MSP430FE42X2 Datasheet, PDF (28/48 Pages) Texas Instruments – MIXED SIGNAL MICROCONTROLLER

MSP430FE42x2
MIXED SIGNAL MICROCONTROLLER
SLAS616 − JULY 2008
electrical characteristics over recommended operating free-air temperature (unless otherwise
noted) (continued)
crystal oscillator, LFXT1 oscillator (see Notes 1 and 2)
C_XIN
PARAMETER
Integrated input capacitance
(see Note 4)
TEST CONDITIONS
V_CC
OSCCAPx = 0h
3V
OSCCAPx = 1h
3V
OSCCAPx = 2h
3V
MIN
TYP MAX
UNIT
0
10
pF
14
OSCCAPx = 3h
3V
18
OSCCAPx = 0h
3V
0
C_XOUT
Integrated output capacitance
(see Note 4)
OSCCAPx = 1h
3V
OSCCAPx = 2h
3V
10
pF
14
OSCCAPx = 3h
3V
18
V_IL
V_IH
NOTES:
Low-level input voltage at XIN
High-level input voltage at XIN
See Note 3
V_SS
2.2 V/3 V
0.8×V_CC
0.2×V_CC
V
V_CC
V
1. The parasitic capacitance from the package and board may be estimated to be 2pF. The effective load capacitor for the crystal is
(C_XIN x C_XOUT) / (C_XIN + C_XOUT). It is independent of XTS_FLL .
2. To improve EMI on the low-power LFXT1 oscillator, particularly in the LF mode (32 kHz), the following guidelines must be
observed:
• Keep the trace between the MSP430FE42x2 and the crystal as short as possible.
• Design a good ground plane around the oscillator pins.
• Prevent crosstalk from other clock or data lines into oscillator pins XIN and XOUT.
• Avoid running PCB traces underneath or adjacent to XIN an XOUT pins.
• Use assembly materials and praxis to avoid any parasitic load on the oscillator XIN and XOUT pins.
• If conformal coating is used, ensure that it does not induce capacitive/resistive leakage between the oscillator pins.
• Do not route the XOUT line to the JTAG header to support the serial programming adapter as shown in other documentation.
This signal is no longer required for the serial programming adapter.
3. Applies only when using an external logic-level clock source. XTS_FLL must be set. Not applicable when using a crystal or resonator.
4. External capacitance is recommended for precision real-time clock applications (OSCCAPx = 0h).
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