The MAX1970 was developed as a dual 600mA buck converter for input voltages as low as 2.6V and output voltages down to 1.2V. However, many current generation CPUs require core supplies of 1V or less. The MAX1970 can be reconfigured with an alternate output feedback sensing circuit to meet this requirement with no sacrifice in regulation. Internally the non-inverting input of the MAX1970's error amplifier is connected to 1.20V reference, which yields a feed back threshold of 1.20V. The circuit of Figure 1 uses the 2.5V logic supply (Vout2) to bias the feedback divider resistor network, R2 and R3, enabling the other output voltage, Vout1, to be set as: Vout1 = 1.20V (Vout2 1.20V) (R2/R3) As seen from the equation above, Vout2 must be greater than 1.20V for Vout1 to be less than 1.20V. In Figure 1, R2 equals to 2K, hence Vout1 = 1.0V. Vout2 is internally program to 2.5V via FBSEL2 (Refer to MAX1970 Data Sheets). Table 1 below shows the measured results of the line, load and cross regulation of Figure 1. Figure 1. Typical application circuit for 3.3V ±10% input. Table 1. Measured Results of Line, Load and Cross Regulation    Vin    Iout1    Vout1    Iout2    Vout2    3.0V    10mA    1.001V    10mA    2.507V    3.0V    10mA    1.001V    600mA    2.505V    3.0V    600mA    0.998V    600mA    2.505V    3.0V    600mA    0.998V    10mA    2.507V    3.3V    10mA    1.001V    10mA    2.507V    3.3V    10mA    1.001V    600mA    2.505V    3.3V    600mA    0.998V    600mA    2.505V    3.3V    600mA    0.998V    10mA    2.507V    3.6V    10mA    1.001V    10mA    2.507V    3.6V    10mA    1.001V    600mA    2.505V    3.6V    600mA    1.000V    600mA    2.505V    3.6V    600mA    1.000V    10mA    2.507V As seen from Table 1, the worst-case voltage variation for Vout1, the 1.0V output, is less than 0.3% for all combination of input voltages from 3.0V to 3.6V, and output currents from 10mA to 600mA. 相关型号   APP 959: Feb 06, 2002 MAX1970 双路、180°异相、1.4MHz、750mA、降压型调节器，带有POR和RSI/PFO 完整的数据资料 (PDF, 276kB) 免费样品 自动更新 需要自动接收最新发布的应用笔记吗？请订阅EE-Mail™ (English only)。 我们期待您的反馈！ 喜欢？不喜欢？有待改善？或为我们提供建议？请与我们联系 — 我们将根据您的意见或建议改善我们的工作。 网页评价或提供建议   下载，PDF格式 (42kB)  AN959, AN 959, APP959, Appnote959, Appnote 959