LM2575 1.0A Step - Down Voltage Switching Regulators Description Features LM2575 of regulators provides all the active functions for a step- down (buck) switching regulator, and drives 1A load with excellent line and load regulation. LM2575 is available in fixed output volt ages of 3.3V, 5V, 12V, 15V and a versatile Adjustable output version. These regulators are simple to use and require a minimum number of external components. 3.3V, 5V, 12V, 15V and Adjustable output versions Adjustable version output voltage range 1.23V to 37V ±4% max over line and load conditions 1A output current Features include internal frequency compensation and a fixed- frequency oscillator. LM2575 high-efficiency replacement for popular three-terminal linear regulators, Requires Only 4 External Components High Efficiency and is requiring a smaller heat sink or even no heat sink. TTL shutdown capability and low power LM2575 performs well with standard inductors from several manufacturers, and simplifying the design of switch-mode power supplies. LM2575 guarantee +/-4% standby mode tolerance on output voltage within specified input voltages and output load conditions, and ±10% on the oscillator frequency. External shutdown is included with 50 uA(typical) standby current. The output switch has cycle-by-cycle Thermal shutdown, current limit protection Uses standard inductors 52 kHz fixed frequency internal oscillator current limiting as well as thermal shutdown for full protection under fault conditions. Application Pre-regulator for linear regulators On-card/ board switching regulators High-efficiency step-down buck regulator Positive to negative converter (buck-boost) TYPICAL APPLICATION 7V - 40V Unregulated DC Input +VIN 1 CIN + 100 µF Feedback 4 LM2575 -5.0 3 GND ON / OFF 5 Output 2 L1 330 µH COUT 330 µF GM 431 D1 1N5819 + 5.0V, 1A Regulated Output LM2575 1.0A Step - Down Voltage Switching Regulators MARKING INFORMATION & PIN CONFIGURATIONS TO-220- 5 VIN Output Ground TO-220- 5B VIN Output ON/OFF Feedback Ground 2 TO-252-5 (DPAK) ON/OFF Feedback VIN Output Ground V V, VVV A Y WW 1 2 3 4 5 TO-263-5(D PAK) ON/OFF Feedback VIN Output Ground = Output Voltage (33=3.3V , 120=12V,A=Adj) = Assembly Location = Year = Weekly ORDERING INFORMATION Ordering Number Output Voltage Package LM2575-ATB5T Adj TO-220-5 50 Units / Tube LM2575 -ATB5BT Adj TO-220-5B 50 Units / Tube LM2575-ATA5R Adj TO-263-5 800 Units/ Tape & Reel LM2575 -ATA5T Adj TO-263-5 50 Units / Tube LM2575 -3.3TB5T 3.3 TO-220-5 50 Units / Tube LM2575 -3.3TB5BT 3.3 TO-220-5B 50 Units / Tube LM2575 -3.3TA5R 3.3 TO-263-5 800 Units/ Tape & Reel LM2575 -3.3TA5T 3.3 TO-263-5 50 Units / Tube LM2575 -5.0TB5T 5.0 TO-220-5 50 Units / Tube LM2575 -5.0TB5BT 5.0 TO-220-5B 50 Units / Tube LM2575-5.0TA5R 5.0 TO-263-5 800 Units/ Tape & Reel LM2575-5.0TA5T 5.0 TO-263-5 50 Units / Tube LM2575 -5.0TC5T 5.0 TO-252-5 80 Units/ Tube LM2575 -5.0TC5R 5.0 TO-252-5 2,500 Units/ Tape & Reel LM2575 -12TB5T 12 TO-220-5 50 Units / Tube LM2575 -12TB5BT 12 TO-220-5B 50 Units / Tube LM2575 -12TA5R 12 TO-263-5 800 Units/ Tape & Reel LM2575 -12TA5T 12 TO-263-5 50 Units / Tube LM2575 -15TB5T 15 TO-220-5 50 Units / Tube LM2575 -15TB5BT 15 TO-220-5B 50 Units / Tube LM2575 -15TA5R 15 TO-263-5 800 Units/ Tape & Reel LM2575 -15TA5T 15 TO-263-5 50 Units / Tube * TB5B: Bent and Staggered Leads of TO-220 package ** For detail Ordering Number identification, please see last page. Shipping ON/OFF Feedback LM2575 1.0A Step - Down Voltage Switching Regulators ABSOLUTE MAXIMUM RATINGS PARAMETER VALUE UNIT 45 V Maximum Supply Voltage -0.3 ON/OFF Pin Input Voltage Output Voltage to Ground (Steady State) V VIN V -1.0 V Internally Limited - -65 to + 150 °C Maximum Junction Temperature +150 °C Lead Temperature (Soldering, 10 sec.) +260 °C VALUE UNIT Power Dissipation Storage Temperature Range RECOMMENDED OPERATING CONDITIONS PARAMETER -40 Temperature Range TJ 125 °C 40 Supply Voltage V BLOCK DIAGRAM Unregulated DC Input + CIN V IN Internal Regulator 1 5 ON/OFF ON/OFF 4 Feedback R2 Fixed Gain Error AMP Comparator + 1.0K R1 - 1 AMP Switch + Driver - Output VOUT L1 2 1.23V Band-Gap Reference D1 52kHz Oscillator Reset Thermal Shutdown Current Limit 3 GND VOUT 3.3V, R2 = 1.7K 5V, R2 = 3.1K 12V, R2 = 8.84K 15V, R2 = 11.3K For ADJ. Version R1 = Open, R2 = 0W + C out L O A D LM2575 1.0A Step - Down Voltage Switching Regulators ELECTRICAL CHARACTERISTICS: LM2575-3.3 (Specifications with standard type face are for TJ = 25°C, and those with boldface type apply over full Operating Temperature Range) Conditions Symbol Output Voltage VIN = 12V, ILOAD = 0.2A VOUT Output Voltage 4.75V VIN 40V, 0.2A ILOAD 1A Parameter Efficiency VIN = 12V, ILOAD = 1A Typ Max Unit 3.234 3.3 3.366 V VOUT 3.168/3.135 3.3 3.432/3.465 V h - 75 - % Min ELECTRICAL CHARACTERISTICS: LM2575-5.0 (Specifications with standard type face are for TJ = 25°C, and those with boldface type apply over full Operating Temperature Range) Conditions Symbol Output Voltage VIN = 12V, ILOAD = 0.2A VOUT Output Voltage 8V VIN 40V, 0.2A ILOAD 1A VIN = 12V, ILOAD = 1A Parameter Efficiency Typ Max Unit 4.900 5.0 5.100 V VOUT 4.800/4.750 5.0 5.200/5.250 V h - 77 - % Min ELECTRICAL CHARACTERISTICS: LM2575-12 (Specifications with standard type face are for TJ = 25°C, and those with boldface type apply over full Operating Temperature Range) Parameter Output Voltage Output Voltage Efficiency Conditions Symbol VIN = 25V, ILOAD = 0.2A 15V VIN 40V, 0.2A ILOAD 1A VIN = 15V, ILOAD = 1A Min Typ Max Unit VOUT 11.76 12.0 12.24 V VOUT 11.52/11.40 12.0 12.48/12.60 V h - 88 - % ELECTRICAL CHARACTERISTICS: LM2575-15 (Specifications with standard type face are for TJ = 25°C, and those with boldface type apply over full Operating Temperature Range) Parameter Feedback Voltage Feedback Voltage Efficiency Conditions Symbol VIN = 30V, ILOAD = 0.2A Min Typ Max Unit VOUT 14.70 15.0 15.30 V 18V VIN 40V, 0.2A ILOAD 1A VOUT 14.40/14.25 15.0 15.60/15.75 V VIN = 18V, ILOAD = 1A h - 88 - % ELECTRICAL CHARACTERISTICS: LM2575-adj (Specifications with standard type face are for TJ = 25°C, and those with boldface type apply over full Operating Temperature Range) Parameter Feedback Voltage Feedback Voltage Efficiency 4 Conditions Symbol VIN = 12V, ILOAD = 0.2A, VOUT = 5V 8V VIN 40V, 0.2A ILOAD 1A VOUT = 5V VIN = 12V, ILOAD = 1.0A, VOUT=5V Min Typ Max Unit VOUT 1.217 1.230 1.243 V VOUT 1.193/1.180 1.230 1.267/1.280 V h - 77 - % LM2575 1.0A Step - Down Voltage Switching Regulators ELECTRICAL CHARACTERISTICS: All Output Voltage Versions (Specifications with standard type face are for TJ = 25°C, and those with boldface type apply over full Operating Temperature Range. Unless otherwise specified, VIN= 12V for the 3.3V, 5.0V and ADJ version, VIN= 25V for 12V version. and VIN= 30V for 15V version. ILOAD = 500 mA) Parameter Feedback Bias Current Oscillator Frequency Saturation Voltage Max Duty Cycle (ON) Current Limit Output Leakage Current Quiescent Current Standby Quiescent Current Conditions Symbol Min Typ Max Unit VOUT = 5V (Adjustable Version Only) IFB - 50 100 / 500 nA (Note 11) FO 47 / 42 52 58 / 63 kHz IOUT = 1A (Notes 4) VSAT - 0.9 1.2 / 1.4 V (Note 5) TDC 93 98 - % (Note 4, 11) ICL 1.7 / 1.3 2.2 3.0 / 3.2 A IOL - 7.5 2 30 mA (Note 6) IQ - 5 10 mA ON/OFF Pin = 5V (OFF) ISTBY - 50 200 mA qJA qJA qJC qJC qJA - 65 45 2 6 37 - °C/W VOUT=0V VIH 2.2 / 2.4 1.4 - V VOUT = Nominal Output Voltage VIL - 1.2 1.0 / 0.8 V ON/OFF Pin = 5V (OFF) VIH - 12 30 mA ON/OFF Pin = 0V (ON) IIL - 0 10 mA (Notes 6, 7) Output = 0 V Output = -1V TO-220 Package, Junction to Ambient (Note 8) TO-220 Package, Junction to Ambient (Note 8) Thermal Resistance TO-220,TO-263, Package, Junction to Case TO-252 Package, Junction to Case TO-263 Package, Junction to Ambient (Note 10) ON/OFF Pin Logic Input Level ON/OFF Pin Input Current Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indic ate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. Guaranteed specifications and Test conditions are shown in Electrical Characteristics. Note 2: All limits guaranteed at 25°C (standard type face) and over full operating temperature range (bold type face). All 25°C limits are 100% production tested. All limits over full operating temperature range are guaranteed via correlation using standard Statistics Quality Control methods. Note 3: External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the LM2575 is used as show in the Figure 2 test circuit, system performance will be as shown in system parameters section of Electrical Characteristics. Note 4: Output pin sourcing current. No diode, inductor or capacitor connected to output. Note 5: Feedback pin removed from output and connected to 0V. Note 6: Feedback pin removed from output and connected to +12V for the Adjustable, 3.3V, and 5V versions, and +25V for the 12V and 15V versions, to force the output transistor OFF. Note 7: VIN = 40V Note 8: Junction to ambient thermal resistance (no external heat sink) for the 5 lead TO-220 package mounted vertically, with ½ inch leads in a socket, or on a PC board with minimum copper area. Note 9: Junction to ambient thermal resistance (no external heat sink) for the 5 lead TO-220 package mounted vertically, with ¼ inch leads soldered to a PC board containing approximately 4 square inches of copper area surrounding the leads. Note 10: If the TO-263 package is used, the thermal resistance can be reduced by increasing the PC board Copper area thermally connected to the package. Using 0.5 square inches of copper area, qJA is 50°C//W, with 1 square inch of copper area, qJA is 37°C/W, and with 1.6 or more square inches of copper area, qJA is 32°C/W. Note 11: The oscillator frequency reduces to approximately 11 kHz in the event of an output short or an Overload which causes the regulated output voltage to drop approximately 40% from the nominal output voltage. This selfprotection feature lowers the Average power dissipation of LM2575 By lowering the minimum duty cycle from 5% down to approximately 2%. 5 LM2575 1.0A Step - Down Voltage Switching Regulators TEST CIRCUIT AND LAYOUT GUIDELINES Careful layout is important with any switching regulator. Rapidly switching currents associated with wiring inductance generate voltage transients, which can cause problems. To minimize inductance and ground loops, the lengths of the leads indicated by heavy lines in Figure 1 below should be kept as short as possible. Singlepoint grounding (as indicated in Figure 1) or ground plane construction should be used for best results. When using the Adjustable version, place the programming resistors as close as possible to LM2575, to keep the sensitive feedback wiring short. Figure 1(a). Fixed Output Voltage Versions LM2575 +VIN 1 FIXED OUTPUT Feedback 4 L1 Output 2 GND 3 VIN Unregulated DC Input VOUT 330 µH ON/OFF 5 + + D1 MBR360 CIN 100 µF COUT 330 µF CIN - 100 µF, 75V, Aluminum Electrolytic COUT - 330 µF, 25V, Aluminum Electrolytic D1 - Schottky, MBR360 L1 - 330 µH, 3L Electronic Corp. TC-331M-1.0A- 5026 R1 - 2k, 0.1% R2 - 6.12k, 0.1% 6 L O A D LM2575 1.0A Step - Down Voltage Switching Regulators Figure 1(b).Adjustable Output Voltage Versions Feedback 4 +VIN LM2575-adj 1 L1 Output 2 GND 3 7V - 40V Unregulated DC Input VOUT=5.0V 330 µH ON/ OFF 5 + CIN 100 µF VOUT = VREF ( 1 + R2 + D1 MBR360 COUT 330 µF R1 L O A D R2 ) R1 VOUT R2 = R1 ( V -1) REF where VREF = 1.23V, R1 between 1k and 5k. Typical Performance Characteristics Figure 2. Switch Saturation Voltage Figure 3. Dropout Voltage 2.0 INPUT-OUTPUT DIFFERENTIAL (V) SATURATION VOLTAGE (V) 1.2 TJ = - 55°C 1.0 TJ = - 25°C 0.8 TJ = 150°C 0.6 0.4 0 0.2 0.4 0.6 0.8 SWITCH CURRENT (A) 1.0 DVOUT = 5% RIND = 0.2W 1.5 ILOAD = 1A 1.0 ILOAD = 200mA 0.5 0 -75 -50 -25 0 25 50 75 100 125 150 JUNCTION TEMPERATURE (°C) LM2575 1.0A Step - Down Voltage Switching Regulators Typical Performance Characteristics Figure 5. Maximum Power Dissipation(TO-263) Figure 4. Quiescent Current 20 QUIESCENT CURRENT (mA) 18 16 POWER DISSIPATION (W) VOUT = 5V Measured at Ground Pin TJ = 25°C 14 12 ILOAD = 1A 10 8 6 4 4 qJA = 32°C/ W qJA = 37°C/ W 3 2 1 qJA = 50°C/ W ILOAD = 200mA qJA = 73°C/ W 0 0 10 20 30 40 50 60 0 INPUT VOLTAGE (V) Figure 7. ON / OFF Pin Current (Sinking) Figure 6. Minimum Operating Voltage 5.0 10 20 30 40 50 60 70 80 90 100 AMBIENT TEMPERATURE (°C) 8 Adjustable Version Only 4.5 7 -40°C 6 3.5 CURRENT(µA) INPUT VOLTAGE (V) 4.0 3.0 2.5 2.0 1.5 1.0 0.5 5 4 3 2 VOUT = 1.23V ILOAD = 120 mA 0 -50 8 VIN = 40V TJ 125°C -25 0 25 50 75 100 125 JUNCTION TEMPERATURE (°C) 1 0 0 5 10 15 20 ON / OFF PIN VOLTAGE (V) 25 LM2575 1.0A Step - Down Voltage Switching Regulators TO-220-5 PACKAGE OUTLINE DIMENSIONS 9.97 ± 0.20 4.50 ± 0.20 9.90 ± 0.20 3.60 ± 0.20 8.0 ± 0.20 8.70 2.80 ± 0.10 7.0 +0.1 1.30 -0.05 4.60 15.90 ± 0.20 3.70 ± 0.20 8.40 1.2 3° 7.0 ± 0.20 9.20 ± 0.20 28.78 MAX 1.50 DP0.20 9.20 ± 0.20 1.30 ± 0.10 1.70 3° 3° 13.08 ± 0.20 3-R0.2 5-0.8 ± 0.10 +0.1 0.50 -0.05 2.40 ± 0.20 1.7(TYP) 3° 3° 2 - R 0.3 Unit: mm 10.00 ± 0.20 TO-263-5 PACKAGE OUTLINE DIMENSIONS 9.90 4.50 1.30 15° 0.40 1.20 3° 4.60 1.50 DP0.20 9.20 Pad Layout 0.10 15.3 3° 2.00 1.20 4.90 17.5 9 2.40 R0.30 0.75 R0.30 1.7 2.54 0.80 0.40 11.5 0.50 1.70 TYP (1.70 ± 0.20) 3.8 10.0 8.0 7.0 4.40 1.07 1.75 3° 3° R 0.3 0.90 R 0.45 7.2 Units: mm 9.20 15.30 10.00 4.90 Unit: mm 9 LM2575 1.0A Step - Down Voltage Switching Regulators TO-220-5B PACKAGE OUTLINE DIMENSIONS 0.18 ± 0.004 4.57 ± 0.1 0.4 ± 0.006 10.16 ± 0.15 0.108 ± 0.006 2.74 ± 0.15 0.05 ± 0.004 1.27 ± 0.1 0.151 ± 0.002 3.84 ± 0.05 0.05 ± 0.004 1.27 ± 0.1 0.4985 ± 0.0075 12.66 ± 0.2 0.032 ± 0.004 0.81 ± 0.1 0.358 ± 0.008 9.1± 0.2 0.9645 ± 0.0075 24.5 ± 0.2 0.996 ± 0.008 25.3± 0.2 0.138 ± 0.004 3.5 ± 0.1 0.105 ± 0.006 2.76± 0.15 0.1535 ± 0.0035 3.9 ± 0.1 0.213 ± 0.004 5.4 ± 0.1 0.173 ± 0.006 4.4 ± 0.15 0.220 TYP 1.700 TYP 0.331 ± 0.006 8.4 ± 0.15 0.268 ± 0.004 0.68 ± 0.1 0.0165 ± 0.0045 0.42 ± 0.11 ( Inches ) mm TO-252-5 PACKAGE OUTLINE DIMENSIONS 0.256 ± 0.004 6.5 ± 0.1 0.024 Ref 0.600 Ref 0.212 ± 0.003 5.375 ± 0.075 Pad Layout 0.02 ± 0.001 0.51 ± 0.02 29° ± 0.5° 7 0.24 ± 0.004 6.10 ± 0.1 3 0.039 ± 0.002 1.0 ± 0.05 0.2835 ± 0.0035 7.20 ± 0.1 0.39 ± 0.008 9.9 ± 0.2 0.9 7 1.27 0.025 ± 0.002 0.64 ± 0.05 0.0235 ± 0.0015 0.60 ± 0.025 0.06 ± 0.004 1.525 ± 0.1 0.003 ± 0.002 0.07 ± 0.05 0.050BSC 1.270BSC 0.091 ± 0.002 2.3 ± 0.05 ( 10 6.25 Units: mm Inches ) mm