TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com 3 MHz Ultra Small Step Down Converter in 1x1.5 SON Package Check for Samples: TPS62231-Q1, TPS622314-Q1 FEATURES 1 • • • • • • • • • • • • • • • • Qualified for Automotive Applications 3 MHz Switch Frequency Up to 94% Efficiency Output Peak Current up to 500 mA Excellent AC and Transient Load Regulation High PSRR (up to 90 dB) Small External Output Filter Components 1 μH/ 4.7 μF VIN range from 2.05 V to 6 V Optimized Power Save Mode For Low Output Ripple Voltage Forced PWM Mode Operation Typ. 22 μA Quiescent Current 100% Duty Cycle for Lowest Dropout Small 1 × 1.5 × 0.6mm3 SON Package 12 mm2 Minimum Solution Size Supports 0.6 mm Maximum Solution Height Soft Start with typ. 100μs Start Up Time APPLICATIONS • • • • • • L 1/2.2 mH TPS62231 2.05 V - 6 V VIN EN MODE CIN 2.2 mF SW FB GND The TPS6223x-Q1 device family is a high frequency synchronous step down DC-DC converter optimized for battery powered portable applications. It supports up to 500 mA output current and allows the use of tiny and low cost chip inductors and capacitors. With a wide input voltage range of 2.05 V to 6 V the device supports applications powered by Li-Ion batteries with extended voltage range. The minimum input voltage of 2.05 V allows as well the operation from Li-primary or two alkaline batteries. Different fixed output voltage versions are available from 1 V to 3.3 V. The TPS6223x-Q1 series features switch frequency up to 3.8 MHz. At medium to heavy loads, the converter operates in PWM mode and automatically enters Power Save Mode operation at light load currents to maintain high efficiency over the entire load current range. Because of its excellent PSRR and AC load regulation performance, the device is also suitable to replace linear regulators to obtain better power conversion efficiency. The Power Save Mode in TPS6223x-Q1 reduces the quiescent current consumption down to 22 μA during light load operation. It is optimized to achieve very low output voltage ripple even with small external component and features excellent ac load regulation. LDO Replacement Portable Audio, Portable Media Cell Phones Low Power Wireless Low Power DSP Core Supply Digital Cameras VIN DESCRIPTION VOUT 1.8 V For very noise sensitive applications, the device can be forced to PWM Mode operation over the entire load range by pulling the MODE pin high. In the shutdown mode, the current consumption is reduced to less than 1μA. The TPS6223x-Q1 is available in a 1 × 1.5mm2 6 pin SON package. COUT 4.7 mF Total area L1 12mm² V IN C1 C2 GND V OUT 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 © 2011, Texas Instruments Incorporated TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 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) TA –40°C to 105°C (1) OUTPUT VOLTAGE FREQUENCY [MHz] PACKAGE DESIGNATOR TPS62231-Q1 1.8 V 3 TPS622314-Q1 1.5 V 3 PART NUMBER ORDERING PACKAGE MARKING DRY TPS62231TDRYRQ1 31 DRY TPS622314TDRYRQ1 14 For detailed ordering information see the PACKAGE OPTION ADDENDUM at the end of this data sheet. ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) (1) VALUE MIN VI MAX UNIT Voltage at VIN and SW Pin (2) –0.3 7 V Voltage at EN, MODE Pin (2) –0.3 VIN +0.3, ≤7 V –0.3 3.6 V internally limited A Voltage at FB Pin (2) Peak output current ESD rating (3) Human Body Model (HBM) 2 Charged Device Model CDM) 1 Machine Model (MM) 200 Power dissipation kV V Internally limited TJ Maximum operating junction temperature –40 125 °C Tstg Storage temperature range –65 150 °C (1) (2) (3) 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. The human body model is a 100-pF capacitor discharged through a 1.5-kΩ resistor into each pin. The machine model is a 200-pF capacitor discharged directly into each pin. DISSIPATION RATINGS (1) (1) (2) 2 PACKAGE RθJA POWER RATING FOR TA ≤ 25°C DERATING FACTOR ABOVE TA = 25°C 1 × 1.5 SON 234°C/W (2) 420 mW 4.2 mW/°C Maximum power dissipation is a function of TJ(max), θJA and TA. The maximum allowable power dissipation at any allowable ambient temperature is PD = [TJ(max) – TA] /θJA. This thermal data is measured with high-K board (4 layers board according to JESD51-7 JEDEC standard). Copyright © 2011, Texas Instruments Incorporated TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com RECOMMENDED OPERATING CONDITIONS operating ambient temperature TA = –40 to 105°C (unless otherwise noted) (1) MIN Supply voltage VIN (2) 2.05 Effective inductance 2 VOUT ≤ VIN -1 V (3) Recommended minimum supply voltage VOUT ≤ 1.8V Operating junction temperature range, TJ (2) (3) (4) MAX 6 (4) 3 350 mA maximum IOUT (4) 2.5 60 mA maximum output current (4) V μF 4.7 500 mA maximum IOUT UNIT μH 2.2 Effective capacitance (1) NOM 3.6 2.7 V 2.05 –40 125 °C In applications where high power dissipation and/or poor package thermal resistance is present, the maximum ambient temperature may have to be derated. Maximum ambient temperature (TA(max)) is dependent on the maximum operating junction temperature (TJ(max)), the maximum power dissipation of the device in the application (PD(max)), and the junction-to-ambient thermal resistance of the part/package in the application (θJA), as given by the following equation: TA(max) = TJ(max) – (θJA × PD(max)). The minimum required supply voltage for startup is 2.05 V. The part is functional down to the falling UVL (Under Voltage Lockout) threshold. For a voltage difference between minimum VIN and VOUT of ≥ 1 V Typical value applies for TA = 25°C, maximum value applies for TA = 105°C with TJ ≤ 125°C, PCB layout needs to support proper thermal performance. Copyright © 2011, Texas Instruments Incorporated 3 TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com ELECTRICAL CHARACTERISTICS VIN = 3.6V, VOUT = 1.8V, EN = VIN, MODE = GND, TA = –40°C to 105°C (1) typical values are at TA = 25°C (unless otherwise noted), CIN = 2.2μF, L = 2.2μH, COUT = 4.7μF, see parameter measurement information PARAMETER TEST CONDITIONS MIN TYP MAX UNIT SUPPLY VIN Input voltage range IQ (2) Operating quiescent current 2.05 Shutdown current UVLO Undervoltage lockout threshold V 40 μA 22 IOUT = 0mA. PFM mode enabled (Mode = 0) device switching, VIN = 3.6V, VOUT = 1.2V 25 μA 3 mA IOUT = 0 mA. Switching with no load (MODE/DATA = VIN), PWM operation, VOUT = 1.8V, L = 2.2μH ISD 6 IOUT = 0mA. PFM mode enabled (Mode = 0) device not switching EN = GND (3) 0.1 Falling Rising 1 μA 1.8 1.9 V 1.9 2.05 V 0.8 1 V 0.01 0.5 μA 600 850 350 480 690 850 1050 mA 550 840 1220 mA ENABLE, MODE THRESHOLD VIH TH Threshold for detecting high EN, MODE 2.05 V ≤ VIN ≤ 6V , rising edge VIL TH HYS Threshold for detecting low EN, MODE 2.05 V ≤ VIN ≤ 6V , falling edge IIN Input bias Current, EN, MODE EN, MODE = GND or VIN = 3.6V 0.4 0.6 V POWER SWITCH RDS(ON) ILIMF High side MOSFET on-resistance Low Side MOSFET on-resistance Forward current limit MOSFET high-side VIN = 3.6V, TJmax = 105°C; RDS(ON) max value VIN = 3.6V, open loop Forward current limit MOSFET low side TSD mΩ Thermal shutdown Increasing junction temperature 150 °C Thermal shutdown hysteresis Decreasing junction temperature 20 °C 135 ns 40 ns 0.70 V CONTROLLER tONmin Minimum ON time tOFFmin Minimum OFF time VIN 3.6V, VOUT = 1.8V, Mode = high, IOUT = 0 mA OUTPUT VREF Internal Reference Voltage VIN = 3.6V, Mode = GND, device operating in PFM Mode, IOUT = 0mA Output voltage accuracy (4) VOUT tStart ILK_SW (1) (2) (3) (4) (5) 4 VIN = 3.6V, MODE = VIN, IOUT = 0 mA TA = 25°C –2.0% 2.0% TA = –40°C to 105°C –2.5% 2.5% DC output voltage load regulation PWM operation, Mode = VIN = 3.6V, VOUT = 1.8 V DC output voltage line regulation IOUT = 0 mA, Mode = VIN, 2.05V ≤ VIN ≤ 6V Start-up Time Time from active EN to VOUT = 1.8V, VIN = 3.6V, 10Ω load Leakage current into SW pin 0% VIN = VOUT = VSW = 3.6 V, EN = GND (5) 0.001 %/mA 0 %/V μs 100 0.1 0.5 μA In applications where high power dissipation and/or poor package thermal resistance is present, the maximum ambient temperature may have to be derated. Maximum ambient temperature (TA(max)) is dependent on the maximum operating junction temperature (TJ(max)), the maximum power dissipation of the device in the application (PD(max)), and the junction-to-ambient thermal resistance of the part/package in the application (θJA), as given by the following equation: TA(max) = TJ(max) – (θJA × PD(max)). The minimum required supply voltage for startup is 2.05V. The part is functional down to the falling UVL (Under Voltage Lockout) threshold Shutdown current into VIN pin, includes internal leakage VIN = VO + 1.0 V The internal resistor divider network is disconnected from FB pin. Copyright © 2011, Texas Instruments Incorporated TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com DRY PACKAGE (TOP VIEW) MODE 1 6 FB SW 2 5 EN VIN 3 4 GND PIN FUNCTIONS PIN NAME NO I/O DESCRIPTION VIN 3 PWR VIN power supply pin. GND 4 PWR GND supply pin EN 5 IN SW 2 OUT FB 6 IN Feedback Pin for the internal regulation loop. Connect this pin directly to the output capacitor. MODE 1 IN MODE pin = high forces the device to operate in PWM mode. Mode = low enables the Power Save Mode with automatic transition from PFM (Pulse frequency mode) to PWM (pulse width modulation) mode. This is the enable pin of the device. Pulling this pin to low forces the device into shutdown mode. Pulling this pin to high enables the device. This pin must be terminated. This is the switch pin and is connected to the internal MOSFET switches. Connect the inductor to this terminal FUNCTIONAL BLOCK DIAGRAM VIN Bandgap VREF 0.70 V Undervoltage Lockout Limit High Side MODE MODE Current Limit Comparator PMOS Softstart VIN Min. On Time FB EN Min. OFF Time Control Logic Gate Driver Anti Shoot-Through VREF NMOS FB Integrated Feed Back Network SW Limit Low Side Error Comparator Thermal Shutdown Zero/Negative Current Limit Comparator EN GND Copyright © 2011, Texas Instruments Incorporated 5 TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com PARAMETER MEASUREMENT INFORMATION VIN = 2.05 V to 6 V TPS6223X VIN CIN 2.2 mF EN MODE L = 1/2.2 mH VOUT SW FB COUT GND 4.7 mF CIN: Murata GRM155R60J225ME15D 2.2 mF 0402 size COUT: Murata GRM188R60J475ME 4.7 mF 0603 size, VOUT >= 1.8 V COUT: Taiyo Yuden AMK105BJ475MV 4.7 mF 0402 size, VOUT = 1.2 V l: Murata LQM2HPN1R0MJ0 1 mH, LQM2HPN2R2MJ0 2.2 mH, 3 size 2.5x2.0x1.2mm TYPICAL CHARACTERISTICS Table of Graphs FIGURE η Efficiency vs Load current η Efficiency vs Output Current 8, 9, 10, 11 Output voltage vs Output current 12, 13, 14, 15, 16, 17 Switching frequency vs Output current 18, 19, 20, 21, 22, 23, 24, 25, 26, 27 28,29 VO 1, 2, 3, 4, 5, 6, 7 Output voltage peak to peak vs Output current IQ Quiescent current vs Ambient temperature 30 ISD Shutdown current vs Ambient temperature 31 PMOS Static drain-source on-state resistance vs Supply voltage and ambient temperature 32 NMOS Static drain-source on-state resistance vs Supply voltage and ambient temperature 33 Power supply rejection ratio vs Frequency rDS(ON) PSRR Typical operation Line transient response Mode transition PFM / forced PWM AC - load regulation performance Load transient response Start-up 6 34 35, 36, 37 PFM 38 PWM 39 40 41 42, 43 44, 45, 46, 47 48, 49 Spurious Output Noise, 12R Load 50 Spurious Output Noise, 100R Load 51 Copyright © 2011, Texas Instruments Incorporated TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com TYPICAL CHARACTERISTICS (continued) 100 100 VIN = 3.6 V 80 VIN = 2.9 V 70 VIN = 5 V 50 40 30 L = 2.2 mH (LQM2HPN2R2MJ0) COUT = 4.7 mF 10 0 0.1 60 VIN = 5 V 50 40 20 MODE = VIN, VOUT = 2.5 V, 10 L = 2.2 mH (LQM2HPN2R2MJ0) COUT = 4.7 mF 0 1 10 100 IO - Output Current - mA 1 1000 Figure 1. Efficiency PFM/PWM Mode 2.5V Output Voltage 100 100 80 80 VIN = 3.3 V VIN = 2.7 V 60 VIN = 4.2 V VIN = 5 V 20 MODE = GND, VOUT = 1.8 V, 10 L = 2.2 mH (MIPSA25202R2), COUT = 4.7 mF 0 0.1 VIN = 2.3 V VIN = 2.7 V 70 VIN = 3.6 V Efficiency -% Efficiency -% 70 30 1000 VIN = 2.3 V 90 40 10 100 IO - Output Current - mA Figure 2. Efficiency Forced PWM Mode 2.5V Output Voltage 90 50 VIN = 4.2 V 30 MODE = GND, VOUT = 2.5V, 20 VIN = 3.6 V 80 VIN = 4.2 V Efficiency -% Efficiency -% 70 60 VIN = 2.9 V 90 90 VIN = 3.3 V 60 VIN = 3.6 V 50 VIN = 4.2 V 40 VIN = 5 V 30 20 MODE = VIN, VOUT = 1.8 V, 10 L = 2.2 mH (MIPSA25202R2), COUT = 4.7 mF 0 1 10 100 IO - Output Current - mA 1000 Figure 3. Efficiency PFM/PWM MODE 1.8V Output Voltage Copyright © 2011, Texas Instruments Incorporated 1 10 100 IO - Output Current - mA 1000 Figure 4. Efficiency Forced PWM Mode 1.8V Output voltage 7 TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com TYPICAL CHARACTERISTICS (continued) 100 100 90 VIN = 2.3 V 90 40 30 VIN = 3.6 V Efficiency -% Efficiency -% 50 70 VIN = 2.7 V 70 60 VIN = 4.2 V VIN = 5 V VIN = 2.7 V 60 VIN = 3.6 V VIN = 4.2 V 50 VIN = 5 V 40 30 20 MODE = GND, VOUT = 1.2 V, 10 L = 2.2 mH MIPSZ2012 2R2 (2012 size), COUT = 4.7 mF 0 0.1 VIN = 2.3 V 80 80 20 MODE = VIN, VOUT = 1.2 V, 10 L = 2.2 mH MIPSZ2012 2R2 (2012 size), COUT = 4.7 mF 0 1 10 100 IO - Output Current - mA 1000 Figure 5. Efficiency PFM/PWM Mode 1.2V Output voltage 1 10 100 IO - Output Current - mA Figure 6. Efficiency Forced PWM Mode 1.2V Output Voltage 100 90 VIN = 3.6 V 90 85 80 70 MIPSD1R0 L = 1 mH 0805 (2x1.25x1mm3) MIPSZ2012D2R2 L = 2.2 mH 0805 (2x1.25x1mm3) MIPSA25202R2 L = 2.2 mH (2.5x2x1.2mm3) LQM2HPN1R0MJ0 L = 1 mH (2.5x2x1.2mm3) 65 60 55 50 0.1 LQM21PN2R2 L = 2.2 mH 0805 (2x1.25x0.55mm3) COUT = 4.7 mF (0402), VOUT = 1.8 V, VIN = 3.6 V 1000 Figure 7. Comparison Efficiency vs Inductor Value and Size 8 VIN = 4.2 V 60 50 40 30 MODE = GND, CIN = 2.2 mF (0402), 1 10 100 IO - Output Current - mA VIN = 5 V 70 Efficiency - % Efficiency -% 80 75 1000 TPS62233 MODE = GND, VOUT = 3 V, 20 L = 1 mH, COUT = 4.7 mF 10 0 0.1 1 10 100 IO - Output Current - mA 1000 Figure 8. Comparison Efficiency vs IOUT – TPS62233 Copyright © 2011, Texas Instruments Incorporated TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com TYPICAL CHARACTERISTICS (continued) 100 90 VIN = 3.3 V VIN = 3.3 V 90 80 VIN = 3.6 V 80 VIN = 4.2 V Efficiency - % Efficiency - % 70 60 VIN = 3.6 V VIN = 4.2 V 70 60 50 50 40 40 VOUT = 1.2 V PFM, MODE = GND 30 0.1 1 10 100 IO - Output Current - mA TPS62236 VOUT = 1.85 V PFM 30 0.1 1000 Figure 9. Comparison Efficiency vs IOUT – TPS62235 1000 2.575 VIN = 3.3 V MODE = VIN, VOUT = 2.5 V, 2.55 80 VO - Output Voltage (DC) - V VIN = 3.6 V VIN = 4.2 V 70 Efficiency - % 10 100 IO - Output Current - mA Figure 10. Comparison Efficiency vs IOUT – TPS62236 90 60 50 40 30 0.1 1 10 100 IO - Output Current - mA 1000 Figure 11. Comparison Efficiency vs IOUT – TPS622311 Copyright © 2011, Texas Instruments Incorporated VIN = 3.3 V VIN = 3.6 V 2.5 VIN = 4.2 V 2.475 VIN = 5 V 2.45 TPS622311 VOUT = 1.1 V PFM 1 2.525 L = 1 mH, COUT = 4.7 mF, TA = 25°C 2.425 0.1 1 10 100 IO - Output Current - mA 1000 Figure 12. 2.5V Output Voltage Accuracy forced PWM Mode 9 TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com TYPICAL CHARACTERISTICS (continued) 2.575 VIN = 4.2 V 2.525 2.5 VIN = 5 V VIN = 3.3 V VIN = 3.6 V 2.475 MODE = GND, VOUT = 1.8 V, 1.836 VO - Output Voltage (DC) - V L = 1 mH, COUT = 4.7 mF, TA = 25°C 2.55 VO - Output Voltage (DC) - V 1.854 MODE = GND, VOUT = 2.5 V, 2.425 0.1 1 10 100 IO - Output Current - mA VIN = 3.6 V VIN = 3.3 V 1.8 VIN = 4.2 V 1.782 1.746 0.01 1000 Figure 13. 2.5V Output Voltage Accuracy PFM/PWM Mode VIN = 5 V 1.818 L = 1 mH, COUT = 4.7 mF, TA = 25°C 1.224 VIN = 3.3 V VIN = 3.6 V VIN = 5 V VIN = 4.2 V 1.212 L = 2.2 mH, COUT = 4.7 mF, TA = 25°C VIN = 3.3 V VIN = 3.6 V 1.2 VIN = 4.2 V 1.188 VIN = 5 V 1.176 1.764 1.746 0.1 1000 MODE = VIN, VOUT = 1.2 V, 1.8 1.782 1 10 100 IO - Output Current - mA 1.236 MODE = VIN, VOUT = 1.8 V, VO - Output Voltage (DC) - V 1.836 0.1 Figure 14. 1.8V Output Voltage Accuracy PFM/PWM Mode 1.854 VO - Output Voltage (DC) - V 1.818 1.764 2.45 1 10 100 IO - Output Current - mA 1000 Figure 15. 1.8V Output Voltage Accuracy Forced PWM MODE 10 L = 2.2 mH, COUT = 4.7 mF, TA = 25°C 1.164 0.1 1 10 100 IO - Output Current - mA 1000 Figure 16. 1.2V Output Voltage Accuracy Forced PWM MODE Copyright © 2011, Texas Instruments Incorporated TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com TYPICAL CHARACTERISTICS (continued) 1.236 4000 MODE = GND, VOUT = 1.2 V, VIN = 5 V 3500 L = 2.2 mH, COUT = 4.7 mF, TA = 25°C VIN = 4.2 V 3000 VIN = 3.3 V 1.212 f - Frequency - kHz VO - Output Voltage (DC) - V 1.224 VIN = 3.6 V 1.2 VIN = 4.2 V 1.188 VIN = 5 V VIN = 3.6 V VIN = 3.3 V 2500 2000 1500 1000 1.176 0 0.1 1 10 IO - Output Current - mA 100 1000 Figure 17. 1.2V Output Voltage Accuracy PFM/PWM MODE 4000 0 VIN = 4.2 V VIN = 3.6 V 3500 3000 VIN = 3.3 V f - Frequency - kHz f - Frequency - kHz 3000 2500 2000 1500 500 0 0 100 500 VIN = 5 V VIN = 3.6 V VIN = 2.3 V 200 300 400 IO - Output Current - mA 4000 VIN = 4.2 V 1000 100 Figure 18. Switching Frequency vs Output Current, 1.8V Output Voltage MODE = GND VIN = 5 V 3500 L = 2.2 mH, COUT = 4.7 mF, TA = 25°C VIN = 2.3 V 500 1.164 0.01 MODE = GND, VOUT = 1.8 V, VIN = 2.7 V VIN = 2.7 V MODE = GND, VOUT = 1.8 V, 2000 1500 VIN = 2.7 V VIN = 2.3 V 500 500 Figure 19. Switching Frequency vs Output Current, 1.8V Output Voltage MODE = GND Copyright © 2011, Texas Instruments Incorporated 2500 1000 L = 1 mH, COUT = 4.7 mF, TA = 25°C 200 300 400 IO - Output Current - mA VIN = 3.3 V 0 0 100 MODE = VIN, VOUT = 1.8 V, L = 2.2 mH, COUT = 4.7 mF, TA = 25°C 200 300 400 IO - Output Current - mA 500 Figure 20. Switching Frequency vs Output Current, 1.8V Output Voltage MODE = VIN 11 TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com TYPICAL CHARACTERISTICS (continued) 4000 4000 3500 VIN = 5 V L = 2.2 mH, C = 4.7 mF, VIN = 3.3 V OUT TA = 25°C 3000 VIN = 3.6 V 2000 VIN = 3.3 V 1500 2500 2000 1500 1000 1000 VIN = 3 V 500 0 0 100 VIN = 3 V 500 0 200 300 400 IO - Output Current - mA 500 Figure 21. Switching Frequency vs Output Current, 2.5V Output Voltage MODE = GND 0 100 VIN = 5 V VIN = 4.2 V 3000 2500 VIN = 4.2 V VIN = 3.3 V 2500 VIN = 3.6 V VIN = 3.6 V f - Frequency - kHz f - Frequency - kHz 500 3000 VIN = 5 V VIN = 2.7 V 2000 1500 VIN = 2.3 V 1000 VIN = 2 V 500 0 0 200 300 400 IO - Output Current - mA Figure 22. Switching Frequency vs Output Current, 2.5V Output Voltage MODE = VIN 3500 MODE = GND, VOUT = 1.2 V, L = 2.2 mH, COUT = 4.7 mF, TA = 25°C VIN = 3.3 V 2000 1500 VIN = 2.3 V VIN = 2 V 1000 200 300 400 IO - Output Current - mA 500 VIN = 2.7 V MODE = VIN, VOUT = 1.2 V, 500 L = 2.2 mH, COUT = 4.7 mF, TA = 25°C 0 100 Figure 23. Switching Frequency vs Output Current, 1.2V Output Voltage MODE = GND 12 MODE = VIN, VOUT = 2.5 V, VIN = 4.2 V VIN = 3.6 V f - Frequency - kHz 2500 VIN = 5 V 3500 L = 2.2 mH, VIN = 4.2 V COUT = 4.7 mF, TA = 25°C 3000 f - Frequency - kHz MODE = GND, VOUT = 2.5 V, 0 100 200 300 400 IO - Output Current - mA 500 Figure 24. Switching Frequency vs Output Current, 1.2V Output Voltage MODE = VIN Copyright © 2011, Texas Instruments Incorporated TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com TYPICAL CHARACTERISTICS (continued) 3000 2500 VIN = 5 V VIN = 4.2 V 1500 VIN = 2.3 V VIN = 2.7 V VIN = 3.3 V 1000 VIN = 4.2 V f - Frequency - KHz f - Frequency - KHz 2000 TPS62235 MODE = GND, VOUT = 1.2 V, 500 1500 VIN = 3.3 V VIN = 3.6 V 1000 500 VIN = 2.3 V 0 0 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 IO - Output Current - A Figure 25. Switching Frequency vs Output Current, 1.2V Output Voltage MODE = PFM – TPS62235 1500 VIN = 2.7 V VIN = 3.3 V VIN = 2.3 V 1000 TPS622311 MODE = GND, VOUT = 1.1 V, 500 L = 2.2 mH, COUT = 4.7 mF 0 0 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 IO - Output Current - A Figure 27. Switching Frequency vs Output Current, 1.1V Output Voltage MODE = PFM – TPS622311 Copyright © 2011, Texas Instruments Incorporated VO(PP) - Peak-to-Peak Output Voltage - mV 2500 TPS62230 45 VO = 2.5 V, L = 2.2 mH 2012, 40 (MIPSZ2012), CO = 4.7 mF 0402 35 VIN = 4.2 V L = 2.2 mH, COUT = 4.7 mF Figure 26. Switching Frequency vs Output Current, 1.85V Output Voltage MODE = PFM –TPS62236 50 2000 TPS62236 MODE = GND, VOUT = 1.85 V, 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 IO - Output Current - A 3000 VIN = 5 V f - Frequency - KHz 2000 VIN = 2.7 V L = 2.2 mH, COUT = 4.7 mF 0 0 VIN = 5 V 2500 VIN = 3.6 V 30 VI = 3.3 V 25 VI = 3.6 V 20 15 10 5 VI = 4.2 V 0 0 50 100 150 200 250 300 350 400 450 500 IO - Output Current - mA Figure 28. Output Voltage, Peak-to-Peak vs Output Current - TPS62230 13 TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com TYPICAL CHARACTERISTICS (continued) 35 TPS62230 VO = 1.8 V, TA = 85°C 25 L = 2.2 mH 2012, (MIPSZ2012), CO = 4.7 mF 0402 20 VI = 3.3 V VI = 3.6 V 15 10 VI = 4.2 V 5 0 50 100 150 200 250 300 350 400 450 500 IO - Output Current - mA ISD - Shutdown Current - mA 0.16 0.14 0.12 0.1 TA = 60°C TA = 25°C TA = -40°C 0.06 0.04 0.02 0 2 2.5 3 3.5 4 4.5 5 VIN - Input Voltage - V 5.5 6 Figure 31. Shutdown Current ISD vs Ambient Temperature TA rDS(ON) - Static Drain-Source On-State Resistance - W TA = 85°C 0.08 TA = -40°C 2 2.5 3 3.5 4 4.5 5 VIN - Input Voltage - V 5.5 6 Figure 30. Quiescent Current IQ vs Ambient Temperature TA 0.2 14 20 15 Figure 29. Output Voltage, Peak-to-Peak vs Output Current – TPS62231-Q1 0.18 TA = 25°C 25 10 0 TA = 60°C 30 IQ - Quiescent Current - mA VO(PP) - Peak-to-Peak Output Voltage - mV 30 2 PMOS 1.8 TA = 85°C TA = 60°C 1.6 1.4 TA = 25°C 1.2 TA = -40°C 1 0.8 0.6 0.4 0.2 0 2 2.5 3 3.5 4 4.5 5 VIN - Input Voltage - V 5.5 6 Figure 32. PMOS RDS(ON) vs Supply Voltage VIN and Ambient Temperature TA Copyright © 2011, Texas Instruments Incorporated TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com 100 0.7 NMOS PSRR - Power Supply Rejection Ratio - dB rDS(ON) - Static Drain-Source On-State Resistance - W TYPICAL CHARACTERISTICS (continued) TA = 85°C 0.6 TA = 60°C 0.5 TA = 25°C TA = -40°C 0.4 0.3 0.2 0.1 IOUT = 50 mA, MODE = 0, forced PWM 90 80 70 60 IOUT = 50 mA, MODE = 1, PFM/PWM IOUT = 150 mA, PWM Mode 50 40 30 VIN = 3.6 V, VOUT = 1.8 V, 20 CIN = 2.2 mF, COUT = 4.7 mF, 10 L = 2.2 mH 0 2 2.5 3 3.5 4 4.5 5 VIN - Input Voltage - V 5.5 6 0 10 100 Figure 33. NMOS RDS(ON) vs Supply Voltage VIN and Ambient Temperature TA SW 2 V/div 1k 10k f - Frequency - kHz 100k 1M Figure 34. TPS62231 1.8V PSRR VIN = 3.6 V VIN = 3.6V COUT = 4.7 mF L = 1 mH VOUT = 2.5V 20 mV/Div VOUT = 2.5V 20 mV/div COUT = 4.7 mF SW 2 V/div MODE = GND IOUT = 10 mA L = 2.2 mH MODE = GND IOUT = 10 mA IL 200 mA/Div t - Time - 1 ms/div Figure 35. PFM Mode Operation IOUT = 10mA Copyright © 2011, Texas Instruments Incorporated IL 200 mA/div t - Time - 1 ms/div Figure 36. PFM Mode Operation IOUT = 10mA 15 TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com TYPICAL CHARACTERISTICS (continued) VOUT = 2.5 V 20 mV/div MODE = VIN IOUT = 10 mA VIN = 3.6 V COUT = 4.7 mF L = 1 mH VIN = 3.6 V to 4.2 V 200 mV/div SW 2 V/div IL 200 mA/div COUT = 4.7 mF VOUT = 1.8 V 20 mV/div t - Time - 500 ns/div Figure 37. Forced PWM Mode Operation IOUT = 10mA L = 2.2 mH MODE = GND IOUT = 50 mA t - Time - 10 ms/div Figure 38. Line Transient Response PFM Mode MODE: 0 V to 3.6 V 2 V/div PFM Mode Operation VIN = 3.6 V to 4.2 V 200 mV/div Forced PWM Mode Operation VSW 2 V/div VIN = 3.6 V, ICOIL 200 mA/div VOUT = 1.8 V 20 mV/div L = 1 mH IOUT = 10 mA COUT = 4.7 mF L = 2.2 mH MODE = VIN IOUT = 50 mA t - Time - 100 ms/div Figure 39. Line Transient Response PWM Mode 16 COUT = 4.7 mF VOUT = 1.8 V 20 mV/div t - Time - 1 ms/div Figure 40. Mode Transition PFM / Forced PWM Mode Copyright © 2011, Texas Instruments Incorporated TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com TYPICAL CHARACTERISTICS (continued) VIN = 3.6 V VOUT = 2.5 V 50 mV/div COUT = 4.7 mF VOUT = 2.5 V 50 mV/div L = 2.2 mH MODE = GND VIN = 3.6 V IOUT = 5 mA to 200 mA sinusoidal 100 mA/div IOUT = 5mA to 200mA sinusoidal 100mA/Div IL 200 mA/div COUT = 4.7 mF L = 2.2 mH MODE = VIN IL 200 mA/div t - Time - 5 ms/div t - Time - 5 ms/div Figure 41. AC – Load Regulation Performance 2.5V VOUT PFM Mode Figure 42. AC – Load Regulation Performance 2.5V VOUT PWM Mode VIN = 3.6 V COUT = 4.7 mF VOUT = 1.8 V 50 mV/div L = 2.2 mH MODE = GND IOUT = 5 mA to 150 mA, 50 kHz sinusoidal 100 mA/div VOUT = 2.5 V 50 mV/div VIN = 3.6 V COUT = 4.7 mF IOUT = 5 mA to 200 mA 100 mA/div L = 1 mH MODE = GND IL 200 mA/div IL 200 mA/div t - Time - 4 ms/div Figure 43. AC – Load Regulation Performance 1.8V VOUT PFM Mode Copyright © 2011, Texas Instruments Incorporated t - Time - 5 ms/div Figure 44. Load Transient Response 5mA to 200mA PFM to PWM Mode, VOUT 2.5V 17 TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com TYPICAL CHARACTERISTICS (continued) VIN = 3.6 V VOUT = 2.5 V 50 mV/div COUT = 4.7 mF VOUT = 1.8 V 50 mV/div L = 2.2 mH MODE = GND VIN = 3.6 V IOUT = 5 mA to 200 mA 100 mA/div COUT = 4.7 mF L = 1 mH MODE = VIN IL 200 mA/div I OUT = 5 mA to 150 mA 100 mA/div IL 200 mA/div t - Time - 10 ms/div t - Time - 5 ms/div Figure 45. Load Transient Response 5mA to 200mA, Forced PWM Mode, VOUT 2.5V Figure 46. Load Transient Response 5mA to 150mA, PFM to PWM Mode, VOUT 1.8V VIN = 3.6 V COUT = 4.7 mF VOUT = 1.8 V 50 mV/div L = 2.2 mH MODE = VIN EN 2 V/div SW 2 V/div VIN = 3.6 V IOUT = 5 mA to 150 mA 100 mA/div IL 200 mA/div COUT = 4.7 mF L = 1 mH MODE = GND Load = 20 R IIN 50 mA/div t - Time - 10 ms/div Figure 47. Load Transient Response 5mA to 150mA, Forced PWM Mode, VOUT 1.8V 18 VOUT = 0 V to 2.5 V 1 V/div t - Time - 20 ms/div Figure 48. Start Up into 20Ω Load, VOUT 2.5V Copyright © 2011, Texas Instruments Incorporated TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com TYPICAL CHARACTERISTICS (continued) 1m EN 2 V/div 900m TPS62231 MODE = GND, VOUT = 1.8 V, Ref Lvl = 1mV RBW 30kHz VBW 30kHz SWT ´115ms RLOAD = 12R 800m 700m VOUT = 1.8 V 1 V/div VOUT Pre Bias = 1V VIN = 2.7V(green) Noise 600m SW 5 V/div IL 200 mA/div L = 2.2 mH, (MIPSZ2012 2R2, Size 2012) COUT = 4.7 mF (Size 0402) 500m VIN = 3.6 V 400m COUT = 4.7 mF 300m L = 2.2 mH MODE = GND IOUT = 0 mA 200m VIN = 3V(red) VIN = 3.6V(blue) VIN = 4.2V(yellow) 100m 10n Time Base - 20 ms/div Start 0 Hz Figure 49. Startup in 1V Pre-biased Output 800m Stop 40 MHz Figure 50. Spurious Output Noise, 12R Load, TPS62231-Q1 1m 900m 4 MHz f - Frequency TPS62231 MODE = GND, VOUT = 1.8 V, Ref Lvl = 1mV RBW 30kHz VBW 30kHz SWT 28ms RLOAD = 100R L = 2.2 mH, (MIPSZ2012 2R2, Size 2012) COUT = 4.7 mF (Size 0402) 700m Noise 600m VIN = 4.2V(yellow) 500m VIN = 3.6V(blue) 400m VIN = 3V(red) 300m 200m VIN = 2.7V(green) 100m 10n Stop 1 MHz 10 MHz f - Frequency Figure 51. Spurious Output Noise, 100R Load, TPS62231-Q1 Start 0 Hz Copyright © 2011, Texas Instruments Incorporated 19 TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com DETAILED DESCRIPTION The TPS6223x-Q1 synchronous step down converter family includes a unique hysteretic PWM controller scheme which enables switch frequencies over 3MHz, excellent transient and AC load regulation as well as operation with cost competitive external components. The controller topology supports forced PWM Mode as well as Power Save Mode operation. Power Save Mode operation reduces the quiescent current consumption down to 22 μA and ensures high conversion efficiency at light loads by skipping switch pulses. In forced PWM Mode, the device operates on a quasi fixed frequency, avoids pulse skipping, and allows filtering of the switch noise by external filter components. The TPS6223x-Q1 devices offer fixed output voltage options featuring smallest solution size by using only three external components. The internal switch current limit of typical 850 mA supports output currents of up to 500 mA, depending on the operating condition. A significant advantage of TPS6223x-Q1 compared to other hysteretic PWM controller topologies is its excellent DC and AC load regulation capability in combination with low output voltage ripple over the entire load range which makes this part well suited for audio and RF applications. OPERATION Once the output voltage falls below the threshold of the error comparator, a switch pulse is initiated, and the high side switch is turned on. It remains turned on until a minimum on time of tONmin expires and the output voltage trips the threshold of the error comparator or the inductor current reaches the high side switch current limit. Once the high side switch turns off, the low side switch rectifier is turned on and the inductor current ramps down until the high side switch turns on again or the inductor current reaches zero. In forced PWM Mode operation, negative inductor current is allowed to enable continuous conduction mode even at no load condition. POWER SAVE MODE Connecting the MODE pin to GND enables the automatic PWM and power-save mode operation. The converter operates in quasi fixed frequency PWM mode at moderate to heavy loads and in the PFM (Pulse Frequency Modulation) mode during light loads, which maintains high efficiency over a wide load current range. In PFM Mode, the device starts to skip switch pulses and generates only single pulses with an on time of tONmin. The PFM Mode frequency depends on the load current and the external inductor and output capacitor values. The PFM Mode of TPS6223x-Q1 is optimized for low output voltage ripple if small external components are used. Even at low output currents, the PFM frequency is above the audible noise spectrum and makes this operation mode suitable for audio applications. The on time tONmin can be estimated to: V t ONmin = OUT ´ 260 ns VIN (1) Therefore, the peak inductor current in PFM mode is approximately: (V - VOUT ) ´ t ONmin ILPFMpeak = IN L (2) The transition from PFM into PWM mode and vice versa can be estimated to: IOUT_PFM/PWM = 0.5 x ILPFMpeak (3) With tON: High side switch on time [ns] VIN: Input voltage [V] VOUT: Output voltage [V] L : Inductance [μH] ILPFMpeak : PFM inductor peak current [mA] IOUT_PFM/PWM : Output current for PFM to PWM mode transition and vice versa [mA] 20 Copyright © 2011, Texas Instruments Incorporated TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com FORCED PWM MODE Pulling the MODE pin high forces the converter to operate in a continuous conduction PWM mode even at light load currents. The advantage is that the converter operates with a quasi fixed frequency that allows simple filtering of the switching frequency for noise-sensitive applications. In this mode, the efficiency is lower compared to the power-save mode during light loads. For additional flexibility, it is possible to switch from power-save mode to forced PWM mode during operation. This allows efficient power management by adjusting the operation of the converter to the specific system requirements. 100% DUTY CYCLE LOW DROPOUT OPERATION The device starts to enter 100% duty cycle mode once the input voltage comes close to the nominal output voltage. In order to maintain the output voltage, the High Side switch is turned on 100% for one or more cycles. With further decreasing VIN the High Side MOSFET switch is turned on completely. In this case the converter offers a low input-to-output voltage difference. This is particularly useful in battery-powered applications to achieve longest operation time by taking full advantage of the whole battery voltage range. The minimum input voltage to maintain regulation depends on the load current and output voltage, and can be calculated as: VINmin = VOUT max + IOUT max ´ RDS(on)max+ RL ( ) (4) With: IOUTmax = maximum output current plus inductor ripple current RDS(on)max = maximum P-channel switch RDSon. RL = DC resistance of the inductor VOUTmax = nominal output voltage plus maximum output voltage tolerance UNDER VOLTAGE LOCKOUT The under voltage lockout circuit prevents the device from misoperation at low input voltages. It prevents the converter from turning on the switch or rectifier MOSFET under undefined conditions. The TPS6223x-Q1 devices have a UVLO threshold set to 1.8V (typical). Fully functional operation is permitted for input voltage down to the falling UVLO threshold level. The converter starts operation again once the input voltage trips the rising UVLO threshold level. SOFT START The TPS6223x-Q1 has an internal soft-start circuit that controls the ramp up of the output voltage and limits the inrush current during start-up. This limits input voltage drops when a battery or a high-impedance power source is connected to the input of the converter. The soft-start system generates a monotonic ramp up of the output voltage and reaches the nominal output voltage typically 100μs after EN pin was pulled high. Should the output voltage not have reached its target value by this time, such as in the case of heavy load, the converter then operates in a current limit mode set by its switch current limits. TPS6223x-Q1 is able to start into a pre-biased output capacitor. The converter starts with the applied bias voltage and ramps the output voltage to its nominal value. ENABLE / SHUTDOWN The device starts operation when EN is set high and starts up with the soft start as previously described. For proper operation, the EN pin must be terminated and must not be left floating. Pulling the EN pin low forces the device into shutdown, with a shutdown quiescent current of typically 0.1 μA. In this mode, the P and N-channel MOSFETs are turned off, the internal resistor feedback divider is disconnected, and the entire internal-control circuitry is switched off. Copyright © 2011, Texas Instruments Incorporated 21 TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com The EN input can be used to control power sequencing in a system with various DC/DC converters. The EN pin can be connected to the output of another converter, to drive the EN pin high and getting a sequencing of supply rails. SHORT-CIRCUIT PROTECTION The TPS6223x-Q1 integrates a High Side and Low Side MOSFET current limit to protect the device against heavy load or short circuit. The current in the switches is monitored by current limit comparators. When the current in the P-channel MOSFET reaches its current limit, the P-channel MOSFET is turned off and the N-channel MOSFET is turned on to ramp down the current in the inductor. The High Side MOSFET switch can only turn on again, once the current in the Low Side MOSFET switch has decreased below the threshold of its current limit comparator. THERMAL SHUTDOWN As soon as the junction temperature, TJ, exceeds 150°C (typical) the device goes into thermal shutdown. In this mode, the High Side and Low Side MOSFETs are turned-off. The device continues its operation when the junction temperature falls below the thermal shutdown hysteresis. 22 Copyright © 2011, Texas Instruments Incorporated TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com APPLICATION INFORMATION VIN 2.05 V - 6 V L 1/2.2 mH TPS62231 VIN EN CIN 2.2 mF MODE SW FB GND VOUT 1.8 V COUT 4.7 mF Figure 52. TPS62231 1.8V Output OUTPUT FILTER DESIGN (INDUCTOR AND OUTPUT CAPACITOR) The TPS6223x-Q1 is optimized to operate with effective inductance values in the range of 0.7 μH to 4.3 μH and with effective output capacitance in the range of 2 μF to 15 μF. The internal compensation is optimized to operate with an output filter of L = 1 μH/2.2 μH and COUT = 4.7 μF. Larger or smaller inductor/capacitor values can be used to optimize the performance of the device for specific operation conditions. For more details, see the CHECKING LOOP STABILITY section. INDUCTOR SELECTION The inductor value affects its peak-to-peak ripple current, the PWM-to-PFM transition point, the output voltage ripple and the efficiency. The selected inductor has to be rated for its dc resistance and saturation current. The inductor ripple current (ΔIL) decreases with higher inductance and increases with higher VI N or VO UT. Equation 5 calculates the maximum inductor current under static load conditions. The saturation current of the inductor should be rated higher than the maximum inductor current as calculated with Equation 6. This is recommended because during heavy load transient the inductor current will rise above the calculated value. Vout 1Vin D IL = Vout ´ L ´ ¦ (5) ILmax = Ioutmax + DIL 2 (6) With: f = Switching Frequency L = Inductor Value ΔIL= Peak to Peak inductor ripple current ILmax = Maximum Inductor current In high-frequency converter applications, the efficiency is essentially affected by the inductor AC resistance (i.e., quality factor) and to a smaller extent by the inductor DCR value. To achieve high efficiency operation, care should be taken in selecting inductors featuring a quality factor above 25 at the switching frequency. Increasing the inductor value produces lower RMS currents, but degrades transient response. For a given physical inductor size, increased inductance usually results in an inductor with lower saturation current. The total losses of the coil consist of both the losses in the DC resistance, R(DC), and the following frequency-dependent components: • The losses in the core material (magnetic hysteresis loss, especially at high switching frequencies) • Additional losses in the conductor from the skin effect (current displacement at high frequencies) • Magnetic field losses of the neighboring windings (proximity effect) • Radiation losses The following inductor series from different suppliers have been used with the TPS6223x-Q1 converters. Copyright © 2011, Texas Instruments Incorporated 23 TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com Table 1. List of inductors INDUCTANCE [μH] DIMENSIONS [mm3] INDUCTOR TYPE SUPPLIER 1.0/2.2 2.5 × 2.0 × 1.2 LQM2HPN1R0MJ0 Murata 2.2 2.0 × 1.2 × 0.55 LQM21PN2R2 Murata 1.0/2.2 2.0 × 1.2 × 1.0 MIPSZ2012 FDK 1.0/2.2 2.0 × 2.5 × 1.2 MIPSA2520 FDK 1.0/2.2 2.0 × 1.2 × 1.0 KSLI2012 series Hitachi Metal OUTPUT CAPACITOR SELECTION The unique hysteretic PWM control scheme of the TPS62230 allows the use of tiny ceramic capacitors. Ceramic capacitors with low ESR values have the lowest output voltage ripple and are recommended. The output capacitor requires either an X7R or X5R dielectric. Y5V and Z5U dielectric capacitors, aside from their wide variation in capacitance over temperature, become resistive at high frequencies. At light load currents the converter operate in Power Save Mode and the output voltage ripple is dependent on the output capacitor value and the PFM peak inductor current. Higher output capacitor values minimize the voltage ripple in PFM Mode and tighten DC output accuracy in PFM Mode. INPUT CAPACITOR SELECTION Because of the nature of the buck converter having a pulsating input current, a low ESR input capacitor is required for best input voltage filtering and minimizing the interference with other circuits caused by high input voltage spikes. For most applications a 2.2 μF to 4.7 μF ceramic capacitor is recommended. The input capacitor can be increased without any limit for better input voltage filtering. Because ceramic capacitor loses up to 80% of its initial capacitance at 5 V, it is recommended to use 4.7 μF input capacitors for input voltages > 4.5 V. Take care when using only small ceramic input capacitors. When a ceramic capacitor is used at the input and the power is being supplied through long wires, such as from a wall adapter, a load step at the output or VIN step on the input can induce ringing at the VIN pin. This ringing can couple to the output and be mistaken as loop instability or could even damage the part by exceeding the maximum ratings. Table 2 shows a list of tested input/output capacitors. Table 2. List of Capacitor CAPACITANCE [μF] SIZE CAPACITOR TYPE SUPPLIER 2.2 0402 GRM155R60J225 Murata 4.7 0402 AMK105BJ475MV Taiyo Yuden 4.7 0402 GRM155R60J475 Murata 4.7 0402 CL05A475MQ5NRNC Samsung 4.7 0603 GRM188R60J475 Murata CHECKING LOOP STABILITY The first step of circuit and stability evaluation is to look from a steady-state perspective at the following signals: • Switching node, SW • Inductor current, IL • Output ripple voltage, VOUT(AC) These are the basic signals that need to be measured when evaluating a switching converter. When the switching waveform shows large duty cycle jitter or the output voltage or inductor current shows oscillations, the regulation loop may be unstable. This is often a result of board layout and/or L-C combination. As a next step in the evaluation of the regulation loop, the load transient response is tested. The time between 24 Copyright © 2011, Texas Instruments Incorporated TPS62231-Q1 TPS622314-Q1 SLVSB63 – DECEMBER 2011 www.ti.com the application of the load transient and the turn on of the P-channel MOSFET, the output capacitor must supply all of the current required by the load. VOUT immediately shifts by an amount equal to ΔI(LOAD) x ESR, where ESR is the effective series resistance of COUT. ΔI(LOAD) begins to charge or discharge CO generating a feedback error signal used by the regulator to return VOUT to its steady-state value. The results are most easily interpreted when the device operates in PWM mode. During this recovery time, VOUT can be monitored for settling time, overshoot or ringing that helps judge the converter’s stability. Without any ringing, the loop has usually more than 45° of phase margin. Because the damping factor of the circuitry is directly related to several resistive parameters (e.g., MOSFET rDS(on)) that are temperature dependant, the loop stability analysis has to be done over the input voltage range, load current range, and temperature range. LAYOUT CONSIDERATIONS As for all switching power supplies, the layout is an important step in the design. Proper function of the device demands careful attention to PCB layout. 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, impedance ground path. Therefore, use wide and short traces for the main current paths. The input capacitor should be placed as close as possible to the IC pins as well as the inductor and output capacitor. Use a common Power GND node and a different node for the Signal GND to minimize the effects of ground noise. Keep the common path to the GND PIN, which returns the small signal components and the high current of the output capacitors as short as possible to avoid ground noise. The FB line should be connected to the output capacitor and routed away from noisy components and traces (e.g. SW line). L1 V IN Total area is less than 12mm² C1 C2 GND V OUT Figure 53. Recommended PCB Layout for TPS6223x-Q1 Copyright © 2011, Texas Instruments Incorporated 25 PACKAGE OPTION ADDENDUM www.ti.com 26-Dec-2011 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Qty Eco Plan (2) Lead/ Ball Finish MSL Peak Temp (3) TPS622314TDRYRQ1 ACTIVE SON DRY 6 5000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR TPS62231TDRYRQ1 ACTIVE SON DRY 6 5000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR Samples (Requires Login) (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. 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. 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OTHER QUALIFIED VERSIONS OF TPS62231-Q1, TPS622314-Q1 : • Catalog: TPS62231, TPS622314 NOTE: Qualified Version Definitions: Addendum-Page 1 PACKAGE OPTION ADDENDUM www.ti.com 26-Dec-2011 • Catalog - TI's standard catalog product Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 26-Dec-2011 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 TPS622314TDRYRQ1 SON DRY 6 5000 179.0 8.4 1.2 1.65 0.7 4.0 8.0 Q1 TPS62231TDRYRQ1 SON DRY 6 5000 179.0 8.4 1.2 1.65 0.7 4.0 8.0 Q1 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 26-Dec-2011 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) TPS622314TDRYRQ1 SON DRY 6 5000 195.0 200.0 45.0 TPS62231TDRYRQ1 SON DRY 6 5000 195.0 200.0 45.0 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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