MSP430FE42x2

MIXED SIGNAL MICROCONTROLLER

SLAS616 − JULY 2008

28

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

electrical characteristics over recommended operating free-air temperature (unless otherwise

noted) (continued)

crystal oscillator, LFXT1 oscillator (see Notes 1 and 2)

PARAMETER

TEST CONDITIONS

VCC

MIN

TYP

MAX

UNIT

OSCCAPx = 0h

3 V

0

C

Integrated input capacitance

OSCCAPx = 1h

3 V

10

pF

CXIN

Integrated input capacitance

(see Note 4)

OSCCAPx = 2h

3 V

14

pF

()

OSCCAPx = 3h

3 V

18

OSCCAPx = 0h

3 V

0

C

Integrated output capacitance

OSCCAPx = 1h

3 V

10

pF

CXOUT

Integrated output capacitance

(see Note 4)

OSCCAPx = 2h

3 V

14

pF

OSCCAPx = 3h

3 V

18

VIL

Low-level input voltage at XIN

See Note 3

2 2 V/3 V

VSS

0.2

×VCC

V

VIH

High-level input voltage at XIN

See Note 3

2.2 V/3 V

0.8

×VCC

VCC

V

NOTES:

1. The parasitic capacitance from the package and board may be estimated to be 2pF. The effective load capacitor for the crystal is

(CXIN x CXOUT) / (CXIN + CXOUT). 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).