基于TPS3890具有可编程延迟的低静态电流、1% 精度监控器

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基于TPS3890具有可编程延迟的低静态电流、1% 精度监控器

　　1 特性

　　上电复位 (POR) 发生器，可调节延迟时间：40μs 至 30s

　　超低静态电流：2.1μA(典型值)

　　高阈值精度：1%(最大值)

　　高精度迟滞

　　固定和可调节阈值电压：

　　固定阈值适用于标准电压轨：

　　1.2V 到 3.3V

　　可调节阈值电压低至 1.15V

　　手动复位 (MR) 输入

　　开漏 RESET 输出

　　温度范围：-40°C 至 +125°C

　　封装：1.5mm × 1.5mm 晶圆级小外形无引线 (WSON) 封装

　　2 应用

　　数字信号处理器 (DSP) 或微控制器

　　现场可编程门阵列 (FPGA)、专用集成电路 (ASIC)

　　笔记本电脑、台式计算机

　　智能手机，手持产品

　　便携式电池供电产品

　　固态硬盘

　　机顶盒

　　工业控制系统

　　3 说明

TPS3890 是一款静态电流较低的精密电压监控器，可监视低至 1.15V 的系统电压，开漏 RESET 信号在 SENSE 电压降至低于预设阈值或手动复位 (MR) 引脚降为逻辑低电平时置为有效。RESET 输出在用户可调节延迟时间内保持低电平，条件是 SENSE 电压和手动复位 (MR) 返回至超出相应阈值。TPS3890 系列使用精密电压实现 1% 的阈值精度。通过将 CT 引脚与外部电容相连，可在 40μs 到 30s 范围内调节复位延迟时间。TPS3890 具有 2.1μA 的超低静态电流，采用 1.5mm × 1.5mm 小型封装，使得器件非常适用于电池供电和空间受限 应用。该器件的额定工作温度范围为 -40℃ 至 +125℃ (TJ)。

TI产品现货库存在线购买：https://www.iczoom.com/brand/509-c-1-20.html

　　The primary constraint for this application is choosing the correct device to monitor the supply voltage of the microprocessor. The TPS389018 has a negative threshold of 1.73 V and a positive threshold of 1.74 V, making the device suitable for monitoring a 1.8-V rail. The secondary constraint for this application is the reset delay time that must be at least 1 ms to allow the Delfino microprocessor enough time to startup up correctly. Because a minimum time is required, the worst-case scenario is a supervisor with a high CT charging current (ICT) and a low CT comparator threshold (VCT). For applications with ambient temperatures ranging from –40°C to +125°C, CCT can be calculated using ICT(Max), VCT(MIN), and solving for CCT in Equation 1 such that the minimum capacitance required at the CT pin is 1.149 nF. If standard capacitors with ±20% tolerances are used, then the CT capacitor must be 1.5 nF or larger to ensure that the 1-ms delay time is met.

　　A 0.1-µF decoupling capacitor is connected to the VDD pin as a good analog design practice and a 1-MΩ resistor is used as the RESET pullup resistor to minimize the current consumption when RESET is asserted. The MR pin can be connected to an external signal if desired or connected to VDD if not used.