Document
SC4541
POWER MANAGEMENT Features
High Frequency LED Driver with Integrated Schottky and Simple Interconnect
Description
VIN Range — 2.9V to 22V VOUT Range — Up to 25V IOUT Range:
Up to 100mA (Boost) Up to 200mA (Buck) Drives Up to 7 Series WLEDs (Boost) Drives Up to 5 Series WLEDs (Buck) Integrated Schottky Rectifier Single-Wire LED Connect Current Mode Control Frequency — 2.0MHz No External Compensation Direct PWM Dimming 100:1 Range at 500Hz Open-LED Protection — 27V Low Shutdown Current < 1µA Package Options: Low Profile MLPD-UT, 6-pin 2x2 x0.6(mm) SOT23, 6-pin 2.9x2.8 x1.45(mm) Lead-free, Halogen-Free and WeEE/RoHS Compliant
Applications
Keypad Illumination DSC and DSLR Display Backlight Cellular Handsets Automotive Lighting
The SC4541 is a fully integrated, high voltage boost (stepup) and buck (step-down) LED driver. The input voltage range is 2.9V to 22V with output voltage up to 25V. The device is capable of driving up to 7 white LEDs. The high side sense enables a single-wire LED connection by taking advantage of the available system ground. This reduces connector cost and complexity. The device includes a current mode PWM controller, 260mA power switch, and high performance Schottky rectifier. The LED driver eliminates external compensation components for minimum solution size. The wide input voltage range and low standby current are ideal for portable devices. The high input voltage allows direct connection to multi-cell battery packs which increases operating efficiency and extends battery life. Output current is programmed with an external sense resistor up to 100mA (Boost) or 200mA (Buck). The device provides ±5% constant current accuracy across the entire operating temperature range. A logic level PWM dimming signal may be applied directly to the enable (EN) pin - for direct PWM dimming with a wide dimming range. Output OVP (over voltage protection) protects the SC4541 from open circuit faults in the LED string or connector. External OVP programming resistors are not required. The SC4541 is available in low profile MLPD-UT and SOT23,6-pin packages. The device is rated across the temperature range -40°C to +85°C.
Typical Application Circuit
VIN 2.9V to 22V
Boost Topology IOUT up to 100mA L1
C1 10μF
1μF
IN SW OUT VOUT Up to 25V
SC4541
C2 1μF
RS 10Ω
PWM Dimming
EN GND FB
7 WLED @ 20mA
Version 1.3
© 2011 Semtech Corporation
1
Pin Configuration, MLPD-UT6
IN 1
GND
2
SW 3
TOP VIEW
T
6 EN 5 FB 4 OUT
MLPD-UT: 2 x 2(mm) 6 Lead θJA = 75º C/W
Marking Information, MLPD-UT6
SC4541
Pin Configuration, SOT23-6
OUT 6
FB 5
EN 4
Top View
12 SW GND
3 IN
SOT23, 6 Lead θJA = 150º C/W
Marking Information, SOT23-6
FR7 = Code for SC4541 EW = Datecode
Ordering Information
Device
Package
SC4541SKTRT(1,2)
SOT23-6
SC4541ULTRT(1,2)
2 x 2 x 0.6(mm) MLPD-UT6
SC4541EVB-1 SC4541EVB-2
Evaluation Board, SOT23-6 Evaluation Board, MLPD-UT6
Notes: (1) Available in tape and reel only. A reel contains 3,000 devices. (2) Available in lead-free package only. Device is WEEE/RoHS compliant
and halogen-free.
LK5A = Code for SC4541 Eyww = Datecode
2
SC4541
Absolute Maximum Ratings
Supply IN Voltage(V) . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to 26 SW Voltage, OUT Voltage(V) . . . . . . . . . . . . . . . . . -0.3 to 28 FB, Enable Voltage(V) . . . . . . . . . . . . . . . . . . . . . -0.3 to VIN+0.3 ESD Protection Level(1)(kV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Recommended Operating Conditions
Supply IN Voltage (V) . . . . . . . . . . . . . . . . . . . . . . . . . . 2.9 to 22 Maximum Output Voltage (V) . . . . . . . . . . . . . . . . . . . . . . . . 25 Ambient Temperature Range (°C) . . . . . . . . . . . . . -40 to +85
Thermal Information
Thermal Resistance, Junction to Ambient(2)
MLPD-UT6(°C/W) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
SOT23-6(°C/W). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
Maximum Junction Temperature (°C) . . . . . . . . . . . . . . +125
Storage Temperature Range (°C) . . . . . . . . . . . . -65 to +150
Peak IR Reflow Temperature (10s to 30s) (°C) . . . . . . . . +300
Exceeding the above specifications may result in permanent damage to the device or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not recommended. NOTES: (1) Tested according to JEDEC standard JESD22-A114-B. (2) Calculated from package in still air, mounted to 3 x 4.5(in), 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards.
Electrical Characteristics
VIN =5V, CIN=1uF, COUT=1uF, L=10uH, TA= -40°C to 85°C, unless specified otherwise.
Parameter
Symbol
Conditions
Min Typ Max Units
Input Voltage Supply Current Shutdown Supply Current EN Logic High Voltage EN Logic Low Voltage EN Logic Bias Current Boost Converter Characteristics
VIN 2.9 22 V
IIN(Q) VI.