ADI ADM12914 精度0.8%四路电源电压监视方案

ADI 公司的ADM12914是精度为+/-0.8%的四路电源电压监视集成电路,用来监视各种应用的电源电压. ADM12914每路监视有两个专用输入引脚VHx和VLx,为过压(OV)和欠压(UV)条件监视. ADM12914能监视多达2个负电源,可调的UV和OV输入阈值, 阈值精度高达+/-1.5%,具有漏极开路UV和OV重置输出和尖峰免疫功能,消耗电流仅为62uA,可用在服务器电源监视,FPGA/DSP核和I/O电压监视,通信设备和医疗设备.本文介绍了ADM12914的主要特性,功能方框图, 典型应用框图以及监视四种电压的多个应用框图.

The ADM12914 is a quad voltage supervisory IC ideally suited for monitoring multiple rails in a wide range of applications. Each monitored rail has two dedicated input pins, VHx and VLx, which allows each rail to be monitored for both undervoltage (UV) and overvoltage (OV) conditions with high accuracy of ±0.8%. Common active low undervoltage (UV) and overvoltage (OV) pins are shared by each of the monitored voltage rails.

The ADM12914 includes a 1 V buffered reference output, REF, that acts as an offset when monitoring a negative voltage. The tristate SEL pin determines the polarity of the third and fourth inputs, that is, configures the device to monitor positive or negative supplies.

The device incorporates an internal shunt regulator that enables the device to be used in higher voltage systems. This feature requires a resistor to be placed between the main supply rail and the VCC pin to limit the current flow into the VCC pin at a level no greater than 10 mA. The ADM12914 uses the internal shunt regulator to regulate VCC if the supply line should exceed the absolute maximum ratings.

The ADM12914 is available in two models. The ADM12914-1 offers a latching overvoltage output that can be cleared by toggling the LATCH input pin. The ADM12914-2 has a disable pin that can override and disable both the UV and the OV output signals.

The ADM12914 is available in a 16-lead QSOP package. The device operates over the extended temperature range of −40℃ to +125℃.

ADM12914主要特性:

Quad undervoltage/overvoltage (UV/OV) positive/negative supervisor

Supervises up to two negative rails

Adjustable UV and OV input thresholds

Industry leading threshold accuracy over the extended temperature range: ±0.8% 1 V buffered reference output

Open-drain UV and OV reset outputs

Adjustable reset timeout with disable option

Outputs guaranteed down to VCC of 1 V

Glitch immunity

62 μA supply current 16-lead QSOP package

Specified from −40℃ to +125℃

ADM12914应用:

Server supply monitoring

FPGA/DSP core and I/O voltage monitoring

Telecommunications equipment

Medical equipment


图1.ADM12914功能方框图



图2.ADM12914典型应用框图



图3.ADM12914监视5V,3.3V,2.5V和1.8V的典型应用框图(电源容差1.5%,输入容差5%)



图4.ADM12914监视12V(电源容差1.5%,输入容差5%)和-12V(电源容差3%,输入容差15%)的典型应用框图