SC250

Step-Down DC-DC Converter with Bias LDO for RF Power Amplifiers POWER MANAGEMENT Description 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. 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. SC250 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 Applications CDMA and WCDMA Phones Handheld Radios RF PC Cards Battery Powered RF Devices Typical Application Circuit VIN CIN 10μF 2 VIN LX VOUT 1 6 L1 4.7μH COUT 4.7μF Vcc ENABLE VDAC 7 5 8 SC250 EN VDAC PGND VREF GND 3 4 CREF 1μ F RF Input BIAS PA GND RF Output August 28, 2006 1 www.semtech.com SC250 POWER MANAGEMENT Absolute Maximum Ratings Parameter Input Supply Voltage EN and VDAC Inputs LX Pin Voltage (Power switch OFF) VOUT Voltage VOUT Short Circuit to GND duration Thermal Impedance Junction to Ambient (1) Operating Ambient Temperature Range Junction Temperature Storage Temperature Peak IR Reflow Temperature ESD Protection Level (2) Symbol VIN VEN, VDAC VLX VOUT tSC θJA TA TJC TS TP VESD Maximum -0.3 to 7 -0.3 to 7 -1 to VIN + 1, 7V MAX -0.3 to 7 Continuous 110 -40 to +85 +150 -60 to +160 260 2 PRELIMINARY 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. Units V V V V s °C/W °C °C °C °C kV 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 VOUT Line Regulation VOUT Load Regulation VREF Accuracy VREF Line Regulation VREF Load Regulation VREF Load Current Peak Inductor Current Bypass FET Current Limit Symbol VIN VOUT VOUT LINE VOUT LOAD VREF VREF LINE VREF LOAD IREF ILX PK IPASS Conditions Min 2.7 Typ Max 5.0 Units V V V %/V % VIN = 4V, VDAC = 0.1V, IOUT = 0.3A VIN = 4V, VDAC = 1.1V, IOUT = 0.3A VIN = 2.7V to 5.0V, VDAC = 0.7V IOUT = 0A to 600 mA, VDAC = 0.7V IREF = 10 mA IREF = 1 mA, IOUT = 0A IREF = 0.1 to 20 mA 0.25 3.23 0.3 3.3 0.35 3.37 0.4 -0.7 2.8 2.85 2.9 0.3 -0.5 20 0.8 1 1.5 2.5 V %/V % mA A A © 2006 Semtech Corp. 2 www.semtech.com SC250 POWER MANAGEMENT Electrical Characteristics (Cont.) Parameter Quiescent Current Shutdown Current VDAC Regulated Output Mode VDAC Pass-Through Mode Threshold VDAC to VOUT Transfer Ratio RDS ON of Bypass P-Channel FET RDS ON of P-Channel Switching FET RDS ON of N-Channel Switching FET LX Leakage Current PMOS LX Leakage Current NMOS VOUT Pin Bypass PMOS Leakage Oscillator Frequency (Fixed Frequency) Oscillator Frequency (Variable Frequency) Logic Input High Logic Input Low Control Input Current - High Control Input Current - Low Enable Transient Over/Undershoot Enable Transient Settling Time VDAC Transient Over/Undershoot VDAC Transient Settling Time © 2006 Semtech Corp. PRELIMINARY Symbol IQ ISD VDAC VDAC PT GV RPASS RDSP RDSN ILXP ILXN ILVOUT fOSC fOSCV VIH VIL IIH IIL OSEN tEN-ST OSVDAC tVDAC-ST Conditions Normal Mode (VDAC < 1V) Bypass Mode (VDAC > 1.4V) LX = open, EN = GND, VOUT = open, TA= 25°C VIN = 4.2V VDAC Rising VDAC Falling Min Typ 1.5 Max Units mA 1 0.1 0.10 1.28 1.20 3 1 1.20 1.37 V 1.3 V/V mΩ mΩ mΩ 2 2 2 0.85 0.65 1.6 0.6 1 1.15 μA μA μA MHz MHz V V μA μA % μs % μs www.semtech.com μA V IOUT = 100mA, VIN = 3V, VDAC= 1.4V IOUT = 100mA, VIN = 3V IOUT = 100mA, VIN = 3V VIN = 3.6V, LX = 0V, EN = GND VIN = 3.6V, LX = 3.6V, EN = GND VIN = 3.6V, VOUT = 0V, EN = GND VDAC > 0.2V VDAC = 0.1V 75 400 250 VDAC/EN =3.6V VDAC/EN = GND 20 40 20 40 ±2 ±2 3 SC250 POWER MANAGEMENT Electrical Characteristics (Cont.) Parameter Pass-Through Transition Over/Undershoot Pass-Through Transition Settling Time Thermal Shutdown Thermal Shutdown Hysteresis Auto Pass-Through Threshold (VIN-VOUT) Auto Pass-Through Threshold Hysteresis Symbol OSPASS tPASS-ST TSD TSDH PTTH PTTH_HYST 400 135 Conditions Min Typ 20 40 160 15 430 160 460 190 PRELIMINARY Max Units % μs °C °C mV mV © 2006 Semtech Corp. 4 www.semtech.com SC250 POWER MANAGEMENT Pin Configuration PRELIMINARY Ordering Information DEVICE LX VIN VREF GND 1 8 PACKAGE PGND EN VOUT VDAC SC250WLTRT(1)(2) MLPD-W8 2.3x2.3 Evaluation Board TOP VIEW 2 3 4 7 6 5 Note: 1) Available on tape and reel only. A reel contains 3000 devices. 2) Device is WEEE and RoHS compliant. Ordering Information SC250EVB 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 POWER MANAGEMENT Block Diagram PRELIMINARY 6 SENSE Current Sense VOUT VIN 2 References 1 LX VREF GND 3 Control Logic 8 4 PWM Comparator PGND EN 7 SENSE VDAC 5 Error Amp. Oscillator Slope Generator © 2006 Semtech Corp. 6 www.semtech.com SC250 POWER MANAGEMENT Pin Descriptions Pin # Pin Name Pin Function PRELIMINARY 1 2 3 4 5 6 7 8 LX VIN VREF GND VDAC VOUT EN PGND Inductor connection to the switching FETs Input voltage connection 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. Ground connection 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. Regulated output voltage and feedback 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 © 2006 Semtech Corp. 7 www.semtech.com SC250 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. 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. Operation Modes The SC250 output voltage is dependent on the VDAC analog control voltage, defined by the following relationship: 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. 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. PRELIMINARY 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. Protection Features The SC250 provides the following protection features: • Thermal shutdown • Current limit • Under-voltage lockout 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. 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.” 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. © 2006 Semtech Corp. 8 www.semtech.com SC250 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. 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: PRELIMINARY 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: fC 2 1 L COUT V OUT 1 IL L V OUT V IN f OSC This single pole filter is designed to operate with an output capacitor value of 4.7μF. 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 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 Manufacturer/Part # BI Technologies HM66304R7 Coilcraft D01608C-472ML TDK VLCF4018T- 4R7N1R0-2 Value (μH) 4.7 DCR (Ω) 0.072 Saturation Current (A) 1.32 Tolerance (%) 20 Dimensions LxWxH (mm) 4.7 × 4.7 ×3.0 VOUT (ESR) IL (ripple ) 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. Table 2 — Recommended Capacitors Manufacturer/Part Number Murata GRM21BR60J226ME39L Murata GRM188R60J106MKE19 TDK C2012X5R0J106K Murata GRM188R60J475KE19D Value (μF) 22 Rated Voltage (VDC) 6.3 Type Case Size X5R 0805 10 6.3 X5R 0603 4.7 0.09 1.5 20 6.6 × 4.5 ×3.0 10 6.3 X5R 0603 4.7 0.101 1.07 30 4.3 × 4.0 ×1.8 4.7 6.3 X5R 0603 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 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. 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. PRELIMINARY 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. LX LOUT COUT VOUT VIN 1 CIN CREF VREF SC250 PGND VDAC EN GND © 2006 Semtech Corp. 10 www.semtech.com SC250 POWER MANAGEMENT Typical Characteristics Efficiency vs. Load Current VOUT = 3.2V 100 90 VIN=3.6V PRELIMINARY Efficiency vs. Load Current VOUT = 2.5V 100 90 VIN=3.3V 80 70 Efficiency (%) VIN=3.9V 80 70 Efficiency (%) 60 50 40 30 20 10 0 0.001 0.01 IOUT (V) 0.1 1 VIN=4.2V 60 50 VIN=3.9V VIN=4.2V 40 30 20 10 0 0.001 0.01 IOUT (V) 0.1 1 Efficiency vs. Load Current VOUT = 1 .5V 100 90 80 70 VIN=3.6V VIN=2.7V Efficiency vs. Load Current VOUT = 1 .2V 100 90 VIN=2.7V 80 70 Efficiency (%) 60 50 40 30 20 10 0 0.001 0.01 IOUT (V) 0.1 1 VIN=4.2V Efficiency (%) 60 50 40 30 20 10 0 0.001 VIN=3.6V VIN=4.2V 0.01 IOUT (V) 0.1 1 Efficiency vs. VIN 100 90 80 IOUT=300mA IOUT=600mA IOUT=100mA Efficiency vs. VOUT, VIN = 3.6V 100 90 80 70 IOUT=100mA IOUT=600mA 70 Efficiency (%) Efficiency(%) 60 50 IOUT=10mA 60 50 40 30 20 10 0 0 0.5 1 1.5 VIN (V) 2 2.5 3 3.5 40 30 20 10 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. 11 www.semtech.com SC250 POWER MANAGEMENT Typical Characteristics (Cont.) Control Transfer Function IOUT = 0.3A 6.0 4.1 3.9 VIN=5.5V VIN=4.2V PRELIMINARY Auto Bypass Function, VOUT = 3.25V 5.0 3.7 VIN Up 4.0 3.5 VIN=3.6V VIN=3.0V VIN=2.7V ` VOUT (V) 3.0 VOUT (V) 3.3 3.1 2.9 VIN Down 2.0 1.0 0.0 0 0.2 0.4 0.6 0.8 VDAC (V) 1 1.2 1.4 1.6 2.7 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) Dynamic Supply Current vs. VIN 0.006 VOUT=2.1V Shutdown Current vs. Temperature, VIN = 3.6V 16 14 12 0.005 VOUT=1.5V IQ Shutdown (μA) 0.004 10 8 6 4 IIN (A) 0.003 VOUT=0.3V 0.002 0.001 0 2.5 3 3.5 4 VIN (V) 4.5 5 5.5 6 2 0 -40 -20 0 20 40 TJ (°C) 60 80 100 120 Load Regulation, VOUT = 2.1V 2.2 1.52 Line Regulation, VOUT = 1 .5V 150mA 1.515 2.15 1.51 VOUT (V) 50mA 2.1 VOUT (V) 1.505 600mA 300mA 1.5 2.05 1.495 1.49 2.5 2 0 0.2 0.4 0.6 0.8 IOUT (A) 1 1.2 1.4 1.6 3 3.5 4 4.5 TA (°C) 5 5.5 6 © 2006 Semtech Corp. 12 www.semtech.com SC250 POWER MANAGEMENT Typical Characteristics (Cont.) VOUT vs. Temperature (VOUT = 1 .5V) 1.56 PRELIMINARY VOUT vs. Temperature (VOUT = 3.2V) 3.26 1.54 3.24 IOUT=10mA VOUT (V) 1.5 IOUT=10mA IOUT=300mA IOUT=600mA VOUT (V) 1.52 IOUT=100mA 3.22 3.2 IOUT=100mA IOUT=300mA IOUT=600mA 1.48 3.18 1.46 -60 -40 -20 0 20 TA (°C) 40 60 80 100 3.16 -60 -40 -20 0 20 40 60 80 100 TA (°C) VREF vs. VIN 2.9 2.865 VREF vs. IREF 2.85 2.86 2.8 VREF (V) 2.855 2.75 VREF (V) 2.85 2.7 2.845 2.65 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) 2.84 2.835 0 0.005 0.01 IREF (A) 0.015 0.02 0.025 Maximum Output Current, VOUT = 2.5V 3 2 1.8 Maximum Output Current, VOUT = 1 .8V 2.5 VIN=5.0V VIN=4.0V 1.6 VIN=5.0V VIN=4.0V 2 VOUT (V) 1.4 1.5 VOUT (V) VIN=4.5V VIN=3.5V 1.2 1 VIN=4.5V VIN=3.5V 0.8 0.6 0.4 0.2 1 0.5 0 1 1.1 1.2 1.3 IOUT (A) 1.4 1.5 1.6 0 1 1.1 1.2 1.3 IOUT (A) 1.4 1.5 1.6 © 2006 Semtech Corp. 13 www.semtech.com SC250 POWER MANAGEMENT Typical Characteristics (Cont.) Maximum Output Current, VOUT = 1 .5V 1.6 1.4 VIN=5.0V VIN=2.7V VIN=3.0V PRELIMINARY Dropout Voltage vs. Bypass Load Current 50 45 40 1 Dropout Voltage (mV) 1.2 35 30 25 20 15 10 VOUT (V) 0.8 VIN=4.5V 0.6 VIN=3.5V 0.4 0.2 0 1 1.1 1.2 1.3 IOUT (A) 1.4 1.5 1.6 VIN=4.0V 5 0 0 0.1 0.2 0.3 0.4 IOUT (A) 0.5 0.6 0.7 PMOS Current Limit vs. Temperature 1280 1260 PMOS Current Limit (mA) 1700 Passthrough Current Limit vs. Temperature 1240 1220 1200 1180 1160 1140 1120 -40 Passthrough Current Limit (mA) 1650 1600 1550 1500 1450 -20 0 20 40 60 80 100 120 1400 -40 -20 0 20 40 60 80 100 120 TJ (°C) TJ (°C) Oscillator Frequency vs. VDAC, VIN = 3.6V 1100 1050 1000 Oscillator Frequency vs. Temperature, VIN = 3.6V 1080 1060 Switching Frequency (kHz) Oscillator Frequency (kHz) 950 900 850 800 750 700 650 600 550 500 0 0.1 0.2 0.3 0.4 0.5 0.6 VDAC(V) 0.7 0.8 0.9 1 1.1 1040 1020 1000 980 960 940 -40 -20 0 20 40 60 TJ (°C) 80 100 120 140 © 2006 Semtech Corp. 14 www.semtech.com SC250 POWER MANAGEMENT Typical Characteristics (Cont.) RDSON vs. Temperature, VIN = 3.6V 450 400 PMOS PRELIMINARY RDSON vs. VIN 400 350 PMOS 350 RDSON (mΩ) 300 NMOS NMOS 300 250 200 150 100 50 0 -45 5 250 RDSON (mΩ) PASS 200 150 100 PASS 50 0 2.5 55 TJ (°C) 105 155 3.0 3.5 4.0 VIN(V) 4.5 5.0 5.5 VDAC Step Response (Pass-through) VOUT (1V/div) VDAC Step Response (100% duty) 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) Time (40μs/div) Condition VIN=4.2V, Load=15Ω, VDAC=0.5 to 1.1V Time (40μs/div) Condition VIN=3.6V, Load=15Ω, VDAC=0.7V VEN (2V/div) © 2006 Semtech Corp. 15 www.semtech.com SC250 POWER MANAGEMENT Typical Characteristics (Cont.) Load Step response (VOUT=3.25V) PRELIMINARY Load Step response (VOUT=1.5V) VOUT (100mV/div) VOUT (100mV/div) IOUT(500mA/div) IOUT(500mA/div) Time (40μs/div) Condition VIN=4.2V, Load=600mA-60mA, VOUT=3.25V Time (40μs/div) Condition VIN=3.6V, Load=600mA-60mA, VOUT=1.5V Enable Start-Up VEN (2V/div) VOUT (1V/div) VLX (5V/div) Output Ripple Waveform (VOUT=3.25V) VOUT (50mV/div) VLX(5V/div) IIN (500mA/div) Time (1μs/div) Condition VIN=4.2V, Load=300mA, VOUT=3.25V Time (20μs/div) Condition VIN=4.2V, Load=15Ω, VOUT=3.4V Output Ripple Waveform (VOUT=1.5V) Pass-Through Current Limit VOUT (50mV/div) VLX(5V/div) VOUT (1V/div) VLX(2V/div) Time (1μs/div) Condition VIN=3.6V, Load=300mA, VOUT=1.5V Time (1ms/div) Condition VIN=3.6V, Load=1Ω, VDAC=1.4V © 2006 Semtech Corp. 16 www.semtech.com SC250 POWER MANAGEMENT Outline Drawing - MLPD-W8, 2.3 x 2.3 PRELIMINARY Marking Information © 2006 Semtech Corp. 17 www.semtech.com SC250 POWER MANAGEMENT Land Pattern - MLPD-W8, 2.3 x 2.3 PRELIMINARY 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