HSMC3842

H3842P HSMC | Alldatasheet

Document overview

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• PDF pages: 10

Technical content

Features

• Trimmed Oscillator for Precise Frequency Control
• Oscillator Frequency Guaranteed at 250 kHz
• Current Mode Operation to 500 kHz
• Automatic Feed Forward Compensation
• Latching PWM for Cycle-By-Cycle Current Limiting
• Internally Trimmed Reference with Undervoltage Lockout
• High Current Totem Pole Output
• Undervoltage Lockout with Hysteresis
• Low Startup and Operating Current Absolute Maximum Ratings Symbol Parameter Value Unit Vi Supply Voltage (low impedance source) 30 V Vi Supply Voltage (Ii<30mA) Self Limiting Io Output Current ±1 A Eo Output Energy (capacitive load) 5 uJ Analog Inputs (pin 2, 3) -0.3 to 5.5 V Error Amplifier Output Sink Current 10 mA Ptot Power Dissipation at Tamb≤25oC 1.25 W Tstg Storage Temperature Range -65 to 150 oC TJ Junction Operating Temperature -40 to 150 oC TL Lead Temperature (soldering 10s) 300 oC Block Diagram DIP-8Pin 34V R Vcc Ground VFB COMP Current Sense Error AMP. VREF Good Logic 2.50V Current Sense Comparator T UVLO REF Internal Bias PWM Latch Output VREF 5V 50mAS/R RT/CT S R OSC

MICROELECTRONICS CORP. Spec. No. : HP200202 Issued Date : 1998.08.01 Revised Date : 2002.12.03 Page No. : 2/10 H3842P HSMC Product Specification Pin Connection (Top View) DIP-8P Function Description Pin1: Compensation This pin is the Error Amplifier output and is made available for loop compensation. Pin2: Voltage Feedback This is the inverting input of the Error Amplifier. It’s normally connected to the switching power supply output through a resistor divider. Pin3: Current Sense A voltage proportional to inductor current is connected to this input. The PWM uses this information to terminate the output switch conduction. Pin4: RT/CT The oscillator frequency and maximum output duty cycle are programmed by connecting resistor RT to Vref and cpacitor CT to ground. Operation to 500kHz is possible. Pin5: Ground This pin is the combined control circuitry and power ground. Pin6: Output This output directly drives the gate of a power MOSFET. Peak currents up to 1A are sourced and sunk by this pin. Pin7: Vcc This pin is the positive supply of the control IC. 12 34 5678 Pin8: Vref This is the reference output. It provides charging current for capacitor CT through resistor RT. Thermal Data Symbol Description Max. Units Rth j-amb Thermal Resistance Junction-ambient 100 oC/W Electrical Specifications Parameter Test Conditions Min. Typ. Max. Units Under-Voltage Lockout Section Start Threshold 14.5 16 17.5 V Min. Operating Voltage After Turn On 8.5 10 11.5 V

Electrical Characteristics

Unless otherwise stated, specifications apply for 0≤Ta≤70°C Vcc =15V (Note 1); RT=680Ω , CT=0.022uF for triangular mode, RT=10k, CT=3.3nf for sawtooth mode Parameter Test Conditions Min. Typ. Max. Units Reference Section Reference Output Voltage Tj=25°C,Io=1mA 4.90 5 5.1 V Line Regulation 12V≤Vin≤25V -2 . 0 2 0 m V Load Regulation 1mA≤Io≤20mA -3 . 0 2 5 m V Temperature. Stability (Note 2) -0 . 2- mV/°C Total Output Variation Line , Load , Temp (Note 2) 4.82 - 5.18 V Output Noise Voltage 10Hz≤f≤10kHz,Tj=25°C (Note 2) -5 0- u V Long Term Stability Ta=125°C,1000Hrs (Note 2) -5- m V Output Short current Ta=25°C -30 -100 -180 mA Oscillator Section Tj=25°C 47 52 57 KHzFrequency Tlow≤Ta≤Thigh 46 52 60 KHz Frequency Chnge with Temperature 12V≤Vcc≤25V -0 . 21 % Tlow≤Ta≤Thigh (Note 2) -5-%Frequency Change with Temperature Tj=25°C -0 . 5- % Oscillator Voltage Swing Peak to Peak - 1.7 - V

MICROELECTRONICS CORP. Spec. No. : HP200202 Issued Date : 1998.08.01 Revised Date : 2002.12.03 Page No. : 3/10 H3842P HSMC Product Specification Parameter Test Conditions Min. Typ. Max. Units Error Amplifier Section Voltage Feedback Input Vo=2.5V 2.42 2.50 2.58 V Input Bias Current VFB=5.0V - -0.1 -2.0 uA Open Loop Voltage Gain 2≤Vo≤4 V 65 90 - dB Unity Gain Bandwidth Tj=25°C (Note 2) 0.7 1.0 - MHz Power Supply Rejection Ratio 12V≤Vcc≤25V 60 70 - dB Output Voltage Swing High State VFB=2.3V, RL=15K to ground 5 6 - V Low State VFB=2.7V, RL=15K to Vref - 0.7 1.1 V Current Sense Section Current Sense Input Voltage Gain (Notes 3 & 4) 2.85 3.0 3.15 V/V Maximum Current Sense Input Thresold (Note 3) 0.9 1.0 1.1 V Ppwer Supply Rejection Ratio 12V≤Vcc≤25V (Note 3) -7 0- d B Input Bias Current - -2.0 -10 uA Propagation Delay Tj=25°C (Note 2) - 150 300 nS Output Section Low State (Isink=20mA) - 0.1 0.4 V Low State (Isink=200mA) - 1.5 2.2 V High State (Isource=20mA) 13 13.5 - VOutput Voltage High State (Isource=200mA) 12 13.4 - V Output Voltage Rise Time Tj=25°C, CL=1.0nF (Note 2) - 50 150 nS Output Voltage Fall Time Tj=25°C, CL=1.0nF (Note 2) - 50 150 nS Output Voltage with UVLO Activated Vcc=6V , Isink=1.0mA - -0.1 -1.1 V Total Device Start-Up Current - 0.1 0.5 mA Operating Supply Current Vpin2=Vpin3=0, RT=10K, CT=3.3nF - 11 17 mA Vcc Zener Voltage Icc=25 mA - 34 - V Note 1: Adjust Vcc above the start threshold before setting at 15V. Note 2: These parameters, although guaranteed are not 100% tested in production. Note 3: Parameter measured at trip point of latch with Vpin2=0. Note 4: Gain defined as: A=Vpin1/Vpin3, 0≤Vpin3≤0.8V

MICROELECTRONICS CORP. Spec. No. : HP200202 Issued Date : 1998.08.01 Revised Date : 2002.12.03 Page No. : 4/10 H3842P HSMC Product Specification Characteristics Curve Oscillator Frequency & Timing Resistance 10K 100K 1000K 10000K 100 1000 10000 100000 RT(Ω) fo(Hz) CT=1.0nF CT=2.2nF CT=4.7nF Maximum Duty Cycle & Timing Resistance 100 100 1000 10000 100000 RT(Ω) fo(Hz) Current Sense Input Threshold & Error Amp Output Voltage 0.2 0.4 0.6 0.8 1.2 02468 Vo (V) Vth (V) Ta=125oC Ta=-40oC Ta=25oC Vcc=15V Reference Voltage Change & Source Current 0 20 40 60 80 100 120 Iref (mA) Ta=125oC Ta=25oC Ta=-40oC Vcc=15V Oscillator Discharge Current & Temperate 7.5 8.5 -50 -25 0 25 50 75 100 125 TA (oC) Idischg (mA) Vi=15V Vosc=2V Error Amp Open-Loop Gain and Phase & Frequency -20 100 10 100 1000 10000 100000 1000000 10000000 f (Hz) (dB) Gain Phase Vcc=15V Vo=2V to 4V RL=100K Ta=25oC Φ 120 150 180

MICROELECTRONICS CORP. Spec. No. : HP200202 Issued Date : 1998.08.01 Revised Date : 2002.12.03 Page No. : 5/10 H3842P HSMC Product Specification Reference Short Circuit Current &Temperature 100 110 -50 -25 0 25 50 75 100 125 TA (oC) Isc (mA) Vcc=15V RL≤0.1Ω Supply Current & Supply Voltage 0 1 02 03 04 0 Vi (V) Ii (mA) RT=10K CT=3.3nF Output Saturation Voltage & Load Current 0 200 400 600 800 Io (mA) Vsat (V) Sink Saturation (Load to Vcc) Ta=-40oC Ta=25oC Vcc=15V 80us Pulsed Load 120Hz Rate Output Saturation Voltage & Load Current 0 200 400 600 800 Io (mA) Vsat (V) Source Saturation (Load to Ground) Ta=25oC Ta=-40oC Vcc=15V 80us Pulsed Load 120Hz Rate

MICROELECTRONICS CORP. Spec. No. : HP200202 Issued Date : 1998.08.01 Revised Date : 2002.12.03 Page No. : 6/10 H3842P HSMC Product Specification

Application Information

Oscillator and Output Waveforms Error Amp Configuration Under Voltage Lockout RT CT 8 5V REG PWM Clock Oscillator Id Output GND CT Output Large RT / Small CT CT Output Small RT / Large CT Vcc 4.7KΩ 1KΩ 4.7KΩ 5KΩ 100KΩ RT 0.1uF 0.1uF CT 1KΩ Error Amp. Adjust I Adjust HPN2222A COMP RT/CT V Vcc Output Ground Ground Output Vcc Vref 4 5 REF SENSE ISENSE VFB A H3842 High peak currents associated with capacitive loads necessitate careful grounding techniques. Timing and bypass capacitors should be connected close to pin5 in a single point ground. The transistor and 5K Ω potentiometerare used to samplethe oscillator waveform and apply an adjustable ramp to pin3. Zi Zf V COMP 2.5V 1mA 2FB ON/OFF Command Von Voff H3842 To Rest Of IC 16V 10V Icc <17mA <0.5mA Vcc Voff Von Vi 7

MICROELECTRONICS CORP. Spec. No. : HP200202 Issued Date : 1998.08.01 Revised Date : 2002.12.03 Page No. : 7/10 H3842P HSMC Product Specification Current Sense Circuit Slope Compensation Techniques Isolated MOSFET Drive and Current Transformer Sensing Peak current (Is) is determined by the formula Is(max.) ≈ 1V/Rs A small RC filter may be required to suppress switch transients. R Rs C COMPIs Current Sense GND Error Ampl. R1 V Current Sense Comparator Rs R RT CT SLOPE H3842 Is VREG RT/CT ISENSE GND Rs R RT CT SLOPE H3842 Is VREG RT/CT ISENSE GND 5.0Vref + Vcc S R Q COMP/Latch C R Rs Ns Np Vin Isolation Boundary VGS Waveforms 50%DC 25%DC Ipk=((Vpin1-1.4)/3Rs)(Ns/Np)

MICROELECTRONICS CORP. Spec. No. : HP200202 Issued Date : 1998.08.01 Revised Date : 2002.12.03 Page No. : 8/10 H3842P HSMC Product Specification 2N3903 2N3905 R OSC BIAS 1mA EA1 R R Latched Shutdown Error Amplifier Compensation External Clock Synchronization Ri Rd RfCf R 2.5V EA 1mA From Vo Rp RfCf R 2.5V EA 1mA From Vo RdRiCp SCR must be selected for a holding current of less than 0.5mA at TA(min). The simple two transistor circuit can be used in place of the SCR as shown. All resistors are 10K. Error Amp compensation circuit for stabilizing any current-mode topology except for boost and flyback converters operating with continuous inductor current Error Amp compensation circuit for stabilizing current-mode boost and flyback topologies operating with continuous inductor current. The diode clamp is required if the Sync amplitude is large enough to cause the bottom side of CT to go more than 300mV below ground 0.01uF CT RT 47Ω R R R EA OSC BIAS Vref External Sync Input

MICROELECTRONICS CORP. Spec. No. : HP200202 Issued Date : 1998.08.01 Revised Date : 2002.12.03 Page No. : 9/10 H3842P HSMC Product Specification Rs Vclamp Comp/Latch BC109 Vcc Vin 5Vref C R EA 1mA R R OSC BIAS S R Q +1V External Duty Cycle Clamp and Multi Unit Synchronization Soft-Start Circuit Soft-Start and Error Amplifier Output Duty Cycle Clamp 1MΩ 5Vref C R EA 1mA R R OSC BIAS S R Q -1V R R R EA OSC BIAS RA RB 5KΩ 5KΩ 5KΩC R S Q Vref NE555 To Additional H3842 - + f=1.44/((RA+2RB)C), Dmax=RB/(RA+2RB) Vclamp=R1/(R1+R2) where 0<Vclamp<1V, Ipk(max)=Vclamp/RS

MICROELECTRONICS CORP. Spec. No. : HP200202 Issued Date : 1998.08.01 Revised Date : 2002.12.03 Page No. : 10/10 H3842P HSMC Product Specification DIP-8P Dimension *: Typical G 0.1250 0.1400 3.17 3.55 α 19 4 ° 97° 94° 97° Notes: 1.Dimension and tolerance based on our Spec. dated Sep. 07,1997. 2.Controlling dimension: millimeters. 3.Maximum lead thickness includes lead finish thickness, and minimum lead thickness is the minimum thickness of base material. 4.If there is any question with packing specification or packing method, please contact your local HSMC sales office. Material:

• Lead: 42 Alloy; solder plating
• Mold Compound: Epoxy resin family, flammability solid burning class: UL94V-0 Important Notice:
• All rights are reserved. Reproduction in whole or in part is prohibited without the prior written approval of HSMC.
• HSMC reserves the right to make changes to its products without notice.
• HSMC semiconductor products are not warranted to be suitable for use in Life-Support Applications, or systems.
• HSMC assumes no liability for any consequence of customer product design, infringement of patents, or application assistance. Head Office And Factory: Tel: 886-2-25212056 Fax: 886-2-25632712, 25368454 Tel: 886-3-5983621~5 Fax: 886-3-5982931 DIP-8P Plastic Package Marking: Date Code PH 3842A B 87 65 4321 HI F G J K M L α1E D C