TPS53128 www.ti.com SLVSAE4 – JULY 2010 DUAL SYNCHRONOUS STEP-DOWN CONTROLLER FOR LOW VOLTAGE POWER RAILS Check for Samples: TPS53128 FEATURES 1 • 2 • • • • • • • • D-CAP2™ Mode Control – Fast Transient Response – No External Parts Required for Loop Compensation – Compatible With Ceramic Output Capacitors High Initial Reference Accuracy (±1%) Low Output Ripple Wide Input Voltage Range: 4.5 V to 24 V Output Voltage Range: 0.76 V to 5.5 V Low-Side RDS(ON) Loss-Less Current Sensing Adaptive Gate Drivers with Integrated Boost Diode Adjustable Soft Start Non-Sinking Pre-Biased Soft Start • • • • 350-kHz Switching Frequency Cycle-by-Cycle Over-Current Limiting Control 30-mV to 300-mV OCP Threshold Voltage Thermally Compensated OCP by 4000 ppm/°C at ITRIP APPLICATIONS • 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 DESCRIPTION The TPS53128 is a dual, adaptive on-time D-CAP2™ mode synchronous buck controller. The part enables system designers to cost effectively complete the suite of various end equipment's power bus regulators with a low external component count and low standby consumption. The main control loop for the TPS53128 uses the D-CAP2™ Mode topology which provides a very fast transient response with no external component. The TPS53128 also has a proprietary circuit that enables the device to adapt not only low equivalent series resistance (ESR) output capacitors such as POSCAP/SP-CAP, but also ceramic capacitor. The fixed frequency emulated adaptive on-time control supports seamless operation between PWM mode at heavy load condition and reduced frequency operation at light load for high efficiency down to milliampere range. The part provides a convenient and efficient operation with conversion voltages from 4.5 V to 24 V and output voltage from 0.76 V to 5.5 V. The TPS53128 is available in 4-mm x 4-mm 24 pin QFN (RGE) or 24 pin TSSOP (PW) packages, and is specified from -40°C to 85°C ambient temperature range. 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 is a trademark 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 © 2010, Texas Instruments Incorporated TPS53128 SLVSAE4 – JULY 2010 www.ti.com TYPICAL APPLICATION CIRCUITS Input Voltage 4.5V to 24V C9 10uF C10 4700pF R5 10kΩ C6 10uF VO2 1.05V/4A Q3 FDS8878 L2 SPM6530T 1.5uH C5 0.1uF VBST2 9 DRVH2 10 SW2 3 2 1 VFB1 VO1 VFB2 EN2 8 4 SS1 5 GND 6 7 SGND R1 13kΩ R2 10kΩ VO2 R4 3.52kΩ PGND EN1 24 Power PAD Q1 FDS8878 L1 SPM6530T 1.5uH C2 0.1uF VBST1 23 DRVH1 22 TPS53128 RGE SW1 21 L1 Q2 FDS8690 C3 10uF VO1 1.8V/4A (QFN ) PGND1 19 C4 22uFx4 PGND 13 R6 4.3kΩ TRIP1 PGND2 VIN 12 VREG5 DRVL1 20 SS2 DRVL2 V5FILT 11 TRIP2 Q4 FDS8690 14 15 16 17 18 C7 4.7uF C８ 1uF C1 22uFx4 R３ 3.3kΩ PGND PGND C11 4700pF SGND Figure 1. QFN Q1 FDS8878 L1 SPM6530T 1.5uH C2 0.1uF 1 R1 13kΩ R2 10kΩ R5 10kΩ R4 3.52kΩ SW1 EN1 PGND1 22 4 VO1 TRIP1 21 VIN 20 6 GND 7 SS1 8 VFB2 Q2 FDS8690 DRVL1 23 VBST1 3 VFB1 VO1 1.8V/4A 24 2 5 C10 SGND4700pF DRVH1 TPS53128PW TSSOP24 C3 10uF C1 22uFx4 R３ 3.3kΩ PGND Input Voltage VREG5 19 V5FILT 18 SS2 17 9 VO2 TRIP2 16 10 EN2 PGND2 15 11 VBST2 DRVL2 14 12 DRVH2 SW2 13 C7 4.7uF 4.5V to 24V C9 10uF C８ 1uF PGND C11 4700pF R6 4.3kΩ SGND PGND Q4 FDS8690 C5 0.1uF L2 SPM6530T 1.5uH Q3 FDS8878 C4 22uFx4 C6 10uF VO2 1.05V/4A Figure 2. TSSOP 2 Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 TPS53128 www.ti.com SLVSAE4 – JULY 2010 ORDERING INFORMATION (1) PACKAGE (2) TA ORDERING PART NUMBER (3) 24 TPS53128PWR TSSOP ECO PLAN Tape-and-Reel TPS53128RGER –40°C to 85°C (2) (3) OUTPUT SUPPLY TPS53128RGET Plastic Quad Flat Pack (QFN) (1) PINS Tape-and-Reel Green (RoHS and no Sb/Br) Tape-and-Reel TPS53128PW Tube 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) VALUE VI Input voltage range VO Output voltage range UNIT VIN, EN1, EN2 –0.3 to 26 VBST1, VBST2 –0.3 to 32 VBST1 - SW1, VBST2 - SW2 –0.3 to 6 V5FILT, VFB1, VFB2, TRIP1, TRIP2, VO1, VO2 –0.3 to 6 SW1, SW2 –2 to 26 DRVH1, DRVH2 –1 to 32 DRVH1 - SW1, DRVH2 - SW2 –0.3 to 6 DRVL1, DRVL2, VREG5, SS1, SS2 –0.3 to 6 PGND1, PGND2 V V –0.3 to 0.3 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) 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. DISSIPATION RATINGS 2-oz. trace and copper pad with solder TA < 25°C POWER RATING DERATING FACTOR ABOVE TA = 25°C TA = 85°C POWER RATING 24-pin QFN 2.33 W 23.3 mW/°C 0.93 W 24-pin TSSOP 0.778 W 7.8 mW/°C 0.31 W PACKAGE RECOMMENDED OPERATING CONDITIONS over operating free-air temperature range (unless otherwise noted) VIN VI Supply input voltage Input voltage MIN MAX VIN 4.5 24 V5FILT 4.5 5.5 VBST1, VBST2 –0.1 30 VBST1 - SW1, VBST2 - SW2 –0.1 5.5 VFB1, VFB2, VO1, VO2 –0.1 5.5 TRIP1, TRIP2 –0.1 0.3 EN1, EN2 –0.1 24 SW1, SW2 –1.8 24 UNIT Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 V V 3 TPS53128 SLVSAE4 – JULY 2010 www.ti.com RECOMMENDED OPERATING CONDITIONS (continued) over operating free-air temperature range (unless otherwise noted) MIN VO Output voltage MAX DRVH1, DRVH2 –0.1 30 VBST1 - SW1, VBST2 - SW2 –0.1 5.5 DRVL1, DRVL2, VREG5, SS1, SS2 –0.1 5.5 PGND1, PGND2 –0.1 0.1 UNIT V TA Operating free-air temperature –40 85 °C TJ Operating junction temperature –40 125 °C TYP MAX UNIT 450 800 mA 30 60 mA 1 % ELECTRICAL CHARACTERISTICS over operating free-air temperature range (unless otherwise noted) PARAMETER TEST CONDITIONS MIN SUPPLY CURRENT IIN VIN supply current VIN current, TA = 25°C, VREG5 tied to V5FILT, EN1 = EN2 = 5 V, VFB1 = VFB2 = 0.8 V, SW1 = SW2 = 0.5 V IVINSDN VIN shutdown current VIN current, TA = 25°C, no load , EN1 = EN2 = 0 V, VREG5 = ON VFB VOLTAGE AND DISCHARGE RESISTANCE VBG Bandgap initial regulation accuracy TA = 25°C TA = 25°C, SWinj = OFF VVFBTHx VFBx threshold voltage TA = 0°C to 70°C, SWinj = OFF (1) TA = -40°C to 85°C, SWinj = OFF (1) IVFB VFB input current VFBx = 0.8 V, TA = 25°C RDischg VO discharge resistance ENx = 0 V, VOx = 0.5 V, TA = 25°C –1 755 765 775 753.5 776.5 752 778 –100 mV –10 100 nA 40 80 Ω 5.0 5.2 V VREG5 OUTPUT VVREG5 VREG5 output voltage TA = 25°C, 5.5 V < VIN < 24 V, 0 < IVREG5 < 10 mA VLN5 Line regulation 5.5 V < VIN < 24 V, IVREG5 = 10 mA 20 mV VLD5 Load regulation 1 mA < IVREG5 < 10 mA 40 mV Output current VIN = 5.5 V, VREG5 = 4.0 V, TA = 25°C IVREG5 4.8 170 mA OUTPUT: N-CHANNEL MOSFET GATE DRIVERS RDRVH DRVH resistance RDRVL DRVL resistance TD Dead time Source, IDRVHx = –100 mA 5.5 11 Sink, IDRVHx = 100 mA 2.5 5 Source, IDRVLx = –100 mA 4 8 Sink, IDRVLx = 100 mA 2 4 Ω Ω DRVHx-low to DRVLx-on 20 50 80 DRVLx-low to DRVHx-on 20 40 80 Forward voltage VVREG5-VBSTx, IF = 10 mA, TA = 25°C 0.7 0.8 0.9 V VBST leakage current VBSTx = 29 V, SWx = 24 V, TA = 25°C 0.1 1 mA ns INTERNAL BOOST DIODE VFBST IVBSTLK ON-TIME TIMER CONTROL TON1L CH1 on time SW1 = 12 V, VO1 = 1.8 V 490 ns TON2L CH2 on time SW2 = 12 V, VO2 = 1.8 V 390 ns (1) 4 Not production tested - ensured by design. Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 TPS53128 www.ti.com SLVSAE4 – JULY 2010 ELECTRICAL CHARACTERISTICS (continued) over operating free-air temperature range (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT TOFF1L CH1 min off time SW1 = 0.7 V, TA = 25°C, VFB1 = 0.7 V 285 ns TOFF2L CH2 min off time SW2 = 0.7 V, TA = 25°C, VFB2 = 0.7 V 285 ns SOFT START ISSC SS1/SS2 charge current VSS1/VSS2 = 0 V, TA = 25°C TCISSC ISSC temperature coefficient On the basis of 25°C (1) –1.5 –2 ISSD SS1/SS2 discharge current VSS1/VSS2 = 0.5 V 100 150 Wake up 3.7 4.0 4.3 Hysteresis 0.2 0.3 0.4 2.0 –4 –2.5 3 mA nA/°C mA UVLO VUV5VFILT V5FILT UVLO threshold V LOGIC THRESHOLD VENH ENx high-level input voltage EN 1/2 VENL ENx low-level input voltage EN 1/2 V 0.3 V CURRENT SENSE ITRIP TRIP source current VTRIPx = 0.1 V, TA = 25°C TCITRIP ITRIP temperature coefficient On the basis of 25°C VOCLoff OCP compensation offset VRtrip Current limit threshold setting range 8.5 10 11.5 4000 mA ppm/°C (VTRIPx-GND-VPGNDx-SWx) voltage, VTRIPx-GND = 60 mV, TA = 25°C –15 (VTRIPx-GND-VPGNDx-SWx) voltage, VTRIPx-GND = 60 mV –20 20 30 300 mV 120 % VTRIPx-GND voltage 0 15 mV OUTPUT UNDERVOLTAGE AND OVERVOLTAGE PROTECTION VOVP Output OVP trip threshold TOVPDEL Output OVP prop delay VUVP Output UVP trip threshold TUVPDEL Output UVP delay TUVPEN Output UVP enable delay OVP detect 110 UVP detect 65 115 1.5 Hysteresis (recover < 20 ms) UVP enable delay / soft-start time 70 ms 75 10 % 17 30 40 ms x1.4 x1.7 x2.0 ms THERMAL SHUTDOWN TSDN (2) Thermal shutdown threshold Shutdown temperature Hysteresis (2) (2) 150 20 °C Not production tested - ensured by design. TERMINAL FUNCTIONS PIN Fucntion Table TERMINAL NAME QFN 24 TSSOP 24 I/O DESCRIPTION VBST1, VBST2 23, 8 2, 11 I Supply input for high-side NFET driver. Bypass to SWx with a high-quality 0.1-mF ceramic capacitor. An external schottky diode can be added from VREG5 if forward drop is critical to drive the high-side FET. EN1, EN2 24, 7 3, 10 I Enable. Pull High to enable SMPS. VO1, VO2 1, 6 4, 9 I Output voltage inputs for on-time adjustment and output discharge. Connect directly to the output voltage. VFB1, VFB2 2, 5 5, 8 I D-CAP2 feedback inputs. Connect to output voltage with resistor divider. Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 5 TPS53128 SLVSAE4 – JULY 2010 www.ti.com PIN Fucntion Table (continued) TERMINAL QFN 24 TSSOP 24 I/O 3 6 I Signal ground pin. Connect to PGND1, PGND2 and system ground at a single point. DRVH1, DRVH2 22, 9 1, 12 O High-side N-Channel MOSFET gate driver outputs. SWx referenced drivers switch between SWx (OFF) and VBSTx (ON). SW1, SW2 21, 10 24, 13 I/O Switch node connections for both the high-side drivers and the over current comparators. DRVL1, DRVL2 20, 11 23, 14 O Low-side N-Channel MOSFET gate driver outputs. PGND referenced drivers switch between PGNDx (OFF) and VREG5 (ON). PGND1, PGND2 19, 12 22, 15 I/O Power ground connections for both the low-side drivers and the over current comparators. Connect PGND1, PGND2 and GND strongly together near the IC. TRIP1, TRIP2 18, 13 21, 16 I Over current threshold programming pin. Connect to GND with a resistor to GND to set threshold for low-side RDS(ON) current limit. VIN 17 20 I Supply Input for 5-V linear regulator. Bypass to GND with a minimum high-quality 0.1-mF ceramic capacitor. V5FILT 15 18 I 5-V supply input for the entire control circuitry except the MOSFET drivers. Bypass to GND with a minimum high-quality 1.0-mF ceramic capacitor. V5FILT is connected to VREG5 via an internal 10-Ω resistor. VREG5 16 19 O Output of 5-V linear regulator and supply for MOSFET drivers. Bypass to GND with a minimum high-quality 4.7-mF ceramic capacitor. VREG5 is connected to V5FILT via an internal 10-Ω resistor. 4,14 7, 17 O Soft-start programming pin. Connect capacitor from SSx pin to GND to program soft-start time. NAME GND SS1, SS2 DESCRIPTION xxx xxx TSSOP PACKAGE (TOP VIEW) 6 PGND1 DRVH1 VBST1 EN1 VO1 VFB1 GND 19 DRVL1 20 SW1 21 DRVH1 22 VBST1 23 24 EN1 QFN PACKAGE (TOP VIEW) SS1 4 15 V5 FILT VFB2 5 14 SS 2 EN2 VBST2 VO2 6 13 TRIP2 DRVH2 12 VREG5 11 16 DRVL2 3 PGND2 GND 10 VIN SW2 17 9 2 DRVH2 VFB1 8 TRIP1 VBST2 18 7 1 EN2 VO1 SS1 VFB2 VO2 Submit Documentation Feedback 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 14 13 SW1 DRVL1 PGND1 TRIP1 VIN VREG5 V5FILT SS2 TRIP2 PGND2 DRVL2 SW2 Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 TPS53128 www.ti.com SLVSAE4 – JULY 2010 FUNCTIONAL BLOCK DIAGRAM SS2 SW2 SS1 SW1 Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 7 TPS53128 SLVSAE4 – JULY 2010 www.ti.com ERR COMP SWX 8 Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 TPS53128 www.ti.com SLVSAE4 – JULY 2010 DETAILED DESCRIPTION PWM Operation The main control loop of the TPS53128 is an adaptive on-time pulse width modulation (PWM) controller using a proprietary D-CAP2™ mode control. D-CAP2™ mode 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 synchronous high-side MOSFET is turned on. After an internal one-shot timer expires, this MOSFET is turned off. When the feedback voltage falls below the reference voltage, the one-shot timer is reset and the high-side MOSFET is turned back on. The one shot is set by the converter input voltage VIN, and the output voltage VO, to maintain a pseudo-fixed frequency over the input voltage range. An internal ramp is added to the reference voltage to simulate output ripple, eliminating the need for ESR induced output ripple from D-CAP mode control. Light-Load Condition TPS53128 automatically reduces switching frequency at light-load conditions to maintain high efficiency. This reduction of frequency is achieved smoothly and without increase of VOUT ripple or load regulation. Detail operation is described as follows. As the output current decreases from heavy-load condition, the inductor current is also reduced, and eventually comes to the point that its valley touches zero current, which is the boundary between continuous conduction and discontinuous condition modes. The low-side MOSFET is turned off when this zero inductor current is detected. As the load current is further decreased, the converter runs in discontinuous conduction mode and it takes longer and longer to discharge the output capacitor to the level that requires the next ON cycle. The ON time is kept the same as that in the heavy-load condition. In reverse, when the output current increases from light load to heavy load, the switching frequency increases to the preset value as the inductor current reaches the continuous conduction. The transition load point to the light load operation, IOUT(LL) (i.e., threshold between continuous and discontinuous condition mode) can be calculated as follows. 1 I OUT ( LL ) = 2 ´ L ´ fsw VIN - Vox ´ Vox VIN (1) Where fSW is the PWM switching frequency. Switching frequency versus output current in the light-load condition is a function of L, fSW, VIN and VOUT, but it decreases almost proportional to the output current from the IOUT(LL) given in Equation 1. Drivers Each channel of the TPS53128 contains two high-current resistive MOSFET gate drivers. The low-side driver is a PGND referenced, VREG5 powered driver designed to drive the gate of a high-current, low RDS(ON) N-channel MOSFET whose source is connected to PGND. The high-side driver is a floating SWx referenced VBST powered driver designed to drive the gate of a high-current, low RDS(ON) N-channel MOSFET. To maintain the VBST voltage during the high-side driver ON time, a capacitor is placed from SWx to VBSTx. Each driver draws average current equal to gate charge (Qg at Vgs = 5 V) times switching frequency (fSW). To prevent cross-conduction, there is a narrow dead-time when both high-side and low-side drivers are OFF between each driver transition. During this time the inductor current is carried by one of the MOSFETs body diodes. PWM Frequency and Adaptive On-Time Control TPS53128 employs adaptive on-time control scheme and does not have a dedicated on board oscillator. TPS53128 runs with pseudo-constant frequency by using the input voltage and output voltage to set the on-time one-shot timer. The on-time is inversely proportional to the input voltage and proportional to the output voltage. Therefore, when the duty ratio is VOUT/VIN, the frequency is constant. Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 9 TPS53128 SLVSAE4 – JULY 2010 www.ti.com 5-Volt Regulator The TPS53128 has an internal 5-V low-dropout (LDO) regulator to provide a regulated voltage for all both drivers and the IC's internal logic. A high-quality 4.7-mF or greater ceramic capacitor from VREG5 to GND is required to stabilize the internal regulator. An internal 10-Ω resistor from VREG5 filters the regulator output to the IC's analog and logic input voltage, V5FILT. An additional high-quality 1.0-mF ceramic capacitor is required from V5FILT to GND to filter switching noise from VREG5. Soft Start The TPS53128 has a programmable soft-start . When the ENx pin becomes high, 2.0-mA current begins charging the capacitor connected from the SS pin to GND. The internal reference for the D-CAP2™ mode control comparator is overridden by the soft-start voltage until the soft-start voltage is greater than the internal reference for smooth control of the output voltage during start up. Pre-Bias Support The TPS53128 supports pre-bias start-up without sinking current from the output capacitor. When enabled, the low-side driver is held off until the soft-start commands a voltage higher than the pre-bias level (internal soft-start becomes greater than feedback voltage (VFB)), then the TPS53128 slowly activates synchronous rectification by limiting the first DRVL pulses with a narrow on-time. This limited on-time is then incremented on a cycle-by-cycle basis until it coincides with the full 1-D off-time. This scheme prevents the initial sinking of current from the pre-bias output, and ensure that the output voltage (VOUT) starts and ramps up smoothly into regulation and the control loop is given time to transition from pre-biased start-up to normal mode operation. Output Discharge Control TPS53128 discharges the outputs when ENx is low, or the controller is turned off by the protection functions (OVP, UVP, UVLO, and thermal shutdown). The device discharges output using an internal 40-Ω MOSFET which is connected to VOx and PGNDx. The external low-side MOSFET is not turned on during the output discharge operation to avoid the possibility of causing negative voltage at the output. This discharge ensures that on start the regulated voltage always initializes from 0 V. Over Current Limit TPS53128 has cycle-by-cycle over current limit feature. The over current limits the inductor valley current by monitoring the voltage drop across the low-side MOSFET RDS(ON) during the low-side driver on-time. If the inductor current is larger than the over current limit (OCL), the TPS53128 delays the start of the next switching cycle until the sensed inductor current falls below the OCL current. MOSFET RDS(ON) current sensing is used to provide an accuracy and cost effective solution without external devices. To program the OCL, the TRIP pin should be connected to GND through a trip voltage setting resistor, according to the following equations. ( ) (VIN - VO) VO VTRIP = IOCL - ¾ · ¾ 2 · L1 · fSW VIN · RDS(ON) (2) VTRIP (mV) RTRIP (kW) = ¾ ITRIP (mA) (3) The trip voltage should be between 30 mV to 300 mV over all operational temperature, including the 4000-ppm/°C temperature slope compensation for the temperature dependency of the RDS(ON). If the load current exceeds the over current limit, the voltage will begin to drop. If the over current conditions continues the output voltage will fall below the under voltage protection threshold and the TPS53128 will shut down. In an over current condition, the current to the load exceeds the current to the output capacitor; thus the output voltage tends to fall off. Eventually, it will end up with crossing the under voltage protection threshold and shutdown. 10 Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 TPS53128 www.ti.com SLVSAE4 – JULY 2010 Over/Under Voltage Protection TPS53128 monitors a resistor divided feedback voltage to detect over and under voltage. If the feedback voltage is higher than 115% of the reference voltage, the OVP comparator output goes high and the circuit latches the high-side MOSFET driver OFF and the low-side MOSFET driver ON. When the feedback voltage is lower than 70% of the reference voltage, the UVP comparator output goes high and an internal UVP delay counter begins counting. After 30 ms, TPS53128 latches OFF both top and bottom MOSFET drivers. This function is enabled approximately 1.7 x TSS after power-on. The OVP and UVP latch off is reset when EN goes low level. UVLO Protection TPS53128 has V5FILT under voltage lock out protection (UVLO) that monitors the voltage of V5FILT pin. When the V5FILT voltage is lower than UVLO threshold voltage, the device is shut off. All output drivers are OFF and output discharge is ON. The UVLO is non-latch protection. Thermal Shutdown The TPS53128 includes an over temperature protection shut-down feature. If the TPS53128 die temperature exceeds the OTP threshold (typically 150°C), both the high-side and low-side drivers are shut off, the output voltage discharge function is enabled and then the device is shut off until the die temperature drops. Thermal shutdown is a non-latch protection. Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 11 TPS53128 SLVSAE4 – JULY 2010 www.ti.com TYPICAL CHARACTERISTICS VIN SHUTDOWN CURRENT vs JUNCTION TEMPERATURE 700 60 600 50 -m IIN - Supply Current - mA VIN SUPPLY CURRENT vs JUNCTION TEMPERATURE 500 40 400 30 300 20 200 10 VREG5=ON 100 0 0 -50 0 50 100 -50 150 0 50 100 150 TJ - Junction Temperature - °C Figure 3. Figure 4. TRIP SOURCE CURRENT vs JUNCTION TEMPERATURE VREG5 VOLTAGE vs JUNCTION TEMPERATURE 5.070 IT R IP - S o u r c e C u r r e n t - m A 5.060 VFB Voltage - V 5.050 5.040 5.030 5.020 5.010 5.000 -50 TJ - Junction Temperature - °C Figure 5. 12 0 50 100 150 TJ - Junction Temperature - °C Figure 6. Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 TPS53128 www.ti.com SLVSAE4 – JULY 2010 TYPICAL CHARACTERISTICS (continued) VREG5 VOLTAGE vs INPUT VOLTAGE VFB1 VOLTAGE vs INPUT VOLTAGE 5.500 0.800 0.795 0.790 VFB1 Voltage - V VREG5 Voltage - V 5.300 5.100 4.900 0.785 0.780 0.775 0.770 0.765 4.700 0.760 0.755 4.500 0 5 10 15 20 25 0.750 VIN - Input Voltage - V 0 5 10 15 20 25 VIN - Input Voltage - V Figure 7. Figure 8. VFB2 VOLTAGE vs INPUT VOLTAGE VFB1 VOLTAGE vs JUNCTION TEMPERATURE 0.800 0.795 0.785 VFB1 Voltage - V VFB1 Voltage - V 0.790 0.780 0.775 0.770 0.765 0.760 0.755 0.750 0 5 10 15 VIN - Input Voltage - V 20 25 0.800 0.795 0.790 0.785 0.780 0.775 0.770 0.765 0.760 0.755 0.750 -50 0 50 100 150 TJ - Junction Temperature - °C Figure 9. Figure 10. Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 13 TPS53128 SLVSAE4 – JULY 2010 www.ti.com TYPICAL CHARACTERISTICS (continued) VFB2 VOLTAGE vs JUNCTION TEMPERATURE 0.800 0.795 VFB2 Voltage - V 0.790 0.785 0.780 0.775 0.770 0.765 0.760 0.755 0.750 -50 0 50 100 150 TJ - Junction Temperature - °C Figure 11. 14 Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 TPS53128 www.ti.com SLVSAE4 – JULY 2010 TYPICAL APPLICATION PERFORMANCE SWITCHING FREQUENCY (IO1 = 3 A) vs INPUT VOLTAGE (CH1) SWITCHING FREQUENCY (IO2 = 3 A) vs INPUT VOLTAGE (CH2) 500 fSW - Switching Frequency - kHz fSW - Switching Frequency - kHz 500 400 300 200 100 400 300 200 100 VO2 = 1.05 V VO1=1.8V 0 0 0 0 5 10 15 20 5 10 15 20 25 VIN - Input Voltage - V 25 VIN - Input Voltage - V Figure 12. Figure 13. SWITCHING FREQUENCY vs OUTPUT CURRENT (CH2) 400 400 350 350 fSW - Switching Frequency - kHz fSW - Switching Frequency - kHz SWITCHING FREQUENCY vs OUTPUT CURRENT (CH1) 300 250 200 150 100 VO1=1.8V 50 250 200 150 100 VO2=1.05V 50 0 0.01 300 0 0.1 1 10 0.01 IO - Output Current - A 0.1 1 10 IO - Output Current - A Figure 14. Figure 15. Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 15 TPS53128 SLVSAE4 – JULY 2010 www.ti.com OUTPUT VOLTAGE (VIN = 12 V) vs OUTPUT CURRENT (CH1) OUTPUT VOLTAGE (VIN = 12 V) vs OUTPUT CURRENT (CH2) 1.880 1.100 1.870 1.090 VO1=1.8V VO2=1.05V 1.080 1.850 VOUT - Output Voltage - V VOUT - Output Voltage - V 1.860 1.840 1.830 1.820 1.810 1.800 1.790 1.070 1.060 1.050 1.040 1.030 1.020 1.780 1.010 1.770 1.000 1.760 0.001 0.01 0.1 1 0.001 10 0.01 IOUT - Output Current - A 10 Figure 17. OUTPUT VOLTAGE (VIN = 12 V) vs INPUT VOLTAGE (CH1) OUTPUT VOLTAGE (VIN = 12 V) vs INPUT VOLTAGE (CH2) 1.100 1.880 1.870 1.860 1.850 1.840 1.830 1.820 1.810 1.800 1.790 1.780 1.770 1.760 1.090 VOUT2 - Output Voltage - V VOUT1 - Output Voltage - V 1 IOUT - Output Current - A Figure 16. 1.080 1.070 1.060 1.050 1.040 1.030 1.020 VO2=1.05V VO1=1.8V 1.010 1.000 0 5 10 15 VI - Input Voltage - V 20 25 0 Figure 18. 16 0.1 5 10 15 VI - Input Voltage - V 20 25 Figure 19. Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 TPS53128 www.ti.com SLVSAE4 – JULY 2010 LOAD TRANSIENT RESPONSE LOAD TRANSIENT RESPONSE VO2=1.05V (50mV/div) VO1=1.8V (50mV/div) IOUT2 (2A/div) IOUT1 (2A/div) Figure 20. Figure 21. START-UP WAVEFORMS START-UP WAVEFORMS EN2 (5 V/div) EN1 (5 V/div) SS2 (0.2 V/div) SS1 (0.2 V/div) VO1 = 1.8 V (0.5 V/div) VO2 = 1.05 V (0.5 V/div) Figure 22. Figure 23. Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 17 TPS53128 SLVSAE4 – JULY 2010 www.ti.com 1.05-V EFFICIENCY vs OUTPUT CURRENT (CH2) 100 100 90 90 80 80 70 70 Efficiency - % Efficiency - % 1.8-V EFFICIENCY vs OUTPUT CURRENT (CH1) 60 50 40 30 60 50 40 30 20 20 VO1=1.8V VO2=1.05V 10 10 0 0 0.001 0.01 0.1 1 10 0.001 0.01 0.1 IOUT - Output Current - A IOUT - Output Current - A Figure 24. Figure 25. 1.8-V OUTPUT RIPPLE VOLTAGE VO1=1.8V 10 1.05-V OUTPUT RIPPLE VOLTAGE VO2 (20mV/div) VO1 (20mV/div) VO2=1.05V Figure 26. 18 1 Figure 27. Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 TPS53128 www.ti.com SLVSAE4 – JULY 2010 APPLICATION INFORMATION 1. Choose inductor. The inductance value is selected to provide approximately 30% peak to peak ripple current at maximum load. Larger ripple current increases output ripple voltage, improve S/N ratio and contribute to stable operation. Equation 4 can be used to calculate L1. L1 = (V IN (max) - Vo1 )´ I L1( ripple) ´ fsw Vo1 V 3´ = (V IN (max) - Vo1 Io1´ fsw IN (max) )´ Vo1 V (4) IN (max) The inductors current ratings needs to support both the RMS (thermal) current and the Peak (saturation) current. The RMS and peak inductor current can be estimated as follows. VIN(MAX) - VO1 IL1(RIPPLE) = ¾ L1 · fSW · Vo1 ¾ VIN(MAX) (5) VTRIP ¾ IL1(PEAK) = R + IL1(RIPPLE) DS(ON) ¾ 2 1 (I IL1(RMS) = IO 12 + ¾ ) 12 L1(RIPPLE) (6) Ö (7) Note: The calculation above shall serve as a general reference. To further improve transient response, the output inductance could be reduced further. This needs to be considered along with the selection of the output capacitor. 2. Choose output capacitor. The capacitor value and ESR determines the amount of output voltage ripple and load transient response. it is recommended to use a ceramic output capacitor. IL1(RIPPLE) C1 = ¾ 8 · VO1(RIPPLE) · 1 ¾ fSW (8) 2 D Iload · L1 C1 = ¾ 2 · VO1 · DVOS (9) 2 load · L1 DI C1 = ¾ 2 · K · DVUS (10) Where Ton1 K = (VIN - VO 1) · ¾ Ton1 + Tmin(off) (11) Select the capacitance value greater than the largest value calculated from Equation 8, Equation 9 and Equation 10. The capacitance for C1 should be greater than 66 mF. Where ΔVOS = The allowable amount of overshoot voltage in load transition ΔVUS = The allowable amount of undershoot voltage in load transition Tmin(off) = Minimum off time 3. Choose input capacitor. The TPS53128 requires an input decoupling capacitor and a bulk capacitor is needed depending on the application. A minimum 10-mF high-quality ceramic capacitor is recommended for the input capacitor. The capacitor voltage rating needs to be greater than the maximum input voltage. Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 19 TPS53128 SLVSAE4 – JULY 2010 www.ti.com 4. Choose bootstrap capacitor. The TPS53128 requires a bootstrap capacitor from SW to VBST to provide the floating supply for the high-side drivers. A minimum 0.1-mF high-quality ceramic capacitor is recommended. The voltage rating should be greater than 10 V. 5. Choose VREG5 and V5FILT capacitor. The TPS53128 requires both the VREG5 regulator and V5FILT input are bypassed. A minimum 4.7-mF high-quality ceramic capacitor must be connected between the VREG5 and GND for proper operation. A minimum 1-mF high-quality ceramic capacitor must be connected between the V5FILT and GND for proper operation. Both of these capacitors’ voltage ratings should be greater than 10 V. 6. Choose output voltage divider resistors. The output voltage is set with a resistor divider from the output voltage node to the VFBx pin. It is recommended to use 1% tolerance or better resisters. Select R2 between 10 kΩ and 100 kΩ and use Equation 12 or Equation 13 to calculate R1. Vswinj = (VIN - VO1 · 0.5875) · R1 = ( )( ) 1 ¾ fSW ( VO1 ¾ VIN · ) VO 1 -1 ¾ VFB(RIPPLE) + Vswinj VFB + ¾ 2 · · 4975 (12) R2 (13) Where VFB(RIPPLE) = Ripple voltage at VFB Vswinj = Ripple voltage at error comparator 7. Choose register setting for over current limit. VTRIP = ( ) (VIN - VO) VO ·¾ IOCL - ¾ 2 · L1 · fSW VIN · RDS(ON) (14) VTRIP (mV) - VOCLoff RTRIP (kW) = ¾ ITRIP(min) (mA) (15) Where RDS(ON) = Low side FET on-resistance ITRIP(min) = TRIP pin source current （8.5 mA） VOCL0ff = Minimum over current limit offset voltage (–20 mV) IOCL = Over current limit 8. Choose soft start capacitor. Soft start time equation is as follows. TSS · ISSC CSS = ¾ VFB 20 (16) Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 TPS53128 www.ti.com SLVSAE4 – JULY 2010 LAYOUT SUGGESTIONS • • • • • • Keep the input switching current loop as small as possible. Place the input capacitor (C3,C6) close to the top switching FET. The output current loop should also be kept as small as possible. Keep the SW node as physically small and short as possible as to minimize parasitic capacitance and inductance and to minimize radiated emissions. Kelvin connections should be brought from the output to the feedback pin (FBx) of the device. Keep analog and non-switching components away from switching components. Make a single point connection from the signal ground to power ground. Do not allow switching current to flow under the device. Submit Documentation Feedback Copyright © 2010, Texas Instruments Incorporated Product Folder Link(s): TPS53128 21 PACKAGE OPTION ADDENDUM www.ti.com 13-Sep-2010 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Qty Eco Plan (2) Lead/ Ball Finish MSL Peak Temp (3) Samples (Requires Login) TPS53128PW ACTIVE TSSOP PW 24 60 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM Purchase Samples TPS53128PWR ACTIVE TSSOP PW 24 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM Request Free Samples TPS53128RGER ACTIVE VQFN RGE 24 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR Request Free Samples TPS53128RGET ACTIVE VQFN RGE 24 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR Purchase Samples (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. 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Addendum-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 10-Sep-2010 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 TPS53128PWR TSSOP PW 24 2000 330.0 16.4 6.95 8.3 1.6 8.0 16.0 Q1 TPS53128RGER VQFN RGE 24 3000 330.0 12.4 4.25 4.25 1.15 8.0 12.0 Q2 TPS53128RGET VQFN RGE 24 250 180.0 12.4 4.25 4.25 1.15 8.0 12.0 Q2 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 10-Sep-2010 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) TPS53128PWR TSSOP PW 24 2000 346.0 346.0 33.0 TPS53128RGER VQFN RGE 24 3000 346.0 346.0 29.0 TPS53128RGET VQFN RGE 24 250 190.5 212.7 31.8 Pack Materials-Page 2 MECHANICAL DATA MTSS001C – JANUARY 1995 – REVISED FEBRUARY 1999 PW (R-PDSO-G**) PLASTIC SMALL-OUTLINE PACKAGE 14 PINS SHOWN 0,30 0,19 0,65 14 0,10 M 8 0,15 NOM 4,50 4,30 6,60 6,20 Gage Plane 0,25 1 7 0°– 8° A 0,75 0,50 Seating Plane 0,15 0,05 1,20 MAX PINS ** 0,10 8 14 16 20 24 28 A MAX 3,10 5,10 5,10 6,60 7,90 9,80 A MIN 2,90 4,90 4,90 6,40 7,70 9,60 DIM 4040064/F 01/97 NOTES: A. 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