Ordering number : ENA1684 LV5749NV Bi-CMOS LSI 1-channel Step-down Switching Regulator http://onsemi.com Application The LV5749NV is a 1-channel step-down switching regulator. Functions • 1 channel step-down switching regulator controller. • Load-independent soft start circuit. • ON/OFF function. • Built-in pulse-by-pulse OCP circuit. It is detected by using ON resistance of an external MOS. • Synchronous rectification. • Current mode control. • Synchronous drive by external signal. Specifications Absolute Maximum Ratings at Ta = 25°C Parameter supply voltage Symbol Conditions Ratings VIN max Unit 45 Mounted on a specified board. * V Allowable Power dissipation Pd max 0.74 W Operating temperature Topr -40 to +85 °C Storage temperature Tstg -55 to +150 °C * : When mounted on the specified printed circuit board (114.3mm × 76.1mm × 1.6mm), glass epoxy 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. Recommended Operating Range at Ta = 25°C Parameter Supply voltage range Symbol VIN Error amplifier input voltage Semiconductor Components Industries, LLC, 2013 August, 2013 Conditions Ratings Unit 8.5 to 42 V 0 to 1.6 V 82510 SY 20100312-S00001 No.A1684-1/6 LV5749NV Electrical Characteristics at Ta = 25°C, VIN = 12V Parameter Symbol Ratings Conditions min typ Unit max Reference voltage block Internal reference voltage Vref Including offset of E/A 0.654 0.67 0.686 V 5V power supply VDD IOUT = 0 to 5mA 4.7 5.2 5.7 V 110 125 140 kHz Triangular waveform oscillator block Oscillation frequency FOSC RT = 220kΩ Frequency variation FOSC DV VIN = 8.5 to 42V 1 % ON/OFF circuit block IC start-up voltage VEN on 2.5 3.0 3.5 V IC off voltage VEN off 1.1 1.3 1.5 V 4 5 6 Soft start circuit block Soft start source current ISS SC EN > 3.5V Soft start sink current ISS SK EN < 1V, VDD=5V 2 μA mA UVLO circuit block UVLO lock release voltage VUVLO UVLO hysteresis VUVLO H 7.5 8.0 8.5 V 0.7 V 5 μA OCP circuit block OCP charge current IOCP Error amplifier Input bias current IEA IN Error amplifier transconductance GEA 1000 Sink output current IEA OSK FB = 1.0V Source output current IEA OSC FB = 0V Current detection amplifier gain GISNS 1400 100 nA 1800 μA/V -100 μA 100 μA 1.5 Over current limiter circuit block Reference current 1 ILIM1 MODE = L (GND) -10% 18.5 +10% μA Reference current 2 ILIM2 MODE = H (VIN) -10% 37.0 +10% μA Over current detection comparator VLIM OFS -5 +5 mV VIN-0.45 VIN V V offset voltage Over current detection comparator common mode input range PWM comparator Input threshold voltage Vt max Duty cycle = DMAX 0.9 1.0 1.1 (fosc = 125kHz) Vt0 Duty cycle = 0% 0.4 0.5 0.6 V Maximum ON duty DMAX 80 85 90 % Output block Output stage ON resistance RONH 5 Ω RONL 5 Ω (the upper side) Output stage ON resistance (the under side) Output stage ON current IONH 240 mA IONL 240 mA (the upper side) Output stage ON current (the under side) The whole device Standby current ICCS EN < 1V Mean consumption current ICCA EN > 3.5V 10 3 μA mA No.A1684-2/6 LV5749NV Package Dimensions unit : mm (typ) 3178B Pd max -- Ta 1.0 0.5 6.4 9 4.4 16 Allowable power dissipation, Pd max -- W 5.2 1 8 0.65 0.15 0.22 1.5max (0.33) Specified circuit board : 114.3 ×76.1× 1.6mm3 glass epoxy board 0.8 0.7 0.6 0.4 0.38 0.2 -20 (1.3) 0 -40 0 20 40 60 80 100 0.1 Ambient temperature, Ta -- C SANYO : SSOP16(225mil) Pin Assignment 16 SS FB 1 COMP 2 15 ILIM EN 3 14 VIN RT 4 13 OCP LV5749NV SYNC 5 12 MODE SW 6 11 GND CBOOT 7 10 VDD HDRV 8 9 LDRV Top view No.A1684-3/6 LV5749NV Block Diagram VIN 14 REFERENCE VOLTAGE 5V REGULATOR MODE 12 UVLO 5μA OCP 13 1.25V + OCP Comp1 OSP LOGIC + OCP Comp2 VCC ILIM 15 MODE L 18.5μA MODE H 37μA 5μA S Q R SD SS 16 FB 1 0.67V COMP 2 + + - 7 CBOOT + Current Amp SAW WAVE OSCILLATOR 8 HDRV DMAX = 90% 1.0V 0.5V Err Amp 6 SW + PWM Comp CONTROL Logic 5V 10 VDD 9 LDRV shut down(SD) 4 5 RT SYNC 11 GND 3 EN Pin Function Pin No. Pin name 14 VIN Description Power supply pin. This pin is monitored by UVLO function. When the voltage of this pin becomes 7.7V or more by UVLO function, The IC starts and the soft start function operates. 11 GND Ground pin. Each reference voltage is based on the voltage of the ground pin. 10 VDD Power supply pin for an external the lower MOS-FET gate drive. 7 CBOOT Bootstrap capacity connection pin. This pin becomes a GATE drive power supply of an external NchMOSFET. Connect a bypath capacitor between CBOOT and SW. 6 SW Pin to connect with switching node. The source of NchMOSFET connects to this pin. 5 SYNC External synchronous signal input pin. 9 LDRV An external the lower MOSFET gate drive pin. 8 HDRV An external the upper MOSFET gate drive pin. 1 FB Error amplifier reverse input pin. By operating the converter, the voltage of this pin becomes 0.67V. The voltage in which the output voltage is divided by an external resistance is applied to this pin. 2 COMP Error amplifier output pin. Connect a phase compensation circuit between this pin and GND. 16 SS Pin to connect a capacitor for soft start. A capacitor for soft start is charged by using the voltage of about 5μA. This pin ends the soft start period by using the voltage of about 1.1V and the frequency fold back function becomes active. 15 ILIM Reference current pin for current detection. The sink current of about 20μA flows to this pin when Low level (GND) is set to the MODE pin. Also, the sink current of about 40μA flows to this pin when High level (VIN) is set to the MODE pin. When a resistance is connected between this pin and VIN outside and the voltage applied to the SW pin is lower than the voltage of the terminal side of the resistance, the upper NchMOSFET is off by operating the current limiter comparator. This operation is reset with respect to each PWM pulse. 3 EN 13 OCP ON/OFF pin. Pin to set the time of the timer (during double the over current detection point) Connect a capacitor between this pin and GND. OCP charge current : 5μA 4 RT 12 MODE Pin to set the oscillation frequency. Connect a resistance between this pin and GND. Pin to switch the over current detection point. Set by the low level (GND) of the ILIM pin. Set by the high level (VIN) of the OCP pin. When this MODE pin is set to the high level and the point of the over current detection is set by using the ILIM pin is exceeded, the value becomes double the original value. Also, when the MODE pin is set to the low level, the point of the over current detection remains an original value. No.A1684-4/6 LV5749NV Timing Chart When the MODE pin is set to the high level and the point of the over current detection is set by using the ILIM pin is exceeded, the value becomes double the original value. Also, when the MODE pin is set to the low level, the point of over current detection remains an original value. Timing chart of the over current detection point switching is as below. t 1.25V OCP 0V over current detection point during High MODE over current detection point during Low MODE Load Current current limit × 2A For example 6A current limit × 1A For example 3A Setting Chart 1. Output voltage setting • Setting of the output voltage VOUT is as follows. R4 R4 VOUT = 1 + R3 × VREF = 1 + R3 × 0.67(typ) [V] 2. Soft Start setting • Setting of capacitor C5 is as follows. Iss × Tss 5μ × Tss C5 = V = 0.67 [F] REF Iss : Charge current value. Tss : Soft Start time 3. OCP Timer setting • Setting of OCP timer capacitor C11 is as follows. 5μ × Tocp Iocp × Tocp [F] C11 = Vocp comp1 = 1.3 Iocp : Charge current value. Tocp : OCP time 4. Current limiter setting • Setting of the current limiter set resistance R5 is as follows. R5 = Rdson × IL max Rdson ×Iout = [Ω] Iilim 18.5μ Iilim : ILIM current value. IL : inductance current value Rdson : ON resistance value between Q1 drain-souces. No.A1684-5/6 LV5749NV Sample Application Circuit VIN = 8.5V to 12V C6 1000pF 14 VIN 5 SYNC SYNC H/L 12 MODE 15 ILIM CBOOT 7 Q1 MCH6406 HDRV 8 VOUT = 5V ON/OFF 3 EN SS 16 SS SW 6 LDRV 9 2 COMP C4 OPEN 4 RT FB 1 D1 DSE010 Q1 MCH6406 C12 OPEN C10 OPEN 10 V GND OCP DD 11 13 C11 680pF ON Semiconductor and the ON logo 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. 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