HT7463A/HT7463B 52V/600mA, 1.25MHz/550kHz Asynchronous Step Down Converter Features General Description • Wide Input Voltage Range 4.5V to 52V The HT7463A/B is a current mode buck converter. With a wide input range from 4.5V to 52V, the HT7463A/B is suitable for a wide range of applications such as power conditioning from unregulated sources. Having a low internal switch typical RDSON value of 0.9Ω, the device has a good operating typical efficiency value of 85% and the added advantage of reduced junction temperature. The operating frequency is fixed at 1250/550kHz for the HT7463A/HT7463B respectively. The HT7463A allows the use of small external components while still being able to have low output voltage ripple. A soft-start function can be implemented using the enable pin and by connecting an external RC circuit allowing the user to tailor the soft-start time to a specific application. • 52V / 0.9Ω Internal Power MOSFET • 600mA Peak Output Current • Up to 90% Efficiency • 1.25MHz (HT7463A) and 550kHz (HT7463B) Fixed Operating Frequency • Ultra Low Shutdown Current < 1µA • Output Short Circuit Protection • Thermal Shutdown Protection • Package Type: SOT23-6 Applications • Power Meters • Distribution Power Systems • Battery Chargers • Pre-Regulator for Linear Regulators Application Circuit CB 0.1µF L1 22µH/47µH *3 HT7463A/B 1 2 3 SW GND VIN FB EN 4 R2 6kΩ / ±1% C3 0.1µF D1 6 CB VOUT=12V *1 5 C4 22µF *2 VIN On/Off Control C1 0.1µF C2 100µF R1 84kΩ / ±1% Note: *1. C4=330μF is recommended to achieve 1‰ output ripple requirement *2. Set R1=84kΩ and R2=16kΩ for VOUT=5V application *3. It’s recommended that L1=22μH for HT7463A and L1=47μH for HT7463B Rev. 1.10 1 June 10, 2015 HT7463A/HT7463B Block Diagram VIN EN Regulator UVLO 1.25MHz/550kHz Oscillator FB OCP VCC VREF Current Sense Amp. CB VCC VREF 0.9Ω Control Logic Current Comparator FB SW OTP 0.794V Error Amp. GND PWM Comparator SS/OSP Pin Assignment SOT23-6 SW VIN EN 6 5 4 463X 2 CB GND 3 FB 1 Top View X means A(1.25MHz)/or B(550kHz) Rev. 1.10 2 June 10, 2015 HT7463A/HT7463B Pin Descpription Pin Order Name Type Pin Discpription 1 CB I/O SW FET gate bias voltage. Connect the boot capacitor between CB and SW 2 GND G Ground terminal 3 FB I Feedback pin: Set feedback voltage divider ratio with VOUT = VFB (1+(R1/R2)) 4 EN I Logic level shutdown pin. Internal pull low resistor 5 VIN P Power supply 6 SW O Power FET output Absolute Maximum Ratings Parameter Value Unit VIN and SW -0.3 to +55 V EN -0.3 to (VIN+0.3) V CB above SW voltage +5.5 V FB -0.3 to +5.0 V Operating Temperature Range -40 to +85 °C Maximum Junction Temperature +150 °C Storage Temperature Range -65 to +160 °C Lead Temperature (Soldering 10sec) +300 °C Human Body Model 2000 V Machine Model 200 V Junction-to-Ambient Thermal Resistance, θJA 220 °C/W Junction-to-Case Thermal Resistance, θJC 110 °C/W ESD Susceptibility Recommended Operating Range Parameter Value Unit VIN 4.5 to 52 V SW and EN Up to 52 V Note that Absolute Maximum Ratings indicate limitations beyond which damage to the device may occur. Recommended Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee specified performance limits. Rev. 1.10 3 June 10, 2015 HT7463A/HT7463B Electrical Characteristics Symbol Parameter VIN=12V and Tj=+25°C, unless otherwise specified Test Condition Min Typ Max Unit Supply Voltage VIN Input Voltage VIN 4.5 — 52 V ICC Quiescent Current VEN=2.5V, VFB=1V — 0.7 1 mA IOFF Shutdown Current VEN=0V — 0.1 1 μA Buck Converter Output Voltage* VOUT fSW Switching Frequency FFB Fold-back Frequency 1.0 — 0.9×VIN V HT7463A, VFB=0.6V — 1000 1250 1500 kHz HT7463B, VFB=0.6V 440 550 660 kHz HT7463A, VFB=0V 90 105 — kHz HT7463B, VFB=0V 90 105 — kHz HT7463A — 90 — % HT7463B — 95 — % ns DMAX Maximum Duty Cycle TON(min) Minimum ON-Time — 100 — RDS(on) Switch-ON Resistance VEN=2.5V — 0.9 — Ω ISW(off) SW Leakage Current VEN=0V, VSW=0V, VIN=52V — 0.1 1 μA VFB Feedback Voltage 4.5V ≤ VIN ≤ 52V 0.778 0.794 0.81 V IFB(leak) Feedback Leakage Current VFB=3V — — 0.1 μA IEN EN Input Current VLH VHL — VEN=0V — 0.1 — μA VEN=52V — 16 — μA EN High Voltage Threshold 4.5V ≤ VIN ≤ 52V — — 2.3 V EN Low Voltage Threshold 4.5V ≤ VIN ≤ 52V 0.9 — — V Protections VUVLO+ Input Supply Turn ON Level UVLO+ — — 4.2 V VUVLO− Input Supply Turn OFF Level UVLO− 3.4 — — V — 1 — A — 150 — °C — 125 — °C IOCP Over Current Protection Threshold TSHD Thermal Shutdown Threshold TREC Thermal Recovery Temperature — OTP — Note: 1. MIN Output Voltage is restricted by Minimum ON-Time, 100ns. 2. MAX Output Voltage is restricted by Maximum Duty Cycle and Switch-ON Resistance. Rev. 1.10 4 June 10, 2015 HT7463A/HT7463B Typical Performance Characteristics VIN=18V, VOUT=12.5V, L=15/22µH for HT7463A and L=33/47µH for HT7463B, TA=25°C, unless otherwise noted Efficiency vs. Load (HT7463A, VOUT=12.5V) Efficiency vs. Load (HT7463B, VOUT=12.5V) Efficiency vs. Load (HT7463A, VOUT=5.7V) Efficiency vs. Load (HT7463B, VOUT=5.7V) Efficiency vs. Load (HT7463A, VOUT=3.3V) Efficiency vs. Load (HT7463B, VOUT=3.3V) 12.640 12.590 12.590 12.540 12.540 Vout (V) Vout (V) 12.640 12.490 12.440 12.440 15uH 22uH 12.390 1 5 10 50 33uH 47uH 12.390 12.340 12.340 80 125 200 300 400 500 600 Output Current (mA) Load Regulation (HT7463A, VOUT=12.5V) Rev. 1.10 12.490 1 5 10 50 80 125 200 300 400 500 600 Output Current (mA) Load Regulation (HT7463B, VOUT=12.5V) 5 June 10, 2015 HT7463A/HT7463B Typical Performance Characteristics (Continued) VIN=18V, VOUT=12.5V, L=22µH for HT7463A and L=47µH for HT7463B, TA=25°C, unless otherwise noted 5.860 5.810 5.810 5.760 5.760 Vout (V) Vout (V) 5.860 5.710 5.710 5.660 5.660 5.560 1 5 10 5.560 1 50 80 125 200 300 400 500 600 Output Current (mA) 10 50 80 125 200 300 400 500 600 Load Regulation (HT7463B, VOUT=5.7V) 3.330 3.320 3.320 3.310 3.310 Vout (V) 3.330 3.300 3.300 3.290 3.290 3.280 3.280 15uH 22uH 3.270 33uH 47uH 3.270 3.260 3.260 1 5 10 50 80 125 200 300 400 500 600 Output Current (mA) 1 Load Regulation (HT7463A, VOUT=3.3V) 5 10 50 80 125 200 300 400 500 600 Output Current (mA) Load Regulation (HT7463B, VOUT=3.3V) 12.515 12.510 12.510 12.505 12.505 Vout (V) Vout (V) 12.515 12.500 12.495 12.490 12.500 12.495 12.490 15uH 22uH 12.485 12.480 14 18 24 33uH 47uH 12.485 12.480 36 14 Vin (V) 18 24 36 Vin (V) Line Regulation (HT7463A, VOUT=12.5V, IOUT=300mA) Line Regulation (HT7463B, VOUT=12.5V, IOUT=300mA) 5.705 5.704 5.704 5.703 5.703 5.702 5.702 5.701 5.701 Vout (V) Vout (V) 5.705 5.700 5.699 5.700 5.699 5.698 5.698 5.697 5.697 15uH 22uH 5.696 5.695 8 12 Vin (V) 18 33uH 47uH 5.696 5.695 24 8 Line Regulation (HT7463A, VOUT=5.7V, IOUT=300mA) Rev. 1.10 5 Output Current (mA) Load Regulation (HT7463A, VOUT=5.7V) Vout (V) 33uH 47uH 5.610 15uH 22uH 5.610 12 Vin (V) 18 24 Line Regulation (HT7463B, VOUT=5.7V, IOUT=300mA) 6 June 10, 2015 3.315 3.315 3.314 3.314 3.313 3.313 3.312 3.312 3.311 3.311 Vout (V) Vout (V) HT7463A/HT7463B 3.310 3.310 3.309 3.309 3.308 3.308 15uH 22uH 3.307 3.306 3.307 8 12 18 33uH 47uH 3.306 3.305 3.305 24 8 Vin (V) Line Regulation (HT7463A, VOUT=3.3V, IOUT=300mA) 24 1200 Frequency (KHz) Current Limit (A) 18 1400 1 0.8 0.6 0.4 HT7463A HT7463B 0.2 0 1000 800 600 400 HT7463A HT7463B 200 0 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 0 VEN (V) IOCP vs. VEN (HT7463A and HT7463B) 0.1 0.2 0.3 0.4 Vfb (V) 0.5 0.6 0.7 fSW vs. VFB (HT7463A and HT7463B) 1600 1600 1400 1200 1200 Frequency (KHz) 1400 1000 OCP (mA) Vin (V) Line Regulation (HT7463B, VOUT=3.3V, IOUT=300mA) 1.2 800 600 400 HT7463A HT7463B 200 0 -40 -20 0 25 50 Temperature (℃) 85 100 1000 800 600 400 HT7463A HT7463B 200 0 -40 125 IOCP vs. TEMP (HT7463A and HT7463B) -20 0 25 50 Temperature (℃) 85 100 125 fSW vs. TEMP (HT7463A and HT7463B) 1 0.805 0.9 0.8 Quiescent (mA) 0.8 0.795 VFB (V) 12 0.79 0.785 0.78 -40 -20 0 25 50 Temperature (℃) 85 100 0.5 0.4 0.3 HT7463A HT7463B 0.1 0 125 -40 VFB vs. TEMP (HT7463A and HT7463B) Rev. 1.10 0.6 0.2 HT7463A HT7463B 0.775 0.7 -20 0 25 50 Temperature (℃) 85 100 125 ICC vs. TEMP (HT7463A and HT7463B) 7 June 10, 2015 HT7463A/HT7463B Output Ripple (HT7463A, IOUT=400mA) Output Ripple (HT7463B, IOUT=400mA) Output Ripple (HT7463A, IOUT=125mA) Output Ripple (HT7463B, IOUT=125mA) Load Transient (HT7463A, IOUT=50mA to 200mA) Load Transient (HT7463B, IOUT=50mA to 200mA) Power Up (HT7463A, VIN=52V, IOUT=500mA) Power Up (HT7463B, VIN=52V, IOUT=500mA) Rev. 1.10 8 June 10, 2015 HT7463A/HT7463B Power Down (HT7463A, VIN=52V, IOUT=500mA) Power Down (HT7463B, VIN=52V, IOUT=500mA) Output Short (HT7463A, IOUT=500mA) Output Short (HT7463B, IOUT=500mA) Short Recovery (HT7463A, IOUT=500mA) Short Recovery (HT7463B, IOUT=500mA) Enable ON (HT7463A, IOUT=500mA) Enable ON (HT7463B, IOUT=500mA) Rev. 1.10 9 June 10, 2015 HT7463A/HT7463B Enable OFF (HT7463A, IOUT=500mA) Enable OFF (HT7463B, IOUT=500mA) Functional Description Output Voltage Setup Protection Features The external resistor divider sets the output voltage, for details see the Application Circuit. The feedback resistor, R1, also sets the feedback loop bandwidth with the internal compensation capacitor. R2 is calculated using the following equation: The devices include dedicated protection circuitry which is fully active during normal operation for full device protection. The thermal shutdown circuitry turns off power to the device when the die temperature reaches excessive levels. The UVLO comparator protects the power device during supply power startup and shutdown to prevent operation at voltages less than the minimum input voltage. The HT7463A/B also features a shutdown mode decreasing the supply current to approximately 0.1μA. R2=R1/((VOUT/0.794V)-1) Ω Rev. 1.10 10 June 10, 2015 HT7463A/HT7463B Recommended Component Values CB 0.1µF L1 22µH/47µH * HT7463A/B 1 2 3 C3 0.1µF D1 6 CB SW GND VIN FB EN 4 VOUT 5 C4 22µF VIN On/Off Control C1 0.1µF C2 100µF R1 CC R2 0.1uF (Optional) Note: * It’s recommended that L1=22μH for HT7463A and L1=47μH for HT7463B. Rev. 1.10 VOUT (V) R1 (kΩ) R2 (kΩ) 3.3 51 (1%) 16 (1%) 5.0 82 (1%) 15 (1%) 12.5 91 (1%) 6.2 (1%) 11 June 10, 2015 HT7463A/HT7463B Component Selection Guide Frequency Fold-back Function The devices include a frequency fold-back function to prevent situations of over current when the output is shorted. It efficiently reduces overheating even if the output is shorted. This function is implemented by changing the switching frequency according the feedback voltage, V FB. When the output node is shorted, the device will reduce the frequency to 105kHz for the HT7463A/HT7463B respectively resulting in a clamped input current. The HT7463A/ HT7463B operates at a frequency of 1250/550kHz under normal conditions and the feedback voltage is about 0.794V. 1400 Use an inductor with a DC current rating at least 25% percent higher than the maximum load current for most applications. The DC resistance of the inductor is a key parameter affecting efficiency. With regard to efficiency, the inductor’s DC resistance should be less than 200mΩ. For most application, the inductor value can be calculated from the following equation. L= 1000 800 600 400 Input Capacitor HT7463A HT7463B 200 0 0 0.1 0.2 0.3 0.4 0.5 0.6 A low ESR ceramic capacitor (CIN) is needed between the VIN pin and GND pin. Use ceramic capacitors with X5R or X7R dielectrics for their low ESRs and small temperature coefficients. For most applications, a 2.2μF- 10µF capacitor will suffice. 0.7 VFB (V) Start-up Function The device EN pin in conjunction with an RC filter is used to tailor the soft-start time to specific application requirements. When a voltage applied to the EN pin is between 0V and 2.3V, the device will cause the cycle-by-cycle current limit in the power stage to be modulated for a minimum current limit at 0V up to a the rated current limit at 2.3V. Thus, the output rise time and inrush current at startup are controlled. 1.2 Current Limit (A) 1 Vout × (VIN − Vout ) VIN × Iripple × fsw A higher value of ripple current reduces the inductance value, but increases the conductance loss, core loss, and current stress for the inductor and switch devices. A suggested choice is for the inductor ripple current to be 30% of the maximum load current. FREQUENCY FOLD-BACK 1200 Frequency (KHz) Inductor Output Capacitor The selection of COUT is driven by the maximum allowable output voltage ripple. Use ceramic capacitors with X5R or X7R dielectrics for their low ESR characteristics. Capacitors in the range of 22μF to 100μF are a good starting point with an ESR of 0.1Ω or less. Schottky Diode VEN vs. Current Limit The breakdown voltage rating of the diode should be higher than the maximum input voltage. The current rating for the diode should be equal to the maximum output current to ensure the best reliability in most applications. In this case it is possible to use a diode with a lower average current rating, however the peak current rating should be higher than the maximum load current. 0.8 0.6 0.4 HT7463A HT7463B 0.2 0 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Bootstrap Capacitor VEN (V) A 0.1μF ceramic capacitor or larger is recommended for the bootstrap capacitor. Generally a 0.1μF to 1μF value can be used to ensure sufficient gate drive for the internal switches and a consistently low RDSON. Rev. 1.10 12 June 10, 2015 HT7463A/HT7463B Layout Consideration Guide Thermal Considerations To reduce problems with conducted noise, there are some important points to consider regarding the PCB layout. The maximum power dissipation depends on the thermal resistance of the IC package, the PCB layout, the rate of the surrounding airflow and the difference between the junction and ambient temperature. The maximum power dissipation can be calculated by the following formula: • Ensure all feedback connections are short and direct. Place the feedback resistors and compensation components as close to the FB pin as possible. PD(MAX) = (TJ(MAX) – TA) / θJA • The input bypass capacitor must be placed close to the VIN pin. where TJ(MAX) is the maximum junction temperature, TA is the ambient temperature and qJA is the junctionto-ambient thermal resistance of the IC package (220oC/W for SOT23-6) • The inductor, schottky diode and output capacitor trace should be as short as possible to reduce conducted and radiated noise and increase overall efficiency. For maximum operating rating conditions, the maximum junction temperature is 150oC. However, it is recommended that the maximum junction temperature does not exceed 125oC in normal operation to maintain reliability. The derating curve for maximum power dissipation is as follows: • Keep the power ground connection as short and wide as possible. Maximum Power Dissipation (W) 0.6 0.568W 0.5 0.4 0.3 0.2 0.1 0 0 25 50 75 100 125 150 Ambient Temperature (oC) Rev. 1.10 13 June 10, 2015 HT7463A/HT7463B Package Information Note that the package information provided here is for consultation purposes only. As this information may be updated at regular intervals users are reminded to consult the Holtek website for the latest version of the package information. Additional supplementary information with regard to packaging is listed below. Click on the relevant section to be transferred to the relevant website page. • Further Package Information (include Outline Dimensions, Product Tape and Reel Specifications) • Packing Meterials Information • Carton information Rev. 1.10 14 June 10, 2015 HT7463A/HT7463B SOT23-6 Outline Dimensions Symbol A Nom. Max. — — 0.057 A1 — — 0.006 A2 0.035 0.045 0.051 b 0.012 — 0.020 C 0.003 — 0.009 D — 0.114 BSC — E — 0.063 BSC — e — 0.037 BSC — e1 — 0.075 BSC — H — 0.110 BSC — L1 — 0.024 BSC — θ 0° — 8° Symbol Rev. 1.10 Dimensions in inch Min. Dimensions in mm Min. Nom. Max. A — — 1.45 A1 — — 0.15 A2 0.90 1.15 1.30 b 0.30 — 0.50 C 0.08 — 0.22 D — 2.90 BSC — E — 1.60 BSC — e — 0.95 BSC — e1 — 1.90 BSC — H — 2.80 BSC — L1 — 0.60 BSC — θ 0° — 8° 15 June 10, 2015 HT7463A/HT7463B Copyright© 2015 by HOLTEK SEMICONDUCTOR INC. The information appearing in this Data Sheet is believed to be accurate at the time of publication. However, Holtek assumes no responsibility arising from the use of the specifications described. The applications mentioned herein are used solely for the purpose of illustration and Holtek makes no warranty or representation that such applications will be suitable without further modification, nor recommends the use of its products for application that may present a risk to human life due to malfunction or otherwise. Holtek's products are not authorized for use as critical components in life support devices or systems. Holtek reserves the right to alter its products without prior notification. For the most up-to-date information, please visit our web site at http://www.holtek.com.tw. Rev. 1.10 16 June 10, 2015