Epson Quartz Crystal Devices | For customers designing Texas Instruments "CC430 series" applications

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We are pleased to introduce you to our 32.768 kHz crystal unit for F5xx, and F6xx:

	Items to Confirm (designing of oscillation circuit)
	Selection Guidance for crystal unit
	Crystal Products Lineup
	Oscillation Circuit and Selection Guidance of Crystal Unit (for each CC430 series)
	Precautions for designing of PCB Board

Crystal Recommendations for Texas Instruments "MSP430 series family”.

	Recommendations CC430 F5xx family.
	Recommendations CC430 F6xx family.

For product information of "CC430 series",
please see Texas Instruments' web site.

Please note: to design oscillation circuit for CC430 series, you need to confirm the electronic
characteristics as follows:

Oscillation allowance and Negative resistance (-R):

You need to confirm oscillation capability.
We recommend the condition: (-R) / ESR > 5
* -R: Negative resistance, ESR: Equivalent Series Resistance
Please refer to our web site:
http://www.epsontoyocom.co.jp/english/C_support/precautions/precautions_1.html
Support information > Precautions in Designing oscillation circuits > 2. Allowance for oscillation

Drive Level:

You need to confirm if oscillation is stable, and if the drive level is within the specification.
Please refer to our web site:
http://www.epsontoyocom.co.jp/english/C_support/precautions/precautions_1.html
Support information > Precautions in Designing oscillation circuits > 1. Drive level

Load Capacitance:

Load capacitance affects frequency stability, oscillation allowance, negative resistance, and start-up time of oscillation.
In addition the load capacitance is determinative factor of crystal unit's load capacitance (CL value) directly.
Please refer to our web site:
http://www.epsontoyocom.co.jp/english/C_support/precautions/precautions_2.html
Support information > Precautions in Designing oscillation circuits > 3. Load capacitance

* frequency stability: frequency deviation out of circuit conditions.

When Customer selects crystal　unit,　ｌoad capacitance (CL value) is an important factor of the selection.
For instance, crystal with small CL(7.0 pF) makes larger oscillation allowance, smaller current consumption and worse frequency stability, like below table.
Oppositely, crystal with large CL(12.5 pF) makes smaller oscillation allowance, larger current consumption and better frequency stability.
Please select it in consideration of these characteristics.

Product	Size [mm]	Applications	Images
MC-306	8×3.8×2.5t	Electronic, Gas, Water meter, Flow meter, Intelligent sensor, Measurement equipment, Blood pressure meter, Blood-sugar monitor, Security systems
MC-146	7×1.5×1.4t	DSC, Consumer equipment, Radio equipment, Blood pressure meter, Blood-sugar monitor, Security systems
FC-135 FC-13F	3.2×1.5×0.8t 3.2×1.5×0.55t	PMP, DSC, Portable equipment
FC-12M	2.0×1.2×0.6t	Portable equipment

CC430 F5137,F6137 crystal oscillator setting and equivalent crystal CL values
Please refer TI WEB site for other products

XCAPx value (integrated effective load.)	Crystal unit equivalent CL values	32.768 kHz Crystal Product Code
XCAPx value (integrated effective load.)	Crystal unit equivalent CL values	CL (pF)	MC-306	MC-146	FC-135
XCAPx=0 (2pF Typ.)	External capacitors are required	---	Customer can select crystal products with external capacitor combination.
XCAPx=1 　　　　　 (5.5pF typ)	7 pF	7	Q13MC30610004	Q13MC14610001	Q13FC13500002
XCAPx=2 　　　　　 (8.5pF typ)	12.5 pF	12.5	Q13MC30610003	Q13MC14610002	Q13FC13500004
XCAPx=3 default (12pF typ)	---		---	---	---

* Product Code: encoded numbers of crystal specifications

Choosing a suitable XCAPx setting of CC430 F5137,F6137

No.	Crystal CL Value	XCAP value (integrated effective load typ.)	Advantage	Drawback
1	12.5 pF	XCAPx=2 (8.5pF)	High frequency stability	Higher current consumption, slower oscillation startup
2	7 pF	XCAPx=1 (5.5pF)	Low current consumption	Lower stability due to load capacitance variation of external components and the layout.

Remarks:

By tuning CC430 XT1DRIVE, oscillation allowance and current consumption will be controlled.

Notes:

Above recommendations are based on actual evaluation results and intended to support users in picking the right components.
As the actual board layout and choice of external components influences the best suitable crystal load capacitance, We does not assume any responsibility and grant warranty for above recommendations.
Users design must be verified and decided by own and individual evaluation.
Please refer to Texas Instruments CC430 manual for setting XCAPx and other parameters.

<Layout of XIN, XOUT, Crystal unit, Capacitor and Resistor>
-Please lay out crystal unit, capacitor and resistor near CC430 as far as possible.
-Please connect XIN and XOUT within 20mm length, and do not cross other signal lines.


	If Vcc drops to below 2.5V, insert a resistor of 5.1 ohms between XOUT and GND.

<GND Line Pattern and Interconnection of PCB>
-Please lay out GND line pattern under crystal unit.
-In case of muli-layered PCB board, do not lay out other signal lines under crystal unit.

Cross-seection View(Multi-layered PCB Board)