LDO输出电压大

庚0209

使用的大电流LDO，MIC29302，输出电压应该为3.8V，实际为4.3V，但是有的时候输出也能正常恢复为3.8V，输入是5V，搞不清楚问什么。

之前输入是12V的时候，输出还是正常的。

HNTA_401

先贴个原理图和PCB图吧

lize314

规格书：The MIC2915x–2975x regulators are specified between finite loads. If the output current is too small, leakage currents dominate and the output voltage rises. The following minimum load current swamps any expected leakage current across the operating temperature range, as shown in Table 4-2.
; U: B$ c, @0 _$ J
  L: X& {+ [% u' U0 ?$ yMIC2915x–2975x调节器是在有限载荷之间指定的。如果输出电流太小，泄漏电流占主导地位，输出电压上升。
6 x& R5 m: l9 Z- F+ @8 |; W& T) }
是不是空载测的电压上升？

庚0209

lize314 发表于 2023-4-26 15:45
规格书：The MIC2915x–2975x regulators are specified between finite loads. If the output current is  ...

. W0 U7 l% ^, |# r1 l应该是这个原因，负载打开了之后，就好了
6 R, u- z, m2 e# C& H9 l

超級狗

, S7 z9 m$ L3 |( M# x4.3 Minimum Load Current
" c! A0 b' C' ~& T# yThe MIC2915x–2975x regulators are specifiedbetween finite loads. If the output current is too small, leakage currents dominate and the output voltage rises. The following minimum load current swamps anyexpected leakage current across the operatingtemperature range, as shown in Table 4-2.



9 X3 ?0 R) L% T/ Q9 {* m( }. ]

yhg-cad

这个IC有最小负载电流要求，对GND加个负载电阻，手册上有说的