LM2576 Series Description The MIK2576 series of regulators are monolithic integrated circuits that provide all the active functions for a step-down (buck) switching regulator, capable of driving 3A load with excellent line and load regulation. These devices are available in fixed output voltages of 3.3V, 5V, 12V, 15V, and an adjustable output versions. Requiring a minimum number of external components, these regulators are simple to use and include internal frequency compensation and a fixed-frequency oscillator. The MIK2576 series offers a high-efficiency replacement for popular three-terminal linear regulators. It substantially reduces the size of the heat sink, and in some cases no heat sink is required. A standard series of inductors optimized for use with the MIK2576 are available from several different manufacturers. This feature greatly simplifies the design of switch-mode power supplies. Other features include a guaranteed 4% tolerance on output voltage within specified input voltages and output load conditions, and 10% on the oscillator frequency. External shutdown is included, featuring 50A (typical) standby current. The output switch includes cycle-by-cycle current limiting, as well as thermal shutdown for full protection under fault conditions. Note: The MIK2576HV is not produced yet. Applications Features * * * * * * * * * * * * * * * 3.3V, 5V, 12V, 15V, and adjustable output versions Adjustable version output voltage range 1.23V to 37V (57V for HV version) 4% max over line and load conditions Guaranteed 3A output current Wide input voltage range, 40V up to 60V for HV version Requires only 4 external components 52 kHz fixed frequency oscillator TTL shutdown capability, low power standby mode High efficiency Uses readily available standard inductors Thermal shutdown and current limit protection Typical application 7V - 40V (60V for HV) UNREGULATED DC INPUT Figure 1.(Fixed Output Voltage Versions) MIK2576/ FEEDBACK MIK2576HV- 4 L1 OUTPUT 5.0 +VIN 1 2 + GND Simple high-efficiency step-down (buck) regulator Efficient pre-regulator for linear regulators On-card switching regulators Positive to negative converter (Buck-Boost) 3 5 ON/OFF 100 H D1 CIN 1N5822 + COUT 1000 F +5V REGULATED OUTPUT 3A LOAD BEIJING ESTEK ELECTRONICS CO.,LTD 1 LM2576 Series Block Diagram VIN UNREGULATED DC INPUT ON/OFF INTERNAL REGULATOR 1 ON/OFF 5 + 4 CIN FEEDBACK R2 R1 1.0k FIXED GAIN ERROR AMP + - COMPARATOR DRIVER 3 AMP SWITCH + - OUTPUT L1 VOUT 2 + 3 1.23V 52kHZ BAND-GAP REFERENCE OSCILLATOR D1 COUT RESET THERMAL SHUTDOWN CURRENT LIMIT L O A D GND 3.3V, R2 =1.7K 5V, R2 = 3.1K 12V, R2 = 8.84K 15V, R2 =11.3K For ADJ, Version R1 = Open, R2 =0 Ordering information Temperature Range -40C TA 125C Output Voltage, V 3.3 5.0 12 Package Type 15 ADJ MIK2576HVS-3.3 MIK2576HVS-5.0 MIK2576HVS-12 MIK2576HVS-15 MIK2576HVS-ADJ MIK2576S-3.3 MIK2576S-5.0 MIK2576S-12 MIK2576S-15 MIK2576HVT-3.3 MIK2576HVT-5.0 MIK2576HVT-12 MIK2576HVT-15 MIK2576HVTADJ MIK2576T-3.3 MIK2576T-5.0 MIK2576T-12 MIK2576T-15 TO-263 MIK2576S-ADJ TO-220 MIK2576T-ADJ BEIJING ESTEK ELECTRONICS CO.,LTD 2 LM2576 Series Absolute Maximum Ratings (Note 1) Parameter Maximum Units 45 63 V Maximum Supply Voltage MIK2576 MIK2576HV -0.3V V +VIN -1 Internally Limited -65 to +150 150 2 260 ON/OFF Pin Input Voltage Output Voltage to Ground (Steady State) Power Dissipation Storage Temperature Range Maximum Junction Temperature Minimum ESD Rating (C= 100pF, R = 1.5 k) Lead Temperature (Soldering, 10 Seconds) V W C C kV C Operating Ratings Parameter Temperature Range MIK2576/ MIK2576HV Supply Voltage MIK2576 MIK2576HV Value -40 TJ +125 Units C 40 60 V Electrical Characteristics MIK2576-3.3, MIK2576HV-3.3 Specifications with standard type face are for T J = 25C, and those with boldface type apply over full Operating Temperature Range. Symbol Parameter Conditions MIK2576-3.3 MIK2576HV-3.3 Typ Units (Limits) Limit (Note 2) SYSTEM PARAMETERS (Note 3) Test Circuit Figure 2 VOUT VOUT VOUT VIN =12V, ILOAD =0.5A Circuit of Figure 2 3.3 Output Voltage MIK2576 6V VIN 40V, 0.5A ILOAD 3A Circuit of Figure 2 3.3 Output Voltage MIK2576HV 6V VIN 60V, 0.5A ILOAD 3A Circuit of Figure 2 3.3 Efficiency VIN =12V, ILOAD =3A 75 Output Voltage 3.234 3.366 V V(Min) V(Max) 3.168/3.135 3.432/3.465 V V(Min) V(Max) 3.168/3.135 3.450/3.482 V V(Min) V(Max) % Electrical Characteristics MIK2576-5.0, MIK2576HV-5.0 Specifications with standard type face are for T J = 25C, and those with boldface type apply over full Operating Temperature Range. Symbol Parameter Conditions MIK2576-5.0 MIK2576HV-5.0 Typ Units (Limits) Limit (Note 2) SYSTEM PARAMETERS (Note 3) Test Circuit Figure 2 VOUT VOUT VOUT Output Voltage VIN =12V, ILOAD =0.5A Circuit of Figure 2 5.0 Output Voltage MIK2576 0.5A ILOAD 3A, 8V VIN 40V Circuit of Figure 2 5.0 Output Voltage MIK2576HV 0.5A ILOAD 3A, 8V VIN 60V Circuit of Figure 2 5.0 Efficiency VIN =12V, ILOAD =3A 77 4.900 5.100 V V(Min) V(Max) 4.800/4.750 5.200/5.250 V V(Min) V(Max) 4.800/4.750 5.225/5.275 V V(Min) V(Max) % BEIJING ESTEK ELECTRONICS CO.,LTD 3 LM2576 Series Electrical Characteristics MIK2576-12, MIK2576HV-12 Specifications with standard type face are for T J = 25C, and those with boldface type apply over full Operating Temperature Range. Symbol Parameter Conditions MIK2576-12 MIK2576HV-12 Typ Units (Limits) Limit(Note 2) SYSTEM PARAMETERS (Note 3) Test Circuit Figure 2 VOUT VOUT VOUT Output Voltage VIN =25V, ILOAD =0.5A Circuit of Figure 2 12 Output Voltage MIK2576 0.5A ILOAD 3A, 15V VIN 40V Circuit of Figure 2 12 Output Voltage MIK2576HV 0.5A ILOAD 3A, 15V VIN 60V Circuit of Figure 2 12 Efficiency VIN =15V, ILOAD =3A 88 11.76 12.24 V V(Min) V(Max) 11.52/11.40 12.48/12.60 V V(Min) V(Max) 11.52/11.40 12.54/12.66 V V(Min) V(Max) % Electrical Characteristics MIK2576-15, MIK2576HV-15 Specifications with standard type face are for T J = 25C, and those with boldface type apply over full Operating Temperature Range. Symbol Parameter Conditions MIK2576-15 MIK2576HV-15 Typ Units (Limits) Limit (Note 2) SYSTEM PARAMETERS (Note 3) Test Circuit Figure 2 VOUT VOUT VOUT VIN =25, ILOAD =0.5A Circuit of Figure 2 15 Output Voltage MIK2576 0.5A ILOAD 3A, 18 VIN 40V Circuit of Figure 2 15 Output Voltage MIK2576HV 0.5A ILOAD 3A, 18 VIN 60V Circuit of Figure 2 15 Efficiency VIN =18V, ILOAD =3A 88 Output Voltage 14.70 15.30 V V(Min) V(Max) 14.40/14.25 15.60/15.75 V V(Min) V(Max) 14.40/14.25 15.68/15.83 V V(Min) V(Max) % Electrical Characteristics MIK2576-ADJ, MIK2576HV-ADJ Specifications with standard type face are for T J = 25C, and those with boldface type apply over full Operating Temperature Range. Symbol Parameter Conditions MIK2576-ADJ MIK2576HV-ADJ Typ Units (Limits) Limit(Note 2) SYSTEM PARAMETERS (Note 3) Test Circuit Figure 2 VOUT VOUT VOUT Feedback Voltage VIN =12V, ILOAD =0.5A, VOUT =5V Circuit of Figure 2 1.230 Feedback Voltage MIK2576 0.5A ILOAD 3A , 8V VIN 40V VOUT =5V Circuit of Figure 2 1.230 Feedback Voltage MIK2576HV 0.5A ILOAD 3A, 8V VIN 60V, VOUT =5V Circuit of Figure 2 1.230 Efficiency VIN =12V, ILOAD =3A, VOUT =5V 77 1.217 1.243 V V(Min) V(Max) 1.193/1.180 1.267/1.280 V V(Min) V(Max) 1.193/1.180 1.273/1.286 V V(Min) V(Max) % BEIJING ESTEK ELECTRONICS CO.,LTD 4 LM2576 Series All Output Voltage Versions Electrical Characteristics Specifications with standard type face are for T J = 25C, and those with boldface type apply over full Operating Temperature Range. Unless otherwise specified, V IN =12V for the 3.3V, 5V, and Adjustable version, V IN =25V for the 12V version, and V IN =30V for the 15V version, , ILOAD =500mA. Symbol Parameter Conditions MIK2576-XX MIK2576HV-XX Units (Limits) Typ Limit (Note 2) 100/500 nA 47/42 58/63 kHz kHz(Min) kHz(Max) 1.8/2.0 V V(Max) 93 % %(Min) 4.2/3.5 6.9/7.5 A A(Min) A(Max) DEVICE PARAMETERS Ib Feedback Bias Current VOUT =5V (Adjustable Version Only) 50 fO Oscillator Frequency (Note 8) 52 VSAT DC Saturation Voltage Max Duty Cycle (ON) ICL Current Limit IL Output Leakage Current Output = 0V IQ Quiescent Current ISTBY Standby Quiescent Current ___ ON/OFF CONTROL VIH __ ON/OFF Pin VIL Logic Input Level IIH __ ON/OFF Pin Input Current IIL Note Note Note Note Note Note Note Note IOUT =3A (Note 4) 1.4 (Note 5) 98 (Notes 4, 8) 5.8 2 (Notes 6, 7): Output = -1V Output = -1V (Note 6) 30 mA(Max) mA mA(Max) 10 mA mA(Max) 200 A A(Max) 7.5 5 ___ ON/OFF Pin = 5V (OFF) 50 VOUT = 0V 1.4 2.2/2.4 V(Min) VOUT = Nominal Output Voltage 1.2 1.0/0.8 V(Max) __ ON/OFF Pin = 5V (OFF) 12 30 A A(Max) __ ON/OFF Pin = 0V (ON) 0 10 A A(Max) 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. 2: All limits guaranteed at room temperature (standa rd type face) and at temperature extremes (bold type face). 3: External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the MIK2576/MIK2576HV is used as shown in the Figure 2 test circuit, system performance will be as shown in system parameters section of Electrical Characteristics. 4: Output pin sourcing current. No diode, inductor or capacitor connected to output. 5: Feedback pin removed from output and connected to 0V. 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. 7: VIN =40V (60V for high voltage version). 8: 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 self protections feature lowers the average power dissipation of the IC by lowering the minimum duty cycle from 5% down to approximately 2%. BEIJING ESTEK ELECTRONICS CO.,LTD 5 LM2576 Series Typical Performance Characteristics (Circuit of Figure 2) Normalized Output Voltage VIN =20V I L OA D = 500mA Normalized at TJ =25C Line Regulation Dropout Voltage I L OA D = 500mA TJ =25C L1 = 150 H I L OA D = 3A 3.3V, 5V & ADJ 12V & 15V I L OA D = 1A I L OA D = 200mA RIND = 0.1 JUNCTION TEMPERATURE (C) Standby Quiescent Current INPUT VOLTAGE (V) JUNCTION TEMPERATURE (C) Quiescent Current Current Limit VIN = 25V VIN = 40V VOUT = 5V Measured at Ground Pin TJ =25C VON/OFF = 5V VIN =12 V ILOAD = 3A ILOAD = 200mA JUNCTION TEMPERATURE (C) Switch Saturation Voltage INPUT VOLTAGE (V) JUNCTION TEMPERATURE (C) Efficiency Oscilator Frequency Normalized at 25C I L OA D = 3A TJ =25C I L OA D = 200mA 15V OUT -55C 25C 150C VIN = 40V 5V IL OA D = 3A VIN = 12V IL OA D = 200mA SWITCH CURRENT (A) Minimum Operating Voltage Adjustable Version Only INPUT VOLTAGE (V) JUNCTION TEMPERATURE (C) Quiescent Current vs Duty Cycle Feedback Voltage vs Duty Cycle Adjustable Version Only Adjustable Version Only I LOAD = 500mA VIN = 7V VIN = 40V VIN = 40V VOUT 1.23V I LOAD = 500mA JUNCTION TEMPERATURE (C) VIN = 7V I LOAD = 500mA DUTY CYCLE (%) DUTY CYCLE (%) BEIJING ESTEK ELECTRONICS CO.,LTD 6 LM2576 Series Maximum Power Dissipation (TO-263) Feedback Pin Current Adjustable Version Only JA = 32C/W J A = 37C/W J A = 50C/W J A = 73C/W AMBIENT TEMPERATURE (C) JUNCTION TEMPERATURE (C) Switching Waveforms Response Load Transient A Output Voltage Change B Load Current C D 5 s/div 100 s/div VOUT =15V A: Output Pin Voltage, 50V/div B: Output Pin Current, 2A/div C: Inductor Current, 2A/div D: Output Ripple Voltage, 50mV/div, AC-Coupled Horizontal Time Base: 5s/div BEIJING ESTEK ELECTRONICS CO.,LTD 7 LM2576 Series Test Circuit and Layout Guidelines As in any switching regulator, layout is very important. Rapidly switching currents associated with wiring inductance generate voltage transients which can cause problems. For minimal inductance and ground loops, the length of the leads indicated by heavy lines should be kept as short as possible. Single-point grounding (as indicated) or ground plane construction should be used for best results. When using the Adjustable version, physically locate the programming resistors near the regulator, to keep the sensitive feedback wiring short. Fixed Output Voltage Versions (Figure 2a) FEEDBACK +VIN 1 MIK2576HVFIXED OUTPUT 4 2 + VIN UNREGULATED DC INPUT 1 00 GN F D 3 ON/OFF L1 VOUT OUTPUT 5 100 H + D1 MBR360 L O A D COUT 1000 F CIN -- 100F, 75V, Aluminum Electrolytic COUT -- 1000F, 25V, Aluminum Electrolytic D1 -- Schottky, MBR360 L1 -- 100H, Pulse Eng. PE-92108 R1 -- 2k, 0.1% R2 -- 6.12k, 0.1% Adjustable Output Voltage Version +VIN 1 MIK2576HVADJ FEEDBACK 4 L1 OUTPUT 2 7V -60V UNREGULATED DC INPUT VOUT = R2 + 100 CIN F GND 3 ON/OFF (Figure 2b) 5 VOUT 5.00V 100 H MBR360 COUT + 1000 F R2 L O A D R1 R VREF 1 ( +2 ) R V R 1 (V OUT- )1 REF where VREF = 1.23V, R1 between 1k and 5k Address : 6A06--6A07 Rm 6A07,Changyin Office Building ,No.88,Yong Ding Road,Hai Dian District ,Beijing Postalcode:100039 Tel: 86-010-58895780 / 81 / 82 / 83 / 84 Fax : 010-58895793 Http://www.estek.com.cn Email:sales@estek.com.cn REV No:01-060813 BEIJING ESTEK ELECTRONICS CO.,LTD 8