15V, 2.5A Synchronous Buck-Boost DC/DC …

1 LTC311213112fdFor more information APPLICATIONDESCRIPTION15V, SynchronousBuck- boost DC/DC ConverterThe LT C 3112 is a fixed frequency Synchronous Buck-Boost DC/DC converter with an extended input and output range. The unique 4-switch, single inductor architecture provides low noise and seamless operation from input voltages above, below or equal to the output voltage. With an input range of to 15V, the LTC3112 is well-suited for a wide variety of single or multiple cell battery, backup capacitor or wall adapter source applications. Low RDS(ON) internal N-Channel MOSFET switches provide highly efficient operation in applications with higher load current LTC3112 features selectable PWM or Burst Mode operation, an easily synchronized oscillator and output disconnect in shutdown. An output current monitor circuit allows the load current to be controlled or measured. Other features include <1 A shutdown current, short circuit protection, soft-start, current limit and thermal LTC3112 is offered in both a 16-pin (4mm 5mm ) DFN and 20-pin TSSOP at 5 VOUTFEATURESAPPLICATIONSn Regulated Output with VIN Above, Below or Equal to VOUTn to 15V Input Voltage Rangen to 14V Output Voltage Rangen Continuous Output Current.

2 VIN 5V, VOUT = 5V, PWM Moden Output Current Monitorn Up to 95% Efficiencyn 750kHz Switching Frequency, Synchronizable Between 300kHz and Internal N-Channel MOSFETs n Selectable Burst Mode Operation, IQ = 50 An Shutdown Current < 1 An Overvoltage Protectionn Output Disconnect in Shutdownn Internal Soft-Startn Small, Thermally Enhanced 16-Lead (4mm 5mm ) DFN and 20-Lead TSSOP Packagen or 5V from 1, 2 or 3 Li-Ion, Backup Capacitor Stackn Hand Held Inventory Terminalsn RF Transmittersn 12V Synchronous boost Convertern Multiple Power Input Systemsn LED Lighting with Current Regulationn 12V Lead Acid Battery to 12VL, LT, LT C, LT M, Linear Technology Burst Mode, LTSpice and the Linear logo are registered trademarks and No RSENSE and PowerPath are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by Patents, including F680pF22pF33k845k158k47pF47 F1 F10 ADC1V PER AMP5 , VIN > TO 15 VSW1 BST1 VINVCCRUNGNDPWM/SYNCSW2 BST2 VOUTCOMPIOUTOVPFBLTC3112 VOUT3112 TA01 LOAD CURRENT (A) (%) , 750kHz Wide Input Voltage Range Buck-Boost RegulatorLTC311223112fdFor more information CONFIGURATIONABSOLUTE MAXIMUM RATINGSVIN Voltage.

3 To 16 VVOUT Voltage .. to 15 VSW1 Voltage (Note 4) .. to (VIN + )SW2 Voltage (Note 4) .. to (VOUT + )VBST1 Voltage ..(VSW1 ) to (VSW1 + 6V)VBST2 Voltage ..(VSW2 ) to (VSW2 + 6V)(Notes 1, 3)16151413121110917 GND12345678 PWM/SYNCVCCBST1SW1SW1 BST2SW2SW2 COMPFBOVPVINVINRUNIOUTVOUTTOP VIEWDHD16 PACKAGE16-LEAD (5mm 4mm) PLASTIC DFNTJMAX=150 C, qJA = 43 C/W, qJC = 4 C/W EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCBFE PACKAGE20-LEAD PLASTIC TSSOP12345678910 TOP VIEW20191817161514131211 GNDCOMPFBOVPVINVINRUNIOUTVOUTGNDGNDPWM/S YNCVCCBST1SW1SW1 BST2SW2SW2 GND21 GND TJMAX = 150 C, qJA = 38 C/W, qJC = 4 C/W EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCBORDER INFORMATIONLEAD FREE FINISHTAPE AND REELPART MARKING*PACKAGE DESCRIPTIONTEMPERATURE RANGELTC3112 EDHD#PBFLTC3112 EDHD#TRPBF311216-Lead (5mm 4mm) Plastic DFN 40 C to 125 CLTC3112 IDHD#PBFLTC3112 IDHD#TRPBF311216-Lead (5mm 4mm) Plastic DFN 40 C to 125 CLTC3112 HDHD#PBFLTC3112 HDHD#TRPBF311216-Lead (5mm 4mm) Plastic DFN 40 C to 150 CLTC3112 MPDHD#PBFLTC3112 MPDHD#TRPBF311216-Lead (5mm 4mm)

4 Plastic DFN 55 C to 150 CLTC3112 EFE#PBFLTC3112 EFE#TRPBF3112FE20-Lead Plastic TSSOP 40 C to 125 CLTC3112 IFE#PBFLTC3112 IFE#TRPBF3112FE20-Lead Plastic TSSOP 40 C to 125 CLTC3112 HFE#PBFLTC3112 HFE#TRPBF3112FE20-Lead Plastic TSSOP 40 C to 150 CLTC3112 MPFE#PBFLTC3112 MPFE#TRPBF3112FE20-Lead Plastic TSSOP 55 C to 150 CConsult LT C Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LT C Marketing for information on non-standard lead based finish more information on lead free part marking, go to: For more information on tape and reel specifications, go to: Some packages are available in 500 unit reels through designated sales channels with #TRMPBF to 16 VPWM/SYNC, VCC, IOUT Voltage .. to 6 VFB, COMP, OVP Voltage .. to 6 VOperating Junction Temper atur e Range (Notes 2, 6).. 55 C to 150 CStorage Temper atur e Range.

5 65 C to 150 CLead Temper atur e (Soldering, 10sec) TSSOP ..300 #orderinfoLTC311233112fdFor more information The l denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25 C (Note 2). VIN = VOUT = PWM/SYNC = RUN = 5V unless otherwise CHARACTERISTICSPARAMETERCONDITIONSMINTYP MAXUNITSI nput Operating Range0 C to 150 C 55 C to 0 15V VVIN UVLO UVLO Hysteresis300mVVCC UVLO UVLO Hysteresis150mVOutput Voltage Adjust Clamp VoltageVIN = 5V or Voltage in DropoutVIN = , IVCC = Current Burst Mode OperationVFB = 1V, VPWM/SYNC = 0V5075 AQuiescent Current ShutdownRUN = VOUT = VCC = 0V, Not Including Switch Leakage01 AFeedback Voltage = PWM Mode LeakageVFB = ThresholdRising HysteresisMeasured at OVP Pin20mVOVP LeakageOVP = Switch LeakageSwitch A, B, C, D, VIN = VOUT = 12V110 ANMOS Switch On ResistanceSwitch A40m NMOS Switch On ResistanceSwitch B, C50m NMOS Switch On ResistanceSwitch D60m Input Current LimitL = Current LimitL = H71012 ABurst Current LimitL = Zero Current ThresholdL = Current LimitL = H 1 Accuracy (Note 5)

6 SW2 to VOUT Current = SW2 to VOUT Current = SW2 to VOUT Current = 20 836 24 1240 28 16 A A AMaximum Duty CycleBuck (Switch A On)l8087% boost (Switch C On)l7582%Minimum Duty CycleBuck (Switch A On)l0% boost (Switch C On)l512%FrequencyPWM/SYNC = 5V, VIN = VOUT = 12Vl675750825kHzSYNC Frequency Range (Note 7)l3001500kHzPWM/SYNC ThresholdVCC = or ThresholdVIN = or 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 2: The LTC3112 is tested under pulsed load conditions such that TJ TA. The LTC3112E 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 LTC3112I is guaranteed to meet specifications over the 40 C to 125 C operating junction temperature, the LTC3112H is guaranteed to meet specifications over the 40 C to 150 C operating junction temperature range and the LTC3112MP is guaranteed and tested to meet specifications over the full 55 C to 150 C operating junction temperature range.

7 High junction temperatures degrade operating lifetimes; operating lifetime is derated for temperature greater than 125 C. Note that the maximum ambient temperature consistent with these specifications is determined by specific operating conditions in conjunction with board layout, the rated package thermal impedance and other environmental more information PERFORMANCE CHARACTERISTICSWide VIN to Power LossWide VIN to 12 VOUT EfficiencyWide VIN to 12 VOUT Power LossWide VIN to 5 VOUT EfficiencyWide VIN to 5 VOUT Power LossWide VIN to EfficiencyTA = 25 C, VIN = , VOUT = unless otherwise specifiedELECTRICAL CHARACTERISTICSLOAD CURRENT (A) (%) CURRENT (A) LOSS (W) LOSS12 VIN LOSSPWMBURSTLOAD CURRENT (A) (%) CURRENT (A) LOSS (W) LOSS12 VIN LOSSPWMBURSTLOAD CURRENT (A) (%) CURRENT (A) LOSS (W) LOSS12 VIN LOSSPWMBURSTNote 3: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions.

8 Junction temperature will exceed 150 C when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may impair device reliability. Note 4: Voltage transients on the switch pins beyond the DC limit specified in the Absolute Maximum Ratings, are non disruptive to normal operation when using good layout practices, as shown on the demo board or described in the data sheet and application 5: IOUT current is tested in a non-switching DC state. In a switching environment IOUT accuracy may exhibit variation with factors such as switching frequency, load current, input/output voltage, and temperature. See typical performance characteristic curves for predicted 6: The junction temperature (TJ, in C) is calculated from the ambient temperature (TA, in C) and power dissipation (PD, in Watts) according to the formula: TJ = TA + (PD qJA), where qJA (in C/W) is the package thermal 7: SYNC frequency range is tested with a square wave.

9 Operation with 100ns minimum high or low times is assured by more information Output CurrentPWM ModeMaximum Output CurrentBurst Mode Operation12 VIN to 12 VOUT Efficiency vs Frequency with HVIN (V)2 MAXIMUM OUTPUT CURRENT (A) 7 8 9 10 11 12 13 14 1553112 (V)2 MAXIMUM OUTPUT CURRENT (mA)32040048056016024008046 7 8 9 10 11 12 13 14 1553112 CURRENT (mA) (%) G06500kHz750 KHz1000kHz1500kHzTYPICAL PERFORMANCE CHARACTERISTICSTA = 25 C, VIN = , VOUT = unless otherwise specifiedVCC Voltage vs VCC CurrentBoost Mode Minimum SW1 Low Time vs VCC Voltage Normalized N-Channel MOSFET Resistance vs VCC 750kHz PWM Mode No-Load Input CurrentBurst Mode No-Load Input Current with VCC from VIN or Back-Fed from VOUT with Optional DiodeVCC Voltage vs VIN PWM Mode No LoadVIN (V)2 VIN CURRENT (mA)202510150546 7 8 9 10 11 12 13 14 1553112 G073 VOUT = 5 VVIN (V)3 CURRENT FROM VIN ( A)2503003501502000501005791113153112 G08 VOUT = 5 VVCC FROM VINVCC FROM VOUTVIN (V)2 VCC (V) 7 8 910 11 12 13 14 1553112 G093 CURRENT FROM VCC (mA)0 VCC (V) G10 VIN = 5 VVCC VOLTAGE (V) SW1 LOW TIME (ns) G11 VCC (V) N-CHANNEL MOSFET G12 LTC311263112fdFor more information PERFORMANCE CHARACTERISTICSTA = 25 C, VIN = , VOUT = unless otherwise specifiedIOUT Pin Current vs Load CurrentIOUT Voltage vs VOUT CurrentRUN and PWM/SYNC Threshold Voltage vs TemperaturePWM Mode ILIMIT, IPEAK, IREV vs TemperatureBurst Mode OperationIPEAK, IZERO vs TemperatureIOUT Voltage vs VIN Normalized N-Channel MOSFET Resistance vs TemperatureFeedback Pin Program Voltage vs TemperatureVCC and VIN UVLO vs TemperatureTEMPERATURE ( C) 60 NORMALIZED N-CHANNEL MOSFET 40 60 80 100 120 140 160 40 20 03112 G13 TEMPERATURE ( C)FEEDBACK PROGRAMMED VOLTAGE (V)

10 G14 6020 40 60 80 100 120 140 160 40 20 0 TEMPERATURE ( C)UNDERVOLTAGE LOCKOUT (V) G15 VIN FALLINGVIN RISINGVCC FALLINGVCC RISING 6020 40 60 80 100 120 140 160 40 20 0 TEMPERATURE ( C)THRESHOLD VOLTAGE (V) G16 RUN FALLINGRUN RISINGPWM/SYNC FALLINGPWM/SYNC RISING 6020 40 60 80 100 120 140 160 40 20 0 TEMPERATURE ( C)L = HCURRENT (A)81012246 203112 G17 IPEAKILIMITIREV 6020 40 60 80 100 120 140 160 40 20 0 TEMPERATURE ( C)CURRENT (A) G18 IZEROIPEAKL = H 6020 40 60 80 100 120 140 160 40 20 0 TEMPERATURE ( C)IOUT PIN CURRENT ( A)3839403435363732333112 G19 6020 40 60 80 100 120 140 160 40 20 0 VOUT CURRENT (A)0 IOUT VOLTAGE (mV) G20 VIN = 12 VVIN = 8 VVIN = 5 VVIN = 3 VRIOUT = , CIOUT = 100pF, VOUT = 5V, 750kHzVIN (V)2 3 IOUT VOLTAGE (mV)150020002500500100008 9710 11 12 13 14 154 5 63112 G21 IOUT = 2 AIOUT = = 1 AIOUT = 500mARIOUT = , CIOUT = 100pF, VOUT = 5V, 750kHzLTC311273112fdFor more information PERFORMANCE CHARACTERISTICSTA = 25 C, VIN = , VOUT = unless otherwise specifiedIOUT Voltage vs VOUTIOUT Voltage vs VIN and Switching Die Temperature Rise vs Continuous Load Current 4 Layer Demo Board at 25 CVOUT (V)23 IOUT VOLTAGE (mV)1500200025005001000089710 11 12 13 144563112 G22 IOUT = 2 AIOUT = = 1 AIOUT = 500mARIOUT = , CIOUT = 100pF, VIN = , 750kHzVIN (V)2 3 IOUT VOLTAGE (mV)150020002500500100008 9710 11 12 13 14 154 5 63112 G232A, 1500kHz2A, 750kHz2A, 300kHz1A, 1500kHz1A, 750kHz1A, 300kHzRIOUT = , CIOUT = 100pF, VOUT = 5V, 750kHzLOAD CURRENT (A)0 TEMPERATURE RISE ( C)