L5970

L5970D UP TO 1A STEP DOWN SWITCHING REGULATOR s s s s s s s s s s s s s UP TO 1A OUTPUT CURRENT OPERATING INPUT VOLTAGE FROM 4.4V TO 36V 3.3V / (±2%) / REFERENCE VOLTAGE OUTPUT VOLTAGE ADJUSTABLE FROM 1.2V TO 35V LOW DROPOUT OPERATION: 100% DUTY CYCLE 250KHz INTERNALLY FIXED FREQUENCY VOLTAGE FEEDFORWARD ZERO LOAD CURRENT OPERATION INTERNAL CURRENT LIMITING INHIBIT FOR ZERO CURRENT CONSUMPTION SINCHRONIZATION PROTECTION AGAINST FEEDBACK DISCONNECTION THERMAL SHUTDOWN SO8 ORDERING NUMBERS: L5970D (SO8) L5970D013TR (T&R) DESCRIPTION The L5970D is a step down monolithic power switching regulator capable to deliver up to 1A at output voltages from 1.2V to 35V. The device uses an internal P-Channel D-MOS transistor (with a typical Rdson of 250mΩ) as switching element to minimize the size of the external components. An internal oscillator fixes the switching frequency at 250KHz. Having a minimum input voltage of 4.4V only, it is particularly suitable for 5V bus, available in all computer related applications. Pulse by pulse current limit with the internal frequency modulation offers an effective constant current short circuit protection. APPLICATIONS: s CONSUMER: STB, DVD, TV, VCR,CAR RADIO, LCD MONITORS s NETWORKING: XDSL, MODEMS,DC-DC MODULES s COMPUTER: PRINTERS, AUDIO/GRAPHIC CARDS, OPTICAL STORAGE, HARD DISK DRIVE s INDUSTRIAL: CHARGERS, CAR BATTERY DC-DC CONVERTERS TEST APPLICATION CIRCUIT 3.3V VIN = 4.4V to 35V VREF VCC SYNC. 6 8 2 4 INH. 1 OUT L1 33µH D1 STPS2L40U VOUT=3.3V L5970D 3 7 5 GND FB R1 5.6K C1 10µF 35V CERAMIC COMP C4 22nF C3 220pF C2 100µF 10V R3 4.7K R2 3.3K D98IN954C May 2003 1/10 L5970D PINS CONNECTION (Top View) OUT SYNC INH COMP 1 2 3 4 D98IN955 8 7 6 5 VCC GND VREF FB PINS FUNCTION N. 1 2 3 4 5 6 7 8 Name OUT SYNC INH COMP FB VREF GND VCC Regulator Output. Master/slave synchronization. A logical signal (active high) disables the device. If INH not used the pin must be grounded. When it is open an internal pull-up disable the device. E/A output for frequency compensation. Feedback input. Connecting directly to this pin results in an output voltage of 1.23V. An external resistive divider is required for higher output voltages. 3.3V VREF. No cap is requested for stability. Ground. Unregulated DC input voltage. Description THERMAL DATA Symbol (*) Package mounted on board Parameter Value 120 (*) Unit °C/W Rth (j-amb) Thermal Resistance Junction to ambient Max. ABSOLUTE MAXIMUM RATINGS Symbol V8 V1 I1 V4, V5 V3 V2 Ptot Tj Tstg Input Voltage Output DC voltage Output peak voltage at t = 0.1µs Maximum output current Analog pins INH SYNC Power dissipation at Tamb ≤ 60°C Operating junction temperature range Storage temperature range Parameter Value 40 -1 to 40 -5 to 40 int. limit. 4 -0.3V to VCC -0.3 to 4 0.75 -40 to 150 -55 to 150 V W °C °C V Unit V V V 2/10 L5970D ELECTRICAL CHARACTERISTCS (Tj = 25°C, VCC = 12V, unless otherwise specified.) (*) Specification Referred to Tj from -40 to +125°C (1). Symbol VCC Vd Il fs Parameter Operating input voltage range Dropout voltage Maximum limiting current Switching frequency Duty cycle DYNAMIC CHARACTERISTICS (see test circuit fig. xx note 1). V5 Voltage feedback 4.4V < VCC < 36V, 20mA < IO < 1A η Efficiency VO = 5V, VCC = 12V * Duty Cycle = 0; VFB = 1.5V Vinh > 2.2V VCC = 36V; Vinh > 2.2V Device ON Device OFF VFB = 1V VFB = 1.5V VCOMP = 1.9V; VFB = 1V Vcomp = 1.9V; VFB = 1.5V RL = ∞ Icomp = -0.1mA to 0.1mA Vcomp = 1.9V VCC = 4.4V to 36V VCC = 4.4V to 36V Vsync = 0.74V Vsync = 2.33V Isource = 3mA no load, Vsync = 1.65V (2) Test Condition Vo = 1.235V; Io = 1A VCC = 4.4V; Io = 1A VCC = 4.4V to 36V * * * * Min. 4.4 Typ. Max. 36 0.5 2.25 280 275 100 1.25 1.272 Unit V V A KHz KHz % V V % 0.25 1.5 212 225 0 1.220 1.198 1.87 250 250 * 1.235 1.235 90 3 DC CHARACTERISTICS Total operating quiescent Iqop current Quiescent current Iq Iqst-by INHIBIT INH Threshold voltage ERROR AMPLIFIER High level output voltage VOH VOL Io source Io sink Ib gm Low level output voltage Source output current Sink output current Source bias current DC open loop gain Transconductance Total stand-by quiescent current 5 2.5 mA mA µA µA V V V * * 50 80 100 150 0.8 2.2 3.5 0.4 200 1 50 300 1.5 2.5 65 2.3 4 V µA mA µA dB mS SYNC FUNCTION High Input Voltage Low Input Voltage Slave Sink Current Master Output Amplitude Output Pulse Width REFERENCE SECTION Reference Voltage 2.5 0.11 0.21 2.75 0.20 3.234 3.2 3 0.35 3.3 3.3 5 8 10 8 VREF 0.74 0.25 0.45 V V mA mA V µs IREF = 0 to 5mA VCC = 4.4V to 36V Line Regulation Load Regulation Short Circuit Current IREF = 0mA VCC = 4.4V to 36V IREF = 0 to 5mA * 3.366 3.399 10 15 30 V V mV mV mA Note (1): Specification over the -40 to +125 Tj Temperature range are assured by design, characterization and statistical correlation. Note (2): Guaranteed by design. 3/10 L5970D Figure 1. Junction Temperature vs. Output Current (SO8) *) Tj(°C) Figure 4. Load Regulation Vo (V) 3.312 3.308 Vcc = 12V Vo = 3.3V Tj = 25°C 3.304 3.3 3.296 3.292 3.288 3.284 3.28 3.276 0 0.5 Io (A) 1 1.5 Tj = 125°C 130 120 110 100 90 80 70 60 50 40 30 20 0.2 Vo=3.3V Vo=2.5V Vcc=5V Tamb=25°C Vo=1.8V 0.4 0.6 0.8 Io(A) 1 1.2 1.4 1.6 Figure 5. Line Regulation Figure 2. Junction Temperature vs. Output Current (SO8) *) Tj(°C) Vo (V) 3.312 3.308 3.304 3.3 3.296 3.292 3.288 3.284 3.28 3.276 0 10 20 Vcc (V) 30 40 Tj = 125°C Vcc = 12V Vo = 3.3V Tj = 25°C 130 120 110 100 90 80 70 60 50 40 30 20 0.2 Vo=5V Vo=3.3V Vcc=12V Tamb=25°C Vo=2.5V 0.4 0.6 0.8 Io(A) 1 1.2 1.4 1.6 Figure 3. Junction Temperature vs. Output Current (SO8) *) Tj(°C) Figure 6. Output Voltage vs. Junction Temperature Vo (V) 1.25 1.24 1.23 140 Vo=18V Vo=12V 120 100 80 60 40 20 0 0.2 0.4 0.6 0.8 Io(A) Vcc=24V Tamb=25°C Vo=5V 1.22 Vcc = 12V 1.21 1.2 -50 1 1.2 1.4 Vcc=12V 0 50 Tj (°C) 100 150 *) Package mounted on demoboard 4/10 L5970D Figure 7. Quiescent Current vs. Junction Temperature Iq (mA) Figure 9. Switching Frequency vs.Junction Temperature Fsw (KHz) 260 2 1.8 250 1.6 Vcc = 12V DC = 0% 240 1.4 230 Vcc = 12V Vo = 3.3V 1.2 -50 0 50 Tj (°C) 100 150 220 -50 0 50 Tj (C) 100 150 Figure 8. Shutdown Current vs.Junction Temperature Ishd (µA) 70 60 Vcc = 12V 50 40 30 -50 0 50 Tj (°C) 100 150 5/10 L5970D Figure 10. Demoboard schematic VREF VCC SYNC. C1 10µF 25V CERAMIC COMP C4 22nF C3 220pF L1 33µH D1 STPS2L25U 5 GND FB 3.3V VIN = 4.4V to 25V 6 8 2 4 INH. 1 OUT VOUT=3.3V L5970D 3 7 R1 5.6K C2 100µF 10V R3 4.7K R2 3.3K D03IN1437 Part list demoboard Reference C1 C2 C3 C4 R1 R2 R3 D1 L1 STPS2L25U DO3316P-333 POSCAP 10TPB100M C1206C221J5GAC C1206C223K5RAC Part Number Description 10µF, 25V 100µF, 10V 220pF, 5%, 50V 22nF, 10%, 50V 5.6K, 1%, 0.1W 0603 3.3K, 1%, 0.1W 0603 4.7K, 1%, 0.1W 0603 2A, 25V 33µH, 2A Manufacturer TOKIN Sanyo KEMET KEMET Neohm Neohm Neohm STMicroelectronics COILCRAFT Figure 11. Efficiency vs. Output Current 94 92 90 88 86 84 82 80 78 76 74 72 70 0.1 Figure 12. Efficiency vs. Output Current 92 90 88 86 84 82 80 78 76 74 72 70 Vo=5V Vo=3.3V Vo=3.3V Vo=2.5V Efficiency (%) Vo=1.8V Efficiency (%) Vo=2.5V Vcc=12V Vcc=5V 0.2 0.3 0.4 0.5 0.6 Io (A) 0.7 0.8 0.9 1 0.1 0.2 0.3 0.4 0.5 0.6 Io (A) 0.7 0.8 0.9 1 6/10 L5970D Figure 13. PCB layout (component side) 42mm 34mm Figure 14. PCB layout (bottom side) Figure 15. PCB layout (front side) 7/10 L5970D APPLICATION IDEAS Figure 16. Dual output voltage with auxiliary winding N1/N2=2 D2 1N4148 VOUT1=5V 30mA VIN=12V VCC OUT Lp=22uH D1 STPS25L25U 8 COMP C1 10uF 25V Ceramic 1 U1 L5970D FB VOUT=3.3V 0.5A C4 100uF 10V C5 47uF 10V 4 2 6 GND 7 5 3 INH C2 220pF C3 22nF R3 4.7k SYNC VREF 3.3V Figure 17. Buck-Boost regulator VIN=12V VCC OUT L1 33uH 8 U1 COMP C1 10uF 25V Ceramic C2 10uF 35V C3 Ceramic 220pF 1 D1 STPS2L25U 2.7k VOUT=-12V/0.3A L5970 4 2 6 GND 7 5 3 FB C4 22nF R3 4.7k SYNC VREF INH 24k C5 100uF 16V 3.3V Vin=12V Vout=-12V Iout=0.5A Efficiency=81% Figure 18. Positive Buck-Boost regul VIN=5V L1 33uH VCC 8 U1 L5970 4 2 6 GND OUT D2 STPS2L25U VOUT=12V/0.3A 1 D1 STPS2L25U 24k COMP C1 10uF 25V Ceramic 7 5 3 FB C2 220pF C3 22nF R3 4.7k M1 STN4NE03L 2.7k SYNC VREF INH C4 100uF 16V 3.3V Vin=5V Vout=12V Iout=0.3A Efficiency=76% Figure 19. Synchronization example VIN VCC OUT V CC OUT 8 L5970D 4 2 SYNC VREF 1 FB COMP 8 L5970D 4 2 SYNC VREF 1 FB COMP 6 GND 7 5 3 6 GND 7 5 3 INH INH 8/10 L5970D DIM. MIN. A a1 a2 a3 b b1 C c1 D (1) E e e3 F (1) L M S 3.8 0.4 4.8 5.8 0.65 0.35 0.19 0.25 0.1 mm TYP. MAX. 1.75 0.25 1.65 0.85 0.48 0.25 0.5 0.026 0.014 0.007 0.010 0.004 MIN. inch TYP. MAX. 0.069 0.010 0.065 0.033 0.019 0.010 0.020 OUTLINE AND MECHANICAL DATA 45° (typ.) 5.0 6.2 1.27 3.81 4.0 1.27 0.6 8 ° (max.) 0.15 0.016 0.189 0.228 0.050 0.150 0.157 0.050 0.024 0.197 0.244 SO8 (1) D and F do not include mold flash or protrusions. Mold flash or potrusions shall not exceed 0.15mm (.006inch). 9/10 L5970D Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. STMicroelectronics acknowledges the trademarks of all companies referred to in this document. The ST logo is a registered trademark of STMicroelectronics © 2003 STMicroelectronics - All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - Canada - China - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan -Malaysia - Malta - Morocco Singapore - Spain - Sweden - Switzerland - United Kingdom - United States. http://www.st.com 10/10