L5973D

L5973D STMICROELECTRONICS | Alldatasheet

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Technical content

■ 2.5A INTERNAL SWITCH ■ OPERATING INPUT VOLTAGE FROM 4.4V TO 36V ■ 3.3V / (±2%) REFERENCE VOLTAGE ■ OUTPUT VOLTAGE ADJUSTABLE FROM 1.235V 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 ■ SYNCHRONIZATION ■ PROTECTION AGAINST FEEDBACK DISCONNECTION ■ THERMAL SHUTDOWN APPLICATIONS: ■ CONSUMER: STB, DVD, TV, VCR,CAR RADIO, LCD MONITORS ■ NETWORKING: XDSL, MODEMS,DC-DC MODULES ■ COMPUTER: PRINTERS, AUDIO/GRAPHIC CARDS, OPTICAL STORAGE, HARD DISK DRIVE ■ INDUSTRIAL: CHARGERS, CAR BATTERY DC-DC CONVERTERS

DESCRIPTION

The L5973D is a step down monolithic power switch- ing regulator with a minimum switch current limit of 2.5A so it is able to deliver more than 2A DC current to the load depending on the application conditions. The output voltage can be set from 1.235V to 35V. The high current level is also achieved thanks to an SO8 package with exposed frame, that allows to re- duce the R th(j-amb) down to approximately 40°C/W The device uses an internal P-Channel D-MOS tran- sistor (with a typical Rdson of 250mΩ ) as switching element to minimize the size of the external compo- nents. 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 com- puter related applications. Pulse by pulse current limit with the internal frequen- cy modulation offers an effective constant current short circuit protection. HSOP8 - EXPOSED PAD ORDERING NUMBER: L5973D 2.5A SWITCH STEP DOWN SWITCHING REGULATOR TEST APPLICATION CIRCUIT D03IN1439 L5973D 10mF 35V CERAMIC 330mF 10V VOUT=3.3V VIN = 4.4V to 35V 5.6K 3.3KR3 4.7K 22nF 220pF L1 15mH STPS340U COMP VCC OUT FB GNDINH 63.3V SYNC. VREF

(*) Package mounted on board ABSOLUTE MAXIMUM RATINGS N° Pin Function 1 OUT Regulator Output. 2 SYNC Master/slave synchronization. 3 INH 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. 4 COMP E/A output for frequency compensation. 5 FB 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. 6 VREF 3.3V V REF . No cap is requested for stability. 7 GND Ground. 8 VCC Unregulated DC input voltage. Symbol Parameter Value Unit Rth (j-amb) Thermal Resistance Junction to ambient Max. 40 (*) °C/W Symbol Parameter Value Unit V8 Input Voltage 40 V V1 Output DC voltage Output peak voltage at t = 0.1µs -1 to 40 -5 to 40 V V I1 Maximum output current int. limit. V4, V5 Analog pins 4 V V3 INH -0.3V to V CC V2 SYNC -0.3 to 4 V Ptot Power dissipation at Tamb ≤ 60°C 2.25 W Tj Operating junction temperature range -40 to 150 °C Tstg Storage temperature range -55 to 150 °C OUT SYNC INH COMP VCC VREF GND FB D98IN955

ELECTRICAL CHARACTERISTICS (Tj = 25°C, VCC = 12V, unless otherwise specified.) (*) Specification Referred to Tj from -40 to 125°C (1). Notes: 1. Specification over the -40 to +125 Tj Temperature range are assured by design, characterization and statistical correlation. 2. Guaranteed by design. Symbol Parameter Test Condition Min. Typ. Max. Unit VCC Operating input voltage range Vo = 1.235V; Io = 2A * 4.4 36 V R DSON Mosfet on Resistance * 0.150 0.5 Ω Il Maximum limiting current V CC = 4.4V to 36V 2.5 3 3.5 A fs Switching frequency * 212 250 280 KHz 225 250 275 KHz Duty cycle 0 100 % DYNAMIC CHARACTERISTICS (see test circuit ). V5 Voltage feedback 4.4V < V CC < 36V, 20mA < IO < 2A 1.220 1.235 1.25 V * 1.198 1.235 1.272 V η Efficiency V O = 5V, VCC = 12V 90 % DC CHARACTERISTICS Iqop Total Operating Quiescent Current *3 5 m A Iq Quiescent current Duty Cycle = 0; V FB = 1.5V 2.5 mA Iqst-by Total stand-by quiescent current Vinh > 2.2V * 50 100 µA VCC = 36V; Vinh > 2.2V * 80 150 µA INHIBIT INH Threshold Voltage Device ON 0.8 V Device OFF 2.2 V ERROR AMPLIFIER VOH High level output voltage VFB = 1V 3.5 V VOL Low level output voltage VFB = 1.5V 0.4 V Io source Source output current V COMP = 1.9V; VFB = 1V 200 300 µA Io sink Sink output current V COMP = 1.9V; VFB = 1.5V 1 1.5 mA Ib Source bias current 2.5 4 µA DC open loop gain R L = ∞ 50 57 dB gm Transconductance I comp = -0.1mA to 0.1mA VCOMP = 1.9V 2.3 mS SYNC FUNCTION High Input Voltage V CC = 4.4V to 36V 2.5 V REF V Low Input Voltage V CC = 4.4V to 36V 0.74 V Slave Sink Current V sync = 0.74V Vsync = 2.33V 0.11 0.21 0.25 0.45 mA mA Master Output Amplitude I source = 3mA 2.75 3 V Output Pulse Width no load, V sync = 1.65V 0.20 0.35 µs REFERENCE SECTION Reference Voltage 3.234 3.3 3.366 V IREF = 0 to 5mA VCC = 4.4V to 36V * 3.2 3.3 3.399 V Line Regulation I REF = 0mA VCC = 4.4V to 36V 51 0 m V Load Regulation I REF = 0 to 5mA 8 15 mV Short Circuit Current 10 8 30 mA

to 25V due to the rated voltage of the input capacitor and the output voltage is adjustable from 1.235V to Vcc. Figure 6. Demo board Application Circuit Table 1. Component List

DIM. mm inch A 1.350 1.750 0.531 0.069 0.100 0.250 0.004 0.010 1.100 1.650 0.043 0.065 0.330 0.510 0.013 0.020 0.190 0.250 0.07 0.010 4.800 5.000 0.189 0.197 3.800 4.000 0.150 0.157 1.270 0.05 5.800 6.200 0.228 0.244 0.250 0.500 0.010 0.020 0.400 1.270 0.016 0.05 k 0˚ (min), 8˚ (max) ddd 0.100 0.010 (1) Dimension D does not include mold flash, protusions or gate burrs shall not exeed 0.15mm (both side). HSOP8 7195016 (Exposed Pad) B C D E e H h L Exposed Pad: D1 = 3.1mm E1 = 2.41mm

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  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 L5973D