SC250 Step-Down DC-DC Converter with Bias LDO for RF Power Amplifiers POWER MANAGEMENT Description Features Adjustable output voltage range — 0.3 to 3.6V Linearly proportional VDAC to VOUT relationship for increased PA efficiency Pass-through mode automatic and on demand Input voltage range — 2.7V to 5V Typical settling time — 40μs Output current capability — 600mA Maximum output current in bypass mode — 1A Up to 96% efficiency Constant frequency operation — 1MHz Less than 1μA shutdown current Internal 75mΩ PMOS bypass transistor PA bias voltage supply — 2.85V, 20mA, 1.5% MLPD-W8, 2.3 x 2.3mm package The SC250 is a synchronous step-down converter designed specifically for use as an adaptive voltage supply for CDMA and WCDMA RF Power Amplifiers (PAs). The output voltage can be adjusted dynamically between 0.3V and (Vin - 0.4)V through a linear analog control input. For high power operation, a maximum control input signal level forces the device into bypass mode where the input is connected directly to the output via an internal PChannel pass transistor. Bypass mode also occurs when the output load demands duty cycles in excess of the maximum rated duty cycle. The SC250 also provides an LDO regulator which can be used to supply a 2.85V bias to the PA. The internal clock runs at 1MHz to maximize efficiency while still allowing the use of small surface mount inductors and capacitors can be used. Applications The peak current rating of the internal PMOS switch allows a DC output current of 600mA. The bypass PMOS current rating allows a minimum of 1A DC output current in the bypass mode. Shutdown turns off all the control circuitry to achieve a typical shutdown current of 0.1μA. CDMA and WCDMA Phones Handheld Radios RF PC Cards Battery Powered RF Devices Typical Application Circuit 2 VIN LX VIN CIN 10μF ENABLE VDAC VOUT 7 5 8 August 28, 2006 1 L1 4.7μH COUT 4.7μF 6 Vcc SC250 PA EN VDAC PGND VREF GND RF Input 3 4 BIAS RF Output GND CREF 1μF 1 www.semtech.com SC250 PRELIMINARY 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 recommended. Parameter Symbol Maximum Units Input Supply Voltage VIN -0.3 to 7 V EN and VDAC Inputs VEN, VDAC -0.3 to 7 V LX Pin Voltage (Power switch OFF) VLX -1 to VIN + 1, 7V MAX V VOUT Voltage VOUT -0.3 to 7 V VOUT Short Circuit to GND duration tSC Continuous s Thermal Impedance Junction to Ambient (1) θJA 110 °C/W Operating Ambient Temperature Range TA -40 to +85 °C Junction Temperature TJC +150 °C Storage Temperature TS -60 to +160 °C Peak IR Reflow Temperature TP 260 °C VESD 2 kV ESD Protection Level (2) Note: 1) Calculated from package in still air, mounted to 3” x 4.5”, 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards. 2) Tested according to JEDEC standard JESD22-A114-B. Electrical Characteristics Unless otherwise noted: VIN = VEN =3.6V, TA = -40 to 85°C. Typical values are at TA = +25°C. Parameter Input Voltage Range VOUT Accuracy Symbol Conditions VIN VOUT V VIN = 4V, VDAC = 1.1V, IOUT = 0.3A 3.23 3.3 3.37 V 0.4 %/V IOUT = 0A to 600 mA, VDAC = 0.7V VREF IREF = 10 mA VREF Line Regulation VREF LINE IREF = 1 mA, IOUT = 0A VREF Load Regulation VREF LOAD IREF = 0.1 to 20 mA Bypass FET Current Limit IPASS © 2006 Semtech Corp. V 0.35 VOUT LOAD ILX PK 5.0 0.3 VOUT Load Regulation Peak Inductor Current Units 0.25 VIN = 2.7V to 5.0V, VDAC = 0.7V IREF Max VIN = 4V, VDAC = 0.1V, IOUT = 0.3A VOUT LINE VREF Load Current Typ 2.7 VOUT Line Regulation VREF Accuracy Min 2 -0.7 2.8 2.85 % 2.9 V 0.3 %/V -0.5 % 20 mA 0.8 1.5 A 1 2.5 A www.semtech.com SC250 PRELIMINARY POWER MANAGEMENT Electrical Characteristics (Cont.) Parameter Quiescent Current Shutdown Current VDAC Regulated Output Mode VDAC Pass-Through Mode Threshold VDAC to VOUT Transfer Ratio Symbol Conditions Min Typ Normal Mode (VDAC < 1V) 1.5 Bypass Mode (VDAC > 1.4V) 1 ISD LX = open, EN = GND, VOUT = open, TA= 25°C 0.1 VDAC VIN = 4.2V IQ VDAC PT Max Units mA 1 μA 0.10 1.20 V VDAC Rising 1.28 1.37 VDAC Falling 1.20 1.3 V GV 3 V/V RDS ON of Bypass P-Channel FET RPASS IOUT = 100mA, VIN = 3V, VDAC= 1.4V 75 mΩ RDS ON of P-Channel Switching FET RDSP IOUT = 100mA, VIN = 3V 400 mΩ RDS ON of N-Channel Switching FET RDSN IOUT = 100mA, VIN = 3V 250 mΩ LX Leakage Current PMOS ILXP VIN = 3.6V, LX = 0V, EN = GND 2 μA LX Leakage Current NMOS ILXN VIN = 3.6V, LX = 3.6V, EN = GND 2 μA ILVOUT VIN = 3.6V, VOUT = 0V, EN = GND 2 μA Oscillator Frequency (Fixed Frequency) fOSC VDAC > 0.2V 0.85 1.15 MHz Oscillator Frequency (Variable Frequency) fOSCV VDAC = 0.1V 0.65 MHz 1.6 V VOUT Pin Bypass PMOS Leakage Logic Input High VIH Logic Input Low VIL Control Input Current - High IIH Control Input Current - Low IIL 1 0.6 V VDAC/EN =3.6V ±2 μA VDAC/EN = GND ±2 μA Enable Transient Over/Undershoot OSEN 20 % Enable Transient Settling Time tEN-ST 40 μs VDAC Transient Over/Undershoot OSVDAC 20 % VDAC Transient Settling Time tVDAC-ST 40 μs © 2006 Semtech Corp. 3 www.semtech.com SC250 PRELIMINARY POWER MANAGEMENT Electrical Characteristics (Cont.) Parameter Symbol Conditions Min Typ Max Units Pass-Through Transition Over/Undershoot OSPASS 20 % Pass-Through Transition Settling Time tPASS-ST 40 μs Thermal Shutdown TSD 160 °C Thermal Shutdown Hysteresis TSDH 15 °C Auto Pass-Through Threshold (VIN-VOUT) PTTH 400 430 460 mV Auto Pass-Through Threshold Hysteresis PTTH_HYST 135 160 190 mV © 2006 Semtech Corp. 4 www.semtech.com SC250 PRELIMINARY POWER MANAGEMENT Pin Configuration LX 1 Ordering Information 8 PGND TOP VIEW VIN 2 7 EN VREF 3 6 VOUT GND 4 5 VDAC DEVICE PACKAGE SC250WLTRT(1)(2) MLPD-W8 2.3x2.3 SC250EVB Evaluation Board Ordering Information Note: 1) Available on tape and reel only. A reel contains 3000 devices. 2) Device is WEEE and RoHS compliant. MLPD-W8 2.3 x 2.3 Marking Information 250 yw Marking for the 2.3 x 2.3mm MLPD 8 Lead Package: ww = Datecode (Reference Package Marking Design Guidelines, Appendix A) © 2006 Semtech Corp. 5 www.semtech.com SC250 PRELIMINARY POWER MANAGEMENT Block Diagram 6 VOUT 1 LX 8 PGND SENSE Current Sense VIN 2 References VREF 3 GND 4 Control Logic PWM Comparator EN 7 SENSE VDAC 5 Error Amp. Oscillator © 2006 Semtech Corp. Slope Generator 6 www.semtech.com SC250 PRELIMINARY POWER MANAGEMENT Pin Descriptions Pin # Pin Name 1 LX Inductor connection to the switching FETs 2 VIN Input voltage connection 3 VREF 2.85V, 20mA reference supply — can be used as a supply for power amplifier bias inputs or to supply a resistive divider on VDAC to set a fixed level of VOUT. 4 GND Ground connection 5 VDAC Analog control voltage input ranges between 0.1 and 1.2V for control of VOUT in accordance with the VOUT= 3 x VDAC transfer function. VDAC > 1.4V enables pass-through mode using the internal pass MOSFET. 6 VOUT Regulated output voltage and feedback 7 EN 8 PGND © 2006 Semtech Corp. Pin Function Enable digital input: a high input enables the SC250, a low disables the output and reduces quiescent current to less than 1μA and LX becomes high impedance. Ground reference for internal N-channel MOSFET 7 www.semtech.com SC250 PRELIMINARY POWER MANAGEMENT Applications Information SC250 Detailed Description The SC250 adaptive power controller is a step-down, fixed frequency pulse-width modulated DC-DC converter designed for use with RF Power Amplifiers (PAs) in CDMA and WCDMA handsets and modules. The SC250 output is used to supply DC power to the PA rather than connecting the DC input pin directly to the battery supply. A substantial system power efficiency improvement can be achieved by allowing the system controller to adaptively adjust the DC power to the PA, reducing the total power consumption of the device when in low-power mode. To improve efficiency at all RF output gain settings, the PA supply voltage is adjusted in a linear fashion, minimizing PA supply headroom and losses. Bias Supply Output In addition to the main output, the SC250 also provides a low current LDO output that can be used as a bias supply for power amplifiers. This output provides a regulated 2.85V with output current capability up to 20mA. The 2.85V output is guaranteed for input supply voltages in excess of 2.95V. A consequence of using the SC250 to power the PA, rather than using a linear regulator or direct connection to the battery, is that less current is needed. Reduced current consumption results in more talk-time for the handset. Thermal Shutdown The device has a thermal shutdown feature to protect the device if the junction temperature exceeds 150°C. In thermal shutdown, the PWM drive is disabled, effectively tri-stating the LX output. The device will not be enabled again until the temperature reduces by 10°C. Protection Features The SC250 provides the following protection features: • Thermal shutdown • Current limit • Under-voltage lockout Operation Modes The SC250 output voltage is dependent on the VDAC analog control voltage, defined by the following relationship: Short-Circuit Protection The PMOS and NMOS power devices of the buck switcher stage are protected by current limit functions. In the case of a short to ground on the output, the LX pin will switch with minimum duty cycle. The duty cycle is short enough to allow the inductor to discharge during each cycle, thereby preventing the inductor current from “staircasing.” VOUT = 3 × VDAC In a typical PA system application, the system controller determines what output power level is needed from the PA and adjusts the VDAC voltage to match the required PA headroom for optimized efficiency. The pass-through PMOS is also protected by a current limit function. When the part is first enabled in passthrough, the output capacitor charges up with a large surge current. This surge current is internally limited for protection purposes, but the limit is set high enough to meet fast start-up times. In order to protect against a short-circuit condition and to allow the transient response time, an internal timer allows the part to operate under current limit conditions for a maximum of 64 cycles of the internal clock (1MHz typical). If the short-circuit conditions persists, the pass-through PMOS will turn off for 1ms, after which the first timer is restarted. This allows the part to manage thermal dissipation while giving it the ability to recover when the fault condition is removed. Pass-Through Mode When the VDAC voltage reaches 1.36V, the SC250 enters pass-through mode. If the demanded output voltage is within 430mV of the input voltage, the SC250 automatically enters pass-through as this exceeds the maximum controlled duty cycle of the power converter. In pass-through mode, the device enables an internal PChannel MOSFET that bypasses the converter, connecting the output directly to the input. The RDSON of this FET is extremely low, so there is little voltage drop across the part. Pass-through allows the lowest insertion loss possible between VIN and VOUT under high-power conditions, thereby maintaining maximum efficiency under these conditions. © 2006 Semtech Corp. 8 www.semtech.com SC250 PRELIMINARY POWER MANAGEMENT Applications Information (Cont.) Under-Voltage Lockout Under-voltage lockout protection is used to prevent erroneous operation. As the input decreases, the device shuts down when the voltage drops below 2.35V and will not restart until the input voltage exceeds approximately 2.5V. ESR ceramic capacitor is required. A minimum value of 10μF should be used for sufficient input voltage filtering and a 22μF should be used for improved input voltage filtering. COUT Selection The internal compensation is designed to work with a certain output filter corner frequency defined by the equation: Inductor Selection The SC250 is designed for use with a 4.7μH inductor. The magnitude of the inductor current ripple is dependent on the inductor value and can be determined by the following equation: fC This single pole filter is designed to operate with an output capacitor value of 4.7μF. V OUT · V OUT §¨ 1 ¸ V IN ¹ © L u f OSC ' IL 1 2S L u COUT Output voltage ripple is a combination of the voltage ripple from the inductor current charging and discharging the output capacitor, and the voltage created from the inductor current ripple through the output capacitor ESR. Selecting an output capacitor with a low ESR will reduce the output voltage ripple component that is dependent upon this ESR, as can be seen in the following equation: This equation demonstrates the relationship between input voltage, output voltage, and inductor ripple current. The inductor should have a low DC resistance to minimize the conduction losses and maximize efficiency. As a minimum requirement, the DC current rating of the inductor should be equal to the maximum load current plus half of the inductor current ripple as shown by the following equation: 'IL ILPK IOUT (MAX ) 2 'VOUT (ESR) 'IL (ripple ) u ESR( COUT ) Capacitors with X7R or X5R ceramic dielectric are strongly recommended for their low ESR and superior temperature and voltage characteristics. Y5V capacitors should not be used as their temperature coefficients make them unsuitable for this application. Table 2 lists the manufacturers of recommended capacitor options. Final inductor selection depends on various design considerations such as efficiency, EMI, size, and cost. Table 1 lists the manufacturers of practical inductor options. Table 1 — Recommended Inductors Table 2 — Recommended Capacitors Value (μF) Rated Voltage (VDC) Type Case Size Murata GRM21BR60J226ME39L 22 6.3 X5R 0805 Manufacturer/Part Number Value (μH) DCR (Ω) Saturation Current (A) Tolerance (%) Dimensions LxWxH (mm) BI Technologies HM66304R7 4.7 0.072 1.32 20 4.7 × 4.7 ×3.0 Murata GRM188R60J106MKE19 10 6.3 X5R 0603 Coilcraft D01608C-472ML 4.7 0.09 1.5 20 6.6 × 4.5 ×3.0 TDK C2012X5R0J106K 10 6.3 X5R 0603 TDK VLCF4018T- 4R7N1R0-2 4.7 0.101 1.07 30 4.3 × 4.0 ×1.8 Murata GRM188R60J475KE19D 4.7 6.3 X5R 0603 Manufacturer/Part # CIN Selection The source input current to a buck converter is noncontinuous. To prevent large input voltage ripple, a low © 2006 Semtech Corp. 9 www.semtech.com SC250 PRELIMINARY POWER MANAGEMENT Applications Information (Cont.) PCB Layout Considerations Poor layout can degrade the performance of the DCDC converter and can be a contributory factor in EMI problems, ground bounce and resistive voltage losses. Poor regulation and instability can result. 3. Maximize ground metal on component side to improve the return connection and thermal dissipation. Separation between the LX node and GND should be maintained to avoid coupling of switching noise to the ground plane. 4. To further reduce noise interference on sensitive circuit nodes, use a ground plane with several vias connecting to the component side ground. A few simple design rules can be implemented to ensure good layout: 1. Place the inductor and filter capacitors as close to the device as possible and use short wide traces between the power components. 2. Route the output voltage feedback and VDAC path away from inductor and LX node to minimize noise and magnetic interference. LX LOUT VOUT COUT VIN VREF 1 SC250 CIN CREF PGND VDAC EN GND © 2006 Semtech Corp. 10 www.semtech.com SC250 PRELIMINARY POWER MANAGEMENT Typical Characteristics Efficiency vs. Load Current VOUT = 3.2V Efficiency vs. Load Current VOUT = 2.5V 100 100 90 90 VIN=3.6V VIN=3.3V 80 80 70 VIN=3.9V Efficiency (%) Efficiency (%) 70 60 50 VIN=4.2V 40 60 50 VIN=4.2V 40 30 30 20 20 10 10 0 0.001 0.01 0.1 0 0.001 1 IOUT (V) 0.01 0.1 Efficiency vs. Load Current VOUT = 1.2V 100 100 90 90 VIN=2.7V VIN=2.7V 80 80 70 70 Efficiency (%) VIN=3.6V 60 50 VIN=4.2V 40 50 30 20 10 10 0 0.001 1 0.1 VIN=4.2V 40 20 0.01 VIN=3.6V 60 30 0 0.001 0.01 0.1 Efficiency vs. VIN Efficiency vs. VOUT, VIN = 3.6V 100 100 90 90 80 80 IOUT=600mA 70 IOUT=100mA 60 50 IOUT=10mA 40 IOUT=600mA 60 50 40 30 30 20 20 10 10 0 0 2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5 VIN (V) © 2006 Semtech Corp. IOUT=100mA 70 Efficiency(%) IOUT=300mA 1 IOUT (V) IOUT (V) Efficiency (%) 1 IOUT (V) Efficiency vs. Load Current VOUT = 1.5V Efficiency (%) VIN=3.9V 0 0.5 1 1.5 2 2.5 3 3.5 VIN (V) 11 www.semtech.com SC250 PRELIMINARY POWER MANAGEMENT Typical Characteristics (Cont.) Auto Bypass Function, VOUT = 3.25V Control Transfer Function IOUT = 0.3A 6.0 4.1 3.9 5.0 VIN=5.5V VIN Up 3.5 VOUT (V) VOUT (V) 3.7 VIN=4.2V 4.0 VIN=3.6V 3.0 VIN=3.0V ` VIN Down 3.1 VIN=2.7V 2.0 3.3 2.9 1.0 2.7 0.0 0 0.2 0.4 0.6 0.8 VDAC (V) 1 1.2 1.4 2.5 2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5 VIN(V) 1.6 Shutdown Current vs. Temperature, VIN = 3.6V Dynamic Supply Current vs. VIN 16 0.006 VOUT=2.1V 14 VOUT=1.5V 12 0.005 IQ Shutdown (μA) IIN (A) 0.004 0.003 VOUT=0.3V 0.002 10 8 6 4 0.001 2 0 2.5 3 3.5 4 4.5 5 5.5 0 -40 6 -20 0 20 40 60 80 100 120 TJ (°C) VIN (V) Load Regulation, VOUT = 2.1V Line Regulation, VOUT = 1.5V 2.2 1.52 150mA 1.515 2.15 50mA VOUT (V) VOUT (V) 1.51 2.1 1.505 600mA 1.5 300mA 2.05 1.495 1.49 2.5 2 0 0.2 0.4 © 2006 Semtech Corp. 0.6 0.8 IOUT (A) 1 1.2 1.4 1.6 3 3.5 4 4.5 5 5.5 6 TA (°C) 12 www.semtech.com SC250 PRELIMINARY POWER MANAGEMENT Typical Characteristics (Cont.) VOUT vs. Temperature (VOUT = 3.2V) VOUT vs. Temperature (VOUT = 1.5V) 1.56 3.26 1.54 3.24 IOUT=10mA IOUT=100mA 3.22 VOUT (V) VOUT (V) 1.52 1.5 IOUT=10mA 3.2 IOUT=100mA IOUT=600mA IOUT=300mA -40 -20 0 20 TA (°C) 40 60 80 3.16 -60 100 -40 -20 0 20 60 40 80 100 TA (°C) VREF vs. VIN VREF vs. IREF 2.9 2.865 2.85 2.86 2.8 2.855 VREF (V) VREF (V) IOUT=600mA 3.18 1.48 1.46 -60 IOUT=300mA 2.75 2.85 2.7 2.845 2.65 2.84 2.6 2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5 VIN (V) 2.835 0 0.005 0.01 0.015 0.02 0.025 IREF (A) Maximum Output Current, VOUT = 2.5V Maximum Output Current, VOUT = 1.8V 3 2 1.8 2.5 1.6 VIN=4.0V VIN=5.0V VIN=5.0V VIN=4.5V VIN=3.5V VOUT (V) VOUT (V) VIN=4.0V 1.4 2 1.5 1 1.2 VIN=3.5V 1 VIN=4.5V 0.8 0.6 0.4 0.5 0.2 0 0 1 1.1 1.2 1.3 1.4 1.5 1.6 1 IOUT (A) © 2006 Semtech Corp. 13 1.1 1.2 1.3 IOUT (A) 1.4 1.5 1.6 www.semtech.com SC250 PRELIMINARY POWER MANAGEMENT Typical Characteristics (Cont.) Dropout Voltage vs. Bypass Load Current Maximum Output Current, VOUT = 1.5V 50 1.6 45 1.4 VIN=5.0V 40 VIN=2.7V Dropout Voltage (mV) 1.2 VIN=3.0V VOUT (V) 1 0.8 VIN=4.5V 0.6 VIN=3.5V 0.4 30 25 20 15 10 VIN=4.0V 0.2 5 0 0 1 1.1 1.2 1.3 1.4 1.5 0 1.6 0.2 0.3 0.4 0.5 0.6 0.7 IOUT (A) PMOS Current Limit vs. Temperature Passthrough Current Limit vs. Temperature 1700 1260 1650 Passthrough Current Limit (mA) 1240 1220 1200 1180 1160 1600 1550 1500 1450 1140 1120 -40 0.1 IOUT (A) 1280 PMOS Current Limit (mA) 35 -20 0 20 40 60 80 100 1400 -40 120 -20 0 20 TJ (°C) 40 60 80 100 120 TJ (°C) Oscillator Frequency vs. Temperature, VIN = 3.6V Oscillator Frequency vs. VDAC, VIN = 3.6V 1100 1080 1050 1060 950 Oscillator Frequency (kHz) Switching Frequency (kHz) 1000 900 850 800 750 700 650 600 1040 1020 1000 980 960 550 500 0 0.1 0.2 © 2006 Semtech Corp. 0.3 0.4 0.5 0.6 VDAC(V) 0.7 0.8 0.9 1 940 -40 1.1 14 -20 0 20 40 60 TJ (°C) 80 100 120 140 www.semtech.com SC250 PRELIMINARY POWER MANAGEMENT Typical Characteristics (Cont.) RDSON vs. VIN RDSON vs. Temperature, VIN = 3.6V 400 450 400 350 PMOS PMOS 300 NMOS 300 NMOS 250 RDSON (mΩ) RDSON (mΩ) 350 250 200 200 150 150 100 100 PASS PASS 50 50 0 -45 5 55 105 0 2.5 155 3.0 3.5 4.0 4.5 5.0 5.5 VIN(V) TJ (°C) VDAC Step Response (100% duty) VDAC Step Response (Pass-through) VOUT (1V/div) VOUT (1V/div) VDAC (1V/div) VDAC (500mV/div) VLX (2V/div) VLX (2V/div) Time (40μs/div) Condition VIN=3.6V, Load=15Ω, VDAC=0.7 to 1.7V Time (40μs/div) Condition VIN=3V, Load=15Ω, VDAC=0.7 to 1V VDAC Step Response Enable Transient VOUT (1V/div) VOUT (1V/div) VDAC (500mV/div) VLX (2V/div) VLX (2V/div) VEN (2V/div) Time (40μs/div) Condition VIN=3.6V, Load=15Ω, VDAC=0.7V Time (40μs/div) Condition VIN=4.2V, Load=15Ω, VDAC=0.5 to 1.1V © 2006 Semtech Corp. 15 www.semtech.com SC250 PRELIMINARY POWER MANAGEMENT Typical Characteristics (Cont.) Load Step response (VOUT=3.25V) Load Step response (VOUT=1.5V) VOUT (100mV/div) VOUT (100mV/div) IOUT(500mA/div) IOUT(500mA/div) Time (40μs/div) Condition VIN=3.6V, Load=600mA-60mA, VOUT=1.5V Time (40μs/div) Condition VIN=4.2V, Load=600mA-60mA, VOUT=3.25V Enable Start-Up Output Ripple Waveform (VOUT=3.25V) VEN (2V/div) VOUT (1V/div) VOUT (50mV/div) VLX (5V/div) VLX(5V/div) IIN (500mA/div) Time (20μs/div) Condition VIN=4.2V, Load=15Ω, VOUT=3.4V Time (1μs/div) Condition VIN=4.2V, Load=300mA, VOUT=3.25V Output Ripple Waveform (VOUT=1.5V) Pass-Through Current Limit VOUT (1V/div) VOUT (50mV/div) VLX(5V/div) VLX(2V/div) Time (1ms/div) Condition VIN=3.6V, Load=1Ω, VDAC=1.4V Time (1μs/div) Condition VIN=3.6V, Load=300mA, VOUT=1.5V © 2006 Semtech Corp. 16 www.semtech.com SC250 PRELIMINARY POWER MANAGEMENT Outline Drawing - MLPD-W8, 2.3 x 2.3 Marking Information © 2006 Semtech Corp. 17 www.semtech.com SC250 PRELIMINARY POWER MANAGEMENT Land Pattern - MLPD-W8, 2.3 x 2.3 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 © 2006 Semtech Corp. 18 www.semtech.com