LM2576T-ADJ

3A, 52kHz, Step-Down Switching Regulator FEATURES LM2576 SOP8-PP PKG z 3.3V, 5.0V, 12V and Adjustable Output Versions z Adjustable Version Output Voltage Range, 1.23 to 37V +/- 4% AG10Maximum Over Line and Load Conditions z Guaranteed 3.0A Output Current z Wide Input Voltage Range z Requires Only 4 External Components z 52kHz Fixed Frequency Internal Oscillator z TTL Shutdown Capability, Low Power Standby Mode z High Efficiency z Uses Readily Available Standard Inductors z Thermal Shutdown and Current Limit Protection z Moisture Sensitivity Level 3 for SMD packages TO-220 PKG TO-263 PKG APPLICATION z z z z z z Simple High-Efficiency Step-Down(Buck) Regulator Efficient Pre-Regulator for Linear Regulators On-Card Switching Regulators Positive to Negative Converter(Buck-Boost) Negative Step-Up Converters Power Supply for Battery Chargers ORDERING INFORMATION Device LM2576DP-X.X LM2576T-X.X LM2576R-X.X Marking LM2576-X.X LM2576-X.X LM2576-X.X Package SOP8-PP TO-220 TO-263 DESCRIPTION The LM2576 series of regulators are monolithic integrated circuits ideally suited for easy and convenient design of a step-down switching regulator (buck converter). All circuits of this series are capable of driving a 3.0A load with excellent line and load regulation. These devices are available in fixed output voltages of 3.3V, 5.0V, 12V and an adjustable output version. These regulators were designed to minimize the number of external components to simplify the power supply design. Standard series of inductors optimized for use with the LM2576 are offered by several different inductor manufacturers. Since the LM2576 converter is a switch-mode power supply, its efficiency is significantly higher in comparison with popular three-terminal linear regulators, especially with higher input voltages. In many cases, the power dissipated is so low that no heatsink is required or its size could be reduced dramatically. A standard series of inductors optimized for use with the LM2576 are available from several different manufacturers. This feature greatly simplifies the design of switch-mode power supplies. The LM2576 features include a guaranteed +/- 4% tolerance on output voltage within specified input voltages and output load conditions, and +/-10% on the oscillator frequency (+/- 2% over 0˚C to 125˚C). External shutdown is included, featuring 80㎂(typical) standby current. The output switch includes cyclebycycle current limiting, as well as thermal shutdown for full protection under fault conditions. Dec 2011 – Rev. 1.3 -1 - HTC 3A, 52kHz, Step-Down Switching Regulator LM2576 Ordering Information VOUT ADJ 3.3V 5.0V 12V Package Order No. Description Package Marking Status SOP8-PP LM2576DP-ADJ 3A, Adjustable, 52kHz, On/off LM2576-ADJ Contact Us TO220-5L LM2576T-ADJ 3A, Adjustable, 52kHz, On/off LM2576-ADJ Active TO263-5L LM2576R-ADJ 3A, Adjustable, 52kHz, On/off LM2576-ADJ Active SOP8-PP LM2576DP-3.3 3A, Fixed, 52kHz, On/off LM2576-3.3 Contact Us TO220-5L LM2576T-3.3 3A, Fixed, 52kHz, On/off LM2576-3.3 Active TO263-5L LM2576R-3.3 3A, Fixed, 52kHz, On/off LM2576-3.3 Active SOP8-PP LM2576DP-5.0 3A, Fixed, 52kHz, On/off LM2576-5.0 Contact Us TO220-5L LM2576T-5.0 3A, Fixed, 52kHz, On/off LM2576-5.0 Active TO263-5L LM2576R-5.0 3A, Fixed, 52kHz, On/off LM2576-5.0 Active SOP8-PP LM2576DP-12 3A, Fixed, 52kHz, On/off LM2576-12 Contact Us TO220-5L LM2576T-12 3A, Fixed, 52kHz, On/off LM2576-12 Active TO263-5L LM2576R-12 3A, Fixed, 52kHz, On/off LM2576-12 Active LM 2576 Output Voltage : ADJ / 3.3V / 5.0V /12V Package Type DP : SOP8-PP T : TO220-5L R : TO263-5L Root Name Product Code Dec 2011 – Rev. 1.3 -2 - HTC 3A, 52kHz, Step-Down Switching Regulator LM2576 PIN CONFIGURATION VIN 1 8 N.C VOUT 2 FEEDBACK 3 ON/OFF Exposed 7 N.C PAD 6 GND 4 5 N.C. SOP8-PP TO220-5L TO263-5L PIN DESCRIPTION Package TO-220 5L TO-263 5L SOP8-PP Symbol 1 1 VIN 2 2 VOUT 3 6 GND 4 3 FEEDBACK 5 4 ON/OFF - 5, 7, 8 N.C. Description This pin is the positive input supply for the LM2576 step–down switching regulator. In order to minimize voltage transients and to supply the switching currents needed by the regulator, a suitable input bypass capacitor must be present. (Cin in Figure 1). This is the emitter of the internal switch. The saturation voltage VSAT of this output switch is typically 1.5V. It should be kept in mind that the PCB area connected to this pin should be kept to a minimum in order to minimize coupling to sensitive circuitry. Circuit ground pin. See the information about the printed circuit board layout. This pin senses regulated output voltage to complete the feedback loop. The signal is divided by the internal resistor divider network R2, R1 and applied to the non–inverting input of the internal error amplifier. In the adjustable version of the LM2576 switching regulator this pin is the direct input of the error amplifier and the resistor network R2, R1 is connected externally to allow programming of the output voltage. It allows the switching regulator circuit to be shutdown using logic level signals, thus dropping the total input supply current to approximately 80uA. The threshold voltage is typically 1.4V. Applying a voltage above this value (up to +Vin) shuts the regulator off. If the voltage applied to this pin is lower than 1.4V or if this pin is left open, the regulator will be in the "on" condition No Connect. * Exposed Pad of SOP8-PP package should be externally connected to GND. Dec 2011 – Rev. 1.3 -3 - HTC 3A, 52kHz, Step-Down Switching Regulator LM2576 Typical Application (Fixed Output Voltage Versions) Figure 1. Block Diagram and Typical Application Dec 2011 – Rev. 1.3 -4 - HTC 3A, 52kHz, Step-Down Switching Regulator LM2576 ABSOLUTE MAXIMUM RATINGS (Absolute Maximum Ratings indicate limits beyond which damage to the device may occur) Rating Symbol Value UNIT Maximum Supply Voltage Vin 45 V On/Off Pin Input Voltage - -0.3V ≤ V ≤ +Vin V Output Voltage to Ground (Steady-State) Power Dissipation SOP8-PP 8Lead Thermal Resistance, Junction to Ambient Thermal Resistance, Junction to Case TO-220 5Lead Thermal Resistance, Junction to Ambient Thermal Resistance, Junction to Case TO-263 5Lead Thermal Resistance, Junction to Ambient Thermal Resistance, Junction to Case Storage Temperature Range Minimum ESD Rating(Human Body Model: C=100 pF, R=1.5kΩ Lead Temperature (Soldering, 10seconds) - -1.0 V PD θJA θJC PD θJA θJC PD θJA θJC TSTG Internally Limited Contact us Contact us Internally Limited 65 5 Internally Limited 70 5 -60 to +150 W ℃/W ℃/W W ℃/W ℃/W W ℃/W ℃/W ℃ - 2.0 kV - 260 ℃ TJ 150 ℃ Maximum Junction Temperature OPERATING RATINGS (Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications, see the Electrical Characteristics.) Rating Symbol Value. Unit Operating Junction Temperature Range TJ -40 to +125 ℃ Supply Voltage Vin 40 V Dec 2011 – Rev. 1.3 -5 - HTC 3A, 52kHz, Step-Down Switching Regulator LM2576 ELECTRICAL CHARACTERISTICS / SYSTEM PARAMETERS ([Note 1] Test Circuit Figure 15) (Unless otherwise specified, Vin = 12V for the 3.3V, 5.0V, and Adjustable version, Vin = 25V for the 12V version. ILoad = 500 mA. For typical values TJ = 25°C, for min/max values TJ is the operating junction temperature range that applies [Note 2], unless otherwise noted.) Characteristics LM2576-3.3V ([Note 1] Test Circuit Figure 2) Output Voltage (Vin = 12V, ILOAD=0.5A, TJ=25℃) Output Voltage (6.0V≤Vin≤40V, 0.5A≤ILOAD≤3.0A TJ=25℃ TJ= -40℃ ~ +125℃ Efficiency (Vin=12V, ILOAD=3.0A) LM2576-5.0V ([Note 1] Test Circuit Figure 2) Output Voltage (Vin = 12V, ILOAD=0.5A, TJ=25℃) Output Voltage (8.0V≤Vin≤40V, 0.5A≤ILOAD≤3.0A TJ=25℃ TJ= -40℃ ~ +125℃ Efficiency (Vin=12V, ILOAD=3.0A) LM2576-12V ([Note 1] Test Circuit Figure 2) Output Voltage (Vin = 25V, ILOAD=0.5A, TJ=25℃) Output Voltage (15V≤Vin≤40V, 0.5A≤ILOAD≤3.0A TJ=25℃ TJ= -40℃ ~ +125℃ Efficiency (Vin=25V, ILOAD=3.0A) LM2576-ADJ ([Note 1] Test Circuit Figure 2) Feedback Voltage (Vin=12V, ILOAD=0.5A, TJ=25℃) Symbol Min TYP Max Unit Vout 3.234 3.3 3.366 V Vout 3.3 75 3.432 3.465 - V η 3.168 3.135 - % Vout 4.9 5.0 5.1 V Vout 5.0 77 5.2 5.25 - V η 4.8 4.75 - % Vout 11.76 12 12.24 V Vout 12 88 12.48 12.6 - V η 11.52 11.4 - % Vout 1.217 1.23 1.243 V Vout 1.193 1.18 - 1.23 77 1.267 1.28 - V Feedback Voltage (8.0V≤Vin≤40V, 0.5A≤ILOAD≤3.0A, Vout=5.0V) TJ=25℃ TJ= -40℃ ~ +125℃ Efficiency (Vin=12V, ILOAD=3.0A, Vout=5.0V) η % 1. External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the LM2576 is used as shown in the Figure 15 test circuit, system performance will be as shown in system parameters section. 2. Tested junction temperature range for the LM2576: Tlow = –40°C Thigh = +125°C Dec 2011 – Rev. 1.3 -6 - HTC 3A, 52kHz, Step-Down Switching Regulator LM2576 ELECTRICAL CHARACTERISTICS / Device Parameters (Unless otherwise specified, Vin = 12V for the 3.3V, 5.0V, and Adjustable version, Vin = 25V for the 12V version. ILoad = 500 mA. For typical values TJ = 25°C, for min/max values TJ is the operating junction temperature range that applies [Note 2], unless otherwise noted.) Characteristics Symbol MIN. TYP. MAX. Unit Ib - 25 - 100 200 nA 47 42 52 - 58 63 VSAT - 1.5 - 1.8 2 V DC 94 98 - % ICL 4.2 3.5 5.8 - 6.9 7.5 A IL - 0.8 6 50 30 mA IQ - 5 - 9 11 mA ISTBY - 80 - 200 400 µA 2.2 2.4 1.4 - - VIL - 1.2 - 1 0.8 V IIH IIL - 15 0 30 0.5 µA All Output Voltage Versions Feedback Bias Current (Vout=5.0V [Adjustable Version Only]) TJ=25℃ TJ= -40 to +125℃ Oscillator Frequency [Note 3] TJ=25℃ TJ= 0 to +125℃ TJ= -40 to +125℃ Saturation Voltage (Iout=3.0A [note 4]) TJ= 25℃ TJ= -40 to +125℃ FOSC Max Duty Cycle (“0”) [Note 5] Current Limit (Peak Current [Note 3 and 4]) TJ= 25℃ TJ= -40 to +125℃ Output Leakage Current [Note 6 and 7], TJ=25℃ Output = 0V Output = -1.0V Quiescent Current [Note 6] TJ= 25℃ TJ= -40 to +125℃ Standby Quiescent Current (ON/OFF Pin = 5.0V ("off")) TJ=25℃ TJ= -40 to +125℃ ON/OFF Pin Logic Input Level (Test circuit Figure 15) Vout=0V TJ=25℃ TJ= -40 to +125℃ Vout=Nominal Output Voltage TJ=25℃ TJ= -40 to +125℃ ON/OFF Pin Input Current (Test Circuit Figure 15) ON/OFF Pin = 5.0V (Regulator OFF), TJ=25℃ ON/OFF Pin = 0V (Regulator ON), TJ=25℃ VIH kHz V 3. The oscillator frequency reduces to approximately 18 kHz in the event of an output short or an overload which causes the regulated output voltage to drop approximately 40% from the nominal voltage. This self protection feature lowers the average dissipation of the IC by lowering the minimum duty cycle from 5% down to approximately 2% 4. Output sourcing current. No diode, inductor or capacitor connected to output pin. 5. Feedback removed from output and connected to 0V. 6. Feedback removed from output and connected to +12V for the Adjustable, 3.3V, and 5.0V versions, and +25V for the 12V version, to force the output transistor “off”. 7. Vin = 40V. Dec 2011 – Rev. 1.3 -7 - HTC 3A, 52kHz, Step-Down Switching Regulator LM2576 TYPICAL PERFORMANCE CHARACTERISTICS (Circuit of Figure 15) Figure 2. Normalized Output Voltage Figure 3. Line Regulation Figure 4. Dropout Voltage Figure 5. Current Limit Figure 6. Quiescent Current Dec 2011 – Rev. 1.3 Figure 7. Standby Quiescent Current -8 - HTC 3A, 52kHz, Step-Down Switching Regulator LM2576 TYPICAL PERFORMANCE CHARACTERISTICS (Circuit of Figure 15) Figure 8. Standby Quiescent Current Figure 9. Switch Saturation Voltage Figure 10. Oscillator Frequency Figure 11. Minimum Operating Voltage Figure 12. Feedback Pin Current Dec 2011 – Rev. 1.3 -9 - HTC 3A, 52kHz, Step-Down Switching Regulator LM2576 TYPICAL PERFORMANCE CHARACTERISTICS Figure 13. Switching Waveforms Figure 14. Load Transient Response Vout = 15V A : Output Pin Voltage, 10V/DIV B: Inductor Current, 2.0A/DIV C: Inductor Current, 2.0A/DIV D: Output Ripple Voltage, 50mV/dDIV, AC-Coupled Horizontal Time Base : 5.0 µs/DIV Dec 2011 – Rev. 1.3 - 10 - HTC 3A, 52kHz, Step-Down Switching Regulator LM2576 Cin - 100µF, 75V, Aluminium Electrolytic Cout - 1000µF, 25V, Aluminium Electrolytic D1 - Schottky, MBR360 L1 -100 µH, Pulse Eng. PE-92108 R1 - 2.0 k, 0.1% R2 - 6.12 k, 0.1% Vout = Vref (1.0 + R2 = R1( R2 ) R1 Vout - 1.0) Vref Where Vref = 1.23V, R1 between 1.0k and 5.0k Figure 15. Typical Test Circuit Dec 2011 – Rev. 1.3 - 11 - HTC