SC1417B MicroPower, 620kHz PWM, Step-up DC/DC Converter POWER MANAGEMENT Description Features The SC1417B is a fixed frequency, current mode step-up dc-dc converter. It operates over a wide input supply range of 1.5V to 12V, making it suitable for battery input and TFT-LCD applications. The 620kHz constant frequency oscillator minimizes the size of external components and allows simple filtering for noise sensitive environments. The integrated power NPN supports peak currents of up to 0.9A enabling the device to support 150mA at 15V from a 5V supply. The maximum switch duty cycle of 85% (typical) allows output to input voltage ratios as high as 6.5 in step-up configurations, thus allowing 2V to 12V boost operation. Operates from 1.5V to 12V supply voltage High efficiency >85% 150mA @ 15V from 5V input Internal switch peak current of 0.9A Programmable output voltage Powers up into full load Pulse-by-pulse current limit/thermal shutdown 620kHz fixed frequency current mode converter Low current shutdown mode extends battery life 18V output capability Low battery detector MSOP-8 package. Available in Lead-free package, fully WEEE and RoHS compliant Pin-for-pin compatible with LT1317B The SC1417B features a low battery detector and a 200mV reference circuit which remains active during shut down. The part consumes less than 50µA in shutdown. The low battery detect output goes low when the input battery voltage has dropped below a user programmable level. Pulse-by-pulse current limit and thermal shutdown protect the converter during load faults. Applications The SC1417B is available in a MSOP-8 surface mount package. TFT-LCD Bias supplies Constant current LED bias supplies Pagers GPS receivers Battery backup SEPIC converters Typical Application Circuit D1 L1 10uH R2 1M R3 1M SMB5819 U1 6 C1 7 47uF 3 1 IN LX LBI FB EN LBO COMP GND 5 3.3V@250mA R1 1.0M 2 8 4 VOUT = 1.22 • (1 + R1 ) R4 C2 47uF R4 604k SC1417B 2 Cells (Alkaline) R6 130k LBO OUT R5 33k C3 3.3nF Revision: August 1, 2006 1 www.semtech.com SC1417B POWER MANAGEMENT Absolute Maximum Ratings Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not implied. Parameter Symbol Maximum Units Input Supply Voltage VIN 15 V LX Input V LX -0.4 to 20 V LBI Input V LB I -0.3 to 6 V EN Input V EN -0.3 to 6 V FB Input V FB -0.3 to 6 V LBO Output V LB O -0.3 to 15 V COMP Output VCOMP -0.3 to 6 V Operating Ambient Temperature Range TA -40 to 85 °C Operating Junction Temperature Range TJ -40 to 125 °C Thermal Impedance, Junction to Ambient θJ A 163 °C/W Thermal Impedance, Junction to Case θJ C 63 °C/W Storage Temperature Range TSTG -65 to 150 °C Lead Temperature (Soldering) 10 Sec. TLEAD 300 °C Electrical Characteristics Unless otherwise specified: TA = 25°C. Values in bold apply over full operating ambient temperature range. VIN = 2V, VEN = 2V, All voltages are with respect to ground, -ve indicates current is flowing out of the pin. Parameter Input Voltage Feedback Voltage Supply Current in Shutdown Symbol Conditions Min VIN VFB = 1.22V V FB VCOMP = 600mV, LX floating IQ(OFF) VEN = 0V, VLBI = 300mV Max Units 1.5 12 V 2.0 12 1.16 Typ 1.22 1.28 V 40 55 µA 65 Supply Current in PWM Mode IQ IOUT = 0A, VCOMP = 100mV 4.3 5.8 mA Feedback Input Current IFB VFB = 1.22V 15 60 nA Error Amplifier Transconductance Gm dlCOMP = 5µA 140 240 µS 2006 Semtech Corp. 2 70 www.semtech.com SC1417B POWER MANAGEMENT Electrical Characteristics Unless otherwise specified: TA = 25°C. Values in bold apply over full operating ambient temperature range. VIN = 2V, VEN = 2V, All voltages are with respect to ground, -ve indicates current is flowing out of the pin. Parameter Symbol Error Amplifier Voltage Gain(1) Maximum Output Current, L = 22uH Power Switch Voltage Drop (1) Conditions Min AV(E.A.) (1) IOUT Typ Max 700 Units V/V VOUT = 5.0V, VIN = 2.0V 200 mA VOUT = 10V, VIN = 5.0V 250 mA VOUT = 15V, VIN = 5.0V 150 mA (VLX-GND) ILX = 500mA 150 250 mV 500 Power Switch Current Limit Switch Leakage ILIM 0°C ≤ TA ≤ 85°C 0.70 -40°C ≤ TA ≤ 85°C 0.60 0.95 1.20 A 0.01 3 µA 520 620 720 kHz ILX V LX = 5 V Internal Oscillator Frequency fOSC LX , E N open Maximum Duty Cycle %DC 80 85 Low Battery Input Voltage Threshold V LB I 190 200 180 LBI Input Current Low Battery Output Low Low Battery Detector Gain (1) % 210 mV 210 ILBI VLBI = 100mV -5 -40 nA VLBO(L) ILBO = 5µA 75 250 mV AV 1MΩ load 2000 V/V 0.6 V Enable Inputs Enable Input Voltage VIH 1.4 0.60 VIL Enable Pin Current IIH VSHDN = 0V IIL -2.3 0.25 V 300 nA -6.0 µA Notes: (1) Guaranteed by design. (2) This device is ESD sensitive. Use of standard ESD handling precautions is required. 2006 Semtech Corp. 3 www.semtech.com SC1417B POWER MANAGEMENT Pin Configuration Ordering Information TOP VIEW COMP 1 8 LBO FB 2 7 LBI EN 3 6 IN GND 4 5 LX Part Number P ackag e SC1417BIMSTR(1) MSOP-8 SC1417BIMSTRT(1)(2) MSOP-8 S C 1417B E V B Evaluation Board Note: (1) Only available in tape and reel packaging. A reel contains 2500 devices. (2) Available in lead-free packaging only. This product is fully WEEE and RoHS compliant. (MSOP-8) Pin Descriptions Pin # Pin Name Pin Function 1 COMP C ompensati on pi n for error ampli fi er. C onnect a seri es RC network from thi s pi n to ground for frequency compensation. Typical values are 33kΩ/3.3nF. Placing a 100pF - 10nF capacitor from this pin to ground reduces the output and input capacitor values required for stability at the expense of slower transient response. 2 FB Feedback pin. Connect to the output through a voltage divider to set output voltage. VOUT = 1.22 • (1 + R1 ) R4 3 EN Enable pin. Pull this pin low for shutdown mode. The device quiescent current reduces to 40µA (typ.). This pin can be left floating or pulled up to a voltage less then 6V to enable the device. 4 GND 5 LX Switch pin (the inductor and diode junction). Keep traces on this pin short and wide to minimize EMI. 6 IN Supply pin. Bypass this pin to GND with a capacitor as close to pins 4 and 6 as possible. 7 LB I Low battery detector input. Connect to IN through a voltage divider to set low battery indicator threshold. Ground. VTH(LO ) = 0.2 • (1 + 8 LB O 2006 Semtech Corp. R2 ) R6 Low battery detector open collector output. This pin pulls low when VLBI is below 200mV (typ.). Pullup using a 1MΩ resistor. 4 www.semtech.com SC1417B POWER MANAGEMENT Block Diagram COMP IN 1.22V REFERENCE ERROR AMP ENABLE EN FB COMP LX SLOPE COMP PWM LOGIC Q3 DRV 620kHz OSCILLATOR LBO LBM .05 Ohm CURRENT AMP 200mV LBI GND Marking Information Marking for MSOP-8 package yyww = Date Code (Example: 0012) xxxxxxxx = Semtech Lot No. (Example: E90101-1) 2006 Semtech Corp. 5 www.semtech.com SC1417B POWER MANAGEMENT Typical Characteristics 1.250 Feedback Voltage Supply Current in Shutdown vs. Temperature vs. Temperature 60 VIN = VEN = 2V VCOMP = 600mV LX floating 1.245 1.240 50 1.235 40 1.230 IQ(OFF) (µA) VFB (V) VIN = 2V VEN = 0V VLBI = 300mV 1.225 1.220 30 20 1.215 1.210 10 1.205 1.200 0 -50 -25 0 25 50 75 100 -50 -25 0 TA (°C) Feedback Input Current vs. Temperature vs. Temperature 75 100 75 100 75 100 50 VIN = VEN = 2V IOUT = 0A VCOMP = 100mV 5.1 4.9 VIN = VEN = 2V VFB = 1.22V 45 40 4.7 35 4.5 30 IFB (nA) IQ (mA) 50 Supply Current in PWM Mode 5.3 4.3 4.1 25 20 3.9 15 3.7 10 3.5 5 3.3 0 -50 -25 0 25 50 75 100 -50 -25 0 TA (°C) 25 50 TA (°C) Power Switch Voltage Drop Power Switch Current Limit vs. Temperature vs. Temperature 1.20 400 VIN = VEN = 2V ILX = 500mA 350 1.15 VIN = VEN = 2V 1.10 300 1.05 250 ILIM (A) (VLX - GND) (mV) 25 TA (°C) 200 150 1.00 0.95 0.90 0.85 100 0.80 50 0.75 0 0.70 -50 -25 0 25 50 75 -50 100 2006 Semtech Corp. -25 0 25 50 TA (°C) TA (°C) 6 www.semtech.com SC1417B POWER MANAGEMENT Typical Characteristics (Cont.) Internal Oscillator Frequency Low Battery Input Voltage Threshold vs. Temperature vs. Temperature 670 660 VIN = VEN = 2V 204 203 640 202 630 201 VLBI (mV) fOSC (kHz) 650 205 VIN = 3.6V VOUT = 5V IOUT = 20mA 620 610 200 199 600 198 590 197 580 196 570 195 -50 -25 0 25 50 75 100 -50 -25 0 TA (°C) Enable Voltage Threshold vs. Temperature vs. Temperature 1.0 VIN = VEN = 2V VLBI = 100mV ILBO = 10µA 0.9 75 100 75 100 VIN = 2V 0.8 0.7 VEN (V) 100 VLBO(L) (mV) 50 Low Battery Output Low 150 125 25 TA (°C) 75 50 0.6 0.5 0.4 0.3 0.2 25 0.1 0 0.0 -50 -25 0 25 50 75 100 -50 TA (°C) 2006 Semtech Corp. -25 0 25 50 TA (°C) 7 www.semtech.com SC1417B POWER MANAGEMENT Typical Characteristices (Cont.) 2-Cell to 5V Converter Efficiency 90 Efficiency (%) 80 70 60 Vin 3.0V Vin 2.2V Vin 1.65V 50 40 1 10 100 1000 Load current (mA) Scope plot of Boost Converter waveforms in Constant Brightness LED driver Vin = 3V, Vout = 11.9V, Iout = 40mA, L = 15uH Cin = 10uF, 6.3V tant. Cout = 1uF, ceramic, (see above schematic for other components used) Ch1: Switching Node, Ch2: Vout ripple, Ch4: Current in inductor, (100mA/div) Inductor current ripple = 170mA pk-pk 2006 Semtech Corp. 8 www.semtech.com SC1417B POWER MANAGEMENT Typical Application Circuits(1) D1 SMB5819 L1 25 mA out (12V compliant) 15uH VIN R2 1M R3 1M VOUT LED,3.5V U1 6 7 3 1 IN LX LBI FB EN LBO COMP C1 22uF,6.3V 5 2 LED,3.5V 8 4 GND SC1417B LED,3.5V R6 130k LBO OUT C6 10nF R5 33k C2 4.7uF,16V R4 C3 2.2nF GND IOUT GND 1.22 V = R4 Inductor: Falco P/N SDIP0302-156 (305) 622-9076 or Coilcraft P/N DT1608C-153 (847) 639-6400 Figure 1 - Constant Brightness LED driver with 12V compliance from 2-cells (constant current output) VIN = 2V to 5V VOUT = 12V, 75mA D1 SMB5819 L1 15uH U1 R2 1M 6 IN 7 C1 3 1 10uF,6.3V LX LBI FB EN LBO COMP GND SC1417B R6 130k C6 10nF 5 R1 1.00M 2 1uF,16V C2 8 4 R4 115k R5 33k R3 1M LBO OUT C3 2.2nF ENABLE GND GND Figure 2 - Minimum Capacitance Boost Converter Note: (1) Value of C1 depends on proximity of input source voltage and source impedance (use C1 > 47µF if the input supply is greater than two inches from the SC1417B). 2006 Semtech Corp. 9 www.semtech.com SC1417B POWER MANAGEMENT Outline Drawing - MSOP-8 DIMENSIONS INCHES MILLIMETERS DIM MIN NOM MAX MIN NOM MAX e/2 A A A1 A2 b c D E1 E e L L1 N 01 aaa bbb ccc D N 2X E/2 E1 PIN 1 INDICATOR ccc C 2X N/2 TIPS E 1 2 e B aaa C SEATING PLANE D 1.10 0.15 0.00 0.95 0.75 0.38 0.22 0.08 0.23 2.90 3.00 3.10 2.90 3.00 3.10 4.90 BSC 0.65 BSC 0.40 0.60 0.80 (.95) 8 0° 8° 0.10 0.13 0.25 H A2 C .043 .000 .006 .030 .037 .015 .009 .009 .003 .114 .118 .122 .114 .118 .122 .193 BSC .026 BSC .016 .024 .032 (.037) 8 8° 0° .004 .005 .010 A c GAGE PLANE A1 bxN bbb C A-B D 0.25 L (L1) DETAIL SIDE VIEW SEE DETAIL 01 A A NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. DATUMS -A- AND -B- TO BE DETERMINED AT DATUM PLANE -H3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. 4. REFERENCE JEDEC STD MO-187, VARIATION AA. 2006 Semtech Corp. 10 www.semtech.com SC1417B POWER MANAGEMENT Land Pattern - MSOP-8 X DIM (C) G C G P X Y Z Z Y DIMENSIONS INCHES MILLIMETERS (.161) .098 .026 .016 .063 .224 (4.10) 2.50 0.65 0.40 1.60 5.70 P NOTES: 1. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. Contact Information Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805) 498-2111 FAX (805)498-3804 Visit us at: www.semtech.com 2006 Semtech Corp. 11 www.semtech.com