LM2574, NCV2574 0.5 A, Adjustable Output Voltage, Step-Down Switching Regulator The LM2574 series of regulators are monolithic integrated circuits ideally suited for easy and convenient design of a stepdown www.onsemi.com switching regulator (buck converter). All circuits of this series are capable of driving a 0.5 A load with excellent line and load regulation. These devices are available in fixed output voltages of 3.3 V, 5.0 V, SO16 WB 12 V, 15 V, and an adjustable output version. DW SUFFIX 16 These regulators were designed to minimize the number of external CASE 751G components to simplify the power supply design. Standard series of 1 inductors optimized for use with the LM2574 are offered by several different inductor manufacturers. PDIP8 Since the LM2574 converter is a switchmode power supply, its N SUFFIX efficiency is significantly higher in comparison with popular CASE 626 8 threeterminal linear regulators, especially with higher input voltages. 1 In most cases, the power dissipated by the LM2574 regulator is so low, that the copper traces on the printed circuit board are normally the only heatsink needed and no additional heatsinking is required. PIN CONNECTIONS The LM2574 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 0C to +125C). External 1 16 * * shutdown is included, featuring 60 A (typical) standby current. The 2 15 * * output switch includes cyclebycycle current limiting, as well as FB 3 14 Output thermal shutdown for full protection under fault conditions. 4 13 Sig Gnd * 5 12 ON/OFF V in Features 6 11 Pwr Gnd * 3.3 V, 5.0 V, 12 V, 15 V, and Adjustable Output Versions 7 10 * * Adjustable Version Output Voltage Range, 1.23 to 37 V 4% max 8 9 * * over Line and Load Conditions (Top View) Guaranteed 0.5 A Output Current Wide Input Voltage Range: 4.75 to 40 V 1 8 * FB Requires Only 4 External Components 7 Sig Gnd 2 Output 52 kHz Fixed Frequency Internal Oscillator 3 6 ON/OFF * TTL Shutdown Capability, Low Power Standby Mode 4 5 V Pwr Gnd in High Efficiency (Top View) Uses Readily Available Standard Inductors * No internal connection, but should be soldered to Thermal Shutdown and Current Limit Protection * PC board for best heat transfer. NCV Prefix for Automotive and Other Applications Requiring Site and Control Changes ORDERING INFORMATION PbFree Packages are Available* See detailed ordering and shipping information in the package Applications dimensions section on page 24 of this data sheet. Simple and HighEfficiency StepDown (Buck) Regulators Efficient Preregulator for Linear Regulators DEVICE MARKING INFORMATION See general marking information in the device marking OnCard Switching Regulators section on page 24 of this data sheet. Positive to Negative Converters (BuckBoost) Negative StepUp Converters Power Supply for Battery Chargers *For additional information on our PbFree strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. Semiconductor Components Industries, LLC, 2015 1 Publication Order Number: January, 2015 Rev. 9 LM2574/DLM2574, NCV2574 Typical Application (Fixed Output Voltage Versions) Feedback (3) 1 L1 7.0 - 40 V +V in LM2574 Unregulated 330 H Output 5 DC Input 5.0 V Regulated C (14) in (12) Output 0.5 A Load D1 7 22 F C out 2 Sig4OPwr 3N/OFF 1N5819 220 F Gnd Gnd (4) (6) (5) Representative Block Diagram and Typical Application +V in ON/OFF Unregulated 3.1 V Internal Output R2 ON/OFF DC Input Regulator Voltage Versions ( ) 5 (12) 3 C 3.3 V 1.7 k in (5) 5.0 V 3.1 k 1 (3) 12 V 8.84 k 15 V 11.3 k Feedback Current For adjustable version Limit R2 Fixed Gain R1 = open, R2 = 0 Error Amplifier Comparator Driver R1 Latch Freq 1.0 k L1 V out Shift Output 18 kHz 1.0 Amp 7 (14) Sig Gnd 1.235 V Switch Pwr Gnd C D1 out Band-Gap 52 kHz Thermal 2 4 Reset Reference Load Shutdown Oscillator (4) (6) NOTE: Pin numbers in ( ) are for the SO16W package. Figure 1. Block Diagram and Typical Application ABSOLUTE MAXIMUM RATINGS (Absolute Maximum Ratings indicate limits beyond which damage to the device may occur). Rating Symbol Value Unit Maximum Supply Voltage V 45 V in ON/OFF Pin Input Voltage 0.3 V V +V V in Output Voltage to Ground (Steady State) 1.0 V DW Suffix, Plastic Package Case 751G Max Power Dissipation P Internally Limited W D Thermal Resistance, JunctiontoAir R 145 C/W JA N Suffix, Plastic Package Case 626 Max Power Dissipation P Internally Limited W D Thermal Resistance, JunctiontoAmbient R 100 C/W JA Thermal Resistance, JunctiontoCase R 5.0 C/W JC Storage Temperature Range T 65C to +150C C stg Minimum ESD Rating 2.0 kV (Human Body Model: C = 100 pF, R = 1.5 k ) Lead Temperature (Soldering, 10 seconds) 260 C Maximum Junction Temperature T 150 C J Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality should not be assumed, damage may occur and reliability may be affected. NOTE: ESD data available upon request. www.onsemi.com 2