L6925D HIGH EFFICIENCY MONOLITHIC SYNCHRONOUS STEP DOWN REGULATOR ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ 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 ■ BATTERY-POWERED EQUIPMENTS ■ PORTABLE INSTRUMENTS ■ CELLULAR PHONES ■ PDAs AND HAND HELD TERMINALS ■ DSC ■ GPS APPLICATION TEST CIRCUIT VIN=2.7V to 5.5V C1 10µF 6.3V SYNC R2 600K R1 100K VCC LBI LBO September 2003 5 6 LX 1 8 COMP D01IN1238B L 6.8µH 7 3 2 4 C2 220pF GND R4 200K VFB VOUT=1.8V C4 10µF 6.3V R3 100K 1/5 L6925D ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value Unit -0.3 to 6 V V6 Input voltage V5 Output switching voltage -1 to VCC V V1 Shutdown -0.3 to VCC V V3 Feedback voltage -0.3 to VCC V V2 Analog input voltage -0.3 to VCC V Ptot Power dissipation at Tamb=70°C 0.45 W Tj Junction operating temperature range -40 to 150 °C Storage temperature range -65 to 150 °C ±1000 V ±2000 V Value Unit 180 °C/W Tstg LX Pin Other pins Maximum Withstanding Voltage Range Test Condition: CDFAEC-Q100-002- “Human Body Model” Acceptance Criteria: “Normal Performance’ PIN CONNECTION LBI 1 8 LBO COMP 2 7 SYNC VFB 3 6 VCC GND 4 5 LX D01IN1239A/mod THERMAL DATA Symbol Rth j-amb Parameter Thermal Resistance Junction to Ambient PIN FUNCTIONS 2/5 N Name Description 1 LBI 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. 2 COMP 3 VFB Error amplifier input. The output voltage can be adjusted by using an external resistor divider connected to this pin (VFB = 0.6V). 4 GND Ground. 5 LX 6 VCC 7 SYNC This pin allows to select Low Noise/ Low Consumption Mode or to sychronize the device. 8 LBO 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 Error amplifier output. Compensate it with a 220pF capacitor Switch node connection to the inductor. Input voltage. L6925D ELECTRICAL CHARACTERISTICS (TJ = 25°C, VCC = 3.6V unless otherwise specified) Symbol Vcc Parameter Operating input voltage Test Condition After Turn On Min Typ 2.7 Max Unit 5.5 V Vcc ON Turn On threshold 2.8 V Vcc OFF Turn Off threshold 2.65 V Vcc hys Hysteresis 150 mV Rp High side Ron Vcc = 3.6V, Ilx =100mA 240 mΩ Rn Low side Ron Vcc = 3.6V, Ilx =100mA 215 mΩ Ilim Peak current limit Vcc = 3.6V 1.2 A Valley current limit Vcc = 3.6V 1.4 A Vout Output voltage range fosc Oscillator frequency fsync Sync mode clock (*) 0.6 Vcc 600 500 V KHz 1400 KHz DC CHARACTERISTICS Quiescent current (low noise mode) Vsync = 0V, no load, VFB > 0.6V 230 µA Quiescent current (low cunsumption mode) Vsync = Vcc, no load, VFB > 0.6V 25 µA Ish Shutdown current Vcc < 2.7V, VFB > 0.6V 0.2 µA Ilx LX leakage current (*) Vcc < 2.7V, VLX = Vcc 1 µA Vcc < 2.7V, VLX = 0V 1 µA Iq ERROR AMPLIFIER CHARACTERISTICS Vfb Voltage feedback Ifb Feedback input current (*) 0.593 VFB = 0.6V 0.6 0.607 25 V nA SYNC/MODE FUNCTION Vsync_H Sync mode threshold high Vsync_L Sync mode threshold low 1.3 0.5 V V LB SECTION VLBI LBI Threshold VLBO LBO Logic Low Isink = 1mA, Vcc = 3.6V, VLBI < 0.6V LBO Leakage Current (*) V LBO = 3.6V, Vcc = 3.6V, VLBI > 0.6V ILK-LBO 0.6 0.2 V 0.4 V 50 nA PROTECTIONS HOVP Hard overvoltage threshold 10 %Vout (*) Guaranteed by design 3/5 L6925D mm inch DIM. MIN. TYP. A MAX. MIN. TYP. 1.10 A1 0.050 A2 0.750 b MAX. 0.043 0.150 0.002 0.950 0.03 0.250 0.400 0.010 0.016 c 0.130 0.230 0.005 0.009 D (1) 2.900 3.000 3.100 0.114 0.118 0.122 E 4.650 4.900 5.150 0.183 0.193 0.20 E1 (1) 2.900 3.000 3.100 0.114 0.118 0.122 e L L1 k aaa Note: 4/5 0.850 0.650 0.400 0.550 OUTLINE AND MECHANICAL DATA 0.006 0.033 0.037 0.026 0.700 0.016 0.950 0.022 0.028 0.037 0˚ (min.) 6˚ (max.) 0.100 0.004 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) 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