原标题：Allegro ARG81800超低静态电流1A同步降压稳压器解决方案

　　Allegro公司的ARG81800是超低静态电流宽输入1A同步降压稳压器,包括所有控制和保护电路, PWM稳压器输出电压精度±1.5%,在非常轻负载消耗最小的电流,有两个版本:500mA和1A.所以对于更低电流的系统,物理尺寸和功率元件可优化,以降低PCB面积和节省成本.PWM开关频率可编程,以平衡效率,元件尺寸和EMC性能.器件满足汽车AEC-Q100规范.输入工作电压3.5V到36V,经受浪涌电压到40V,低功耗(LP)模式在3.3V或5.0V VOUT时仅消耗8 μA, AUTO模式基于负载电流在PWM和LP模式自动转换.可编PWM频率(fSW)为250 kHz 到 2.4 MHz,工作温度范围‒40°C到 150°C内可调输出范围±1.5%精度.主要用在信息娱乐设备,导航系统,仪表盘,音频系统,ADAS应用,电池供电的系统,工业系统,网络和通信,家庭音响和HVAC系统.本文介绍了ARG81800主要特性和优势, 功能框图和应用框图,多种应用电路和两种参考设计及其材料清单,以及ALLEGRO ARG81800演示板通用指标,电路图,材料清单和PCB设计图.

　　The ARG81800 includes all the control and protection circuitry to produce a PWM regulator with ±1.5% output voltage accuracy, with ultralow quiescent current to enable “keepalive” supply operation with minimal current draw from the supply during very light load regulation. There are two versions of the ARG81800 available, 500 mA and 1 A, so the physical size of the power components can be optimized for lower current systems, thus reducing PCB area and saving cost. PWM switching frequency can be programmed over a wide range to balance efficiency, component sizing, and EMC performance. If VIN decays and the duty cycle reaches its maximum, the ARG81800 will automatically fold back its PWM frequency to extend the duty cycle and maintain VOUT.

　　The ARG81800 employs Low-Power (LP) mode to maintain the output voltage at no load or very light load conditions while drawing only micro-amps from VIN. The ARG81800 includes a PWM/AUTO control pin so the system can dynamically force either PWM or AUTO mode by setting this pin high or low, respectively.

　　If the SYNCIN pin is driven by an external clock, the ARG81800 will be forced into PWM mode and synchronize to the incoming clock. The ARG81800 adds frequency dithering to the SYNCIN clock to reduce EMI/EMC. The ARG81800 provides a CLKOUT pin so “downstream” regulators can be easily interleaved and dithered via their synchronization inputs.

　　ARG81800主要特性和优势:

　　Automotive AEC-Q100 qualified

　　Input operating voltage range: 3.5 to 36 V Withstands surge voltages to 40 V for load dump

　　Low-Power (LP) mode—draws just 8 μA from VIN while maintaining 3.3 or 5.0 VOUT

　　AUTO mode allows automatic transition between PWM and LP mode based on load current

　　Programmable PWM frequency (fSW): 250 kHz to 2.4 MHz

　　PWM frequency dithering and controlled switch node slew rate reduce EMI/EMC signature

　　CLKOUT allows interleaving and dithering of “downstream” regulators using their synchronization inputs

　　Interleaving minimizes input filter capacitor requirement and improves EMI/EMC performance

　　Synchronization of PWM frequency to external clock on SYNCIN pin

　　Adjustable output voltage: ±1.5% accuracy over operating temperature range (‒40℃ to 150℃)

　　Maximized duty cycle at low VIN improves dropout

　　Soft recovery from dropout condition

　　Adjustable soft-start time controls inrush current to accommodate a wide range of output capacitances

　　External compensation provides flexibility to tune the system for maximum stability or fast transient response

　　ARG81800应用:

　　Infotainment

　　Navigation Systems

　　Instrument Clusters

　　Audio Systems

　　ADAS Applications

　　Battery Powered Systems

　　Industrial Systems

　　Network and Telecom

　　Home Audio

　　HVAC Systems

　　图1. ARG81800功能框图

　　图2. ARG81800典型应用框图

　　图3. ARG81800主-跟随器配置图

　　图4. ARG81800 PCB布局以最小化电磁辐射

　　图5. ARG81800应用电路:3.3V/1A带输入EMI滤波器的降压稳压器

　　图6. ARG81800参考设计1:AUTO模式带CLKOUT使能, VIN = 3.5-36 V, VOUT = 3.3 V, IOUT = 0 - 1.0 A, fSW = 2.15 MHz

　　参考设计1推荐材料清单:

　　图7. ARG81800参考设计2:强迫PWM模式带CLKOUT不能, VIN = 3.5-36 V, VOUT =5.0 V, IOUT = 0 – 0.5 A, fSW = 400 kHz

　　参考设计2推荐材料清单:

　　图8. ALLEGRO ARG81800演示板外形图

　　演示板通用指标:

　　ALLEGRO ARG81800演示板材料清单: