(AZ3842 - AZ3845) CURRENT MODE PWM CONTROLLER

www.DataSheet4U.com Advanced Analog Circuits Data Sheet AZ3842/3/4/5 Features · Robust VREF Line/Load Regulation Low Line Regulation : 4mV Low Load Regulation : 4mV High Stability of Reference Voltage over a Full Temperature Range: 0.2mV/ oC Operating Frequency up to 500KHz High PWM Frequency Stability over a Full Temperature Range: 2.5% High PWM Frequency Stability under a Full Supply Voltage Range: 0.2% Accurate Over-temperature Protection with Hysteresis UVLO with Hysteresis CURRENT MODE PWM CONTROLLER General Description The AZ3842/3/4/5 are high performance fixed frequency current-mode PWM controller series. These integrated circuits are optimized for off-line and DC-DC converter applications with minimum external components. They feature under-voltage lockout (UVLO) circuit for low start-up current, trimmed oscillator for precise duty cycle control, current sense comparator providing maximum current limiting and a totem pole output stage for increasing output current. In addition, these ICs also feature accurate protection against over-temperature, over-current and maximal output power. The AZ3842 and AZ3844 have UVLO thresholds of 15.5V(on) and 10V(off); The corresponding thresholds for AZ3843 and AZ3845 are 8.4 V(on) and 7.8V(off). The AZ3842 and AZ3843 can operate approaching 100% duty cycle; AZ3844 and AZ3845 can operate from zero to 50% duty cycle. These ICs are available in 3 packages: SOIC-8, DIP-8 and SOIC-14. · · · · · · Applications · · · · · · Off-line Converter DC-DC Converter Voltage Adapter CRT Monitor Power Supply Desktop Power Supply DVD/STB Power Supply SOIC-8 DIP-8 SOIC-14 Figure 1. Package Types of AZ3842/3/4/5 March 2003 1 Rev: 1.0 DataSheet 4 U .com www.DataSheet4U.com Advanced Analog Circuits Data Sheet AZ3842/3/4/5 M Package (SOIC-14) COMP 1 2 3 4 5 6 7 14 13 12 11 10 9 8 VREF N/C VCC PWR VC OUTPUT GND PWR GND CURRENT MODE PWM CONTROLLER Pin Configuration P/M Package (DIP-8/SOIC-8) COMP VFB ISENSE RT/CT 1 2 3 4 8 7 6 5 VREF VCC OUTPUT GND N/C VFB N/C ISENSE N/C RT/CT Figure 2. Pin Configuration of AZ3842/3/4/5 (Top View) Pin Description Pin Number 8-pin 1 2 3 4 14-pin 1 3 5 7 Pin Name COMP VFB ISENSE RT/CT Function This pin is the Error Amplifier output and is made available for loop compensation. The inverting input of the Error Amplifier. It is normally connected to the switching power supply output through a resistor divider. A voltage proportional to inductor current is connected to this input. The PWM uses this information to terminate the output switch conduction. The Oscillator frequency and maximum Output duty cycle are programmed by connecting resistor RT to VREF and capacitor CT to ground. Operation to 500 kHz is possible. The combined control circuitry and power ground. This output directly drives the gate of a power MOSFET. Peak currents up to 1.0 A are sourced and sunk by this pin. The positive supply of the control IC. This is the reference output. It provides charging current for capacitor CT through resistor RT. This pin is a separate power ground return that is connected back to the power source. It is used to reduce the effects of switching transient noise on the control circuitry. The Output high state (VOH) is set by the voltage applied to this pin. With a separate power source connection, it can reduce the effects of switching transient noise on the control circuitry. This pin is the control circuitry ground return and is connected back to the power source ground. No connection. These pins are not internally connected. 5 6 7 8 10 12 14 8 11 GND OUTPUT VCC VREF PWR GND PWR VC 9 2,4,6,13 GND N/C March 2003 2 Rev: 1.0 DataSheet 4 U .com www.DataSheet4U.com Advanced Analog Circuits Data Sheet AZ3842/3/4/5 CURRENT MODE PWM CONTROLLER Functional Block Diagram VCC GND 7(12) 34V 5(9) UVLO S/R 5V REF 7(11) VCC (PWR VC) VREF 8(14) INTERNAL BIAS 2.50V VREF GOOD LOGIC RT/CT 4(7) OSC T (Note) 6(10) OUTPUT GND (PWR GND) A(B) A for 8-pin B for 14-pin OVER TEMP PROTECT ERROR AMP 2(3) 1(1) 3(5) R 1V 2R 5(8) S R CURRENT SENSE COMPARATOR PWN LATCH Note: Toggle flip-flop used for 3844/45 only VFB COMP ISENSE Figure 3. Functional Block Diagram of AZ3842/3/4/5 Ordering Information Package SOIC-8 DIP-8 SOIC-14 Temperature Range Part Number AZ3842/3/4/5M AZ3842/3/4/5P AZ3842/3/4/5MM Marking ID 3842/3/4/5M AZ3842/3/4/5P AZ3842/3/4/5MM Packing Type Tape/Reel/Tube Tube Tape/Reel -40oC~85oC March 2003 3 Rev: 1.0 DataSheet 4 U .com www.DataSheet4U.com Advanced Analog Circuits Data Sheet AZ3842/3/4/5 CURRENT MODE PWM CONTROLLER Absolute Maximum Ratings (Note 1, 2) Parameter Supply Voltage Output Current Analog Inputs (8-pin: pin2,3, 14-pin: pin3,5) Error Amp Output Sink Current Power Dissipation at TA< 25 oC (DIP-8) Power Dissipation at TA<25 oC (SOIC-8) Power Dissipation at TA<25 oC (SOIC-14) Storage Temperature Range Lead Temperature (Soldering, 10sec) Symbol Vcc Io V(ANA) ISINK(E.A) PD (Note 3) PD (Note 3) PD (Note 3) TSTG TLEAD Value 30 土1 -0.3 to 6.3 10 1000 460 725 -65 ~+150 +300 Unit V A V mA mW mW mW o o C C Note 1: Stresses greater than those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under "Recommended Operating Conditions" is not implied. Exposure to "Absolute Maximum Ratings" for extended periods may affect device reliability. Note 2: All voltages are with respect to pin 5 and all currents are positive into specified terminal. Note 3: Board thickness 1.6mm, board dimension 90mm x 90mm. Recommended Operating Conditions Parameter Oscillation Frequency Symbol f TA Min -40 Max 500 85 Unit KHz o Ambient Temperature C March 2003 4 Rev: 1.0 DataSheet 4 U .com www.DataSheet4U.com Advanced Analog Circuits Data Sheet AZ3842/3/4/5 CURRENT MODE PWM CONTROLLER Electrical Characteristics (VCC=15V, RT=10kΩ CT=3.3nF, TA= -40oC to +85oC, unless otherwise specified.) Parameter REFERENCE SECTION Reference Output Voltage Line Regulation Load Regulation Short Circuit Output Current Temperature Stability Output Noise Voltage Long Term Stability OSCILLATOR SECTION Oscillation Frequency Frequency Change with Voltage Oscillator Amplitude Temperature Stability ERROR AMPLIFIER SECTION Input Bias Current Input Voltage Open Loop Voltage Gain Power Supply Rejection Ratio Output Sink Current Output Source Current High Output Voltage Low Output Voltage CURRENT SENSE SECTION Gain Maximum Input Signal Power Supply Rejection Ratio Input Bias Current Delay to Output OUTPUT SECTION Low Output Voltage High Output Voltage Rise Time VOL VOH tR ISINK = 20mA ISINK = 200mA ISOURCE = 20mA ISOURCE = 200mA TJ=25oC, CL=1nF (Note 6) 13 12 GV VI(MAX) PSRR IBIAS Vpin3 = 0 to 2V (Note 6) (Note 4, 5) Vpin1=5V(Note 4) 12V ≤ VCC ≤ 25V (Note 4, 6) 2.85 0.9 IBIAS VI AVOL PSRR ISINK ISOURCE VOH VOL (Note 6) Vpin 1=2.5V 2V ≤ VO ≤ 4V 12V ≤ VCC ≤ 25V Vpin2=2.7V, Vpin1=1.1V Vpin2=2.3V, Vpin1=5V Vpin2=2.3V, RL=15kΩ to GND Vpin2=2.7V, RL=15kΩ to Pin 8 2.42 65 60 2 -0.5 5 f ∆f/f VOSC TJ=25oC 12V ≤ VCC ≤ 25V Pin 4, peak to peak (Note 6) (Note 6) 47 (Note 6) TA=85 C, 1000 hours o Symbol Conditions Min Typ Max Unit VREF ∆VREF ∆VREF ISC TJ=25oC, IREF=1mA 12V ≤ VCC ≤25V 1mA ≤ IREF ≤20mA TA=25oC 4.90 5.00 4 4 -100 0.2 50 5 52 0.2 1.7 2.5 -0.1 2.50 90 70 4 -0.8 6 0.8 3 1 70 -3 150 0.1 1.4 14 13 50 5.10 15 15 -180 0.4 25 57 1 V mV mV mA mV/oC µV mV KHz % V % -2 2.58 µA V dB dB mA mA V 1.1 3.15 1.1 -10 300 0.4 2.2 V V/V V dB µA ns V V V V 150 ns March 2003 5 Rev: 1.0 DataSheet 4 U .com www.DataSheet4U.com Advanced Analog Circuits Data Sheet AZ3842/3/4/5 CURRENT MODE PWM CONTROLLER Electrical Characteristics (Continued) Parameter Fall Time Symbol tF Conditions TJ=25oC, CL=1nF (Note 6) AZ3842/AZ3844 AZ3843/AZ3845 AZ3842/AZ3844 AZ3843/AZ3845 AZ3842/AZ3843 AZ3844/AZ3845 14.5 7.8 8.5 7.0 93 46 Min Typ 50 15.5 8.4 10.0 7.6 95 48 Max 150 16.5 9.0 11.5 8.2 100 50 0 Unit ns V V V V % % % mA mA V o UNDER -VOLTAGE LOCKOUT SECTION Start Threshold VTH(ST) Min. Operation Voltage (After Turn On) PWM SECTION Max. Duty Cycle Min. Duty Cycle Start-Up Current Operating Supply Current Zener Voltage Shutdown Temperature Temperature Hysteresis D(Max.) D(Max.) D(Min.) IST ICC(OPR) VZ TSHUT THYS VOPR (Min.) TOTAL STANDBY CURRENT SECTION 0.6 Vpin3=Vpin2=0V ICC=25mA (Note 6) (Note 6) 30 10 34 165 25 1 14 OVER-TEMPERATURE PROTECT SECTION C oC Note 4: Parameters are tested at trip point of latch with Vpin2 = 0. Note 5: Here gain is defined as: ∆VPin 1 A= , 0 ≤ Vpin3 ≤ 0.8V ∆VPin 3 Note 6: These parameters, although guaranteed, are not 100% tested in production. VREF 4.7k RT 2N2222 COMP 1k ERROR AMP ADJUST 4.7k 100k VFB 5k ISENSE ADJUST ISENSE RT/CT 2 7 1 A AZ3842 8 VCC VREF VCC 0.1µf OUTPUT GND 1K 1W OUTPUT 0.1µf 3 6 4 5 CT GND Figure 4. Basic Test Circuit March 2003 6 Rev: 1.0 DataSheet 4 U .com www.DataSheet4U.com Advanced Analog Circuits Data Sheet AZ3842/3/4/5 CURRENT MODE PWM CONTROLLER Electrical Characteristics (Continued) Figure 4 is the basic test circuit for AZ384x. In testing, the high peak currents associated with capacitive loads necessitate careful grounding techniques. Timing and bypass capacitors should be connected close to pin 5 in a single point ground. The transistor and 5k potentiometer are used to sample the oscillator waveform and apply an adjustable ramp to pin 3. Typical Performance Characteristics 100k 30 10 50K Dead Time (µs) CT 3 RT (Ω) n =1 CT 0n =1 F CT 10k F n 00 =1 1 5K F 0.3 1 2.2 4.7 10 22 47 100 100 1k 10k 100k 1M Timing Capacitor (nF) Frequency (Hz) Figure 5. Oscillator Dead Time vs. Timing Capacitor 1.0 Figure 6. Timing Resistor vs. Frequency 5.015 5.010 5.005 5.000 4.995 4.990 4.985 VCC=15V, IO=1mA 0.9 AZ3842 Reference Voltage (V) Start Up Current (m