Datasheet

ManualsBrandsON SEMICONDUCTOR ManualsDev KitsPCB design board

November, 2010 − Rev. 2

1 Publication Order Number:

CAT3649/D

CAT3649

6-Channel Quad-Mode

)

LED

Driver with 32 Dimming

Levels & PWM

Description

The CAT3649 is a high efficiency Quad−Mode

fractional charge

pump that can drive up to six LEDs. The inclusion of a 1.33x fractional

charge pump mode increases the device efficiency by up to 10% over

traditional 1.5x charge pumps with no added external capacitors.

Low noise input ripple is achieved by operating at a constant

switching frequency which allows the use of small external ceramic

capacitors. The multi−fractional charge pump supports a wide range of

input voltages from 2.4 V to 5.5 V.

The LED current can be adjusted in different ways. The full−scale LED

current is set to 25 mA once the device is enabled. Analog dimming in

32 linear steps is achieved via a 1−wire pulse−dimming input (ADIM).

Further adjustment of the LED current can be done by applying a pulse

width modulation (PWM) signal on the PWM input. The PWM

dimming control is compatible with content adaptive brightness control

(CABC) for a wide range of PWM signal frequency up to 200 kHz.

The CAT3649 can be shut down by holding the ADIM or PWM

input in a logic low condition for greater than 30 ms.

ON Semiconductor’s Quad−Mode 1.33x charge pump switching

architecture is patented.

Features

• High Efficiency 1.33x Charge Pump

• Quad−mode Charge Pump: 1x, 1.33x, 1.5x, 2x

• Drives up to 6 LEDs at 25 mA Each

• PWM Dimming 100 Hz to 200 kHz for CABC

• 1−wire EZDimt 32 Linear Steps (ADIM)

• Power Efficiency up to 92%

• Low Noise Input Ripple in All Modes

• “Zero” Current Shutdown Mode

• Soft Start and Current Limiting

• Short Circuit Protection

• Thermal Shutdown Protection

• 3 mm x 3 mm, 16−pad TQFN Package

• This Device is Pb−Free, Halogen Free/BFR Free and is RoHS

Compliant

Typical Applications (Note 1)

• LCD Display Backlight

• Cellular Phones

• Digital Still Cameras

• Handheld Devices

1. Typical application circuit with external components is shown in Figure 1.

http://onsemi.com

TQFN−16

HV3 SUFFIX

CASE 510AD

PIN CONNECTIONS

MARKING DIAGRAM

VIN

VOUT

CPWM

PWM

ADIM

LED6

LED5

LED4

C1+

C1−

C2+

C2−

GND

LED1

LED2

LED3

(Top View)

JABA

AXXX

YWW

JABA = CAT3649HV3−GT2

A = Assembly Location

XXX = Last Three Digits of Assembly Lot Number

Y = Production Year (Last Digit)

WW = Production Week (Two Digits)

Device Package Shipping

†

ORDERING INFORMATION

CAT3649HV3−GT2 TQFN−16

(Pb−Free)

2,000 /

Tape & Reel

†For information on tape and reel specifications,

including part orientation and tape sizes, please

refer to our Tape and Reel Packaging Specification

Brochure, BRD8011/D.

Summary of content (14 pages)

PAGE 1
CAT3649 6-Channel Quad-Mode) LED Driver with 32 Dimming Levels & PWM Description http://onsemi.com TQFN−16 HV3 SUFFIX CASE 510AD PWM CPWM VOUT PIN CONNECTIONS VIN The CAT3649 is a high efficiency Quad−Mode® fractional charge pump that can drive up to six LEDs. The inclusion of a 1.33x fractional charge pump mode increases the device efficiency by up to 10% over traditional 1.5x charge pumps with no added external capacitors.
PAGE 2
CAT3649 Figure 1. Typical Application Circuit Table 1. ABSOLUTE MAXIMUM RATINGS Parameter Rating Unit VIN, LEDx, C1±, C2±, PWM, ADIM, CPWM voltage GND−0.3 to 6 V VOUT GND−0.3 to 7 V Storage Temperature Range −65 to +160 _C Junction Temperature Range −40 to +150 _C Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied.
PAGE 3
CAT3649 Figure 2. ADIM Dimming Timing Diagram (no CPWM, PWM high) Table 4. ELECTRICAL OPERATING CHARACTERISTICS (Notes 2 and 3) Parameter Symbol Conditions IQ 1x mode 1.33 x mode, VIN = 3 V 1.5x mode, VIN = 2.8 V 2x mode, VIN = 2.
PAGE 4
CAT3649 Figure 3. Functional Block Diagram Basic Operation This sequence repeats in the 1.33x and 1.5x mode until the driver enters the 2x mode. In 1.5x mode, the output voltage is approximately equal to 1.5 times the input supply voltage. While in 2x mode, the output is approximately equal to 2 times the input supply voltage. If the device detects a sufficient input voltage is present to drive all LED currents in 1x mode, it will change automatically back to 1x mode.
PAGE 5
CAT3649 TYPICAL PERFORMANCE CHARACTERISTICS (VIN = 3.6 V, PWM = VIN, IOUT = 120 mA (6 LEDs at 20 mA), CIN = COUT = C1 = C2 = 1 mF, CPWM = 47 nF, TAMB = 25°C unless otherwise specified.) QUIESCENT CURRENT (mA) VF = 3.3 V 2x 3 1.33x 2 1.5x 1x 1 0 LED CURRENT VARIATION (%) 4 5.0 4.5 4.0 3.5 3.0 2 1 VIN = 2.6 V 1.5x VIN = 2.9 V 1.33x VIN = 3.3 V 1x VIN = 4.0 V 0 40 80 120 TEMPERATURE (°C) Figure 4. Quiescent Current vs. Input Voltage Figure 5. Quiescent Current vs.
PAGE 6
CAT3649 TYPICAL PERFORMANCE CHARACTERISTICS 100 100 90 90 1x 80 EFFICIENCY (%) EFFICIENCY (%) (VIN = 3.6 V, PWM = VIN, IOUT = 120 mA (6 LEDs at 20 mA), CIN = COUT = C1 = C2 = 1 mF, CPWM = 47 nF, TAMB = 25°C unless otherwise specified.) 1.5x 70 1.33x 60 2x 50 40 4.0 3.5 70 1.33x 60 3.0 2.5 40 2.0 1.5x VF = 3.30 V, ILED = 20 mA VF = 3.05 V, ILED = 10 mA 50 VF = 3.30 V, ILED = 20 mA VF = 3.05 V, ILED = 10 mA 4.5 1x 80 4.2 4.0 3.8 3.6 3.4 3.
PAGE 7
CAT3649 TYPICAL PERFORMANCE CHARACTERISTICS (VIN = 3.6 V, PWM = VIN, IOUT = 120 mA (6 LEDs at 20 mA), CIN = COUT = C1 = C2 = 1 mF, CPWM = 47 nF, TAMB = 25°C unless otherwise specified.) 2.0 VOLTAGE (V) 1.6 1.2 VHI 0.8 VLO 0.4 0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 INPUT VOLTAGE (V) Figure 16. ADIM, PWM VHI VLO vs. VIN Figure 17. Power Down Delay (1x Mode) Figure 18. Operating Waveforms in 1x Mode Figure 19. Switching Waveforms in 1.33x Mode Figure 20. Switching Waveforms in 1.5x Mode Figure 21.
PAGE 8
CAT3649 TYPICAL PERFORMANCE CHARACTERISTICS (VIN = 3.6 V, PWM = VIN, IOUT = 120 mA (6 LEDs at 20 mA), CIN = COUT = C1 = C2 = 1 mF, CPWM = 47 nF, TAMB = 25°C unless otherwise specified.) 4.0 30 3.0 2.5 2.0 1.5 1.0 0 50 100 150 200 20 20 mA 15 10 5 1x Mode 0.5 0 25 mA 25 LED CURRENT (mA) OUTPUT VOLTAGE (V) 3.5 250 0 300 0 50 100 150 200 250 300 LOAD CURRENT (mA) LED PIN VOLTAGE (mV) Figure 22. Foldback Current Limit Figure 23. LED Current vs. LED Pin Voltage Figure 24.
PAGE 9
CAT3649 Table 5. PIN DESCRIPTION Pin No Name Function 1 C1+ Bucket capacitor 1 Positive terminal 2 C1− Bucket capacitor 1 Negative terminal 3 C2+ Bucket capacitor 2 Positive terminal 4 C2− Bucket capacitor 2 Negative terminal 5 GND Ground Reference 6 LED1 LED1 cathode terminal. 7 LED2 LED2 cathode terminal. 8 LED3 LED3 cathode terminal. 9 LED4 LED4 cathode terminal. 10 LED5 LED5 cathode terminal. 11 LED6 LED6 cathode terminal.
PAGE 10
CAT3649 Current Selection Table 6. DIMMING LEVELS After power−up and once enabled, the LED current is set initially to the full scale of 25 mA. The number of pulses (n) on the ADIM input decreases the current value as follows: LED current [mA] + 25 ǒ3232* nǓ LED Current (Typical) [mA] Dimming Pulses [n] 25.0 0 24.2 1 23.4 2 22.6 3 21.8 4 21.0 5 20.2 6 19.4 7 18.6 8 (eq. 1) The full scale current is calculated from the above formula with n equal to zero.
PAGE 11
CAT3649 Figure 28. ADIM Dimming Timing Diagram (no CPWM, PWM high) CPWM Filtering Capacitor f PWM w 40 The PWM input signal controls the LED current proportionally to its duty cycle. When the LED driver operates in PWM dimming mode, the CPWM capacitor minimizes the LED current ripple. This prevents audio noise from the LED driver output capacitors as the PWM signal is converted into a near DC current internally.
PAGE 12
CAT3649 Unused LED Channels SHORT LED Detection For applications with five LEDs or less, it is required to tie the unused LED pin(s) directly to VOUT (see Figure 30). If the LED forward voltage (VF = VOUT – LED pin voltage) is less than 1 V, the channel is disabled and removed from signaling charge pump mode changes. A 5 mA (typical) test current is placed in the (shorted) channel. In case the LED short goes away and VF is higher than 1 V, the channel resumes normal operation. 1 mF 2.4 V to 5.
PAGE 13
CAT3649 PACKAGE DIMENSIONS TQFN16, 3x3 CASE 510AD−01 ISSUE A A D e b L E E2 PIN#1 ID PIN#1 INDEX AREA A1 TOP VIEW SIDE VIEW SYMBOL MIN NOM MAX A 0.70 0.75 0.80 A1 0.00 0.02 0.05 A3 BOTTOM VIEW 0.20 REF b 0.18 0.25 0.30 D 2.90 3.00 3.10 D2 1.40 −−− 1.80 E 2.90 3.00 3.10 E2 1.40 −−− 1.80 e L D2 A FRONT VIEW 0.50 BSC 0.30 0.40 A3 A1 0.50 Notes: (1) All dimensions are in millimeters. (2) Complies with JEDEC MO-220. http://onsemi.
PAGE 14
CAT3649 Example of Ordering Information (Notes 4 to 7) 4. 5. 6. 7. 8. Prefix Device # Suffix CAT 3649 HV3 −G T2 Company ID (Optional) Product Number 3649 Package HV3: TQFN Lead Finish G: NiPdAu Tape & Reel (Note 8) T: Tape & Reel 2: 2,000 / Reel All packages are RoHS−compliant (Lead−free, Halogen−free). The standard lead finish is NiPdAu. The device used in the above example is a CAT3649HV3−GT2 (TQFN, NiPdAu, Tape & Reel, 2,000/Reel).