TMI3252SH

TMI3252SH 1MHz 18V 2A Synchronous COT Step-Down Converter Features Description ⚫ 140mΩ/70mΩ Low RDS(ON) internal FETs The TMI3252SH 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 2A current. TMI3252SH ⚫ Wide Input Range: 4.5V to 18V ⚫ Output Voltage from 0.6V ⚫ 1MHz Switch Frequency ⚫ Up to 2A Output Current inductor and capacitor size are achieved with ⚫ COT control to achieve fast transient 1MHz switching frequency. It adopts the COT responses architecture to achieve fast transient responses for ⚫ Power Save Mode at Light Load high voltage step down applications. ⚫ Integrated internal compensation The TMI3252SH requires a minimum number of ⚫ Stable with Low ESR Ceramic Output readily available standard external components Capacitors and is available in a 6-pin SOT23-6 ROHS integrates main switch and synchronous switch with very low RDS(ON) to minimize the conduction loss. Low output voltage ripple and small external ⚫ Over Current Protection with Hiccup Mode ⚫ Thermal Shutdown ⚫ Inrush Current Limit and Soft Start ⚫ Build in Input Over Voltage Protection ⚫ Available in SOT23-6 Package compliant package. Application ⚫ Digital Set Top Boxes ⚫ Flat Panel Television and Monitors ⚫ Notebook computer ⚫ Wireless and DSL Modems Typical Application Efficiency VOUT=3.3V, TA=25°C C4 100% 0.1µF 90% VIN CIN1 CIN2 22µF 100nF 2.2µH VOUT= 3.3V Efficiency L BS LX R3 100kΩ R1 39kΩ EN FB GND R2 8.66kΩ Cfb 20pF~ 100pF 80% 70% 60% CO1 50% 22µF 40% 30% 0.001 VIN=9V VIN=12V VIN=16V 0.01 0.1 1 10 Output Current (A) TMI and SUNTO are the brands of TOLL microelectronic TMI3252SH Rev. 1.0 – 2019.10 www.toll-semi.com www.suntosemi.com 1 TMI3252SH 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 150 1000 260 Package BS 1 6 LX GND 2 5 IN FB 3 4 EN SOT23-6 Top Marking: TSHXXX TSH: Device Code XXX: Inside Code Order Information Part Number Package Top Marking Quantity/Reel TMI3252SH SOT23-6 TSHXXX 3000 TMI3252SH devices are Pb-free and RoHS compliant. www.toll-semi.com www.suntosemi.com 2 TMI and SUNTO are the brands of TOLL microelectronic TMI3252SH Rev.1.0 – 2019.10 TMI3252SH 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 130 °C/W θJC Junction-to-case(top) thermal resistance 60 °C/W TMI and SUNTO are the brands of TOLL microelectronic TMI3252SH Rev. 1.0 – 2019.10 www.toll-semi.com www.suntosemi.com 3 TMI3252SH 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 18.5 19.3 19.8 V UVLO Rising Threshold 4.0 4.3 4.5 V UVLO Hysteresis 0.4 0.45 0.5 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 350 0.588 μA 5 10 μA 0.6 0.612 V High-Side Switch On-Resistance 140 mΩ Low-Side Switch On-Resistance 70 mΩ High-Side Switch Leakage Current VEN=0V, VLX=0V Switch Valley Current Limit Minimum Duty Cycle 2.5 On Time VIN=12V, VOUT=1.2V, IOUT=1A Oscillation Frequency 1 10 μA 3.0 3.5 A 90 120 160 ns 900 1000 1100 kHz Maximum Duty Cycle 80 % Minimum On-Time 80 ns Soft Start Time 0.8 ms Hiccup on Time 1 ms Hiccup Time Before Restart 4 ms EN Rising Threshold 1.0 1.10 1.2 V EN Falling Threshold 0.85 0.94 1.05 V 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. Note 4: Thermal shutdown threshold and hysteresis are guaranteed by design. www.toll-semi.com www.suntosemi.com 4 TMI and SUNTO are the brands of TOLL microelectronic TMI3252SH Rev.1.0 – 2019.10 TMI3252SH 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. TMI3252SH Block Diagram Operation Description Internal Regulator The TMI3252SH 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 TMI3252SH 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 TMI3252SH Rev. 1.0 – 2019.10 www.toll-semi.com www.suntosemi.com 5 TMI3252SH 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 TMI3252SH 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 42% of VREF, TMI3252SH 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 TMI3252SH hiccup mode is typically 5ms. 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 TMI3252SH VOUT FB R1 R2 Figure 2. Feedback Network www.toll-semi.com www.suntosemi.com 6 TMI and SUNTO are the brands of TOLL microelectronic TMI3252SH Rev.1.0 – 2019.10 TMI3252SH 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, 2A. The maximum inductor peak current is: I L 2 Under light load conditions below 100mA, larger inductance is recommended for improved efficiency. I L ( MAX ) = I LOAD + Selecting the Output Capacitor The output capacitor (Co1) 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: VOUT =  V   1 − OUT  8  f S  L  C2  VIN  VOUT 2 In the case of tantalum or electrolytic capacitors, the ESR dominates the impedance at the switching 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 TMI3252SH can be optimized for a wide range of capacitance and ESR values. TMI and SUNTO are the brands of TOLL microelectronic TMI3252SH Rev. 1.0 – 2019.10 www.toll-semi.com www.suntosemi.com 7 TMI3252SH Typical Performance Characteristics Efficiency Efficiency VOUT =3.3V, L=2.2μH, DCR=20mΩ VOUT =5V, L=2.2μH, DCR=30mΩ 100% 90% 90% 80% 80% Efficiency Efficiency 100% 70% 60% 60% 50% VIN=9V 50% VIN=12V 40% 30% 0.001 70% 0.1 1 Output Current (A) VIN=12V 40% VIN=16V 0.01 VIN=9V VIN=16V 30% 0.001 10 Efficiency 3.38 80% 3.36 Output Voltage(V) Efficiency 3.40 70% 60% 50% 10% 0.001 10 Line Regulation 90% VIN=9V 20% 1 VIN=12V, TA=25°C 100% 30% 0.1 Output Current (A) VOUT=1.2V, L=1.5μH, DCR=20mΩ 40% 0.01 3.34 3.32 3.30 3.28 3.26 VIN=12V 3.24 VIN=16V 3.22 Io=0A Io=1A 3.20 0.01 0.1 1 Output Current (A) 10 4 6 8 10 12 14 16 18 Input Voltage(V） Load Transient Load Transient VIN = 12V, VOUT = 3.3V, Io = 0A to 1A VIN = 12V, VOUT = 3.3V, Io = 1A to 2A VOUT=100mV/div AC coupled VOUT=100mV/div AC coupled Io=1A/div Io=1A/div Time: 200μs/div www.toll-semi.com www.suntosemi.com 8 Time: 200μs/div TMI and SUNTO are the brands of TOLL microelectronic TMI3252SH Rev.1.0 – 2019.10 TMI3252SH Typical Performance Characteristics(continued) Output Short Entry Output Short Recovery VIN =12V, VOUT = 3.3V, Io = 2A VIN=12V, VOUT = 3.3V, Io = 2A VIN=2V/div VIN=2V/div VOUT=2V/div VOUT=2V/div LX=10V/div LX=10V/div IL= 2A/div IL= 2A/div Time: 4ms/div Time: 4ms/div Input Power On Input Power Down VIN =12V, VOUT = 3.3V, Io = 2A VIN =12V, VOUT = 3.3V, Io = 2A VIN=5V/div VOUT=2V/div VIN=5V/div LX=10V/div VOUT=2V/div LX=10V/div IL=2A/div IL=2A/div Time: 800μs/div Time: 20ms/div EN Enable EN Disable VIN =12V, VOUT = 3.3V, Io = 2A VIN =12V, VOUT = 3.3V, Io = 2A EN=1V/div VOUT=2V/div EN=1V/div VOUT=2V/div LX=10V/div LX=10V/div IL=2A/div TMI and SUNTO are the brands of TOLL microelectronic TMI3252SH Rev. 1.0 – 2019.10 Time: 2ms/div IL=2A/div Time: 20μs/div www.toll-semi.com www.suntosemi.com 9 TMI3252SH 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 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 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 Figure 6. 12VIN, 1.8V Output (VFB=0.6V) www.toll-semi.com www.suntosemi.com 10 TMI and SUNTO are the brands of TOLL microelectronic TMI3252SH Rev.1.0 – 2019.10 TMI3252SH 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 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 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 20kΩ Cfb 20pF~ 100pF EN FB GND CO1 R2 59kΩ 22µF Figure 9. 12VIN, 1V Output (VFB=0.6V) TMI and SUNTO are the brands of TOLL microelectronic TMI3252SH Rev. 1.0 – 2019.10 www.toll-semi.com www.suntosemi.com 11 TMI3252SH 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. Top Layer Bottom Layer Figure 3. Sample of PCB Layout (TMI3252SH) www.toll-semi.com www.suntosemi.com 12 TMI and SUNTO are the brands of TOLL microelectronic TMI3252SH Rev.1.0 – 2019.10 TMI3252SH Package Information SOT23-6 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 TMI3252SH Rev. 1.0 – 2019.10 www.toll-semi.com www.suntosemi.com 13 TMI3252SH TAPE AND REEL INFORMATION TAPE DIMENSIONS: SOT23-6 REEL DIMENSIONS: SOT23-6 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 www.suntosemi.com 14 TMI and SUNTO are the brands of TOLL microelectronic TMI3252SH Rev.1.0 – 2019.10