3433SQ/NOPB WQFN RTW 24 1000 178.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1 LM3433SQX/NOPB WQFN RTW 24 4500 330.0 12.4 4.3 4.3 1.3 8.0 12.
PAGE 18
PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM3433SQ/NOPB WQFN RTW 24 1000 210.0 185.0 35.0 LM3433SQX/NOPB WQFN RTW 24 4500 367.0 367.0 35.
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MECHANICAL DATA RTW0024A SQA24A (Rev B) www.ti.
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