MSP430FR2033 Datasheet, PDF (73/89 Pages) Texas Instruments – Mixed-Signal Microcontrollers

www.ti.com
MSP430FR2033, MSP430FR2032
SLASE45B – OCTOBER 2014 – REVISED AUGUST 2015
Figure 7-5 shows the recommended decoupling circuit when an external voltage reference is used. The
internal reference module has a maximum drive current as described in the sections ADC Pin Enable and
1.2-V Reference Settings of the MSP430FR4xx and MSP430FR2xx Family User's Guide (SLAU445).
The reference voltage must be a stable voltage for accurate measurements. The capacitor values that are
selected in the general guidelines filter out the high- and low-frequency ripple before the reference voltage
enters the device. In this case, the 10-μF capacitor is used to buffer the reference pin and filter any low-
frequency ripple. A bypass capacitor of 100 nF is used to filter out any high-frequency noise.
7.2.1.3 Layout Guidelines
Components that are shown in the partial schematic (see Figure 7-5) should be placed as close as
possible to the respective device pins to avoid long traces, because they add additional parasitic
capacitance, inductance, and resistance on the signal.
Avoid routing analog input signals close to a high-frequency pin (for example, a high-frequency PWM),
because the high-frequency switching can be coupled into the analog signal.
Copyright © 2014–2015, Texas Instruments Incorporated
Applications, Implementation, and Layout
73
Submit Documentation Feedback
Product Folder Links: MSP430FR2033 MSP430FR2032