TPS61220 TPS61221 TPS61222 www.ti.com ............................................................................................................................................................................................... SLVS776 - JANUARY 2009 LOW INPUT VOLTAGE STEP-UP CONVERTER IN 6 PIN SC-70 PACKAGE * * * FEATURES 1 * * * * * * * Up to 95% Efficiency at Typical Operating Conditions 5.5 A Quiescent Current Startup Into Load at 0.7 V Input Voltage Operating Input Voltage from 0.7 V to 5.5 V Pass-Through Function during Shutdown Minimum Switching Current 200 mA Protections: - Output Overvoltage - Overtemperature - Input Undervoltage Lockout Adjustable Output Voltage from 1.8 V to 5.5 V Fixed Output Voltage Versions Small 6-pin SC-70 Package APPLICATIONS * Battery Powered Applications - 1 to 3 Cell Alkaline, NiCd or NiMH - 1 cell Li-Ion or Li-Primary Solar or Fuel Cell Powered Applications Consumer and Portable Medical Products Personal Care Products White or Status LEDs Smartphones * * * * * DESCRIPTION The TPS6122x family devices provide a power-supply solution for products powered by either a single-cell, two-cell, or three-cell alkaline, NiCd or NiMH, or one-cell Li-Ion or Li-polymer battery. Possible output currents depend on the input-to-output voltage ratio. The boost converter is based on a hysteretic controller topology using synchronous rectification to obtain maximum efficiency at minimal quiescent currents. The output voltage of the adjustable version can be programmed by an external resistor divider, or is set internally to a fixed output voltage. The converter can be switched off by a featured enable pin. While being switched off, battery drain is minimized. The device is offered in a 6-pin SC-70 package (DCK) measuring 2 mm x 2 mm to enable small circuit layout size. L1 R1 VIN 0.7 V to VOUT VOUT L 4.7 H VIN C1 10 F FB VOUT C2 1.8 V to 5.5 V 10 F R2 EN GND TPS61220 Efficiency vs Output Current and Input Voltage (VOUT = 3.3V) 1.3 80% 1.8 2.3 90% 2.8 0.01 0.1 1 I OUT - Output Current - mA 10 VIN - Input Voltage - V 0.8 70% 100 1 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright (c) 2009, Texas Instruments Incorporated TPS61220 TPS61221 TPS61222 SLVS776 - JANUARY 2009 ............................................................................................................................................................................................... www.ti.com These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. AVAILABLE DEVICE OPTIONS (1) TA OUTPUT VOLTAGE DC/DC PACKAGE MARKING Adjustable CKR 3.3 V CKS 5.0 V CKT -40C to 85C (1) (2) (3) PACKAGE (2) PART NUMBER (3) TPS61220DCK 6-Pin SC-70 TPS61221DCK TPS61222DCK Contact the factory to check availability of other fixed output voltage versions. For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI website at www.ti.com. The DCK package is available taped and reeled. Add R suffix to device type (e.g., TPS61220DCKR) to order quantities of 3000 devices per reel. It is also available in minireels. Add a T suffix to the device type (i.e. TPS61220DCKT) to order quantities of 250 devices per reel. ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) (1) TPS6122x UNIT VIN Input voltage range on VIN, L, VOUT, EN, FB - 0.3 to 7.5 V TJ Operating junction temperature range -40 to 150 C Tstg Storage temperature range -65 to 150 C 2 kV Human Body Model (HBM) ESD Machine Model (MM) (2) (2) Charged Device Model (CDM) (2) (1) (2) 200 V 1.5 kV Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. ESD testing is performed according to the respective JESD22 JEDEC standard. DISSIPATION RATINGS TABLE PACKAGE THERMAL RESISTANCE JA (1) THERMAL RESISTANCE JB THERMAL RESISTANCE JC POWER RATING TA 25C DERATING FACTOR ABOVE TA = 25C DCK 225 C/W 70 C/W 110 C/W 444 mW 4.44 mW/C (1) Thermal ratings are determined assuming a high K PCB design according to JEDEC standard JESD51-7. RECOMMENDED OPERATING CONDITIONS MIN NOM MAX UNIT VIN Supply voltage at VIN 0.7 5.5 V TA Operating free air temperature range -40 85 C TJ Operating virtual junction temperature range -40 125 C 2 Submit Documentation Feedback Copyright (c) 2009, Texas Instruments Incorporated Product Folder Link(s): TPS61220 TPS61221 TPS61222 TPS61220 TPS61221 TPS61222 www.ti.com ............................................................................................................................................................................................... SLVS776 - JANUARY 2009 ELECTRICAL CHARACTERISTICS over recommended free-air temperature range and over recommended input voltage range (typical at an ambient temperature range of 25C) (unless otherwise noted) DC/DC STAGE PARAMETER TEST CONDITIONS VIN Input voltage range VIN Minimum input voltage at startup RLoad 150 VOUT TPS61220 output voltage range VIN < VOUT VFB TPS61220 feedback voltage VOUT TPS61221 output voltage (3.3V) VOUT TPS61222 output voltage (5V) ILH Inductor current ripple ISW switch current limit RDSon_HSD RDSon_LSD MIN TYP 0.7 Rectifying switch on resistance Main switch on resistance 1.8 V 5.5 V 513 mV VIN < VOUT 3.20 3.30 3.41 V VIN < VOUT 4.82 5.00 5.13 VOUT = 3.3 V, VIN = 1.2 V, TA = 25 C 240 VOUT = 3.3 V 200 V 200 mA 400 mA 400 mA VOUT = 3.3 V 1000 m VOUT = 5.0 V 700 m VOUT = 3.3 V 600 m 550 m VIN < VOUT 0.5 % Load regulation VIN < VOUT 0.5 % IQ Quiescent current ISD Shutdown current ILKG_VOUT Leakage current into VOUT VEN = 0 V, VIN = 1.2 V, VOUT = 3.3 V ILKG_L Leakage current into L VEN = 0 V, VIN = 1.2 V, VL = 1.2 V, VOUT VIN IFB TPS61220 Feedback input current VFB = 0.5 V IEN EN input current Clamped on GND or VIN (VIN < 1.5 V) IO = 0 mA, VEN = VIN = 1.2 V, VOUT = 3.3 V VEN = 0 V, VIN = 1.2 V, VOUT VIN VIN V 0.7 500 VOUT = 5.0 V VOUT UNIT 5.5 483 Line regulation VIN MAX 0.5 0.9 A 5 7.5 A 0.2 0.5 A A 1 0.01 0.005 0.2 A 0.01 A 0.1 A CONTROL STAGE PARAMETER TEST CONDITIONS VIL EN input low voltage VIN 1.5 V VIH EN input high voltage VIN 1.5 V VIL EN input low voltage 5 V > VIN > 1.5 V VIH EN input high voltage 5 V > VIN > 1.5 V VUVLO Undervoltage lockout threshold for turn off VIN decreasing MIN TYP MAX 0.2 x VIN 0.8 x VIN V V 0.4 1.2 V V 0.5 Overvoltage protection threshold UNIT 5.5 0.7 7.5 V V Overtemperature protection 140 C Overtemperature hysteresis 20 C Copyright (c) 2009, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Link(s): TPS61220 TPS61221 TPS61222 3 TPS61220 TPS61221 TPS61222 SLVS776 - JANUARY 2009 ............................................................................................................................................................................................... www.ti.com PIN ASSIGNMENTS DCK PACKAGE (TOP VIEW) VIN FB GND EN L VOUT Terminal Functions TERMINAL NAME NO. I/O DESCRIPTION EN 6 I Enable input (1: enabled, 0: disabled). Must be actively tied high or low. FB 2 I Voltage feedback of adjustable version. Must be connected to VOUT at fixed output voltage versions. GND 3 L 5 I Connection for Inductor VIN 1 I Boost converter input voltage VOUT 4 O Boost converter output voltage Control / logic and power ground FUNCTIONAL BLOCK DIAGRAM (ADJUSTABLE VERSION) L VOUT VOUT VIN Gate Driver VIN Start Up EN Device Control Current Sensor GND 4 FB VREF Submit Documentation Feedback Copyright (c) 2009, Texas Instruments Incorporated Product Folder Link(s): TPS61220 TPS61221 TPS61222 TPS61220 TPS61221 TPS61222 www.ti.com ............................................................................................................................................................................................... SLVS776 - JANUARY 2009 FUNCTIONAL BLOCK DIAGRAM (FIXED OUTPUT VOLTAGE VERSION) L VOUT VOUT VIN Gate Driver VIN Start Up EN Device Control Current Sensor FB GND VREF PARAMETER MEASUREMENT INFORMATION L1 L VOUT VOUT R1 VIN VIN EN C1 C2 FB R2 GND TPS6122x List of Components: COMPONENT REFERENCE PART NUMBER MANUFACTURER VALUE C1 GRM188R60J106ME84D Murata 10 F, 6.3V. X5R Ceramic C2 GRM188R60J106ME84D Murata 10 F, 6.3V. X5R Ceramic L1 EPL3015-472MLB Coilcraft 4.7 H adjustable version: Values depending on the programmed output voltage R1, R2 fixed version: R1= 0 , R2 not used Copyright (c) 2009, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Link(s): TPS61220 TPS61221 TPS61222 5 TPS61220 TPS61221 TPS61222 SLVS776 - JANUARY 2009 ............................................................................................................................................................................................... www.ti.com TYPICAL CHARACTERISTICS Table of Graphs FIGURE Maximum Output Current Efficiency Input Current Output Voltage Waveforms vs Input Voltage (TPS61220, TPS61221, TPS61222) 1 vs Output Current, VOUT = 1.8 V, VIN = [0.7 V; 1.2 V; 1.5 V] (TPS61220) 2 vs Output Current, VIN = [0.7 V; 1.2 V; 2.4 V; 3 V] (TPS61221) 3 vs Output Current, VIN = [0.7 V; 1.2 V; 2.4V; 3.6 V; 4.2 V] (TPS61222) 4 vs Input Voltage, VOUT = 1.8 V, IOUT = [100 uA; 1 mA; 10 mA; 50 mA] (TPS61220) 5 vs Input Voltage, IOUT = [100 uA; 1 mA; 10 mA; 50 mA] (TPS61221) 6 vs Input Voltage, IOUT = [100 uA; 1 mA; 10 mA; 50 mA] (TPS61222) 7 at No Output Load, Device Enabled (TPS61220, TPS61221, TPS61222) 8 vs Output Current, VOUT = 1.8 V, VIN = [0.7 V; 1.2 V] (TPS61220 ) 9 vs Output Current, VIN = [0.7 V; 1.2 V; 2.4 V] (TPS61221) 10 vs Output Current, VIN = [0.7 V; 1.2 V; 2.4 V; 3.6 V] (TPS61222) 11 vs Input Voltage, Device Disabled, RLOAD = [1 k; 10 k] (TPS6122x) 12 Output Voltage Ripple, VIN = 0.8 V, VOUT = 1.8 V, IOUT = 20 mA (TPS61220) 13 Output Voltage Ripple VIN = 1.8 V, IOUT = 50mA (TPS61221) 14 Load Transient Response, VIN = 1.2 V, IOUT = 6 mA to 50 mA (TPS61221) 15 Load Transient Response, VIN = 2.4 V, IOUT = 14 mA to 126 mA (TPS61222) 16 Line Transient Response, VIN = 1.8 V to 2.4 V, RLOAD = 100 (TPS61221) 17 Line Transient Response, VIN = 2.8 V to 3.6 V, RLOAD = 100 (TPS61222) 18 Startup after Enable, VIN = 0.7 V, VOUT = 1.8 V, RLOAD = 150 (TPS61220) 19 Startup after Enable, VIN = 0.7 V, RLOAD = 150 , (TPS61222) 20 Continuous Current Operation, VIN = 1.2 V, VOUT = 1.8 V, IOUT = 50mA (TPS61220 ) 21 Discontinuous Current Operation, VIN = 1.2 V, VOUT = 1.8 V, IOUT = 10mA (TPS61220) 22 MAXIMUM OUTPUT CURRENT vs INPUT VOLTAGE (TPS61220, TPS61221, TPS61222) EFFICIENCY vs OUTPUT CURRENT AND INPUT VOLTAGE (TPS61220) 300 100 90 VO = 1.8 V 80 200 70 TPS61221 VO = 3.3 V h - Efficiency - % Maximum output Current - mA 250 150 TPS61222 VO = 5 V 100 60 VI = 1.2 V 50 40 30 20 50 TPS61220 VO = 1.8 V 10 0 0.7 1.2 1.7 2.2 2.7 3.2 VI - Input Voltage - V 3.7 4.2 4.7 0 0.01 0.1 1 IO - Output Current - mA Figure 1. 6 VI = 1.5 V VI = 0.7 V Submit Documentation Feedback 10 100 Figure 2. Copyright (c) 2009, Texas Instruments Incorporated Product Folder Link(s): TPS61220 TPS61221 TPS61222 TPS61220 TPS61221 TPS61222 www.ti.com ............................................................................................................................................................................................... SLVS776 - JANUARY 2009 EFFICIENCY vs OUTPUT CURRENT AND INPUT VOLTAGE (TPS61221) EFFICIENCY vs OUTPUT CURRENT AND INPUT VOLTAGE (TPS61222) 100 100 VO = 3.3 V VO = 5 V 90 90 80 80 70 VI = 3 V 60 50 h - Efficiency - % h - Efficiency - % 70 VI = 2.4 V VI = 1.2 V VI = 0.7 V 40 60 20 20 10 10 1 IO - Output Current - mA 10 0 0.01 100 0.1 1 IO - Output Current - mA 10 100 Figure 3. Figure 4. EFFICIENCY vs INPUT VOLTAGE AND OUTPUT CURRENT (TPS61220) EFFICIENCY vs INPUT VOLTAGE AND OUTPUT CURRENT (TPS61221) 100 100 VO = 1.8 V 90 90 IO = 10 mA 80 h - Efficiency - % 60 IO = 50 mA 50 40 60 20 20 10 10 1.5 IO = 50 mA 40 30 1.1 1.3 VI - Input Voltage - V IO = 1 mA 50 30 0.9 IO = 100 mA 70 IO = 1 mA IO = 100 mA 0 0.7 IO = 10 mA 80 70 h - Efficiency - % VI = 4.2 V VI = 1.2 V 30 0.1 VI = 3.6 V VI = 0.7 V 40 30 0 0.01 VI = 2.4 V 50 0 0.7 1.7 VO = 3.3 V 1.2 1.7 2.2 VI - Input Voltage - V 2.7 3.2 Figure 5. Figure 6. EFFICIENCY vs INPUT VOLTAGE AND OUTPUT CURRENT (TPS61222) NO LOAD INPUT CURRENT vs INPUT VOLTAGE, DEVICE ENABLED (TPS61220 VOUT=1.8, TPS61221, TPS61222) 80 100 VO = 5 V Device Enabled 70 80 IO = 50 mA 60 II - Input Current - mA h - Efficiency - % IO = 10 mA IO = 1 mA 60 IO = 100 mA 40 TPS61222, VO = 5 V 50 TPS61221, VO = 3.3 V 40 30 TPS61220, VO = 1.8 V 20 20 10 0 0.7 1.7 2.7 VI - Input Voltage - V 3.7 4.7 0 0.7 1.7 2.7 3.7 VI - Input Voltage - V Figure 7. Copyright (c) 2009, Texas Instruments Incorporated 4.7 Figure 8. Submit Documentation Feedback Product Folder Link(s): TPS61220 TPS61221 TPS61222 7 TPS61220 TPS61221 TPS61222 SLVS776 - JANUARY 2009 ............................................................................................................................................................................................... www.ti.com OUTPUT VOLTAGE vs OUTPUT CURRENT AND INPUT VOLTAGE (TPS61220) OUTPUT VOLTAGE vs OUTPUT CURRENT AND INPUT VOLTAGE (TPS61221) 3.5 1.9 VO = 1.8 V VO = 3.3 V 3.4 VO - Output Voltage - V VO - Output Voltage - V 1.85 VI = 1.2 V 1.8 VI = 0.7 V 1.75 1.7 0.01 0.1 1 IO - Output Current - mA 10 VI = 2.4 V 3.3 VI = 0.7 V VI = 1.2 V 3.2 3.1 0.01 100 0.1 1 IO - Output Current - mA 10 100 Figure 9. Figure 10. OUTPUT VOLTAGE vs OUTPUT CURRENT AND INPUT VOLTAGE (TPS61222) OUTPUT VOLTAGE vs INPUT VOLTAGE, DEVICE DISABLED (TPS61220) 4.5 5.2 VEN = 0 V VO = 5 V VO - Output Voltage - V 4 VO - Output Voltage - V 5.1 VI = 3.6 V 5 VI = 2.4 V VI = 1.2 V 4.9 VI = 0.7 V 3.5 3 2.5 RLOAD = 10 kW 2 1.5 RLOAD = 1 kW 1 0.5 4.8 0.01 0.1 1 IO - Output Current - mA 10 100 0 0.7 1.2 1.7 2.2 2.7 3.2 3.7 VI - Input Voltage - V 4.2 4.7 Figure 11. Figure 12. OUTPUT VOLTAGE RIPPLE (TPS61220) OUTPUT VOLTAGE RIPPLE (TPS61221) 5.2 VI = 1.8 V, VO = 3.3 V, IO = 50 mA VI = 0.8 V, VO = 1.8 V, IO = 20 mA Icoil Icoil 50 mA/div 50 mA/div Offset: 0 V Offset: 0 A VO VO 10 mV/div 10 mA/div Offset: 3.31 V Offset: 1.8 V 1 ms/div 1 ms/div Figure 13. 8 Submit Documentation Feedback Figure 14. Copyright (c) 2009, Texas Instruments Incorporated Product Folder Link(s): TPS61220 TPS61221 TPS61222 TPS61220 TPS61221 TPS61222 www.ti.com ............................................................................................................................................................................................... SLVS776 - JANUARY 2009 LOAD TRANSIENT RESPONSE (TPS61221) LOAD TRANSIENT RESPONSE (TPS61222) Offset: 0 A IL Offset: 0 A 200 mA/div IL 200 mA/div IO Offset: 0 A 50 mA/div IO Offset: 0 A 20 mA/div VO Offset: 3.31 V 50 mV/div VO Offset: 5 V 50 mV/div VI = 2.4 V, IO = 14 mA to 126 mA VI =1.2 V, IO = 6 mA to 50 mA 200 ms/div 200 ms/div Figure 15. Figure 16. LINE TRANSIENT RESPONSE (TPS61221) LINE TRANSIENT RESPONSE (TPS61222) VI VI 200 mV/div 200 mV/div Offset: 2.8 V Offset: 1.8 V VO VO 20 mV/div Offset: 3.3 V 20 mV/div VI 1.8 to 2.4 V, RLOAD = 100 W, trise = tfall = 20 ms VI 2.8 to 3.6 V, RLOAD = 100 W, trise = tfall = 20 ms Offset: 5 V 200 ms/div 200 ms/div Figure 17. Figure 18. STARTUP AFTER ENABLE (TPS61120) STARTUP AFTER ENABLE (TPS61221) VI = 0.7 V, VO = 1.8 V, RLOAD = 150 W VEN 500 mV/div VI = 0.7 V, VO = 3.3 V, RLOAD = 50 W Offset: 0 V VEN 500 mV/div Offset: 0 A Icoil Offset: 0 V Offset: 0 A Icoil 100 mA/div 100 mA/div Offset: 0 V VL 1 V/div VL 2 V/div Offset: 0 V VO 2 V/div Offset: 0 V Offset: 0 V VO 1 V/div 500 ms/div 500 ms/div Figure 19. Figure 20. Copyright (c) 2009, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Link(s): TPS61220 TPS61221 TPS61222 9 TPS61220 TPS61221 TPS61222 SLVS776 - JANUARY 2009 ............................................................................................................................................................................................... www.ti.com CONTINUOUS CURRENT OPERATION (TPS61220) DISCONTINUOUS CURRENT OPERATION (TPS61220) VI = 1.2 V, VO = 1.8 V, IO = 50 mA VI = 1.2 V, VO = 1.8 V, IO = 10 mA Icoil Icoil 100 mA/div 100 mA/div Offset: 0 A VL 2 V/div Offset: 0 A VL 2 V/div Offset: 0 V Offset: 0 V VO 10 mV/div VO 10 mV/div Offset: 1.8 V Offset: 1.8 V 1 ms/div 1 ms/div Figure 21. 10 Submit Documentation Feedback Figure 22. Copyright (c) 2009, Texas Instruments Incorporated Product Folder Link(s): TPS61220 TPS61221 TPS61222 TPS61220 TPS61221 TPS61222 www.ti.com ............................................................................................................................................................................................... SLVS776 - JANUARY 2009 DETAILED DESCRIPTION OPERATION The TPS6122x is a high performance, high efficient family of switching boost converters. To achieve high efficiency the power stage is realized as a synchronous boost topology. For the power switching two actively controlled low RDSon power MOSFETs are implemented. CONTROLLER CIRCUIT The device is controlled by a hysteretic current mode controller. This controller regulates the output voltage by keeping the inductor ripple current constant in the range of 200 mA and adjusting the offset of this inductor current depending on the output load. In case the required average input current is lower than the average inductor current defined by this constant ripple the inductor current gets discontinuous to keep the efficiency high at low load conditions. IL Continuous Current Operation Discontinuous Current Operation 200 mA (typ.) 200 mA (typ.) t Figure 23. Hysteretic Current Operation The output voltage VOUT is monitored via the feedback network which is connected to the voltage error amplifier. To regulate the output voltage, the voltage error amplifier compares this feedback voltage to the internal voltage reference and adjusts the required offset of the inductor current accordingly. At fixed output voltage versions an internal feedback network is used to program the output voltage, at adjustable versions an external resistor divider needs to be connected. The self oscillating hysteretic current mode architecture is inherently stable and allows fast response to load variations. It also allows using inductors and capacitors over a wide value range. Device Enable and Shutdown Mode The device is enabled when EN is set high and shut down when EN is low. During shutdown, the converter stops switching and all internal control circuitry is turned off. In this case the input voltage is connected to the output through the back-gate diode of the rectifying MOSFET. This means that there always will be voltage at the output which can be as high as the input voltage or lower depending on the load. Startup After the EN pin is tied high, the device starts to operate. In case the input voltage is not high enough to supply the control circuit properly a startup oscillator starts to operate the switches. During this phase the switching frequency is controlled by the oscillator and the maximum switch current is limited. As soon as the device has built up the output voltage to about 1.8V, high enough for supplying the control circuit, the device switches to its normal hysteretic current mode operation. The startup time depends on input voltage and load current. Operation at Output Overload If in normal boost operation the inductor current reaches the internal switch current limit threshold the main switch is turned off to stop further increase of the input current. In this case the output voltage will decrease since the device can not provide sufficient power to maintain the set output voltage. If the output voltage drops below the input voltage the backgate diode of the rectifying switch gets forward biased and current starts flow through it. This diode cannot be turned off, so the current finally is only limited by the remaining DC resistances. As soon as the overload condition is removed, the converter resumes providing the set output voltage. Copyright (c) 2009, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Link(s): TPS61220 TPS61221 TPS61222 11 TPS61220 TPS61221 TPS61222 SLVS776 - JANUARY 2009 ............................................................................................................................................................................................... www.ti.com Undervoltage Lockout An implemented undervoltage lockout function stops the operation of the converter if the input voltage drops below the typical undervoltage lockout threshold. This function is implemented in order to prevent malfunctioning of the converter. Overvoltage Protection If, for any reason, the output voltage is not fed back properly to the input of the voltage amplifier, control of the output voltage will not work anymore. Therefore an overvoltage protection is implemented to avoid the output voltage exceeding critical values for the device and possibly for the system it is supplying. For this protection the TPS6122x output voltage is also monitored internally. In case it reaches the internally programmed threshold of 6.5 V typically the voltage amplifier regulates the output voltage to this value. If the TPS6122x is used to drive LEDs, this feature protects the circuit if the LED fails. Overtemperature Protection The device has a built-in temperature sensor which monitors the internal IC junction temperature. If the temperature exceeds the programmed threshold (see electrical characteristics table), the device stops operating. As soon as the IC temperature has decreased below the programmed threshold, it starts operating again. To prevent unstable operation close to the region of overtemperature threshold, a built-in hysteresis is implemented. 12 Submit Documentation Feedback Copyright (c) 2009, Texas Instruments Incorporated Product Folder Link(s): TPS61220 TPS61221 TPS61222 TPS61220 TPS61221 TPS61222 www.ti.com ............................................................................................................................................................................................... SLVS776 - JANUARY 2009 APPLICATION INFORMATION DESIGN PROCEDURE The TPS6122x DC/DC converters are intended for systems powered by a single cell battery to up to three Alkaline, NiCd or NiMH cells with a typical terminal voltage between 0.7 V and 5.5 V. They can also be used in systems powered by one-cell Li-Ion or Li-Polymer batteries with a typical voltage between 2.5 V and 4.2 V. Additionally, any other voltage source with a typical output voltage between 0.7 V and 5.5 V can be used with the TPS6122x family. Programming the Output Voltage Fixed output voltage versions At fixed voltage versions, the output voltage is set by a resistor divider internally. The FB pin is used to sense the output voltage. To configure the fixed output devices properly, the FB pin needs to be connected directly to VOUT as shown in Figure 24. L1 L VIN VOUT VOUT VIN C2 FB EN C1 GND TPS6122x fixed output voltage Figure 24. Typical Application Circuit for Fixed Output Voltage Option Adjustable output voltage version In the adjustable output versions, an external resistor divider is used to adjust the output voltage. The resistor divider needs to be connected between VOUT, FB and GND as shown in Figure 25. When the output voltage is regulated properly, the typical voltage value at the FB pin is 500 mV for the adjustable devices. The maximum recommended value for the output voltage is 5.5 V. The current through the resistive divider should be about 100 times greater than the current into the FB pin. The typical current into the FB pin is 0.01 A, and the voltage across the resistor between FB and GND, R2, is typically 500 mV. Based on those two values, the recommended value for R2 should be lower than 500 k, in order to set the divider current to 1 A or higher. The value of the resistor connected between VOUT and FB, R1, depending on the needed output voltage (VOUT), can be calculated using Equation 1: aeV o R1 = R 2 x c OUT - 1/ e VFB o (1) As an example, if an output voltage of 3.3 V is needed, a 1-M resistor is calculated for R1 when for R2 a 180-k has been selected. L1 L VOUT VOUT R1 VIN VIN EN C1 C2 FB R2 GND TPS6122x Figure 25. Typical Application Circuit for Adjustable Output Voltage Option Copyright (c) 2009, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Link(s): TPS61220 TPS61221 TPS61222 13 TPS61220 TPS61221 TPS61222 SLVS776 - JANUARY 2009 ............................................................................................................................................................................................... www.ti.com Inductor Selection To make sure that the TPS6122x devices can operate, a suitable inductor must be connected between pin VIN and pin L. Inductor values of 4.7 H show good performance over the whole input and output voltage range . Choosing other inductance values affects the switching frequency f proportional to 1/L as shown in Equation 2. L= V (VOUT - VIN ) 1 IN f 200 mA VOUT (2) Choosing inductor values higher than 4.7 H can improve efficiency due to reduced switching frequency and therefore with reduced switching losses. Using inductor values below 2.2 H is not recommended. Having selected an inductance value, the peak current for the inductor in steady state operation can be calculated. Equation 3 gives the peak current estimate. IL,MAX i VOUT IOUT + 100 mA; continous current operation i = i 0.8 VIN i200 mA; discontinuous current operation i (3) For selecting the inductor this would be the suitable value for the current rating. It also needs to be taken into account that load transients and error conditions may cause higher inductor currents. Equation 4 provides an easy way to estimate whether the device will work in continuous or discontinuous operation depending on the operating points. As long as the inequation is true, continuous operation is typically established. If the inequation becomes false, discontinous operation is typically established. VOUT IOUT > 0.8 100 mA VIN (4) The following inductor series from different suppliers have been used with TPS6122x converters: Table 1. List of Inductors VENDOR Coilcraft INDUCTOR SERIES EPL3015 EPL2010 Murata LQH3NP Tajo Yuden NR3015 Wurth Elektronik WE-TPC Typ S Capacitor Selection Input Capacitor At least a 10-F input capacitor is recommended to improve transient behavior of the regulator and EMI behavior of the total power supply circuit. A ceramic capacitor placed as close as possible to the VIN and GND pins of the IC is recommended. Output Capacitor For the output capacitor C2, it is recommended to use small ceramic capacitors placed as close as possible to the VOUT and GND pins of the IC. If, for any reason, the application requires the use of large capacitors which can not be placed close to the IC, the use of a small ceramic capacitor with an capacitance value of around 2.2F in parallel to the large one is recommended. This small capacitor should be placed as close as possible to the VOUT and GND pins of the IC. 14 Submit Documentation Feedback Copyright (c) 2009, Texas Instruments Incorporated Product Folder Link(s): TPS61220 TPS61221 TPS61222 TPS61220 TPS61221 TPS61222 www.ti.com ............................................................................................................................................................................................... SLVS776 - JANUARY 2009 A minimum capacitance value of 4.7 F should be used, 10 F are recommended. If the inductor value exceeds 4.7 H, the value of the output capacitance value needs to be half the inductance value or higher for stability reasons, see Equation 5. C2 L 2 (5) The TPS6122x is not sensitive to the ESR in terms of stability. Using low ESR capacitors, such as ceramic capacitors, is recommended anyway to minimize output voltage ripple. If heavy load changes are expected, the output capacitor value should be increased to avoid output voltage drops during fast load transients. Layout Considerations As for all switching power supplies, the layout is an important step in the design, especially at high peak currents and high switching frequencies. If the layout is not carefully done, the regulator could show stability problems as well as EMI problems. Therefore, use wide and short traces for the main current path and for the power ground paths. The input and output capacitor, as well as the inductor should be placed as close as possible to the IC. The feedback divider should be placed as close as possible to the control ground pin of the IC. To lay out the ground, it is recommended to use short traces as well, separated from the power ground traces. This avoids ground shift problems, which can occur due to superimposition of power ground current and control ground current. Assure that the ground traces are connected close to the device GND pin. L1 VOUT Enable VIN C2 C1 VOUT VIN GND GND R1 R2 Figure 26. PCB Layout Suggestion for Adjustable Output Voltage Options Copyright (c) 2009, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Link(s): TPS61220 TPS61221 TPS61222 15 TPS61220 TPS61221 TPS61222 SLVS776 - JANUARY 2009 ............................................................................................................................................................................................... www.ti.com THERMAL INFORMATION Implementation of integrated circuits in low-profile and fine-pitch surface-mount packages typically requires special attention to power dissipation. Many system-dependent issues such as thermal coupling, airflow, added heat sinks and convection surfaces, and the presence of other heat-generating components affect the power-dissipation limits of a given component. Three basic approaches for enhancing thermal performance are listed below. * Improving the power-dissipation capability of the PCB design * Improving the thermal coupling of the component to the PCB * Introducing airflow in the system For more details on how to use the thermal parameters in the dissipation ratings table please check the Thermal Characteristics Application Note (SZZA017) and the IC Package Thermal Metrics Application Note (SPRA953). 16 Submit Documentation Feedback Copyright (c) 2009, Texas Instruments Incorporated Product Folder Link(s): TPS61220 TPS61221 TPS61222 PACKAGE OPTION ADDENDUM www.ti.com 23-Apr-2009 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty TPS61220DCKR ACTIVE SC70 DCK 6 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM TPS61220DCKT ACTIVE SC70 DCK 6 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM TPS61221DCKR ACTIVE SC70 DCK 6 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM TPS61221DCKT ACTIVE SC70 DCK 6 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM TPS61222DCKR ACTIVE SC70 DCK 6 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM TPS61222DCKT ACTIVE SC70 DCK 6 250 CU NIPDAU Level-1-260C-UNLIM Green (RoHS & no Sb/Br) Lead/Ball Finish MSL Peak Temp (3) (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. 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Addendum-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 14-Sep-2011 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing TPS61220DCKR SC70 DCK 6 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 3000 179.0 8.4 2.2 2.5 1.2 4.0 8.0 Q3 TPS61220DCKT SC70 DCK 6 250 179.0 8.4 2.2 2.5 1.2 4.0 8.0 Q3 TPS61221DCKR SC70 DCK 6 3000 179.0 8.4 2.2 2.5 1.2 4.0 8.0 Q3 TPS61221DCKT SC70 DCK 6 250 179.0 8.4 2.2 2.5 1.2 4.0 8.0 Q3 TPS61222DCKR SC70 DCK 6 3000 179.0 8.4 2.2 2.5 1.2 4.0 8.0 Q3 TPS61222DCKT SC70 DCK 6 250 179.0 8.4 2.2 2.5 1.2 4.0 8.0 Q3 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 14-Sep-2011 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) TPS61220DCKR SC70 DCK 6 3000 203.0 203.0 35.0 TPS61220DCKT SC70 DCK 6 250 203.0 203.0 35.0 TPS61221DCKR SC70 DCK 6 3000 203.0 203.0 35.0 TPS61221DCKT SC70 DCK 6 250 203.0 203.0 35.0 TPS61222DCKR SC70 DCK 6 3000 203.0 203.0 35.0 TPS61222DCKT SC70 DCK 6 250 203.0 203.0 35.0 Pack Materials-Page 2 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. 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