AMC3842B/43B/44B/45B CURRENT MODE PWM CONTROLLER www.addmtek.com DESCRIPTION FEATURES The AMC3842B/43B/44B/45B are fixed frequency current-mode PWM controllers specially designed for OFF-Line switching power supply and DC-to-DC converters with a minimum number of external components. These devices feature a trimmed oscillator for precise duty cycle control, a temperature compensated reference, high gain error amplifier, current sensing comparator, and high current totem pole output which is suitable for driving MOSFETs. The under voltage lock-out (U.V.L.O.) is designed to operated with 200µA start-up current in typical, allowing an efficient bootstrap supply voltage design. The U.V.L.O. thresholds for the AMC3842B/44B are 16V (on) and 10V (off), which are ideal for off-line applications. The corresponding typical threshold for the AMC3843/45BB is 8.4V (on) and 7.6V (off). The AMC3842B/43B can operate within 100% duty cycle and the AMC3844B/45B can operate within 50% duty cycle. APPLICATIONS Low Start-Up current (max. 200µA) Optimized for Off-Line and DC-to-DC Converters Maximum Duty Cycle U.V.L.O. with Hysteresis Operating Frequency Up to 500KHz Internal Trimmed Bandgap Reference High Current Totem Pole Output Error Amplifier With Low Output Resistance Available in 8-Pin Plastic DIP and Surface Mount 14-Pin S.O.I.C. Identical pin assignment to earlier UC384X series. PACKAGE PIN OUT VREF COMP Off-line flyback or forward converters. DC-to-DC buck or boost converter. Monitor Power Supply VFB VCC ISENSE OUTPUT RT/CT GND 8-Pin Plastic DIP (Top View) Start-UP Voltage Device Hysteresis Max. Duty Cycle AMC3842B 16V 6V < 100% AMC3843B 8.4V 0.8V < 100% AMC3844B 16V 6V < 50% AMC3845B 8.4V 0.8V < 50% TA (OC) 0 to 70 0 to 70 Note: VREF COMP AVAILABLE OPTIONS NC VFB NC VCC NC VC ISENSE VREF RT/CT GND OUTPUT NC GND RT/CT PWR 14-Pin Plastic S.O.I.C. Surface Mount (Top View) ORDER INFORMATION Plastic DIP-8 Plastic SO-14 M 8-pin D 14-pin AMC384XBM AMC384XBD AMC384XBM (Lead Free) AMC384XBD (Lead Free) 1. All surface-mount packages are available in Tape & Reel. AMC384XBDMT). 2. The letter ”F” is marked for Lead Free process. Copyright © 2006 ADDtek Corp. COMP VFB ISENSE 1 VCC OUTPUT 8-Pin Plastic S.O.I.C. Surface Mount (Top View) Plastic SO-8 DM 8-pin AMC384XBDM AMC384XBDM (Lead Free) Append the letter “T” to part number (i.e. AMC384XBDT, or DD019_F -- OCTOBER 2006 AMC3842B/43B/44B/45B ABSOLUTE MAXIMUM RATINGS (Note 1) 35V ± 1A -0.3V to 6.3V 10mA 1W 150 OC -65OC to 150OC 260 OC Supply voltage, VCC Output current, IO Analog inputs, VI Error amp output sink current, ISINK(EA) Power dissipation (TA = 25 OC), PD Maximum juncture temperature, TJ Storage temperature range Lead temperature (soldiering, 10 seconds) Note 1: Exceeding these ratings could cause damage to the device. negative out of the specified terminal. All voltages are with respect to Ground. Currents are positive into, THERMAL DATA M PACKAGE: Thermal Resistance-Junction to Ambient, θJA 95 OC/W D PACKAGE: Thermal Resistance-Junction to Ambient, θJA 120 OC/W DM PACKAGE: Thermal Resistance-Junction to Ambient, θJA 165 OC/W Junction Temperature Calculation: TJ = TA + (PD × θJA). The θJA numbers are guidelines for the thermal performance of the device/pc-board system. All of the above assume no ambient airflow. Copyright © 2006 ADDtek Corp. 2 DD019_F -- OCTOBER 2006 AMC3842B/43B/44B/45B BLOCK DIAGRAM 7 (12) Internal Bias VREF U.V.L.O. 36V 5V EN VREF 8 (14) 5 (9) GND VREF Good Logic Error Amp VFB 2R 1V R COMP 1 (1) RT/CT 7 (11) PWR VC Current Sense 2 (3) CURRENT SENSE VCC PWM Latch R OUTPUT 6 (10) S 3 (5) 4 (7) T PWR 5 (8) GND Oscillator ( ) are 14 Pin S.O.I.C. pin number Note 2: VCC and PWR VC are internally connected for 8 pin packages. Note 3: PWR GND and GND are internally connected for 8 pin packages. Note 4: U.V.L.O. is 16V for 3842B/44B and 8.4V for 3843B/45B. Note 5: Hysteresis is 6V for 3842B/44B and 0.8V for 3843B/45B. Note 6: Toggle flip flop used only in 3844B/45B Copyright © 2006 ADDtek Corp. 3 DD019_F -- OCTOBER 2006 AMC3842B/43B/44B/45B Supply Voltage RECOMMENDED OPERATING CONDITIONS Recommended Operating Conditions Parameter Symbol Min. Typ. Max. VCC / VC 30 VI,RT/CT Input Voltage VI,ISENSE/VFB VO, Output ICC IO IO(REF) CT fOSC TA Output Voltage Supply Current Average Output Current Reference Output Current Timing Capacitor Oscillator Frequency Operating Free-air Temperature Units V 0 5.5 V 0 30 25 200 -20 V mA mA mA nF KHz O C 1 100 500 70 0 ELECTRICAL CHARACTERISTICS Unless otherwise specified, these specifications apply over the operating ambient temperature for AMC384XB with 0OC ≤ TA ≤70 OC; VCC = 15V(note 7); RT = 10K;CT = 3.3nF. Low duty cycle pulse testing techniques are used which maintains junction and case temperatures equal to the ambient temperature. Parameter Symbol AMC384XB Test Conditions Units Min. Typ. Max. 4.9 5.0 5.1 V -30 6 6 -100 20 25 -180 mV mV mA 52 0.2 57 1.0 KHz % Reference Section Reference output Voltage VREF TJ = 25 OC, IREF = 1mA Line Regulation Load Regulation Short Ciruit Output Current ISC Oscillator Section Oscillation Frequency f Frequency Change with Voltage Frequency Change with Temperature (note 8) Peak-to-peak Amplitude At RT/CT VOSC Current Sense Section Gain (note 9 & 10) AVOL Maximum Input Signal (note 9) VI(MAX) Power Supply Rejection Ratio (note 9) PSRR Input Bias Current IBIAS Copyright © 2006 ADDtek Corp. 12V ≤ VCC ≤ 25V,TJ = 25 C 1mA ≤ IREF ≤ 20mA TJ = 25 OC O TJ = 25 OC 12V ≤ VCC ≤ 25V 47 TMIN ≤ TA ≤ TMAX COMP = 5V 12V ≤ VCC ≤ 25V (note 9) 4 2.85 0.9 5 % 1.7 V 3.00 1.0 70 -3.0 DD019_F -- 3.15 1.1 -10 V/V V dB µA OCTOBER 2006 AMC3842B/43B/44B/45B ELECTRICAL CHARACTERISTICS (Continued) Error Amplifier Section Input Bias Current Input Voltage Open Loop Voltage Gain Unity Gain Bandwidth (note 8) Power Supply Rejection Ratio Output Sink Current Output Source Current High Output Voltage Low Output Voltage Output Section IBIAS VI(EA) GVO UGBW PSRR ISINK ISOURCE VOH VOL Output Low Level VOL Output High Level VOH Rise Time (note 9) Fall Time (note 9) Under-Voltage Lockout Section Start Threshold tr tf VTH(ST) Min. Operating Voltage COMP = 2.5V 2V ≤ VO ≤ 4V TJ = 25 OC 12V ≤ VCC ≤ 25V VFB = 2.7V, COMP = 1.1V VFB = 2.3V, COMP = 5.0V VFB = 2.3V, RL = 15KΩ to GND VFB = 2.7V, RL = 15KΩ to VREF ISINK = 20mA ISINK = 200mA ISOURCE = 20mA ISOURCE = 200mA TJ = 25 OC, CL = 1nF TJ = 25 OC, CL = 1nF 2.42 65 0.7 60 2 -0.5 5 13 12 -0.1 2.50 90 1 70 7 -1.0 6 0.7 -2 2.58 0.1 1.4 13.5 13.0 50 50 0.4 2.2 150 150 1.1 µA V dB MHz dB mA mA V V V V AMC3842B/44B AMC3843B/45B AMC3842B/44B AMC3843B/45B 14.5 7.8 8.5 7.0 16.0 8.4 10 7.6 17.5 9.0 11.5 8.2 AMC3842B/43B AMC3844B/45B 94 47 97 48 100 50 ns ns V V PWM Section Maximum Duty Cycle Dmax % Total Standby Current Startup Current Operating Supply Current Zener Voltage Note 7: Note 8: Note 9: Note 10: ICC VZ AMC3842B/44B AMC3843B/45B VFB = ISENSE = 0V ICC = 25mA 30 14 35 0.2 0.2 17 mA mA V Adjust VCC above the start threshold before setting at 15V These parameters, although guaranteed, are not 100% tested in production prior to shipment Parameters are measured at trip point of latch with VFB = 2V Gain is measured between ISENSE and COMP with the input changing from 0V to 0.8V Copyright © 2006 ADDtek Corp. 5 DD019_F -- OCTOBER 2006 AMC3842B/43B/44B/45B CHARACTERIZATION CURVES Below characterization curves was referenced by Fig.4 O s cillator D is charge Current vs . Tem perature Maximum Output Duty Cycle vs. Timing Resistor 100 9 Vcc=15V Vosc=2V 8.5 Idischg (mA) Idischg=7.5mA 90 80 Idischg=8.8mA Dmax 70 (%) 60 8 7.5 Vcc=15V Ct=3.3mF TA=25ºC 50 40 7 -50 -25 0 25 50 75 100 0 125 1 2 3 Ø 1.2 30 1 60 0.8 100 Gain 60 Phase Vcc=15V 120 Vth 0.6 (V) 0.4 Vo=2V to 4V 150 0.2 180 0 (dB) 40 90 0 RL=100K -20 10 100 1K 10K 100K TA=-40ºC 1 2 3 Vcc=15V 4 5 6 7 8 Vo(V) 60 Reference Short Circuit Current vs. Temperature. 110 Vcc=15V 50 Vcc=15V RL≤0.1Ω 100 40 90 30 Isc80 (mA) 70 TA=125ºC 8 TA=125ºC 0 1M R e fe re nc e Vol t a ge C ha nge vs. S ourc e C urre nt . 10 7 TA=25ºC f(Hz) 20 6 C urre nt S e nse Input Thre shol d vs. Error Amp Out put Vol t a ge . Error Amp Open-Loop Gain and Phase vs. Frequency 20 5 RT (KΩ ) TA(ºC) 80 4 TA=25ºC TA=-40ºC 60 0 0 20 40 60 80 100 50 120 -50 Iref(mA) Copyright © 2006 ADDtek Corp. -25 0 25 50 75 100 125 150 TA(ºC) 6 DD019_F -- OCTOBER 2006 AMC3842B/43B/44B/45B APPLICATION INFORMATION Error Amp 2R R 1V Current Sense Comparator COMP Rf ISENSE Cf RS GND Fig. 1. Current Sense Circuit Peak current (IS) is set by: IS(MAX) = 1V/RS 2.5V Error Amp VREF 0.5mA RT VFB Zi Zf RT/CT CT COMP GND Fig. 3. Oscillator Section Fig. 2. Error Amplifier Configuration - the For RT < 5K, f = amplifier can source or sink up to 0.5mA 1.72 RTCT VREF RT 4.7K VCC 2N2222 100K 1K Error AMP Adjust 5K 4.7K ISENSE Adjust COMP VREF VFB VCC 0.1µF 1K, 1W Output ISENSE Output RT/CT GND 0.1µF GND Fig. 4. Open-loop laboratory test fixture: CarefulCgrounding techniques are necessary for high peak currents T associated with capacitive loads. Timing and bypass capacitors should be connected to GND pin in a single point ground. The transistor and 5K potentiometer are used to sample the oscillator waveform and apply an adjustable ramp to the ISENSE pin Copyright © 2006 ADDtek Corp. 7 DD019_F -- OCTOBER 2006 AMC3842B/43B/44B/45B APPLICATION INFORMATION (continued) 1K COMP VREF Shutdown 330Ω ISENSE Shutdown 500Ω To Current Sense Resistor Fig. 5. Shutdown Techniques - there are two ways to shutdown the PWM controller: 1) raise the voltage at ISENSE above 1V or, 2) pull the COMP below a voltage two diodes above ground. VREF 0.1µF RT RT/CT CT ISENSE R2 R1 ISENSE RSENSE C Fig 6. Slop Compensation – To achieve duty cycles over 50% for some applications, the above slope compensation technique is suggested by resistively summing a fraction of the oscillator ramp with the current sense signal. Copyright © 2006 ADDtek Corp. 8 DD019_F -- OCTOBER 2006 AMC3842B/43B/44B/45B PACKAGE 8-Pin Plastic DIP INCHES MILLIMETERS 5 8 MIN TYP MAX MIN TYP MAX A 0.355 0.365 0.400 9.02 9.27 10.16 B 0.240 0.250 0.280 6.10 6.35 7.11 - 5.08 5.33 D 0.014 0.018 0.022 0.356 0.46 0.55 F 1.15 1.52 1.65 B 1 4 C A L F G C - 0.200 0.210 0.045 0.060 0.065 - 0.100 - - 2.54 - - 0.090 1.27 - 2.29 J 0.008 0.010 0.015 0.20 0.25 0.38 K 0.115 0.130 0.150 2.92 3.30 3.81 L 0.300 BSC. H 0.050 J K H G M D M 0º 7º 7.62 BSC. 15º 0º 7º 15º 8-Pin Plastic S.O.I.C. INCHES A B MILLIMETERS MIN TYP MAX MIN TYP MAX A 0.183 - 0.202 4.65 - 5.13 B 0.144 0.156 0.163 3.66 3.95 4.14 C 0.068 0.074 1.35 - 1.88 D 0.010 0.016 0.020 0.25 0.41 0.51 F 0.015 0.020 0.035 0.38 0.50 0.89 G 0.050 BSC P - F D G L C SEATING PLAN K J 0.007 - 0.010 0.19 - 0.25 K 0.005 - 0.010 0.13 - 0.25 L 0.189 - 0.205 4.80 - 5.21 M 0º - 8º 0º - 8º 5.79 6.00 6.20 M J P Copyright © 2006 ADDtek Corp. 1.27 BSC 9 0.228 0.236 0.244 DD019_F -- OCTOBER 2006 AMC3842B/43B/44B/45B 14-Pin Plastic S.O.I.C. INCHES A B P F G TYP MAX MIN TYP MAX A 0.336 - 0.344 8.54 - 8.74 B 0.159 - 0.158 3.81 - 4.01 C 0.053 - 0.069 1.35 - 1.75 D 0.014 - 0.018 0.35 - 0.46 F - 0.030 0.67 - 0.77 0.026 G C Copyright © 2006 ADDtek Corp. MIN D L SEATING PLAN MILLIMETERS K M J 10 0.050 BSC 1.27 BSC J 0.007 - 0.010 0.19 - 0.25 K 0.004 - 0.010 0.10 - 0.25 L 0.189 - 0.205 4.82 - 5.21 M - - 8º - - 8º P 0.228 - 0.244 5.79 - 6.20 DD019_F -- OCTOBER 2006 AMC3842B/43B/44B/45B IMPORTANT NOTICE ADDtek reserves the right to make changes to its products or to discontinue any integrated circuit product or service without notice, and advises its customers to obtain the latest version of relevant information to verify, before placing orders, that the information being relied on is current. A few applications using integrated circuit products may involve potential risks of death, personal injury, or severe property or environmental damage. ADDtek integrated circuit products are not designed, intended, authorized, or warranted to be suitable for use in life-support applications, devices or systems or other critical applications. Use of ADDtek products in such applications is understood to be fully at the risk of the customer. In order to minimize risks associated with the customer’s applications, the customer should provide adequate design and operating safeguards. ADDtek assumes to no liability to customer product design or application support. ADDtek warrants the performance of its products to the specifications applicable at the time of sale. ADDtek Corp. 9F, No. 20, Sec. 3, Bade Rd., Taipei, Taiwan, 105 TEL: 2-25700299 FAX: 2-25700196 Copyright © 2006 ADDtek Corp. 11 DD019_F -- OCTOBER 2006