TMI33431E

TMI33431E 30V, 3A Synchronous Step-Down DC/DC Converter with Adjustable Soft-start Time FEATURES GENERAL DESCRIPTION TMI33431E is a wide input voltage of 4.5V to 30V, high efficiency current mode, synchronous stepdown DC/DC converter capable of delivering 3A current with adjustable soft-start time. TMI33431E integrates main switch and synchronous switch with low RDS(on) to minimize the conduction loss. The device integrates 120mΩ High-Side and 80mΩ Low-side Power MOS, and has advanced features include UVLO, Thermal Shutdown, Soft Start, input OVP. High Efficiency: Up to 95%@12V to 5V ⚫ Wide input voltage: 4.5V ~ 30V ⚫ Up to 3A Output Current ⚫ Low Typical 3μA Shutdown Current ⚫ Adjustable Soft-Start Time ⚫ Fixed 570kHz Switching Frequency ⚫ Stable with Low ESR Ceramic Output ⚫ Peak Current Mode with External Compensation ⚫ PFM in Light Load Condition ⚫ 0.8V Voltage Reference with ±2% Accuracy ⚫ Thermal Shutdown ⚫ APPLICATIONS Cycle-by-cycle Current Limit Protection ⚫ Over Current Protection with Hiccup Mode ⚫ ESOP8 Package ⚫ Vacuum Robot ⚫ Smart Home Applications ⚫ Printer ⚫ Consumer Applications: TV and Set Top Box ⚫ General 5V, 12V, 24V DC/DC Power Bus Supply ⚫ TYPICAL APPILCATION Efficiency R5 0Ω Vin=8V~30V C2 10 μF C3 0.1μF IN 0.1μF BS L 10μH Vout=5V SW on EN off C6 TMI33431E SS R1 52.3kΩ 10pF Optional C7 C8 90% 22μF 22μF 80% FB 10nF Css 100% GND COMP C5 6.8nF R4 3.3kΩ R2 10kΩ C4 10pF Optional Figure 1. Basic Application Circuit TMI and SUNTO are the brands of TOLL microelectronic TMI33431E V1.0 2019.11 Efficiency C1 VOUT=5V, IOUT=0.001A to 3.0A, TA=25°C 70% 60% 50% 40% 9V-5V 30% 12V-5V 20% 0.001 24V-5V 0.01 0.1 Output Current (A) 1 10 www.toll-semi.com 1 TMI33431E ABSOLUTE MAXIMUM RATINGS (Note 1) Parameter Value Unit Input Supply Voltage, SW -0.3~33 V BS to SW Voltage -0.3~6.0 V All Other Pins (FB, EN, SS, COMP) Voltage -0.3~6.0 V Storage Temperature Range -50~150 °C Junction Temperature (Note2) -40~150 °C Package Dissipation 2 W PACKAGE/ORDER INFORMATION BS 1 8 IN 7 GND 2 EN 3 Exposed Pad Power GND SS 4 SW 6 COMP 5 FB ESOP8 Top Mark: T33431E/YYXXX (T33431E: Device Code, YYXXX: Inside Code) Part Number Package TMI33431E ESOP8 Top mark T33431E YYXXX Quantity/ Reel 3000 TMI33431E devices are Pb-free and RoHS compliant. www.toll-semi.com 2 TMI and SUNTO are the brands of TOLL microelectronic TMI33431E V1.0 2019.11 TMI33431E PIN FUNCTIONS Pin Name 1 BS 2 IN 3 EN Function High-side Gate Driver Bootstrap pin, Provide supply to high-side LDMOS Gate Driver. Connect a 100nF capacitor between BS and SW Power Input pin Enable Pin. Drive EN above 1.5V to turn on the device. Drive EN below 0.4V to turn it off. Do not leave EN floating. The SS pin is the soft-start and tracking pin. An external capacitor connected to this pin 4 SS sets the internal voltage-reference rise time. The voltage on this pin overrides the internal reference. 5 FB Feedback Pin 6 COMP 7 GND Ground Pin 8 SW Switch Pin, Connect to external Inductor External Compensation Pin ESD RATING Items Description Value Unit VESD_HBM Human Body Model for all pins ±2000 V JEDEC specification JS-001 RECOMMENDED OPERATING CONDITIONS Items Description Min Max Unit Voltage Range VIN 4.5 30 V THERMAL RESISITANCE (Note 3) Items Description Value Unit θJA Junction-to-ambient thermal resistance 60 °C/W TMI and SUNTO are the brands of TOLL microelectronic TMI33431E V1.0 2019.11 www.toll-semi.com 3 TMI33431E ELECTRICAL CHARACTERISTICS (Note 3) (VIN=12V, VOUT=5V, TA = 25°C, unless otherwise noted.) Parameter Symbol Conditions Input Voltage Range Under Voltage Lockout UVLO Hysteresis Input OVP Voltage VIN VUVLO Min Typ 4.5 VIN rising Max Unit 30 V 4.3 V VUVLO_HY 0.35 V VINOVP 32 V Input Quiescent Current IQ VFB=1V 0.45 Input Supply Current IIN No load 0.5 Shutdown Current ISD EN = 0V 3 10 μA 800 816 mV 50 nA Feedback Threshold Voltage FB Pin input current VFBTH PWM operation 784 0.52 mA mA IFB -50 EN High Level Input Voltage VEN_High 1.5 EN Low Level Input Voltage VEN_Low 0.4 V EN sink current IEN_Sink 1 mA Soft start Time TSS V CSS=NC 1.2 ms CSS=10nF 3.5 ms 4.2 A Current limit cycle-by-cycle ILIM_MAX SW leakage ISW_LEAK Switch On-Resistance (high side) RDSONH 120 mΩ Switch On-Resistance (low side) RDSONL 80 mΩ FSW 570 kHz TON_MIN 200 ns Hiccup on Time (Note 3) 2 ms Hiccup Time Before Restart 64 ms Switching Frequency Minimum Turn-on Time (Note 3) 10 μA Maximum Duty-cycle DMAX 92 % Thermal Shutdown Threshold (Note 3) TSDN 160 °C Thermal Shutdown Hysteresis (Note 3) TSDN_HY 10 °C Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: TJ is calculated from the ambient temperature TA and power dissipation PD according to the following formula: TJ = TA + (PD) x θJA. Note 3: Guaranteed by design. www.toll-semi.com 4 TMI and SUNTO are the brands of TOLL microelectronic TMI33431E V1.0 2019.11 TMI33431E FUNCTIONAL BLOCK DIAGRAM VIN EN UVLO OVP 5V Enable Threahold Current Sense Themal Hiccup VUV Hiccup Shutdown + Shutdown Logic - Bootstrap circuits BS HS MOSFET Current-Limit ISS + + FB + + EA Logic Control SW PWM Comparator Slope Compensation 0.8V Voltage Reference LS MOSFET Current-Limit Oscillator Vin Current Sense Regulator GND SS COMP Figure 2. TMI33431E Block Diagram TMI and SUNTO are the brands of TOLL microelectronic TMI33431E V1.0 2019.11 www.toll-semi.com 5 TMI33431E FUNCTION DESCRIPTION Overview As seen in Functional Block Diagram, the TMI33431E is a peak current mode pulse width modulation (PWM) converter with fixed 570kHz switching frequency. The converter operates as follows: A switching cycle starts when the rising edge of the oscillator clock output causes the High-Side Power Switch to turn on and the Low-Side Power Switch to turn off. With the SW side of the inductor now connected to IN, the inductor current ramps up to store energy in the magnetic field. The inductor current level is measured by the Current Sense Amplifier and added to the Oscillator ramp signal. If the resulting summation is higher than the COMP voltage, the output of the PWM Comparator goes high. When this happens or when Oscillator clock output goes low, the High-Side Power Switch turns off. At this point, the SW side of the inductor swings to a diode voltage below ground, causing the inductor current to decrease and magnetic energy to be transferred to output. This state continues until the cycle starts again. The High-Side Power Switch is driven by logic using BS as the positive rail. This pin is charged to VSW + 5V when the Low-Side Power Switch turns on. The COMP voltage is the integration of the error between FB input and the internal 0.8V reference. If VFB is lower than the reference voltage, COMP tends to go higher to increase inductor current to the output side and try to increase output voltage. In light or no load condition, TMI33431E is operating in PFM mode for power saving. In PFM mode, the device ramps up its output voltage with one or several SW switching pulse, while the error amplifier output voltage VCOMP drops. The device stops switching when VCOMP voltage drops down the inner threshold, then the output voltage falls down and VCOMP voltage rises until VCOMP voltage is high enough to generate SW switching pulse. Input Over Voltage Protection The threshold of input OVP circuit include is typical 32V. Once the input voltage is higher than the threshold, the high-side MOSFET is turned off. When the input voltage drops lower than the threshold with hysteresis, the high-side MOSFET will be enabled again. This function protects device from switching in abnormal high input voltage and input surge condition. Over-Current-Protection and Short Circuits Protection The TMI33431E has cycle-by-cycle peak current limit function. The periodic current limit of the high side MOSFET can protect this device in case of overload, and prevent the current from losing control through valley current limit. Low side charge current limiting can shut down low side MOSFET to prevent excessive reverse current. If the output is short to GND and the output voltage drop until feedback voltage VFB is below the output under-voltage VUV threshold which is typically 35% of VREF, TMI33431E enters into hiccup mode to periodically disable and restart switching operation. The hiccup mode helps to reduce power dissipation and thermal rise during output short condition. The period of TMI33431E hiccup mode is typically 66ms. www.toll-semi.com 6 TMI and SUNTO are the brands of TOLL microelectronic TMI33431E V1.0 2019.11 TMI33431E Input Under Voltage Lockout TMI33431E implements input under voltage lockout function to avoid mis-operation at low input voltages. When the input voltage is lower than input UVLO threshold with UVLO hysteresis, the device is shut down. The typical 350mV input UVLO hysteresis value of TMI33431E is useful to prevent device from abnormal switching caused by input voltage oscillation around UVLO threshold during input voltage power-up and power-down with high load condition. Enable and Disable TMI33431E EN pin has a 5V Zener diode to clamp EN pin voltage. Drive EN to logic high level to turn on the device. Drive EN to logic low level to turn it off. If there is no EN logic control signal implemented on EN pin, EN could be pulled up to input voltage by a resistor. Please note the pull-up resistance value and make sure EN sink current is smaller than 1mA. EN pin cannot be floating. Thermal Shutdown The TMI33431E disables switching when its junction temperature exceeds 160°C typically, Once the device junction temperature falls below the threshold with hysteresis, TMI33431E returns to normal operation automatically. TMI and SUNTO are the brands of TOLL microelectronic TMI33431E V1.0 2019.11 www.toll-semi.com 7 TMI33431E APPLICATION INFORMATION Output Voltage Setting Vout R1 Cfb TMI33431E FB R2 Figure 3. Output Voltage Setting Figure 3 shows the connections for setting the output voltage. Select the proper ratio of the two feedback resistors R1 and R2 based on the output voltage. Adding a capacitor in parallel with R1 helps the system stability. Typically, use R2 ≈ 10kΩ and determine R1 from the following equation: R1=R2∙ ( VOUT -1) VREF Soft-Start Time Setting The TMI33431E device use the SS pin voltage as the reference voltage and regulates the output accordingly. A capacitor on the SS pin to ground implements a soft-start time. The device has an internal pullup current source of 2.6μA that charges the external soft-start capacitor. Use following equation to calculate the soft time (tSS, 10% to 90%) and soft capacitor (CSS). tSS (ms)= CSS (nF) × VREF (V) ISS where VREF is the voltage reference (0.8V) ISS is the soft-start charge current (2.6μA) Inductor Selection Inductance value is related to inductor ripple current value, input voltage, output voltage setting and switching frequency. The inductor value can be derived from the following equation: L= VOUT ×(VIN -VOUT ) VIN ×∆IL ×fSW Where ∆IL is inductor ripple current. Large value inductors result in lower ripple current and small value inductors result in high ripple current, so inductor value has effect on output voltage ripple value, however large value inductor have large size and is more expensive. DC resistance of inductor which has impact on efficiency of DC/DC converter should be taken into account when selecting the inductor. The saturation current rating of the inductor should be considered. The saturation current must be larger than peak inductor current with maximum load conditions in all operation conditions, for example, maximum load transient condition. The peak inductor current value can be calculated according to the www.toll-semi.com 8 TMI and SUNTO are the brands of TOLL microelectronic TMI33431E V1.0 2019.11 TMI33431E following equation. Meanwhile, if the system has output short condition, the saturation current of inductor should cover peak current limit value of the device. IL_peak = IOUT_MAX + VOUT × (VIN_MAX - VOUT ) 1 × ∆IL = IOUT_MAX + 2 2 × VIN_MAX × L × fSW Input Capacitor Selection Since the input current of the Buck converter is discontinuous, the input capacitor is needed to supply the AC current while maintaining the DC input voltage. The input capacitor impedance at the switching frequency should be less than input source impedance to prevent high frequency switching current passing to the input. A low ESR input capacitor sized for maximum RMS current must be used. Ceramic capacitors with X5R or X7R dielectrics are highly recommended because of their low ESR and small temperature coefficients. The voltage rating should be greater than the maximum input voltage plus input voltage ripple. A 10µF effective capacitance value ceramic capacitor for most applications is sufficient. A large value may be used for improved input voltage filtering. Additionally, a small 0.1μF ceramic capacitor located close on input pin and GND pad is help for high frequency filter. Output Capacitor Selection The output capacitor is required to keep the output voltage ripple small in steady status and load transient condition, and to ensure regulation loop stability. The output ripple △VOUT is determined by: ∆VOUT ≈∆IL × (RESR + 1 VOUT × (VIN - VOUT ) 1 )= × (RESR + ) 8 × fSW × COUT 2 × VIN × L × fSW 8 × fSW × COUT Where RESR is the equivalent series resistance value of output capacitor. As shown in above equation, the smaller ESR value and larger capacitance value of output capacitors, the smaller output voltage ripple. If ceramic capacitors are used as output capacitors, the output ripple is mainly depended on output capacitance value since the ceramic capacitors have low ESR value. If tantalum or electrolytic capacitors are used as output capacitors, RESR dominates the output ripple value since the electrolytic capacitors have significantly higher ESR value. The TMI33431E can be optimized for a wide range of output capacitance and ESR values. PC Board Layout Guidance When laying out the printed circuit board, the following checklist should be used to ensure proper operation of the IC. 1) Arrange the power components to reduce the AC loop size consisting of CIN, IN pin and SW pin. 2) Place input decoupling ceramic capacitor CIN as close to IN pin as possible. CIN is connected power GND with vias or short and wide path. 3) Return FB, COMP and SS/RT to signal GND pin, and connect the signal GND to power GND at a single point for best noise immunity. Connect exposed pad to power ground copper area with copper and vias. 4) Use copper plane for power GND for best heat dissipation and noise immunity. 5) Place feedback resistor close to FB pin. 6) Use short trace connecting BS-CBS-SW loop TMI and SUNTO are the brands of TOLL microelectronic TMI33431E V1.0 2019.11 www.toll-semi.com 9 TMI33431E TYPICAL PERFORMANCE CHARACTERISTICS (VIN=12V, VOUT=5V, CIN=22μF, COUT=22μFx2, L=10μH, TA=25°C, unless otherwise noted.) Efficiency Efficiency VOUT=5V, TA=25°C VOUT=3.3V, TA=25°C 90% 90% 80% 80% Efficiency 100% Efficiency 100% 70% 60% 50% 40% 9V-5V 30% 12V-5V 0.01 0.1 Output Current (A) 1 60% 50% 40% 9V-3.3V 30% 12V-3.3V 24V-3.3V 20% 0.001 24V-5V 20% 0.001 70% 0.01 10 Line Regulation 10 VOUT=5V, TA=25°C 5.1 2.00% 5 1.50% 4.9 1.00% Load Regulation(%) Output Voltage (V) 1 Load Regulation VOUT=5V, TA=25°C 4.8 4.7 4.6 Io=0A 4.5 0.50% 0.00% -0.50% Vin=9V Vin=12V Vin=24V -1.00% -1.50% Io=1A -2.00% 4.4 4 8 12 16 20 24 28 32 0 Input Voltage (V) Steady State 0.5 1 1.5 2 Output Current(A) 3 Vin=12V, VOUT=5V, IOUT=3A, TA=25°C VOUT=20mV/div AC coupled VOUT=10mV/div AC coupled SW=10V/div SW=10V/div VIN=50mV/div AC coupled VIN=500mV/div AC coupled IL=500mA/div IL=2A/div Time: 2μs/div www.toll-semi.com 2.5 Steady State Vin=12V, VOUT=5V, IOUT=0A, TA=25°C 10 0.1 Output Current (A) Time: 1μs/div TMI and SUNTO are the brands of TOLL microelectronic TMI33431E V1.0 2019.11 TMI33431E TYPICAL PERFORMANCE CHARACTERISTICS (Continued) Output Short Entry Output Short Recovery VIN=12V, VOUT=5V, No load VIN=12V, VOUT=5V, No Load VOUT=5V/div VOUT=5V/div VIN=5V/div VIN=5V/div SW=10V/div SW=10V/div IL=5A/div IL=5A/div Time: 40ms/div Time: 40ms/div VIN Power On VIN Power Off VIN=12V, VOUT=5V, Io=3A VIN=12V, VOUT=5V, Io=3A VOUT=5V/div VOUT=5V/div VIN=5V/div VIN=5V/div SW=10V/div SW=10V/div SW=10V/div IL=2A/div IL=2A/div Time: 400μs/div Time: 10ms/div Power On through EN Power Off through EN VIN=12V, VOUT=5V, RO=1.6Ω VIN=12V, VOUT=5V, RO=1.6Ω VEN=5V/div VEN=5V/div VOUT=5V/div VOUT=5V/div SW=10V/div SW=10V/div IL=2A/div IL=2A/div Time: 2ms/div TMI and SUNTO are the brands of TOLL microelectronic TMI33431E V1.0 2019.11 Time: 20μs/div www.toll-semi.com 11 TMI33431E TYPICAL PERFORMANCE CHARACTERISTICS (Continued) Load Transient Load Transient VIN=12V, VOUT=5V, IOUT = 0A to 3A VIN=12V, VOUT=5V, IOUT = 1.5A to 3A VOUT=200mV/div VOUT=500mV/div IO=2A/div IO=2A/div Time: 200μs/div www.toll-semi.com 12 Time: 200μs/div TMI and SUNTO are the brands of TOLL microelectronic TMI33431E V1.0 2019.11 TMI33431E PACKAGE INFORMATION ESOP8 Unit: mm Symbol Dimensions In Millimeters Min Max A 4.70 5.10 B 3.70 L 6.00 E Symbol Dimensions In Millimeters Min Max C 1.35 1.75 4.10 a 0.35 0.49 6.40 R 0.30 0.60 P 0° 7° 1.27 BSC K 0.02 0.10 b 0.40 1.25 A1 3.1 3.5 B1 2.2 2.6 Note: 1) All dimensions are in millimeters. 2) Package length does not include mold flash, protrusion or gate burr. 3) Package width does not include inter lead flash or protrusion. 4) Lead popularity (bottom of leads after forming) shall be 0.10 millimeters max. 5) Pin 1 is lower left pin when reading top mark from left to right. TMI and SUNTO are the brands of TOLL microelectronic TMI33431E V1.0 2019.11 www.toll-semi.com 13 TMI33431E TAPE AND REEL INFORMATION TAPE DIMENSIONS: REEL DIMENSIONS: Unit: mm A B C D E F T1 Ø 330±1 12.7±0.5 16.5±0.3 Ø 99.5±0.5 Ø 13.6±0.2 2.8±0.2 1.9±0.2 Note: 1) All Dimensions are in Millimeter 2) Quantity of Units per Reel is 3000 3) MSL level is level 3. www.toll-semi.com 14 TMI and SUNTO are the brands of TOLL microelectronic TMI33431E V1.0 2019.11