SDB842X SHOUDING | Alldatasheet

Document overview

  • Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
  • PDF pages: 7

Technical content

Features

Adjustable Output Voltage Up to 24V Internal 24V Power MOSFET 520kHz Frequency Built-in Over-Voltage Protection (OVP) Open Protection Programmable Soft-Start Function Thermal Shutdown Peak Current 3A,4.5A,5.5A s Under-Voltage-Lockout Over-Current Protection SOP-8(EP) Package TFT LCD Monitors Battery-Powered Equipment Set-Top Boxes DSL and Cable Modems and Routers The utilizes simple external loop compensation allowing optimization between component size, cost, and AC performance across a wide range of applications. Additional functions include an externally programmable soft-start function for easy inrush current control, internal over-voltage protection (OVP),cycle-by-cyc le current limit protection, under voltage lock-out and thermal shutdown. package. n n n

Applications

n n conv erter that incorporate internal pow er power MOSFET that supports peak currents of up to 3A/4.5A/5.5A. n n n n n n n n n n n Typical Application AGND VIN SW SS COMP PGND EN FB 6.8 Hμ 1μF SS34 10μF 47p F 51k 2.2n F 10n F 10uF VIN VOUT 3.6V~5.5V 12V/800mA 85k 10k 470 μF 470uF SDB842X SDB842X SD09/2012.1

WW: Week YY : Year YYWW Block Diagram Pin Configuration & Marking Information Top View SOP-8(EP) 1 2 3 4 5678 PGND VIN EN COMP SW SS FB AGND Shouding PWM Step-Up DC-DC Converter SDB842X SD09/2012.1 SDB842X XSDB8 Part Number Package Type Shipping Package

42 SOP-8(EP) 2,500 Units/Tape & Reel

Ordering Information

VIN, EN, FB, SS, COMP to Ground... Pin Descriptions Pin Number Name Function

1 PGND Power Ground

2 IN Supply Input. 3 EN Enable Control. Connect to a logic high level to enable the IC. Connect to a logic low level to disable the IC. When unused, connect EN pin to IN (do not leave pin floating). 4 COMP Error Amplifier Compensation Node.

5 AGND Analog Ground

Feedback Input.Connect this pin a resistor divider from the output to set the output voltage. FB is regulated to 1.262V. 7 SS Soft Start Control Input. Connect a capacitor from this pin to Ground to set soft-start timing duration. SS is discharged to ground in shutdown. SS may be left unconnected if soft start is not desired. 8 SW Switch Output. Connect this pin to the inductor and the schottky diode. To minimize EMI, minimize the PCB trace path between this pin and the input bypass capacitor. Exposed PAD Connected to gound Absolute Maximum Ratings These are stress ratings only and functional operation is not implied Exposure to absolute maximum ratings for prolonged time periods may affect device reliability All voltages are with respect to ground – 0.3V to 28V – 0.3V to 6.5V – 40 C to 150 C Storage Temperature Range – 55 C to 150 C Lead Temperature (Soldering, 10 sec) 300 C     Recommended Operating Conditions Thermal Information Parameter Package Symbol Maximum Unit Thermal Resistance (Junction to Case) SOP-8(EP) θJC 75 Thermal Resistance (Junction to Ambient) SOP-8(EP) θJA 180 ℃/W Shouding PWM Step-Up DC-DC Converter SDB842X SD09/2012.1

PARAMETER CONDITIONS MIN TYP MAX UNIT Input Voltage 2.7 5.5 V Under Voltage Lockout Threshold VIN Rising 2.5 V Under Voltage Lockout Hysteresis 200 mV VFB = 1.4V, Not Switching 0.25 0.35Quiescent Supply Current VFB = 1.0V, Switching 3 5 mA Supply Current in Shutdown EN = Ground 0.1 1 uA Switching Frequency 520 kHz Maximum Duty Cycle 85 % FB Feedback Voltage 1.237 1.262 1.287 V FB Input Current 0 80 nA FB Voltage Line Regulation VFB from 2.7V to 5.5V 0.05 0.15 %/V 4.5Switch Current Limit VIN=3.2V Duty Cycle = 70% 5.5 A 130 100Switch On Resistance mΩ Switch Leakage Current VSW = 10V, EN = Ground 15 uA Soft Start Pin Bias Current VSS = 1.2V 2 4.5 7 uA Logic High Threshold EN Pin 1.4 V Logic Low Threshold EN Pin 0.4 V EN Pull Down Resistor 1 MΩ Thermal Shutdown Temperature 160 ℃ Thermal Shutdown Hysteresis 40 ℃ Electrical Characteristic At T =25A C ,V =V =5V,,unless otherwise specified.IN EN Shouding PWM Step-Up DC-DC Converter SDB842X SD09/2012.1

Typical Operating Characteristics At T =25A C ,V =V =5V,V =0V,unless otherwise specified.IN EN FREQ Efficiency vs Input Voltage (Vo=12V) Efficiency vs Input Voltage (Vo=15V) Quiescent Current (V =1.4V)FB Quiescent Current (V =1.0V)FB Efficiency vs Output Current (Vo=12V) Efficiency vs Output Current (Vo=15V) 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 1 10 100 1000 Load Current (mA) Vin=3.6V Vin=4.2V Vin=5V 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 1 10 100 1000 Load Current (mA) Vin=3.6V Vin=4.2V Vin=5V 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 3 3.5 4 4.5 5 5.5 Input Voltage (V) 1mA 10mA 100mA 500mA 0 % 1 0 % 2 0 % 3 0 % 4 0 % 5 0 % 6 0 % 7 0 % 8 0 % 9 0 % 10 0 % 3 3. 5 4 4 .5 5 5. 5 In pu t Vo lt ag e (V) 1mA 10mA 100mA 500mA 0.05 0.1 0.15 0.2 0.25 2 3 4 5 6 In put Voltage(V) 0.5 1.5 2.5 3.5 2 3 4 5 6 Input Voltage(V) Shouding PWM Step-Up DC-DC Converter SDB842X SD09/2012.1

Typical Operating Characteristics At T =25A C ,V =V =5V,V =0V,unless otherwise specified.IN EN FREQ Output Voltage vs Output Current (Vo=12V) Output Voltage vs Output Current (Vo=15V) 10.5 11.5 12.5 0 200 400 600 800 1000 Load Current (mA) V in=4. 2V V in=5V 13.5 14.5 15.5 0 20 0 400 600 800 1000 L oad Curre nt (mA) Vin=3. 6V Vin=4. 2V Vin=5V Shouding PWM Step-Up DC-DC Converter SDB842X SD09/2012.1 The SDB842X are highly efficient step -up DC-DC

Application Information

converters that employ a currentmode,fixed frequency pulse-width modulation (PWM) architecture with excellent line and load regulation.The operate at constant switching frequency under medium to high load current conditions. At light loads, these devices operate in a pulse-skipping mode in order to improve light-load efficiency. The both offer a programmable soft- start function which minimizes inrush current d ur i n g s ta r t up . T he s of t- s t ar t pe r i od i s programmed by connecting a 10nF capacitor between SS and Ground. Operation of the soft- start function is as follows: when the IC is disabled, SS is actively discharged to Ground. Upon enabling the IC, CSS is charged with a

4.5 A current so that the voltage at SS increases

in a controlled manner. The peak inductor current is limited by the voltage at SS, so that the input current is limited until the soft-start period expires, and the regulator can achieve its full output current rating. Once the outputs achieve regulation, if the voltage at FB falls below 0.2V the controller will automatically disable, preventing the controller f r o m r u n n i n g o p e n - l o o p a n d p o t e n t i a l l y damaging the IC and load. Drive EN low to disable the IC and reduce the supply current to just 0.1 A. As with all nonsynchronous step-up DC/DC converters, the external Schottky diode provides a DC path from the input to the output in shutdown. As a result, the output drops to one diode voltage drop below the input in shutd own. The both feature integrated thermal o v e r l o a d p r o t e c t i o n . B o t h d e v i c e s a r e automatically disabled when their junction temperatures exceed 160° C, and automatically re-enable when the die temperature decreases by 40° C. Soft-Start Open Protection Shutdown Thermal Shutdown μ μ SDB842X SDB842X SDB842X

The bo th feature external adjustable output voltages of up to 24V. To program the output voltage, simply connect a resistive voltage divider between the output, FB, and GND, with resistors set according to the following equation: Where VFB is 1.262V. For optimal performance, the rectifier should be a Schottky rectifier that is rated to handle both the output voltage as well as the peak switch current. The features internal automatic over- voltage protection, when feedback voltage is higher than 115%. Setting the Output Voltage Rectifier Selection Over Voltage Protection SDB842X SDB842X Shouding PWM Step-Up DC-DC Converter SDB842X SD09/2012.1 Outline Dimension SOP-8(EP)