SY6345AAC

Application Notes: SY6345 40V, 300mA LDO Regulator General Description Features • SY6345 is an efficient, precise LDO designed for high input voltage and ultra low quiescent current applications. • SY6345 provides adjustable output voltage with +/-2% accuracy and very low drop out (300mV at 300mA). Other features include the operation stability with low ESR ceramic or tantalum capacitors due to the optimized internal compensation, over current protection and thermal shutdown. • • • • • • • • SY6345 is available in SOT23-5 package. • • Ordering Information Applications SY6435 □(□□)□ Tempera ture Code Packa ge Code Optiona l Spec Code Ordering Number SY6345AAC Package type SOT23-5 Wide input voltage range: 4V to 40V Low Dropout Voltage (300mV @ 300mA) Ultra-low quiescent current Extremely low shutdown current Stability with tantalum or ceramic capacitors Excellent load and line regulation +/-2% 0.6V reference accuracy 300mA maximum load current Enable control input Over current protection Thermal shutdown Compact SOT23-5 package Note • • • • • Battery powered Applications Automotive Applications Gateway Applications Remote Keyless Entry Systems SMPS post-regulator/ DC-DC modules Typical Applications Figure 1. Schematic Diagram AN_SY6345 Rev. 0.9 Figure 2. Dropout Characteristics Silergy Corp. Confidential- Prepared for Customer Use Only 1 AN_SY6345 Pinout (top view) SOT23-5 Top mark: YSxyz for (Device code: YS, x=year code, y=week code, z= lot number code) Function Pin Description Pin Name IN GND EN Pin Number 1 2 3 ADJ 4 OUT 5 Pin Description IC power supply input. Bypass this pin to Ground pin with a capacitor. Ground pin. Enable pin. Pull it low to shutdown or pull it high to enable, do not leave floating. Output voltage adjust pin. Feedback the output voltage through resistor voltage divider network. Vo=0.6×(1+R1/R2) Output pin. Bypass this pin to Ground pin with a low ESR ceramic capacitor. Function Block AN_SY6345 Rev. 0.9 Silergy Corp. Confidential- Prepared for Customer Use Only 2 AN_SY6345 Absolute Maximum Ratings (Note 1) IN to GND ------------------------------------------------------------------------------------------------------ -0.3V to 40V OUT, EN, ADJ to GND -------------------------------------------------------------------------------- -0.3V to 0.3V+Vin Power Dissipation, PD @ TA = 25°C SOT23-5 ---------------------------------------------------------------------- 0.6W Package Thermal Resistance θJA ------------------------------------------------------------------------------------------------------------------170°C/W θJC ------------------------------------------------------------------------------------------------------------------130°C/W Storage Temperature --------------------------------------------------------------------------------------- -65C to +150°C Junction Temperature (TJ) ------------------------------------------------------------------------------------------- +150°C Lead Temperature (Soldering, 10sec.) ------------------------------------------------------------------------------+260°C Recommended Operating Conditions Supply Input Voltage ---------------------------------------------------------------------------------------------- 4V to 40V Junction Temperature (TJ) ------------------------------------------------------------------------------- -40°C to +125°C Ambient Temperature Range --------------------------------------------------------------------------------- -40°C to 85°C AN_SY6345 Rev. 0.9 Silergy Corp. Confidential- Prepared for Customer Use Only 3 AN_SY6345 Electrical Characteristics (VIN =12V,VEN=VIN, TA = 25°C unless otherwise specified) Parameter Symbol Test Conditions Input Voltage VIN IOUT=10mA Reference Voltage VREF Line Regulation ∆VLNR Load Regulation ∆VLDR VIN=12V, Io=10mA VIN=(VOUT+0.3V) to 40V, IO=10mA IO=10mA to 300mA Dropout Voltage VIN-VOUT Min Typical Max 40 V 600 612 mV 4 588 1 Unit mV/V 0.25 1 % IO=10mA 10 mV IO=150mA 150 mV IO=300mA 300 mV Quiescent Current IQ No Load 7 10 µA Shutdown Current ISHDN VEN=0V, VIN=24V Output Current IO VIN=VOUT+0.6V Output Current limit ILIM VIN= 6V,VOUT=0.9xVOUT(normal) Power-supply Rejection Ratio PSRR Input UVLO Threshold VUVLO UVLO Hysteresis VUVLO_th 0.2 V Shutdown Discharge Resistance RDIS 600 Ω Enable Input Logic-High Voltage VEN_H V IN =5V to 40V Enable Input Logic-Low Voltage VEN_L V IN =5V to 40V Thermal Shutdown Temperature TSD 150 °C Thermal Shutdown hysteresis THYS 20 °C 1.25 µA 0 300 mA 350 750 mA f=1kHz, COUT=10uF 60 f=150kHz, COUT=10uF 30 V IN rising dB dB 3.8 V 1.5 V 0.4 V Note 1: Stresses beyond the “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Note 2: θJA is measured in the natural convection at TA = 25°C on a low effective two-layer thermal conductivity test board of JEDEC 51-3 thermal measurement standard. Note 3: The device is not guaranteed to function outside its operating conditions AN_SY6345 Rev. 0.9 Silergy Corp. Confidential- Prepared for Customer Use Only 4 AN_SY6345 Output Voltage (V) Output Voltage (V) Output Voltage (V) Dropout Voltage (mV) Typical Performance Characteristics Load Transient Load Transient (VIN=7.4V, VOUT=5V, IOUT=0~150mA) (VIN=7.4V, VOUT=5V, IOUT=30~300mA) ∆VOUT IO 50mV/div 100mA/div Time (100µs/div) AN_SY6345 Rev. 0.9 ∆VOUT IO 50mV/div 200mA/div Time (100µs/div) Silergy Corp. Confidential- Prepared for Customer Use Only 5 AN_SY6345 Startup from VIN Shutdown from VIN (VIN=7.4V, VOUT=5V, IOUT=300mA) (VIN=7.4V, VOUT=5V, IOUT=300mA) VIN 5V/div VOUT 5V/div VIN 5V/div VOUT 5V/div IO IO 0.2A/div 0.2A/div Time (2ms/div) VEN VOUT Time (2ms/div) Startup from Enable Shutdown from Enable (VIN=7.4V, VOUT=5V, IOUT=300mA) (VIN=7.4V, VOUT=5V, IOUT=300mA) VEN 5V/div VOUT 5V/div 5V/div 5V/div IO IO 0.2A/div 0.2A/div Time (800µs/div) AN_SY6345 Rev. 0.9 Time (100µs/div) Silergy Corp. Confidential- Prepared for Customer Use Only 6 AN_SY6345 Application information The SY6345 is a 300mA linear regulator with a low drop out voltage. Like any low-dropout regulator, SY6345 requires input and output decoupling capacitors. Feedback resistor dividers R1 and R2: Choose R1 and R2 to program the proper output voltage. To minimize the power consumption under light loads, it is desirable to choose large resistance values for both R1 and R2. A value of between 10kΩ and 1MΩ is highly recommended for both resistors. If VOUT is 3.3V, R1=100k is chosen, then using following equation, R2 can be calculated to be 22.1k: VOUT 0.6V R2 = R1 . VOUT − 0.6V 0.6VADJ GND R1 R2 Input capacitor CIN: An input capacitor about 2.2uF is required between the device input pin and ground pin. A typical X5R or better grade ceramic capacitor is recommended in this application. This input capacitor must be located close to the device to minimize the input noise. Output capacitor COUT: For transient stability, SY6345 is designed specifically to work with very small ceramic output capacitors. 2.2uF output capacitance can be used in this application. Higher capacitance values help to improve transient. The output capacitor’s ESR is critical because it forms a zero to provide phase lead which is required for loop stability. condition, the power loss of the IC is relative high. And that may trigger the thermal protection. Thermal Considerations: The SY6345 can deliver a current of up to 300mA over the full operating junction temperature range. However, the maximum output current must be derated at higher ambient temperature to ensure the junction temperature does not exceed 125℃. With all possible conditions, the junction temperature must be within the range specified under operating conditions. Power dissipation can be calculated based on the output current and the voltage drop across regulator. PD=(VIN－VOUT)×IOUT+VIN×IGND The final operating junction temperature for any set of condition can be estimated by the following thermal equation: PD(MAX)=(TJ(MAX)－TA)/θJA Where TJ(MAX) is the maximum junction temperature of die (125℃) and TA is the maximum ambient temperature. The junction to ambient thermal resistance (θJA) footprint is 170℃/W for SOT23-5 package. Load Transient Considerations: The SY6345 regulator IC integrates the compensation components to achieve good stability and fast transient responses. In some applications, adding a small ceramic cap in parallel with R1 may further speed up the load transient responses and is thus recommended for applications with large load transient step requirements. Dropout Voltage: SY6345 has a very low dropout voltage due to its extra low RDS(ON) of the main PMOS determines the lowest usable supply . VDROPOUT=VIN－VOUT=RDS(ON)×IOUT Over Current and Short Circuit Protection: The device includes over current and short circuit protection. The current limitation circuit regulates the output current to its limitation threshold to protect IC from damage. Under over current or short circuit AN_SY6345 Rev. 0.9 Layout Design: Good board layout practices must be used or instability can be induced because of ground loops and voltage drops, and large PCB copper area can Silergy Corp. Confidential- Prepared for Customer Use Only 7 AN_SY6345 improve the thermal performance. The input and output capacitors MUST be directly connected to the input, output, and ground pins of the device using traces which have no other currents flowing through them. The best way to do this is to layout CIN and COUT near the device with short traces to the VIN, VOUT, and ground pins. The regulator ground pin should be connected to the external circuit ground so that the regulator and its capacitors have a “single point ground”. Below is the recommended PCB layout diagram: AN_SY6345 Rev. 0.9 Silergy Corp. Confidential- Prepared for Customer Use Only 8 AN_SY6345 SOT23-5 Package outline & PCB layout design 0.55 1.50 - 1.70 0.80 2.70 - 3.00 2.40 2.80 - 3.10 0.95 TYP 0.30 - 0.50 0.01 - 0.1 0.1 - 0.15 0.25 REF Recommended Pad Layout 1.0 - 1.3 0.95 TYP 0.3 - 0.6 1.90 TYP Notes: All dimensions are in millimeters. All dimensions don’t include mold flash & metal burr. AN_SY6345 Rev. 0.9 Silergy Corp. Confidential- Prepared for Customer Use Only 9 AN_SY6345 Taping & Reel Specification 1. Taping orientation SOT23-5 3.9/4.1 7.7/8.3 1.45/1.55 Feeding direction 2. Carrier Tape & Reel specification for packages Reel Size Package types Tape width (mm) Pocket pitch(mm) Reel size (Inch) Trailer length(mm) Leader length (mm) Qty per reel SOT23-5 8 4 7" 280 160 3000 3. Others: NA AN_SY6345 Rev. 0.9 Silergy Corp. Confidential- Prepared for Customer Use Only 10