SY6874DBC

Application Notes: AN_SY6874 Programmable Current Limit Switch General Description Features SY6874 is a programmable current limit switch with input voltage range selection and output voltage clamping. Extremely low RDS(ON) of the integrated protection N-channel FET helps to reduce power loss during the normal operation. Programmable soft-start time controls the slew rate of the output voltage during the start-up time. Independent enable control allows the complicated system sequencing control. It integrates the over-temperature protection shutdown and autorecovery with hystersis. This IC along with small DFN3X3-10 footprint provides small PCB area application.. • Wide Input Voltage Range from 2.5V to 15V with surge up to 30V • Extremely Low RDS(ON) for the Integrated Protection Switch: 50 mΩ • Programmable Soft-Start Time • Programmable Current Limit up to 4A • Short-circuit Protection • Selectable Input Range and Clamping Output Voltage Threshold. • Enable Interface Pin • Thermal Shutdown Protection & Auto Recovery • RoHS Compliant and Halogen Free • Compact package: DFN3X3-10 Ordering Information Applications SY6874 □(□□)□ Temperature Code Package Code Optional Spec Code Ordering Number SY6874DBC Package type DFN3x3-10 Note ---- • • • • Notebook PC I-pad Mini Server Service PC Typical Applications Figure 1. Schematic Diagram AN_SY6874 Rev. 0.9A Silergy Corp. Confidential- Prepared for Customer Use Only 1 AN_SY6874 Pinout (top view) (DFN3x3-10) Top mark: JTxyz for SY6874 (Device code: JT, x=year code, y=week code, z= lot number code) Pin Name Pin Number Pin Description IN 1,2,3 GND 11(exposed paddle) OUT ILIM 8,9,10 5 SST 6 EN VCP 7 4 Power input pin. Decouple high frequency noise by connecting at least 0.1uF MLCC to ground. Ground pin. Power output pin. Current limit program pin. Program the current limit by connecting a resister to ground. Soft-start time program pin. Connect a capacitor to ground to program the soft start time. Enable interface pin. Pull it High to enable the IC. Output clamp voltage selection based on the input voltage. Pull VCP pin to High by connecting a resistor to IN, or pull VCP pin to Low by connecting a resistor to ground, or float VCP Pin to select different output clamping thresholds. Recommend to decoupling this pin with 0.1uF capacitor. Clamping Threshold VCP IN Min Typ Max Low 3.3V Over 4V 3.6V 3.8V 4.0V High 5V Over 6V 5.4V 5.7V 6.0V Open 12V Over 14V 12.6V 13.3V 14V Block Diagram AN_SY6874 Rev. 0.9A Silergy Corp. Confidential- Prepared for Customer Use Only 2 AN_SY6874 Absolute Maximum Ratings (Note 1) Supply Input Voltage ----------------------------------------------------------------------------------------- 30V EN pin, VCP pin, ---------------------------------------------------------------------------------------------- 30V Power Dissipation, PD @ TA = 25°C DFN3X3-10, ------------------------------------------------------- 2.6W Package Thermal Resistance (Note 2) θ JA ------------------------------------------------------------------------------------------------------------- 38°C/W θ JC ------------------------------------------------------------------------------------------------------------- 8°C/W Junction Temperature Range -------------------------------------------------------------------------------- 125°C Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------- 260°C Storage Temperature Range ---------------------------------------------------------------------------------- -65°C to 150°C Recommended Operating Conditions (Note 3) Supply Input Voltage ----------------------------------------------------------------------------------------- 2.5V to 15V Junction Temperature Range -------------------------------------------------------------------------------- -40°C to 125°C Ambient Temperature Range ------------------------------------------------------------------------------- -40°C to 85°C Electrical Characteristics (VIN = 5V, RLIM=10kΩ, CSST=105nF, CIN = 10uF, COUT = 10uF, TA = 25°C, unless otherwise specified ) Parameter Input Voltage Range Input UVLO Threshold Symbol VIN VUVLO UVLO hysteresis VHYS Bias Current Shutdown Current Protection FET RON Current Limit Accuracy Current Limit Program Range Clamping Output Voltage Soft-start Time Soft-start Time Accuaracy EN Turn-on Threshold EN Turn-off Threshold Thermal Shutdown Temperature Thermal Shutdown Hysteresis IBIAS ISHDN RDS(ON) ILIM VCLP TSST VEN_ON VEN_OFF TSD THYS Test Conditions VCP=LOW VCP=HIGH VCP=OPEN VCP=LOW VCP=HIGH VCP=OPEN Min 2.5 2.2 3.4 8.1 0.05 0.06 0.1 EN=0 (Note 5) VCP=LOW VCP=HIGH VCP=OPEN 1 3.6 5.4 12.6 CSST=105nF(Note 4) Typ 0.085 0.095 0.19 200 10 50 30%ILIM 3.8 5.7 13.3 29.4 ±30%TSST Max 30 2.4 3.8 9.0 0.13 0.15 0.29 80 4 4.0 6.0 14.0 2 Unit V V V V V µA µA mΩ A V V V ms 140 V V °C 20 °C 0.4 Note 1: Stresses beyond the “Absolute Maximum Ratings” may cause permanent damage to the device. These are for stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect device reliability. AN_SY6874 Rev. 0.9A Silergy Corp. Confidential- Prepared for Customer Use Only 3 AN_SY6874 Note 2: θ JA is measured in the natural convection at TA = 25°C on a low effective single layer thermal conductivity test board of JEDEC 51-3 thermal measurement standard. Test condition: Device mounted on 2” x 2” FR-4 substrate PCB, 2oz copper, with minimum recommended pad on top layer and thermal vias to bottom layer ground plane. Note 3. The device is not guaranteed to function outside its operating conditions Note4. Recommended Soft-start Time Program Table SST cap (nF) Rise time (ms) None 1.4 10 2.8 55 15.4 105 29.4 Recommended Formula for CSST & Soft-start Time Calculation TSS _ DLT , No external CSST  , TSS =  C SST , TSS > TSS_DLT  I INT Where, TSS_DLT is the internally fixed default soft-start time, about 1.4ms, which means there’s no any external CSST; IINT is the internal current source, about 3.6uA. Note5. Recommended Current Limit Program Table Current Limit Resistance (kΩ) Current Limit (A) 11 1.0 5.5 2.0 4.4 2.5 3.7 3.0 3.1 3.5 2.8 4.0 Recommended Formula for RLIM & Current Limit Calculation RLIM = 11k (Ω) . I LIM AN_SY6874 Rev. 0.9A Silergy Corp. Confidential- Prepared for Customer Use Only 4 AN_SY6874 Typical Performance Characteristics Programmable Soft-start Time ( 3.3V Mode, IO=1A, CSST=100nF) ILIMIT(A) VVININ VVOUT OUT IOIO 2.0V/div 2.0V/div 1.0V/div 2.0V/div 500mA/div 0.5A/div Time (10ms/div) AN_SY6874 Rev. 0.9A Silergy Corp. Confidential- Prepared for Customer Use Only 5 AN_SY6874 VIN VIN VV OUT OUT IO IO Shutdown Over Voltage Protection ( 12V Mode, IO=1A, CSST=100nF) ( 5V Mode, VIN=8V, IO=0A) 5.0V/div 5.0V/div VIN 5.0V/div 5.0V/div 5.0V/div 0.5A/div 500mA/div 2.0V/div VINVOUT2.0V/div Time (2.0ms/div) AN_SY6874 Rev. 0.9A VOUT 2.0V/div IOIO 0.5A/div 500mA/div Time (400ms/div) Silergy Corp. Confidential- Prepared for Customer Use Only 6 AN_SY6874 PCB Layout Guideline Top Silkscreen AN_SY6874 Rev. 0.9A Top Layer Bottom Layer Silergy Corp. Confidential- Prepared for Customer Use Only 7 AN_SY6874 DFN3x3-10 Package outline Top View PCB layout (recommended) Side View Detail A Pin1 identifier: two options Bottom View Notes: All dimensions are in millimeters and exclude mold flash & metal burr. AN_SY6874 Rev. 0.9A Silergy Corp. Confidential- Prepared for Customer Use Only 8 AN_SY6874 Taping & Reel Specification 3.9/4.1 1.45/1.55 11.7/12.3 1. DFN3x3-10 taping orientation Feeding direction 2. Carrier Tape & Reel specification for packages Reel Width Reel Size Package types DFN3x3 Tape width (mm) Pocket pitch(mm) Reel size (Inch) Reel width(mm) Trailer length(mm) Leader length (mm) Qty per reel 10 8 13" 12.4 400 400 5000 3. Others: NA AN_SY6874 Rev. 0.9A Silergy Corp. Confidential- Prepared for Customer Use Only 9