Datasheet

ManualsBrandsON SEMICONDUCTOR ManualsDev KitsPCB design board

April, 2010 − Rev. 3

1 Publication Order Number:

CAT3637/D

CAT3637

6-Channel Programmable

High Efficiency

Quad-Mode

)

LED Driver

Description

The CAT3637 is a high efficiency Quad−Mode fractional charge

pump that can drive up to six LEDs programmable by a 1−wire digital

interface. The inclusion of a 1.33x fractional charge pump mode

increases 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 2.5 V to 5.5 V.

The EN/SET logic input functions as a chip enable and a digital

programming interface for setting the current in the LED channels.

The 1−wire pulse−programming interface supports 15 linear steps

from zero current to 30 mA full−brightness in 2 mA steps.

The device is available in a tiny 16−pad TQFN 3 x 3 mm package

with a maximum height of 0.8 mm.

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 6 LEDs Between 30 mA and 0 mA Each

• 1−wire EZDimt Interface with 2 mA Step

• 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

• Tiny 3 mm x 3 mm, 16−pad TQFN Package

• These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS

Compliant

Applications

• LCD Display Backlight

• Cellular Phones

• Digital Still Cameras

• Handheld Devices

http://onsemi.com

TQFN−16

HV3 SUFFIX

CASE 510AD

PIN CONNECTIONS

MARKING DIAGRAM

Device Package Shipping

ORDERING INFORMATION

CAT3637HV3−GT2

(Note 1)

TQFN−16

(Pb−Free)

2,000/

Tape & Reel

1. NiPdAu Plated Finish (RoHS−compliant).

EN/SET

GND

C2−

C2+

C1−

C1+

LED6

LED5

LED4

LED3

LED2

LED1

VOUT

VIN

(Top View)

JAAM

AXXX

YWW

JAAM = CAT3637HV3−GT2

A = Assembly Location

XXX = Last Three Digits of Assembly Lot Number

Y = Production Year (Last Digit)

WW = Production Week (Two Digits)

Summary of content (14 pages)

PAGE 1
CAT3637 6-Channel Programmable High Efficiency Quad-Mode) LED Driver Description NC NC GND EN/SET 1 LED6 C2− LED5 C2+ LED4 C1− LED3 C1+ VIN High Efficiency 1.33x Charge Pump Quad−Mode Charge Pump: 1x, 1.33x, 1.
PAGE 2
CAT3637 1 mF VIN 2.5 V to 5.5 V CIN C1− C1+ C2− C2+ VIN VOUT 1 mF 1−Wire Programming 1 mF CAT3637 EN/SET GND VOUT LED1 LED2 LED3 LED4 LED5 LED6 COUT 1 mF Figure 1. Typical Application Circuit Table 1. ABSOLUTE MAXIMUM RATINGS Parameter Rating Unit VIN, LEDx, C1±, C2± voltage 6 V VOUT Voltage 7 V EN/SET Voltage VIN + 0.
PAGE 3
CAT3637 Table 3. ELECTRICAL OPERATING CHARACTERISTICS (over recommended operating conditions unless specified otherwise) VIN = 3.6 V, EN = High, TAMB = 25°C Name Symbol Conditions IQ Quiescent Current 1x mode, VIN = 4.2 V 1.33x mode, VIN = 3.3 V 1.5x mode, VIN = 2.8 V 2x mode, VIN = 2.5 V IQSHDN Shutdown Current VEN = 0 V ILED−ACC LED Current Accuracy 2 mA ≤ ILED ≤ 30 mA ILED−DEV LED Channel Matching Min Typ Max 1.5 2.8 3.7 3.8 mA 1 I LED * I LEDAVG Units mA ±3 % ±1 % 0.5 3.5 3.
PAGE 4
CAT3637 Table 4. RECOMMENDED EN/SET TIMING (For 2.5 ≤ VIN ≤ 5.5 V, over full ambient temperature range −40° to +85°C.) Name Symbol Conditions Min Typ Max Units 100 ms TLO EN/SET program low time 0.2 THI EN/SET program high time 0.2 ms EN/SET low time to shutdown 1.5 ms TOFF TD LED current settling time 10 ms THI EN/SET TLO TD LED Current Shutdown 0 mA TOFF 28 mA 2 mA 4 mA 30 mA 6 mA 0 mA 2 mA Figure 2. EN/SET One Wire Addressable Timing Diagram http://onsemi.
PAGE 5
CAT3637 TYPICAL PERFORMANCE CHARACTERISTICS (VIN = 3.6 V, IOUT = 120 mA (6 LEDs at 20 mA), CIN = COUT = C1 = C2 = 1 mF, TAMB = 25°C unless otherwise specified.) 100 100 VF = 3.3 V VF = 3.3 V 1.33x 1.5x 1x 80 2x 70 60 80 70 60 4.5 4.0 3.5 3.0 2.5 40 2.0 4.0 3.8 3.6 3.4 3.2 INPUT VOLTAGE (V) Figure 3. Efficiency vs. Input Voltage Figure 4. Efficiency vs. Li−Ion Voltage 3.0 10 8 LED CURRENT VARIATION (%) VF = 3.3 V 6 4 2 0 −2 −4 −6 5.5 5.0 4.5 4.0 3.5 3.0 2.
PAGE 6
CAT3637 TYPICAL PERFORMANCE CHARACTERISTICS (VIN = 3.6 V, IOUT = 120 mA (6 LEDs at 20 mA), CIN = COUT = C1 = C2 = 1 mF, TAMB = 25°C unless otherwise specified.) 10 VF = 3.3 V 1.1 OUTPUT RESISTANCE (W) SWITCHING FREQUENCY (MHz) 1.2 1.5x Mode 1.0 0.9 0.8 1.33x, 2x Mode 0.7 0.6 −40 −20 0 20 40 60 8 6 1.33x 1.5x 4 2 0 80 2x 1x 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 TEMPERATURE (°C) INPUT VOLTAGE (V) Figure 8. Switching Frequency vs. Temperature Figure 9. Output Resistance vs.
PAGE 7
CAT3637 TYPICAL PERFORMANCE CHARACTERISTICS (VIN = 3.6 V, IOUT = 120 mA (6 LEDs at 20 mA), CIN = COUT = C1 = C2 = 1 mF, TAMB = 25°C unless otherwise specified.) Figure 14. Power Up Delay (1x Mode) Figure 15. Power Down Delay (1x Mode) Figure 16. Operating Waveforms in 1x Mode Figure 17. Switching Waveforms in 1.33x Mode Figure 18. Switching Waveforms in 1.5x Mode Figure 19. Switching Waveforms in 2x Mode http://onsemi.
PAGE 8
CAT3637 TYPICAL PERFORMANCE CHARACTERISTICS (VIN = 3.6 V, IOUT = 120 mA (6 LEDs at 20 mA), CIN = COUT = C1 = C2 = 1 mF, TAMB = 25°C unless otherwise specified.) 4.0 OUTPUT VOLTAGE (V) 3.5 3.0 2.5 1x Mode 2.0 1.5 1.0 0.5 0 0 100 200 300 400 500 OUTPUT CURRENT (mA) Figure 20. Foldback Current Limit Figure 21. LED Brightness Levels Figure 22. LED Settling Time http://onsemi.
PAGE 9
CAT3637 Table 5.
PAGE 10
CAT3637 Simplified Block Diagram C1− VIN C1+ C2− C2+ VOUT 1x mode (LDO) 1.33x, 1.5x, 2x Charge Pump 0.8, 1.1 MHz Oscillator EN/SET Mode Control LED1 LED2 LED3 LED4 100 kΩ Serial Interface Reference Voltage Registers Current Setting DAC LED5 LED6 6 Current Regulators GND Figure 23. CAT3637 Functional Block Diagram Basic Operation At power−up, the CAT3637 starts operating in 1x mode where the output will be approximately equal to the input supply voltage (less any internal voltage losses).
PAGE 11
CAT3637 LED Current Setting sequence can be repeated. The EN/SET pin can be pulsed at high frequency 15 times to decrement the current by 2 mA or to program the current from 0 mA to 30 mA. The maximum EN/SET signal frequency for programming the LED current is 2.5 MHz. To power−down the device and turn−off all current sources, the EN/SET input should be kept low for a duration TOFF of 1.5 ms or more. The driver typically powers−down with a delay of about 1 ms.
PAGE 12
CAT3637 Unused LED Channels VOUT, then the channel is switched off and a 200 mA test current is placed in the channel to sense when the channel moves below VOUT – 1 V. For applications with 5 LEDs or less, unused LEDs can be disabled by connecting the LED pin directly to VOUT, as shown on Figure 26. If LED pin voltage is within 1 V of 1 mF 2.5 V to 5.5 V VIN CIN 1 mF 1−Wire Programming 1 mF C1− C1+ C2− C2+ VIN VOUT CAT3637 EN/SET GND VOUT COUT LED1 LED2 LED3 LED4 LED5 LED6 1 mF Figure 26.
PAGE 13
CAT3637 PACKAGE DIMENSIONS TQFN16, 3x3 CASE 510AD−01 ISSUE A A D e b L E2 E 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
CAT3637 Example of Ordering Information (Note 5) 3. 4. 5. 6. 7. Prefix Device # Suffix CAT 3637 HV3 −G T2 Company ID (Optional) Product Number 3637 Package HV3: TQFN 3 x 3 mm Lead Finish G: NiPdAu Tape & Reel (Note 7) 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 CAT3637HV3−GT2 (TQFN, NiPdAu, Tape & Reel, 2,000/Reel).