SPRS797F November 2012 – September 2021 TMS320F28050 , TMS320F28051 , TMS320F28052 , TMS320F28052F , TMS320F28052M , TMS320F28053 , TMS320F28054 , TMS320F28054F , TMS320F28054M , TMS320F28055
PRODUCTION DATA
The on-chip crystal oscillator X1 and X2 pins are 1.8-V level signals and must never have 3.3-V level signals applied to them. If a system 3.3-V external oscillator is to be used as a clock source, it should be connected to the XCLKIN pin only. The X1 pin is not intended to be used as a single-ended clock input, it should be used with X2 and a crystal.
Table 8-18 lists the typical specifications for the external quartz crystal (fundamental mode, parallel resonant). Furthermore, ESR range = 30 to 150 Ω. For Table 8-18, Cshunt should be less than or equal to 5 pF.
| FREQUENCY (MHz) | Rd (Ω) | CL1 (pF) | CL2 (pF) |
|---|---|---|---|
| 5 | 2200 | 18 | 18 |
| 10 | 470 | 15 | 15 |
| 15 | 0 | 15 | 15 |
| 20 | 0 | 12 | 12 |
Figure 8-8 Using the On-chip Crystal Oscillator
Figure 8-9 Using a 3.3-V External Oscillator