SC4538ULTRT Semtech, SC4538ULTRT Datasheet
SC4538ULTRT
Specifications of SC4538ULTRT
Available stocks
Related parts for SC4538ULTRT
SC4538ULTRT Summary of contents
Page 1
... SC4538 if the BL pin is fl oating or shorted to ground. The SC4538 is available in an MLPD-8 pin 2mm x 2mm x 0.6mm package, with a rated temperature range of -40°C to +85° OUT C IN SC4538 EN R ISET ISET C COMP R COMP COMP BL GND © 2008 Semtech Corporation SC4538 for LEDs C OUT 1 ...
Page 2
... MLPD: 2mm x 2mm 8 Lead θ = 74°C/W JA Marking Information FE0 yw FE0 = Marking code for SC4538 yw = Date Code Ordering Information Device SC4538ULTRT SC4538EVB Note (1) Available in tape and reel only. A reel contains 3,000 devices. (2) Lead-free package only. Device is WEEE and RoHS compliant. 7 GND 6 BL ...
Page 3
Absolute Maximum Ratings Supply Voltage ( -0.3 to +20.0 LX Voltage, Output Voltage (V) . ...
Page 4
Electrical Characteristics (continued) Parameter Boost Converter Characteristics (continued) Switch Leakage Current Switch Saturation Voltage COMP Sourcing Current COMP Sinking Current OUT Over-Voltage Protection OUT Internal Pull-Down Current OUT Bias Current OUT Leakage Current (1)(2) PWM Dimming Frequency Range (1)(2) PWM ...
Page 5
Typical Characteristics All data taken with V = 20V (6 white LEDs), R OUT ISET Effi ciency vs. I 100 (mA) BL Effi ciency vs. Input Voltage 90 86 ...
Page 6
Typical Characteristics (continued) PWM Operation at 200Hz and 1% Duty Cycle V (20V/div (20mA/div) OUT V (10V/div) OUT V (2V/div) EN 2ms/div PWM Operation at 32kHz and 50% Duty Cycle V (20V/div (20mA/div) OUT V (20V/div) ...
Page 7
Typical Characteristics (continued) Typical Waveforms (20V/div (50mV/div (50V/div) OUT 1μs/div Typical Waveforms (20V/div (50mV/div (50mV/div) OUT 1μs/div Waveforms During Over-Voltage Protection V (50V/div (20mA/div) ...
Page 8
Pin Descriptions Pin # Pin Name ISET 4 COMP 5 OUT GND Thermal Pad Pin Function Collector of the internal power transistor — connect to the boost inductor and ...
Page 9
Block Diagram Thermal UVLO Shutdown 8 IN Reference and Internal Regulator EN 2 ADJ 6 BL OUT 5 OVP Comparator OSC Error Signal Selection and Summation ADJ EN LED Setpoint 3 ISET SC4538 1 RSENSE 7 Sense ...
Page 10
Applications Information Applications Information General Description The SC4538 contains an 800kHz fi xed-frequency current- mode boost converter and an independent LED current regulator. The LED current set point is chosen using an external resistor, while the PWM controller operates inde- ...
Page 11
Applications Information (continued) must endure high voltage for an extended period of time. Soft-Start The soft-start mode reduces in-rush current by utilizing the external compensation network. As the error amplifi er slowly charges the COMP node voltage, the duty cycle ...
Page 12
Applications Information (continued) Diode Selection A Schottky diode with a reverse voltage of 40V and a forward current rating of 1A should be used with this device for optimum per formance. The Central Semiconductor Corporation CMOSH- suitable diode ...
Page 13
Outline Drawing – MLPD-UT-8 2x2 A PIN 1 INDICATOR (LASER MARK) aaa C A1 LxN E/2 e NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS ( ANGLES IN DEGREES ). COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS. ...
Page 14
... SHALL BE CONNECTED TO A SYSTEM GROUND PLANE. FAILURE MAY COMPROMISE THE THERMAL AND/OR FUNCTIONAL PERFORMANCE OF THE DEVICE. Contact Information Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805) 498-2111 Fax: (805) 498-3804 www.semtech.com DIMENSIONS DIM INCHES MILLIMETERS (.077) (1 ...