TPS61087 Actual Size 3 mm x 3 mm www.ti.com SLVS821C – MAY 2008 – REVISED JULY 2013 650 kHz/1.2 MHz, 18.5 V STEP-UP DC-DC CONVERTER WITH 3.2 A SWITCH Check for Samples: TPS61087 FEATURES 1 • • • • • • • APPLICATIONS 2.5 V to 6 V Input Voltage Range 18.5 V Boost Converter With 3.2 A Switch Current 650 kHz/1.2 MHz Selectable Switching Frequency Adjustable Soft-Start Thermal Shutdown Undervoltage Lockout 10-Pin QFN and thin QFN Packages • • • • • • • Handheld Devices GPS Receiver Digital Still Camera Portable Applications DSL Modem PCMCIA Card TFT LCD Bias Supply DESCRIPTION The TPS61087 is a high frequency, high efficiency DC to DC converter with an integrated 3.2 A, 0.13 Ω power switch capable of providing an output voltage up to 18.5 V. The selectable frequency of 650 kHz or 1.2 MHz allows the use of small external inductors and capacitors and provides fast transient response. The external compensation allows optimizing the application for specific conditions. A capacitor connected to the soft-start pin minimizes inrush current at startup. L 3.3 mH VIN 2.5 V to 6 V Cin 2* 10 mF 16 V 8 Cby 1 mF 16 V 3 9 4 5 IN SW EN SW FREQ FB AGND COMP PGND SS TPS61087 D SL22 6 VS 15 V/500 mA R1 200 kW 7 Cout 4* 10 mF 25 V 2 R2 18 kW 1 Rcomp 100 kW 10 Css 100 nF Ccomp 820 pF 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 © 2008–2013, Texas Instruments Incorporated TPS61087 SLVS821C – MAY 2008 – REVISED JULY 2013 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. ORDERING INFORMATION (1) (1) (2) (2) TA ORDERING PACKAGE PACKAGE MARKING –40 to 85°C TPS61087DRC QFN-10 (DRC) PMOQ TPS61087DSC QFN-10 (DSC) PMWI The DRC package is available taped and reeled. 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. ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) (1) VALUE UNIT Input voltage range IN (2) –0.3 to 7.0 V Voltage range on pins EN, FB, SS, FREQ, COMP –0.3 to 7.0 V Voltage on pin SW –0.3 to 20 V ESD rating HBM 2 kV ESD rating MM 200 V ESD rating CDM 500 V Continuous power dissipation See Dissipation Rating Table Operating junction temperature range –40 to 150 °C Storage temperature range –65 to 150 °C (1) (2) 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 All voltage values are with respect to network ground terminal. DISSIPATION RATINGS (1) (1) (2) (2) PACKAGE TA ≤ 25°C POWER RATING TA = 70°C POWER RATING TA = 85°C POWER RATING QFN 1.74 W 0.96 W 0.70 W PD = (TJ – TA)/RθJA. The exposed thermal die is soldered to the PCB using thermal vias. For more information, see the Texas Instruments Application report SLMA002 regarding thermal characteristics of the PowerPAD package. RECOMMENDED OPERATING CONDITIONS MIN VIN Input voltage range VS Boost output voltage range TA Operating free-air temperature TJ Operating junction temperature 2 Submit Documentation Feedback TYP MAX UNIT 2.5 6 V VIN + 0.5 18.5 V –40 85 °C –40 125 °C Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS61087 TPS61087 www.ti.com SLVS821C – MAY 2008 – REVISED JULY 2013 ELECTRICAL CHARACTERISTICS VIN = 5 V, EN = VIN, VS = 15 V, TA = –40°C to 85°C, typical values are at TA = 25°C (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT 6 V 75 100 μA 1 μA V SUPPLY VIN Input voltage range IQ Operating quiescent current into IN Device not switching, VFB = 1.3 V ISDVIN Shutdown current into IN EN = GND VUVLO Under-voltage lockout threshold VIN falling 2.4 VIN rising 2.5 TSD Thermal shutdown TSDHYS Thermal shutdown hysteresis 2.5 Temperature rising V 150 °C 14 °C LOGIC SIGNALS EN, FREQ VIN = 2.5 V to 6.0 V 2 VIH High level input voltage VIL Low level input voltage VIN = 2.5 V to 6.0 V 0.5 V IINLEAK Input leakage current EN = FREQ = GND 0.1 μA 18.5 V 1.246 V only valid for EN, VIN = 2.5 V to 4.3 V V 1.6 BOOST CONVERTER VS Boost output voltage VIN + 0.5 VFB Feedback regulation voltage 1.230 gm Transconductance error amplifier IFB Feedback input bias current rDS(on) N-channel MOSFET on-resistance ISWLEAK SW leakage current ILIM N-Channel MOSFET current limit ISS Soft-start current fS Oscillator frequency 1.238 μA/V 107 VFB = 1.238 V 0.1 μA VIN = VGS = 5 V, ISW = current limit 0.13 0.18 VIN = VGS = 3V, ISW = current limit 0.16 0.23 3.2 4.0 4.8 A 7 10 13 μA MHz EN = GND, VSW = VIN = 6.0V VSS = 1.238 V 2 FREQ = VIN 0.9 1.2 1.5 FREQ = GND 480 650 820 Line regulation VIN = 2.5 V to 6.0 V, IOUT = 10 mA Load regulation VIN = 5.0 V, IOUT = 1 mA to 1 A Product Folder Links: TPS61087 μA kHz 0.0002 %/V 0.11 %/A Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Ω 3 TPS61087 SLVS821C – MAY 2008 – REVISED JULY 2013 www.ti.com PIN ASSIGNMENT DRC, DSC PACKAGE (TOP VIEW) COMP SS FB EN FREQ Thermal Pad IN AGND SW PGND SW 10-PIN 3mm x 3mm x 1mm QFN PIN FUNCTIONS PIN NAME NO. I/O DESCRIPTION COMP 1 I/O FB 2 I Feedback pin 3 I Shutdown control input. Connect this pin to logic high level to enable the device EN AGND PGND SW Compensation pin 4, Thermal Pad Analog ground 5 Power ground 6, 7 IN 8 FREQ 9 SS 10 Switch pin Input supply pin I Frequency select pin. The power switch operates at 650 kHz if FREQ is connected to GND and at 1.2 MHz if FREQ is connected to IN Soft-start control pin. Connect a capacitor to this pin if soft-start needed. Open = no soft-start TABLE OF GRAPHS FIGURE IOUT(max) Maximum load current vs. Input voltage at High frequency (1.2 MHz) Figure 1 IOUT(max) Maximum load current vs. Input voltage at Low frequency (650 kHz) Figure 2 η Efficiency vs. Load current, VS = 15 V, VIN = 5 V Figure 3 η Efficiency vs. Load current, VS = 9 V, VIN = 3.3 V Figure 4 PWM switching - discontinuous conduction Figure 5 PWM switching - continuous conduction Figure 6 Load transient response at High frequency (1.2 MHz) Figure 7 Load transient response at Low frequency (650 kHz) Figure 8 Supply current vs. Supply voltage Figure 10 Oscillator frequency vs. Load current Figure 11 Oscillator frequency vs. Supply voltage Figure 12 Soft-start Figure 9 The typical characteristics are measured with the inductors 7447789003 3.3 µH (high frequency) or 74454068 6.8 µH (low frequency) from Wurth and the rectifier diode SL22. 4 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS61087 TPS61087 www.ti.com SLVS821C – MAY 2008 – REVISED JULY 2013 TYPICAL CHARACTERISTICS MAXIMUM LOAD CURRENT vs INPUT VOLTAGE MAXIMUM LOAD CURRENT vs INPUT VOLTAGE 3.0 3.0 fS = 1.2 Mhz 2.5 VOUT = 9 V 2.0 VOUT = 12 V 1.5 VOUT = 15 V 1.0 VOUT = 18.5 V 0.5 IOUT - Maximum Load Current - A IOUT - Maximum Load Current - A fS = 650 kHz 2.5 2.0 VOUT = 9 V VOUT = 12 V 1.5 1.0 VOUT = 18.5 V 0.5 VOUT = 15 V 0.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 0.0 2.5 6.0 EFFICIENCY vs LOAD CURRENT EFFICIENCY vs LOAD CURRENT 90 90 L = 3.3 mH 5.0 5.5 6.0 fS = 650 kHz L = 6.8 mH 80 fS = 1.2 Mhz fS = 650 kHz 70 Efficiency - % L = 6.8 mH Efficiency - % 4.5 Figure 2. 100 60 50 40 fS = 1.2 Mhz L = 3.3 mH 60 50 40 30 30 20 VIN = 5 V VS = 15 V 10 0 0.0 0.1 4.0 Figure 1. 100 70 3.5 VIN - Input Voltage - V VIN - Input Voltage - V 80 3.0 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 IOUT - Load Current - A 20 VIN = 3.3 V VS = 9 V 10 0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 IOUT - Load Current - A Figure 3. Figure 4. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS61087 5 TPS61087 SLVS821C – MAY 2008 – REVISED JULY 2013 www.ti.com TYPICAL CHARACTERISTICS (continued) PWM SWITCHING DISCONTINUOUS CONDUCTION MODE PWM SWITCHING CONTINUOUS CONDUCTION MODE VSW 10 V/div VSW 10 V/div VS_AC 50 mV/div VS_AC 50 mV/div VIN = 5 V VS = 15 V/2 mA FREQ = VIN Il 1 A/div VIN = 5 V VS = 15 V/500 mA FREQ = VIN IL 500 mA/div 200 ns/div Figure 6. 200 ns/div Figure 5. LOAD TRANSIENT RESPONSE HIGH FREQUENCY (1.2 MHz) LOAD TRANSIENT RESPONSE LOW FREQUENCY (650 kHz) VIN = 5 V VS = 15 V VIN = 5 V VS = 15 V VS_AC 100 mV/div COUT = 40 mF IOUT = 100 mA - 500 mA L = 3.3 mH Rcomp = 150 kW Ccomp = 820 pF COUT = 40 mF L = 6.8 mH Rcomp = 110 kW Ccomp = 1 nF VS_AC 100 mV/div IOUT = 100 mA - 500 mA IOUT 200 mA/div IOUT 200 mA/div 200 ms/div 200 ms/div Figure 8. Figure 7. 6 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS61087 TPS61087 www.ti.com SLVS821C – MAY 2008 – REVISED JULY 2013 TYPICAL CHARACTERISTICS (continued) SUPPLY CURRENT vs SUPPLY VOLTAGE SOFT-START 2.0 ICC - Supply Current - mA EN 5 V/div VIN = 5 V VS = 15 V/500 mA VS 5 V/div CSS = 100 nF IL 1 A/div 1.8 SWITCHING fS = 1.2 Mhz 1.6 L = 3.3 mH 1.4 SWITCHING fS = 650 kHz 1.2 L = 6.8 mH 1.0 0.8 0.6 0.4 0.2 2 ms/div NOT SWITCHING 0 2.5 3.0 3.5 4.0 4.5 5.0 VCC - Supply Voltage - V Figure 9. Figure 10. OSCILLATOR FREQUENCY vs LOAD CURRENT OSCILLATOR FREQUENCY vs SUPPLY VOLTAGE 1600 5.5 6.0 1400 VS = 15 V / 200 mA FREQ = VIN 1200 L = 3.3 mH fS - Oscillator Frequency - kHz fS - Oscillator Frequency - kHz 1400 1200 1000 800 FREQ = GND L = 6.8 mH 600 400 VIN = 5 V VS = 15 V 200 0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 FREQ = VIN L = 3.3 mH 1000 800 600 FREQ = GND L = 6.8 mH 400 200 1.0 0 2.5 IOUT - Load Current - mA Figure 11. 3 3.5 4 4.5 5 VCC - Supply Voltage - V 5.5 6 Figure 12. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS61087 7 TPS61087 SLVS821C – MAY 2008 – REVISED JULY 2013 www.ti.com DETAILED DESCRIPTION VIN VS EN SS IN SW FREQ SW Current limit and Soft Start tOFF Generator AGND Bias Vref = 1.238V UVLO Thermal Shutdown tON PWM Generator Gate Driver of Power Transistor COMP GM Amplifier FB Vref PGND Figure 13. Block Diagram The boost converter is designed for output voltages up to 18.5 V with a switch peak current limit of 3.2 A minimum. The device, which operates in a current mode scheme with quasi-constant frequency, is externally compensated for maximum flexibility and stability. The switching frequency is selectable between 650 kHz and 1.2 MHz and the minimum input voltage is 2.5 V. To limit the inrush current at start-up a soft-start pin is available. TPS61087 boost converter’s novel topology using adaptive off-time provides superior load and line transient responses and operates also over a wider range of applications than conventional converters. The selectable switching frequency offers the possibility to optimize the design either for the use of small sized components (1.2 MHz) or for higher system efficiency (650 kHz). However, the frequency changes slightly because the voltage drop across the rDS(on) has some influence on the current and voltage measurement and thus on the on-time (the off-time remains constant). The converter operates in continuous conduction mode (CCM) as soon as the input current increases above half the ripple current in the inductor, for lower load currents it switches into discontinuous conduction mode (DCM). If the load is further reduced, the part starts to skip pulses to maintain the output voltage. 8 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS61087 TPS61087 www.ti.com SLVS821C – MAY 2008 – REVISED JULY 2013 Design Procedure The first step in the design procedure is to verify that the maximum possible output current of the boost converter supports the specific application requirements. A simple approach is to estimate the converter efficiency, by taking the efficiency numbers from the provided efficiency curves or to use a worst case assumption for the expected efficiency, e.g. 90%. 1. Duty cycle, D: D = 1- VIN ×h VS (1) 2. Maximum output current, Iout(max) : DI æ I out (max) = ç I LIM (min) - L 2 è ö ÷ × (1 - D ) ø (2) 3. Peak switch current in application, Iswpeak : I swpeak = I DI L + out 2 1- D (3) with the inductor peak-to-peak ripple current, ΔIL DI L = VIN × D fS × L (4) and VIN Minimum input voltage VS Output voltage ILIM(min) Converter switch current limit (minimum switch current limit = 3.2 A) fS Converter switching frequency (typically 1.2 MHz or 650 kHz) L Selected inductor value η Estimated converter efficiency (please use the number from the efficiency plots or 90% as an estimation) The peak switch current is the steady state peak switch current that the integrated switch, inductor and external Schottky diode has to be able to handle. The calculation must be done for the minimum input voltage where the peak switch current is the highest. Soft-start The boost converter has an adjustable soft-start to prevent high inrush current during start-up. To minimize the inrush current during start-up an external capacitor, connected to the soft-start pin SS and charged with a constant current, is used to slowly ramp up the internal current limit of the boost converter. When the EN pin is pulled high, the soft-start capacitor CSS is immediately charged to 0.3 V. The capacitor is then charged at a constant current of 10 μA typically until the output of the boost converter VS has reached its Power Good threshold (roughly 98% of VS nominal value). During this time, the SS voltage directly controls the peak inductor current, starting with 0 A at VSS = 0.3 V up to the full current limit at VSS = 800 mV. The maximum load current is available after the soft-start is completed. The larger the capacitor the slower the ramp of the current limit and the longer the soft-start time. A 100 nF capacitor is usually sufficient for most of the applications. When the EN pin is pulled low, the soft-start capacitor is discharged to ground. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS61087 9 TPS61087 SLVS821C – MAY 2008 – REVISED JULY 2013 www.ti.com Inductor Selection The TPS61087 is designed to work with a wide range of inductors. The main parameter for the inductor selection is the saturation current of the inductor which should be higher than the peak switch current as calculated in the Design Procedure section with additional margin to cover for heavy load transients. An alternative, more conservative, is to choose an inductor with a saturation current at least as high as the maximum switch current limit of 4.8 A. The other important parameter is the inductor DC resistance. Usually the lower the DC resistance the higher the efficiency. It is important to note that the inductor DC resistance is not the only parameter determining the efficiency. Especially for a boost converter where the inductor is the energy storage element, the type and core material of the inductor influences the efficiency as well. At high switching frequencies of 1.2 MHz inductor core losses, proximity effects and skin effects become more important. Usually an inductor with a larger form factor gives higher efficiency. The efficiency difference between different inductors can vary between 2% to 10%. For the TPS61087, inductor values between 3 μH and 6 μH are a good choice with a switching frequency of 1.2 MHz, typically 3.3 μH. At 650 kHz we recommend inductors between 6 μH and 13 μH, typically 6.8 μH. Possible inductors are shown in Table 1. Typically, it is recommended that the inductor current ripple is below 35% of the average inductor current. Therefore, the following equation can be used to calculate the inductor value, L: 2 æ V ö æ V -V ö æ h ö L = ç IN ÷ × ç S IN ÷ × ç ÷ è VS ø è I out × f S ø è 0.35 ø (5) with VIN Minimum input voltage VS Output voltage Iout Maximum output current in the application fS Converter switching frequency (typically 1.2 MHz or 650 kHz) η Estimated converter efficiency (please use the number from the efficiency plots or 90% as an estimation) Table 1. Inductor Selection L (μH) SUPPLIER COMPONENT CODE SIZE (L×W×H mm) DCR TYP (mΩ) Isat (A) 4.2 Sumida CDRH5D28 4.7 5.7 × 5.7 × 3 23 2.2 Wurth Elektronik 7447785004 5.9 × 6.2 × 3.3 60 2.5 5 Coilcraft MSS7341 7.3 × 7.3 × 4.1 24 2.9 1.2 MHz 5 Sumida CDRH6D28 7×7×3 23 2.4 4.6 Sumida CDR7D28 7.6 × 7.6 × 3 38 3.15 4.7 Wurth Elektronik 7447789004 7.3 × 7.3 × 3.2 33 3.9 3.3 Wurth Elektronik 7447789003 7.3 × 7.3 × 3.2 30 4.2 744778910 7.3 × 7.3 × 3.2 51 2.2 650 kHz 10 10 Wurth Elektronik 10 Sumida CDRH8D28 8.3 × 8.3 × 3 36 2.7 6.8 Sumida CDRH6D26HPNP 7 × 7 × 2.8 52 2.9 6.2 Sumida CDRH8D58 8.3 × 8.3 × 6 25 3.3 10 Coilcraft DS3316P 12.95 × 9.40 × 5.08 80 3.5 10 Sumida CDRH8D43 8.3 × 8.3 × 4.5 29 4 6.8 Wurth Elektronik 74454068 12.7 × 10 × 4.9 55 4.1 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS61087 TPS61087 www.ti.com SLVS821C – MAY 2008 – REVISED JULY 2013 Rectifier Diode Selection To achieve high efficiency a Schottky type should be used for the rectifier diode. The reverse voltage rating should be higher than the maximum output voltage of the converter. The averaged rectified forward current Iavg , the Schottky diode needs to be rated for, is equal to the output current Iout : I avg = I out (6) Usually a Schottky diode with 2 A maximum average rectified forward current rating is sufficient for most applications. The Schottky rectifier can be selected with lower forward current capability depending on the output current Iout but has to be able to dissipate the power. The dissipated power, PD , is the average rectified forward current times the diode forward voltage, Vforward . PD = I avg × V forward (7) Typically the diode should be able to dissipate around 500mW depending on the load current and forward voltage. Table 2. Rectifier Diode Selection CURRENT RATING Iavg Vr Vforward/Iavg SUPPLIER COMPONENT CODE 2A 20 V 0.44 V / 2 A Vishay Semiconductor SL22 2A 20 V 0.5 V / 2 A Fairchild Semiconductor SS22 Setting the Output Voltage The output voltage is set by an external resistor divider. Typically, a minimum current of 50 μA flowing through the feedback divider gives good accuracy and noise covering. A standard low side resistor of 18 kΩ is typically selected. The resistors are then calculated as: VS R2 = VFB » 18k W 70 m A æ V ö R1 = R 2 × ç S - 1÷ è VFB ø R1 VFB VFB = 1.238V R2 (8) Compensation (COMP) The regulator loop can be compensated by adjusting the external components connected to the COMP pin. The COMP pin is the output of the internal transconductance error amplifier. Standard values of RCOMP = 16 kΩ and CCOMP = 2.7 nF will work for the majority of the applications. See Table 3 for dedicated compensation networks giving an improved load transient response. The following equations can be used to calculate RCOMP and CCOMP : RCOMP = 110 × VIN × VS × Cout L × I out CCOMP = Vs × Cout 7.5 × I out × RCOMP (9) with VIN Minimum input voltage VS Output voltage Cout Output capacitance L Inductor value, e.g. 3.3 μH or 6.8 μH Iout Maximum output current in the application Make sure that RCOMP < 120 kΩ and CCOMP> 820 pF, independent of the results of the above formulas. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS61087 11 TPS61087 SLVS821C – MAY 2008 – REVISED JULY 2013 www.ti.com Table 3. Recommended Compensation Network Values at High/Low Frequency FREQUENCY L VS 15 V 3.3 μH High (1.2 MHz) 12 V 9V 15 V 6.8 μH Low (650 kHz) 12 V 9V VIN ± 20% RCOMP CCOMP 5V 100 kΩ 820 pF 3.3 V 91 kΩ 1.2 nF 5V 68 kΩ 820 pF 3.3 V 68 kΩ 1.2 nF 5V 39 kΩ 820 pF 3.3 V 39 kΩ 1.2 nF 5V 51 kΩ 1.5 nF 3.3 V 47 kΩ 2.7 nF 5V 33 kΩ 1.5 nF 3.3 V 33 kΩ 2.7 nF 5V 18 kΩ 1.5 nF 3.3 V 18 kΩ 2.7 nF Table 3 gives conservative RCOMP and CCOMP values for certain inductors, input and output voltages providing a very stable system. For a faster response time, a higher RCOMP value can be used to enlarge the bandwidth, as well as a slightly lower value of CCOMP to keep enough phase margin. These adjustments should be performed in parallel with the load transient response monitoring of TPS61087. Input Capacitor Selection For good input voltage filtering low ESR ceramic capacitors are recommended. TPS61087 has an analog input IN. Therefore, a 1 μF bypass is highly recommended as close as possible to the IC from IN to GND. Two 10 μF (or one 22 μF) ceramic input capacitors are sufficient for most of the applications. For better input voltage filtering this value can be increased. See Table 4 and typical applications for input capacitor recommendation. Output Capacitor Selection For best output voltage filtering a low ESR output capacitor like ceramic capcaitor is recommended. Four 10 μF ceramic output capacitors (or two 22 μF) work for most of the applications. Higher capacitor values can be used to improve the load transient response. See Table 4 for the selection of the output capacitor. Table 4. Rectifier Input and Output Capacitor Selection CAPACITOR/SIZE VOLTAGE RATING SUPPLIER COMPONENT CODE CIN 22 μF/1206 16 V Taiyo Yuden EMK316 BJ 226ML IN bypass 1 μF/0603 16 V Taiyo Yuden EMK107 BJ 105KA COUT 10 μF/1206 25 V Taiyo Yuden TMK316 BJ 106KL To calculate the output voltage ripple, the following equation can be used: DVC = VS - VIN I out × VS × f S Cout DVC _ ESR = I L ( peak ) × RC _ ESR (10) with ΔVC Output voltage ripple dependent on output capacitance,output current and switching frequency VS Output voltage VIN Minimum input voltage of boost converter fS Converter switching frequency (typically 1.2 MHz or 650 kHz) Iout Output capacitance ΔVC_ESR Output voltage ripple due to output capacitors ESR (equivalent series resistance) ISWPEAK Inductor peak switch current in the application RC_ESR Output capacitors equivalent series resistance (ESR) 12 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS61087 TPS61087 www.ti.com SLVS821C – MAY 2008 – REVISED JULY 2013 ΔVC_ESR can be neglected in many cases since ceramic capacitors provide low ESR. Frequency Select Pin (FREQ) The frequency select pin FREQ allows to set the switching frequency of the device to 650 kHz (FREQ = low) or 1.2 MHz (FREQ = high). Higher switching frequency improves load transient response but reduces slightly the efficiency. The other benefits of higher switching frequency are a lower output ripple voltage. The use of a 1.2 MHz switching frequency is recommended unless light load efficiency is a major concern. Undervoltage Lockout (UVLO) To avoid mis-operation of the device at low input voltages an undervoltage lockout is included that disables the device, if the input voltage falls below 2.4 V. Thermal Shutdown A thermal shutdown is implemented to prevent damages due to excessive heat and power dissipation. Typically the thermal shutdown happens at a junction temperature of 150°C. When the thermal shutdown is triggered the device stops switching until the junction temperature falls below typically 136°C. Then the device starts switching again. Overvoltage Prevention If overvoltage is detected on the FB pin (typically 3 % above the nominal value of 1.238 V) the part stops switching immediately until the voltage on this pin drops to its nominal value. This prevents overvoltage on the output and secures the circuits connected to the output from excessive overvoltage. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS61087 13 TPS61087 SLVS821C – MAY 2008 – REVISED JULY 2013 www.ti.com APPLICATION INFORMATION L 3.3 µH VIN 5 V ± 20% Cin 2* 10 µF 16 V 8 Cby 1 µF 16 V 3 9 4 5 IN SW EN SW FREQ FB AGND COMP PGND SS VS 15 V/900 mA max. D SL22 6 R1 200 kΩ 7 Cout 4* 10 µF 25 V 2 R2 18 kΩ 1 Rcomp 100 kΩ 10 Css 100 nF TPS61087 Ccomp 820 pF Figure 14. Typical Application, 5 V to 15 V (fS = 1.2 MHz) L 6.8 µH VIN 5 V ± 20% Cin 2* 10 µF 16 V 8 Cby 1 µF 16 V 3 9 4 5 IN SW EN SW FREQ FB AGND COMP PGND SS TPS61087 VS 15 V/900 mA max. D SL22 6 R1 200 kΩ 7 Cout 4* 10 µF 25 V 2 R2 18 kΩ 1 Rcomp 51 kΩ 10 Css 100 nF Ccomp 1.5 nF Figure 15. Typical Application, 5 V to 15 V (fS = 650 kHz) 14 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS61087 TPS61087 www.ti.com SLVS821C – MAY 2008 – REVISED JULY 2013 L 3.3 µH VIN 3.3 V ± 20% Cin 2* 10 µF 16 V 8 Cby 1 µF 16 V 3 9 4 5 IN SW EN SW FREQ FB COMP AGND PGND SS D SL22 6 VS 9 V/950 mA max. R1 110 kΩ 7 Cout 4* 10 µF 25 V 2 R2 18 kΩ 1 Rcomp 39 kΩ 10 Css 100 nF TPS61087 Ccomp 1.2 nF Figure 16. Typical Application, 3.3 V to 9 V (fS = 1.2 MHz) L 6.8 µH VIN 3.3 V ± 20% Cin 2* 10 µF 16 V 8 Cby 1 µF 16 V 3 9 4 5 IN SW EN SW FREQ FB AGND COMP PGND SS TPS61087 VS 9 V/950 mA max. D SL22 6 R1 110 kΩ 7 Cout 4* 10 µF 25 V 2 R2 18 kΩ 1 Rcomp 18 kΩ 10 Css 100 nF Ccomp 2.7 nF Figure 17. Typical Application, 3.3 V to 9 V (fS = 650 kHz) Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS61087 15 TPS61087 SLVS821C – MAY 2008 – REVISED JULY 2013 www.ti.com Riso 10 kW L 6.8 µH VIN 5 V ± 20% Cby 1 µF/16 V 8 Cin 2* 10 µF/ 16 V 3 SW EN 9 FREQ 4 Enable SW IN FB AGND COMP PGND SS 5 VS 15 V/300 mA BC857C D SL22 6 Ciso 1 µF/ 25 V 7 R1 200 kΩ 2 Cout 4*10 µF/ 25 V R2 18 kΩ 1 Rcomp 51 kΩ 10 TPS61087 Css 100 nF Ccomp 1.5 nF Figure 18. Typical Application with External Load Disconnect Switch L 6.8 µH D SL22 VIN 5 V ± 20% 8 Cin 2* 10 µF 16 V Cby 1 µF 16 V 3 9 4 5 IN SW EN SW FREQ FB COMP AGND PGND SS TPS61087 Overvoltage Protection VS 15 V/900 mA max. 6 Dz BZX84C 18V 7 R1 200 kΩ Cout 4* 10 µF 25 V 2 Rlimit 110 Ω 1 R2 18 kΩ Rcomp 51 kΩ 10 Css 100 nF Ccomp 1.5 nF Figure 19. Typical Application, 5 V to 15 V (fS = 1.2 MHz) with Overvoltage Protection 16 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS61087 TPS61087 www.ti.com SLVS821C – MAY 2008 – REVISED JULY 2013 TFT LCD APPLICATION T2 BC850B 3·Vs VGL -7 V/20 mA T1 BC857B R8 6.8 kΩ C13 1 µF/ 35 V C16 470 nF/ 50 V -Vs C14 470 nF/ 25 V D4 BAV99 C15 470 nF/ 50 V D3 BAV99 C18 470 nF/ 50 V R10 13 kΩ 2·Vs C17 470 nF/ 50 V D2 BAV99 D8 BZX84C7V5 Vgh 26.5 V/20 mA C20 1 µF/ 35 V C19 470 nF/ 50 V D9 BZX84C27V L 3.3 µH VIN 5 V ± 20% Cin 2*10 µF/ 16 V Cby 1 µF/ 16 V D SL22 8 IN SW EN SW 3 7 9 R1 200 kΩ Cout 4*10µF/ 25V 2 FREQ FB 4 5 VS 15 V/500 mA 6 R2 18 kΩ 1 AGND COMP PGND SS TPS61087 Rcomp 100 kΩ 10 Css 100 nF Ccomp 820 pF Figure 20. Typical Application 5 V to 15 V (fS = 1.2 MHz) for TFT LCD with External Charge Pumps (VGH, VGL) Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS61087 17 TPS61087 SLVS821C – MAY 2008 – REVISED JULY 2013 www.ti.com WHITE LED APPLICATIONS L 6.8 µH optional VIN 5 V ± 20% Cin 2* 10 µF/ 16 V Cby 1 µF/ 16 V 6 8 3 9 4 5 IN SW EN SW D SL22 Dz BZX84C 18 V VS 500 mA 3S3P wLED LW E67C 7 Cout 4* 10 µF/ 25 V 2 FREQ FB AGND COMP PGND SS Rlimit 110 Ω 1 Rcomp 51 kΩ 10 TPS61087 Css 100 nF Rsense 15 Ω Ccomp 1.5 nF Figure 21. Simple Application (5 V input voltage) (fS = 650 kHz) for wLED Supply (3S3P) (with optional clamping Zener diode) L 6.8 µH optional VIN 5 V ± 20% Cin 2* 10 µF/ 16 V Cby 1 µF/ 16 V 3 9 4 PWM 100 Hz to 500 Hz 6 8 5 IN SW EN SW D SL22 Dz BZX84C 18 V VS 500 mA 3S3P wLED LW E67C 7 Cout 4* 10 µF/ 25 V 2 FREQ FB AGND COMP PGND SS TPS61087 Rlimit 110 Ω 1 Rcomp 51 kΩ 10 Css 100 nF Rsense 15 Ω Ccomp 1.5 nF Figure 22. Simple Application (5 V input voltage) (fS = 650 kHz) for wLED Supply (3S3P) with Adjustable Brightness Control using a PWM Signal on the Enable Pin (with optional clamping Zener diode) 18 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS61087 TPS61087 www.ti.com SLVS821C – MAY 2008 – REVISED JULY 2013 L 6.8 µH optional VIN 5 V ± 20% Cin 2* 10 µF/ 16 V Cby 1 µF/ 16 V 6 8 3 9 4 5 IN SW EN SW D SL22 Dz BZX84C 18 V VS 500 mA 3S3P wLED LW E67C 7 2 FREQ FB AGND COMP PGND SS TPS61087 R1 180 kΩ Rlimit 110 Ω 1 10 Css 100 nF Rcomp 51 kΩ Ccomp 1.5 nF Cout 4* 10 µF/ 25 V Rsense 15 Ω R2 127 kΩ Analog Brightness Control 3.3 V ~ wLED off 0 V ~ lLED = 30 mA (each string) PWM Signal Can be used swinging from 0 V to 3.3 V Figure 23. Simple Application (5 V input voltage) (fS = 650 kHz) for wLED Supply (3S3P) with Adjustable Brightness Control using an Analog Signal on the Feedback Pin (with optional clamping Zener diode) REVISION HISTORY Changes from Original (May 2008) to Revision A • Page Added text to the Detailed Description - following the Block Diagram ................................................................................. 8 Changes from Revision A (June 2008) to Revision B Page • Added DSC package to ORDERING INFORMATION ......................................................................................................... 2 • Deleted Lead temperature from Absolute Maximum Ratings ............................................................................................... 2 • Deleted RθJA from DISSIPATION RATINGS ......................................................................................................................... 2 • Changed fosc to fS in Electrical Characteristics Boost Converter Oscillator Frequency ........................................................ 3 • Changed FREQ = high to FREQ = VIN in Electrical Characteristics Boost Converter Oscillator Frequency ....................... 3 • Changed FREQ = low to FREQ = GND in Electrical Characteristics Boost Converter Oscillator Frequency ...................... 3 • Added DSC package to PIN ASSIGNMENT ........................................................................................................................ 4 • Added Maximum load current vs. Input voltage graph ......................................................................................................... 4 • Added Maximum load current vs. Input voltage graph ......................................................................................................... 4 • Changed f to fS and Frequency to Oscillator Frequency in Figure 11 .................................................................................. 7 • Changed f to fS and Frequency to Oscillator Frequency in Figure 12 .................................................................................. 7 • Changed the text in the Detailed Description. ...................................................................................................................... 8 • Changed "inductor current ripple is below 20%" to " inductor current ripple is below 35%" .............................................. 10 • Added output capacitor calculation ..................................................................................................................................... 13 Changes from Revision B (March 2010) to Revision C • Page Added VIH Test Condition for EN, VIN = 2.5 V to 4.3 V ......................................................................................................... 3 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS61087 19 PACKAGE OPTION ADDENDUM www.ti.com 18-Aug-2013 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish (2) MSL Peak Temp Op Temp (°C) Device Marking (3) (4/5) FX028 ACTIVE SON DRC 10 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 PMOQ TPS61087DRCR ACTIVE SON DRC 10 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 PMOQ TPS61087DRCRG4 ACTIVE SON DRC 10 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 PMOQ TPS61087DRCT ACTIVE SON DRC 10 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 PMOQ TPS61087DRCTG4 ACTIVE SON DRC 10 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 PMOQ TPS61087DSCR ACTIVE WSON DSC 10 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 PMWI TPS61087DSCT ACTIVE WSON DSC 10 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 PMWI (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. Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com 18-Aug-2013 (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. 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. 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. OTHER QUALIFIED VERSIONS OF TPS61087 : • Automotive: TPS61087-Q1 NOTE: Qualified Version Definitions: • Automotive - Q100 devices qualified for high-reliability automotive applications targeting zero defects Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 13-May-2013 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 TPS61087DRCR SON DRC 10 3000 330.0 12.4 3.3 3.3 1.1 8.0 12.0 Q2 TPS61087DRCR SON DRC 10 3000 330.0 12.4 3.3 3.3 1.1 8.0 12.0 Q2 TPS61087DRCT SON DRC 10 250 180.0 12.4 3.3 3.3 1.1 8.0 12.0 Q2 TPS61087DRCT SON DRC 10 250 180.0 12.4 3.3 3.3 1.1 8.0 12.0 Q2 TPS61087DSCR WSON DSC 10 3000 330.0 12.4 3.3 3.3 1.1 8.0 12.0 Q2 TPS61087DSCT WSON DSC 10 250 180.0 12.4 3.3 3.3 1.1 8.0 12.0 Q2 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 13-May-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) TPS61087DRCR SON DRC 10 3000 367.0 367.0 35.0 TPS61087DRCR SON DRC 10 3000 367.0 367.0 35.0 TPS61087DRCT SON DRC 10 250 210.0 185.0 35.0 TPS61087DRCT SON DRC 10 250 210.0 185.0 35.0 TPS61087DSCR WSON DSC 10 3000 367.0 367.0 35.0 TPS61087DSCT WSON DSC 10 250 210.0 185.0 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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