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TPS54495RSAR

TPS54495RSAR

  • 厂商:

    BURR-BROWN(德州仪器)

  • 封装:

    VQFN-16_4X4MM-EP

  • 描述:

    TPS54495 4.5V TO 18V INPUT, DUAL

  • 数据手册
  • 价格&库存
TPS54495RSAR 数据手册
TPS54495 www.ti.com SLVSBH0A – JUNE 2012 – REVISED MAY 2013 4A/2A Dual Channel Synchronous Step-Down Switcher with Integrated FET Check for Samples: TPS54495 FEATURES APPLICATIONS • • 1 2 • • • • • • • • • • • • • • • • D-CAP2™ Control Mode – Fast Transient Response – No External Parts Required For Loop Compensation – Compatible with Ceramic Output Capacitors Wide Input Voltage Range : 4.5 V to 18 V Output Voltage Range : 0.76 V to 7 V Highly Efficient Integrated FETs Optimized for Low Duty Cycle Applications – 90 mΩ (High Side) and 60 mΩ (Low Side) High Initial Reference Accuracy Supports Constant 4 A CH1 and 2 A CH2 Load Current Low-Side rDS(on) Loss-Less Current Sensing Adjustable Soft Start Non-Sinking Pre-Biased Soft Start 700 kHz Switching Frequency Cycle-by-Cycle Over-Current Limit Control OCL/UVLO/TSD Protections Hiccup Timer for Overload Protection Adaptive Gate Drivers with Integrated Boost PMOS Switch OCP Constant Due To Thermally Compensated rDS(on) with 4000ppm/℃ ℃ 16-Pin HTSSOP, 16-Pin VQFN Auto-Skip Eco-mode™   for High Efficiency at Light Load Point-of-Load Regulation in Low Power Systems for Wide Range of Applications – Digital TV Power Supply – Networking Home Terminal – Digital Set Top Box (STB) – DVD Player/Recorder – Gaming Consoles and Other DESCRIPTION The TPS54495 is a dual, adaptive on-time D-CAP2™ mode synchronous buck converter. The TPS54495 enables system designers to complete the suite of various end equipment’s power bus regulators with a cost effective, low component count, and low standby current solution. The main control loops of the TPS54495 use the D-CAP2™ mode control which provides a very fast transient response with no external compensation components. The adaptive ontime control supports seamless transition between PWM mode at higher load conditions and Ecomode™ operation at light loads. Eco-mode™ allows the TPS54495 to maintain high efficiency during lighter load conditions. The TPS54495 is able to adapt to both low equivalent series resistance (ESR) output capacitors such as POSCAP or SP-CAP, and ultra-low ESR, ceramic capacitors. The device provides convenient and efficient operation with input voltages from 4.5V to 18V. The TPS54495 is available in a 4.4 mm × 5 mm 16pin TSSOP (PWP) package and 4 mm x 4 mm 16-pin VQFN (RSA), and is designed to operate for an ambient temperature range from –40°C to 85°C. Input Voltage Vout2(50mV/div) 1 VIN1 2 VBST1 3 SW1 C11 VO1 L11 VIN2 16 C32 VO2 C22 4 PGND PGND1 TPS54495 HTSSOP16 PGND2 13 Iout2(1A/div) PGND 5 EN1 EN2 12 6 SS1 SS2 11 7 VFB1 VFB2 10 C41 R21 L12 SW2 14 C21 R11 C12 VBST2 15 C31 C42 SGND SGND C5 8 GND VREG5 SGND 9 PGND R12 R22 100 ms/div SGND 1 2 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. D-CAP2, Eco-mode, Eco-Mode are trademarks of Texas Instruments. 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 © 2012–2013, Texas Instruments Incorporated TPS54495 SLVSBH0A – JUNE 2012 – REVISED MAY 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) TA PACKAGE (2) (3) ORDERING PART NUMBER TPS54495PWPR PWP TPS54495PWP –40℃ to 85℃ TPS54495RSAR RSA (1) (2) (3) TPS54495RSAT PINS OUTPUT SUPPLY Tape-and-Reel 16 Tube 16 Tape-and-Reel For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI web site at www.ti.com Package drawings, thermal data, and symbolization are available at www.ti.com/packaging. All packaging options have Cu NIPDAU lead/ball finish. ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) (1) (2) VALUE Input voltage range Output voltage range Electrostatic discharge UNIT VIN1, VIN2, EN1, EN2 –0.3 to 20 VBST1, VBST2 –0.3 to 26 VBST1, VBST2 (10ns transient) –0.3 to 28 VBST1–SW1 , VBST2–SW2 –0.3 to 6.5 VFB1, VFB2 –0.3 to 6.5 SW1, SW2 –2 to 20 SW1, SW2 (10ns transient) –3 to 22 VREG5, SS1, SS2 –0.3 to 6.5 PGND1, PGND2 –0.3 to 0.3 Human Body Model (HBM) 2 V kV 500 V TA Operating ambient temperature range –40 to 85 °C TSTG Storage temperature range –55 to 150 °C TJ Junction temperature range –40 to 150 °C (1) (2) Charged Device Model (CDM) V 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" are not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. All voltages are with respect to IC GND terminal. THERMAL INFORMATION THERMAL METRIC (1) TPS54495 PWP (16) PINS RSA (16) PINS θJA Junction-to-ambient thermal resistance 41.4 32.8 θJCtop Junction-to-case (top) thermal resistance 27.8 35.4 θJB Junction-to-board thermal resistance 23.2 9.9 ψJT Junction-to-top characterization parameter 0.9 0.4 ψJB Junction-to-board characterization parameter 23.0 10.0 θJCbot Junction-to-case (bottom) thermal resistance 3.5 1.6 (1) 2 UNITS °C/W For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953. Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated Product Folder Links: TPS54495 TPS54495 www.ti.com SLVSBH0A – JUNE 2012 – REVISED MAY 2013 RECOMMENDED OPERATING CONDITIONS over operating free-air temperature range (unless otherwise noted) VALUES Supply input voltage range Input voltage range VIN1, VIN2 MAX UNIT 4.5 18 VBST1, VBST2 –0.1 24 VBST1, VBST2 (10ns transient) –0.1 27 VBST1–SW1, VBST2–SW2 –0.1 5.7 VFB1, VFB2 –0.1 5.7 EN1, EN2 –0.1 18 SW1, SW2 –1.0 18 SW1, SW2 (10ns transient) Output voltage range MIN V –3 21 VREG5, SS1, SS2 –0.1 5.7 PGND1, PGND2 –0.1 0.1 VO1, VO2 0.76 7.0 V V TA Operating free-air temperature –40 85 °C TJ Operating Junction Temperature –40 150 °C ELECTRICAL CHARACTERISTICS (1) over recommended free-air temperature range, VIN = 12 V (unless otherwise noted) PARAMETER CONDITIONS MIN TYP MAX UNIT 1200 2000 µA 15 20 µA 765 773 mV 115 ppm/℃ 0.4 µA SUPPLY CURRENT IIN VIN supply current TA = 25°C, EN1 = EN2 = 5 V, VFB1 = VFB2 = 0.8 V IVINSDN VIN shutdown current TA = 25°C, EN1 = EN2 = L after H FEEDBACK VOLTAGE VVFBTHLx VFBx threshold voltage TA = 25°C, CH1 = 3.3 V, CH2 = 1.5 V TCVFBx Temperature coefficient On the basis of 25°C (2) –115 758 IVFBx VFBx Input Current VFBx = 0.8 V, TA = 25°C –0.4 0.2 VREG5 OUTPUT VVREG5 VREG5 output voltage TA = 25°C, 6 V < VIN1 < 18 V, IVREG = 5 mA 5.5 V IVREG5 Output current VIN1 = 6 V, VREG5 = 4.0 V, TA = 25°C (2) 75 mA High side switch resistance TA = 25℃, VBSTx-SWx = 5.5 V 90 mΩ 60 mΩ MOSFETs rDS(on)H rDS(on)L Low side switch resistance TA = 25℃ (2) (2) ON-TIME TIMER CONTROL TON1 SW1 On Time SW1 = 12 V, VO1 = 1.2 V 165 ns TON2 SW2 On Time SW2 = 12 V, VO2 = 1.2 V 165 ns (2) 220 ns 220 ns TOFF1 SW1 Min off time TA = 25℃, VFB1 = 0.7 V TOFF2 SW2 Min off time TA = 25℃, VFB2 = 0.7 V (2) ISSC SSx charge current VSSx = 0.5 V, TA = 25℃ TCISSC ISSC temperature coefficient On the basis of 25°C (2) ISSD SSx discharge current VSSx = 0.5 V SOFT START (1) (2) –8.4 –8.0 –5 3 7 –7.6 µA 4 nA/°C 10 mA x means either 1 or 2, that is VFBx means VFB1 or VFB2. Specified by design. Not production tested. Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated Product Folder Links: TPS54495 3 TPS54495 SLVSBH0A – JUNE 2012 – REVISED MAY 2013 www.ti.com ELECTRICAL CHARACTERISTICS(1) (continued) over recommended free-air temperature range, VIN = 12 V (unless otherwise noted) PARAMETER CONDITIONS MIN TYP MAX UNIT UVLO VUVREG5 VREG5 UVLO threshold VREG5 rising 3.83 Hysteresis V 0.6 LOGIC THRESHOLDs VENxH ENx H-level threshold voltage VENxL ENx L-level threshold voltage RENx_IN ENx input resistance 2.0 V 0.4 V ENx = 12V 225 450 900 kΩ CURRENT LIMITs IOCL1 CH1 Current limit LOUT1 = 2.2 µH (3) 4.5 5.7 7.0 A IOCL2 CH1 Current limit LOUT2 = 1.5 µH (3) 2.8 3.9 5.0 A 63% 68% 73% OUTPUT UNDERVOLTAGE AND OVERVOLTAGE PROTECTION (UVP, OVP) VUVP Output UVP trip threshold TUVPDEL Output UVP delay time TUVPEN Output UVP enable delay measured on VFBx 1.5 UVP enable delay / softstart time x 1.4 x 1.7 ms x 2.0 THERMAL SHUTDOWN TSD (3) 4 Thermal shutdown threshold Shutdown temperature (3) Hysteresis (3) 155 25 °C Specified by design. Not production tested. Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated Product Folder Links: TPS54495 TPS54495 www.ti.com SLVSBH0A – JUNE 2012 – REVISED MAY 2013 DEVICE INFORMATION VBST1 3 SW1 4 PGND1 5 EN1 6 SS1 TPS54495 HTSSOP16 16 VBST2 15 SW 2 14 PGND 2 13 EN2 12 VIN1 SS2 11 VBST1 VFB2 10 VREG5 9 SS2 2 VIN2 EN2 VIN1 PGND2 1 RSA PACKAGE (TOP VIEW) SW2 PWP PACKAGE (TOP VIEW) 16 15 14 13 VBST2 1 12 VFB2 VIN2 2 11 VREG5 3 10 GND 4 9 VFB1 PowerPAD GND 6 7 8 SS1 8 5 EN1 VFB1 SW1 7 PGND1 PowerPAD PIN FUNCTIONS (1) PIN NAME I/O PWP RSA VIN1 1 3 I VIN2 16 2 I VBST1 2 4 I VBST2 15 1 I SW1 3 5 I/O SW2 14 16 I/O PGND1 4 6 I/O PGND2 13 15 I/O DESCRIPTION Power inputs and connects to both high side NFET drains. Supply Input for 5.5 V linear regulator. Supply input for high-side NFET gate drive circuit. Connect 0.1 µF ceramic capacitor between VBSTx and SWx pins. An internal diode is connected between VREG5 and VBSTx Switch node connections for both the high-side NFETs and low–side NFETs. Input of current comparator. Ground returns for low-side MOSFETs. Input of current comparator. EN1 5 7 I EN2 12 14 I SS1 6 8 O SS2 11 13 O VFB1 7 9 I VFB2 10 12 I GND 8 10 I/O Signal GND. Connect sensitive SSx and VFBx returns to GND at a single point. VREG5 9 11 O Output of 5.5 V linear regulator. Bypass to GND with a high-quality ceramic capacitor of at least 1 µF. VREG5 is active when VIN1 is added. Back side Back side I/O Thermal pad of the package. Must be soldered to achieve appropriate dissipation. Must be connected to GND. Exposed Thermal Pad (1) Enable. Pull High to enable according converter. Soft-Start Programming Pin. Connect Capacitor from SSx pin to GND to program Soft-Start time. D-CAP2 feedback inputs. Connect to output voltage with resistor divider. x means either 1 or 2, that is. VFBx means VFB1 or VFB2. Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated Product Folder Links: TPS54495 5 TPS54495 SLVSBH0A – JUNE 2012 – REVISED MAY 2013 www.ti.com FUNCTIONAL BLOCK DIAGRAM VIN1 VIN1 - 32 VBST1 UV1 UV 0.1uF SW1 Ref1 SS1 VO1 PGND1 Err Comp PGND1 VFB1 Ref_OCL PGND1 SW1 OCP1 EN1 EN2 EN Logic SW1 ZC1 EN Logic VIN1 VREG5 GND CH1 Min- off timer 5VREG 1.0 uF CH2 Min- off timer SS1 SS1 SS2 SoftStart UV1 UV2 SS2 CSS1 UVLO TSD CSS2 -32 UV Ref1 Ref2 REF UVLO Protection Logic VIN2 VIN2 VBST2 UV2 0.1uF VO2 SW2 Ref2 SS2 PGND2 Err Comp PGND2 VFB2 Ref_OCL PGND2 SW2 OCP2 6 SW2 ZC2 Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated Product Folder Links: TPS54495 TPS54495 www.ti.com SLVSBH0A – JUNE 2012 – REVISED MAY 2013 OVERVIEW The TPS54495 is a 4A/2A dual synchronous step-down (buck) converter with two integrated N-channel MOSFETs for each channel. It operates using D-CAP2™ control mode. The fast transient response of D-CAP2™ control reduces the required output capacitance to meet a specific level of performance. Proprietary internal circuitry allows the use of low ESR output capacitors including ceramic and special polymer types. DETAILED DESCRIPTION PWM Operation The main control loop of the TPS54495 is an adaptive on-time pulse width modulation (PWM) controller that supports a proprietary D-CAP2™ control mode. D-CAP2™ control combines constant on-time control with an internal compensation circuit for pseudo-fixed frequency and low external component count configuration with both low ESR and ceramic output capacitors. It is stable even with virtually no ripple at the output. At the beginning of each cycle, the high-side MOSFET is turned on. This MOSFET is turned off when the internal timer expires. This timer is set by the converter’s input voltage, VINx, and the output voltage, VOx, to maintain a pseudo-fixed frequency over the input voltage range hence it is called adaptive on-time control. The timer is reset and the high-side MOSFET is turned on again when the feedback voltage falls below the nominal output voltage. An internal ramp is added to the reference voltage to simulate output voltage ripple, eliminating the need for ESR induced output ripple from D-CAP™ control. PWM Frequency and Adaptive On-Time Control TPS54495 uses an adaptive on-time control scheme and does not have a dedicated on board oscillator. The TPS54495 runs with a pseudo-fixed frequency of 700 kHz by using the input voltage and output voltage to set the on-time timer. The on-time is inversely proportional to the input voltage and proportional to the output voltage, therefore, when the duty ratio is VOx/VINx, the frequency is constant. Auto-Skip Eco-Mode™ Control The TPS54495 is designed with Auto-Skip Eco-mode™ to increase light load efficiency. As the output current decreases from heavy load condition, the inductor current also reduces and eventually comes to the point where its ripple valley touches the zero level, which is the boundary between continuous conduction and discontinuous conduction modes. The rectifying MOSFET is turned off when zero inductor current is detected. As the load current further decreases the converter runs into discontinuous conduction mode. The on-time is kept almost the same as it was in the continuous conduction mode because it takes longer to discharge the output capacitor with smaller load current to the nominal output voltage. The transition point to the light load operation IOx(LL) current can be estimated with Equation 1 with 700-kHz used as fSW. (VINx - VOx ) ´ VOx 1 ´ IOx(LL) = 2 ´ L1x ´ fSW VINx (1) Soft Start and Pre-Biased Soft Start The soft start time is adjustable. When the ENx pin becomes high, 8-µA current begins charging the capacitor which is connected from the SSx pin to GND. Smooth control of the output voltage is maintained during start up. The equation for the slow start time is shown in Equation 2. VFBx voltage is 0.765-V and SSx pin source current is 8-µA. C4x(nF) ´ VFBx(V) C4x(nF) ´ 0.765 V TSS (ms) = = ISS (m A) 8 mA (2) The TPS54495 contains a unique circuit to prevent current from being pulled from the output during startup if the output is pre-biased. When the soft-start commands a voltage higher than the pre-bias level (internal soft start becomes greater than internal feedback voltage VFBx), the controller slowly activates synchronous rectification by starting the first low side FET gate driver pulses with a narrow on-time. It then increments that on-time on a cycle-by-cycle basis until it coincides with the time dictated by (1-D), where D is the duty cycle of the converter. This scheme prevents the initial sinking of the pre-biased output, and ensures that the output voltage (VOx) starts and ramps up smoothly into regulation from pre-biased startup to normal mode operation. Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated Product Folder Links: TPS54495 7 TPS54495 SLVSBH0A – JUNE 2012 – REVISED MAY 2013 www.ti.com Current Sensing and Over-Current Protection The output over-current protection (OCP) is implemented using a cycle-by-cycle valley detection control circuit. The switch current is monitored by measuring the low-side FET switch voltage between the SWx and PGNDx pins. This voltage is proportional to the switch current and the on-resistance of the FET. To improve the measurement accuracy, the voltage sensing is temperature compensated. During the on-time of the high-side FET switch, the switch current increases at a linear rate determined by VINx, VOx, the on-time and the output inductor value. During the on-time of the low-side FET switch, this current decreases linearly. The average value of the switch current is the load current IOx. If the sensed voltage on the low-side FET is above the voltage proportional to the current limit, the converter keeps the low-side switch on until the measured voltage falls below the voltage corresponding to the current limit and a new switching cycle begins. In subsequent switching cycles, the on-time is set to the value determined for CCM and the current is monitored in the same manner. Important considerations for this type of over-current protection: The load current is one half of the peak-to-peak inductor current higher than the over-current threshold. Also when the current is being limited, the output voltage tends to fall as the demanded load current may be higher than the current available from the converter. When the over current condition is removed, the output voltage returns to the regulated value. This protection is nonlatching. Undervoltage Protection and Hiccup Mode Hiccup mode of operation protects the power supply from being damaged during an over-current fault condition. If the OCL comparator circuit detects an over-current event the output voltage falls. When the feedback voltage falls below 68% of the reference voltage, the UVP comparator output goes high and an internal UVP delay counter begins counting. After counting UVP delay time, the TPS54495 shuts off the power supply for a given time (7x UVP Enable Delay Time) and then tries to re-start the power supply. If the over-load condition has been removed, the power supply starts and operates normally; otherwise, the TPS54495 detects another over-current event and shuts off the power supply again, repeating the previous cycle. Excess heat due to overload lasts for only a short duration in the hiccup cycle, therefore the junction temperature of the power device is much lower. UVLO Protection Under-voltage lock out protection (UVLO) monitors the voltage of the VREG5 pin. When the VREG5 voltage is lower than the UVLO threshold, the TPS54495 shuts down. As soon as the voltage increases above the UVLO threshold, the converter starts again. Thermal Shutdown TPS54495 monitors its temperature. If the temperature exceeds the threshold value (typically 155°C), the device shuts down. When the temperature falls below the threshold, the IC starts again. When VIN1 starts up and VREG5 output voltage is below its nominal value, the thermal shutdown threshold is lower than 155°C. As long as VIN1 rises, TJ must be kept below 110°C. 8 Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated Product Folder Links: TPS54495 TPS54495 www.ti.com SLVSBH0A – JUNE 2012 – REVISED MAY 2013 TYPICAL CHARACTERISTICS One output is enabled unless otherwise noted. VIN = VIN1 or VIN2. VINx = 12 V, TA = 25°C (unless otherwise noted). EN1, EN2 = ON 1800 Icc − Supply Current (dB) Supply Current−Shutdown Current (µA) 2000 1600 1400 1200 1000 800 600 400 200 VIN1, VIN2 = 12 V 0 −50 0 50 100 Junction Temperature (°C) 150 14 12 10 8 6 4 2 3.40 45 3.38 40 3.36 35 30 25 20 15 10 0 50 100 Junction Temperature (°C) 0 5 10 EN Input Voltage (V) 15 150 G002 VOUT = 3.3 V 3.34 3.32 3.30 3.28 3.26 VIN = 6 V VIN = 12 V VIN = 18 V 3.24 EN1 EN2 5 3.22 3.20 0.0 20 0.5 1.0 1.5 2.0 2.5 Output Current (A) G003 Figure 3. EN Current vs EN Voltage (VEN=12V) 3.0 3.5 4.0 G004 Figure 4. VO1=3.3V Output Voltage vs Output Current 1.55 1.54 VIN1, VIN2 = 12 V 0 −50 Figure 2. Input Shutdown Current vs Junction Temperature Output Voltage (V) EN Input Current (µA) 16 50 0 EN1. EN2 = OFF 18 G001 Figure 1. Input Current vs Junction Temperature 3.40 VOUT = 1.5 V 3.38 3.36 Output Voltage (V) 1.53 Output Voltage (V) 20 1.52 1.51 1.50 1.49 1.48 VIN = 5 V VIN = 12 V VIN = 18 V 1.47 1.46 1.45 0.00 0.25 0.50 0.75 1.00 1.25 Output Current (A) 1.50 1.75 3.34 3.32 3.30 3.28 3.26 3.24 IOUT = 10 mA IOUT = 1 A 3.22 2.00 3.20 0 G005 Figure 5. VO2=1.5V Output Voltage vs Output Current 2 4 6 8 10 12 Input Voltage (V) 14 16 18 20 G006 Figure 6. VO1=3.3V Output Voltage vs Input Voltage Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated Product Folder Links: TPS54495 9 TPS54495 SLVSBH0A – JUNE 2012 – REVISED MAY 2013 www.ti.com TYPICAL CHARACTERISTICS (continued) One output is enabled unless otherwise noted. VIN = VIN1 or VIN2. VINx = 12 V, TA = 25°C (unless otherwise noted). 1.55 1.54 Vout(50mV/div) Output Voltage (V) 1.53 1.52 1.51 1.50 1.49 Iout(2A/div) 1.48 1.47 IOUT = 10 mA IOUT = 1 A 1.46 1.45 0 2 4 6 8 10 12 Input Voltage (V) 14 16 18 20 100 ms/div G007 Figure 7. VO2=1.5V Output Voltage vs Input Voltage Figure 8. VO1=3.3V, 0A to 4A Load Transient Response EN1(10V/div) Vout(50mV/div) Vout(1V/div) Iout(1A/div) SS1(2V/div) 400 ms/div 100 ms/div Figure 9. VO2=1.5V, 0A to 2A Load Transient Response Figure 10. VO1=3.3V, SoftStart 100 90 EN2(10V/div) Efficiency (%) 80 Vout2(0.5V/div) 70 60 50 40 30 VIN = 6 V VIN = 12 V VIN = 18 V 20 10 SS2(2V/div) 0 0.0 0.5 1.0 1.5 2.0 2.5 Output Current (A) 3.0 3.5 4.0 400 ms/div Figure 11. VO2=1.5V, SoftStart 10 G012 Figure 12. VO1=3.3V, Efficiency vs Output Current Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated Product Folder Links: TPS54495 TPS54495 www.ti.com SLVSBH0A – JUNE 2012 – REVISED MAY 2013 TYPICAL CHARACTERISTICS (continued) 100 100 90 90 80 80 70 70 Efficiency (%) Efficiency (%) One output is enabled unless otherwise noted. VIN = VIN1 or VIN2. VINx = 12 V, TA = 25°C (unless otherwise noted). 60 50 40 30 10 0 0.001 40 0.01 0.1 Output Current (A) 1 10 0 0.00 10 750 Switching Frequency (kHz) 90 80 70 60 50 40 30 VIN = 5 V VIN = 12 V VIN = 18 V 20 10 0.1 Output Current (A) 1 500 IOUT1 = 1 A 400 10 0 VOUT1 = 3.3 V 5 10 Input Voltage (V) G015 650 600 550 500 450 20 G016 700 600 500 400 300 200 0 0.01 G017 Figure 17. VO2=1.5V, SW-frequency vs Input Voltage 20 VIN1, VIN2 = 12 V 100 VOUT2 = 1.5 V 15 Figure 16. VO1=3.3V, SW-frequency vs Input Voltage Switching Frequency (kHz) 700 15 G014 550 800 10 Input Voltage (V) 2.00 600 750 5 1.75 650 900 0 1.50 700 800 400 0.75 1.00 1.25 Output Current (A) 450 Figure 15. VO2=1.5V, Light Load Efficiency vs Output Current IOUT2 = 1 A 0.50 Figure 14. VO2=1.5V, Efficiency vs Output Current 800 0.01 0.25 G013 100 0 0.001 VIN = 5 V VIN = 12 V VIN = 18 V 20 Figure 13. VO1=3.3V, Light Load Efficiency vs Output Current Efficiency (%) 50 30 VIN = 6 V VIN = 12 V VIN = 18 V 20 Switching Frequency (kHz) 60 VOUT1 = 3.3 V 0.1 1 Output Current (A) 10 G018 Figure 18. VO1=3.3V, SW-frequency vs Output Current Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated Product Folder Links: TPS54495 11 TPS54495 SLVSBH0A – JUNE 2012 – REVISED MAY 2013 www.ti.com TYPICAL CHARACTERISTICS (continued) One output is enabled unless otherwise noted. VIN = VIN1 or VIN2. VINx = 12 V, TA = 25°C (unless otherwise noted). 900 Switching Frequency (kHz) 800 VIN1, VIN2 = 12 V VO = 3.3 V VO1(10mV/div) 700 600 500 400 SW1(5V/div) 300 200 100 VOUT2 = 1.5 V 0 0.01 0.1 1 Output Current (A) 10 400 nsec/div) G019 Figure 19. VO2=1.5V, SW-frequency vs Output Current Figure 20. VO1=3.3V, VO1 Ripple Voltage (IO1= 4 A) VIN1(50mV/div) VO = 3.3 V VO2(10mV/div) VO = 1.5 V SW2(5V/div) SW1(5V/div) 400 nsec/div) 400 nsec/div) Figure 21. VO2=1.5V, Ripple Voltage (IO2= 2 A) Figure 22. VIN1 Input Voltage Ripple (IO1= 4 A) VO = 1.5 V VIN2(50mV/div) SW2(5V/div) 400 nsec/div) Figure 23. VIN2 Input Voltage Ripple (IO2= 2 A) 12 Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated Product Folder Links: TPS54495 TPS54495 www.ti.com SLVSBH0A – JUNE 2012 – REVISED MAY 2013 DESIGN GUIDE Step By Step Design Procedure To • • • begin the design process, you must know a few application parameters: Input voltage range Output voltage Output current In all formulas x is used to indicate that they are valid for both converters. For the calculations the estimated switching frequency of 700 kHz is used. VINx 12V ± 10% C11 10 mF VO1 3.3 V L11 2.2 mH C31 0.1 mF C21 22 mF x2 1 VIN1 2 VBST1 3 4 VIN2 VBST2 15 PGND C12 10 mF SW2 14 TPS54495 HTSSOP16 VO2 1.5 V C22 22 mF x2 PGND2 13 PGND 5 EN1 EN2 12 6 SS1 SS2 11 7 VFB1 VFB2 10 8 GND VREG5 9 C41 R11 73.2 kW L12 1.5 mH C32 0.1 mF SW1 PGND1 16 C42 SGND SGND R21 22.1 kW C5 1uF R12 21.5 kW R22 22.1 kW PGND SGND SGND Figure 24. Schematic Diagram for the Design Example Output Voltage Resistors Selection The output voltage is set with a resistor divider from the output node to the VFBx pin. It is recommended to use 1% tolerance or better divider resistors. Start by using Equation 3 to calculate VOx. To improve the efficiency at very light loads consider using larger value resistors, but too high resistance values will be more susceptible to noise and voltage errors due to the VFBx input current will be more noticeable. æ R1x ö VOx = 0.765 V ´ ç 1+ ÷ è R2x ø (3) Output Filter Selection The output filter used with the TPS54495 is an LC circuit. This LC filter has double pole at: 1 FP = 2p L1x ´ C1x Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated Product Folder Links: TPS54495 (4) 13 TPS54495 SLVSBH0A – JUNE 2012 – REVISED MAY 2013 www.ti.com At low frequencies, the overall loop gain is set by the output set-point resistor divider network and the internal gain of the TPS545495. The low frequency phase is 180 degrees. At the output filter pole frequency, the gain rolls off at a –40 dB per decade rate and the phase drops rapidly. D-CAP2™ introduces a high frequency zero that reduces the gain roll off to –20 dB per decade and increases the phase to 90 degrees one decade above the zero frequency. The inductor and capacitor selected for the output filter must be selected so that the double pole of Equation 4 is located below the high frequency zero but close enough that the phase boost provided by the high frequency zero provides adequate phase margin for a stable circuit. To meet this requirement use the values recommended in Table 1. Table 1. Recommended Component Values Cffx (pF) (1) Output Voltage (V) R1x (kΩ) R2x (kΩ) L1x (µH) C2x (µF) 1 6.81 22.1 1.5 - 2.2 20 - 68 1.05 8.25 22.1 1.5 - 2.2 20 - 68 1.2 12.7 22.1 1.5 - 2.2 20 - 68 1.5 21.5 22.1 1.5 - 2.2 20 - 68 1.8 30.1 22.1 5 - 22 2.2 - 3.3 20 - 68 2.5 49.9 22.1 5 - 22 2.2 - 3.3 20 - 68 3.3 73.2 22.1 5 - 22 2.2 - 3.3 20 - 68 5 124 22.1 5 - 22 4.7 20 - 68 6.5 165 22.1 5 - 22 4.7 20 - 68 (1) Optional For higher output voltages at or above 1.8 V, additional phase boost can be achieved by adding a feed forward capacitor (Cffx) in parallel with R1x. The inductor peak-to-peak ripple current, peak current and RMS current are calculated using Equation 5, Equation 6 and Equation 7. The inductor saturation current rating must be greater than the calculated peak current and the RMS or heating current rating must be greater than the calculated RMS current. For the calculations, use 700 kHz as the switching frequency, fSW. Make sure the chosen inductor is rated for the peak current of Equation 6 and the RMS current of Equation 7. VINx(MAX) - VOx VOx ´ ΔIL1x = VINx(MAX) L1x ´ fSW (5) IL1xpeak = IOx ΔI + L1x 2 IL1x(RMS) = IOx 2 + (6) 1 DIL1x 2 12 (7) For the above design example, the calculated peak current is 4.46 A and the calculated RMS current is 4.01 A for VO2. The inductor used is a TDK CLF7045T-2R2N with a rated current of 5.5A based on the inductance change, and of 4.3A based on the temperature rise. The capacitor value and ESR determines the amount of output voltage ripple. The TPS54495 is intended for use with ceramic or other low ESR capacitors. The recommended value range is from 20µF to 68µF. Use Equation 8 to determine the required RMS current rating for the output capacitor(s). VOx ´ (VINx - VOx ) IC2x(RMS) = 12 ´ VINx ´ L1x ´ fSW (8) For this design two TDK C3216X5R0J226M 22µF output capacitors are used. The typical ESR is 2 mΩ each. The calculated RMS current is 0.19A and each output capacitor is rated for 4A. 14 Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated Product Folder Links: TPS54495 TPS54495 www.ti.com SLVSBH0A – JUNE 2012 – REVISED MAY 2013 Input Capacitor Selection The TPS54495 requires an input decoupling capacitor and a bulk capacitor is needed depending on the application. A ceramic capacitor of or above 10µF is recommended for the decoupling capacitor. Additionally, 0.1 µF ceramic capacitors from pin 1 and Pin 16 to ground are recommended to improve the stability and reduce the SWx node overshoots. The capacitors voltage rating needs to be greater than the maximum input voltage. Bootstrap Capacitor Selection A 0.1 µF ceramic capacitors must be connected between the VBSTx and SWx pins for proper operation. It is recommended to use ceramic capacitors with a dielectric of X5R or better. VREG5 Capacitor Selection A 1 µF ceramic capacitor must be connected between the VREG5 and GND pins for proper operation. It is recommended to use a ceramic capacitor with a dielectric of X5R or better. Thermal Information This 16-pin PWP package incorporates an exposed thermal pad. The thermal pad must be soldered directly to the printed circuit board (PCB). After soldering, the PCB is used as a heatsink. In addition, through the use of thermal vias, the thermal pad can be attached directly to the appropriate copper plane shown in the electrical schematic for the device, or alternatively, can be attached to a special heatsink structure designed into the PCB. This design optimizes the heat transfer from the integrated circuit (IC). For additional information on the exposed thermal pad and how to use the advantage of its heat dissipating abilities, refer to the Technical Brief, PowerPAD™ Thermally Enhanced Package, Texas Instruments Literature No. SLMA002 and Application Brief, PowerPAD™ Made Easy, Texas Instruments Literature No. SLMA004. The exposed thermal pad dimensions for this package are shown in the following illustration. Figure 25. Thermal Pad Dimensions Layout Considerations 1. Keep the input current loop as small as possible. And avoid the input switching current through the thermal pad. 2. Keep the SW node as physically small and short as possible to minimize parasitic capacitance and inductance and to minimize radiated emissions. 3. Keep analog and non-switching components away from switching components. 4. Make a single point connection from the signal ground to power ground. 5. Do not allow switching currents to flow under the device. 6. Keep the pattern lines for VINx and PGNDx broad. Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated Product Folder Links: TPS54495 15 TPS54495 SLVSBH0A – JUNE 2012 – REVISED MAY 2013 www.ti.com 7. Exposed pad of device must be soldered to PGND. 8. VREG5 capacitor should be placed near the device, and connected to GND. 9. Output capacitors should be connected with a broad pattern to the PGND. 10. Voltage feedback loops should be as short as possible, and preferably with ground shields. 11. Kelvin connections should be brought from the output to the feedback pin of the device. 12. Providing sufficient vias is preferable for VIN, SW and PGND connections. 13. PCB pattern for VIN, SW, and PGND should be as broad as possible. 14. VIN Capacitor should be placed as near as possible to the device. VIN2 VIN HIGH FREQUENCY BYPASS CAPACITOR ~0.1µF VIN1 1 16 VIN2 VBST 1 2 15 VBST2 SW 1 3 14 SW2 4 13 PGND 2 EN1 5 12 EN2 SS1 6 11 SS2 VFB1 7 10 VFB2 GND 8 9 PGND 1 Symmetrical Layout for CH1 and CH2 VIN INPUT BYPASS CAPACITOR 10µF x2 Switching noise flows through IC and CIN . It avoids the thermal Pad. OUTPUT FILTER CAPACITOR VO2 OUTPUT INDUCTOR Recommend to keep distance more than 3-4mm. (to avoid noise scattering, especially GND plane.) TO ENABLE CONTROL Keep distance more than 1 inch VREG 5 POWER GND To feedback resisters Feedback resisters BIAS CAP GND PLANE 2,3 or bottom layer Via to GND Plane - Blue parts can be placed on the bottom side - Connect the SWx pins through another layer with the inductor (yellow line) Figure 26. TPS54495 PWP Package Layout 16 Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated Product Folder Links: TPS54495 TPS54495 www.ti.com SLVSBH0A – JUNE 2012 – REVISED MAY 2013 VOUT2 KEEP VIAS > 3-4 mm FROM OUTPUT CAPACITORS OUTPUT2 FILTER CAPACITORS POWER GROUND OUTPUT2 INDUCTOR KEEP OUTPUT VIAS > 25 mm FROM INPUT VIAS TO ENABLE CONTROL VIN INPUT BYPASS CAPACITORS PG2 16 15 14 13 TO POWER GOOD PULL UP 2 FEEDBACK RESISTORS EXPOSED THERMAL PAD AREA 11 VREG5 VIN1 3 10 GND VBST1 4 9 VFB1 BOOST CAPACITOR VIN HIGH FREQUENCY BYPASS CAPACITOR 5 6 7 8 PG1 2 VIN2 EN 1 VFB2 1 PGND1 12 VBST2 SW1 VIN EN2 BOOST CAPACITOR PGND2 VIN HIGH FREQUENCY BYPASS CAPACITOR SW2 KEEP VIAS > 3-4 mm FROM INPUT CAPACITORS BIAS ANALOG CAP GROUND TRACE FEEDBACK RESISTORS TO POWER GOOD PULL UP 1 KEEP VIAS > 3-4 mm FROM INPUT CAPACITORS VIA to Internal or Bottom Layer Ground Plane VIN INPUT BYPASS CAPACITORS TO ENABLE CONTROL VIA to internal or Bottom Layer Etch OUTPUT1 INDUCTOR Etch or Copper Fill on Top Layer KEEP OUTPUT VIAS > 25 mm FROM INPUT VIAS POWER GROUND Internal or Bottom Layer Ground Plane Etch on Bottom Layer, Internal Layer or Under Component OUTPUT1 FILTER CAPACITORS VOUT1 NOTE: IT IS POSSIBLE TO PLACE SOME COMPONENTS SUCH AS BOOST CAPACITOR AND FEEDBACK RESISTORS ON BOTTOM LAYER KEEP VIAS > 3-4 mm FROM OUTPUT CAPACITORS INTERNAL OR BOTTOM LAYER GROUND PLANE Figure 27. RSA Package Layout Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated Product Folder Links: TPS54495 17 TPS54495 SLVSBH0A – JUNE 2012 – REVISED MAY 2013 www.ti.com REVISION HISTORY Changes from Original (June 2012) to Revision A Page • Added 16-pin VQFN package to the Features and Description ........................................................................................... 1 • Added the RSA 16 pin package to the Ordering Information table ...................................................................................... 2 • Added the RSA package to the Thermal Information table .................................................................................................. 2 • Added the RSA 16 pin package pinout image, pin names and functions to the DEVICE INFORMATION section ............. 5 • Added Figure 27 ................................................................................................................................................................. 17 18 Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated Product Folder Links: TPS54495 PACKAGE OPTION ADDENDUM www.ti.com 10-Dec-2020 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) (4/5) (6) TPS54495PWP ACTIVE HTSSOP PWP 16 90 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 85 PS54495 TPS54495PWPR ACTIVE HTSSOP PWP 16 2000 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 85 PS54495 TPS54495RSAR ACTIVE QFN RSA 16 3000 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 85 TPS 54495 TPS54495RSAT ACTIVE QFN RSA 16 250 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 85 TPS 54495 (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) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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