S5ULM2576 Simple Switcher Elektronische Bauelemente 3A Step-Down Voltage Regulator Description The S5ULM2576 series of regulators are monolithic integrated circuits that provide all 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 voltage of 3.3V,5V,12V,15V and an adjustable output version. Requiring a min. rumber of external components, these regulators are simple to use and include internal frequency components and a fixed-frequency oscillator. The S5ULM2576 series offers a highefficiency replacement for popular three-terminal linear regulators. If substantially reduces the size of the heat sink, and in some cases no heat sink is required. A standard series if inductors optimized for use with the S5ULM2576 are available from several different manufactures. The feature greatly simplifies the design of switching-mode power supplies. Other feature include a guaranteed ± 4% to tolerance on output voltage within specified input voltages and output load condition, and ±10% on the oscillator frequency. External shutdown is included, featuring 50uA(Typ.) standby current. The output switch includes cycle-bycycle current limiting, as well as thermal shutdown for full protection under fault condition. Features * High Efficiency REF. A b L4 c L1 E Millimeter Min. 4.40 0.66 0.00 0.36 2.29 9.80 REF. Max. 4.80 c2 0.91 L2 0.30 B D 0.5 e 2.79 L 10.4 Millimeter Min. Max. 1.25 1.45 1.27 REF. 8.6 9.0 1.70 REF. 14.6 15.8 0˚ 8˚ * Wide Input Voltage Range * 52KHz Fixed Frequency Oscillator * 3.3V,5V,12V,15V and Adjustable Output Versions * Uses Readily Available Standard Inductors * TTL Shutdown Capability, Low Power Standby Mode * Thermal Shutdown And Current Limit Protection * Guaranteed 3A Output Current * Efficient Per-regulator For Linear Regulators * Requires Only 4 Extermal Components * Adjustable Version Output Voltage Range, 1.23V to 37V ± 4% Max. Over Line And Load Conditions Applications * Positive To Negative Converter (Buck-Boost) * Simple High-Effciency Step-Down (Buck) Regulator * One-Card Switching Regulators http://www.SeCoSGmbH.com/ 01-Jun-2002 Rev. A Any changing of specification will not be informed individual Page 1 of 8 S5ULM2576 Simple Switcher Elektronische Bauelemente 3A Step-Down Voltage Regulator Typical Application (Fixed Output Voltage Version) Description GND Typically a large storage capacitor is connected from this pin to ground to insure that the input 1.3V S5ULM2576-5.0 or open= output enable. tage does not sag below the minimum dropout voltage during the load V higher than Vout in order for the device to NC Block Diagram 3.3V, R2=17k 5.0V, R2=3.1k 12V, R2=8.84k 15V, R2=11.3k For Adjustable version, R1=open, R2=0 Absolute Maximum Ratings (Note1) Maximum Supply Voltage Parameter ON/OFF pin input Voltage Output Voltage to ground (steady state) Power dissipation Storage Temperature Maximum junction temperature Minimum ESD rating (C=100pF, R=1.5k ) Lead temperature (soldering, 10seconds) Operating Ratings Temperature range Supply Voltage http://www.SeCoSGmbH.com/ 01-Jun-2002 Rev. A Parameter Ratings 45 -0.3 V +VIN -1 Internally Limited -65 ~ +150 +150 2k +260 Unit V V V Ratings -40 TJ +125 40 Unit V V Any changing of specification will not be informed individual Page 2 of 8 S5ULM2576 Simple Switcher Elektronische Bauelemente 3A Step-Down Voltage Regulator S5ULM2576-3.3 Electrical Characteristics Specifications with standard type face are for TJ=25 , and those with boldface type apply over full operating temperature range Parameter Symbol Conditions System Parameters (Note3) Test Circuit Figure 2 VIN=12V, ILOAD=0.5A Output Voltage VOUT Circuit of Figure 2 6V VIN 40V, 0.5A ILOAD 3A Output Voltage VOUT Circuit of Figure 2 Efficiency VIN=12V, ILOAD=3A Min Typ Max Unit 3.234 3.3 3.366 V 3.168/3.135 3.3 3.432/3.465 V 75 % S5ULM2576-5.0 Electrical Characteristics Specifications with standard type face are for TJ=25 , and those with boldface type apply over full operating temperature range Parameter Symbol Conditions System Parameters (Note3) Test Circuit Figure 2 VIN=12V, ILOAD=0.5A Output Voltage VOUT Circuit of Figure 2 Output Voltage Efficiency VOUT 8V VIN 40V, 0.5A ILOAD 3A Circuit of Figure 2 VIN=12V, ILOAD=3A Min Typ Max Unit 4.9 5.0 5.1 V 4.80/4.75 5.0 5.20/5.25 V 77 % S5ULM2576-12 Electrical Characteristics Specifications with standard type face are for TJ=25 , and those with boldface type apply over full operating temperature range Parameter Symbol Conditions Min System Parameters (Note3) Test Circuit Figure 2 VIN=25V, ILOAD=0.5A Output Voltage VOUT 11.76 Circuit of Figure 2 15V VIN 40V, 0.5A ILOAD 3A 11.52/11.40 Output Voltage VOUT Circuit of Figure 2 Efficiency VIN=15V, ILOAD=3A Typ Max Unit 12 12.24 V 12 12.48/12.60 V 88 % S5ULM2576-15 Electrical Characteristics Specifications with standard type face are for TJ=25 , and those with boldface type apply over full operating temperature range Parameter Symbol Conditions Min System Parameters (Note3) Test Circuit Figure 2 VIN=25V, ILOAD=0.5A Output Voltage VOUT 14.70 Circuit of Figure 2 18V VIN 40V, 0.5A ILOAD 3A 14.40/14.25 Output Voltage VOUT Circuit of Figure 2 Efficiency VIN=18V, ILOAD=3A Typ Max Unit 15 15.30 V 15 15.60/15.75 V 88 % S5ULM2576 Electrical Characteristics Specifications with standard type face are for TJ=25 , and those with boldface type apply over full operating temperature range Parameter Symbol Conditions System Parameters (Note3) Test Circuit Figure 2 VIN=12V, ILOAD=0.5A, VOUT=5V Output Voltage VOUT Circuit of Figure 2 8V VIN 40V, 0.5A ILOAD 3A Output Voltage VOUT VOUT=5V, Circuit of Figure 2 Efficiency VIN=12V, ILOAD=3A, VOUT=5V h tp://www.SeCoSGmbH.com/ 01-Jun-2002 Rev. A Min Typ Max Unit 1.217 1.230 1.243 V 1.193/1.180 1.230 1.267/1.280 V 77 % Any changing of specification will not be informed individual Page 3 of 8 S5ULM2576 Simple Switcher Elektronische Bauelemente 3A Step-Down Voltage Regulator All Output Voltage Version Electrical Characteristics Specifications with standard type face are for TJ=25 , and those with boldface type apply over full operating temperature range. Unless otherwise specified, VIN=12V for the 3.3V, 5.0V and Adjustable versions, VIN=25V for 12V version, and VIN=30V for 15V version. ILOAD=0.5A Parameter Feedback bias current Oscillator frequency Saturation voltage Symbol Min 47/42 Typ 50 52 Max 100/500 58/63 Unit nA kHz - 1.4 1.8/2.0 V 93 98 4.2/3.5 5.8 6.9/7.5 (Note 6, 7) Output=0V Output=-1V (Note 6) - 7.5 5 2 30 10 mA ISTBY ON/OFF pin=5V (OFF) - 50 200 uA 2.2/2.4 1.4 - Ib fO VSAT Conditions VOUT=5V (adjustable version only) (Note 8) ILOAD=3A (Note 4) Maximum duty cycle (ON) DC (Note 5) Current limit ICL (Note 4, 8) Output leakage current IL Quiescent current Standby quiescent current IQ % A mA ON/OFF Control ON/OFF pin logic input VIH VOUT=0V level VIL VOUT=Nominal output voltage - 1.2 1.0/0.8 ON/OFF pin input IIH ON/OFF pin=5V (OFF) - 12 30 current IIL ON/OFF pin=0V (ON) - 0 10 V uA Note 1: Absolute Maximum Rating indicate limits beyond which damage to the device may occur. Operating Rating indicate conditions for which the device is intended to be functional, but do not guaranteed specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. Note 2: All limits guaranteed at room temperature (standard type face) and at temperature extremes (bold type face). Note 3: External component such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the G5ELM2576 is used as shutdown 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: 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 protection feature lowers the average power dissipation of the IC by lowering the minimum duty cycle from 5% down to approximately 2%. http://www.SeCoSGmbH.com/ 01-Jun-2002 Rev. A Any changing of specification will not be informed individual Page 4 of 8 S5ULM2576 Elektronische Bauelemente Simple Switcher 3A Step-Down Voltage Regulator Typical Performance Characteristics (circuit of Figure 1) Normalized Output Voltage Line Regulator Dropout Voltage Standby Quiescent Current Quiescent Current http://www.SeCoSGmbH.com/ 01-Jun-2002 Rev. A Current Limit Any changing of specification will not be informed individual Page 5 of 8 S5ULM2576 Simple Switcher Elektronische Bauelemente 3A Step-Down Voltage Regulator Description GND Typically a large storage capacitor is connected from this pin to ground to insure that the input 1.3V or open= output enable. tage does not sag below the minimum dropout voltage during the load V higher than Vout in order for the device to NC Switch Saturation Voltage Efficiency Oscillator Frequency Minimum Operating voltage Quiescent Current vs Duty Cycle http://www.SeCoSGmbH.com/ 01-Jun-2002 Rev. A Feedback Voltage vs Duty Cycle Any changing of specification will not be informed individual Page 6 of 8 S5ULM2576 Simple Switcher Elektronische Bauelemente 3A Step-Down Voltage Regulator Minimum Power Dissipation Feedback Pin Current Output Voltage Change Load Current Switching Waveforms Load Transient Response 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: 5us/div h tp://www.SeCoSGmbH.com/ 01-Jun-2002 Rev. A Any changing of specification will not be informed individual Page 7 of 8 S5ULM2576 Simple Switcher Elektronische Bauelemente 3A Step-Down Voltage Regulator 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. S5ULM2576 Cin-- 100uF, 75V, Aluminum Electrolytic Cout-- 1000uF, 25V Aluminum Electrolytic D1-- Schottky, MBR360 L1-- 100uH, Pulse Eng, PE92108 R1-- 2k, 0.1% R1-- 6.12k, 0.1% S5ULM2576 Vout=VREF*(1+R2/R1) R2=R1*(Vout/VREF-1) Where VREF=1.23V, R1 between 1k and 5k http://www.SeCoSGmbH.com/ 01-Jun-2002 Rev. A Figure 1 Any changing of specification will not be informed individual Page 8 of 8