SC441ATETRT Semtech, SC441ATETRT Datasheet
SC441ATETRT
Specifications of SC441ATETRT
Available stocks
Related parts for SC441ATETRT
SC441ATETRT Summary of contents
Page 1
... The internal thermal shutdown protects the IC from overheating at abnormal conditions. The SC441A is available in a thermally-enhanced TSSOP- 20 EDP package VIN VOUT VOUT EN OVPIN OVPIN FFLAG OVPRTN PWM SC441A 4 IO1-4 IO1- 4 COMP COMP IOSET IOSET AGND AGND IOGND SS SS EDP PGND PGND PGND SC441A Strings 10 www.semtech.com 1 ...
Page 2
... Marking Information SC441A : Part Number yyww = Date (Example: 0952) xxxxxx = Semtech Lot# (Example: A94A01) © 2010 Semtech Corporation Ordering Information 2 1 Device SC441ATETRT IO3 D SC441AEVB IO4 Notes: PGND (1) Available in tape and reel only. A reel contains 2,500 devices. SW (2) Available in lead-free package only. Device is WEEE and RoHS ...
Page 3
... Compensation Sourcing Current Sinking Current © 2010 Semtech Corporation Recommended Operating Conditions Input Voltage Range ……………………………… 4.5V~21V 22W Output Voltage …………………………………… 36V LED Current … ...
Page 4
... Leakage Current Overshoot Protection Threshold Overshoot Protection Hysteresis Over-Temperature Protection Thermal Shutdown Temperature Thermal Shutdown Hysteresis Notes: (1) Guaranteed by design. (2) For achievable PWM dimming minimum pulse-width in applications, see the corresponding curves in Typical Characteristics. © 2010 Semtech Corporation Symbol Conditions V V EN_H, PWM_H V V ...
Page 5
... VIN = 4.5V 0.89 0.87 0.85 0.83 0.81 VIN = 21V 0.79 VOUT = VIN + 3V 0.77 0.75 -40 25 Temperature ( C) o © 2010 Semtech Corporation UVLO Hysteresis vs. Temperature 247 246 SS SINK/SOURCE 245 244 243 242 241 240 239 238 237 105 -40 25 Temperature ( ...
Page 6
... PWM Dimming Minimum Pulse Width vs. PWM Dimming Frequency 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 0 PWM Dimming Frequency (kHz) Condition: VIN = 12V, VOUT = 30V / 150mA x 4 strings © 2010 Semtech Corporation OVPRTN Saturation Voltage vs. Temperature 100uA OVPRTN 160 -40 25 Temperature ( C) o ...
Page 7
... PWM Dimming Minimum Pulse Width vs. PWM Dimming Frequency 0.1 0.2 0 PWM Dimming Frequency (kHz) Condition: VIN = 12V, VOUT = 34.5V / 10mA x 4 strings © 2010 Semtech Corporation 150mA PWM Dimming Minimum Pulse Width vs. PWM Dimming Frequency PWM Dimming Frequency (kHz) Condition: VIN = 12V, VOUT = 34.5V / 150mA x 4 strings ...
Page 8
... Output = 30V / 150mA x 4 LED strings Main Power Switching Waveform VSW (20V/DIV) VOUT Accoupling (200mV/DIV) Time (1uS/DIV) Conditions: VIN = 12V, Output = 36V / 150mA x 4 LED strings © 2010 Semtech Corporation Shut Down VIN (5V/DIV) VSS (2V/DIV) VSW (20V/DIV) VOUT (20V/DIV) Time (200mS/DIV) ...
Page 9
... VOUT (20V/DIV) IO1 (10V/DIV) IO2 (1V/DIV) Time (10mS/DIV) Conditions: VIN = 12V, IO2 LED String is open circuit, Output = 36V / 150mA x 3 LED strings © 2010 Semtech Corporation LED Short Circuit Protection VIN (10V/DIV) VOUT (20V/DIV) IO1 (5V/DIV) IO2 (1V/DIV) Time (10mS/DIV) ...
Page 10
... IO3 Provides constant current source to LED string 3. EDP Solder to the ground plane of the PCB. Note: Any unused IO pin should be pulled up to VIN. EN STATUS 0 backlight disable 1 backlight enable Note: When the boost is turned OFF and disabled. © 2010 Semtech Corporation SC441A 10 www.semtech.com ...
Page 11
... FFLAG ONE IO CHANNEL SHOWN LED OPEN/SHORT/OVERSHOOT CIRCUIT PROTECTION IO1 LED CURRENT SETTING IOSET IOGND VOUT OVP OVPIN OVP OVPRTN Fault Detect 0.9mA 0.9mA SS HICCUP © 2010 Semtech Corporation 4 HICCUP FAULT DISABLE1 CURRENT SOURCE HICCUP CONTROL 3V3 LOGIC HICCUP 4.5uA 4.5uA 1uA 1uA Figure 1 ...
Page 12
... SS pin voltage. When the SS pin voltage reaches its switching threshold, output © 2010 Semtech Corporation voltage increases. Proper decoupling is required on the VIN pin, especially for a lower input voltage condition. A 22µF, 6.3V rated X5R ceramic capacitor is recommended for a 5V input system ...
Page 13
... If some designers do not want pulse skipping mode, based on the conditions provided above, © 2010 Semtech Corporation there are some choices. 1) Leave some room between Vin range and Vo. 2) Operate the Boost converter at normal load (less Ro) 3) Increases the Boost inductance (L) ...
Page 14
... VOUT falls below to VIN, the shorted LED detection latches are reset and a new soft-start se- quence is initiated to resume normal operation. Thermal Shutdown (TSD) © 2010 Semtech Corporation If the thermal shutdown temperature of 150 a hiccup sequence is initiated where the boost converter and all IO current sources are turned off discharged by a 1µ ...
Page 15
... C_dcple is about 444pF. One could use 390pF or less in the circuit. If I_LED=100mA, Vo=13.5V, the calculated upper bound of C_dcple is about 4.44nF. © 2010 Semtech Corporation One may use 3.9nF or less in the circuit. In some appli- cations, circuit designers tend to select the decoupling capacitors in the range of (100pF ~ 1nF) ...
Page 16
... LED current at a fixed value. Overall, this allows usage of small output caps while ensuring precision LED current regulation. Although © 2010 Semtech Corporation the mechanics of regulation and frequency dependence may be complex, actual selection of output capacitor can be simplified because this capacitor is mainly selected for the output ripple of the converter ...
Page 17
... IO pins from noise influence. C14~C17 should be placed close to each corresponding IO pin. Use an isolated local AGND plane underneath the con- troller and tie it to the negative side of output capacitor through R14 for better noise immunity. © 2010 Semtech Corporation SC441A 17 www.semtech.com ...
Page 18
... C16, C17 C8 R1, R14 2 10 R2, R3, R4 R8, R10, R11 R12, R13 © 2010 Semtech Corporation 10K 10K 11 FFLAG 12 VIN C1 C1 1nF 1nF 13 OVPRTN 10K 10K 2.2uF/25V 2.2uF/25V 14 OVPIN SC441A SC441A PGND 220K 220K 16 SW VOUT PGND R10 R10 IO4 20 IO3 ...
Page 19
... N/2 TIPS aaa C SEATING PLANE C EXPOSED PAD NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. DATUMS -A- AND 3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. © 20010 Semtech Corporation © 2010 Semtech Corporation DIM MIN A A1 .001 .031 b .007 c ...
Page 20
... CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. 3. THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD SHALL BE CONNECTED TO A SYSTEM GROUND PLANE. FAILURE MAY COMPROMISE THE THERMAL AND/OR FUNCTIONAL PERFORMANCE OF THE DEVICE. Contact Information © 2010 Semtech Corporation F DIM ...