L6925D HIGH EFFICIENCY MONOLITHIC SYNCHRONOUS STEP DOWN REGULATOR 1 ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ FEATURES Figure 1. Package 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 Table 1. Order Codes 2 ■ ■ ■ ■ ■ Package L6925D MSOP8 (Tube) L6925D013TR 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 noise-sensitive applications. 1.1 APPLICATIONS ■ Part Number BATTERY-POWERED EQUIPMENTS PORTABLE INSTRUMENTS CELLULAR PHONES PDAs AND HAND HELD TERMINALS DSC GPS 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. Figure 2. Application Test Circuit VIN=2.7V to 5.5V C1 10µF 6.3V SYNC R2 600K R1 100K VCC LBI LBO September 2004 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 Rev. 3 1/6 L6925D Table 2. Absolute Maximum Ratings Symbol Parameter Value Unit V6 Input voltage -0.3 to 6 V V5 Output switching voltage -1 to VCC V V1, V8 Low Battery Input, Low Battery Output -0.3 to VCC V V3 Feedback voltage -0.3 to VCC V V2 Error Amplifier Output Voltage -0.3 to VCC V V7 Syncronization / Mode Selector -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’ Figure 3. Pin Connection LBI 1 8 LBO COMP 2 7 SYNC VFB 3 6 VCC GND 4 5 LX D01IN1239A/mod Table 3. Thermal Data Symbol Rth j-amb Parameter Thermal Resistance Junction to Ambient Table 4. Pin Functions 2/6 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 Table 5. 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 3/6 L6925D Figure 4. MSOP8 Mechanical Data & Package Dimensions 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 0.850 0.650 0.400 0.550 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 Note: 1. D and F does not include mold flash or protrusions. Mold flash or potrusions shall not exceed 0.15mm (.006inch) per side. 4/6 OUTLINE AND MECHANICAL DATA MSOP8 (Body 3mm) L6925D Table 6. Revision History Date Revision Description of Changes January 2004 2 First Issue in EDOCS DMS September 2004 3 Changed Style-sheet and Table 2 5/6 L6925D Information furnished is believed to be accurate and reliable. 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