MSP430FR2111IPW16R低功耗问题

我的解决方式如下：
        MCU休眠时，设置为LPM4，然后RTC定时器选择VLOCLK作为时钟源，现在整机功耗为0.65uA~1.75uA；
RTC设置如下：
void Init_TRC_Mode()
{
    // RTC count re-load compare value at 32.
    // 1024/32768 * 32 = 1 sec.
    RTCMOD = 64-1;
    RTCCTL = RTCSS__VLOCLK | RTCSR | RTCPS__1024 | RTCIE;
}

VLOCLK介绍在：MSP430FR4xx and MSP430FR2xx FamilyUser's Guide 的第102页：

The internal VLO provides a typical frequency of 10 kHz (see the device-specific data sheet for
parameters) without requiring a crystal. The VLO provides for a low-cost low-power clock source for
applications that do not require an accurate time base.
VLOCLK is active in the following conditions:
• VLO is selected as the source of MCLK and SMCLK (SELMS = {3}), and MCLK or SMCLK is active.
• The VLOAUTOOFF bit is cleared and the MCU is in AM through LPM4.
• At least one peripheral requests VLO as clock source.

在测试中，发现另外一个问题，我焊接了5个样机，其中有2个样机的待机功耗为0.65uA，另外3个样机的功耗为1.65~1.75uA之间，这是这个MCU在待机时体现出来的差异性吗？是正常现象还是非正常现象？请解惑，谢谢！

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