L6925D STMicroelectronics

L6925D HIGH EFFICIENCY MONOLITHIC SYNCHRONOUS STEP DOWN REGULATOR 1FEATURES Figure 1. Package 2.7V TO 5.5V BATTERY INPUT RANGE HIGH EFFICIENCY: UP TO 95% INTERNAL SYNCHRONOUS SWITCH MSOP8 NO EXTERNAL SCHOTTKY REQUIRED EXTREMELY LOW QUIESCENT CURRENT Table 1. Order Codes 800mA MAX OUTPUT CURRENT Part Number Package ADJUSTABLE OUTPUT VOLTAGE FROM 0.6V L6925D MSOP8 (Tube) LOW DROP-OUT OPERATION: UP TO100% DUTY CYCLE L6925D013TR Tape & Reel SELECTABLE LOW NOISE/LOW CONSUMPTION MODE AT LIGHT LOAD 2DESCRIPTION LOW BATTERY INPUT The device is dc-dc monolithic regulator specifically LOW BATTERY OUTPUT designed to provide extremely high efficiency. 1% OUTPUT VOLTAGE ACCURACY The device has on UVLO set at 2.7V cause it is part- CURRENT-MODE CONTROL icurarly thought for single Li-ion cell applications. Output voltage can be selected by an external divider 600kHz SWITCHING FREQUENCY down to 0.6V. Duty Cycle can saturate to 100% al- EXTERNALLY SYNCHRONIZABLE FROM lowing low drop-out operation. 500kHz TO 1.4MHz The device is based on a 600kHz fixed-frequency, OVP current mode-architecture. Low Consumption Mode SHORT CIRCUIT PROTECTION operation can be selected at light load conditions, al- lowing switching losses to be reduced. L6925D is ex- 1.1 APPLICATIONS ternally synchronizable with a clock which makes it useful in noise-sensitive applications. BATTERY-POWERED EQUIPMENTS LBI pin can be used to have a LBO signal when the PORTABLE INSTRUMENTS Battery voltage is lower than a preset value. Other CELLULAR PHONES features like, Overvoltage protection, Shortcircuit PDAs AND HAND HELD TERMINALS protection and Thermal Shutdown (150C) are also DSC present. GPS Figure 2. Application Test Circuit V =2.7V to 5.5V SYNC IN L 6.8H 7 V =1.8V OUT V 5 CC C1 R2 6 LX R4 C4 10F 600K LBI 200K 10F 6.3V 1 6.3V VFB R1 3 8 100K LBO 24 R3 COMP GND 100K C2 220pF D01IN1238B Rev. 3 September 2004 1/6L6925D Table 2. Absolute Maximum Ratings Symbol Parameter Value Unit V Input voltage -0.3 to 6 V 6 V Output switching voltage -1 to V V 5 CC V , V Low Battery Input, Low Battery Output -0.3 to V V 1 8 CC V Feedback voltage -0.3 to V V 3 CC V Error Amplifier Output Voltage -0.3 to V V 2 CC V Syncronization / Mode Selector -0.3 to V V 7 CC P Power dissipation at Tamb=70C0.45W tot T Junction operating temperature range -40 to 150 C j T Storage temperature range -65 to 150 C stg LX Pin Maximum Withstanding Voltage Range Test Condition: CDF- 1000 V AEC-Q100-002- Human Body Model Acceptance Criteria: Other pins 2000 V Normal Performance Figure 3. Pin Connection LBI 1 8 LBO COMP 2 7 SYNC VFB 3 6 V CC GND4L5X D01IN1239A/mod Table 3. Thermal Data Symbol Parameter Value Unit R Thermal Resistance Junction to Ambient 180 C/W th j-amb Table 4. Pin Functions 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 Error amplifier output. Compensate it with a 220pF capacitor 3 VFB Error amplifier input. The output voltage can be adjusted by using an external resistor divider connected to this pin (V = 0.6V). FB 4 GND Ground. 5 LX Switch node connection to the inductor. 6 VCC Input voltage. 7 SYNC This pin allows to select Low Noise/ Low Consumption Mode or to sychronize the device. 8LBO 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 2/6