AZ3844M

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AAT(类比)
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描述：
AZ3844M - CURRENT MODE PWM CONTROLLER - Advanced Analog Technology, Inc.

数据手册：

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AZ3844M 数据手册

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 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 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 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

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AZ3844M

1. 物料型号： - AZ3842/3/4/5，这些是高绩效固定频率电流模式PWM控制器系列。

2. 器件简介： - AZ3842/3/4/5系列集成电路为离线和DC-DC转换器应用而优化，最少化外部组件需求。它们具有低启动电流的欠压锁定（UVLO）电路、精确控制占空比的校准振荡器、提供最大电流限制的电流感应比较器，以及增加输出电流的图腾柱输出阶段。此外，这些IC还具有精确的过温保护、过流保护和最大输出功率保护。

3. 引脚分配： - 8脚和14脚的SOIC封装，以及DIP-8封装。具体引脚功能如下： - COMP（1/14脚）：误差放大器输出，用于环路补偿。 - VFB（2/3脚）：误差放大器反相输入，通常通过电阻分压器连接到开关电源输出。 - ISENSE（3/5脚）：连接与电感电流成比例的电压，PWM使用此信息来终止输出开关导通。 - RT/CT（4/7脚）：通过连接电阻Rr到VREF和电容Cr到地来编程振荡器频率和最大输出占空比，可操作至500kHz。 - GND（5/9脚）：控制电路和电源地。 - OUTPUT（6/10脚）：直接驱动功率MOSFET的门极，此引脚可源/汇1.0A的峰值电流。 - Vcc（7/12脚）：控制IC的正电源。 - VREF（8/14脚）：参考输出，为电容Cr通过电阻RT提供充电电流。 - PWR GND（8脚）、PWR Vc（11脚）和NC（无连接，2,4,6,13脚）。

4. 参数特性： - 低线压调节：4mV。 - 低负载调节：4mV。 - 参考电压在全温度范围内的高稳定性：0.2mV/°C。 - 工作频率高达500kHz。 - 高PWM频率稳定性在全温度范围内：2.5%。 - 高PWM频率稳定性在全供电电压范围内：0.2%。 - 精确的过温保护带迟滞，UVLO带迟滞。

5. 功能详解： - AZ3842/3/4/5系列提供了鲁棒的$V_{REF}$线/负载调节、高稳定性的参考电压、高达500kHz的振荡频率、精确的过温保护等功能。

6. 应用信息： - 应用于离线转换器、DC-DC转换器、电压适配器、CRT监视器电源、桌面电源、DVD/STB电源等。

7. 封装信息： - 提供SOIC-8、DIP-8和SOIC-14三种封装类型，具体型号如下： - SOIC-8：AZ3842/3/4/5M。 - DIP-8：AZ3842/3/4/5P。 - SOIC-14：AZ3842/3/4/5MM。

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