LTC310813108f TYPICAL APPLICATION DESCRIPTIONUltralow Voltage Step-Up Converter and Power ManagerThe LTC®3108 is a highly integrated DC/DC converter ideal for harvesting and managing surplus energy from extremely low input voltage sources such as TEGs (thermoelectric generators), thermopiles and small solar cells. The step-up topology operates from input voltages as low as 20mV.Using a small step-up transformer, the LTC3108 provides a complete power management solution for wireless sensing and data acquisition. The 2.2V LDO powers an external microprocessor, while the main output is programmed to one of four fi xed voltages to power a wireless transmitter or sensors. The power good indicator signals that the main output voltage is within regulation. A second output can be enabled by the host. A storage capacitor provides power when the input voltage source is unavailable. Extremely low quiescent current and high effi ciency design ensure the fastest possible charge times of the output reservoir capacitor.The LTC3108 is available in a small, thermally enhanced 12-lead (4mm × 3mm) DFN package and a 16-lead SSOP package.Wireless Remote Sensor Application Powered From a Peltier Cell FEATURES APPLICATIONSn Operates from Inputs of 20mVn Complete Energy Harvesting Power Management System - Selectable VOUT of 2.35V, 3.3V, 4.1V or 5V - LDO: 2.2V at 3mA - Logic Controlled Output - Reserve Energy Outputn Power Good Indicatorn Ultralow IQ: 6μAn Uses Compact Step-Up Transformersn Small 12-Lead (4mm × 3mm) DFN or 16-Lead SSOP Packagesn Remote Sensors and Radio Powern Surplus Heat Energy Harvestingn HVACn Industrial Wireless Sensingn Automatic Meteringn Building Automationn Predictive Maintenance3108 TA01aC1THERMOELECTRICGENERATOR20mV TO 500mVC2SWVS2VS1VOUT2PGOOD2.2V470μFPGDVLDOVSTORE+VOUTVOUT2_ENLTC3108VAUX GND0.1F6.3V5V3.3V1μF1nF220μF1:100330pFSENSORSRF LINKμP2.2μF+++VOUT Charge TimeL, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.VIN (mV)TIME (sec)101100100003108 TA01b0100 150 25050200 300 350 400VOUT = 3.3VCOUT = 470μF1:100 Ratio1:50 Ratio1:20 RatioLTC310823108f ABSOLUTE MAXIMUM RATINGSSW Voltage ..................................................–0.3V to 2VC1 Voltage ....................................................–0.3V to 6VC2 Voltage (Note 5) .........................................–8V to 8VVOUT2, VOUT2_EN ...........................................–0.3V to 6VVAUX ....................................................15mA into VAUX(Note 1)12111098713GND123456SWC2C1VOUT2_ENVS1VS2VAUXVSTOREVOUTVOUT2VLDOPGDTOP VIEWDE PACKAGE12-LEAD (4mm s 3mm) PLASTIC DFNTJMAX = 125°C, θJA = 43°C/W, θJC = 4.3°C/WEXPOSED PAD (PIN 13) IS GND, MUST BE SOLDERED TO PCB (NOTE 4)GN PACKAGE16-LEAD PLASTIC SSOP NARROW12345678TOP VIEW161514131211109GNDVAUXVSTOREVOUTVOUT2VLDOPGDGNDGNDSWC2C1VOUT2_ENVS1VS2GNDTJMAX = 125°C, θJA = 110°C/W, θJC = 40°C/W PIN CONFIGURATION ELECTRICAL CHARACTERISTICSPARAMETER CONDITIONS MIN TYP MAX UNITSMinimum Start-Up Voltage Using 1:100 Transformer Turns Ratio, VAUX = 0V 20 50 mVNo-Load Input Current Using 1:100 Transformer Turns Ratio; VIN = 20mV, VOUT2_EN = 0V; All Outputs Charged and in Regulation3mAInput Voltage Range Using 1:100 Transformer Turns RatiolVSTARTUP500 mV The l denotes the specifi cations which apply over the specifi ed operating junction temperature range of –40°C to 85°C, otherwise specifi cations are at TJ = 25°C. VAUX = 5V, unless otherwise noted.ORDER INFORMATIONLEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGELTC3108EDE#PBF LTC3108EDE#TRPBF 310812-Lead (4mm × 3mm) Plastic DFN–40°C to 85°CLTC3108IDE#PBF LTC3108IDE#TRPBF 310812-Lead (4mm × 3mm) Plastic DFN–40°C to 85°CLTC3108EGN#PBF LTC3108EGN#TRPBF 3108 16-Lead Plastic SSOP –40°C to 85°CLTC3108IGN#PBF LTC3108IGN#TRPBF 3108 16-Lead Plastic SSOP –40°C to 85°CConsult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi ed by a label on the shipping container.For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifi cations, go to: http://www.linear.com/tapeandreel/VS1, VS2, VAUX, VOUT, PGD ........................–0.3V to 6VVLDO, VSTORE ............................................–0.3V to 6VOperating Junction Temperature (Note 2) .... –40°C to 85°CStorage Temperature Range .................. –65°C to 125°CLTC310833108fNote 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime.Note 2: The LTC3108E is guaranteed to meet performance specifi cations from 0°C to 85°C. Specifi cations over the –40°C to 85°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. The LTC3108I is guaranteed to meet specifi cations over the full –40°C to 85°C operating junction temperature range. Note that the maximum ambient temperature is determined by specifi c operating conditions in conjunction with board layout, the rated package thermal resistance and other environmental factors.Note 3: Specifi cation is guaranteed by design and not 100% tested in production.Note 4: Failure to solder the exposed backside of the package to the PC board ground plane will result in a thermal resistance much higher than 43°C/W.Note 5: The absolute maximum rating is a DC rating. Under certain conditions in the applications shown, the peak AC voltage on the C2 pin may exceed ±8V. This behavior is normal and acceptable because the current into the pin is limited by the impedance of the coupling capacitor. ELECTRICAL CHARACTERISTICS The l denotes the specifi cations which apply over the specifi ed operating junction temperature range of –40°C to 85°C, otherwise specifi cations are at TJ = 25°C. VAUX = 5V, unless otherwise noted.PARAMETER CONDITIONS MIN TYP MAX UNITSOutput Voltage VS1 = VS2 = GNDVS1 = VAUX, VS2 = GNDVS1 = GND, VS2 = VAUXVS1 = VS2 = VAUXllll2.303.2344.0184.902.3503.3004.1005.0002.403.3664.1825.10VVVVVOUT Quiescent Current VOUT = 3.3V, VOUT2_EN = 0V 0.2 μAVAUX Quiescent Current No Load, All Outputs Charged 6 9