GERAL DESCRIPTION The SGM0 is a constant frequency, current mode, synchronous step-up switching regulator. Its output currents can go as high as 7mA while using a single-cell alkaline, and discharge it down to 0.9V. It can also be used for generating V at 00mA from a.v rail or a Li-Ion battery. High switching frequency minimizes the sizes of inductor and capacitor. Integrated power MOSFETs and internal compensation make the SGM0 simple to use and fit the total solution into a compact space. For light load current, the SGM0 enters into the power-save mode to maintain high efficiency. Anti-ringing control circuitry reduces EMI concerns by damping the inductor in discontinuous mode. The SGM0 provides true output disconnect and this allows to go to zero volt during shutdown without drawing any current from the input source. The output voltage of SGM0-ADJ can be programmed by an external resistor divider, and those of SGM0-./SGM0-.0 are fixed internally on the chip. The device is available in SOT-- package. It operates over an ambient temperature range of -0 to +8. FEATURES Boost Converter Device Quiescent Current: 0µA (TYP) Less than μa Shutdown Current Input Voltage Range: 0.9V to.v.v and.0v Fixed Output Voltages Adjustable Output Voltage Up to.v Output Voltage Clamping: V Power-Save Mode for Improved Efficiency at Low Output Power Load Disconnect During Shutdown Over-Temperature Protection Available in Green SOT-- Package -0 to +8 Operating Temperature Range APPLICATIONS Single-Cell Li Battery Powered Products Portable Audio Players Cellular Phones Personal Medical Products TYPICAL APPLICATION Power Supply C L.7μH SGM0 FB R R C Output voltage can be adjusted Figure. Typical Application Circuit REV. A.
PACKAGE/ORDERING INFORMATION MODEL SGM0 (V) PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE ORDERING NUMBER PACKAGE MARKING PACKING OPTION Adjustable SOT-- -0 to +8 SGM0-ADJYNG/TR SC8XX Tape and Reel, 000. SOT-- -0 to +8 SGM0-.YNG/TR SC9XX Tape and Reel, 000 NOTE: XX = Date Code..0 SOT-- -0 to +8 SGM0-.0YNG/TR SCAXX Tape and Reel, 000 Green (RoHS & HSF): defines "Green" to mean Pb-Free (RoHS compatible) and free of halogen substances. If you have additional comments or questions, please contact your SGMICRO representative directly. MARKING INFORMATION SYY X X Date code - Month ("A" = Jan. "B" = Feb. "L" = Dec.) Date code - Year ("A" = 00, "B" = 0 ) Chip I.D. For example: SC8CA (0, January) ABSOLUTE MAXIMUM RATINGS Input Voltage Range on,,, FB,... -0.V to V Package Thermal Resistance SOT--, θ JA... 0 /W Junction Temperature... +0 Storage Temperature Range... - to +0 Lead Temperature (Soldering, 0s)... +0 ESD Susceptibility HBM... 000V MM... 0V RECOMMDED OPERATING CONDITIONS Operating Temperature Range... -0 to +8 OVERSTRESS CAUTION Stresses beyond those listed may cause permanent damage to the device. Functional operation of the device at these or any other conditions beyond those indicated in the operational section of the specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability. ESD SSITIVITY CAUTION This integrated circuit can be damaged by ESD if you don t pay attention to ESD protection. SGMICRO recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. DISCLAIMER reserves the right to make any change in circuit design, specification or other related things if necessary without notice at any time.
PIN CONFIGURATION (TOP VIEW) NC/FB SOT-- PIN DESCRIPTION PIN NAME FUNCTION Boost and Rectifying Switch Input. Ground. Enable Input. (/ enabled, 0/ disabled) NC FB No Connect. It should be left floating. (SGM0-./SGM0-.0) Output Voltage Feedback Pin. Voltage feedback for programming the output voltage. (SGM0-ADJ) Boost Converter Output. Boost Converter Supply Voltage.
ELECTRICAL CHARACTERISTICS (Full = -0 to +8, typical values are at T A = +, unless otherwise noted.) DC/DC STAGE PARAMETER SYMBOL CONDITIONS TEMP MIN TYP MAX UNITS Output Voltage Range Full.. V Minimum Input Voltage Range for Start-Up V IN R L =.kω Full 0.9. R L = 70Ω Full.. Input Voltage Range after Start-Up V IN + 0.9. Feedback Voltage V FB Full 8 00 9 mv Oscillator Frequency f Full 870 00 70 khz Switch Current Limit I Full 0.7.. A Start-Up Current Limit + 00 ma Boost Switch-On Resistance =.V + 80 mω Rectifying Switch-On Resistance =.V + 00 mω Output Voltage Accuracy V CC =.V, I O = 0mA Full.8 % Line Regulation V CC = 0.9V to - 0.V, I O = 0mA Full 0. % Load Regulation + 0. % Quiescent Current V CC V = V CC =.V, I O = 0mA Full 0. µa =.V + 0 = V + Shutdown Current V = 0V, V CC =.V + µa CONTROL STAGE V µa 0.9V V CC.8V Full 0. V CC Input Low Voltage V IL.8V < V CC.V Full 0..V < V CC.V Full 0. V.V < V CC.0V Full 0. Input High Voltage V IH 0.9V V CC.8V Full 0.8 V CC.8V < V CC.V Full V.V < V CC.V Full..V < V CC.0V Full. Input Current Clamped on or Full µa Over-Temperature Protection 0 Over-Temperature Hysteresis 0
TYPICAL PERFORMANCE CHARACTERISTICS 00 90 I O = 0mA Efficiency vs. Input Voltage 00 90 I O = 0mA Efficiency vs. Input Voltage Efficiency (%) 80 70 I O = 00mA I O = ma Efficiency (%) 80 70 I O = ma I O = 0mA 0 =.V 0 0.9..7...9. Input Voltage (V) 0 =.0V 0 0.9...7..9. Input Voltage (V).0 Output Voltage vs. Output Current Output Voltage vs. Output Current..0 V CC =.V =.V.0. V CC =.V =.0V Output Voltage (V)...8. Output Voltage (V).0.0.00.9.0 0 00 000.90 0 00 000 Output Current (ma) Output Current (ma) 000 Quiescent Current vs. Input Voltage 800 Maximum Output Current vs. Input Voltage Quiescent Current (μa) 00 = V =.V 0 0.9.7....9 Input Voltage (V). Maximum Output Current (ma) 700 00 =.V 00 =.V =.V 00 00 00 =.0V 00 0 0.9..9..9..9..9. Input Voltage (V)
TYPICAL PERFORMANCE CHARACTERISTICS (continued) Line Transient Response Line Transient Response V IN VIN =.8V to.v, RL = Ω, =.V 00mV/div 00mV/div V IN VIN = V to.v, RL = Ω, = V 00mV/div 00mV/div Time (ms/div) Time (ms/div) Load Transient Response Load Transient Response I OUT 0mA/div 0mV/div I OUT 0mA/div 0mV/div VIN =.V, IL = 0mA to 80mA, =.V VIN =.V, IL = 0mA to 80mA, = V Time (ms/div) Time (ms/div) Output Voltage in Continuous Mode Output Voltage in Continuous Mode I L 0mV/div 00mA/div I L 0mV/div 00mA/div VIN =.V, RL = Ω, =.V VIN =.V, RL = Ω, = V Time (μs/div) Time (μs/div)
TYPICAL PERFORMANCE CHARACTERISTICS (continued) Output Voltage in Discontinuous Mode Output Voltage in Power-Save Mode I L 0mV/div 0mA/div 0mV/div 0mA/div VIN =.V, RL =.kω, =.V I L VIN =.V, RL =.kω, =.0V Time (00ns/div) Time (0μs/div) Start-Up after Enable Start-Up after Enable I L VIN =.V, RL = Ω, =.V V/div V/div V/div 00mA/div I L VIN =.V, RL = 0Ω, = V V/div V/div V/div 00mA/div Time (00μs/div) Time (00μs/div) 00 Efficiency vs. Output Current 00 Efficiency vs. Output Current Efficiency (%) 80 0 V CC =.V V CC = 0.9V 0 V CC =.8 V 0 =.V 0 0.0 0. 0 00 000 Output Current (ma) Efficiency (%) 80 V CC =.8V 0 V CC =.V V CC = 0.9V 0 0 =.V 0 0.0 0. 0 00 000 Output Current (ma) 7
TYPICAL PERFORMANCE CHARACTERISTICS (continued) 00 Efficiency vs. Output Current Efficiency (%) 80 V CC =.V 0 V CC =.8V 0 V CC =.V 0 = V 0 0.0 0. 0 00 000 Output Current (ma) 8
TYPICAL APPLICATION CIRCUITS Power Supply C.7μF L.7μH SGM0 FB R R C V CC Boost Output Figure. Power Supply Solution for Maximum Output Power Operating from a Single or Dual Alkaline Cell Power Supply C.7μF L.7μH SGM0 FB R R C V CC Boost Output Figure. Power Supply Solution Having Small Total Solution Size Power Supply C.7μF L.7μH SGM0 FB C D LED Current Up to 0mA R Figure. Power Supply Solution for Powering White LEDs in Lighting Applications 9
TYPICAL APPLICATION CIRCUITS (continued) C 0.µF DS V CC ~ V CC Unregulated Auxiliary Output C µf Power Supply C.7μF L.7μH SGM0 FB R R C V CC Boost Output Figure. Power Supply Solution with Auxiliary Positive Output Voltage C 0.µF DS C µf V CC ~ -V CC Unregulated Auxiliary Output Power Supply C.7μF L.7μH SGM0 FB R R C V CC Boost Output Figure. Power Supply Solution with Auxiliary Negative Output Voltage 0
TYPICAL APPLICATION CIRCUITS (continued) Power Supply C L.7μH SGM0-. NC C.V Figure 7a. Basic Application Circuit for the Fixed Output Versions Power Supply C L.7μH SGM0-.0 NC C.0V Figure 7b. Basic Application Circuit for the Fixed Output Versions
APPLICATION INFORMATION Design Procedure The SGM0 DC/DC converter is intended for systems powered by a single-cell, up to triple-cell alkaline, NiCd, and NiMH battery with a typical terminal voltage between 0.9V and.v. It can also be used in systems powered by one-cell Li-Ion or Li-Polymer with a typical voltage between.v and.v. Programming Output Voltage In Figure, the output voltage of the SGM0 DC/DC converter can be adjusted with an external resistor divider. The typical value of the voltage at the FB pin is 00mV. The maximum recommended value for the output voltage is.v. R and R are calculated using Equation : V V R = R ( OUT )= R ( OUT ) () V 00mV FB R is recommended to be 00kΩ. For example, if an output voltage of.v is needed, a 0kΩ resistor should be chosen for R. Inductor Selection A boost converter normally requires two main passive components for storing energy during the conversion. A boost inductor and a storage capacitor at the output are required. To select the boost inductor, it is recommended to keep the possible peak inductor current below the current limit threshold of the power switch in the chosen configuration. The highest peak current through the inductor and the switch depends on the output load, the input (V CC ), and the output voltage ( ). Estimation of the maximum average inductor current is done using Equation : I L = I O V 0.8 CC () The second parameter for choosing the inductor is the desired current ripple in the inductor. Normally, it is advisable to work with a ripple of less than 0% of the average inductor current. A smaller ripple reduces the magnetic hysteresis losses in the inductor, as well as output voltage ripple and EMI. But in the same way, regulation time rises at load changes. In addition, a larger inductor increases the total system costs. With these parameters, it is possible to calculate the value for the inductor by using Equation : L = ( V ΔI f V L OUT Parameter f is the switching frequency and ΔI L is the ripple current in the inductor. In typical applications, a.7µh inductance is recommended. The device has been optimized to operate with inductance values between.µh and 0µH. Nevertheless, operation with higher inductance values may be possible in some applications. Detailed stability analysis is then recommended. Care must be taken because load transients and losses in the circuit can lead to higher currents as estimated in Equation. Also, the losses in the inductor which include magnetic hysteresis losses and copper losses are a major parameter for total circuit efficiency. Input Capacitor At least a 0µF input capacitor is recommended to improve transient behavior of the regulator and EMI behavior of the total power supply circuit. A ceramic capacitor or a tantalum capacitor with a 00nF ceramic capacitor in parallel, placed close to the IC, is recommended. CC ) () For example, for an output current of 7mA at.v, at least an average current of 0mA flows through the inductor at a minimum input voltage of 0.9V.
APPLICATION INFORMATION (continued) Output Capacitor The major parameter necessary to define the output capacitor is the maximum allowed output voltage ripple of the converter. This ripple is determined by two parameters of the capacitor, the capacitance and the ESR. It is possible to calculate the minimum capacitance needed for the defined ripple, supposing that the ESR is zero, by using Equation : C MIN = IO ( V f ΔV V OUT Parameter f is the switching frequency and ΔV is the maximum allowed ripple. With a chosen ripple voltage of 0mV, a minimum capacitance of.µf is needed. In this value range, ceramic capacitors are a good choice. The ESR and the additional ripple created are negligible. It is calculated using Equation : CC ) () ΔV ESR = I O R ESR () The total ripple is the sum of the ripple caused by the capacitance and the ripple caused by the ESR of the capacitor. Additional ripple is caused by load transients. This means that the output capacitor has to completely supply the load during the charging phase of the inductor. The value of the output capacitance depends on the speed of the load transients and the load current during the load change. With the calculated minimum value of.µf and load transient considerations, the recommended output capacitance value is in the range of.7μf to µf. Care must be taken on capacitance loss caused by derating due to the applied DC voltage and the frequency characteristic of the capacitor. For example, larger form factor capacitors (in 0 size) have their self resonant frequencies in the same frequency range as the SGM0 operating frequency. So the effective capacitance of the capacitors used may be significantly lower. Therefore, the recommendation is to use smaller capacitors in parallel instead of one larger capacitor. Layout Considerations As for all switching power supplies, the layout is an important step in the design, especially at high-peak currents and high switching frequencies. If the layout is not carefully done, the regulator could show stability problems as well as EMI problems. Therefore, use wide and short traces for the main current path and for the power ground tracks. The input capacitor, output capacitor, and the inductor should be placed as close as possible to the IC. Use a common ground node for power ground and a different one for control ground to minimize the effects of ground noise. Connect these ground nodes at any place close to the ground pin of the IC. The feedback divider should be placed as close as possible to the ground pin of the IC. To lay out the control ground, it is recommended to use short traces as well, separated from the power ground traces. This avoids ground shift problems, which can occur due to superimposition of power ground current and control ground current. Thermal Information Implementation of integrated circuits in low-profile and fine-pitch surface-mount packages typically requires special attention to power dissipation. Many system-dependent issues such as thermal coupling, airflow, added heat sinks and convection surfaces, and the presence of other heat-generating components affect the power-dissipation limits of a given component. Three basic approaches for enhancing thermal performance follow.. Improving the power dissipation capability of the PCB design.. Improving the thermal coupling of the component to the PCB.. Introducing airflow in the system.
REVISION HISTORY NOTE: Page numbers for previous revisions may differ from page numbers in the current version. REV.A. to REV.A. Update the Typical Performance Characteristics Efficiency vs. Input Voltage ( =.V, =.0V)... APRIL 0 REV.A. to REV.A. Update the Electrical Characteristics V IH (0.9V V CC.8V).V - 0.8V CC... JANUARY 0 REV.A to REV.A. Update the Electrical Characteristics Switch Current Limit... Add dot on pin SOT--..., Changes from Original (JANUARY 0) to REV.A Changed from product preview to production data... All
PACKAGE INFORMATION PACKAGE OUTLINE DIMSIONS SOT-- D e e E E.9 0.99 b 0.9 0.9 RECOMMDED LAND PATTERN (Unit: mm) L A A A θ 0. c Symbol Dimensions In Millimeters Dimensions In Inches MIN MAX MIN MAX A.00.0 0.0 0.09 A 0.000 0.00 0.000 0.00 A.00.0 0.0 0.0 b 0.00 0.00 0.0 0.00 c 0.00 0.00 0.00 0.008 D.80.00 0. 0.9 E.00.700 0.09 0.07 E.0.90 0.0 0. e 0.90 BSC 0.07 BSC e.900 BSC 0.07 BSC L 0.00 0.00 0.0 0.0 θ 0 8 0 8 TX000.000
PACKAGE INFORMATION TAPE AND REEL INFORMATION REEL DIMSIONS TAPE DIMSIONS P P0 W Q Q Q Q Q Q B0 Q Q Q Q Q Q Reel Diameter P A0 K0 Reel Width (W) DIRECTION OF FEED NOTE: The picture is only for reference. Please make the object as the standard. KEY PARAMETER LIST OF TAPE AND REEL Package Type Reel Diameter Reel Width W A0 B0 K0 P0 P P W Pin Quadrant SOT-- 7 9..7..7.0.0.0 8.0 Q DD000 TX0000.000
PACKAGE INFORMATION CARTON BOX DIMSIONS NOTE: The picture is only for reference. Please make the object as the standard. KEY PARAMETER LIST OF CARTON BOX Reel Type Length Width Height Pizza/Carton 7 (Option) 8 7 8 7 0 8 DD000 TX0000.000