Product Folder Sample & Buy Support & Community Tools & Software Technical Documents TPS61291 SLVSBX9A – SEPTEMBER 2014 – REVISED SEPTEMBER 2014 TPS61291 Low Iq Boost Converter with Bypass Operation 1 Features • • • • • • • • 1 • • • • • In bypass mode the integrated feedback divider network for boost mode operation is disconnected from the output and the quiescent current consumption drops down to only 15nA (typical). Input Voltage Range 0.9V to 5V Startup Voltage 1.5V at 20mA Load Pin Selectable Output Voltages: 3.3V, 3V, 2.5V 15nA typical Quiescent Current in Bypass Mode 5.7μA typical Quiescent Current in Boost Mode Bypass Switch from VIN to VOUT IOUT > 200mA at 3.3V VOUT, VIN = 1.8V Internal Feedback Divider Disconnect (Bypass Mode) Controlled Bypass Transition Prevents Reverse Current into Battery Power-Save Mode at Light Loads Overtemperature Protection Redundant Overvoltage Protection Small 2mm x 2mm SON 6-pin package In boost mode the device provides a minimum output current of 200mA at 3.3V VOUT from 1.8V VIN. The boost mode is used for system components which require a regulated supply voltage and cannot directly operate from the input source. The boost converter is based on a current-mode controller using synchronous rectification to obtain maximum efficiency and consumes typically 5.7uA from the output. During startup of the boost converter, the VSEL pin is read out and the integrated feedback network sets the output voltage to 2.5V, 3V or 3.3V. Bypass mode or boost mode operation is controlled by the system via the EN/BYP pin. The device integrates an enhanced bypass mode control to prevent charge, stored in the output capacitor during boost mode operation, from flowing back to the input and charging the battery. 2 Applications • • • • Metering (Gas, Water, Smart Meters) Remote Controls Home Security / Home Automation Single 3V Li-MnO2 or 2 x 1.5V Alkaline Cell Powered Applications The device is packaged in a small 6-pin SON package (DRV) measuring 2.0mm × 2.0mm x 0.75mm. Device Information(1) PART NUMBER PACKAGE BODY SIZE (NOM) 3 Description TPS61291 SON (6) 2.00 mm x 2.00 mm The TPS61291 is a boost converter with pin selectable output voltages and an integrated bypass mode. In bypass operation, the device provides a direct path from the input to the system and allows a low power micro controller (MCU) such as the MSP430 to operate directly from a single 3V Li-MnO2 battery or dual alkaline battery cells. (1) For all available packages, see the orderable addendum at the end of the datasheet. Simplified Schematic and Efficiency Curves 100 TPS61291 2 x 1.5V Alkaline / 1 x 3V Li-MnO2 + + - + - VBAT CIN 10mF SW VOUT = Step up converter VOUT VBAT / 3.3V VIN COUT 22mF Bypass VSEL GND 95 Subsystem 90 VCC = 3.3V MCU (VCC = VBAT or 3.3V) 85 Efficiency [%] L = 3.3mH 80 75 VIN = 1.2V 70 VIN = 1.8V EN/BYP 65 VIN = 2.5V 60 VIN = 3.0V 55 50 0.01 0.1 1 10 100 Output Current IOUT [mA] 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. TPS61291 SLVSBX9A – SEPTEMBER 2014 – REVISED SEPTEMBER 2014 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 4 6.1 6.2 6.3 6.4 6.5 6.6 4 4 4 4 5 6 Absolute Maximum Ratings ...................................... Handling Ratings....................................................... Recommended Operating Conditions....................... Thermal Information ................................................. Electrical Characteristics........................................... Typical Characteristics .............................................. Detailed Description .............................................. 7 7.1 Overview ................................................................... 7 7.2 Functional Block Diagram ......................................... 7 7.3 Feature Description................................................... 7 7.4 Device Functional Modes.......................................... 8 8 Applications and Implementation ...................... 10 8.1 Application Information............................................ 10 8.2 Typical Application .................................................. 10 9 Power Supply Recommendations...................... 16 10 Layout................................................................... 16 10.1 Layout Guidelines ................................................. 16 10.2 Layout Example .................................................... 16 11 Device and Documentation Support ................. 17 11.1 11.2 11.3 11.4 11.5 Device Support .................................................... Documentation Support ........................................ Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 17 17 17 17 17 12 Mechanical, Packaging, and Orderable Information ........................................................... 17 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Original (September 2014) to Revision A Page • Changed "Bypass Mode Operation" description ................................................................................................................... 9 • Added sub-section "Controlled Transition into Bypass Mode" .............................................................................................. 9 • Added NOTE to the "Application and Implementation" section. .......................................................................................... 10 • Changed "List of Inductors" table ........................................................................................................................................ 11 2 Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated Product Folder Links: TPS61291 TPS61291 www.ti.com SLVSBX9A – SEPTEMBER 2014 – REVISED SEPTEMBER 2014 5 Pin Configuration and Functions SW VOUT VIN 1 2 3 TH E ER XP M OS A ED L PA D DRV Package 6 Pin Top View 6 5 4 GND VSEL EN/BYP Pin Functions PIN NAME NO. I/O DESCRIPTION SW 1 I Switch node of the converter. Connect the inductor between this pin and the input capacitor CIN. VOUT 2 O Boost converter output. Connect the output capacitor COUT between this pin and GND close to the device. VIN 3 PWR EN/BYP 4 I Control pin of the device. A high level enables the boost mode operation. A low level disables the boost converter and enables bypass mode operation. EN/BYP must be actively terminated high or low. Usually, this pin is controlled by the MCU in the system. VSEL 5 I Output voltage selection pin. The logic level of this pin is read out during startup and internally latched. Connect this pin only to GND, VOUT, or leave it floating. GND 6 PWR EXPOSED THERMAL PAD Input voltage supply pin for the boost converter. Connect the input capacitor CIN between this pin and GND as close as possible to the device. Ground pin of the device. Not electrically connected to the IC, but must be soldered to achieve specified thermal performance. Connect this pad to the GND pin and use it as a central GND plane. NC Output Voltage Setting EN/BYP Pin VSEL Pin at Startup VOUT Mode high GND 3.3V Boost Mode Operation high VOUT 3.0V high floating 2.5V low GND / VOUT / floating VOUT = VIN (Bypass Mode) Bypass Mode Operation Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated Product Folder Links: TPS61291 3 TPS61291 SLVSBX9A – SEPTEMBER 2014 – REVISED SEPTEMBER 2014 www.ti.com 6 Specifications 6.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted) Pin Voltage Range (1) (2) (2) (1) MIN MAX VIN -0.3 5.5 UNIT SW -0.3 7 EN/BYP, VOUT -0.3 5.5 VSEL -0.3 VOUT + 0.3V Output Current In Bypass Operation (EN/BYP = GND) TJ Maximum Junction Temperature -40 V 250 mA 150 °C Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. All voltage values are with respect to network ground terminal GND. 6.2 Handling Ratings Tstg Storage temperature range V(ESD) (1) (2) Electrostatic discharge MIN MAX –65 150 -2 2 -0.5 0.5 Human body model (HBM) per ANSI/ESDA/JEDEC JS-001, all pins (1) Charged device model (CDM), per JEDEC specification JESD22-C101, all pins (2) UNIT °C kV JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. 6.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) MIN VIN NOM MAX Supply voltage for startup 1.5 Supply voltage range (once device has started) 0.9 5 VOUT Supply voltage range for step up conversion (once device has started) 0.9 TA Operating ambient temperature -40 85 TJ Operating junction temperature –40 125 UNIT V °C 6.4 Thermal Information TPS61291 THERMAL METRIC (1) DRV (2x2 SON) UNIT 6 PINS RθJA Junction-to-ambient thermal resistance 71.2 RθJCtop Junction-to-case (top) thermal resistance 93.5 RθJB Junction-to-board thermal resistance 46.7 ψJT Junction-to-top characterization parameter 2.5 ψJB Junction-to-board characterization parameter 41.1 RθJCbot Junction-to-case (bottom) thermal resistance 11.1 (1) 4 °C/W For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953. Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated Product Folder Links: TPS61291 TPS61291 www.ti.com SLVSBX9A – SEPTEMBER 2014 – REVISED SEPTEMBER 2014 6.5 Electrical Characteristics TA = –40°C to 85°C. Typical values are at TA = 25°C (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT SUPPLY VIN IQ Startup voltage VOUT = 3.3V, IOUT = 20mA Input voltage range Operating voltage range Quiescent current in boost mode VIN VOUT Quiescent current in bypass mode VIN 1.5 0.9 IOUT = 0 mA, VEN/BYP = VIN = 1.8 V, VOUT = 3.3V, device not switching 0.4 VEN/BYP = low, VIN = 3 V, IOUT = 0 mA V 5 1.5 5.7 9 0.015 0.5 μA μA ILkSW Leakage current into SW VEN/BYP = low, VIN = 1.2 V, VSW = 1.2 V 0.01 0.5 VUVLO Undervoltage lockout threshold VIN decreasing 0.65 0.9 Overtemperature protection TJ rising 140 °C 20 °C Overtemperature hysteresis V INPUTS IIN EN/BYP, input current EN/BYP = low or EN/BYP = VIN 0.01 VIN ≤ 1.5 V VIL EN/BYP, input low voltage 5 V > VIN > 1.5 V VIN ≤ 1.5 V VIH EN/BYP, input high voltage VIL VSEL, input low voltage VEN/BYP = high VIH VSEL, input high voltage VEN/BYP = high IIN VSEL, input current VEN/BYP = high, VSEL = VOUT = 3V 5 V > VIN > 1.5 V 0.1 μA 0.2 × VIN V 0.3 0.8 × VIN V 1.2 0.3 V VOUT 0.3 V 0.01 μA 0.1 POWER SWITCHES RDS(ON) ISW Rectifying switch on resistance VOUT = 3.3 V 0.6 Ω Main switch on resistance VOUT = 3.3 V 0.4 Ω Bypass switch on resistance VIN = 1.8V, IOUT = 50 mA, EN/BYP = low 1.2 Switch current limit VOUT = 3.3V Output voltage accuracy VIN = 1.8V, IOUT = 10 mA, VOUT 3.3V, 3.0V, 2.5V, EN/BYP = high Line regulation VOUT = 3.3V, VIN = 2V to 3.0V, IOUT = 50 mA, EN/BYP = high Load regulation VIN = 2V, VOUT = 3.3V, IOUT = 1 mA to 200 mA, EN/BYP = high Output overvoltage protection VOUT rising, EN/BYP = high Ω 700 1000 1300 mA -2 +1 +4 % OUTPUT VOUT VOVP +0.15 %/V -0.007 %/mA 5.4 Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated Product Folder Links: TPS61291 V 5 TPS61291 SLVSBX9A – SEPTEMBER 2014 – REVISED SEPTEMBER 2014 www.ti.com 6.6 Typical Characteristics 0.14 1 VIN = 1.8V VIN = 3.3V 0.8 Quiescent Current IQ into VIN [mA] Bypass Mode Quiescent Current IQ [mA] 0.12 VIN = 1.8V VIN = 2.5V 0.9 0.1 0.08 0.06 0.04 VIN = 2.5V 0.7 0.6 0.5 0.4 0.3 0.2 0.02 0.1 0 0 -40 -20 0 20 40 60 80 100 -40 -20 0 Temperature T A [°C] 20 40 60 80 C001 EN/BYP = low VSEL = low IOUT = 0mA Figure 1. Quiescent Current IQ into VIN Pin in Bypass Mode C001 EN/BYP = high 1.6 VIN 1.8V VOUT = 2.6V VOUT = 3.1V 7 1.4 VOUT = 3.4V 1.2 6 RDSON Bypass Switch [W] Quiescent Current IQ into VOUT [mA] Boost mode operation Device not switching Figure 2. Quiescent Current IQ into VIN Pin in Boost Mode 8 5 4 3 1 0.8 0.6 2 0.4 1 0.2 0 0 -40 -20 0 20 40 60 80 -40 100 -20 0 EN/BYP = high IOUT = 0mA 40 60 80 Boost mode operation Device not switching 100 C001 Figure 3. Quiescent Current IQ into VOUT Pin in Boost Mode Figure 4. RDSON Bypass Switch 1 1 0.9 0.9 0.8 0.8 0.7 0.7 RDSON Rectifier Switch [W] RDSON Main Switch [W ] 20 Temperature T A [°C] Temperature T A [°C]] 0.6 0.5 0.4 0.3 0.6 0.5 0.4 0.3 0.2 0.2 0.1 0.1 0 0 -40 -20 0 20 40 60 80 100 -40 -20 0 20 40 60 80 100 Temperature T A [°C] Temperature T A [°C] VOUT = 3.3V Figure 5. RDSON Main Switch 6 100 Temperature TA [°C] C001 VOUT = 3.3V Figure 6. RDSON Rectifier Switch Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated Product Folder Links: TPS61291 TPS61291 www.ti.com SLVSBX9A – SEPTEMBER 2014 – REVISED SEPTEMBER 2014 7 Detailed Description 7.1 Overview The TPS61291 provides two operating modes: high efficiency boost mode to generate an output voltage higher than the input voltage and bypass mode, which connects the output of the device directly to the input. 7.2 Functional Block Diagram Bypass Switch P VIN SW VOUT N Rectifying Switch VOUT Driver VIN N Bypass Switch Control Control Logic EN/BYP Main Switch Current Sense Startup Circuit VIN Undervoltage Lockout Overvoltage Protection BYP/EN Reference Vref Vref GND Voltage Error Amplifier voltage selection logic Thermal Shutdown VSEL integrated FB divider network with disconnect 7.3 Feature Description 7.3.1 Bypass / Boost Mode Operation EN/BYP The EN/BYP pin selects the operating mode of the device. With the EN/BYP pin pulled low, the device operates in bypass mode. With a high level on the EN/BYP pin, the device operates as a boost converter. The EN/BYP pin is usually controlled by an I/O pin of a MCU, powered from the output of the TPS61291 and should not be left floating. See Figure 8. See also sections Boost Mode Operation and Bypass Mode Operation for more detailed descriptions. Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated Product Folder Links: TPS61291 7 TPS61291 SLVSBX9A – SEPTEMBER 2014 – REVISED SEPTEMBER 2014 www.ti.com Feature Description (continued) 7.3.2 Output Voltage Selection VSEL In boost mode operation, the device supports three internally set output voltages: 2.5V, 3V and 3.3V. Leaving the VSEL pin open sets the output voltage to 2.5V, VSEL = VOUT to 3.0V and VSEL= GND to 3.3V. The VSEL pin condition is detected during the startup of the boost converter and internally latched. For proper operation, it must be connected to either GND, VOUT or left floating. Depending on the VSEL condition, an integrated feedback divider network is selected. Changing the VSEL pin condition during operation does not change the output voltage. 7.3.3 Feedback Divider Disconnect In boost mode operation, the integrated feedback divider network, which is required for regulation, is connected to the VOUT pin. To achieve the low quiescent current in bypass mode, the integrated feedback divider network is disconnected from the output pin VOUT. 7.3.4 Undervoltage Lockout An undervoltage lockout function stops the operation of the boost converter if the input voltage drops below the undervoltage lockout threshold. This function is implemented in order to prevent malfunction of the boost converter. The undervoltage lockout function has no control of the bypass switch. 7.3.5 Overtemperature Protection The device has a built-in temperature sensor which monitors the internal junction temperature in boost mode operation. If the junction temperature exceeds the threshold (140 °C typical), the device stops operating. As soon as the junction temperature has decreased below the programmed threshold, it starts operating again. There is a built-in hysteresis to avoid unstable operation at IC temperatures at the overtemperature threshold. The overtemperature protection is not active in bypass mode operation. 7.3.6 Overvoltage Protection In boost mode operation (EB/BYP = high), the device features a redundant over voltage protection circuit (OVP), which is independent from the reference, the regulation loop and feedback divider network. The redundant over voltage protection circuit limits the output voltage to typically 5.4V. The over voltage protection can only limit the output voltage in boost mode operation, when the input voltage VIN is smaller than the output voltage VOUT. 7.4 Device Functional Modes 7.4.1 Boost Mode Operation The device is enabled and operates in boost mode operation when the EN/BYP pin is set high. The bypass switch is turned off once the boost converter has started switching. In boost mode operation, 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 300 mA and adjusting the offset of this inductor current depending on the output load. If the required average input current is lower than the average inductor current defined by this constant ripple, the inductor current goes discontinuous to keep the efficiency high at low load conditions. To achieve high efficiency, the power stage is realized as a synchronous boost topology. IL Continuous Current Operation IIN Discontinuous Current Operation Ilpp = 300 mA (typ.) Ilpp = 300 mA (typ.) t Figure 7. Hysteretic Current Operation 8 Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated Product Folder Links: TPS61291 TPS61291 www.ti.com SLVSBX9A – SEPTEMBER 2014 – REVISED SEPTEMBER 2014 Device Functional Modes (continued) The output voltage VOUT is monitored via the integrated 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. The hysteretic current mode architecture allows fast response to load variations. 7.4.2 Bypass Mode Operation The TPS61291 includes a P-channel MOSFET (Bypass Switch) between the VIN and VOUT pins. When the IC is disabled (EN/BYP = low), bypass mode is activated to provide a direct, low impedance connection from the input voltage (at the VIN pin) to the load (VOUT). The bypass switch is not impacted by undervoltage lockout, or thermal shutdown. The bypass switch is not current-limit controlled. In bypass operation, the OVP circuit is disabled. 7.4.3 Controlled Transition into Bypass Mode When changing from boost mode into bypass mode, the output capacitor is usually charged up to a higher voltage than the battery voltage VBAT. In order to prevent current flowing from the output capacitor COUT via the bypass switch into the battery (reverse battery current), the internal bypass control circuit delays the bypass switch activation until the output voltage VOUT has decreased to the input voltage level. 7.4.4 Operation at Output Overload If the peak inductor current reaches the internal switch current limit threshold in boost mode operation, the main switch is turned off to stop a further increase of the input current. In this case the output voltage will decrease since the device cannot 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 to flow through it. Because this diode cannot be turned off, the load current is only limited by the remaining DC resistance. As soon as the overload condition is removed, the converter automatically resumes normal operation and enters the appropriate soft start mode depending on the operating conditions. 7.4.5 Startup After the EN/BYP pin is tied high, the device starts to operate. If 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 switch current is limited. As soon as the device has built up the output voltage to about 1.8 V, high enough for supplying the control circuit, the device switches to its normal hysteretic current mode operation. Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated Product Folder Links: TPS61291 9 TPS61291 SLVSBX9A – SEPTEMBER 2014 – REVISED SEPTEMBER 2014 www.ti.com 8 Applications and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 8.1 Application Information The TPS61291 is a boost converter with pin selectable output voltages and an integrated bypass mode. In bypass operation, the device provides a direct path from the input to the system and allows a low power micro controller (MCU) to operate directly from a single 3V Li-MnO2 battery or dual alkaline battery cells. In bypass mode, the quiescent current consumption is typically only 15nA and supports low power modes of MCUs such as the MSP430. In boost mode operation, the device provides a regulated output voltage (e.g. 3.3V) to supply circuits which require a higher voltage than provided by the battery. See Figure 8. The device also extends battery life in applications which can run partially directly from the battery, but need a boost conversion to maintain sufficient system voltage when the battery voltage drops due to discharge. In this case, the system runs off the battery in bypass mode operation until the battery voltage trips the minimum system operating voltage. Then the system turns on the boost converter, providing a sufficient output voltage down to the cut off voltage of the battery. See Figure 9 and Figure 26. 8.2 Typical Application TPS61291 L = 3.3mH 2 x 1.5V Alkaline / 1 x 3V Li-MnO2 + + - Subsystem VOUT = Step up converter VOUT VBAT / 3.3V VIN COUT 22mF Bypass CIN 10mF + - SW VCC = 3.3V MCU (VCC = VBAT or 3.3V) VSEL GND EN/BYP Figure 8. Typical Application Circuit with Regulated 3.3V VOUT / VBAT System TPS61291 L = 3.3mH 2 x 1.5V Alkaline / 1 x 3V Li-MnO2 + + - VBAT CIN + - NC SW VOUT = Step up V / 2.5V BAT converter VOUT VIN COUT Bypass MCU + ADC Subsystem VSEL GND EN/BYP EN/BYP set high @ VBAT = 2.2V Minimum VCC for System: 2.2V Bypass Mode: VOUT = VBAT (for VBAT > 2.2V) Boost Mode: VOUT = 2.5V (for VBAT < 2.2V) Figure 9. Bypass Mode / Boost Mode Operation to Maintain Sufficient System Voltage 8.2.1 Design Requirements The TPS61291 is a highly integrated boost converter. The output voltage is set internally via a VSEL pin without any additional components. For operation, only an input capacitor, output capacitor, and an inductor are required. Table 1 shows the components used for the application characteristic curves. 10 Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated Product Folder Links: TPS61291 TPS61291 www.ti.com SLVSBX9A – SEPTEMBER 2014 – REVISED SEPTEMBER 2014 Typical Application (continued) Table 1. Components for Application Characteristic Curves (1) (1) Reference Description TPS61291 Low Iq Boost Converter with Bypass Operation Value Manufacturer Texas Instruments CIN Input capacitor 10µF Murata GRM219R61A106KE44D COUT Output capacitor 22µF Murata GRM21BR60J226ME39L L Inductor 3.3µH Coilcraft LPS3314 3R3 See the Third-Party Products Disclaimer in the Device Support section. 8.2.2 Detailed Design Procedure The external components have to fulfill the needs of the application but also the stability criteria of the device's control loop. The TPS61291 is optimized to work within a range of L and C combinations. The LC output filter inductance and capacitance must be considered together. The output capacitor sets the corner frequency of the converter while the inductor creates a Right-Half-Plane-Zero degrading the stability of the converter. Consequently with a larger inductor a bigger capacitor has to be used to guarantee a stable loop. Table 2 shows the output filter component selection. Table 2. Recommended LC Output Filter Combinations Output voltage [V] 3.3 / 3.0 2.5 (1) (2) (3) Output capacitor value [µF] (2) Inductor value [µH] (1) 22 22 + 10 2 x 22 (3) √ √ √ √ √ (3) √ √ 3.3 √ 4.7 2.2 √ 3.3 Inductor tolerance and current de-rating is anticipated. The effective inductance can vary by 20% and -30%. Capacitance tolerance and bias voltage de-rating is anticipated. The effective capacitance can vary by 20% and -50%. This LC combination is the standard value and recommended for most applications. 8.2.2.1 Inductor Selection The device is optimized to operate with a 3.3µH inductor value. Other inductor values can be used, per Table 2. The maximum inductor current can be approximated by the ILMAX, from Equation 1. For proper operation, the inductor needs to be rated for a saturation current which is higher than the switch current limit of typically 1A. Table 3 lists inductors that have been tested with the TPS61291. V ´I IL max : = OUT OUT + 150 mA continuous current operation 0.8 ´ VIN IL max : = 300 mA discontinuous current operation (1) Table 3. List of Inductors (1) (1) INDUCTANCE DIMENSIONS [mm3] TYPE 3.3 3.3 x 3.3 x 1.3 LPS3314 3.3 2.95 x 2.95 x 1.4 LPS3015 3.3 3 x 2.5 x 1.5 VLF302515 TDK 3.3 2 x 2 x 1.2 MDMK2020T3R3M Taiyo Yuden 3.3 2.5 x 2.0 x 1.2 DFE252012 Toko 3.3 3.0 x 3.0 x 1.5 74438335033 Würth SUPPLIER Coilcraft See the Third-Party Products Disclaimer in the Device Support section. Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated Product Folder Links: TPS61291 11 TPS61291 SLVSBX9A – SEPTEMBER 2014 – REVISED SEPTEMBER 2014 www.ti.com 8.2.2.2 Input and Output Capacitor Selection For best output and input voltage filtering, low ESR X5R or X7R ceramic capacitors are recommended. The input capacitor minimizes input voltage ripple, suppresses input voltage spikes and provides a stable system rail for the device. At least a 10μF or larger input capacitor is recommended for operation. In applications in which the power source (e.g. certain battery chemistries) shows an internal resistance characteristic, a larger input capacitor might be used to buffer the supply voltage for the TPS61291. The recommended typical output capacitor value is 22 μF and can vary as outlined in the output filter selection Table 2. 12 Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated Product Folder Links: TPS61291 TPS61291 www.ti.com SLVSBX9A – SEPTEMBER 2014 – REVISED SEPTEMBER 2014 100 100 95 95 90 90 85 85 Efficiency [%] Efficiency [%] 8.2.3 Application Curves 80 75 VIN = 1.2V 70 80 75 VIN = 1.2V 70 VIN = 1.8V VIN = 1.8V 65 VIN = 2.5V 60 VIN = 3.0V VIN = 2.5V 65 VIN = 2.7V 60 55 55 50 0.01 0.1 1 10 50 0.01 100 0.1 1 10 100 Output Current IOUT [mA] Output Current IOUT [mA] C002 C002 EN/BYP = high L = 3.3µH VSEL = GND EN/BYP = high L = 3.3µH VSEL = VOUT Figure 11. Efficiency vs IOUT, VOUT = 3.0V Figure 10. Efficiency vs IOUT, VOUT = 3.3V 100 3.399 95 Output Voltage VOUT [V] 90 Efficiency [%] 85 80 75 VIN = 1.2V 70 VIN = 1.8V 65 3.366 3.333 VIN = 1.2V VIN = 1.8V VIN = 2.2V 3.300 VIN = 2.5V 60 VIN = 3.0V 55 50 0.01 0.1 1 10 3.267 0.01 100 0.1 Output Current IOUT [mA] 1 10 100 Output Current IOUT[mA] C006 C001 EN/BYP = high L = 3.3µH VSEL = open 3.090 2.575 3.060 2.550 3.030 VIN = 1.2V 3.000 L = 3.3µH 2.525 VIN = 1.2V VIN = 1.8V 2.500 VIN = 1.8V VIN = 2.2V VIN = 2.5V 2.970 0.01 0.1 1 10 2.475 0.01 100 Output Current IOUT [mA] 0.1 1 10 L = 3.3µH 100 Output Current IOUT [mA] C005 EN/BYP = high VSEL = GND Figure 13. Output Voltage vs Output Current VOUT = 3.3V Output Voltage VOUT [V] Output Voltage VOUT [V] Figure 12. Efficiency vs IOUT, VOUT = 2.5V EN/BYP = high VSEL = VOUT Figure 14. Output Voltage vs Output Current VOUT = 3.0V C004 EN/BYP = high L = 3.3µH VSEL = open Figure 15. Output Voltage vs Output Current VOUT = 2.5V Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated Product Folder Links: TPS61291 13 TPS61291 SLVSBX9A – SEPTEMBER 2014 – REVISED SEPTEMBER 2014 www.ti.com 35 0.600 T A = 25°C T A = 85°C 25 0.400 0.300 Input Current IIN [uA] Maximum Output Current IOUTMAX [A] T A = -40°C 30 0.500 VOUT = 2.5V VOUT = 3.0V VOUT = 3.3V 0.200 20 15 10 0.100 5 0.000 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 0.9 1.4 1.9 Input Voltage VIN [V] 2.4 2.9 Input Voltage VIN [V] C001 EN/BYP = high L = 3.3µH ISW = 1000mA (typical) Boost mode operation Figure 16. Maximum Output Current VOUT = 3.3 V IOUT = 0 mA L = 3.3 µH COUT = 22 µF Device switching Figure 17. Supply Current vs. VIN, VOUT = 3.3V, IOUT = 0mA 35 30 T A = 25°C T A = 25°C T A = -40°C 30 T A = -40°C 25 T A = 85°C T A = 85°C Input Current IIN [uA] Input Current IIN [uA] 25 20 15 20 15 10 10 5 5 0 0 0.9 1.4 1.9 2.4 2.9 0.9 1.4 Input Voltage VIN [V] VOUT = 3.0 V IOUT = 0 mA L = 3.3 µH COUT = 22 µF Device switching Figure 18. Supply Current vs. VIN, VOUT = 3.0V, IOUT = 0mA VIN = 2.0 V VOUT = 3.3 V L = 3.3 µH IOUT = 15mA VOUT = 2.5 V IOUT = 0 mA 2.4 L = 3.3 µH COUT = 22 µF Device switching Figure 19. Supply Current vs. VIN, VOUT = 2.5V, IOUT = 0mA COUT = 22 µF VSEL = GND EN/BYP = high Figure 20. Discontinuous Conduction Mode Operation, VOUT = 3.3V 14 1.9 Input Voltage VIN [V] VIN = 1.8 V VOUT = 3.3 V VSEL = GND L = 3.3 µH COUT = 22 µF IOUT = 150 mA EN/BYP = high Figure 21. Continuous Conduction Mode Operation, VOUT = 3.3V Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated Product Folder Links: TPS61291 TPS61291 www.ti.com SLVSBX9A – SEPTEMBER 2014 – REVISED SEPTEMBER 2014 VIN = 1.8V VOUT = 3.3V L = 3.3µH COUT = 22 µF VSEL = GND ILOAD 20mA /150mA VIN = 1.8V VOUT = 3.3V Figure 22. Load Transient Response L = 3.3µH COUT = 22 µF VSEL = GND ILOAD 1mA/200mA Figure 23. AC Load Sweep Boost operation Bypass switch activation when VOUT is discharged to VIN level Bypass mode VIN = 2.5V/3V VOUT = 3.3V L = 3.3µH VSEL = GND COUT = 22 µF Load =100Ω Figure 24. Line Transient Response VIN = 2.0V VOUT = 3.3V L = 3.3µH VSEL = GND COUT = 22 µF RLOAD = 1kΩ Figure 25. Boost Mode / Bypass Mode Transition VIN VOUT = 2.5V VOUT tracks VIN VIN < 2.2V EN/BYP control IL VIN = 0.9V to 3V VOUT = 2.5V VSEL = Open ILOAD = 5mA EN/BYP externally controlled Bypass / Boost mode operation VIN = 2.0V VOUT = 3.3V Figure 26. Bypass / Boost Mode Operation L = 3.3µH VSEL = GND COUT = 22 µF RLOAD = 100Ω Figure 27. Startup in Boost Mode Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated Product Folder Links: TPS61291 15 TPS61291 SLVSBX9A – SEPTEMBER 2014 – REVISED SEPTEMBER 2014 www.ti.com 9 Power Supply Recommendations The input power supply needs to have a current rating according to the supply voltage, output voltage and output current of the TPS61291. 10 Layout 10.1 Layout Guidelines As for all switching power supplies, the layout is an important step in the design. Care must be taken in board layout to get the specified performance. If the layout is not carefully done, the regulator could show poor line and/or load regulation, stability issues as well as EMI problems. It is critical to provide a low inductance, low impedance ground path. Therefore, use wide and short traces for the main current paths. In a boost converter, the ripple current on the output is larger than the ripple current on the input. The output capacitor needs to be placed as close as possible between the VOUT and the GND pins. The input capacitor should be placed as close as possible to the VIN and GND pins. Place the inductor close by the IC and connect it with short and thick traces to the IC. Avoid current loops to minimize radiated noise and stray fields. The exposed thermal pad of the package and the GND pin must be connected. See Figure 28 for the recommended PCB layout. 10.2 Layout Example 2 Area: ~ 51 mm VIN VOUT GND U1 CIN L GND COUT Figure 28. Recommended PCB Layout 16 Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated Product Folder Links: TPS61291 TPS61291 www.ti.com SLVSBX9A – SEPTEMBER 2014 – REVISED SEPTEMBER 2014 11 Device and Documentation Support 11.1 Device Support 11.1.1 Third-Party Products Disclaimer TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER ALONE OR IN COMBINATION WITH ANY TI PRODUCT OR SERVICE. 11.2 Documentation Support 11.2.1 Related Documentation TPS61291EVM-569 User's Guide, SLVUA29 11.3 Trademarks 11.4 Electrostatic Discharge Caution 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. 11.5 Glossary SLYZ022 — TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 12 Mechanical, Packaging, and Orderable Information The following pages include mechanical packaging and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated Product Folder Links: TPS61291 17 PACKAGE OPTION ADDENDUM www.ti.com 28-Sep-2014 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (°C) Device Marking (4/5) TPS61291DRVR ACTIVE SON DRV 6 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 PC4I TPS61291DRVT ACTIVE SON DRV 6 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 PC4I (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. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com 28-Sep-2014 In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 1-Oct-2014 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant TPS61291DRVR SON DRV 6 3000 180.0 8.4 2.3 2.3 1.15 4.0 8.0 Q2 TPS61291DRVT SON DRV 6 250 180.0 8.4 2.3 2.3 1.15 4.0 8.0 Q2 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 1-Oct-2014 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) TPS61291DRVR SON DRV 6 3000 210.0 185.0 35.0 TPS61291DRVT SON DRV 6 250 210.0 185.0 35.0 Pack Materials-Page 2 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. 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