L5973D 2.5A SWITCH STEP DOWN SWITCHING REGULATOR L5973D

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Matilda Stanley
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1 .A SWITCH STEP DOWN SWITCHING REGULATOR.A INTERNAL SWITCH OPERATING INPUT VOLTAGE FROM.V TO 3V 3.3V / (±%) REFERENCE VOLTAGE PUT VOLTAGE ADJUSTABLE FROM.3V TO 3V LOW DROP OPERATION: 00% DUTY CYCLE 0KHz INTERNALLY FIXED FREQUENCY VOLTAGE FEEDFORWARD ZERO LOAD CURRENT OPERATION INTERNAL CURRENT LIMITING IBIT FOR ZERO CURRENT CONSUMPTION SYNCHRONIZATION PROTECTION AGAINST FEEDBACK DISCONNECTION THERMAL SHUTDOWN APPLICATIONS: CONSUMER: STB, DVD, TV, VCR,CAR RADIO, LCD MONITORS NETWORKING: XDSL, MODEMS,DC-DC MODULES UTER: PRINTERS, AUDIO/GRAPHIC CARDS, OPTICAL STORAGE, HARD DISK DRIVE INDUSTRIAL: CHARGERS, CAR BATTERY DC-DC CONVERTERS HSOP - EXPOSED PAD ORDERING NUMBERS: L973D (Tube) L973D03TR (T & R) DESCRIPTION The L973D is a step down monolithic power switching regulator with a minimum switch current limit of.a so it is able to deliver more than A DC current to the load depending on the application conditions. The output voltage can be set from.3v to 3V. The high current level is also achieved thanks to an SO package with exposed frame, that allows to reduce the R th(j-amb) down to approximately 0 C/W The device uses an internal P-Channel D-MOS transistor (with a typical Rdson of 0mΩ) as switching element to minimize the size of the external components. An internal oscillator fixes the switching frequency at 0KHz. Having a minimum input voltage of.v only, it is particularly suitable for V 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. TEST APPLICATION CIRCUIT VIN =.V to 3V C 0µF 3V CERAMIC VREF 3.3V C nf C3 0pF VCC SYNC. R3.7K L973D 3 7 L µh D STPS30U R.K R 3.3K V=3.3V C 330µF 0V D03IN39 September 003 /0

2 PIN CONNECTION VCC SYNC 7 3 VREF D9IN9 PIN DESCRIPTION N Pin Function Regulator Output. SYNC Master/slave synchronization. 3 A logical signal (active high) disables the device. If 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.3v. An external resistive divider is required for higher output voltages. VREF 3.3V V REF. No cap is requested for stability. 7 Ground. VCC Unregulated DC input voltage. THERMAL DATA Symbol Parameter Value Unit R th (j-amb) Thermal Resistance Junction to ambient Max. 0 (*) C/W (*) Package mounted on board ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value Unit V Input Voltage 0 V V Output DC voltage Output peak voltage at t = 0.µs - to 0 - to 0 I Maximum output current int. limit. V V V, V Analog pins V V 3-0.3V to V CC V SYNC -0.3 to V P tot Power dissipation at T amb 0 C. W T j Operating junction temperature range -0 to 0 C T stg Storage temperature range - to 0 C /0

3 ELECTRICAL CHARACTERISTICS (T j = C, V CC = V, unless otherwise specified.) (*) Specification Referred to Tj from -0 to C (). Symbol Parameter Test Condition Min. Typ. Max. Unit V CC Operating input voltage range V o =.3V; I o = A *. 3 V R DSON Mosfet on Resistance * Ω I l Maximum limiting current V CC =.V to 3V A f s Switching frequency * 0 0 KHz 0 7 KHz Duty cycle 0 00 % DYNAMIC CHARACTERISTICS (see test circuit ). V Voltage feedback.v < V CC < 3V,.0.3. V 0mA < I O < A * V η Efficiency V O = V, V CC = V 90 % DC CHARACTERISTICS I qop Total Operating Quiescent Current * 3 ma I q Quiescent current Duty Cycle = 0; V =.V. ma I qst-by Total stand-by quiescent current V inh >.V * 0 00 µa V CC = 3V; V inh >.V * 0 0 µa IBIT Threshold Voltage Device ON 0. V Device OFF. V ERROR AMPLIFIER V OH High level output voltage V = V 3. V V OL Low level output voltage V =.V 0. V I o source Source output current V =.9V; V = V µa I o sink Sink output current V =.9V; V =.V. ma I b Source bias current. µa DC open loop gain R L = 0 7 db gm Transconductance I comp = -0.mA to 0.mA V =.9V.3 ms SYNC FUNCTION High Input Voltage V CC =.V to 3V. V REF V Low Input Voltage V CC =.V to 3V 0.7 V Slave Sink Current V sync = 0.7V () ma V sync =.33V ma Master Output Amplitude I source = 3mA.7 3 V Output Pulse Width no load, V sync =.V µs REFERENCE SECTION Reference Voltage V I REF = 0 to ma V CC =.V to 3V * V Line Regulation I REF = 0mA 0 mv V CC =.V to 3V Load Regulation I REF = 0 to ma mv Short Circuit Current 0 30 ma Notes:. Specification over the -0 to + Tj Temperature range are assured by design, characterization and statistical correlation.. Guaranteed by design. 3/0

4 Figure. Line Regulation Vo (V) Vcc = V Vo = 3.3V Tj = C Tj = C Vcc (V) Figure. Output Voltage vs. Junction Temperature Vo (V) Vcc = V Vcc=V Tj ( C) Figure. Shutdown Current vs.junction Temperature Ishd (µa) Tj ( C) Figure. Switching Frequency vs.junction Temperature Fsw (KHz) Vcc = V Vcc = V Vo = 3.3V Tj ( C) Figure 3. Quiescent Current vs. Junction Temperature Iq (ma)... Vcc = V DC = 0% Tj ( C) /0

5 APPLICATION CIRCUIT In figure is shown the demo board application circuit, where the input supply voltage, V cc, can range from.v to V due to the rated voltage of the input capacitor and the output voltage is adjustable from.3v to V cc. Figure. Demo board Application Circuit VIN =.V to V C 0µF V CERAMIC 3.3V C nf C3 0pF VREF VCC SYNC. R3.7K L973D 3 7 L µh D STPSLU R.K R 3.3K V=3.3V C 330µF.3V D03IN0 Table. Component List Reference Part Number Description Manufacturer C 0µF, V TOKIN C POSCAP TPB330M 330µF,.3V Sanyo C3 C0CJGAC 0pF, %, 0V KEMET C C0C3KRAC nf, 0%, 0V KEMET R.K, %, 0.W 003 Neohm R 3.3K, %, 0.W 003 Neohm R3.7K, %, 0.W 003 Neohm D STPSLU A, V ST L DO33P-3 µh, 3A COILCRAFT /0

6 Figure 7. PCB layout (component side) mm 3mm Figure. PCB layout (bottom side) Figure 9. PCB layout (front side) Below some graphs show the Tj versus output current in different conditions of the input and output voltage and some efficiency measurements. /0

7 Figure 0. Junction Temperature vs. Output Current Tj( C) Vin=V Tamb= C Vo=3.3V Vo=.V Vo=.V Io(A) Figure. Efficiency vs. Output Current Efficiency (%) Vin=V Vo=.V Vo=.V Vo=3.3V Io (A) Figure. Junction Temperature vs. Output Current Tj ( C) Vin=V Tamb= C Vo=V Vo=3.3V Vo=.V Io (A) Figure 3. Efficiency vs. Output Current Efficiency (%) Vo=V 3 Vo=3.3V Vo=.V Vin=V Io (A) 7/0

8 APPLICATION IDEAS Figure. Positive Buck-Boost regulator VIN=V C 0uF 0V Ceramic C 0pF C3 nf R3.7k Vcc SYNC VREF L973D 3.3V 7 3 D STPSLU L uh M STNNE03L D STPSLU k.7k V=V/0.A C 00uF V Figure. Buck-Boost regulator VIN=V C 0uF 0V Ceramic C 0uF V Ceramic C3 0pF C nf R3.7k Vcc SYNC VREF L973D 3.3V 7 3.7k k L uh D STPSLU C 00uF V V=-V/0.A Figure. Dual output voltage with auxiliary winding N/N= D N V=V 0mA VIN=V C 0uF V Ceramic C 0pF C3 nf R3.7k VCC SYNC VREF L973D 3.3V 7 3 D STPSLU Lp=uH C 00uF 0V V=3.3V 0.A C 7uF 0V /0

9 mm inch DIM. MIN. TYP. MAX. MIN. TYP. MAX. A LINE AND MECHANICAL DATA A A B C D E e H h L k (min), (max) ddd () Dimension D does not include mold flash, protusions or gate burrs shall not exeed 0.mm (both side). HSOP (Exposed Pad) Exposed Pad: D = 3.mm E =.mm 790 9/0

10 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. The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners 003 STMicroelectronics - All rights reserved STMicroelectronics GROUP OF ANIES Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan - Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States 0/0

L5972D 2A SWITCH STEP DOWN SWITCHING REGULATOR L5972D

L5972D 2A SWITCH STEP DOWN SWITCHING REGULATOR L5972D A SWITCH STEP DOWN SWITCHING REGULATOR A INTERNAL SWITCH OPERATING INPUT VOLTAGE FROM.V TO 6V PUT VOLTAGE ADJUSTABLE FROM.V TO V LOW DROP OPERATION: 00% DUTY CYCLE 0KHz INTERNALLY FIXED FREQUENCY VOLTAGE