L6925

L6925D HIGH EFFICIENCY MONOLITHIC SYNCHRONOUS STEP DOWN REGULATOR s s s s s s s s s s s s s s s s s 2.7V TO 5.5V BATTERY INPUT RANGE HIGH EFFICIENCY: UP TO 95% INTERNAL SYNCHRONOUS SWITCH NO EXTERNAL SCHOTTKY REQUIRED EXTREMELY LOW QUIESCENT CURRENT 800mA MAX OUTPUT CURRENT ADJUSTABLE OUTPUT VOLTAGE FROM 0.6V LOW DROP-OUT OPERATION: UP TO100% DUTY CYCLE SELECTABLE LOW NOISE/LOW CONSUMPTION MODE AT LIGHT LOAD LOW BATTERY INPUT LOW BATTERY OUTPUT ±1% OUTPUT VOLTAGE ACCURACY CURRENT-MODE CONTROL 600kHz SWITCHING FREQUENCY EXTERNALLY SYNCHRONIZABLE FROM 500kHz TO 1.4MHz OVP SHORT CIRCUIT PROTECTION MSOP8 ORDERING NUMBERS: L6925D (Tube) L6925013TR (Tape & Reel) DESCRIPTION The device is dc-dc monolithic regulator specifically designed to provide extremely high efficiency. The device has on UVLO set at 2.7V cause it is particurarly thought for single Li-ion cell applications. Output voltage can be selected by an external divider down to 0.6V. Duty Cycle can saturate to 100% allowing low drop-out operation. The device is based on a 600kHz fixed-frequency, current mode-architecture. Low Consumption Mode operation can be selected at light load conditions, allowing switching losses to be reduced. L6925D is externally synchronizable with a clock which makes it useful in noisesensitive applications. LBI pin can be used to have a LBO signal when the Battery voltage is lower than a preset value. Other features like, Overvoltage protection, Shortcircuit protection and Thermal Shutdown (150°C) are also present. APPLICATIONS s BATTERY-POWERED EQUIPMENTS s PORTABLE INSTRUMENTS s CELLULAR PHONES s PDAs AND HAND HELD TERMINALS s DSC s GPS APPLICATION TEST CIRCUIT VIN=2.7V to 5.5V C1 10µF 6.3V R2 600K R1 100K SYNC VCC LBI 7 6 1 8 COMP L 6.8µH 5 LX R4 200K VOUT=1.8V C4 10µF 6.3V 3 2 C2 220pF 4 GND VFB R3 100K LBO D01IN1238B September 2003 1/5 L6925D ABSOLUTE MAXIMUM RATINGS Symbol V6 V5 V1 V3 V2 Ptot Tj Tstg LX Pin Other pins Input voltage Output switching voltage Shutdown Feedback voltage Analog input voltage Power dissipation at Tamb=70°C Junction operating temperature range Storage temperature range Maximum Withstanding Voltage Range Test Condition: CDFAEC-Q100-002- “Human Body Model” Acceptance Criteria: “Normal Performance’ Parameter Value -0.3 to 6 -1 to VCC -0.3 to VCC -0.3 to VCC -0.3 to VCC 0.45 -40 to 150 -65 to 150 ±1000 ±2000 Unit V V V V V W °C °C V V PIN CONNECTION LBI COMP VFB GND 1 2 3 4 D01IN1239A/mod 8 7 6 5 LBO SYNC VCC LX THERMAL DATA Symbol Rth j-amb Parameter Thermal Resistance Junction to Ambient Value 180 Unit °C/W PIN FUNCTIONS N 1 2 3 4 5 6 7 8 Name LBI COMP VFB GND LX VCC SYNC LBO Description Battery low voltage detector input. The internal threshold is set to 0.6V. The external threshold can be adjusted by using an external resistor divider. Error amplifier output. Compensate it with a 220pF capacitor Error amplifier input. The output voltage can be adjusted by using an external resistor divider connected to this pin (VFB = 0.6V). Ground. Switch node connection to the inductor. Input voltage. This pin allows to select Low Noise/ Low Consumption Mode or to sychronize the device. Battery low voltage detector output. If the voltage at the LBI pin drops below the internal thrshold, LBO goes low. The LBO is an open drain output. A pull_up resistor should be connected between the pin and the output voltage 2/5 L6925D ELECTRICAL CHARACTERISTICS (TJ = 25°C, VCC = 3.6V unless otherwise specified) Symbol Vcc Vcc ON Vcc OFF Vcc hys Rp Rn Ilim Parameter Operating input voltage Turn On threshold Turn Off threshold Hysteresis High side Ron Low side Ron Peak current limit Valley current limit Vout fosc fsync Output voltage range Oscillator frequency Sync mode clock (*) 500 Vcc = 3.6V, Ilx =100mA Vcc = 3.6V, Ilx =100mA Vcc = 3.6V Vcc = 3.6V 0.6 600 1400 Test Condition After Turn On Min 2.7 2.8 2.65 150 240 215 1.2 1.4 Vcc Typ Max 5.5 Unit V V V mV mΩ mΩ A A V KHz KHz DC CHARACTERISTICS Iq Quiescent current (low noise mode) Quiescent current (low cunsumption mode) Ish Ilx Shutdown current LX leakage current (*) Vsync = 0V, no load, VFB > 0.6V Vsync = Vcc, no load, VFB > 0.6V Vcc < 2.7V, VFB > 0.6V Vcc < 2.7V, VLX = Vcc Vcc < 2.7V, VLX = 0V ERROR AMPLIFIER CHARACTERISTICS Vfb Ifb Voltage feedback Feedback input current (*) VFB = 0.6V 0.593 0.6 25 0.607 V nA 230 25 0.2 1 1 µA µA µA µA µA SYNC/MODE FUNCTION Vsync_H Vsync_L LB SECTION VLBI VLBO ILK-LBO LBI Threshold LBO Logic Low LBO Leakage Current (*) Isink = 1mA, Vcc = 3.6V, VLBI < 0.6V V LBO = 3.6V, Vcc = 3.6V, VLBI > 0.6V 0.6 0.2 0.4 50 V V nA Sync mode threshold high Sync mode threshold low 0.5 1.3 V V PROTECTIONS HOVP Hard overvoltage threshold 10 %Vout (*) Guaranteed by design 3/5 L6925D mm DIM. MIN. A A1 A2 b c D (1) E E1 (1) e L L1 k aaa Note: inch MAX. 1.10 MIN. TYP. MAX. 0.043 0.002 0.03 0.010 0.005 0.114 0.183 0.114 0.118 0.193 0.118 0.026 0.700 0.016 0.022 0.037 0˚ (min.) 6˚ (max.) 0.100 0.004 0.028 0.033 0.006 0.037 0.016 0.009 0.122 0.20 0.122 TYP. OUTLINE AND MECHANICAL DATA 0.050 0.750 0.250 0.130 2.900 4.650 2.900 3.000 4.900 3.000 0.650 0.400 0.550 0.950 0.850 0.150 0.950 0.400 0.230 3.100 5.150 3.100 1. D and F does not include mold flash or protrusions. Mold flash or potrusions shall not exceed 0.15mm (.006inch) per side. MSOP8 (Body 3mm) 4/5 L6925D 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 © 2003 STMicroelectronics - All rights reserved STMicroelectronics GROUP OF COMPANIES 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 www.st.com 5/5