Bay Linear Inspire the Linear Power B3842/43/44/45A&A1 Current Mode PWM Controller Description Features The Bay Linear B3842/43/44/45 are fixed frequency currentmode PWM controller. These devices are designed for OffLine and DC-to-DC converter applications with minimum external components. The B3842 family Feature a trimmed oscillator for precise duty cycle control, a temperature compensated reference, high gain error amplifier, current sensing comparator, and a high current totempole output. Ideally suited for driving a power N-Channel MOSFET’s. It is low when is on off stage. Protection circuitry includes built in under-voltage lockout and current limiting. Major differences between members of these series are the UVLO thresholds and maximum duty-cycle ranges. Typical UVLO thresholds of 16V (on) and 10V (off) on the B3842 and B3844 devices make them ideally suited to off-line applications. These corresponding typical thresholds for the B3842 and B3845 devcies are 8.4V (on) and 7.6V (off). The B3842 and B3843 devcies can operate to duty cycles approaching 100%. A duty-Cycle range of 0 to 50% is obtained by the B3844 and B3845 by the addition of an internal toggle flip-flop, which blanks the output off every other clock cycle. It id available in 8 pin DIP and SOIC packages. Pin Connection • • • • • • Low Start-Up and Operating Current Maximum Duty Cycle Operating Frequency Up to 500KHz Under voltage Lockout with Hysteresis Available in 8 pin SOIC Similar to industry Standard UC3842 Applications • • Switching Power Supply Monitor Ordering Information Devices B384X(Z)M B384X(Z)P Z=A ON Semi Package Temp. SO-8 0 °C to 70 °C 8-DIP 0 °C to 70 °C Z=A1 Fairchild & Samsung 8-Pin Surface Mount COMP 1 8 REF NC 2 7 VCC ISENSE 3 6 OUTPUT 4 5 GND RT/CT Top View Bay Linear, Inc 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com B384X Absolute Maximum Rating Parameter Supply Voltage Output Current Analog Input (pin 2,3) Error Amp Output Sink Current Power Dissipation Storage Temperature Range Lead Temperature (Soldering 10 Sec.) Symbol Value Unit VCC IO V(ANA) 30 ±1 -0.3 to 6.3 10 1 -65 to 150 260 V A V mA W °C °C ISINK (E.A) PD T TL Electrical Characteristics (VCC = 15V;RT = 10Ω, CT = 3.3nF, TA=0 °C to +70°C, unless otherwise specified) Parameter Symbol Conditions MIN REFERENCE SECTION Reference Voltage Line Regulation Load Regulation VREF REG (line) REG (LOAD) Short Circuit Output Current ISC OSCILLATOR SECTION Oscillator Frequency f Frequency Change with ∆f/∆VCC Voltage Oscillator Amplitude VOSC ERROR AMPLIFIER SECTION Input Bias Current IBIAS Input Voltage VI(E>A) Open Loop Voltage Gain GVO Power Supply Rejection PSRR Ratio Output Sink Current ISINK Output Source Current ISOURCE High Output Voltage VOH Low Output Voltage VOL OUTPUT SECTION Low Output Voltage VOL High Output Voltage Rise Time Fall Time VOH tR tF TYP MAX UNIT 4.90 5.00 5.10 V 12V≤VCC≤25V - 6 20 mA 1mA≤IREF≤20mA T= 25 °C - 6 25 T= 25 °C - -100 -180 mA 47 - 52 0.05 57 1 KHz % - 1.6 - VP-P V1 =2.5V 2V≤VO≤4V 12V≤VCC≤25V 2.42 65 60 -0.1 2.50 90 70 -2 2.58 - µA V dB dB V2 =2.7V, V1 =1.1V V2=2.3, V1=5V V2=2.3, RL= 15Ω to GND V2=2.7, RL= 15Ω to pin 8 2 -0.6 5 - 7 -1.0 6 0.8 1.1 mA mA V V ISINK = 20mA ISINK = 200mA Source = 20mA Source = 200mA TJ = 25 °C, CL=1nF (note3) TJ = 25 °C, CL=1nF (note3) - 0.08 1.4 13.5 13.0 45 35 0.4 2.2 150 150 V TJ = 25 °C. IREF= 1mA T= 25 °C 12V≤VCC≤25V 13 12 - V ns ns Note: Output Switch tests are performed under pulsed conditions to minimize power dissipation Bay Linear, Inc 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com B384X Electrical Characteristics (VCC = 15V;RT = 10Ω, CT = 3.3nF, TA=0 °C to +70°C, unless otherwise specified) Parameter Symbol Conditions MIN CURRENT SENSE SECTION Gain GV (Note 1 & 2) Maximum input Signal VI(MAX) V1 = 5V (Note 1) Power Supply Rejection PSRR 12V≤VCC≤25V Ratio Input Bias Current IBIAS UNDER-VOLTAGE LOCKOUT SECTION B3842/B3844 Start Threshold VTH(ST) B3843/B3845 B3842/B3844 Min-Operating Voltage VOPR(MIN) (after Turn On) B3843/B3845 PWM SECTION B3842/B3843 Max Duty Cycle D(MAX) B3844/B3845 Min Duty Cycle D (MIN) TOTAL STANDBY CURRENT B3842A/43A/44A/45A Start-Up Current IST B3842A1/43A1/44A1/45A1 Operating Supply Current ICC(OPR) V3=V2=ON Zener Voltage VZ ICC TYP MAX UNIT 3 1 3.15 1.1 V/V V 70 - dB -3 -10 µA 14.5 7.8 8.5 7.0 16 8.4 10 7.6 17.5 9 11.5 8.2 95 47 - 97 48 - 100 50 0 - 0.17 0.45 14 38 0.3 1 17 - 2.85 0.9 30 V V % % mA mA V Block Diagram Bay Linear, Inc 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com B384X Figure 1: Error Amp Configuration Figure 2: Under-Voltage Lockout 3842 3843 Figure 3: Current Sense Circuit Bay Linear, Inc 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com B384X Bay Linear, Inc 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com B384X Figure 4: Slope Conpensation Techigues B3842A B3842A Figure 5:Latched Shutdown Bay Linear, Inc 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com B384X Bay Linear, Inc 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com B384X Bay Linear, Inc 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com B384X Bay Linear, Inc 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com Advance Information- These data sheets contain descriptions of products that are in development. The specifications are based on the engineering calculations, computer simulations and/ or initial prototype evaluation. Preliminary Information- These data sheets contain minimum and maximum specifications that are based on the initial device characterizations. These limits are subject to change upon the completion of the full characterization over the specified temperature and supply voltage ranges. The application circuit examples are only to explain the representative applications of the devices and are not intended to guarantee any circuit design or permit any industrial property right to other rights to execute. Bay Linear takes no responsibility for any problems related to any industrial property right resulting from the use of the contents shown in the data book. Typical parameters can and do vary in different applications. Customer’s technical experts must validate all operating parameters including “ Typical” for each customer application. LIFE SUPPORT AND NUCLEAR POLICY Bay Linear products are not authorized for and should not be used within life support systems which are intended for surgical implants into the body to support or sustain life, in aircraft, space equipment, submarine, or nuclear facility applications without the specific written consent of Bay Linear President. Bay Linear, Inc 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com