SL2575 2A Step-down Voltage Switching Regulators

Transcription

1 DESCRIPTION SL2575 of regulators provides all the active functions for a step-down (buck) switching regulator, and drives 2A load with excellent line and load regulation. SL2575 is available in fixed output voltages 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. Features include internal frequency compensation and a fixes-frequency oscillator. The SL2575 is high-efficiency replacements for popular three-terminal linear regulators, and is requiring a smaller heatsink or even no heatsink. SL2575 performs well with standard inductors from several manufacturers, and simplifying the design of switch-mode power supplies. SL2575 guarantees ±4% tolerance on output voltage within specified input voltages and output load conditions, and ±10% on the oscillator frequency. External shutdown is included with 50µ A (typical) standby current. The output switch has cycle-by-cycle current limiting as well as thermal shutdown for full protection under fault conditions. FEATURES APPLICATIONS 3.3V, 5V, 12V, 15V, Adjustable output versions Adjustable output version output voltage range 1.23V to 37V ±4% max over line and load conditions 2A output current Input voltage range up to 40V Requires only 4 external components High efficiency TTL shutdown capability, low power standby mode Thermal shutdown, current limit protection Uses standard inductors 52 khz fixed frequency internal oscillator Pre-regulator for linear regulators High-efficiency step-down buck regulator On-card/ board switching regulators Positive to negative converter (buck-boost) PIN CONFIGURATION Top View 8L SOIC PACKAGE TOP MARKING: VI N V OUT Feedback On / Off GND GND GND GND SL2575 FYMXXXS VVGYWW Line 1: Device Line 2: Lot No. Code F Foundry Code (C) YMXXX 5 Character Lot No. S Split Code Line 3: Voltage + Date Code VV Voltage Output G Assembly Vendor Code Y Last digit of the Year WW Workweek ORDERING INFORMATION Circuit Type: 2A Step-Down Voltage Switching Regulators Voltage Output: AD = Adj 33 = 3.3V 50 = 5.0V 12 = 12V 15 = 15V SL D8 13 Packaging Option: T = Tube 13 = Tape and Reel (13 Reel Dia) Package Style: D8 = SOIC/8L Silicon Link Inc. 1 March 2010 Rev. 1

2 BLOCK DIAGRAM ABSOLUTE MAXIMUM RATINGS TYPICAL APPLICATIONS LOW NOISE APPLICATIONS Silicon Link Inc. 2 March 2010 Rev. 1

3 ABSOLUTE MAXIMUM RATINGS Rating Value Unit Maximum Supply Voltage 45 V ON/OFF Pin Input Voltage -0.3 V V IN V Output Voltage to Ground (Steady State) -1.0 V Power Dissipation Internally Limited - Storage Temperature Range -65 to C Maximum Junction Temperature +150 C Minimum ESD Rating (C=100pF, R=1.5k W) 2 kv Lead Temperature (Soldering, 10 seconds) +260 C OPERATING RATINGS Rating Value Unit Operating Temperature Range -40 T J 125 C Supply Voltage 40 V ELECTRICAL CHARACTERISTICS: SL (Specifications with standard type face are for T J = 25 C and those with boldface type apply over full Operating Temperature Range) Parameter Conditions Symbol Min Typ Max Unit Output Voltage V IN = 12V, I LOAD = 0.5A V OUT V Output Voltage -SL2575 6V V IN 40V, 0.5A I LOAD 2.0A V OUT 3.168/ / V Efficiency V IN = 12V, I LOAD = 2.0A η % ELECTRICAL CHARACTERISTICS: SL (Specifications with standard type face are for T JJ = 25 C and those with boldface type apply over full Operating Temperature Range) Parameter Conditions Symbol Min Typ Max Unit Output Voltage V IN = 12V, I LOAD = 0.5A V OUT V Output Voltage -SL2575 8V V IN 40V, 0.5A I LOAD 2.0A V OUT 4.800/ / V Efficiency V IN = 12V, I LOAD = 2.0A η % Silicon Link Inc. 3 March 2010 Rev. 1

4 ELECTRICAL CHARACTERISTICS: SL (Specifications with standard type face are for T J = 25 C and those with boldface type apply over full Operating Temperature Range) Parameter Conditions Symbol Min Typ Max Unit Output Voltage V IN = 25V, I LOAD = 0.5A V OUT V Output Voltage-SL V V IN 40V, 0.5A I LOAD 2.0A V OUT 11.52/ / V Efficiency V IN = 15V, I LOAD = 2.0A η % ELECTRICAL CHARACTERISTICS: SL (Specifications with standard type face are for T J =25 C and those with boldface type apply over full Operating Temperature Range) Parameter Conditions Symbol Min Typ Max Unit Output Voltage V IN = 25V, I LOAD = 0.5A V OUT V Output Voltage-SL V V IN 40V, 0.5A I LOAD 2.0A V OUT 14.40/ / V Efficiency V IN = 18V, I LOAD = 2.0A η % ELECTRICAL CHARACTERISTICS: SL2575-ADJ (Specifications with standard type face are for T J =25 C and those with boldface type apply over full Operating Temperature Range) Parameter Conditions Symbol Min Typ Max Unit Feedback Voltage V IN = 12V, I LOAD = 0.5A, V OUT = 5V V OUT V Feedback Voltage- SL2575 8V V IN 40V, 0.5A I LOAD 2.0A V OUT = 5V V OUT 1.193/ /1.280 V Efficiency V IN = 12V, I LOAD = 2.0A, V OUT = 5V η % Silicon Link Inc. 4 March 2010 Rev. 1

5 ELECTRICAL CHARATERISTICS (Specifications with standard type face are for T J = 25 C and those with boldface type apply over full Operating Temperature Range. Unless otherwise specified, V IN = 12V for the 3.3V, 5.0V and ADJ version, V IN = 25V for 12V version and V IN = 30V for 15V version. I LOAD = 500 ma) Parameter Conditions Symbol Min Typ Max Unit Feedback Bias Current V OUT = 5V (Adjustable Version Only) I b / 500 na Oscillator Frequency (Note 8) f O 47 / / 63 khz Saturation Voltage I OUT = 3A (Note 4) V SAT / 2.0 V Max Duty Cycle (ON) (Note 5) DC % Current Limit (Note 4, 8) I CL 4.2 / / 7.5 A Output Leakage Current (Notes 6, 7) Output = -1 V Output = -1 V Quiescent Current (Note 6) I Q ma Standby Quiescent Current ON/OFF Pin ON/OFF Pin = 5V (OFF) I L ma I STBY µa V OUT = 0V V IH 2.2 / V Logic Input Level V OUT = Nominal Output Voltage V IL / 0.8 V ON/OFF Pin Input Current ON/OFF Pin = 5V (OFF) ON/OFF Pin = 0V (ON) I IH µa I IL µa Note 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. 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 Statistica 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 SL2575 is used as shown in the Figure 1 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: V IN = 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 SL2575 by lowering the minimum duty cycle from 5% down to approximately 2%. Silicon Link Inc. 5 March 2010 Rev. 1

6 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. Single-point 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 SL2575, to keep the sensitive feedback wiring short. Figure 1(a). Fixed Output Voltage Versions C IN - 100µF, 75V, Aluminum Electrolytic C OUT - 680µF, 25V, Aluminum Electrolytic D1 Schottky, MBR360 L1-100µH, 3L Electronic Corp. TC-101M-3.0A-6826 R1 2k, 0.1% R2 6.12k, 0.1% Figure 1(b). Adjustable Output Voltage Versions Silicon Link Inc. 6 March 2010 Rev. 1

7 TYPICAL PERFORMANCE CHARACTERISTICS SWITCH CURRENT (A) Figure 2. Switch Saturation Voltage JUNCTION TEMPERATURE ( C) Figure 3. Current Limit JUNCTION TEMPERATURE ( C) Figure 4. Dropout Voltage INPUT VOLTAGE (V) Figure 5. Quiescent Current JUNCTION TEMPERATURE ( C) Figure 6. Standby Quiescent Current JUNCTION TEMPERATURE ( C) Figure 7. Minimum Operating Voltage Silicon Link Inc. 7 March 2010 Rev. 1

8 TYPICAL PERFORMANCE CHARACTERISTICS DUTY CYCLE (%) Figure 8. Quiescent Current vs. Duty Cycle DUTY CYCLE (%) Figure 9. Feedback Voltage vs. Duty Cycle AMBIENT TEMPERATURE ( C) Figure 10. Maximum Power Dissipation JUNCTION TEMPERATURE ( C) Figure 11. Feedback Pin Current Figure 12. Switching Waveforms Figure 13. Load Transient Response Silicon Link Inc. 8 March 2010 Rev. 1

9 Figure 14. SL Figure 15. SL Figure 16. SL PROCEDURE (Adjustable Output Voltage Versions) Given: V OUT = Regulated Output Voltage V IN(Max) = Maximum Input Voltage I LOAD(Max) = Maximum Load Current F = Switching Frequency (Fixed at 52 khz) 1. Programming Output Voltage (Selecting R1 and R2, as shown in Figure 12. and Figure 13. Use the following formula to select the appropriate resistor values. V R2 OUT = V REF ( 1+ ) where V REF = 1.23V R1 R 1 can be between 1k and 5k. (For best temperature coefficient and stability with time, use 1% metal film resistors) R2 = R1 ( -1) V REF EXAMPLE (Adjustable Output Voltage Versions) Given: Figure 17. SL2575-ADJ V OUT = 10V V IN(Max) = 25V E T = (V V OUT 1,000 I LOAD(Max) = 2A IN V OUT) V IN F(in khz) F = 52kHz V OUT 1. Programming Output Voltage (Selecting R1 and R2) V R2 OUT = 1.23 (1+ ) Select R1 = 1k R1 R2 = R1 ( V OUT -1) = 1k ( 10V -1) V REF 1.23V R 2 = 1k (8.13-1) = 7.13k, closest 1% value is 7.15k Silicon Link Inc. 9 March 2010 Rev. 1

10 LOW NOISE PERFORMANCE CHARACTERISTICS Silicon Link Inc. 10 March 2010 Rev. 1

11 8L-SOIC PACKAGE DIMENSION 8-Lead SOIC Plastic Surface Mounted Package SLI Package Code: D8 DIMENSION IN INCHES DIMENSION IN MM SYM MIN NOM MAX MIN NOM MAX A A A b c D E E e L L Ø 0* - B* 0* - B* h NOTES: 1. DIMENSION D DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. DIMENSION E1 DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. 2. COPLANARITY APPLIES TO THE TERMINALS. COPLANARITY SHALL NOT EXCEED [0.08 mm]. 3. BASED FROM JEDEC NS-012 VARIATION AA. Silicon Link Inc. 11 March 2010 Rev. 1

12 PACKAGE MECHANICAL DRAWING Surface Mountable Tape & Reel Specifications in mm (inch) (SOIC) User direction of feed Tape Size (W) D E P0 T (Max) A0, B0, K0 T1 (Max) Constant 8, 12, 16, 24mm 1.55±0.05 (.061±.002) 1.75±0.10 (.069±.004) 4.0±0.10 (.157±.004) (.016) See Note (.004) Dimensions Tape Size (W) 8 mm 12 mm B1 Max. 4.2 (.165) 8.2 (.323) D1 Min. 1.0 (.039) 1.5 (.059) F 3.5±0.05 (.138±.002) 5.5±0.05 (.217±.002) K Max. 2.4 (.094) 4.5 (.177) P2 2.0± ±.002 Variable Dimensions Components Per Package Requirement Tape Width (W) mm Cavity Pitch (P) mm Devices per Reel 7 Reel 13 Reel SOIC 8L Note: Ao Bo Ko are determined by component size. The clearance between the component and the cavity must be within 0.05 [.002] min. to 0.50 [.020] max. for 8mm tape, 0.05 [.002] min to 0.65 [.026] max for 12mm tape. Silicon Link Inc. 12 March 2010 Rev. 1

13 REEL DIMENSIONS Tape Size A Max. B Min. C D* Min. N Min. G T Max. 8mm 330 (12.992) 1.5 (.059) 13.0±0.20 (.152±.008) 20.2 (.795) 50 (1.973) 8.4± (.331±.059) (.567) 12mm 330 (12.992) 1.5 (.059) 13.0±0.20 (.152±.008) 20.2 (.795) 50 (1.973) 12.4± (.488±.078) (.567) MECHANICAL POLARIZATION SOIC-8L DEVICE User direction of feed Silicon Link Inc. 13 March 2010 Rev. 1