NCP1589L Low Voltage Synchronous Buck Controller with Light Load Efficiency and Transient Enhancement The NCP1589L is a low cost PWM controller designed to operate from a 5 V or 12 V supply. This device is capable of producing an output voltage as low as 0.8 V and converting voltage from as low as 2.5 V. It is easy to operate and provides an optimal level of integration to reduce size and cost of the power supply. It operates in Ramp Pulse Modulation mode for superior load step and release response. In addition to fast transient response, it also includes a 1.5 A gate driver design and light load efficiency features such as adaptive non−overlap circuitry and diode emulation. It normally operates at a range of 200−500 kHz in continuous current conduction mode, which reduces with current at light load for further power saving. Protection features include programmable overcurrent protection, output overvoltage and undervoltage protection and input undervoltage lockout (UVLO). VCC Range from 4.5 V to 13.2 V Adjustable Operating frequency Boost Pin Operates to 35 V Ramp Pulse Modulation Control Precision 0.8 V Internal Reference Adjustable Output Voltage Internal 1.5 A Gate Drivers 80% Max Duty Cycle Input Under Voltage Lockout Programmable Current Limit Adaptive Diode Mode Emulation in Light Load This is a Pb−Free Device August, 2013 − Rev. 2 1589L A L Y W G = Specific Device Code = Assembly Location = Wafer Lot = Year = Work Week = Pb−Free Device BOOT 1 10 PGOOD LX 2 9 VORPM UG 3 8 FB LG 4 7 COMP/DIS GND 5 6 VCC Flag (Top View) ORDERING INFORMATION Graphics Cards Desktop Computers Servers / Networking DSP & FPGA Power Supply DC−DC Regulator Modules © Semiconductor Components Industries, LLC, 2013 1589L ALYWG G DFN10 CASE 485C PIN CONNECTIONS Applications • • • • • MARKING DIAGRAM (Note: Microdot may be in either location) Features • • • • • • • • • • • • http://onsemi.com Device Package Shipping† NCP1589LMNTWG DFN10 (Pb−Free) 3000 / Tape & Reel †For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8011/D. 1 Publication Order Number: NCP1589L/D NCP1589L VCC = 4.5 V − 13.2 V VBST = 4.5 V − 15 V VIN = 2.5 V − 19 V VCC BOOT PGOOD COMP/DIS UG R2 VOUT LX C2 FB LG FLAG ROCSET C1 GND VORPM C3 R4 R1 R3 R9 R10 GND Figure 1. Typical Application Diagram PGOOD PGOOD MONITOR OV and UV VORPM 9 0.8 V (Vref) ±10% of Vref ±25% of Vref POR UVLO 8 − − + 0.8 V (Vref) S PWM OUT Q + VCC 1 BOOT 3 UG 2 LX 4 LG 5 GND − RPMSET RAMP + LX COMP VPRM COMP/DIS 6 VOCP − FAULT R + + LATCH FAULT FB 10 2V − VORPM 7 FAULT LX Figure 2. Detailed Block Diagram http://onsemi.com 2 AZCD logic VCC NCP1589L PIN FUNCTION DESCRIPTION Pin No. Symbol Description 1 BOOT Supply rail for the floating top gate driver. To form a boost circuit, use an external diode to bring the desired input voltage to this pin (cathode connected to BOOT pin). Connect a capacitor (CBOOT) between this pin and the LX pin. Typical values for CBOOT range from 0.1 mF to 1 mF. Ensure that CBOOT is placed near the IC. 2 LX Switch node pin. This is the reference for the floating top gate driver. Connect this pin to the source of the top MOSFET. Also used for low side MOSFET RDS(on) current detection and diode emulation. 3 UG Top gate MOSFET driver pin. Connect this pin to the gate of the top N−channel MOSFET. 4 LG Bottom gate MOSFET driver pin. Connect this pin to the gate of the bottom N−channel MOSFET. Also used to set the overcurrent limit. 5 GND IC ground reference. All control circuits are referenced to this pin. Connect to FLAG. 6 VCC Supply rail for the internal circuitry. Operating supply range is 4.5 V to 13.2 V. Decouple with a 1 mF capacitor to GND. Ensure that this decoupling capacitor is placed near the IC. Also low−side MOSFET drive voltage. 7 COMP/DIS Compensation Pin. This is the output of the error amplifier (EA) and the non−inverting input of the PWM comparator. Use this pin in conjunction with the FB pin to compensate the voltage−control feedback loop. Pull this pin low for disable. 8 FB 9 VORPM Output voltage information for RPM threshold 10 PGOOD Power Good output. Pulled Low if VFB is outside ±10% of 0.8 V Vref. This pin is the inverting input to the error amplifier. Use this pin in conjunction with the COMP pin to compensate the voltage−control feedback loop. Connect this pin to the output resistor divider (if used) or directly to Vout. ABSOLUTE MAXIMUM RATINGS Pin Name Symbol VMAX VMIN VCC 15 V −0.3 V BOOT 35 V wrt/GND 40 V < 100 ns 15 V wrt/LX −0.3 V −0.3 V −0.3 V Switching Node (Bootstrap Supply Return) LX 35 V 40 V for < 100 ns −5 V −10 V for < 200 ns High−Side Driver Output (Top Gate) UG 30 V wrt/GND 15 V wrt/LX 40 V for < 100 ns −0.3 V wrt/LX −5 V for < 200 ns Low−Side Driver Output (Bottom Gate) LG 15 V −0.3 V −5 V for < 200 ns Feedback, VORPM FB, VORPM 6.0 V −0.3 V COMP/DIS COMP/DIS 5.5 V −0.3 V PGOOD 7V −0.3 V Symbol Value Unit Thermal Resistance, Junction−to−Ambient RqJA 165 °C/W Thermal Resistance, Junction−to−Case RqJC 45 °C/W Operating Junction Temperature Range TJ 0 to 150 °C Operating Ambient Temperature Range TA 0 to 95 °C Storage Temperature Range Tstg −55 to +150 °C Moisture Sensitivity Level MSL 1 − Main Supply Voltage Input Bootstrap Supply Voltage Input PGOOD MAXIMUM RATINGS Rating Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. http://onsemi.com 3 NCP1589L ELECTRICAL CHARACTERISTICS (0°C < TA < 95°C; 4.5 V < [BOOT−LX] < 13.2 V, 4.5 V < BOOT < 30 V, 0 V < LX < 21 V, CTG = CBG = 1.0 nF, for min/max values unless otherwise noted.) Conditions Characteristic VCC Input Voltage Range BOOT Voltage Range 13.2 V wrt LX dV/dt on VCC Min Typ Max Unit 4.5 13.2 V 4.5 30 V −10 10 V/ms 1.0 % 3.8 mA 100 mA VREF AND ERROR AMPLIFIER Vref Reference Voltage Output Voltage Accuracy Reference and Error Amplifier Excluding External Resistive Divider Tolerance 0.8 −1.0 V SUPPLY CURRENT VCC Quiescent Supply Current No Switching, VCC = 13.2 V BOOT Quiescent Current No Switching 2.5 0.1 UNDERVOLTAGE LOCKOUT VCC UVLO Threshold VCC Rising 4.4 V VCC UVLO Threshold VCC Falling 4.0 V VCC UVLO Hysteresis VCC Rising or VCC Falling 400 mV Ramp Slope 0.5 V/ms Ramp−Amplitude Voltage 1.50 V 0 % SWITCHING REGULATOR Minimum Duty Cycle Maximum Duty Cycle 70 LG Minimum on Time 200 83 92 % 350 ns ERROR AMPLIFIER 80 Open Loop DC Gain (Note 1) Output Source Current Output Sink Current Vfb < 0.8 V Vfb > 0.8 V 120 dB 2.0 2.0 mA Unity Gain Bandwidth (Note 1) 15 MHz Disable Threshold 0.7 Output Source Current During Disable 0.8 0.9 V 10 40 mA GATE DRIVERS Upper Gate Source BOOT − LX = 5 V Upper Gate Sink BOOT − LX = 5 V 1.5 A 1.8 W Lower Gate Source VCC = 5 V Lower Gate Sink VCC = 5 V 1.2 UG Falling to LG Rising Delay Tdead1 (Note 1) VCC = 12 V, UG−LX < 1.0 V, LG > 1.0 V Only Valid for CCM Operating Mode 20 30 ns LG Falling to UG Rising Delay Tdead2 (Note 1) VCC = 12 V, LG < 1.0 V, UG > 1.0 V Only Valid for CCM Operating Mode 20 30 ns Unbiased, BOOT − LX = 0 45 kW 45 kW UG Internal Resistor to LX LX Internal Resistor to GND 1.5 A W SOFT−START Soft−Start Time Enable to Soft−Start Delay (Note 1) VCC > 4.5 V, COMP w Disable Threshold VCC > 4.5 V, COMP Rises and Crosses Disable Threshold 1. Guaranteed by design but not tested in production. http://onsemi.com 4 2.0 2.6 ms 500 ms NCP1589L ELECTRICAL CHARACTERISTICS (0°C < TA < 95°C; 4.5 V < [BOOT−LX] < 13.2 V, 4.5 V < BOOT < 30 V, 0 V < LX < 21 V, CTG = CBG = 1.0 nF, for min/max values unless otherwise noted.) Characteristic Conditions Min Typ Max Unit 0.4 V 880 902 mV POWER GOOD INCLUDING OVP AND UVP THRESHOLD Output Voltage Logic Low, Sinking 4 mA Overvoltage until PGOOD goes low Undervoltage until PGOOD goes low 698 720 mV PGOOD High Upper Limit Hysteresis 16 mV PGOOD High Lower Limit Hysteresis 16 mV OVP Threshold to Part Disable 950 1000 1030 mV UVP Threshold to Part Disable 570 600 630 mV 1.0 ms 350 ns 40 ns Power Good Delay (Note 1) ZERO CURRENT DETECTION (LX Pin) LX > 50 mV, LG on time Zero Current Detection Blank Timer after TG < 1.0 V Capture Time for LX Voltage (Note 1) 200 250 Time to Capture LX Voltage Once LG is < 1.0 V ZERO CURRENT Vth ADJUSTMENT DETECTION (LX Pin) Negative LX Detection Voltage Vbdls 200 300 400 mV Positive LX Detection Voltage Vbdhs 0.2 0.5 1.0 V Time for Vth Adjustment and Settling Time 300 kHz 3.0 Zero Current Detection Blank Timer after LG < 1.0 V (Note 1) Blanking Time After LG is < 1.0 V Initial Negative Current Detection Threshold Voltage Setpoint (Note 1) LX−GND, Includes $2 mV Offset Range 3.7 ms 40 ns −5.0 −3.0 −1.0 mV −16 0 15 mV Sourced from LG pin, before SS 9.5 10 10.5 mA VCC > 4.5 V, Roscset = 60 kW 1.0 5.0 ms Vth Adjustable Range (Note 1) OVERCURRENT PROTECTION OC Current Source OCP Programming Time 1. Guaranteed by design but not tested in production. Phase Ugate to Phase 1V Lgate Tdead1 Tdead2 Figure 3. Dead Time Definition http://onsemi.com 5 NCP1589L APPLICATIONS INFORMATION Overcurrent Protection (OCP) from 0 to 2.5 V in 4.2 ms; however if the output capacitors already has 1.2 V voltage, the NCP1589L will not discharge the capacitors, instead the soft−start sequence will begin at 1.2 V and then ramp the output up to 2.5 V. The NCP1589L monitors the voltage across the low side MOSFET and used this information to determine if there is excessive output current. The voltage across the low side MOSFET is measured from the LX pin when it is conducted, and is referenced to ground. The overcurrent measurement is timed to occur at the end of the low side MOSFET conduction period. If the voltage drop across the bottom MOSFET exceeds the overcurrent protection threshold, then an internal counter is triggered and incremented. If the voltage drop does not exceed the threshold for the next cycle, the internal counter will be reset. The NCP1589L will latch the over current protection fault condition after 4 consecutive cycles of overcurrent events. When the NCP1589L latches an overcurrent protection fault, both the high side and low side MOSFETs are turned off. To reset the overcurrent protection fault, the power to the VCC pin must be cycled. The overcurrent threshold can be set externally, by varying the ROCSET resistor shunted from low side gate pin to ground. During power on reset, after the VCC and BOOT pins both pass the undervoltage lockout threshold, the NCP1589L will source a 10 mA current from LG pin through the ROCSET resistor and produce a voltage. This voltage will be sampled and locked by the device as the overcurrent protection threshold. For example, if ROCSET is set to 10 kW, the 10 mA of current will yield a 100 mV threshold, and if the voltage across the low side MOSFET exceeds 100 mV at the end of the its conduction period, an overcurrent event will be detected. The OCP threshold is only associated with power on reset, and won’t be wiped out by pulling COMP pin down (disabling the part). If the ROCSET resistor is not present, the overcurrent protection threshold will max out at 640 mV. The recommended range for ROCSET is 5 kW to 60 kW which yields a threshold voltage range of 50 mV to 600 mV. Power Good The PGOOD pin is an open drain connection, with an active high output to signal the condition of the converter. PGOOD is pulled low during soft−start cycle, and if there is overvoltage or undervoltage fault. If the voltage on the FB pin is within ±10% of Vref (800 mV) then the PGOOD pin will not be pulled low. The PGOOD pin does not have an internal pull-up resistor. Overvoltage Protection (OVP) If the voltage on the FB pin exceeds the overvoltage threshold (1000 mV, 125% of Vref), the NCP1589L will latch an overvoltage fault. During an overvoltage fault event the UG pin will be pulled low, and the LG pin will stay high until the voltage on the FB pin goes below Vref/2 (400 mV). If the overvoltage fault condition stays, the NCP1589L will continue drive the LG pin, LG will go high if FB exceeds 1000 mV, then go low when FB is below 400 mV. The power of the NCP1589L needs to be cycled up to clear the overvoltage fault. Undervoltage Protection (UVP) If the voltage on the FB pin falls below the undervoltage threshold after the soft−start cycle completes, then the NCP1589L will latch an undervoltage fault. During an undervoltage fault, both the UG and LG pins will be pulled low. Toggling power or COMP pin will reset the undervoltage protection unit. VORPM (RPM threshold) The NCP1589L runs in RPM mode, its switching frequency is controlled by COMP ripple voltage and RPM threshold. The VORPM pin is connected to the output voltage through an external divider. This voltage value is proportional to the output voltage and sets the RPM threshold voltage internally with input voltage information obtained through the switch node. The internal RPM threshold voltage (DTH) is a function of both Vout and Vin. Internal Soft−Start To prevent excess inrush current during startup, the NCP1589L uses a calibrated current source with an internal soft−start capacitor to ramp the reference voltage from 0 V to 800 mV over a period of around 4 ms. The soft−start ramp generator will reset if the input power supply voltages reach the undervoltage lockout threshold, or if the NCP1589L is disabled by having the COMP pin pulled low. DTH + V out R9 R10)R9 V in V ramp ) V offset (eq. 1) Where R9/R10 (Figure 1) is the input voltage divider of VORPM pin Vramp is the internal ramp amplitude, Voffset is the offset voltage of the threshold. Each time when COMP voltage exceeds RPM threshold voltage, an internal ramp signal is started and UG is driven high. When the internal ramp intercepts with COMP voltage, the UG pin is reset low. The NCP1589L system operates at pseudo-fixed frequency in continuous current Startup into a Precharged Load During a startup, the NCP1589L will detect the residual charge on the output capacitors. Instead of fully discharging the capacitors, the soft−start will begin from the precharged output voltage level. For example, if the NCP1589L is configured to provide a regulated output voltage of 2.5 V, the normal soft−start sequence will ramp the output voltage http://onsemi.com 6 NCP1589L the minimum amount of diode conduction period to further reduce the converter power consumption in the light load condition. conduction mode. The output frequency can be determined by the following equation: F SW + ǒ k1 Ramp_slope R9 V out R10)R9 V Ǔ 1 1 ) k2 V ramp ) V offset in V out V in Feedback Voltage The NCP1589L allows the output voltage to be adjusted from 0.8 V to 5 V via an external resistor divider network (R1, R4 in Figure 1). The controller will try to maintain 0.8 V at the FB pin. Thus, if a resistor divider circuit was placed across the feedback pin to Vout, the controller will regulate the output voltage in proportion to the resistor divider ratio in order to maintain 0.8 V at the FB pin. The relation between the resistor divider network and the output voltage is show in the following equation: (eq. 2) Where k1, k2 is an internal trimmed value; by default, k1 = 1, k2 = 0, Ramp_slope = 0.5 V/ms, Vramp = 1.5 V, Voffset = 20 mV. Light Load Operation In continuous current conduction mode, the operating frequency of the NCP1589L is almost constant. In light load, it runs in a discontinuous current mode with a scaled-down frequency as a function of the load current. Internal zero current detection threshold will change adaptively to ensure R4 + R1 ǒ 4.4 V ǒ 4.0 V VCC Internal UVLO Fault 1.3 V COMP LG UG VOUT 0.8 V FB PGOOD POR Ǔ V ref + R1 V out * V ref OCP Soft−Start Time Programming Time NORMAL Figure 4. Typical Startup Sequence http://onsemi.com 7 0.8 V V out * 0.8 V Ǔ (eq. 3) NCP1589L PACKAGE DIMENSIONS DFN10, 3x3, 0.5P CASE 485C ISSUE C D PIN 1 REFERENCE 2X 2X L1 ÇÇÇ ÇÇÇ ÇÇÇ 0.15 C EDGE OF PACKAGE A B E DETAIL A Bottom View (Optional) MOLD CMPD 0.15 C (A3) DETAIL B 0.10 C A1 A 10X SIDE VIEW A1 D2 L 1 C DETAIL A e A3 DETAIL B Side View (Optional) SEATING PLANE 0.08 C 10X ÉÉÉ ÉÉÉ EXPOSED Cu TOP VIEW NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M, 1994. 2. CONTROLLING DIMENSION: MILLIMETERS. 3. DIMENSION b APPLIES TO PLATED TERMINAL AND IS MEASURED BETWEEN 0.25 AND 0.30 MM FROM TERMINAL. 4. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS. 5. TERMINAL b MAY HAVE MOLD COMPOUND MATERIAL ALONG SIDE EDGE. MOLD FLASHING MAY NOT EXCEED 30 MICRONS ONTO BOTTOM SURFACE OF TERMINAL b. 6. DETAILS A AND B SHOW OPTIONAL VIEWS FOR END OF TERMINAL LEAD AT EDGE OF PACKAGE. 7. FOR DEVICE OPN CONTAINING W OPTION, DETAIL B ALTERNATE CONSTRUCTION IS NOT APPLICABLE. SOLDERING FOOTPRINT* 5 DIM A A1 A3 b D D2 E E2 e K L L1 MILLIMETERS MIN MAX 0.80 1.00 0.00 0.05 0.20 REF 0.18 0.30 3.00 BSC 2.40 2.60 3.00 BSC 1.70 1.90 0.50 BSC 0.19 TYP 0.35 0.45 0.00 0.03 2.6016 10X E2 K 10 10X 0.10 C A B 0.05 C 1.8508 2.1746 6 3.3048 b BOTTOM VIEW NOTE 3 10X 0.5651 10X 0.5000 PITCH 0.3008 DIMENSIONS: MILLIMETERS *For additional information on our Pb−Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of SCILLC’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. 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