TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 2 MHz 650 mA Step Down Converter for RF Power Amplifiers in Tiny 8-pin WCSP Package FEATURES 1 • • • • • • • • • • • DESCRIPTION High-Efficiency Step-Down Converter Output Current up to 650 mA VIN Range From 2.5 to 6.0 V 2.0-MHz Fixed-Frequency Operation Dynamic Voltage Control With External Reference (1.3 V to 3.09 V) Fast Output-Voltage Settling (1.3 V to 3.09 V in 20 µs) Soft Start Overload Protection Undervoltage Lockout Thermal Protection 8-Pin WCSP Package The TPS62700 device is a high-efficiency synchronous step-down DC-DC converter optimized for RF power-amplifier (PA) applications. It provides up to 650 mA of output current from a single Li-Ion cell. The device converts input voltages from 2.5 to 6.0 V down to an output voltage set by an external analog reference voltage applied to the pin VCON. The output voltage follows the external reference by an internal gain of 2.5 within the limits of 1.3 V to 3.09 V. This scheme adjusts the output voltage of the DC/DC converter and therefore the output power of an RF-PA. The TPS62700 operates in fixed-frequency PWM mode at a 2.0-MHz switching frequency to minimize RF interference. This converter operates with only three small external components; an input capacitor, inductor and output capacitor. APPLICATIONS • • Cell Phones, Smart Phones Battery-Powered RF Amplifier The TPS62700 is available in a tiny 8 pin lead free WCSP package for smallest solution size. TYPICAL APPLICATION VIN 2.5 V to 6.0 V 3.3 mH 10 mF AVIN PVIN SW FB VOUT = 2.5 x VCON 1.3 V to 3.09 V 4.7 mF EN VCON AGND PGND 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 © 2007–2008, Texas Instruments Incorporated TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 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 TA PART NUMBER (1) PACKAGE ORDERING PACKAGE MARKING –30°C to 85°C TPS62700 WCSP 8 pin TPS62700YZF CKL (1) The package is available in tape on reel. Add R suffix to order quantities of 3000 parts per reel. ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) (1) VALUE UNIT –0.3 to 7 V –0.3 to VIN +0.3, ≤ 7 V –0.3 to 7 V Input voltage range (2) Voltage range at EN, VCON (2) Voltage on SW (2) Peak output current (2) internally limited ESD rating (3) HBM Human body model 2 Machine model kV 200 V TJ Maximum operating junction temperature –40 to 150 °C Tstg Storage temperature range –65 to 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 YZF 110°C/W 900 mW 9 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). RECOMMENDED OPERATING CONDITIONS over operating free-air temperature range (unless otherwise noted) MIN NOM MAX UNIT VIN, AVIN, PVIN Supply voltage 2.5 6 V TA Operating ambient temperature –40 85 °C TJ Operating junction temperature –40 125 °C 2 Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 ELECTRICAL CHARACTERISTICS PVIN = AVIN = VIN = 3.6 V, EN = AVIN, TA = TJ = –40°C to 85°C typical values are at TA = 25°C (unless otherwise noted), see parameter measurement information PARAMETER TEST CONDITIONS MIN TYP MAX UNIT SUPPLY AVIN, PVIN Input voltage range IOUT IOUT Output current VIN 2.5 to 6 V IQ Operating quiescent current into AVIN VCON = 1 V, FB = 0 V, VIN = 3.6V, device not switching (1) ISD Shutdown current EN = SW=VCON = AGND, AVIN = PVIN = 3.6V max = 650 mA 2.5 6 V 650 mA 0.1 0.3 mA 0.01 2 µA V ENABLE VIH High Level Input Voltage, EN 1.2 VIN VIL Low Level Input Voltage, EN 0 0.4 V IIN Input bias Current, EN 5 10 µA V EN = AVIN CONTROL INPUT VCON VVCON, MIN VCON Threshold forcing VFB, MIN Falling VCON signal 0.484 0.52 0.556 VVCON, MAX VCON Threshold forcing VFB,MAX Rising VCON signal 1.211 1.236 1.26 ZVCON VCON Input resistance CVCON VCON Input capacitance IIN VCON Input current VCON Gain Internal Gain VOUT/VCON 100 VCON = 1 V, f = 100 kHz 0.556 V ≤ VCON ≤ 1.208 V V kΩ 20 pF 10 µA 2.5 POWER SWITCH 100 140 230 PVIN = VGS = 3.6 V Low-Side MOSFET on-resistance PVIN = VGS = 3.6 V Forward current limit MOSFET high side and low side PVIN = 3.6 V 935 1100 1200 mA 3 V < VIN < 5 V 1.7 2.0 2.3 MHz RDS(ON) ILIMF TA = TJ = 25°C High side MOSFET on-resistance TA = TJ = –40°C to 85°C TA = TJ = 25°C 270 180 200 TA = TJ = –40°C to 85°C 330 430 mΩ mΩ OSCILLATOR fSW Oscillator frequency FEEDBACK/OUTPUT VCON = 0.4 V (2) (3) 1.25 1.3 1.35 V Feedback voltage VCON = 1.1 V (2) (3) 2.693 2.75 2.835 V Maximum feedback voltage VCON = 1.4 V (2) (3) 3.028 3.09 3.15 V Linearity in VCON range 0.556 V to 1.208 V (2) (3) 2 % VOUT Rise time from 1.3 V to 3.09 V VIN = 4.2 V, COUT = 4.7 µF, L = 3.3 µH, RLOAD = 5 Ω 20 30 VOUT Fall time from 3.09 V to 1.3 V VIN = 4.2 V, COUT = 4.7 µF, L = 3.3 µH, RLOAD = 10 Ω 20 30 T_ON Start-up Time From Enable low to high transition until VOUT reaches 3.09 V, COUT = 4.7 µF, L = 3.3 µH, IOUT ≤ 1 mA 190 300 η Efficiency (L = 3.3µH, DCR ≤ 100mΩ) VIN = 3.6 V, VOUT = 1.3 V, IOUT = 150 mA VFB, MIN VFB VFB, MAX Linearity TRESPONSE Minimum feedback voltage –2 (3) (4) µs (3) (4) (5) (3) VIN = 3.6 V, VOUT = 3.09 V, IOUT = 400 mA 87 (5) (3) µs % 95 VOUT_RIPPLE Ripple voltage, PWM mode VIN = 3 V to 4.5 V, VOUT = 1.3 V, IOUT = 10 mA to 400 mA (3) 10 mVp-p Line_tr Line transient response VIN = 600 mV step, over VIN range 3 V to 5.5 V TRISE = TFALL = 10 µs, VOUT = 1.3 V, IOUT = 100 mA (3) 50 mVpk Load_tr Load transient response VIN = 3.1/3.6/4.5 V, VOUT = 1.3 V, transients 0 mA to 100 mA, TRISE = TFALL = 10 µs (3) 50 mVpk (1) (2) (3) (4) (5) Device operating in 100% duty cycle mode 2.5 V ≤ VIN ≤ 6 V, with VIN_MIN = VOUT + 0.5 V The voltage need to be measured on the COUT using appropriate measurement probes. For the measurements, a proper PCB layout and usage of recommended inductors and capacitors are essential. See parameter measurement information. Rise/Fall time valid for VFB within specified limits. Using appropriate inductor with R (DCR) less than 100 mΩ Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 3 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 PIN ASSIGNMENTS CSP-8 CSP-8 TOP VIEW BOTTOM VIEW SW SW PVIN A1 AVIN B1 EN C1 A2 C2 A3 PGND PGND A3 B3 AGND AGND B3 C3 FB FB C3 VCON A2 C2 A1 PVIN B1 AVIN C1 EN VCON TERMINAL FUNCTIONS TERMINAL I/O DESCRIPTION NAME NO. CSP PVIN A1 PWR VIN power supply input for the PMOSFET AVIN B1 PWR VIN analog supply input for the internal analog circuitry EN C1 I Enable input for the device. Set high for operation, low for shutdown. This pin must be terminated. VCON C2 I Voltage control input. This pin controls the output voltage of the converter. The output voltage follows VCON with a gain of 2.5 for 0.556 V ≤ VCON ≤ 1.208 V. FB C3 I Analog Feedback Input Pin for the internal regulation loop. Connect this pin directly to the output capacitor. AGND B3 I Analog GND Pin for the internal analog circuitry. PGND A3 Power GND Pin for the NMOSFET SW A2 Switch Node to the internal PMOSFET and NMOSFET. Connect the external inductor between this pin and the output capacitor. FUNCTIONAL BLOCK DIAGRAM EN PV IN AVIN Current Limit Comparator Thermal Shutdown VCON Limit Clamp Circuit High Side Error Amp . Gain 2.5 VREF Control Stage Integrator Zero-Pole Amp. Gate Driver Anti Shoot-Through PWM Comp. SW Through Softstart Limit Low Side FB Sawtooth Generator 2.0 Mhz Oscillator Current Limit Comparator AGND 4 Submit Documentation Feedback PGND Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 PARAMETER MEASUREMENT INFORMATION VIN 10 mF AVIN 3.3 mH PVIN SW VOUT 4.7 mF/10 mF FB EN VCON AGND PGND L: LPS4018 3.3 mH, DCR 70 mW/VLF3014A 3.3 mH DCR 150 mW CIN: GRM188R60J106M 10 mF Murata 0603 size COUT: GRM188R60J106M 10 mF Murata 0603 size GRM188Ru60J475K 4.7 mF Murata 0603 size DETAILED DESCRIPTION OPERATION The TPS62700 step down converter operates at a 2.0-MHz fixed frequency using pulse-width modulation (PWM) over the entire load range. This ensures low output-voltage ripple for RF-PA power applications. In PWM operation, the converter uses a unique fast-response voltage-mode control scheme to achieve good line and load regulation, allowing the use of small ceramic input and output capacitors. At the beginning of each clock cycle initiated by the clock signal, the High-Side MOSFET switch is turned on. The current flows from the input capacitor via the High-Side MOSFET switch through the inductor to the output capacitor and load. During this phase, the current ramps up until the PWM comparator trips and the control logic turns off the switch. The current limit comparator also turns off the switch when the current limit of the High-Side MOSFET switch is exceeded. After a short dead time to prevent shoot-through, the Low-Side MOSFET rectifier is turned on, and the inductor current ramps down. The current then flows from the inductor to the output capacitor and to the load. It turns back to the inductor through the Low-Side MOSFET rectifier. The next cycle is initiated by the clock signal turning off the Low-Side MOSFET rectifier and turning on the High-Side MOSFET switch. Dynamic Output Voltage Control VCON The output voltage of TPS62700 can be dynamically adjusted with an external analog voltage applied to the pin VCON. This voltage is typically supplied from an external DAC to adjust the supply voltage for the RF Power amplifier, and therefore to determine the RF output power. The output voltage is set to : VOUT = 2.5 x VCON. The output voltage can be set in the range between VFB, MIN (1.3 V) and VFB, MAX (3.09 V). The device provides an internal voltage gain factor of 2.5. For dynamic voltage adjustment the VCON voltage range is between VCON, MIN (0.52 V) and VCON, MAX (1.24 V). In Case the VCON voltage is out of this range, the output voltage is internally limited to VFB, MIN (1.3 V) and VFB, MAX (3.09 V). This allows using the TPS62700 as a fixed output voltage converter where the VCON Pin is connected, for example, to GND or VIN. 100% Duty Cycle Low Dropout Operation The device starts to enter 100% duty-cycle mode when the input voltage approaches the nominal output voltage. In order to maintain the output voltage, the High-Side MOSFET switch is turned on 100% for one or more cycles. Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 5 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 With further decreases of 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 entire battery voltage range. The minimum input voltage to maintain regulation depends on the load current and output voltage, and can be calculated as: VIN _ MIN = VOUT _ MIN + I OUT _ MAX ´ (R DSON _ MAX + R L ) (1) With: IOUT_MAX = maximum output current plus inductor ripple current RDSON_MAX = maximum P-channel switch RDSON. RL = DC resistance of the inductor VOUT_MAX = nominal output voltage plus maximum output voltage tolerance ENABLE The device is enabled by setting the EN pin to high and at first the internal circuits are settled. Afterwards the device activates the soft start circuit and ramps up the output voltage. The output voltage is ramped up from 0 V to 3.09 V within typically 190 µs after the EN pin changes from low to high. A low signal at the EN pin sets the device in Shutdown Mode with less than 2 µA current consumption. SHORT-CIRCUIT PROTECTION The High-Side and Low-Side MOSFET switches are protected with maximum output current = ILIMF in case a short circuit on the output occurs. When the High-Side MOSFET switch reaches its current limit, it is turned off, and the Low-Side MOSFET switch is turned on. The High-Side MOSFET switch can only turn on again, after the current in the Low-Side MOSFET switch decreases below its current limit. 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 by typical 20°C. UNDERVOLTAGE LOCKOUT The device stops operation at typ. 1.5 V with falling input voltage and starts operation at typ. 1.7 V with rising input voltage. This prevents malfunction of the device due to low input voltage. TYPICAL CHARACTERISTICS Typical Characteristic Graphs FIGURE Switching Frequency vs Input Voltage (VIN) Figure 1 RDSON vs VIN, N-Channel Figure 2 RDSON vs VIN, P-Channel Figure 3 Shutdown Current (ISD) vs Temperature Figure 4 Quiescent Current (IQ) into AVIN vs VIN Figure 5 EN High Threshold Voltage vs VIN Figure 6 Efficiency vs Output Current Figure 7 Efficiency vs Output Current Figure 8 Efficiency vs Output Voltage Figure 9 Efficiency vs Output Voltage Figure 10 Output Voltage vs Output Current (VOUT = 1.3 V, TA = 25°C) Figure 11 Output Voltage vs Output Current (VOUT = 1.3 V, TA = –40°C) Figure 12 Output Voltage vs Output Current (VOUT = 1.3 V, TA = 85°C) Figure 13 Output Voltage vs Output Current (VOUT = 2.75 V, TA = 25°C) Figure 14 6 Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 TYPICAL CHARACTERISTICS (continued) Typical Characteristic Graphs (continued) FIGURE Output Voltage vs Output Current (VOUT = 2.75 V, TA = –40°C) Figure 15 Output Voltage vs Output Current (VOUT = 2.75 V, TA = 85°C) Figure 16 Output Voltage vs Output Current (VOUT = 3.09 V, TA = 25°C) Figure 17 Output Voltage vs Output Current (VOUT = 3.09 V, TA = –40°C) Figure 18 Output Voltage vs. VCON Voltage (VI = 4.2 V) Figure 19 Output Voltage vs Output Current (VOUT = 3.09 V, TA = 85°C) Figure 20 Output Voltage VOUT vs VCON Voltage Figure 21 VCON Max Threshold VOUT TA = 25°C Figure 22 VCON Max Threshold VOUT TA = 85°C Figure 23 VCON Max Threshold VOUT TA =–40°C Figure 24 VCON Min Threshold VOUT TA = 25°C Figure 25 VCON Min Threshold VOUT TA = 85°C Figure 26 VCON Min Threshold VOUT TA =–40°C Figure 27 Load Transient Response VOUT = 1.3 V Figure 28 Load Transient Response VOUT = 3.09 V Figure 29 Load Transient Response VOUT = 3.09 V Figure 30 Load Transient Response VOUT = 3.09 V Figure 31 PWM Mode Operation VOUT = 1.3 V Figure 32 PWM Mode Operation VOUT = 3.09 V Figure 33 Output Voltage Ripple At High Duty Cycle Operation Figure 34 VCON Voltage Response Figure 35 VCON Output Voltage Response And Synchronous Applied Load Transient Figure 36 Startup VOUT 1.3 V Figure 37 Startup VOUT 3.09 V Figure 38 Line Transient Response Figure 39 RDSON vs INPUT VOLTAGE VIN, N-CHANNEL 2.30 Switching Frequency - MHz 2.20 TA = 20°C TA = 85°C 2.10 2.00 TA = 0°C TA = -30°C 1.90 1.80 1.70 2.5 3 3.5 4 4.5 5 VI - Input Voltage - V 5.5 6 rDS(on) - Static Drain-Source on-State Resistance - W SWITCHING FREQUENCY vs VIN 0.40 0.35 0.30 TA = 85°C 0.25 TA = 25°C TA = -40°C 0.20 0.15 0.10 0.05 2.5 3 3.5 4 4.5 5 5.5 6 VI - Input Voltage - V Figure 1. Figure 2. Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 7 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 SHUTDOWN CURRENT (ISD) vs TEMPERATURE 0.25 125 EN = 0 V 0.23 0.21 100 TA = 85°C 0.19 0.17 Shutdown Current - nA rDS(on) - Static Drain-Source on-State Resistance - W RDSON vs VIN, P-CHANNEL TA = 25°C 0.15 TA = -40°C 0.13 0.11 0.09 VI = 5.5 V 75 VI = 4.5 V VI = 3.5 V 50 VI = 2.5 V 25 0.07 0.05 2.5 3 3.5 4 4.5 5 VI - Input Voltage - V 5.5 0 -40 6 -20 0 20 40 60 TA - Ambient Temperature - °C Figure 3. Figure 4. QUIESCENT CURRENT (IQ) INTO AVIN vs VIN EN HIGH THRESHOLD VOLTAGE vs VIN 140 80 100 1 TA = -40°C 0.9 100 TA = 25°C TA = 55°C TA = 85°C EN High Threshold - V Quiescent Current - mA 120 80 60 40 TA = -40°C TA = 0°C 0.8 0.7 TA = 55°C 3 3.5 4 4.5 5 VI - Input Voltage - V 5.5 6 0.4 2.5 3 3.5 4 4.5 5 5.5 6 VI - Input Voltage - V Figure 5. 8 TA = 85°C 0.6 0.5 20 0 2.5 TA = 25°C TA = 0°C Figure 6. Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 EFFICIENCY vs OUTPUT CURRENT EFFICIENCY vs OUTPUT CURRENT 100 100 95 VI = 2.7 V VI = 3 V VI = 3.6 V 95 L = 3.3 mH, DCR < 100 mW 90 Efficiency - % 90 Efficiency - % VI = 3.3 V VO = 1.3 V 85 VI = 4.2 V 80 VI = 5.5 V 75 VI = 3.6 V VI = 4.2 V 85 VI = 5.5 V 80 75 70 70 65 65 VO = 3.09 V 60 L = 3.3 mH, DCR < 100 mW 60 0 0.6 0.2 0.4 IO - Output Current - A 0 Figure 7. Figure 8. EFFICIENCY vs OUTPUT VOLTAGE EFFICIENCY vs OUTPUT VOLTAGE 100 VI = 3.6 V, L = 3.3 mH, DRC < 100 mW 95 Efficiency - % Efficiency - % L = 3.3 mH, DRC < 100 mW 90 90 RL = 5 W 85 RL = 10 W RL = 15 W 80 RL = 5 W RL = 10 W 85 RL = 15 W 80 75 70 1.3 0.6 100 VI = 4.2 V, 95 0.2 0.4 IO - Output Current - A 75 1.5 1.7 1.9 2.1 2.3 2.5 2.7 VO - Output Voltage - V 2.9 3.1 70 1.3 1.5 Figure 9. 1.7 1.9 2.1 2.3 2.5 2.7 VO - Output Voltage - V 2.9 3.1 Figure 10. Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 9 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 OUTPUT VOLTAGE vs OUTPUT CURRENT OUTPUT VOLTAGE vs OUTPUT CURRENT 1.339 1.339 TA = 25°C, VCON = 0 V, VO = 1.3 V 1.326 VO - Output Voltage - V VO - Output Voltage - V 1.326 1.313 1.3 VI = 2.7 V, VI = 3.3 V, VI = 3.6 V, VI = 4.2 V, VI = 5.5 V 1.287 1.274 1.313 1.3 VI = 2.7 V, VI = 3.3 V, VI = 3.6 V, VI = 4.2 V, VI = 5.5 V 1.287 1.274 1.261 1.261 0 0.2 0.4 IO - Output Current - A 0.6 0 0.4 IO - Output Current - A Figure 12. OUTPUT VOLTAGE vs OUTPUT CURRENT OUTPUT VOLTAGE vs OUTPUT CURRENT 0.6 2.833 TA = 85°C, VCON = 0 V, VO = 1.3 V 1.313 1.3 VI = 2.7 V, VI = 3.3 V, VI = 3.6 V, VI = 4.2 V, VI = 5.5 V 1.287 1.274 TA = 25°C, VCON = 1.1 V, VO = 2.75 V 2.805 VO - Output Voltage - V 1.326 2.778 2.750 VI = 3.3 V, VI = 3.6 V, VI = 4.2 V, VI = 5.5 V 2.723 2.695 1.261 2.668 0 0.2 0.4 IO - Output Current - A 0.6 0 Figure 13. 10 0.2 Figure 11. 1.339 VO - Output Voltage - V TA = -40°C, VCON = 0 V, VO = 1.3 V 0.2 0.4 IO - Output Current - A 0.6 Figure 14. Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 OUTPUT VOLTAGE vs OUTPUT CURRENT OUTPUT VOLTAGE vs OUTPUT CURRENT 2.833 2.833 TA = -40°C, VCON = 1.1 V, VO = 2.75 V 2.805 VO - Output Voltage - V VO - Output Voltage - V 2.805 2.778 2.750 VI = 3.3 V, VI = 3.6 V, VI = 4.2 V, VI = 5.5 V 2.723 2.695 TA = 85°C, VCON = 1.1 V, VO = 2.75 V 2.778 2.750 VI = 3.3 V, VI = 3.6 V, VI = 4.2 V, VI = 5.5 V 2.723 2.695 2.668 2.668 0 0.2 0.4 0.6 0 0.2 IO - Output Current - A Figure 15. Figure 16. OUTPUT VOLTAGE vs OUTPUT CURRENT OUTPUT VOLTAGE vs OUTPUT CURRENT 3.09 VI = 3.6 V, VI = 4.2 V, VI = 5.5 V 3.121 3.09 VI = 3.6 V, VI = 4.2 V, VI = 5.5 V 3.059 3.028 3.028 2.997 0 TA = -40°C, VCON = 1.4 V, VO = 3.09 V 3.152 VO - Output Voltage - V VO - Output Voltage - V TA = 25°C, VCON = 1.4 V, VO = 3.09 V 3.121 3.059 0.6 3.183 3.183 3.152 0.4 IO - Output Current - A 2.997 0.2 0.4 IO - Output Current - A 0.6 0 Figure 17. 0.2 0.4 IO - Output Current - A 0.6 Figure 18. Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 11 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 VOUT OUTPUT VOLTAGE vs VCON VOLTAGE OUTPUT VOLTAGE vs OUTPUT CURRENT 3.2 3.183 VI = 4.2 V RL = 8 Ω 3.0 3.152 2.8 2.6 VO - Output Voltage - V VO − Output Voltage − V TA = 85°C, VCON = 1.4 V, VO = 3.09 V 2.4 2.2 TA = −40°C, TA = 25°C, TA = 85°C 2.0 1.8 3.121 3.09 VI = 3.6 V, VI = 4.2 V, VI = 5.5 V 3.059 1.6 3.028 1.4 1.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.997 0 0.2 0.4 IO - Output Current - A VCON − Voltage Control − V Figure 19. Figure 20. OUTPUT VOLTAGE VOUT vs VCON VOLTAGE VCON MAX THRESHOLD vs VOUT TA = 25°C 3.150 3.150 TA = 25°C, TA = 25°C, RL = 8W 3.130 VO - Output Voltage - V VO - Output Voltage - V 3.130 3.110 VI = 4.5 V 3.090 3.070 VI = 5.5 V VI = 3.5 V 3.050 3.030 1.230 12 0.6 RL = 8W 3.110 VI = 4.5 V 3.090 3.070 VI = 5.5 V VI = 3.5 V 3.050 1.232 1.234 1.236 1.238 VCON - Max Threshold - V Figure 21. 1.240 3.030 1.230 Submit Documentation Feedback 1.232 1.234 1.236 1.238 VCON - Max Threshold - V Figure 22. 1.240 Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 VCON MAX THRESHOLD vs VOUT TA = 85°C VCON MAX THRESHOLD vs VOUT TA = –40°C 3.150 3.150 TA = -40°C, TA = 25°C, R L = 8W 3.130 VO - Output Voltage - V VO - Output Voltage - V 3.130 3.110 VI = 4.5 V 3.090 VI = 5.5 V 3.070 VI = 3.5 V R L = 8W 3.110 VI = 4.5 V 3.090 VI = 5.5 V 3.070 3.050 3.050 3.030 1.230 1.232 1.234 1.236 1.238 VCON - Max Threshold - V 3.030 1.230 1.240 1.232 VCON MIN THRESHOLD vs VOUT TA = 25°C 1.310 TA = 25°C, VI = 4.5 V 1.304 1.302 VI =2.5 V VI = 3.5 V 1.298 1.296 1.240 TA = 85°C, RL = 8W 1.304 1.300 1.298 1.292 1.292 0.525 VI = 2.5 V VI = 3.5 V 1.296 1.294 0.517 0.519 0.521 0.523 VCON - Max Threshold - V Figure 25. VI = 5.5 V VI = 4.5 V 1.302 1.294 1.290 0.515 1.238 1.306 VI = 5.5 V VO - Output Voltage - V VO - Output Voltage - V 1.308 R L = 8W 1.306 1.236 VCON MIN THRESHOLD vs VOUT TA = 85°C 1.310 1.308 1.234 VCON - Max Threshold - V Figure 24. Figure 23. 1.300 VI = 3.5 V 1.290 0.515 Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 0.517 0.519 0.521 0.523 0.525 Submit Documentation Feedback 13 VCON - Min Threshold - V Figure 26. TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 VCON MIN THRESHOLD vs VOUT TA =–40°C LOAD TRANSIENT RESPONSE VOUT = 1.3 V 1.310 TA = -40°C, 1.308 RL = 8W 1.306 VO - Output Voltage - V VI = 3.6 V, L = 3.3 mH, CO = 4.7 mF VO = 1.3 V, IO = 50 mA to 250 mA, VO = 50 mV/div VCON = AGND VI = 4.5 V VI = 5.5 V 1.304 IO = 200 mA/div 1.302 1.300 VI = 2.5 V VI = 3.5 V 1.298 250 mA 1.296 IO = 200 mA/div 1.294 50 mA 1.292 1.290 0.515 0.517 0.519 0.521 0.523 VCON - Min Threshold - V Figure 27. LOAD TRANSIENT RESPONSE VOUT = 3.09 VI = 4.2 V, L = 3.3 mH, CO = 4.7 mF VO = 3.09 V, IO = 100 mA to 400 mA, VCON = AVIN VO = 100 mV/div Time base - 10 ms/div 0.525 Figure 28. LOAD TRANSIENT RESPONSE VOUT = 3.09 V VI = 4.2 V, L = 2.2 mH, CO = 10 mF VO = 3.09 V, IO = 100 mA to 400 mA, VCON = AVIN VO = 100 mV/div IO = 200 mA/div IO = 200 mA/div 400 mA 400 mA IO = 200 mA/div IO = 200 mA/div 100 mA Time base - 10 ms/div Time base - 10 ms/div Figure 29. 14 100 mA Figure 30. Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 LOAD TRANSIENT RESPONSE VOUT = 3.09 V VI = 4.2 V, VO = 3.09 V, IO = 100 mA to 400 mA, VCON = AVIN PWM MODE OPERATION VOUT = 1.3 V L = 3.3 mH, CO = 10 mF VO = 1.3 V VO = 100 mV/div VI = 3.6 V, IL = 200 mA, VCON = 0 V, L = 3.3 mH, CO = 4.7 mF VO = 10 mV/div IO = 200 mA/div IO = 100 mA/div SW 2 V/div 400 mA IO = 200 mA/div 100 mA Time base - 10 ms/div Time base - 200 ns/div Figure 31. Figure 32. PWM MODE OPERATION VOUT = 3.09 V OUTPUT VOLTAGE RIPPLE AT HIGH DUTY CYCLE OPERATION VO = 10 mV/div VI = 3.6 V, IL = 200 mA, VCON = VI, VO = 10 mV/div VO = 3.09 V IO = 100 mA/div L = 3.3 mH, CO = 4.7 mF VI = 3.26 V, IL = 200 mA, VCON = VI, VO = 3.09 V IO = 200 mA/div L = 3.3 mH, CO = 4.7 mF SW 2 V/div SW 2 V/div Time base - 200 ns/div Time base - 1 ms/div Figure 33. Figure 34. Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 15 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 VCON OUTPUT VOLTAGE RESPONSE AND SYNCHRONOUS APPLIED LOAD TRANSIENT VCON VOLTAGE RESPONSE 1.4 V 1.4 V VCON = 1 V/div VCON = 1 0V 0V VO = 3.09 V VO = 3.09 V VO 1 V/div VO = 1 V/div VO = 1.3 V VO = 1.3 V VI = 4.2 V, IL = 100 mA/400 mA, VCON = 0 V/1.4 V ICOIL = 500 mA/div ICOIL = 1000 mA/div VI = 4.2 V, RL = 10 W 400 mA L= 3.3 mH, CO = 4.7 mF IO = 500 mA/div 100 mA Time base - 25 ms/div Time base - 50 ms/div Figure 35. Figure 36. STARTUP VOUT 1.3 V STARTUP VOUT 3.09 V EN = 5 V/div EN = 5 V/div 3.09 V 1.3 V VI = 4.2 V, VI = 3.6 V, RL = 10 W, VCON = 0 V, VO = 1.3 V VO = 500 mV/div 0V 0V II = 500 mA/div II = 500 mA/div ICOIL = 500 mA/div ICOIL = 500 mA/div Time base - 40 ms/div Time base - 40 ms/div Figure 37. 16 VO = 1 mV/div RL = 10 W, VCON = 1.4 V, VO = 3.09 V Figure 38. Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 LINE TRANSIENT RESPONSE VI = 500 mA/div 4.2 V VI = 3.6 V to 4.2 V, IL = 100 mA, VCON = 1.4 V, L = 3.3 mH, 3.6V CO = 10 mF, VO = 3.09 V VO = 10 mV/div ICOIL = 100 mA/div Time base - 40 ms/div Figure 39. Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 17 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 APPLICATION INFORMATION VI 2.5 V to 6.0 V 3.3 mH 10 mF AVIN VO = 2.5 x VCON 1.3 V to 3.09 V PVIN SW Controller 4.7 mF FB ON/OFF EN DAC VCON AGND PGND Figure 40. TPS62700 Application Circuit VI 3.3 V to 6 V 10 mF AVIN 2.2/2.7/3.3 mH PVIN VO 3.09 V SW FB 10 mF EN VCON AGND PGND Figure 41. TPS62700 With Fixed VOUT 3.09 V 18 Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 OUTPUT FILTER DESIGN (INDUCTOR AND OUTPUT CAPACITOR) Inductor Selection The inductor value has a direct effect on the ripple current. The selected inductor must have adequate ratings for dc resistance and saturation current. The inductor ripple current (ΔIL) decreases with higher inductance and increases with higher VIN or VOUT. Equation 2 calculates the maximum inductor current under static load conditions. The saturation current of the inductor should be rated higher than the maximum peak inductor current as calculated with Equation 3. This is recommended because during heavy load transients, the inductor current rises above the calculated value. V 1 - OUT VIN DIL = VOUT ´ I´ f (2) DI L IL _ MAX = IOUT _ MAX + 2 (3) Where f = Switching Frequency (2.0 MHz typical) L = Inductor Value ΔIL = Peak to Peak inductor ripple current IL_MAX = Maximum Inductor current A good approach is to select the inductor current and inductance rating for the maximum switch current limit of the TPS62700. Accepting larger values of ripple current allows the use of lower inductance values, but results in higher output-voltage ripple, greater core losses, and lower output-current capability. The total losses of the inductor have a strong impact on the efficiency of the DC/DC conversion and consist of both the losses in the dc resistance L) 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 Table 1. List Of Inductors DIMENSIONS INDUCTOR Series SUPPLIER 2.5 × 2.0 × 1.2 KSLI-252012AG 2.5 × 2.0 × 1.2 MIPSA2520 FDK Murata 2.5x2.0x1.2 LQM2HPN 2.8 × 2.6 × 1.4 VLF3014AT 3.9 × 3.9 × 1.7 LPS4018 Hitachi Metals TDK Coilcraft Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 19 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 Output Capacitor Selection The advanced, fast-response, voltage-mode control scheme of the TPS62700 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 nominal load current, the device operates in PWM mode, and the RMS ripple current is calculated as: V 1 - OUT VIN 1 IRMSCout = VOUT ´ ´ L´f 2´ 3 (4) At nominal load current, the device operates in PWM mode and the overall output voltage ripple is the sum of the voltage spike caused by the output capacitor ESR plus the voltage ripple caused by charging and discharging the output capacitor: V 1 - OUT æ ö VIN 1 DVOUT = VOUT ´ ´ çç + ESR ÷÷ L´f è 8 ´ C out ´ f ø (5) Input Capacitor Selection Because of the nature of the buck converter due to its pulsating input current, a low-ESR input capacitor is required for best input-voltage filtering, and to minimize interference with other circuits caused by high input-voltage spikes. For most applications, a 10-µF ceramic capacitor is recommended. The input capacitor can be increased without any limit for better input-voltage filtering. 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. List Of Capacitors 20 Size Capacitance µF 0603 0603 TYPE SUPPLIER 4.7 GRM188R60J475K Murata 10 GRM188R60J106M Murata Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 TPS62700 www.ti.com SLVS784A – DECEMBER 2007 – REVISED MARCH 2008 LAYOUT CONSIDERATIONS As for all switching power supplies, the PCB 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 achieve 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, short traces for the main current paths. The input capacitor should be placed as close as possible to the IC pins PVIN and PGND. The inductor and output capacitor should be placed close to SW and PGND. The FB line should be connected directly to the output capacitor and routed away from noisy components and traces (e.g., SW line). VOUT COUT G D N VCON ENABLE 0è L CIN VIN Figure 42. Suggested Board Layout PACKAGE SUMMARY CHIP SCALE PACKAGE (BOTTOM VIEW) CHIP SCALE PACKAGE (TOP VIEW) SW PGND D A3 AGND B3 FB C3 A2 C2 A1 PV IN B1 AVIN C1 EN VCON E YMLLLL CKL S A1 Code: - YM: 2 digit year/month date code - LLLL: lot trace code - S: assembly site code - CKL: TPS62700 device code PACKAGE DIMENSIONS Dimension D Dimension E2 1,64 mm ± 0.03mm 1,5 mm ± 0.03 Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS62700 21 PACKAGE MATERIALS INFORMATION www.ti.com 11-Mar-2008 TAPE AND REEL INFORMATION *All dimensions are nominal Device TPS62700YZFR Package Package Pins Type Drawing SPQ DSBGA 3000 YZF 8 Reel Reel Diameter Width (mm) W1 (mm) 178.0 8.4 Pack Materials-Page 1 A0 (mm) B0 (mm) K0 (mm) P1 (mm) 1.6 1.74 0.81 4.0 W Pin1 (mm) Quadrant 8.0 Q1 PACKAGE MATERIALS INFORMATION www.ti.com 11-Mar-2008 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) TPS62700YZFR DSBGA YZF 8 3000 217.0 193.0 35.0 Pack Materials-Page 2 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. 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