TMI3253SH

TMI3253SH 1MHz 18V 3.0A Synchronous COT Step-Down Converter Features Description ⚫ 70mΩ/35mΩ Low RDS(ON) internal FETs The TMI3253SH is a high efficiency 1MHz, ⚫ High Efficiency Synchronous-Mode Constant-on-Time Operation synchronous step-down DC-DC converter capable (COT) control mode of delivering up to 3.0A current with 1.2V output ⚫ Wide Input Range: 4.5V to 18V ⚫ Output Voltage from 0.6V ⚫ 1MHz Switch Frequency ⚫ Up to 3.0A Output Current@1.2VOUT ripple and small external inductor and capacitor ⚫ COT control to achieve fast transient size are achieved with 1MHz switching frequency. responses It adopts the COT architecture to achieve fast ⚫ Power Save Mode at Light Load transient responses for high voltage step down ⚫ Integrated internal compensation applications. ⚫ Stable with Low ESR Ceramic Output The TMI3253SH requires a minimum number of Capacitors readily available standard external components voltage. TMI3253SH integrates main switch and synchronous switch with very low RDS(ON) to minimize the conduction loss. Low output voltage and is available in a 6-pin SOT23-6 ROHS ⚫ Over Current Protection with Hiccup Mode ⚫ Thermal Shutdown ⚫ Inrush Current Limit and Soft Start Application ⚫ Build in Input Over Voltage Protection ⚫ ⚫ Digital Set Top Boxes Available in SOT23-6 Package ⚫ Flat Panel Television and Monitors compliant package. ⚫ Notebook computer ⚫ Wireless and DSL Modems Typical Application Efficiency VOUT=3.3V, TA=25°C C4 100% 0.1µF 95% L BS CIN1 CIN2 22µF 100nF 2.2µH 90% VOUT= 3.3V LX R3 100kΩ R1 39kΩ EN FB GND R2 8.66kΩ Efficiency VIN Cfb 20pF~ 100pF CO1 CO2 22µF 22µF 85% 80% 75% 70% 9V-3.3V 12V-3.3V 16V-3.3V 65% 60% 0.01 TMI and SUNTO are the brands of TOLL microelectronic TMI3253SH Rev. 1.1 – 2019.11 0.1 1 Output Current (A) 10 www.toll-semi.com 1 TMI3253SH Absolute Maximum Ratings (Note 1) Parameter Min Max Unit Input Supply Voltage, EN LX Voltages FB Voltage BS Voltage Storage Temperature Range Junction Temperature (Note2) Power Dissipation Lead Temperature (Soldering, 10s) -0.3 -0.3 -0.3 -0.3 -65 20 20 6 23 150 V V V V °C °C mW °C 160 1000 260 Package BS 1 6 LX GND 2 5 IN FB 3 4 EN SOT23-6 Top Marking: TS5XXX TS5: Device Code XXX: Inside Code Order Information Part Number Package Top Marking Quantity/Reel TMI3253SH SOT23-6 TS5XXX 3000 TMI3253SH devices are Pb-free and RoHS compliant. www.toll-semi.com 2 TMI and SUNTO are the brands of TOLL microelectronic TMI3253SH Rev.1.1 – 2020.02 TMI3253SH Pin Functions Pin Name Function 1 BS 2 GND 3 FB 4 EN 5 IN Power supply Pin 6 LX Switching Pin Bootstrap. A capacitor connected between LX and BS pins is required to form a floating supply across the high-side switch driver. Ground Pin Output Voltage feedback input. Connect FB to the center point of the external resistor divider. Drive this pin to a logic-high to enable the IC. Drive to a logic-low to disable the IC and enter micro-power shutdown mode. Don’t floating EN. ESD Rating Items Description Value Unit VESD_HBM Human Body Model for all pins ±2000 V VESD_CDM Charged Device Model for all pins ±2000 V JEDEC specification JS-001 Recommended Operating Conditions Items Description Min Max Unit Voltage Range IN 4.5 18 V TJ Operating Junction Temperature -40 125 °C Thermal Resistance (Note3) Items Description Value Unit θJA Junction-to-ambient thermal resistance 100 °C/W θJC Junction-to-case(top) thermal resistance 56 °C/W ψJC Junction-to-case(top) thermal characteristic parameter 3.5 °C/W TMI and SUNTO are the brands of TOLL microelectronic TMI3253SH Rev. 1.1 – 2019.11 www.toll-semi.com 3 TMI3253SH Electrical Characteristics VIN=12V, VOUT=3.3V, TA = 25°C, unless otherwise noted. Parameter Conditions Min Typ Max Unit 18 V Input Voltage Range 4.5 OVP Threshold 18.7 19.3 19.8 V UVLO Rising Threshold 4.0 4.2 4.35 V UVLO Hysteresis 0.4 0.45 0.5 V 300 450 μA 5 10 μA 0.6 0.612 V Quiescent Current VEN=2V, VFB=VREF x 105% Shutdown Current VIN=12V, EN=0V Regulated Feedback Voltage TA=25°C, 4.5V≤VIN≤18V 0.588 High-Side Switch On-Resistance 70 mΩ Low-Side Switch On-Resistance 35 mΩ High-Side Switch Leakage Current VEN=0V, VLX=0V Switch Valley Current Limit Minimum Duty Cycle 3.7 On Time VIN=12V, VOUT=1.2V, IOUT=1A Oscillation Frequency 1 10 μA 4 4.5 A 90 120 160 ns 900 1000 1100 kHz Maximum Duty Cycle 65 % Minimum On-Time (Note 4) 60 80 100 ns Soft Start Time 0.6 0.8 1.2 ms Hiccup on Time (Note 4) 1.2 ms Hiccup Time Before Restart (Note 4) 3.6 ms EN Rising Threshold 0.85 0.95 1.05 V EN Falling Threshold 0.75 0.85 0.95 V EN Hysteresis 100 mV Thermal Shutdown Threshold (Note 4) 165 °C Thermal Shutdown Hysteresis (Note 4) 30 °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. The maximum allowable continuous power dissipation at any ambient temperature is calculated by PD (MAX) = (TJ(MAX)-TA)/θJA. Note 3: Measured on JESD51-7, 4-layer PCB. ψJC is measure on top case of device on JESD51-7, 4layer PCB with natural heat dissipation. Note 4: Guaranteed by design. www.toll-semi.com 4 TMI and SUNTO are the brands of TOLL microelectronic TMI3253SH Rev.1.1 – 2020.02 TMI3253SH Block Diagram EN VIN BS Regulator UVLO OVP Vuv + OTP Hiccup Logic Control PWM Comparator FB + EA + Voltage Reference VCOMP LX Gate Driver + - ON time Generater + ZC - Soft Start Current Sense and OCP GND Figure 1. TMI3253SH Block Diagram Operation Description Internal Regulator The TMI3253SH is a constant on-time (COT) step down DC/DC converter that provides excellent transient response with no extra external compensation components. This device contains low resistance, high voltage high side and low side power MOSFETs, and operates at 1MHz operating frequency to ensure a compact, high efficiency design with excellent AC and DC performance. Error Amplifier TMI3253SH adopts operational transconductance amplifier (OTA) as error amplifier. The error amplifier compares the FB pin voltage with the internal FB reference (VREF) and outputs a current proportional to the difference between the two. This output current is then used to charge or discharge the internal compensation network to form the VCOMP voltage, which is used to compare with the low side power MOSFET current sensing signal and trigger on time pulse. The optimized internal compensation network minimizes the external component counts and simplifies the control loop design. TMI and SUNTO are the brands of TOLL microelectronic TMI3253SH Rev. 1.1 – 2019.11 www.toll-semi.com 5 TMI3253SH Internal Soft-Start The soft-start is implemented to prevent the converter output voltage from overshooting during startup. When the chip starts, the internal circuitry generates a soft-start voltage (SS) ramping up from 0V to 0.6V. When it is lower than the internal FB reference (VREF), SS overrides REF so the error amplifier uses SS as the reference. When SS is higher than VREF, VREF regains control. The SS time is internally fixed to 0.8ms typically. Over-Current-Protection and Short Circuits Protection The TMI3253SH has cycle-by-cycle valley current limit function. When the inductor current valley value is larger than the valley current limit during low side MOSFET on state, the device enters into valley over current protection mode and low side MOSFET keeps on state until inductor current drops down to the value equal or lower than the valley current limit, and then on time pulse could be generated and high side MOSFET could turn on again. 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 65% of VREF, TMI3253SH 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 TMI3253SH hiccup mode is typically 4.8ms. Startup and Shutdown If both VIN and EN are higher than their appropriate thresholds, the chip starts switching operation. The reference block starts first, generating stable reference voltage and currents, and then the internal regulator is enabled. The regulator provides stable supply for the remaining circuitries. Three events can shut down the chip: EN low, VIN low and thermal shutdown. In the shutdown procedure, the signaling path is first blocked to avoid any fault triggering. The VCOMP voltage and the internal supply rail are then pulled down. The floating driver is not subject to this shutdown command. Application Information Setting the Output Voltage The external resistor divider is used to set the output voltage (see Typical Application on page 1). Choose R1 to be around 39kΩ for optimal transient response. R2 is then given by: Table 1: Selection for Common Output Voltages (VFB=0.6V) VOUT (V) R1 (kΩ) R2 (kΩ) CFB(pF) L (μH) 5 39 5.36 33 2.2 3.3 39 8.66 33 2.2 2.5 39 12.4 33 2.2 1.8 39 19.6 33 1.5 1.5 39 26.1 33 1.5 1.2 39 39 33 1.5 1 39 59 33 1.0 R2 = R1 Vout /VFB − 1 C fb=20pF~100pF TMI3253SH VOUT FB R1 R2 Figure 2. Feedback Network www.toll-semi.com 6 TMI and SUNTO are the brands of TOLL microelectronic TMI3253SH Rev.1.1 – 2020.02 TMI3253SH Selecting the Inductor A 1.0μH to 2.2μH inductor with a DC current rating of at least 25% percent higher than the maximum load current is recommended for most applications. For highest efficiency, the inductor DC resistance should be as small as possible. For most designs, the inductance value can be derived from the following equation. V  (Vin − Vout ) L = out Vin  I L  fOSC Where ΔIL is the inductor ripple current. Choose inductor ripple current to be approximately 30% if the maximum load current, 3A. The maximum inductor peak current is: I L ( MAX ) = I LOAD + I L 2 Under light load conditions below 100mA, larger inductance is recommended for improved efficiency. Selecting the Output Capacitor The output capacitor (Co1 and Co2) is required to maintain the DC output voltage. Ceramic, tantalum, or low ESR electrolytic capacitors are recommended. Low ESR capacitors are preferred to keep the output voltage ripple low. The output voltage ripple can be estimated by: VOUT =  VOUT  VOUT   1  1 −    RESR +  f S  L  VIN   8  f S  C2  Where L is the inductor value and RESR is the equivalent series resistance (ESR) value of the output capacitor. In the case of ceramic capacitors, the impedance at the switching frequency is dominated by the capacitance. The output voltage ripple is mainly caused by the capacitance. For simplification, the output voltage ripple can be estimated by:  V   1 − OUT  8  f S  L  C2  VIN  In the case of tantalum or electrolytic capacitors, the ESR dominates the impedance at the switching VOUT = VOUT 2 frequency. For simplification, the output ripple can be approximated to: VOUT = VOUT  VOUT   1 −   RESR f S  L  VIN  The characteristics of the output capacitor also affect the stability of the regulation system. The TMI3253SH can be optimized for a wide range of capacitance and ESR values. TMI and SUNTO are the brands of TOLL microelectronic TMI3253SH Rev. 1.1 – 2019.11 www.toll-semi.com 7 TMI3253SH Typical Performance Characteristics Efficiency Efficiency VOUT =3.3V, L=2.2μH, DCR=20mΩ VOUT =5V, L=2.2μH, DCR=30mΩ 95% 90% 90% Efficiency 100% 95% Efficiency 100% 85% 80% 75% 70% 60% 0.01 0.1 1 Output Current (A) 80% 75% 70% 9V-3.3V 12V-3.3V 16V-3.3V 65% 85% 10 60% 0.01 Efficiency 90% 1.5% Efficiency 80% 70% 60% 50% 9V-1.2V 12V-1.2V 16V-1.2V Output Voltage Regulation 2.0% 20% 0.01 10 VIN=12V, TA=25°C 100% 30% 0.1 1 Output Current (A) Load Regulation VOUT=1.2V, L=1.5μH, DCR=20mΩ 40% 9V-5V 12V-5V 16V-5V 65% Vo=5V Vo=3.3V 1.0% Vo=1.2V 0.5% 0.0% -0.5% -1.0% -1.5% -2.0% 0.1 1 Output Current (A) 10 0 Load Transient 0.5 1 1.5 2 2.5 Output Current (A) 3 3.5 Load Transient VIN =12V, VOUT =3.3V, Io =0A to 3A VIN =12V, VOUT =3.3V, Io =1.5A to 3A Vout=200mV/div AC coupled Vout=200mV/div AC coupled Io=2A/div Io=2A/div Time: 200μs/div www.toll-semi.com 8 Time: 200μs/div TMI and SUNTO are the brands of TOLL microelectronic TMI3253SH Rev.1.1 – 2020.02 TMI3253SH Typical Performance Characteristics(continued) Output Short Entry Output Short Recovery VIN =12V, VOUT =3.3V, No Load VIN=12V, VOUT =3.3V, No Load Vout=2V/div Vout=2V/div Vin=5V/div Vin=5V/div LX=10V/div LX=10V/div IL=5A/div Time: 4ms/div IL=5A/div Input Power On Time: 4ms/div Input Power Down VIN =12V, VOUT =3.3V, Io =Full Load VIN =12V, VOUT =3.3V, Io =Full Load Vout=2V/div Vin=5V/div Vout=2V/div LX=10V/div Vin=5V/div LX=10V/div IL=2A/div IL=2A/div Time: 400μs/div Time: 10ms/div EN Enable EN Disable VIN =12V, VOUT =3.3V, Io =Full Load VIN =12V, VOUT =3.3V, Io =Full Load Vout=2V/div Vout=2V/div LX=10V/div LX=10V/div EN=5V/div EN=5V/div IL=2A/div TMI and SUNTO are the brands of TOLL microelectronic TMI3253SH Rev. 1.1 – 2019.11 IL=2A/div Time: 400μs/div Time: 40μs/div www.toll-semi.com 9 TMI3253SH Typical Application Circuits C4 0.1µF L BS VIN CIN1 CIN2 22µF 100nF 2.2µH VOUT=5V LX R3 100kΩ R1 39kΩ EN Cfb 20pF~ 100pF FB CO1 R2 5.36kΩ GND CO2 22µF 22µF Figure 4. 12VIN, 5V Output (VFB=0.6V) C4 0.1µF L BS VIN CIN1 CIN2 22µF 100nF 2.2µH VOUT= 3.3V LX R3 100kΩ R1 39kΩ Cfb 20pF~ 100pF EN FB CO1 R2 8.66kΩ GND 22µF CO2 22µF Figure 5. 12VIN, 3.3V Output (VFB=0.6V) C4 0.1µF L 1.5µH BS VIN CIN1 CIN2 22µF 100nF VOUT= 1.8V LX R3 100kΩ R1 39kΩ Cfb 20pF~ 100pF EN FB GND CO1 R2 19.6kΩ 22µF CO2 22µF Figure 6. 12VIN, 1.8V Output (VFB=0.6V) www.toll-semi.com 10 TMI and SUNTO are the brands of TOLL microelectronic TMI3253SH Rev.1.1 – 2020.02 TMI3253SH Typical Application Circuits(continued) C4 0.1µF L 1.5µH BS VIN CIN1 CIN2 22µF 100nF VOUT= 1.5V LX R3 100kΩ R1 39kΩ Cfb 20pF~ 100pF EN FB CO1 R2 26.1kΩ GND 22µF CO2 22µF Figure 7. 12VIN, 1.5V Output (VFB=0.6V) C4 0.1µF L 1.5µH BS VIN CIN1 CIN2 22µF 100nF VOUT= 1.2V LX R3 100kΩ R1 39kΩ Cfb 20pF~ 100pF EN FB CO1 R2 39kΩ GND 22µF CO2 22µF Figure 8. 12VIN, 1.2V Output (VFB=0.6V) C4 0.1µF L BS VIN CIN1 CIN2 22µF 100nF 1µH VOUT= 1V LX R3 100kΩ R1 39kΩ Cfb 20pF~ 100pF EN FB GND CO1 R2 59kΩ 22µF CO2 22µF Figure 9. 12VIN, 1V Output (VFB=0.6V) TMI and SUNTO are the brands of TOLL microelectronic TMI3253SH Rev. 1.1 – 2019.11 www.toll-semi.com 11 TMI3253SH PCB Layout Guide PCB layout is very important to achieve stable operation. It is highly recommended to duplicate EVB layout for optimum performance. If change is necessary, please follow these guidelines and take Figure 3 for reference. 1) Keep the path of switching current short and minimize the loop area formed by Input capacitor, IN pin and GND. 2) Bypass ceramic capacitors are suggested to be put close to the IN Pin. 3) Ensure all feedback connections are short and direct. Place the feedback resistors as close to the chip as possible. 4) VOUT, LX away from sensitive analog areas such as FB. 5) Connect IN, LX, and especially GND respectively to a large copper area to cool the chip to improve thermal performance and long-term reliability. www.toll-semi.com 12 TMI and SUNTO are the brands of TOLL microelectronic TMI3253SH Rev.1.1 – 2020.02 TMI3253SH Package Information SOT23-6 Unit: mm Dimensions In Millimeters Symbol Dimensions In Millimeters Symbol Min Typ Max Min Typ Max A 2.80 2.90 3.00 L3 1.800 1.900 2.000 B 2.60 2.80 3.00 L4 0.077 0.127 0.177 B1 1.50 1.60 1.70 L5 - 0.250 - C - - 1.05 L6 - 0.600 - C1 0.60 0.80 1.00 θ 0° C2 0.35 0.40 0.45 Θ1 10° 12° 14° C4 0.223 0.273 0.323 Θ2 10° 12° 14° K 0.000 0.075 0.150 R - 0.100 - L 0.325 0.400 0.475 R1 - 0.100 - L1 0.325 0.450 0.550 R2 - 0.100 - L2 0.850 0.950 1.050 TMI and SUNTO are the brands of TOLL microelectronic TMI3253SH Rev. 1.1 – 2019.11 0° www.toll-semi.com 13 TMI3253SH Tape and Reel Information Tape Dimensions: Reel Dimensions: 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 TMI3253SH Rev.1.1 – 2020.02