L5970

L5970D STMICROELECTRONICS | Alldatasheet

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Technical content

■ 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 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 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 ex- ternal 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 fre- quency modulation offers an effective constant current short circuit protection. SO8 ORDERING NUMBERS: L5970D (SO8) L5970D013TR (T&R) UP TO 1A STEP DOWN SWITCHING REGULATOR TEST APPLICATION CIRCUIT D98IN954C L5970D 10mF 35V CERAMIC 100mF 10V VOUT=3.3V VIN = 4.4V to 35V 5.6K 3.3KR3 4.7K 22nF 220pF STPS2L40U 3.3V INH. SYNC. COMP VCC VREF OUT FB GND L1 33mH

PINS CONNECTION (Top View) PINS FUNCTION THERMAL DATA (*) Package mounted on board ABSOLUTE MAXIMUM RATINGS N. Name Description 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. REF 3.3V VREF. No cap is requested for stability. 7 GND Ground. 8V CC Unregulated DC input voltage. Symbol Parameter Value Unit R th (j-amb)Thermal Resistance Junction to ambient Max. 120 (*) °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 0.75 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 CHARACTERISTCS (Tj = 25°C, VCC = 12V, unless otherwise specified.) (*) Specification Referred to Tj from -40 to +125°C (1). Note (1): Specification over the -40 to +125 Tj Temperature range are assured by design, characterization and statistical correlation. Note (2): Guaranteed by design. Symbol Parameter Test Condition Min. Typ. Max. Unit VCC Operating input voltage range Vo = 1.235V; Io = 1A * 4.4 36 V Vd Dropout voltage V CC = 4.4V; Io = 1A * 0.25 0.5 V Il Maximum limiting current V CC = 4.4V to 36V * 1.5 1.87 2.25 A fs Switching frequency * 212 250 280 KHz 225 250 275 KHz Duty cycle 0 100 % DYNAMIC CHARACTERISTICS (see test circuit fig. xx note 1). V5 Voltage feedback 4.4V < V CC < 36V, 20mA < IO < 1A 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; VFB = 1.5V 2.5 mA Iqst-by Total stand-by quiescent current Vinh > 2.2V VCC = 36V; Vinh > 2.2V 100 150 µA µA INHIBIT INH Threshold voltage Device ON 0.8 V Device OFF 2.2 V ERROR AMPLIFIER V OH High level output voltage VFB = 1V 3.5 V VOL Low level output voltage V FB = 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 65 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 Vsync = 0.74V (2) 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

DIM. mm inch A 1.75 0.069 a1 0.1 0.25 0.004 0.010 a2 1.65 0.065 a3 0.65 0.85 0.026 0.033 b 0.35 0.48 0.014 0.019 b1 0.19 0.25 0.007 0.010 C 0.25 0.5 0.010 0.020 c1 45 ° (typ.) D (1) 4.8 5.0 0.189 0.197 E 5.8 6.2 0.228 0.244 e 1.27 0.050 e3 3.81 0.150 F (1) 3.8 4.0 0.15 0.157 L 0.4 1.27 0.016 0.050 M 0.6 0.024 S8 ° (max.) (1) D and F do not include mold flash or protrusions. Mold flash or potrusions shall not exceed 0.15mm (.006inch). SO8 OUTLINE AND MECHANICAL DATA

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 L5970D