LTC3106 300mA Low Voltage Buck-Boost Converter with PowerPath and 1.6µA Quiescent Current Features Description Dual Input Buck-Boost with Integrated PowerPath™ Manager n Ultralow Start-Up Voltages: 850mV Start with No Backup Source, 300mV with a Backup Source n Compatible with Primary or Rechargeable Backup Batteries n Digitally Selectable V OUT and VSTORE n Maximum Power Point Control n Ultralow Quiescent Current: 1.6μA n Regulated Output with V or V IN STORE Above, Below or Equal to the Output n Optional Backup Battery Trickle Charger n Shelf Mode Disconnect Function to Preserve Battery Shelf Life n Burst Mode® Operation n Accurate RUN Pin Threshold n Power Good Output Voltage Indicator n Selectable Peak Current Limit: 90mA/650mA n Available in Thermally Enhanced 3mm × 4mm 16-Pin QFN and 20-Pin TSSOP Packages The LTC®3106 is a highly integrated, ultralow voltage buckboost DC/DC converter with automatic PowerPath management optimized for multisource, low power systems. At no load, the LTC3106 draws only 1.6µA while creating an output voltage up to 5V from either input source. n If the primary power source is unavailable, the LTC3106 seamlessly switches to the backup power source. The LTC3106 is compatible with either rechargeable or primary cell batteries and can trickle charge a backup battery whenever there is an energy surplus available. Optional maximum power point control ensures power transfer is optimized between power source and load. The output voltage and backup voltage, VSTORE, are programmed digitally, reducing the required number of external components. Zero power Shelf Mode ensures that the backup battery will remain charged if left connected to the LTC3106 for an extended time. Additional features include an accurate turn-on voltage, a power good indicator for VOUT, a user selectable 100mA peak current limit setting for lower power applications, thermal shutdown as well as user selectable backup power and output voltages. Applications n n n n Wireless Sensor Networks Home or Office Building Automation Energy Harvesting Remote Sensors L, LT, LTC, LTM, Linear Technology, the Linear logo, Eterna and Burst Mode are registered trademarks and PowerPath is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 7432695 and 6366066. Typical Application Efficiency vs Input Voltage Solar Cell Input with Primary Battery Backup 100 + 10µF 470µF SW2 VAUX VIN VOUT 2.2µF LTC3106 1µF PGOOD 0.01µF VCC PRI 47µF 1M 3.3V 50mA EFFICIENCY (%) 600mV TO 5V PV CELLS + SW1 VSTORE VCAP ENVSTR RUN PGOOD VCC MPP ILIMSEL GND 3106 TA01a 110 100 90 90 85 80 80 75 70 VIN EFF. VIN P.L. VSTR EFF. VSTR P.L. 70 65 60 60 50 40 55 30 50 20 45 10 40 0.5 1 1.5 2 2.5 3 3.5 4 INPUT VOLTAGE (V) 4.5 5 POWER LOSS (mW) 3.6V TL-5955 PRIMARY BATTERY IOUT = 50mA 95 10µH 0 5.5 LTC3106 TA01b 3106f For more information www.linear.com/LTC3106 1 LTC3106 Absolute Maximum Ratings (Notes 1, 6) Supply Voltages VIN, VSTORE, VOUT, VCAP............................ –0.3V to 6V All Other Pins................................................ –0.3V to 6V Operating Junction Temperature Range (Notes 2, 3)............................................. –40°C to 125°C Storage Temperature Range................... –65°C to 150°C Lead Temperature (Soldering, 10 sec) FE Package........................................................ 300°C Pin Configuration TOP VIEW SW2 SW1 VSTORE VCAP TOP VIEW VSTORE 1 20 SW1 VCAP 2 19 SW2 VOUT 3 18 VIN NC 4 17 GND VAUX 5 13 RUN VCC 6 OS1 5 12 ILIMSEL OS1 7 14 ILIMSEL OS2 6 11 PRI OS2 8 13 PRI PGOOD 9 12 SS1 MPP 10 11 SS2 20 19 18 17 NC 1 16 VIN VOUT 2 15 GND VAUX 3 14 ENVSTR 21 GND MPP 9 10 SS1 8 SS2 7 PGOOD VCC 4 21 GND 16 ENVSTR 15 RUN FE PACKAGE 20-LEAD PLASTIC TSSOP UDC PACKAGE 20-LEAD (3mm × 4mm) PLASTIC QFN TJMAX = 125°C, θJA = 52°C/W, θJC = 7°C/W (Note 5) EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB TJMAX = 125°C, θJA = 48.6°C/W, θJC = 8.6°C/W (Note 5) EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB Order Information LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3106EUDC#PBF LTC3106EUDC#TRPBF LGQH 20-Lead (3mm × 4mm) Plastic QFN –40°C to 125°C LTC3106IUDC#PBF LTC3106IUDC#TRPBF LGQH 20-Lead (3mm × 4mm) Plastic QFN –40°C to 125°C LTC3106EFE#PBF LTC3106EFE#TRPBF LTC3106FE 20-Lead Plastic TSSOP –40°C to 125°C LTC3106IFE#PBF LTC3106IFE#TRPBF LTC3106FE 20-Lead Plastic TSSOP –40°C to 125°C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified 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 specifications, go to: http://www.linear.com/tapeandreel/. Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix. 3106f 2 For more information www.linear.com/LTC3106 LTC3106 Electrical Characteristics The l denotes the specifications which apply over the specified junction temperature range, otherwise specifications are at TA = 25°C (Note 2). VIN = 1.5V, VOUT = 3.3V, VSTORE = 3.6V and VAUX in regulation unless otherwise noted. PARAMETER VIN Start-Up Voltage VIN Maximum Operating Voltage VIN Minimum Operating Voltage VIN Minimum No-Load Start-Up Power VIN Undervoltage Quiescent Current Shutdown Current – VIN Quiescent Current – VIN VSTORE Maximum Operating Voltage VSTORE Minimum Operating Voltage VSTORE Under Voltage Lockout VSTORE Operating Voltage (Note 7) Output Regulation Voltage Quiescent Current – VAUX Quiescent Current – VOUT Quiescent Current – VSTORE Shutdown Current – VSTORE Shelf Mode VSTORE Leakage Current N-Channel MOSFETs – Leakage Current P-Channel MOSFETs – Leakage Current N-Channel MOSFET B and C Switch RDS(ON) P-Channel MOSFET A1 RDS(ON) P-Channel MOSFET A2 RDS(ON) P-Channel MOSFET D1 RDS(ON) P-Channel MOSFET D2 RDS(ON) CONDITIONS Start-Up from VIN, VOUT = VAUX = VSTORE = 0V, RUN = VIN VSTORE in Operating Voltage Limits, RUN > 0.613V, ENVSTR Pin > 0.8V (Minimum Voltage Is Load Dependent) Start-Up from VIN, RUN = VIN, VOUT = VAUX = VSTORE = 0V Start-Up from VIN, RUN = VIN, VOUT = VAUX = VSTORE = 0V VSTORE = 0V, RUN = 0 TJ = –40°C to 85°C (Note 4) MIN TYP 0.85 0.25 l l l l Switching Enabled, VOUT in Regulation, Non-Switching Switching Enabled, VOUT in Regulation, Non-Switching, TJ = –40°C to 85°C (Note 4) PRI = VCC, ENVSTR = VSTORE VOUT in Regulation, VCAP Shorted to VSTORE, PRI = VCC, ENVSTR = VSTORE PRI = VCC, ENVSTR = VSTORE SS1 = 0V, SS2 = 0V OV UV l l l 1.730 3.90 2.70 SS1 = 0V, SS2 = VCC OV UV l l SS1 = VCC, SS2 = 0V OV UV SS1 = VCC, SS2 = VCC 0.3 MAX 1.2 5.1 0.35 UNITS V V V 12 1 300 300 0.1 0.1 2 750 450 1 0.3 µW µA nA nA µA µA 4.3 V V 1.778 4.00 2.78 1.826 4.10 2.86 2.81 1.85 2.90 1.90 2.99 1.95 l l 2.91 2.08 3.00 2.15 3.08 2.21 OV UV l l 3.90 2.91 4.00 3.00 4.10 3.08 1.8V VOUT Selected TJ = –40°C to 85°C (Note 4) 2.2V VOUT Selected TJ = –40°C to 85°C (Note 4) 3.3V VOUT Selected TJ = –40°C to 85°C (Note 4) 5V VOUT Selected TJ = –40°C to 85°C (Note 4) Enabled, VOUT in Regulation, Non-Switching, TJ = –40°C to 85°C (Note 4) Enabled, VOUT in Regulation, Non-Switching, TJ = –40°C to 85°C (Note 4) Enabled, VOUT in Regulation, Non-Switching, VCAP Shorted to VSTORE TJ = –40°C to 85°C (Note 4) VIN = 0V, VCAP Shorted to VSTORE, ENVSTR = 0V TJ = –40°C to 85°C (Note 4) Isolated VSTORE, ENVSTR = 0V B and C Switches A1, A2, D1 and D2 Switches VIN = 5V VIN = 5V VSTORE = VCAP = 4.2V VOUT = 3.3V VSTORE = VCAP = 4.2V l 1.75 1.755 2.14 2.145 3.22 3.23 4.90 4.92 1.8 1.8 2.2 2.2 3.3 3.3 5.0 5.0 1.85 1.845 2.25 2.245 3.40 3.38 5.10 5.08 V V V V V V V V V V V V V V V V V 1.6 1.6 0.1 0.1 0.1 3 2.5 1 0.3 1 µA µA µA µA µA 0.1 0.1 0.1 0.1 0.1 0.1 0.5 0.5 1.9 0.9 2.9 0.3 0.7 0.3 25 1 1 µA µA µA nA µA µA Ω Ω Ω Ω Ω l 2.1 l l l l l l l l 3106f For more information www.linear.com/LTC3106 3 LTC3106 Electrical Characteristics The l denotes the specifications which apply over the specified junction temperature range, otherwise specifications are at TA = 25°C (Note 2). VIN = 1.5V, VOUT = 3.3V, VSTORE = 3.6V and VAUX in regulation unless otherwise noted. PARAMETER P-Channel MOSFET AUXSW RDS(ON) P-Channel VSTORE Isolation MOSFET RDS(ON) Peak Current Limit (VOUT) VALLEY Current Limit Peak Current Limit (VSTORE Charging) PGOOD Threshold PGOOD Hysteresis PGOOD Voltage Low PGOOD Leakage Current VIH Digital Input High Logic Level VIL Digital Input Low Logic Level Digital Input Leakage Current ENVSTR Input Leakage Current Auxiliary Voltage Threshold Auxiliary Voltage Hysteresis MPP Pin Output Current MPP Pin Shutdown Current MPP Disable Threshold RUN Threshold - Enable Reference Accurate RUN Threshold - Enable Switching from VIN Accurate RUN Hysteresis RUN Input Current CONDITIONS VAUX = 5.4V VSTORE = 4.2V VOUT Powered from VIN, ILIMSEL > 0.8V VOUT Powered from VIN, ILIMSEL = 0V VOUT Powered from VSTORE, ILIMSEL > 0.8V VOUT Powered from VSTORE, ILIMSEL = 0V VOUT Powered from VIN, ILIMSEL > 0.8V VOUT Powered from VIN, ILIMSEL = 0V VOUT Powered from VSTORE, ILIMSEL > 0.8V VOUT Powered from VSTORE, ILIMSEL = 0V VSTORE Powered from VIN VOUT Falling, Percentage Below VOUT Percentage of VOUT IPGOOD = 100µA VPGOOD = 5V Pins: OS[1:2], SS[1:2], ILIMSEL, ENVSTR, PRI Pins: OS[1:2], SS[1:2], ILIMSEL, ENVSTR, PRI Pin Voltage = 5.2V, Pins: OS[1:2], SS[1:2], ILIMSEL, PRI MIN l l l l l l l l l l 530 60 140 60 300 10 30 10 60 –11 l 0.1 l l RUN Pin Voltage Increasing TJ = –40°C to 85°C (Note 4) Note 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 LTC3106 is tested under pulsed load conditions such that TJ ≈TA. The LTC3106E is guaranteed to meet specifications from 0°C to 85°C junction temperature. Specifications over the –40°C to 125°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. The LTC3106I is guaranteed over the full –40°C to 125°C operating junction temperature range. The junction temperature (TJ) is calculated from the ambient temperature (TA ) and power dissipation (PD)according to the formula: TJ = TA + (PD)(θJA°C/W) where θJA is the package thermal impedance. Note the maximum ambient temperature consistent with these specifications is determined by specific operating conditions in conjunction with board layout, the rated package thermal resistance and other environmental factors. Note 3: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. The maximum l MAX –7 10 0.8 l VAUX Rising VAUX Falling, Restart VAUX Charging VMPP = 0.6V VMPP = VCC Voltage Below VCC TYP 3 2 725 100 200 100 400 44 70 44 100 –9 3 0.2 0.1 1.21 –1 0.15 0.585 0.591 44 5.2 50 1.5 0.1 –0.8 0.4 0.6 0.6 100 0.1 0.3 10 80 1.72 10 0.55 0.615 0.609 10 UNITS Ω Ω mA mA mA mA mA mA mA mA mA % % V nA V V nA nA V mV µA nA V V V V mV nA rated junction temperature will be exceeded when this protection is active. Continuous operation above the maximum operating junction temperature may impair device reliability or permanently damage the device. Note 4: Specification is guaranteed by design and not 100% tested in production. Note 5: Failure to solder exposed backside of the package to the PC board will result in a higher thermal resistance Note 6: Voltage transients on the switch pins beyond the DC limits specified in Absolute Maximum Ratings are non-disruptive to normal operation when using good layout practices as described elsewhere in the data sheet and as seen on the demo board. Note 7: If PRI = GND, then charging is enabled on VSTORE whenever surplus energy is available from VIN. The OV and UV thresholds are the maximum charge and discharge levels controlled by the LTC3106. Note 8: Some of the IC electrical characteristics are measured in an open-loop test configuration that may differ from the typical operating conditions. These differences are not critical for the accuracy of the parameter and will not impact operation. 3106f 4 For more information www.linear.com/LTC3106 LTC3106 Typical Performance Characteristics 1k VOUT = 1.8V 60 50 40 30 VIN = 1V VIN = 2V VIN = 3V VIN = 4V VIN = 5V 20 10 0 0.001 0.01 0.1 1 10 LOAD CURRENT (mA) POWER LOSS (mW) 70 VOUT = 1.8V 10 1 0.01 0.001 0.1 1 10 LOAD CURRENT (mA) 100 VOUT = 2.2V 90 0.1 vs Load 100 90 0.1 1 10 LOAD CURRENT (mA) Current VOUT = 3.3V 0.01 40 VIN = 1V VIN = 2V VIN = 3V VIN = 4V VIN = 5V 30 20 10 0 0.001 100 500 0.01 0.1 1 10 LOAD CURRENT (mA) 3106 G04 1k VOUT = 3.3V 10 1 0.1 0.01 0.001 100 500 VIN = 1V VIN = 3V VIN = 5V 0.01 VIN Power Loss vs Load Current 1k V OUT = 5V 40 VIN = 1V VIN = 2V VIN = 3V VIN = 4V VIN = 5V 30 20 10 0.01 0.1 1 10 LOAD CURRENT (mA) 100 500 3106 G07 POWER LOSS (mW) 50 10 1 0.1 0.01 0.001 VIN = 1V VIN = 3V VIN = 5V 0.01 0.1 1 10 LOAD CURRENT (mA) 100 500 3106 G08 0.1 1 10 LOAD CURRENT (mA) 100 500 3106 G06 Light Load Power Loss vs Input Voltage (VIN) VOUT = 1.8V AT 10µA VOUT = 5V AT 10µA VOUT = 1.8V AT 2µA VOUT = 5V AT 2µA 100 60 100 500 VIN Power Loss vs Load Current 3106 G05 VOUT = 5V 70 0.1 1 10 LOAD CURRENT (mA) 100 50 80 EFFICIENCY (%) 1k 60 VIN Efficiency vs Load Current 0 0.001 VIN = 1V VIN = 2V VIN = 3V VIN = 4V VIN = 5V 30 3106 G03 VIN Efficiency vs Load Current 70 VIN = 1V VIN = 3V VIN = 5V 0.01 40 0 0.001 100 500 POWER LOSS (µW) 0.01 0.001 50 10 80 EFFICIENCY (%) POWER LOSS (mW) 100 1 60 20 VIN = 1V VIN = 3V VIN = 5V 0.01 70 3106 G02 VIN Power Loss vs Load Current 10 VOUT = 2.2V 80 0.1 100 500 VIN Efficiency vs Load Current 90 3106 G01 1k 100 100 80 EFFICIENCY (%) VIN Power Loss vs Load Current EFFICIENCY (%) 90 VIN Efficiency vs Load Current POWER LOSS (mW) 100 TA = 25°C unless otherwise noted. 100 10 0 0.5 1 1.5 2 2.5 3 3.5 4 INPUT VOLTAGE, VIN (V) 4.5 5 3106 G09 3106f For more information www.linear.com/LTC3106 5 LTC3106 Typical Performance Characteristics VSTORE/VCAP Efficiency vs Load Current 90 VSTORE/VCAP Power Loss vs Load Current 100 VOUT = 1.8V 80 POWER LOSS (mW) EFFICIENCY (%) 60 50 40 30 20 0 0.001 0.01 0.1 1 10 LOAD CURRENT (mA) 0.01 0.001 100 0.01 60 50 40 30 100 0.01 0.1 1 10 LOAD CURRENT (mA) 30 0.01 0.1 1 10 LOAD CURRENT (mA) 100 3106 G16 100 20 VOUT = 5V 18 16 1 0.01 0.001 0.1 1 10 LOAD CURRENT (mA) No Load Input Current vs Input Voltage 0.1 VSTORE/VCAP = 4.2V VSTORE/VCAP = 3.1V VSTORE/VCAP = 2V 0.01 3106 G15 INPUT CURRENT (µA) 40 10 0.01 0.001 100 10 POWER LOSS (mW) EFFICIENCY (%) 80 50 VSTORE/VCAP = 4.2V VSTORE/VCAP = 3.1V VSTORE/VCAP = 2V 1 VSTORE/VCAP Power Loss vs Load Current VOUT = 5V 100 VOUT = 3.3V 3106 G14 VSTORE/VCAP Efficiency vs Load Current 0.1 1 10 LOAD CURRENT (mA) 0.1 VSTORE/VCAP = 4.2V VSTORE/VCAP = 3.1V VSTORE/VCAP = 2V 3106 G13 0 0.001 100 70 0 0.001 100 60 0.01 VSTORE/VCAP Power Loss vs Load Current 10 10 70 VSTORE/VCAP = 4.2V VSTORE/VCAP = 3.1V VSTORE/VCAP = 2V 3106 G12 VOUT = 3.3V 20 20 30 0 0.001 100 POWER LOSS (mW) 0.1 90 0.1 1 10 LOAD CURRENT (mA) 80 EFFICIENCY (%) POWER LOSS (mW) 90 1 100 40 VSTORE/VCAP Efficiency vs Load Current 100 0.1 1 10 LOAD CURRENT (mA) 50 3106 G11 VSTORE/VCAP = 4.2V VSTORE/VCAP = 3.1V VSTORE/VCAP = 2V 0.01 60 10 VOUT = 2.2V 0.01 0.001 70 20 3106 G10 10 80 1 VSTORE/VCAP Power Loss vs Load Current 100 VOUT = 2.2V 90 VSTORE/VCAP = 4.2V VSTORE/VCAP = 3.1V VSTORE/VCAP = 2V 0.1 VSTORE/VCAP = 4.2V VSTORE/VCAP = 3.1V VSTORE/VCAP = 2V 10 100 VOUT = 1.8V 10 70 VSTORE/VCAP Efficiency vs Load Current EFFICIENCY (%) 100 TA = 25°C unless otherwise noted. VSTORE/VCAP = 4.2V VSTORE/VCAP = 3.1V VSTORE/VCAP = 2V 0.01 0.1 1 10 LOAD CURRENT (mA) 100 3106 G17 14 12 10 8 6 4 2 0 1 2 3 4 INPUT VOLTAGE (V) 5 3106 G18 3106f 6 For more information www.linear.com/LTC3106 LTC3106 Typical Performance Characteristics Normalized VOUT, Accurate RUNTH vs Temperature 30 10 PERCENT CHANGE (%) PERCENT CHANGE (%) 20 0 –10 –20 –30 –40 –50 –32 –14 4 22 40 58 76 94 112 130 TEMPERATURE (°C) 3106 G19 1.0 ACCURATE RUN THRESHOLD 0.9 VOUT = 3.3V 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 –0.0 –0.1 –0.2 –0.3 –0.4 –0.5 –50 –30 –10 10 30 50 70 90 110 130 150 TEMPERATURE (°C) Normalized Input Voltage UVLO vs Temperature 1.0 0.9 0.8 0.7 PERCENT CHANGE (%) Normalized RUN Threshold vs Temperature TA = 25°C unless otherwise noted. 0.6 0.5 0.4 0.3 0.2 0.1 –0.0 –0.1 –0.2 –50 –30 –10 10 30 50 70 90 110 130 150 TEMPERATURE (°C) 3106 G21 3106 G20 Start-Up Into Resistive Load L = 10µH 600 1k Maximum Output Current vs Input Voltage (VIN) Maximum Output Current vs Input Voltage (VSTORE/VCAP) 1k ILIMSEL = HI ILIMSEL = HI RMIN (Ω) 400 300 200 100 10 VOUT = 1.8V VOUT = 2.2V VOUT = 3.3V VOUT = 5V 100 0 0.5 1 1.5 2 2.5 3 3.5 4 INPUT VOLTAGE (V) 4.5 5 1 5.5 0 0.5 1 3106 G22 Normalized VIN Start-Up Voltage vs Temperature 8 OUTPUT CURRENT (mA) OUTPUT CURRENT (mA) 500 100 1.5 2 2.5 3 3.5 4 INPUT VOLTAGE, VIN (V) 4.5 100 10 1 1.5 5 3106 G23 Maximum Output Current vs Input Voltage (VIN) VOUT = 1.8V VOUT = 2.2V VOUT = 3.3V VOUT = 5V 2 2.5 3 3.5 4 INPUT VOLTAGE, VSTORE/VCAP (V) 4.5 3106 G24 Maximum Output Current vs Input Voltage (VSTORE/VCAP) 100 6 2 0 –2 –4 –6 10 ILIMSEL = LO VOUT = 1.8V VOUT = 2.2V VOUT = 3.3V VOUT = 5V –8 –10 –12 –50 –30 –10 10 30 50 70 90 110 130 150 TEMPERATURE (°C) 3106 G25 OUTPUT CURRENT (mA) OUTPUT CURRENT (mA) PERCENT CHANGE (%) 4 1 0 0.5 1 1.5 2 2.5 3 3.5 4 INPUT VOLTAGE, VIN (V) 4.5 5 3106 G26 10 1.5 ILIMSEL = LO VOUT = 1.8V VOUT = 2.2V VOUT = 3.3V VOUT = 5V 2 2.5 3 3.5 4 INPUT VOLTAGE, VSTORE/VCAP (V) 4.5 3106 G27 3106f For more information www.linear.com/LTC3106 7 LTC3106 Typical Performance Characteristics Normalized Output Voltage Regulation vs Load Current L = 10µH LOAD REGULATION (%) 1 COUT = 47µF ILIMSEL = HI COUT = 100µF COUT = 47µF 0.5 0 IL 200mA/DIV –0.5 –1.0 –1.5 ILOAD 100mA/DIV –2.0 100µs/DIV –2.5 –3.0 0.001 0.01 0.1 1 10 LOAD CURRENT (mA) Normalized MPP Output vs Temperature Inductor Current vs Load Current 3106 G29 PERCENT CHANGE FROM 25°C (%) 1.0 TA = 25°C unless otherwise noted. 0 –1 –2 –3 –4 –50 –30 –10 10 30 50 70 90 110 130 150 TEMPERATURE (°C) 100 500 3106 G30 3106 G28 No Load Input Current vs Input Voltage, MPP Enabled 5VIN to 3.3VOUT Load Step 10mA to 300mA 700 5VIN to 3.3VOUT Load Step 100µA to 40mA COUT = 47µF COUT = 47µF, ILIMSEL = LO INPUT CURRENT (µA) 600 500 VOUT 200mV/DIV 400 VOUT 200mA/DIV VOUT 100mV/DIV COUT = 100µF 40mA 300mA 300 ILOAD 200mA/DIV 200 100 ILIMSEL = HI 0 0.4 1.3 2.2 3.2 INPUT VOLTAGE (V) 4.1 ILOAD 20mA/DIV 10mA 1ms/DIV 100µA 3106 G32 100µA 5ms/DIV 3106 G33 5 3106 G31 Boost Mode at VIN = 1.5V VOUT = 3.3V, 100mA Buck-Boost Mode at VIN = 3.5V VOUT = 3.3V 100mA VAUX 50mV/DIV VAUX 20mV/DIV VOUT 50mV/DIV VOUT 100mV/DIV VAUX 50mV/DIV VOUT 100mV/DIV IL 200mA/DIV IL 400mA/DIV IL 200mA/DIV 50µs/DIV L = 10µH COUT = 47µF ILIMSEL = HI Buck Mode at VIN = 4.3V VOUT = 3.3V, 100mA 50µs/DIV 3106 G34 50µs/DIV 3106 G35 L = 10µH COUT = 47µF ILIMSEL = HI 3106 G36 L = 10µH COUT = 47µF ILIMSEL = HI 3106f 8 For more information www.linear.com/LTC3106 LTC3106 Typical Performance Characteristics No-Load Start-Up from Low Power Source VSTORE = 0V, VIN = RUN Buck Mode at VIN = 5V VOUT = 3.3V, 300mA VAUX 100mV/DIV VIN 1V/DIV IL 200mA/DIV 50µs/DIV 3106 G37 RUN 2V/DIV 5s/DIV 150 VIN = 2V, COUT = 47µF VIN = 5V, COUT = 47µF VIN = 2V, COUT = 100µF VIN = 5V, COUT = 100µF 125 120 100 80 60 40 100 L = 10µH 100 200 VIN = 2V, COUT = 47µF VIN = 5V, COUT = 47µF VIN = 2V, COUT = 100µF VIN = 5V, COUT = 100µF 180 L = 10µH 75 50 3106 G40 200 175 75 0 0.0001 0.001 L = 10µH VIN = 2V, COUT = 47µF VIN = 5V, COUT = 47µF VIN = 2V, COUT = 100µF VIN = 5V, COUT = 100µF 0.01 0.1 1 LOAD CURRENT (mA) 10 100 3106 G43 RIPPLE VOTLAGE (mVP-P) 125 100 L = 10µH 120 100 80 60 40 0.01 0.1 1 LOAD CURRENT (mA) 10 0 0.0001 0.001 0.01 0.1 1 10 LOAD CURRENT (mA) 100 100 150 125 1k 3106 G42 1.8V Output Voltage Ripple vs Load Current (ILIMSEL High) 150 25 140 3106 G41 5V Output Voltage Ripple vs Load Current (ILIMSEL Low) 50 160 VIN = 2V, COUT = 47µF VIN = 5V, COUT = 47µF VIN = 2V, COUT = 100µF VIN = 5V, COUT = 100µF 20 0 0.0001 0.001 1k 3106 G39 5V Output Voltage Ripple vs Load Current (ILIMSEL High) 1.8V Output Voltage Ripple vs Load Current (ILIMSEL Low) 100 VIN = 2V, COUT = 47µF VIN = 5V, COUT = 47µF VIN = 2V, COUT = 100µF VIN = 5V, COUT = 100µF RIPPLE VOTLAGE (mVP-P) 0 0.0001 0.001 0.01 0.1 1 10 LOAD CURRENT (mA) RIPPLE VOTLAGE (mVP-P) 500µs/DIV 25 20 ILOAD = 30mA COUT = 47µF 3106 G38 3.3V Output Voltage Ripple vs Load Current (ILIMSEL Low) RIPPLE VOTLAGE (mVP-P ) RIPPLE VOTLAGE (mVP-P) 140 VOUT, 3.3V 200mV/DIV VOUT CHARGING PGOOD 2V/DIV 3.3V Output Voltage Ripple vs Load Current (ILIMSEL High) VIN, 2V 100mV/DIV RIPPLE VOTLAGE (mVpp) L = 10µH COUT = 47µF ILIMSEL = HI 160 VSTORE, 3V 100mV/DIV VAUX CHARGING VOUT, 3.3V 2V/DIV 180 VSTORE to VIN Switchover PIN = 100µW VIN_OC = 1.8V VOUT 50mV/DIV 200 TA = 25°C unless otherwise noted. L = 10µH 100 75 50 75 VIN = 2V, COUT = 47µF VIN = 5V, COUT = 47µF VIN = 2V, COUT = 100µF VIN = 5V, COUT = 100µF L = 10µH 50 25 25 0 0.0001 0.001 0.01 0.1 1 10 LOAD CURRENT (mA) 100 1k 3106 G44 0 0.0001 0.001 0.01 0.1 1 LOAD CURRENT (mA) 10 100 3106 G45 3106f For more information www.linear.com/LTC3106 9 LTC3106 Typical Performance Characteristics TA = 25°C unless otherwise noted. 5V VIN to 1.8V VOUT Load Step 10µA to 50mA Output Voltage Ripple 5V VIN, 3.3V VOUT 200mA 5V VIN to 1.8V VOUT Load Step 10µA to 200mA VAUX CHARGING VAUX 100mV/DIV ILOAD 50mA/DIV VOUT 100mV/DIV 10µA ILOAD 200mA/DIV 10µA 50mA COUT = 47µF 3106 G46 ILIMSEL = LOW 500µs/DIV 3106 G47 ILIMSEL = HIGH Maximum Slew Rate vs Input Voltage 1k 1.1 1.0 OUTPUT CURRENT (mA) INPUT VOLTAGE SLEW RATE (V/µs) 1.2 0.8 0.7 0.6 0.5 0.4 0.2 3 3.5 4 4.5 INPUT VOLTAGE VIN (V) 3106 G48 ILIMSEL = HI 100 10 1 VOUT = 1.8V VOUT = 2.2V VOUT = 3.3V VOUT = 5V 0.1 1.5 5 500µs/DIV Maximum Output Current vs Input Voltage (VSTORE Shelf Mode) 0.1 0 2.5 COUT = 100µF VOUT (AC) 100mV/DIV VOUT (AC) 50mV/DIV 100µs/DIV 10µA VOUT (AC) 100mV/DIV COUT = 100µF ILIMSEL = HIGH COUT = 100µF 200mA COUT = 47µF VOUT (AC) 50mV/DIV IL 500mA/DIV 10µA 2 3106 G49 Maximum Output Current vs Input Voltage (VSTORE Shelf Mode) 2.5 3 3.5 4 INPUT VOLTAGE, VSTORE (V) 4.5 3106 G50 Normalized Average Minimum Operating VSTORE vs Temperature 15.0 100 PRI = HI 10 ILIMSEL = LO 2 VOUT = 1.8V VOUT = 2.2V VOUT = 3.3V VOUT = 5V 2.5 3 3.5 4 INPUT VOLTAGE, VSTORE (V) 4.5 CHANGE IN VSTORE (%) OUTPUT CURRENT (mA) 12.5 10.0 7.5 5.0 2.5 0 –2.5 –5.0 –50 –30 –10 10 30 50 70 90 110 130 150 TEMPERATURE (°C) 3106 G51 3106 G52 3106f 10 For more information www.linear.com/LTC3106 LTC3106 Pin Functions (QFN/TSSOP) NC (Pin 1/Pin 4): No Connect. Not electrically connected internally. May be connected to PCB ground or left floating. VOUT (Pin 2/Pin 3): Programmable Output Voltage. Connect at least a 22μF low ESR capacitor to GND as close to the part as possible. Capacitor size may increase depending on output voltage ripple and load current requirements. VAUX (Pin 3/Pin 5): Auxiliary Voltage. This pin is a generated voltage rail used to power internal circuitry only. Connect a 2.2μF minimum ceramic capacitor to GND as close to the part as possible. Larger capacitors may also be used depending on the application start-up requirements. If larger capacitors are used maintain a minimum 10:1 VOUT to VAUX capacitor value ratio. VCC (Pin 4/Pin 6): Internal Supply Rail. Do not load. Used for powering internal circuitry and biasing the programming inputs only. Decouple with a 0.1μF ceramic capacitor placed as close to the part as possible. OS1, OS2 (Pins 5, 6/Pins 7, 8): VOUT Select Programming Inputs. Connect the pins to ground or VCC to program the output voltage according to Table 1. PGOOD (Pin 7/Pin 9): Power Good Indicator. Open-drain output that is pulled to ground if VOUT falls 8% below its programmed voltage. The PGOOD pin is not actively pulled to ground in shutdown. If pulled high the PGOOD pin will float high and will not be valid until 3.5ms after the part is enabled. MPP (Pin 8/Pin 10): Set Point Input for Maximum Power Point Control. Connect a resistor from MPP to GND to program the activation point for the MPP comparator. To disable the MPP circuit, connect MPP directly to the VCC pin. SS1, SS2 (Pins 10, 9/Pins 12, 11): VSTORE Select Programming Inputs. Connect the pins to ground or VCC to program the VSTORE voltage range according to Table 2. Only valid if PRI is low. Tie both to ground if PRI is high. PRI (Pin 11/Pin 13): Primary Battery Enable Input. Tie to VCC to enable the use of a non-rechargeable primary battery and to disable VSTORE pin charge capability. SS[1:2] are ignored if PRI = VCC. Tie to GND to use a secondary battery and enable charging. ILIMSEL (Pin 12/Pin 14): Current Limit Input Select. Tie to GND to disable the automatic power adjust feature and operate at the lowest peak current or tie to VCC to enable the power adjust feature for operation at higher peak inductor currents. RUN (Pin 13/Pin 15): Input to enable the IC and to set custom VIN undervoltage thresholds. There are two thresholds on the RUN pin. A voltage greater than 400mV (typ) will enable certain internal IC functions. The accurate RUN threshold is set at 600mV and enables VIN as an input. Tie this pin to VIN or connect to an external divider from VIN to provide an accurate undervoltage threshold. Tie to >600mV to allow sub-600mV operation from VIN. The accurate RUN pin threshold has 50mV of hysteresis provided internally. ENVSTR (Pin 14/Pin 16): Enable VSTORE Input. Tie to VSTORE to enable VSTORE as a backup input. Grounding this pin disables the use of VSTORE as a backup input source. GND (Pin 15/Pin 17 and Pin 21 Exposed Pad): Connect to PCB ground for internal electrical ground connection and for rated thermal performance. VIN (Pin 16/Pin 18): Main Supply Input. Decouple with minimum 10µF capacitor. Input capacitor value may be significantly larger (>100µF) depending on source impedance and load requirements. If larger capacitors are used a 1µF min ceramic capacitor should be also placed as close to the VIN pin as possible. SW1, SW2 (Pins 18, 17/Pins 20, 19): Buck-Boost Converter Switch Pins. Connect inductor between SW1 and SW2 pins. VSTORE (Pin 19/Pin 1): Secondary Supply Input. A primary or secondary rechargeable battery may be connected from this pin to GND to power the system in the event the input voltage is lost. When PRI pin is low, current will be sourced from this pin to trickle charge the storage element up to the maximum selected storage voltage. When PRI is high no charging will occur. Tie this pin to VCAP for primary 3106f For more information www.linear.com/LTC3106 11 LTC3106 Pin Functions (QFN/TSSOP) or high capacity secondary battery applications. For low capacity sources only tie VSTORE directly to the battery. Tie to GND if unused. batteries. Tie to VSTORE for primary or high capacity secondary battery applications. Decouple to GND with a capacitor large enough to handle the peak load current from VSTORE. Tie to GND if unused. VCAP (Pin 20/Pin 2): VSTORE Isolation Pin. Isolates VSTORE from the decoupling capacitor for low capacity backup Block Diagram SW1 VCAP SW2 SWD2 VBEST VAUX VSTORE AUXSW SWA2 VIN VCAP VBEST VOUT VBEST SWA1 VSTR_EN DRIVERS SWB IVAL/IZERO DETECT ADJ VBEST CNTRL VCAP SS2 600mV RUN 600mV 400mV VIN 600mV – + VSTORE COMP VIN VOUT VSTORE VAUX SLEEP COMP START LOGIC, CONTROL LOGIC AND STATE MACHINE – + – + UVLO COMP THERMAL SHUTDOWN MPP COMP ENVSTR VREF ILIMSEL VOUT VOLTAGE REFERENCE OS1 FB OS2 600mV ADJ PWR ADJ PRI GND VCC ACCURATE RUN COMP RUN COMP ADJ + – VBEST – + – + IPEAK DETECT SWC SS1 VOUT SWD1 VCC + – VSTR_EN + – VIN VIN + – PGOOD COMP 1.5µA MPP OUTPUT CURRENT MPP PGOOD 600mV 3106 BD 3106f 12 For more information www.linear.com/LTC3106 LTC3106 Operation Simplified Operational Flow Chart Using Accurate RUN with Primary Battery Backup ENVSTR = VSTORE = VCAP RUN = VIN OR EXTERNAL DIVIDER TAP PRI = HI SHUTDOWN ENVSTR > 0.8V AND/OR RUN > ENABLE THRESHOLD (0.4V TYP) 1 VBEST* > 1.5V (MAX) YES VIN > ACC. RUN THRESHOLD OR VIN > VIN(TURNON)** NO NO YES NO NO VIN > VIN START-UP VOLTAGE (0.85V TYP) VSTORE > VSTORE(MIN) 1 YES ASYNCHRONOUS START-UP NO YES VAUX > VAUX THRESHOLD VOUT > 1.2V (TYP) YES SYNCHRONOUS SWITCHING NO VAUX > 5.2V (TYP) VOUT IN REGULATION YES START COMPLETE/SLEEP * VBEST IS THE GREATER OF VAUX, VIN, VSTORE, VOUT ** VIN(TURNON) = 0.6V • (1 +R1/R2) 3106 SD01 3106f For more information www.linear.com/LTC3106 13 LTC3106 Operation Simplified Operational Flow Chart Using VIN UVLO with Primary Battery Backup ENVSTR = VSTORE = VCAP RUN > 0.6V (TYPICALLY TIED TO VSTORE) PRI = HI SHUTDOWN ENVSTR > 0.8V AND/OR RUN > ENABLE THRESHOLD (0.4V TYP) 1 VBEST* > 1.5V (MAX) YES VIN > VIN(UVLO) 0.3V (TYP) NO NO NO NO VIN > VIN START-UP VOLTAGE (0.85V TYP) VSTORE > VSTORE(MIN) 1 YES ASYNCHRONOUS START-UP NO YES VAUX = VAUX THRESHOLD VOUT > 1.2V (TYP) YES SYNCHRONOUS SWITCHING NO VAUX > 5.2V (TYP) VOUT IN REGULATION YES START COMPLETE/SLEEP * VBEST IS THE GREATER OF VAUX, VIN, VSTORE, VOUT 3106 SD02 3106f 14 For more information www.linear.com/LTC3106 LTC3106 Operation Simplified Operational Flow Chart Using Accurate RUN with Rechargeable Battery Backup ENVSTR = VSTORE = VCAP RUN = VIN OR EXTERNAL DIVIDER TAP PRI = GND SHUTDOWN ENVSTR > 0.8V AND/OR RUN > ENABLE THRESHOLD (0.4V TYP) 1 VBEST* > 1.5V (MAX) YES VIN > ACC. RUN THRESHOLD OR VIN > VIN(TURNON)** NO NO YES NO NO VIN > VIN START-UP VOLTAGE (0.85V TYP) VSTORE(UV) < VSTORE < VSTORE(OV) OR NO IF VSTORE LOCKED OUT*** 1 YES ASYNCHRONOUS START-UP NO YES VAUX = VAUX THRESHOLD VOUT > 1.2V (TYP) YES SYNCHRONOUS SWITCHING NO VAUX > 5.2V (TYP) VOUT IN REGULATION YES VSTORE > VSTORE(OV) * VBEST IS THE GREATER OF VAUX, VIN, VSTORE, VOUT NO CHARGE VSTORE YES ** VIN(TURNON) = 0.6V • (1 + R1/R2) *** VSTORE IS LOCKED OUT AS AN INPUT UNTIL VAUX = VAUX TH, IF VSTORE IS LESS THAN VSTORE(UV) WHEN LTC3106 IS FIRST ENABLED START COMPLETE/SLEEP 3106 SD03 3106f For more information www.linear.com/LTC3106 15 LTC3106 Operation Simplified Operational Flow Chart Using VIN UVLO with Rechargeable Battery Backup ENVSTR = VSTORE = VCAP RUN > 0.6V (TYPICALLY TIED TO VSTORE) PRI = HI SHUTDOWN ENVSTR > 0.8V AND/OR RUN > ENABLE THRESHOLD (0.4V TYP) 1 VBEST* > 1.5V (MAX) YES VIN > VIN(UVLO) 0.3V (TYP) NO NO NO YES NO VIN > VIN START-UP VOLTAGE (0.85V TYP) VSTORE(UV) < VSTORE < VSTORE(OV) OR NO IF VSTORE LOCKED OUT*** 1 YES ASYNCHRONOUS START-UP NO YES VAUX = VAUX THRESHOLD VOUT > 1.2V (TYP) YES SYNCHRONOUS SWITCHING NO VAUX > 5.2V (TYP) VOUT IN REGULATION YES VSTORE > VSTORE(OV) * VBEST IS THE GREATER OF VAUX, VIN, VSTORE, VOUT NO CHARGE VSTORE YES *** VSTORE IS LOCKED OUT AS AN INPUT UNTIL VAUX = VAUX TH, IF VSTORE IS LESS THAN VSTORE(UV) WHEN LTC3106 IS FIRST ENABLED START COMPLETE/SLEEP 3106 SD04 3106f 16 For more information www.linear.com/LTC3106 LTC3106 Operation Introduction The LTC3106 is a high performance two input, synchronous buck-boost converter with low quiescent current over a wide input voltage range (refer to graph G18). The PowerPath control architecture allows the use of a single inductor to generate a user selectable fixed regulated output voltage through seamless transition between either of the two power inputs. If input power is available (VIN) or the backup battery is present (VSTORE), the buck-boost regulator will operate from VIN providing up to 300mA to the load. Should the VIN source become unavailable the regulator will select VSTORE/VCAP as its input delivering up to 90mA to the load. If a rechargeable battery is used as the backup source, a low current recharge power path is also provided allowing use of excess input energy to charge the backup source if the output voltage is in regulation. User selectable upper and lower thresholds are available to handle multiple battery chemistries and to protect the battery from overcharge/deep discharge. Charging can be externally disabled using the PRI pin for use of a primary battery as the backup source. Both configurations are shown in Figure 1. In either configuration, VCAP is always enabled at start-up if ENVSTR is high to determine if VCAP is within the programmed voltage range. If VCAP is below the lower threshold it is latched off during start-up to minimize quiescent current draw from VCAP. Since the voltage on VCAP is continually monitored a very small 100nA typical quiescent current will persist with VCAP in shutdown (ENVSTR tied to GND). NONISOLATED VSTORE/VCAP BACKUP POWER ISHDN = 100nA LTC3106 VSTORE ILIMSEL VCAP VCC FOR IPEAK = 170mA GND FOR IPEAK = 100mA ISOLATED VSTORE/VCAP BACKUP POWER ISHDN = 0.1nA LTC3106 IPEAK = 100mA VSTORE ILIMSEL VCAP 3106 F01 Figure 1. VSTORE/VCAP Configurations Shutdown VIN The main input voltage, VIN, can be configured to operate over an extended voltage range to accommodate multiple power source types including but not limited to high impedance sources. An accurate RUN pin allows predictable regulator turn-on at a specified input voltage. Optional maximum power point control (MPPC) capability is also integrated into the LTC3106. Either can be used to ensure maximum power extraction from non-ideal power sources. VSTORE/VCAP A backup source can be tied to VSTORE. As shown in the Block Diagram, VSTORE can be isolated from VCAP by the isolation switch for near zero current draw requirements and lower output current levels. When using the isolation feature the ILIMSEL pin should be tied to ground due to the increased series resistance the isolation switch adds. For typical secondary and primary battery backup applications isolation is not needed, VSTORE and VCAP should be shorted together. In this configuration the ILIMSEL feature can be used to increase output current to higher. Either input source can be enabled independently or together. Bring ENVSTR below the worst-case logic threshold of 0.3V to disable VSTORE/VCAP as input or output if charging is enabled (PRI low). Bringing ENVSTR below 0.3V will also turn off the isolation switch if the LTC3106 is configured to isolate VSTORE from VCAP. A low voltage logic input on the RUN pin enables some circuit functions at 400mV typical while an accurate comparator enables VIN as an input. To disable VIN as an input, RUN must be below the accurate RUN threshold of 600mV (typ). To put the LTC3106 in shutdown mode the ENVSTR pin must be below 0.3V and the RUN pin must be brought below the worst-case low level logic threshold of 150mV. Accurate RUN Pin If RUN is brought below the 500mV accurate comparator falling threshold, the buck-boost converter will inhibit switching from VIN. Certain control circuits will remain powered unless RUN is brought below its low level logic threshold of 400mV. A small amount of current draw on VIN will still remain in this mode. 3106f For more information www.linear.com/LTC3106 17 LTC3106 Operation With the addition of an optional resistor divider as shown in Figure 2, the RUN pin can be used to establish a user programmable turn-on and turn-off threshold. This feature can be utilized to set an application specific VIN undervoltage threshold or to operate the converter from VIN in a hiccup mode from very low power sources. If VSTORE/VCAP is available as a backup power source, VIN input power priority over VSTORE/VCAP is only given if the RUN pin is above the accurate threshold. VIN R1 0.6V RUN R2 0.4V – + VOUT The main output voltage on VOUT can be powered from either input power source and is user programmed to one of four regulated voltages using the voltage select pins OS1 and OS2, according to Table 1. It is recommended that OS1 and OS2 be tied to either ground or VCC. Table 1. Output Voltage Selection ACCURATE RUN COMP ENABLE VIN OS1 OS2 0 0 1.8V 0 VCC 2.2V VCC 0 3.3V VCC VCC 5V LTC3106 + – ENABLE VREF, CLEAR SHUTDOWN LOW VOLTAGE LOGIC THRESH 3106 F02 Figure 2. Accurate RUN Pin Comparator The VIN input is enabled when the voltage on RUN exceeds 0.6V (nominal). Therefore, the turn-on voltage threshold on VIN can be set externally and is given by: VOUT. When the VAUX voltage drops to 5.1V typical, input power is briefly diverted to recharge VAUX. R1 VIN(TURNON) = 0.6V • 1+ R2 The RUN comparator includes a built-in hysteresis of approximately 100mV, so that the typical turn-off threshold will be; R1 VIN(TURNOFF) = 0.5V • 1+ R2 VAUX VAUX is charged up during start-up and is also refreshed as necessary from VIN or VSTORE/VCAP during normal operation. Once VAUX is fully charged or greater than either input voltage source it will power the LTC3106 active circuitry. The VAUX pin should be bypassed with a minimum 2.2μF capacitor. Once VAUX reaches 5.2V (typ), VOUT is allowed to start charging. Although minimized by design techniques the single inductor architecture allows some parasitic asynchronous charging of VAUX. An internal shunt regulator limits the maximum voltage on VAUX to 5.5V typical and shunts any excess current to OUTPUT VOLTAGE VCC An internal decision circuit determines the voltage on the VCC pin. VCC is the highest voltage of either VIN, VCAP, VOUT or VAUX. Although the VCC decision circuit is always active, when start-up is complete during normal operation VAUX will equal VCC. VCC should be decoupled with a 0.1µF capacitor placed as close as possible to the VCC pin. VCC is not designed to source or sink current externally. VCC may be used to terminate the LTC3106 logic inputs but should not otherwise be externally loaded. High Capacity Secondary Battery Backup Short VSTORE to VCAP for high capacity (>5mAh) backup power sources such as rechargeable lithium coin cell batteries, or primary batteries as shown in Figure 3. To accommodate a variety of battery chemistries and maximum voltages the VSTORE/VCAP over and undervoltage thresholds are user programmed to one of four voltage ranges using the VSTORE/VCAP select pins SS1 and SS2, according to Table 2. Table 2. VSTORE Voltage Selection PRI SS1 SS2 VSTORE/ VCAP OV VSTORE/ VCAP UV 0 0 0 0 0 4V 2.78V Li Carbon VCC 2.9V 1.9V 2x Rechargeable NiMH 0 VCC 0 VCC 0 3V 2.15V Rechargeable Li Coin Cell VCC 4V 3V Li Polymer/Graphite VCC 0 0 4.2V 2.1V Primary, Non-Rechargeable BATTERY TYPE 3106f 18 For more information www.linear.com/LTC3106 LTC3106 Operation L1 SW1 RECHARGEABLE BACKUP SOURCE + SW2 VSTORE LTC3106 VAUX ENVSTR C1 + C2 3106 F03 Figures 3 and 4 show an additional Schottky diode (D1) from SW2 to VAUX. When charging is enabled (PRI = GND) the addition of a Schottky diode from SW2 to VAUX is necessary to prevent a VOUT regulation error caused by the small parasitic output current resulting from the LTC3106 charging the secondary battery on VSTORE/VCAP. The additional diode allows for some inrush current to the VAUX capacitor C3 from either input source that would have otherwise been blocked by the AUXSW. Figure 5 shows an alternate Schottky diode configuration with two additional external components, Q1 and C4, that will still eliminate the VOUT regulation error but will also significantly reduce the inrush current. L1 SW1 SW2 LTC3106 + INPUT SOURCE ENVSTR DIS C1 + D1 VSTORE VAUX C3 VCAP PRI VIN C2 + INPUT SOURCE If secondary battery charging is enabled (PRI = GND) with both the output and VAUX voltages in regulation, available input power will be diverted to VSTORE/VCAP to trickle charge the backup power source with a 30mA typical current limit. Overcharging of the input source is prevented by the upper limit threshold setting. RECHARGEABLE LOW CAPACITY SOURCE VSTORE ENVSTR C1 VCAP Figure 3. High Capacity Battery Configuration (Shown with VSTORE Enabled) EN SW1 SW2 LTC3106 BACKUP SOURCE PRI VIN 3106 F04 Figure 4. Low Capacity Battery Configuration (Shown with VSTORE Disabled, ENVSTR Tied to Ground) 0.1µF Q1 D1 C3 VCAP INPUT SOURCE D1 L1 + VAUX 4.7µF PRI VIN C2 3106 F05 Figure 5. Rechargeable Battery Configuration with Inrush Current Limiting Low Capacity Secondary Battery and True Isolation For very low capacity batteries an isolation switch between VSTORE and VCAP provides for true input source isolation and near zero current draw (<1nA) on VSTORE. As shown in Figure 4, simply connect VCAP to a bulk capacitor and VSTORE to the isolated source. Tie ENVSTR to ground to isolate VSTORE. Although adequate for most low capacity sources such as solid state or small Li-Ion Polymer batteries, the current available to the output from VSTORE in this configuration will be reduced. To enable VSTORE as an input and prevent a significant increase in the quiescent current, it is recommended that ENVSTR terminate to VSTORE or to a voltage greater than VSTORE. Primary Battery The LTC3106 PRI input allows the user to disable secondary battery features such as trickle charging on VSTORE so that a primary battery may be used in the absence of sufficient power from the harvested source on VIN. The SW2 to VAUX Schottky diode is NOT required or recommended with the primary function enabled. With PRI tied to VCC, the VSTORE input voltage range ignores the state of the SS1 and SS2 pins and operates over the wide voltage range of 2.1V to 4.3V. To use the highest peak current capability VSTORE should be tied to VCAP in this configuration. To start the LTC3106 from VSTORE/VCAP, VSTORE/VCAP must be greater than 2.1V nominally. During an output short (VOUT < 1.1V) a small VSTORE reverse current of 20µA (typical) will be 3106f For more information www.linear.com/LTC3106 19 LTC3106 Operation present. If an extended duration output short is expected, protection for the primary battery should be considered. Start-Up The LTC3106 will start up from either input voltage source but gives priority to VIN. The AUX output is initially charged with the synchronous rectifiers disabled. Once VAUX has reached its terminal voltage the output voltage is then also charged asynchronously until VOUT reaches approximately 1.2V. The converter then leaves the asynchronous mode in favor of a more efficient synchronous start-up mode until VOUT is in regulation and the part enters normal operation. It is normal for the output voltage to rise as VAUX is charging. The AUXSW switch and the SWDI switch are in parallel so even when switched off there is still some asynchronous body diode conduction to the output. The rate at which this occurs is related to the VAUX/VOUT output capacitor ratio and operating conditions at start-up (i.e., any static load on VOUT). A minimum 10:1 ratio of VOUT to VAUX cap is recommended to allow for proper start-up. Starting from Very Low Current Input Sources Many solar cells that are optimized for indoor use have very low available power at low light levels and therefore very low output current, often less than 100µA at 200Lux. If the LTC3106 is to start up using only a weak source on VIN and with no back up battery on VSTORE the input capacitance must be sized larger than that for normal operation. Although dependent on the specific operating conditions for the application, in general, starting from low current sources on VIN at low light levels alone will require larger input capacitances than those calculated using the CVIN equation in the VIN and VOUT Capacitor Selection section. For example if the LTC3106 application in Figure 14 needs to start from the AM-1454 solar cell without the benefit of a battery on VSTORE, the required input capacitance increases from 470µF to 2.2mF minimum. If a battery is connected to VSTORE but is disabled by bringing ENVSTR low and is therefore not used to start the LTC3106, the input source on VIN needs to have an output current equal to or greater than 100µA (typ) regardless of the input capacitor size for the internal VCC decision circuit to run properly during start up. If the input source has less than a 100µA capability, startup could stall until more input current is available from the source or until the VSTORE battery is enabled. The 100µA limitation also applies where the LTC3106’s output is used to charge a battery or a large super capacitor. For typical applications where the input capacitance is greater than the output capacitance the 100µA limitation does not apply. Operating from a Low Power VIN Controlling the minimum input voltage is essential when using high impedance or intermittent input sources. The LTC3106 has several options for VIN voltage control during start-up and during normal operation. If a valid VSTORE voltage exists or if VAUX is in regulation, there are several LTC3106 configurations allowing accurate control at lower input voltages on VIN. The accurate RUN comparator can be used to control the VIN turn-on threshold at any arbitrary voltage equal to or above 600mV as discussed in the Accurate RUN Pin section of this data sheet. The 300mV UVLO on VIN could also be used to maintain VIN but is fixed at the 300mV threshold. If a higher sleep current can be tolerated, the MPP pin can be used to control VIN at any arbitrary threshold above 300mV. These latter two methods of controlling VIN are discussed in later sections of the data sheet. Even if no other input source is present (VSTORE/VCAP disabled, not used or too low), a crude VIN comparator will control VIN during start-up. If the RUN pin is tied to VIN or held above the RUN enable threshold (>0.4V typ) the LTC3106 has a typical start-up voltage of 0.85V with input currents as low as 15µA or ~12µW of input power. If the source impedance is high enough to cause VIN to drop below the VIN comparator threshold, start-up is terminated until the input capacitance is again charged to approximately 0.85V. Operation continues in this manner until start-up is complete. Input source impedance due to the source itself or due to the input source’s expected environmental conditions determine the required size of the input capacitance on VIN to facilitate a successful start-up. Recommendations are presented in the Input Capacitor Selection and Typical Applications sections of this document. 3106f 20 For more information www.linear.com/LTC3106 LTC3106 Operation Normal Operation Boost Mode When VAUX is in regulation (~5.2V) and VOUT is greater than 1.2V typical, the converter will enter normal operation. When VIN < VOUT – 300mV, the LTC3106 operates in boost or step-up mode. Referring to Figure 6 when VOUT falls below the programmed regulation voltage, switches A and C are turned on (VIN is applied across the inductor) and current is ramped until IPEAK is detected. When this occurs, C is turned off, D is turned on and current is delivered to the output capacitor (VIN – VOUT is applied across the inductor). Inductor current falls when D is on, until an IVALLEY is detected. Terminating at IVALLEY results in an increased load current capability for a given peak current. This AC then AD switch sequence is repeated until the output is pumped above the programmed regulation voltage, a final IVALLEY is detected, and the part returns to sleep mode. Always prioritizing VIN over VCAP, the integrated PowerPath control circuitry provides seamless transition between input sources as needed to maintain regulation of the output voltage and to periodically recharge VAUX. An accurate comparator is used to monitor the output voltage as it continues to charge to one of the user selected fixed output voltage values. If VOUT is above this voltage value no switching occurs and only quiescent current is drawn from the power source (sleep mode). When VOUT drops below the fixed output voltage the LTC3106 “wakes up”, switching commences, and the output capacitor is again charged. The value of the output capacitor, the load current, input source and the output voltage comparator hysteresis (~1%) all determine the number of current pulses required to pump up the output capacitor before the part returns to sleep. Normalized input and output voltages in the various modes as well as typical inductor current waveforms are shown in Figure 6. Only VIN is shown but the VSTORE/VCAP power path have the same architecture. Regions of the current waveforms where switches A and D are on provide the highest efficiency since energy is transferred directly from the input source to the output. VIN Buck Mode When VIN > VOUT + 700mV, the LTC3106 operates in buck or step-down mode. At the beginning of a buck mode cycle (Figure 6 right side) switches A and D are turned on (VIN – VOUT is applied across the inductor), current is delivered to the output and ramped up until IPEAK is detected. When this occurs, A is turned off, B is turned on and inductor current falls (–VOUT across the inductor) until an IVALLEY is detected. This AD then BD switch sequence is repeated VOUT VIN VOUT A D1 VIN L SW1 B SW2 C IMAX IPEAK tOFF tOFF tOFF BD AC AD BD AC BUCK-BOOST MODE AD IVALLEY IZERO AC AD AC AD BOOST MODE AC AD BD AD BD AD BD BUCK MODE 3106 F06 Figure 6. Operating Voltage and Current Waveforms 3106f For more information www.linear.com/LTC3106 21 LTC3106 Operation until the output is pumped above its regulation voltage, a final IVALLEY is detected, and the part returns to sleep mode. Buck-Boost Mode If (VOUT – 700mV) < VIN < (VOUT + 300mV), the LTC3106 operates in 4-switch step-up/step-down mode. Returning to Figure 6 (center) when VOUT falls below its regulation voltage, switches A and C are turned on and current is ramped until IPEAK is detected. As with boost mode operation, C is then turned off, D is turned on and current is delivered to the output. When A and D are on, the inductor current slope is dependent on the relationship between VIN, VOUT, and the RDS(ON) of the switches. In 4-switch mode, a tOFF timer is used to terminate the AD pulse. Once the tOFF timer expires, switch A is turned off, B is turned on, inductor current is ramped down and VOUT is applied across the inductor until IVALLEY is detected. This sequence is repeated until the output is regulated, BD switches are turned on, and a final IVALLEY is detected. Anti-cross conduction circuitry in all modes ensures the P-channel MOSFET and N-channel MOSFET switch pairs (A and B or D and C) are never turned on simultaneously. Note all three operational modes function the same if powering from VSTORE/VCAP when VIN is not available. Simply consider VIN in the preceding paragraphs as VSTORE/VCAP. Undervoltage Lockout (UVLO) and Very Low VIN Operation Maximum Power Point Operation As an alternative to using an external divider on the RUN pin (or for maximum power point thresholds below the 600mV RUN pin threshold) the maximum power point control circuit allows the user to set the optimal input voltage operating point for a given power source. The MPP circuit hysteretically regulates the average VIN voltage to the MPP threshold. When VIN is greater than the MPP voltage, input power is taken from VIN to supply the load. If the VIN power source does not have enough power for the load it will decrease. When VIN is less than the MPP threshold voltage the input transitions to VSTORE/VCAP if available. VIN power may then recharge the input capacitor voltage and as it rises above the MPP threshold the process repeats. VIN MPP regulation is then maintained using this “burst” technique. If VSTORE is disabled or in undervoltage, no switching occurs until VIN again rises above the MPP threshold and only quiescent current is drawn from the power source (same as sleep mode). To set the MPP threshold a 1.5µA (typical) source current is provided at the MPP pin. An external resistor to ground allows an arbitrary MPP threshold voltage setting. See Figure 7. MPP FUNCION ENABLED MPP FUNCION DISABLED LTC3106 IQ = 10.5µA LTC3106 IQ = 1.5µA MPP R3 There is an undervoltage lockout (UVLO) circuit within the LTC3106 to allow very low voltage VIN operation. If the LTC3106 is configured so that the RUN pin is externally driven to a voltage greater than the 600mV accurate RUN threshold, the VIN UVLO function allows the input voltage to remain viable as an input source down to ~250mV. Below this threshold VIN is disabled and the input source will transition to VSTORE/VCAP, assuming VSTORE/VCAP is within its programmed range, until VIN rises above ~300mV, where input power again transitions to VIN. The VIN input is always given priority over the VSTORE/ VCAP input if VIN is viable. VCC MPP 1.2µA 3106 F07 Figure 7. MPP Configurations Note that when the MPP function is used the nominal quiescent current increases from 1.5µA (typical) to 10.5µA (typical). To disable the MPP feature and eliminate the additional IQ, simply tie MPP to VCC. PGOOD Comparator The LTC3106 provides an open-drain PGOOD output that pulls low if VOUT falls more than 10% (typical) below its programmed value. When VOUT rises to within 8% (typical) of its programmed value, the internal PGOOD pull-down 3106f 22 For more information www.linear.com/LTC3106 LTC3106 Operation will turn off and PGOOD will go high if an external pullup resistor has been provided. An internal deglitch filter prevents nuisance trips of PGOOD due to short transients (<15µs typically) on VOUT. Note that PGOOD can be pulled up to any voltage, as long as the absolute maximum rating of 6V is not exceeded, and as long as the maximum sink current rating is not exceeded when PGOOD is low. The PGOOD pin is not actively pulled low in shutdown. If pulled high the PGOOD pin will float high and will not be valid until 3.5ms after the part is enabled. Power Adjust Feature The LTC3106 ILIMSEL option enables a feature that maximizes efficiency at light load while providing increased power capability at heavy load by adjusting the peak and valley of the inductor current as a function of load. Lowering the peak inductor current for either input source at light load optimizes efficiency by reducing conduction losses in the internal MOSFET switches. As the load increases, the peak inductor current is automatically increased to a maximum of 650mA for VIN and 150mA for VSTORE/VCAP. At intermediate loads, the peak inductor current may vary from 90mA to 650mA. Figure 8 shows an example of how the inductor current changes as the load increases. COUT = 47µF, ILIMSEL = HI IL 200mA/DIV ILOAD 100mA/DIV 100µs/DIV 3106 F08 Figure 8. Inductor Current Changing as a Function of Load The valley of the inductor current is automatically adjusted as well to maintain a relatively constant inductor ripple current. This keeps the switching frequency relatively constant with load. The “burst” frequency (how often the LTC3106 delivers a burst of current pulses to the load) is determined by the internal hysteresis (output voltage ripple), the load current and the amount of output capacitance. All Burst Mode operation, or hysteretic converters, will enter the audible frequency range when the load is light enough. However, due to the low peak inductor current at light load, circuits using the LTC3106 do not typically generate any audible noise. Note that the power adjust feature is overridden by the MPP function. To maximize efficiency for very high impedance input sources, low frequency pulsed load or low load current applications, the power adjust feature may be disabled using the ILIMSEL pin keeping the peak currents limited to 90mA. See Table 3 for ILIMSEL configurations. Table 3. Current Limit Adjustment ILIMSEL VIN PEAK ILIMIT (mA) VSTORE PEAK ILIMIT (mA) 0 100 100 VCC 650 170 Energy Storage Harvested energy can be stored on the input capacitor, the output capacitor or if enabled, on the backup storage element on VSTORE. The wide input voltage range takes advantage of the fact that energy storage on the input capacitor is proportional to the square of the capacitor voltage. After the output voltage is brought into regulation any excess energy is stored on the input capacitor and its voltage increases. If VSTORE charging is enabled (PRI pin grounded) excess energy will first be used to recharge the backup power source before storing energy on the input capacitor. The VOUT capacitor should be a minimum of 47μF. A larger output capacitor can be used if lower peak to peak output voltage ripple is desired. A larger output capacitor will also improve load regulation on VOUT but will result in higher peak currents than necessary at light load lowering the light load efficiency. 3106f For more information www.linear.com/LTC3106 23 LTC3106 Applications Information A standard application circuit for the LTC3106 is shown on the front page of this data sheet, although the LTC3106 can be configured to work from a variety of alternative energy and backup battery sources. The appropriate selection of external components is dependent upon the required performance of the IC in each particular application. This section of the data sheet provides some basic guidelines and considerations to aid in the selection of external components and the design of the applications circuit, as well as a few other application circuit examples. VSTORE/VCAP Capacitor Selection If there is insufficient power on VIN, the VSTORE/VCAP input carries the full inductor current and provides power to internal control circuits in the IC. To minimize VSTORE voltage ripple and ensure proper operation of the IC, a low ESR bypass capacitor with a value of at least 4.7μF should be located as close to the VCAP pin as possible. The traces connecting this capacitor to VCAP and the ground plane should be made as short as possible. In cases where the series resistance of the battery is high or the LTC3106 is powered by long traces or leads, a larger value bulk input capacitor may be required and is generally recommended. In such applications a 47μF to 100μF low ESR electrolytic capacitor in parallel with a 1μF ceramic capacitor generally yields a high performance, low cost solution. Note that if there is sufficient power on VIN only capacitor leakage current and shutdown current will be drawn from the VSTORE/VCAP source. When using the Shelf Mode feature, the VSTORE pin should be isolated from the VCAP pin and no capacitor is needed on the VSTORE pin. Instead the bypass capacitor should be located only on the VCAP pin. be intermittent, such as in energy harvesting applications, the total VIN capacitor value will be selected to optimize the use of the harvested source and will typically be greater than 100μF. In energy harvesting applications the VIN and VOUT capacitors should be selected to optimize the use of the harvested source. Input capacitor selection is highly important if the LTC3106 must start from a, high source resistance system on VIN. When using bulk input capacitors that have high ESR, a small valued parallel ceramic capacitor should be placed between VIN and GND as close to the converter pins as possible. After VAUX and the output voltage are brought into regulation any excess energy is stored on the input capacitor and its voltage will increase. Care should be taken to ensure the open-circuit voltage of the harvested source does not exceed or is appropriately clamped to the maximum operating voltage VIN and that the input capacitor is rated for that voltage. For pulsed load applications, even low power pulsed load applications such as Eterna® BLE, ZigBee as well as other proprietary low power RF protocols, the input capacitor should be sized to store enough energy to provide output power for the duration of the load profile. If enough energy is stored so that VIN does not reach the chosen falling threshold during a load transient then the VSTORE/ VCAP current will be minimized thereby maximizing battery life. Spacing load transients so that the average power required to service the application is less than or equal to the power available from the energy harvesting source will also greatly extend the life of the battery. The following equation can be used to size the input capacitor to meet the power requirements of the output for the desired duration: VIN and VOUT Capacitor Selection The LTC3106 has no maximum capacitance limitation on VIN or VOUT but there is a slew rate limitation on VIN that drives the need for a minimum input capacitance. Refer to the plot of Maximum Slew Rate vs Input Voltage in the Typical Performance Characteristics section. For general applications where the input source has a low impedance and relatively high output power, a minimum 22μF ceramic capacitor is recommended between VIN and GND. In applications where the input has a high impedance and may C VIN = (2/η• VOUT • ΣInTn ) (µF ) (V INOV 2 – VINUV 2 ) Here η is the average efficiency of the converter over the input voltage range and VIN is the input voltage when the converter begins to switch. Typically VIN(OV) will be the selected input voltage rising threshold. VIN(UV) is the VIN(OV) minus the hysteresis voltage. ∑InTn is the area under each of the load pulses for given load profile. This equation may overestimate the input capacitor necessary. It may be 3106f 24 For more information www.linear.com/LTC3106 LTC3106 Applications Information acceptable to allow the load current to deplete the output capacitor all the way to the lower PGOOD threshold. The equation also assumes that the input source charging has a negligible effect during this time. Example uses of this equation to size input capacitors are included in the design examples later in this section. The duration for which the regulator sleeps depends on the load current and the size of the VOUT capacitor. The sleep time decreases as the load current increases and/or as the output capacitor decreases. The VOUT capacitor should be a minimum of 47μF. A larger output capacitor can be used if lower peak-to-peak output voltage ripple is desired. A larger output capacitor will also improve load regulation on VOUT. Multilayer ceramic or low ESR electrolytic capacitors are both excellent options. Proper sizing of the input capacitor to optimize energy storage at the input utilizes the potential for higher input voltages and higher efficiency. Ultimately the output current is limited by what the converter can supply from its input. If a larger peak transient load needs to be serviced, the output capacitor should be sized to support the larger current for the duration of the load transient by the following: COUT ≥ILOAD • tPULSE VDROOP COUT is the output capacitor value (µF) required, ILOAD is the peak transient load current (mA), tPULSE is the duration of that transient (ms) and VDROOP is the amount of voltage droop the circuit can tolerate (both in V). For many of the LTC3106 applications, the input capacitor values can be quite large (>1mF). A list of high value storage capacitor manufacture’s is listed in Table 4. For larger bulk output capacitors an additional low effective series resistance (ESR) output capacitor of 10μF should be added and connected as close to the IC pin as possible. Regardless of its value, the selected output capacitor must be rated higher than the voltage selected for VOUT by OS1 and OS2. Likewise the selected input capacitor must be rated higher than the open-circuit voltage of the VIN source. Table 4. Recommended Bulk Storage Capacitor Vendors VENDOR PART AVX BestCap Series TAJ, TPS Series Tantalum Vishay 595D Series (Tantalum) 153 CRV (Aluminum, Low Leakage) 150 CRZ (Aluminum, Low Leakage) 196 DLC (Double Layer Aluminum) Illinois Capacitor RKR Series (Aluminum, Low Leakage) DCN Series Cooper Bussman KR Series KW Series PA, PB, PM, PH Series Cap-XX G Series (Dual Cell) H Series (Dual Cell) VCC Capacitor Selection The VCC output of the LTC3106 is generated from the greatest of VIN, VCAP, VAUX or VOUT. A low ESR 0.1μF capacitor should be used. The capacitor should be located close to the VCC pin and through the shortest ground traces possible. VAUX Capacitor Selection A minimum 2.2µF low ESR capacitor must be used to decouple VAUX although 4.7μF is more typical for many applications. Smaller capacitor sizes help reduce VOUT ripple especially at high load currents while larger capacitor sizes improve start-up at low output voltages. The capacitor should be located as close to the VAUX pin as possible. As mentioned in the operations section the AUX D switch and the VOUT D switch are in parallel. Asynchronous diode conduction will occur when either VAUX or VOUT is being serviced by the buck/boost circuitry. For this reason it is recommended to keep a 10:1 ratio of VOUT to VAUX capacitor to ensure a proper start-up with low voltage, high impedance sources. Under most load conditions the output voltage will be maintained normally although under true zero load conditions (<500nA) the parasitic current from VAUX to VOUT could force VOUT to regulate up to 5% higher than typical. 3106f For more information www.linear.com/LTC3106 25 LTC3106 Applications Information Use of Ceramic Capacitors To minimize losses in low power systems all capacitors should have low leakage current. Ceramic capacitors are recommended for use in LTC3106 applications due to their small size, low ESR and low leakage currents. However, many ceramic capacitors intended for power applications experience a significant loss in capacitance from their rated value as the DC bias voltage on the capacitor increases. It is not uncommon for a small surface mount capacitor to lose more than 50% of its rated capacitance when operated at even half of its maximum rated voltage. This effect is generally reduced as the case size is increased for the same nominal value capacitor. As a result, it is often necessary to use a larger value capacitance or a higher voltage rated capacitor than would ordinarily be required to actually realize the intended capacitance at the operating voltage of the application. X5R and X7R dielectric types are recommended as they exhibit the best performance over the wide operating range and temperature of the LTC3106. To verify that the intended capacitance is achieved in the application circuit, be sure to consult the capacitor vendor’s curve of capacitance versus DC bias voltage. PGOOD Output The PGOOD output can also help with power management. PGOOD transitions high the first time the output reaches regulation and stays high until the output falls to 92% of the regulation point. PGOOD can be used to trigger a system load. For example, a current burst could begin when PGOOD goes high and would continuously deplete the output capacitor until PGOOD went low. Note the PGOOD pin will remain high if the output is still within 92% of the regulation point, even if the input falls below the lower UVLO threshold. Inductor Selection Low DCR power inductors with values between 4.7μH and 10μH are suitable for use with the LTC3106. Inductor vendor information can be found in Table 5. For most applications, a 10μH inductor is recommended. In applications where the input voltage is very low, a larger value inductor can provide higher efficiency and a lower start-up voltage. In applications where the input voltage is relatively high (VIN > 0.8V), smaller inductors may be used to provide a smaller overall footprint. In all cases, the inductor must have a low DCR and a saturation current rating greater than the highest typical peak current limit setting as listed in the Electrical Characteristics table. If the DC resistance of the inductor is too high, efficiency will be reduced and the minimum operating voltage will increase. Note the inductor value will have a direct effect on the switching frequency. Table 5. Inductor Vendor Information VENDOR PART Coilcraft www.coilcraft.com EPL2014, EPL3012, EPL3015, LPS3015, LPS3314, XFL3012 Coiltronics www.cooperindustries.com SDH3812, SD3814, SD3114, SD3118 Murata www.murata.com LQH3NP, LQH32P, LQH44P Sumida www.sumida.com CDRH2D16, CDRH2D18, CDRH3D14, CDRH3D16 Taiyo-Yuden www.t-yuden.com NR3012T, NR3015T, NRS4012T, BRC2518 TDK www.tdk.com VLS3012, VLS3015, VLF302510MT, VLF302512MT Toko www.tokoam.com DP3015C, DB3018C, DB3020C, DP418C, DP420C, DEM2815C, DFE322512C, DFE252012C Würth www.we-online.com WE-TPC 2813, WE-TPC 3816, WE-TPC 2828 Maximum Power Point Threshold Configuration There are two methods for maintaining the maximum power point of an input source on VIN. Already discussed in this data sheet is a resistive divider on the RUN pin monitoring VIN. This is useful for >600mV MPP set points. The LTC3106 also has a dedicated MPP function that can be used over the full input voltage range as well as input voltages between the UVLO and RUN pin thresholds. Note that the LTC3106 IQ increases from 1.6µA (typ) to 10.6µA (typ) if the MPPC pin functionality is enabled. The MPP circuit hysteretically controls VIN by setting a lower voltage threshold on the MPP pin. If VIN drops below the MPP threshold the converter will stop drawing power from VIN and force a sleep signal. If VSTORE is within the proper operating range, the output power will then be taken from VSTORE. If however there is not a valid 3106f 26 For more information www.linear.com/LTC3106 LTC3106 Applications Information backup source or if the ENVSTR is low the LTC3106 will go to sleep and no power will be available to VOUT until VIN charges the input capacitor voltage above the MPP threshold. If more power is available at VIN than is needed to supply VOUT, VIN could rise above the MPP threshold to the open-circuit voltage of source. This is normal as long as the open-circuit voltage is below the maximum allowed input voltage. The MPP pin voltage is set by connecting a resistor between the MPP pin and GND, as shown in Figure 4. The MPP voltage is determined by the equation: The application circuit in Figure 9 shows the LTC3106 interfaced with the AM-1816 solar cell supplemented with a CR2032 primary battery configured to deliver power to a pulsed load output. Though an energy harvesting system can eliminate the need for batteries, it also serves to supplement and increase battery life. When enough ambient energy is available the battery is unloaded and is only used when the ambient source is inadequate, not only extending battery life but improving reliability. Even when battery use is necessary, the PRI pin configures the VSTORE input for use of a primary battery, here the CR2032, extending the input voltage range, thereby increasing use of the available capacity than would be possible with a direct battery-MCU connection. VMPP = 1.5μA • RMPP (MΩ) Disable the MPP function by tying the MPP pin to VCC. Design Example 1: Photovoltaic or Solar Energy Harvesting with Primary Battery Backup The main input voltage, VIN, of the LTC3106 is designed to accommodate high impedance solar cells over a wide voltage range. Solar cells are classified according to their output power level, material employed (crystal silicon, amorphous silicon, compound semiconductor) and application space (indoor or outdoor lighting). Sanyo Electric’s Amorton product line (a subsidiary of Panasonic) offers a variety of solar cells for various light conditions (For typical light conditions see Table 6) and power levels as well the ability to customize cells for specific application size and shapes. An additional list of companies that manufacture small solar cells (also referred to as modules or solar panels) suitable for use with the LTC3106 is provided in Table 7. In traditional battery hyp. only wireless nodes the main control unit (MCU) is connected directly to the battery. Several factors contribute to reduced battery capacity in these applications. Typically these wireless systems poll the node at a very low frequency with long low power inactive periods and occasional high current bursts when communicating with the node. The peak current during the pulsed load is much greater than the nominal drain current given by the battery manufacturer reducing capacity beyond that specified at the typical static drain current. Further, the usable input voltages for most MCUs (2V min typ) limit the usable capacity. 10µH 3V CR2032 + LITHIUM COIN CELL 47µF SW1 VSTORE VCAP ENVSTR SW2 VAUX 2.2µF LTC3106 VIN THRESHOLD = 3.8V MIN + VOC = 4.9V SANYO ISC = 82µA AM1816 100µF 6.3V ×3 10M 10µF 47µF PGOOD VIN 2M 365k 3.3V, ~200µW VOUT VIN 0.01µF RUN VCC PRI ILIMSEL GND MPP OS1 OS2 SS1 SS2 VDD Tx EN GND VCC 3106 F09 Figure 9. Solar Harvester with Primary Battery Backup 3106f For more information www.linear.com/LTC3106 27 LTC3106 Applications Information 1.0 Table 6. Typical Light Conditions 0.9 Meeting Room 200 0.8 Corridor 200 0.6 Office Desk 400 to 700 Lab 500 to 1000 Outdoors (Overcast) 1000 to 2000 Outdoors (Clear) >2000 IPANEL (mA) ILLUM. (Lux) http://panasonic.net/energy/amorton/en/ PowerFilm http://www.powerfilmsolar.com/ G24 Power http://www.gcell.com/ SolarPrint http://www.solarprint.ie/ Alta Devices http://www.altadevices.com 1000 LUX 0.5 500 LUX 0.4 0.3 200 LUX 0.1 Table 7. Small Photovoltaic Panel Manufacturers Sanyo Sanyo 1816 1800 LUX PPANEL (mW) LOCATION 0 0 0.7 1.5 2.2 3.0 3.7 VPANEL (V) 4.4 5.2 5.9 3106 F10 Figure 10. Measured I-V and P-V Curves Under Variable Light Conditions The I-V and P-V curve for the AM-1816 panel is shown in Figure 10. The maximum power from the cell (PMAX) changes with light level but the voltage at PMAX changes only slightly. The VIN threshold voltage in this application example is set to equal the voltage at PMAX using the resistive divider on the RUN pin. 4.2V is chosen for the VIN(OV) set point so that it is slightly below. With internal hysteresis the VINUV is then 3.8V so the average VIN voltage of ~4V is at the maximum power point from the manufacturer I-V and P-V data on the AM-1816 solar cell. Note the RUN pin resistive divider will add a VIN dependent load on the input source. The divider current would be equal to: IINDIV(STATIC) 4V = 1.6µA (2.21M+ 432k) In this application the load is a low power proprietary RF profile (Figure 11). The regions of operation are described, output and power losses are tabulated and the peak levels for each are given in Table 8. The total average output power needed in this application can be calculated to be 191µW. Table 8. Application Load Profile Power Budget for Figure 11 REGION INTERVAL Tn CHARGE InTn DUTY CYCLE (ms) (µC) (%) INTERVAL MCU FUNCTION PEAK CURRENT In (mA) Region 1 Wake 0.3 1 0.3 0.1 INTERVAL OUTPUT POWER (mW) 1.0 LTC3106 POWER AVERAGE LOSS (FROM OUTPUT CURVES) POWER (µW) (mW) 1 0.2 LTC3106 AVERAGE POWER LOSS (µW) 0.2 Region 2 Pre-Processing 8 0.6 4.8 0.1 26.4 16 3 1.8 Region 3 Rx/Tx 20 1 20 0.1 66.0 66 5 5.0 Region 4 Processing 8 0.5 4 0.0 26.4 13 3 1.5 Region 5 Rx/Tx 20 1 20 0.1 66.0 66 5 5.0 Region 6 Sleep/Idle 0.001 1000 1 99.5 0.003 3 0.02 19.9 Total Period: 1004ms Total Avg Power: 165µW Total Avg. Power Loss: 37µW 3106f 28 For more information www.linear.com/LTC3106 LTC3106 Applications Information CURRENT ACTIVE ACTIVE ACTIVE INACTIVE/ SLEEPING INACTIVE/ SLEEPING ACTIVE INACTIVE/ SLEEPING TA TB TIME CURRENT IPK2 IPK1 IBACK REGION 1 T1 REGION 2 REGION 3 T2 REGION 4 T3 REGION 5 T4 REGION 6 T5 T6 TIME 3106 F11 Figure 11. Application Load Profile for Schematic in Figure 8 The total average LTC3106 power loss over the same regions of operation for the load profile is 37µW. The divider load adds an additional 5µW of input power loss for a total input power requirement of 207µW. The calculated average efficiency, including the resistive divider is then η = 165µW/207µW which is 80%. The available power from the AM-1816 at 200lux is about 400µW. With a converter efficiency of about 80% the 400µW will power the total 207µW average load with some margin. If the light conditions become less favorable the available input power may drop below that needed to maintain the output voltage. The LTC3106 configuration in Figure 9 will operate with VIN in “hiccup” mode turning on as VIN increases above 4.2V and turning off if VIN droops below 3.8V. With VIN off, power is then taken from VSTORE until VIN recovers and increases above the 4.2V threshold. If the light conditions become more favorable VIN will rise to the open-circuit voltage of the harvested source. Note if the open-circuit voltage of the harvested source will exceed the maximum voltage rating, an appropriate clamp should be added to prevent damage to the LTC3106. Figure 10 shows the open-circuit voltage of the AM-1816 can be greater than 5V. If full light is expected, a low reverse leakage current Zener diode is recommended to clamp VIN. The DZ23, AZ23 and GDZ series with a Zener voltage of 4.7V or 5.1V are a good choice. 3106f For more information www.linear.com/LTC3106 29 LTC3106 Applications Information To optimize use of the harvested source and increase the battery life of the backup source it is important to size the input capacitor to handle the average power load for the load profile at the lowest light level. Referring again to Table 8 to sum the required charge for the load and using the input capacitor sizing equation: C VIN = (2/η• VOUT • ΣlnTn ) (µF ) (V IN(OV) 2 – VIN(UV)2 ) Peltier cells are available in a wide range of sizes and power capabilities, from less than 10mm square to over 50mm square. They are typically 2mm to 5mm in height. A list of Peltier cell manufacturers is given in Table 9. Table 9. Peltier Cell Manufacturers Micropelt www.micropelt.com CUI, Inc www.cui.com (Distributor) The average efficiency (η) with VIN = 4.2V and VOUT = 3.3V is 0.8. The VIN(OV) and VIN(UV) thresholds are already determined and ∑InTn can be found in the load profile table. CVIN is found to be 184µF. A single 220µF low leakage Tantalum chip capacitor could be used. For the lowest leakage solution and to add design margin 2× 100µF, 6.3V, ±10% ceramic capacitors are selected. If the VIN source is unavailable the primary battery on VSTORE will continue to supply the load. To offload the peak current load from the battery and minimize the effect of high peak currents degrading the rated battery capacity the lowest peak current setting on the LTC3106 is chosen. In addition, the VSTORE capacitor design should follow that of the VIN capacitor. Using the same method but replacing the OV and UV thresholds with the max and min VSTORE input voltages the value of the VSTORE capacitor is calculated to be 38µF. For design margin a low ESR 10V, 47µF ceramic capacitor is used. Design Example 2: Thermoelectric Harvesting from Peltier cell (TEG) with Rechargeable Battery Backup A Peltier cell (also known as a thermoelectric cooler) is made up of a large number of series-connected P-N junctions, sandwiched between two parallel ceramic plates. Although Peltier cells are often used as coolers by applying a DC voltage to their inputs, they will also generate a DC output voltage, using the Seebeck effect, when the two plates are at different temperatures. The polarity of the output voltage will depend on the polarity of the temperature differential between the plates. The magnitude of the output voltage is proportional to the magnitude of the temperature differential between the plates. In this manner, a Peltier cell is referred to as a thermoelectric generator (TEG). Fujitaka www.fujitaka.com/pub/peltier/english/thermoelectric_power.html Ferrotec www.ferrotec.com/products/thermal/modules Kryotherm www.kryothermusa.com Laird Technologies www.lairdtech.com Marlow Industries www.marlow.com Nextreme www.nextreme.com TE Technology www.tetech.com/Peltier-Thermoelectirc-Cooler-Modules.html Tellurex www.tellurex.com The low voltage capability of the LTC3106 design allows it to operate from a TEG with temperature differentials as low as 20°C, making it ideal for harvesting energy in many industrial applications in which a temperature difference exists between two surfaces or between a surface and the ambient environment. The application circuit in Figure 12 shows the LTC3106 interfaced with a TEG supplemented with a Li-ion rechargeable (secondary) battery, both configured to deliver power to a low power pulsed load output. With the RUN pin connected to VSTORE, the application circuit is configured to take advantage of the 300mV input voltage UVLO. In this configuration VIN will operate in “hiccup” mode turning on as VIN increases above 0.3V and turning off if VIN droops 50mV below 0.3V to maintain an average power to the output without allowing the input to fall to zero. Assuming a good battery voltage the output power will be supplied by the battery when the input voltage drops below the UVLO threshold and transition back to the input when the input charges up above the UVLO threshold. 3106f 30 For more information www.linear.com/LTC3106 LTC3106 Applications Information In addition to providing power to the output when the harvested power is not adequate, the secondary battery also provides a reservoir for excess harvested energy. If the output is in regulation harvested power is diverted to charge the secondary battery. The maximum charge voltage and low battery threshold are programmed by the SS1 and SS2 pins. In Figure 12 SS1 and SS2 are configured to provide a worst-case upper threshold of 4.16V and a worst-case low battery threshold of 2.88V (refer to Table 2). Charging of the secondary battery will terminate at the upper threshold to prevent excessive battery voltage. Since the ENVSTR pin is held high in this application, a prolonged absence of harvested power results in the output being maintained solely by the battery. With VCAP and VSTORE connected together, the battery will be disconnected from the internal power path at the low battery threshold to protect Li-Ion batteries from permanent damage due to deep discharge. A low ESR 10µF capacitor is used to decouple the VSTORE/VCAP pin. Similar to the previous design example the load profile is another low power proprietary RF profile (Figure 13). The RxTx rate of this load pulse is 2 seconds. The regions of operation are described, output and power losses are tabulated and the peak levels for each are given in Table 10. The total average output power needed in this application can be calculated to be 42µW. The total average LTC3106 power loss over the same regions of operation for the load profile is 31µW. The total input power requirement is 73µW. The calculated average efficiency, including the resistive divider is then η = 42µW/73µW which is 0.58. Although this may seem low it is important to realize the load current is quite low (2µA) a majority of the time (sleep/idle region) where the average power loss from the LTC3106 is only 20µW. To minimize use of the secondary battery and prolonging its long term lifetime, it is important to optimize the use of the harvested source by dimensioning the input capacitor to handle the average power load for the load profile at the lowest temperature differential. Referring again to 10µH PANASONIC NCR18650B LITHIUM ION CELL + 47µF SW1 VSTORE VCAP ENVSTR RUN SW2 VAUX ZLLS400 SCHOTTKY 2.2µF LTC3106 MARLOW TEG RC12-2.5-01LS WITH 40MM × 40MM × 35MM FINNED HEATSINK + 0.3V TO 3.5V + 470µF 6.3V ×2 3.3V, ~50µW VOUT VIN 10M 10µF 47µF PGOOD 0.01µF VCC PRI ILIMSEL GND MPP OS2 OS1 SS2 SS1 VDD Tx EN GND VCC VCC 3106 F12 Figure 12. TEG Harvester with Secondary Battery Backup 3106f For more information www.linear.com/LTC3106 31 LTC3106 Applications Information Table 11 to sum the required charge for the load and using the input capacitor sizing equation: C VIN = (2/η• VOUT • ΣlnTn ) (V INOV 2 – VINUV 2 ) The chosen capacitor should be rated for a voltage greater than the maximum open-circuit voltage of the harvested source and/or clamped to an appropriate voltage. If the open circuit TEG voltage is expected to be greater than the maximum rating of the input pin, it is recommended that a low reverse leakage current 4.7V or 5.1V Zener diode be used to clamp VIN. Table 11. Low Capacity Li-Ion and Thin Film Battery Manufacturers VENDOR PART CYMBET EnerChip CBC Series Infinite Power Solutions THINERGY MEC2000 and MEC100 Series GM Battery GMB and LiPo Series Large value storage capacitor manufactures are listed in Table 4. The application in Figure 12 uses 2× 470µF Tantalum chip capacitors. The average efficiency (η) with VIN(OV) = 0.3V and VIN(UV) = 0.25V, the input UVLO upper and lower thresholds respectively, and a VOUT of 3.3V is the already calculated η = 0.58. The ∑InTn can be found in the load profile table. CVIN is then found to be 973µF. At such low harvested power levels, the input capacitor values can be quite large. The available power from the TEG at the lowest temperature differential (dt = 20°C) is about 200µW, enough to power the total 42µW average load with some margin. If the conditions become less favorable the available input power may drop below that is needed at the output, VIN will drop below the UVLO threshold turning off VIN. With VIN off, power is then taken from VSTORE until VIN recovers and increases above the UVLO threshold. CURRENT IPK3 IPK2 IPK1 IBACK REGION 1 REGION 2 T1 REGION 4 REGION 3 T2 T3 REGION 5 T4 T5 TIME 3106 F13 Figure 13. Application Load Profile 3106f 32 For more information www.linear.com/LTC3106 LTC3106 Applications Information If conditions become more favorable the input capacitor will charge to a higher voltage terminating at the opencircuit voltage of the harvested source. When the output is idle under these conditions, excess energy is used to maintain the charge on the VSTORE battery. Any remaining excess energy will be stored on the input capacitor and VIN will rise to the open-circuit voltage of the harvested source. As already mentioned, if the open-circuit voltage of the harvested source will exceed the maximum voltage rating of the pin an appropriate clamp should be added to prevent damage to the LTC3106. Most MCUs, even low power wireless specific MCUs, still load the LTC3106 output with a small current. If, however, the load current will be less than 400nA the output regulation error can increase to 5% of the nominal output voltage depending on sleep period and the size of the output capacitor. Table 10. Application Load Profile Power Budget for Figure 11 INTERVAL PEAK REGION CURRENT In INTERVAL Tn CHARGE InTn DUTY CYCLE MCU FUNCTION (mA) (ms) (µC) (%) INTERVAL OUTPUT POWER (mW) 0.007 AVERAGE OUTPUT POWER (µW) LTC3106 POWER LOSS (FROM CURVES) (mW) LTC3106 AVERAGE POWER LOSS (µW) 7 0.2 20.0 Region 1 Sleep/Idle 0.002 2000 4 99.85 Region 2 Pre-Processing 1.7 0.6 1.02 0.03 56 2 3 0.9 Region 3 Tx 17 1 17 0.05 53.1 28 5 7.5 Region 4 Rx 4 0.5 2 0.02 13.2 3 3 1.2 Region 5 Post-Processing 1.7 1 1.7 0.05 5.6 3 5 1.5 Total Period: 2003ms Total Avg Power: 42.37µW Total Avg. Power Loss: 31µW 3106f For more information www.linear.com/LTC3106 33 LTC3106 Typical Applications The circuit in Figure 14 is a practical example of simple energy harvesting. The LTC3106 is powered from the USB bus power when the USB interface is connected for data transfer to a host. When the USB power is available VSTORE is disabled as an input, output power will come from VIN and charging of the battery will occur when VOUT and VAUX are in regulation. The battery may also be charged from ambient light on the Sanyo AM-1454 solar cell when the device used to collect data remotely, extending battery life and the time required between USB connections. Note that the D01 output from the monitor goes high and dials the LTC3106 peak current limit higher when USB power is available. harvester node and stored with a full charge for some time. When enabled the battery will supplement the harvested source and will be recharged with any surplus harvested energy. A list of thin-film battery manufacturers is listed in Table 11. The circuit in Figure 17 shows the LTC3106 configured to harvest solar energy when possible to prolong the time before battery service is necessary. The resistive divider on RUN sets the optimal minimum operating point for the solar cell on VIN. When available, harvested power on VIN supplements the power available from the primary battery extending the life of the battery. D1 10µH Figure 15 shows the LTC3106 as a simple dual input, 2.2V buck-boost converter. One input is from a 5V wall adaptor and the other from a 3V rechargeable lithium coin cell. Figure 15 also shows an example of the optional external inrush current limiting circuit to VAUX. Li RECHARGEABLE BATTERY 47µF VIN 0.1µF Q1 SW2 VAUX 2.2µF LTC3106 (3.7V TURN ON) 5V To take advantage of the very low discharge rate and long shelf life of low capacity thin film batteries the application in Figure 16 shows use of the Shelf mode functionality. An external switch allows the VSTORE pin to be disconnected from the external bypass capacitor on VCAP as well the internal power path and threshold detection circuitry thereby reducing battery discharge to VSTORE pin leakage plus the self-discharge of the battery itself. A factory “pre-charged” battery could then be assembled into the + SW1 VSTORE VCAP ENVSTR 2.2V (300mA) VOUT 22µF 10M 47µF PGOOD 2.21M RUN VCC 432k ILIMSEL MPP VCC OS2 SS1 PRI OS1 GND SS2 0.01µF 3106 F15 D1: DIODES INC ZLLS400 Q1: ZETEX ZMX61P03F Figure 15. 5V to 2.2V Converter with Rechargeable Battery Backup and Inrush Current Limiting 10µH + NiMH ×2 4.7µF SW1 VSTORE VCAP ENVSTR SW2 VAUX ZLLS400 SCHOTTKY 2.2µF MONITOR PROCESSING LTC3106 USB BUS POWER VOC = 2.4V ISC = 35µA VOUT VIN SANYO AM1454 + 4700µF 6.3V 2.21M 1.33M 10M 10µF VIN 0.1µF 3.3V (90mA/300mA) 47µF GND MPP OS1 SS2 OS2 SS1 MCU DISPLAY SENSOR(S) DATA EN DO1 PGOOD ILMSEL RUN VCC PRI VDD GND VCC USB POWER USB I/O 3106 F14 Figure 14. Portable Medical Device with Ambient Light Harvester or USB Powered Charging 3106f 34 For more information www.linear.com/LTC3106 LTC3106 Typical Applications 10µH THINERGY MEC201-10STR SW1 VSTORE + SHELF MODE 47µF ZLLS400 SCHOTTKY SW2 VAUX 4.7µF ENVSTR VCAP WIRELESS SENSOR NODE LTC3106 VIN THRESHOLD = 3.6V + POWERFILM MPT3.6-75 100µF 6.3V ×2 47µF 1M 1µF VDD EN 2.21M 0.01µF RUN VCC MPP OS2 OS1 PRI ILIMSEL SS2 SS1 GND MCU SENSOR(S) PGOOD VIN 432k 3.3V, (180µW) VOUT VIN GND VCC 3106 F16 Figure 16. Remote Outdoor Solar Powered Harvester with Thin Film Battery Backup 10µH 3.6V LITHIUM THIONYL + CHLORIDE AA CELL VCELL SANYO AM-1815 1µF 47µF SW1 VSTORE VCAP ENVSTR SW2 VAUX 4.7µF LTC3106 + 100µF 6.3V ×2 VIN 3V VOUT 1µF 47µF 1M PGOOD 2.21M 402k 0.1µF RUN VCC MPP OS2 OS1 PRI ILIMSEL SS2 SS1 VSUPPLY ANTENNA LNA_EN LTC5800 GND VCC 3106 F17 GND Figure 17. Extended Life Battery Powered Mote for Wireless Mesh Network 3106f For more information www.linear.com/LTC3106 35 LTC3106 Package Description Please refer to http://www.linear.com/product/LTC3106#packaging for the most recent package drawings. UDC Package 20-Lead Plastic QFN (3mm × 4mm) (Reference LTC DWG # 05-08-1742 Rev Ø) 0.70 ±0.05 3.50 ±0.05 2.10 ±0.05 1.50 REF 2.65 ±0.05 1.65 ±0.05 PACKAGE OUTLINE 0.25 ±0.05 0.50 BSC 2.50 REF 3.10 ±0.05 4.50 ±0.05 RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 3.00 ±0.10 0.75 ±0.05 1.50 REF 19 R = 0.05 TYP PIN 1 NOTCH R = 0.20 OR 0.25 × 45° CHAMFER 20 0.40 ±0.10 1 PIN 1 TOP MARK (NOTE 6) 4.00 ±0.10 2 2.65 ±0.10 2.50 REF 1.65 ±0.10 (UDC20) QFN 1106 REV Ø 0.200 REF 0.00 – 0.05 R = 0.115 TYP 0.25 ±0.05 0.50 BSC BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 3106f 36 For more information www.linear.com/LTC3106 LTC3106 Package Description Please refer to http://www.linear.com/product/LTC3106#packaging for the most recent package drawings. FE Package 20-Lead Plastic TSSOP (4.4mm) (Reference LTC DWG # 05-08-1950 Rev Ø) Exposed Pad Variation CC 6.40 – 6.60* (.252 – .260) 2.74 (.108) 2.74 (.108) 20 1918 17 16 15 14 13 12 11 6.60 ±0.10 2.74 4.50 ±0.10 (.108) 6.40 2.74 (.252) (.108) BSC SEE NOTE 4 0.45 ±0.05 1.05 ±0.10 0.65 BSC 1 2 3 4 5 6 7 8 9 10 RECOMMENDED SOLDER PAD LAYOUT 4.30 – 4.50* (.169 – .177) 0.09 – 0.20 (.0035 – .0079) 0.25 REF 0.50 – 0.75 (.020 – .030) NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS MILLIMETERS 2. DIMENSIONS ARE IN (INCHES) 3. DRAWING NOT TO SCALE 1.20 (.047) MAX 0° – 8° 0.65 (.0256) BSC 0.195 – 0.30 (.0077 – .0118) TYP 0.05 – 0.15 (.002 – .006) FE20(CC) TSSOP REV Ø 0413 4. RECOMMENDED MINIMUM PCB METAL SIZE FOR EXPOSED PAD ATTACHMENT *DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.150mm (.006") PER SIDE 3106f Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representaFor more information www.linear.com/LTC3106 tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. 37 LTC3106 Typical Application Simple Wide Input Voltage Buck-Boost Converter 10µH SW1 VSTORE VCAP ENVSTR VIN 0.6V TO 5V (0.85V TO START) SW2 VAUX 2.2µF LTC3106 VOUT 22µF 10M 47µF 1.8V 300mA PGOOD RUN 0.01µF VCC PRI ILIMSEL GND MPP OS2 OS1 SS2 SS1 VCC 3106 TAo2 Related Parts PART NUMBER DESCRIPTION COMMENTS LTC3103 15V, 300mA Synchronous Step-Down DC/DC Converter with Ultralow Quiescent Current VIN: 2.5V to 15V, VOUT(MIN) = 0.6V, IQ = 1.8μA, ISD = 1μA 3mm × 3mm DFN-10, MSOP-10 LTC3105 400mA Step-Up DC/DC Converter with Maximum Power Point Control and 250mV Start-Up VIN: 0.225V to 5V, VOUT(MIN) Adj. 1.5V to 5V, IQ = 24μA, ISD < 1μA, 3mm × 3mm DFN-12, MSOP-12 LTC3107 Ultralow Voltage Energy Harvester and Primary Battery Life Extender VIN = 0.02V to 1V, VOUT Tracks VBAT, VBAT = 2V to 4V, IQ = 80nA, VLDO = 2.2V, 3mm × 3mm DFN-10 LTC3108/LTC3108-1 Ultralow Voltage Step-Up Converter and Power Managers VIN: 0.02V to 1V, VOUT(MIN) Fixed 2.35V to 5V, IQ = 6μA, ISD < 1μA, 3mm × 4mm DFN-12, SSOP-16 LTC3109 Auto-Polarity, Ultralow Voltage Step-Up Converter and Power Manager VIN: 0.03V to 1V, VOUT(MIN) Fixed 2.35V to 5V, IQ = 7μA, ISD < 1μA, 4mm × 4mm QFN-20, SSOP-20 LTC4070 Li-Ion/Polymer Shunt Battery Charger System 450nA IQ, 1% Float Voltage Accuracy, 50mA Shunt Current 4.0V/4.1V/4.2V LTC4071 Li-Ion/Polymer Shunt Battery Charger System with Low Battery Disconnect 550nA IQ, 1% Float Voltage Accuracy, <10nA Low Battery Disconnect, 4.0V/4.1V/4.2V, 8-Lead 2mm × 3mm DFN and MSOP Packages LTC3129/LTC3129-1 Micropower 200mA Synchronous Buck-Boost DC/DC Converter VIN: 2.42V to 15V, VOUT: 1.4V to 15V, IQ = 1.3μA, ISD = 10nA, MSOP-16E, 3mm × 3mm QFN-16 Packages LTC3330/LTC3331 Nanopower Buck-Boost DC/DC with Energy Harvesting Battery Life Extender VIN: 2.7V to 20V, VOUT: 1.2V to 5.0V, Enable and Standby Pins, IQ = 750nA, 5mm × 5mm QFN-32 Package LTC3388-1/LTC3388-3 20V High Efficiency Nanopower Step-Down Regulator VIN: 2.7V to 20V, VOUT: 1.2V to 5.0V, Enable and Standby Pins, IQ = 720nA, ISD = 400nA, 3mm × 3mm DFN-10, MSOP-10 LTC3588-1 Nanopower Energy Harvesting Power Supply 950nA IQ in Sleep, VOUT: 1.8V, 2.5V, 3.3V, 3.6V, Integrated Bridge Rectifier, MSE-10 and 3mm × 3mm QFN-10 Packages LTC3588-2 Nanopower Energy Harvesting Power Supply <1μA IQ in Regulation, UVLO Rising = 16V, UVLO Falling = 14V, VOUT = 3.45V, 4.1V, 4.5V 5.0, MSE-10 and 3mm × 3mm QFN-10 Packages LTC5800-IPMA IP Wireless Mote-On-Chip Ultralow Power Mote, 72-Lead, 10mm × 10mm QFN 3106f 38 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 For more information www.linear.com/LTC3106 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com/LTC3106 LT 1115 • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 2015