STM32L151xx LQFP100 VDDA VREF range

[Pavel Krupets]

Reference manual RM0038

5.1.1 Independent A/D and DAC converter supply and reference voltage

On BGA 64-pin and all packages with 100 pins or more

I need a bit of clarification on correct voltage ranges for VDDA and VREF+:

2.4 V ≤ VREF+ = VDDA

Does it mean that VREF+ must be equal to VDDA? For instance I have a VREF 2.5V should VDDA be 2.5V as well or can I use 3.3V for VDDA?

[Pavel Krupets]

It seems so for max speed. VREF+ = VDDA for 16 MHz ADC.

From:

STM32L151xE STM32L152xE Datasheet - production data

6.3.17 12-bit ADC characteristics

Table 54. ADC clock frequency