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AN7554

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  ©2003 Fairchild Semiconductor Corporation www.fairchildsemi.com Rev. 1.0.3 Features ãCurrent mode controlãPulse by pulse current limitingãLow external components ãUnder voltage lockout(UVLO): 9V/15VãStand-by current: typ. 100uAãPower saving mode current: typ. 200uAãOperating current: typ. 7mAãSoft start ãOn/off controlãOver load protection(OLP)ãOver voltage protection(OVP)ãOver current protection(OCP)ãOver current limit(OCL)ãOperating frequency up to 500kHzã1A totem-pole output current Applications ãOff-Line & DC-DC converter  Description The FAN7554 is a fixed frequency current mode PWM controller. It is specially designed for off-line and DC to DCconverter applications with minimal external components.These integrated circuits feature a trimmed oscillator for  precise duty cycle control, a temperature compensated reference, an ON/OFF control, a high gain error amplifier, acurrent sensing comparator, and a high current totem-poleoutput. The FAN7554 has various protection functions suchas an over load protection, an over current protection, andthe over voltage protection, which include built-in autorestart circuit. The FAN7554 is available in the 8-DIP  package as well as the 8-SOP package. FAN7554 Versatile PWM Controller  8-DIP8-SOP 11  FAN7554 2 Internal Block DiagramAbsolute Maximum Ratings ( Ta = 25 ° C, unless otherwise specified ) Note:1. Junction -to -air thermal resistance test environments.- JESD51-2 : Integrated circuits thermal test method environmental conditions-natural convection (still air).- JESD51-3 : Low effective thermal conductivity test board for leaded surface mount packages.- JESD51-10 : Test boards for through-hole perimeter leaded package thermal measurements. ParameterSymbolValueUnit Supply voltageVcc30VOutput currentI O ±1AInput voltage to FB pinV FB -0.3 to V SD VInput voltage to IS pinV IS -0.3 to V OC VPower dissipation at T  A   ≤  25 ° C8-DIP8-SOPP D 0.850.42WOperating temperatureT OPR -25 to +85 ° CStorage temperatureT STG -55 to +150 ° CThermal resistance, junction-to-air (Note1)8-DIP8-SOPR θ  ja147.8291.4 ° C/W OSC 6715438FBRt/CtVccOUTGNDI S2S/S 1.5V      + 3.5V0.3V14V15V/9VUVLO2VOLP6V5uAVccOffset(0.1V)PWM R MAX. 1V2R  UVLO-outSQR CLK PWR /SAVEonoff Vref SQR 1k Vref 100uAVref 1mA Vref  S R QOVP34VOVP-outOCL-outOCL    _      +    _      +    _      +    _      +    _      +    _      +    _      +    _ OSC   6   67   71   15   54   43   38   8FBRt/CtVccOUTGNDI S2   2S/S 1.5V      + 3.5V0.3V14V15V/9VUVLO2VOLP6V5uAVcc5uAVccOffset(0.1V)PWM R MAX. 1V2R  UVLO-outSQR CLK PWR /SAVEonoff Vref SQR 1k 1k Vref 100uAVref 1mA Vref  S R QOVP34VOVP-outOCL-outOCL    _      +    _      +    _      +    _      +    _      +    _      +    _      +    _  FAN7554 3 Temperature Characteristics ( -25 ° C   ≤   Ta   ≤  85 ° C ) PIN ArrayPIN Definitions ParameterSymbolValueUnit Vref temperature stability ∆ V REF 3±0.5%Fosc temperature stability ∆ F OSC 2±5% Pin NumberPin NamePin Function Description 1FBInverting(-) input of pwm comparator, on/off control & OLP sensing terminal.2S/SSoft start3ISNon-inverting(+) input of PWM comparator, OCL sensing terminal4Rt/CtOscillator time constant(Rt/Ct)5GNDGround6OUTOutput of gate driver 7VccPower supply8VrefOutput of 5V reference Vref VccOUTGND 7777 6666 555588882222 3333 44441111 YYYYW   WW   WAAAAN   N7777555555554444F FF F  Rt/CtISS/SFB  FAN7554 4 Electrical Characteristics (Ta = 25 ° C, Vcc=16V, Rt=10k Ω , Ct=3.3nF unless otherwise specified) ParameterSymbolConditionsMin.Typ.Max.Unit< REFERENCE SECTION > Reference output voltageV REF T  j  =25 ° C , Iref =1mA4.905.005.10VLine regulation ∆ V REF1 Vcc =12V ~ 25V-620mVLoad regulation ∆ V REF2 Iref =1mA ~ 20mA-625mVShort circuit output currentI SC T  j = 25 ° C-0.10.18A < OSCILLATOR SECTION > Oscillation frequencyF OSC T  j  = 25 ° C455055kHzFrequency change with Vcc ∆ F OSC1 Vcc = 12V ~ 25V-0.051.0%Ramp high voltageV RH --2.8-VRamp low voltageV RL --1.2-VDischarge currentIdischV RT/CT  = 3.3V6.1-9.4mA < PWM SECTION > Sense threshold voltageV TH(IS) V FB  = 5V0.81.01.2VFeedback threshold voltageV TH(FB) V IS  = 0V0.20.30.4VFeedback source currentI FB V FB  = 0V, V S/S  = 5V-1.0-mAMax. duty cycleD (MAX) -929598%Min. duty cycleD (MIN) ---0% < PROTECTION SECTION > Shutdown delay currentI SD 4V ≤  V FB   ≤  V SD 3.556.5uAShutdown feedback voltageV SD V FB  > 5V5.466.6VOver current protectionV OC V IS  > 1.5V,   t on  > 500nS 1.622.4VOver voltage protectionV OVP -303438V < ON/OFF CONTROL SECTION > Off mode sink currentI SINK V FB  < V TH(FB) , V S/S  = 5V-4-mAOff threshold voltageV OFF V FB  < V TH(FB) 1.21.51.8V < SOFT-START SECTION > Soft start currentI S/S V FB  = 5V, V S/S  = 0V-1.1-mASoft start limit voltageV LIM(S/S) Vcc = 16V-5.2-V <OUTPUT SECTION> Low output voltage1V OL1 V CC  = 18V, I O  = 50mA-0.150.4VHigh output voltage1V OH1 V CC  = 18V, I O  = -50mA131517VLow output voltage2V OL2 V CC  = 18V, I O  = 200mA-1.52.5VHigh output voltage2V OH2 Vcc = 18V, Io = -200mA121416VRising time (Note1)t R T  j = 25 ° C, C L  = 1nF-80-nsFalling time (Note1)t F T  j = 25 ° C, C L  = 1nF-40-ns <UVLO SECTION> Start threshold voltageV TH(ST) - 13.21516.2VMin. operating voltageV OPR(M) - 8.2910.2V

Zero Max Rohlix

Jul 23, 2017
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