MSP430 Family
For customers designing Texas Instruments
"MSP430 Family" applications
We are pleased to introduce you to our 32.768kHz crystal unit for MSP430 Family.
Items to Confirm (designing of oscillation circuit)
Please note: to design oscillation circuit for MSP430 Family, 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
Drive Level:
You need to confirm if oscillation is stable, and if the drive level is within the specification.
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.
* frequency stability: frequency deviation out of circuit conditions.
Selection Guidance for crystal unit
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.
StrongFirst Crystal Product Lineups
Electronic, Gas, Water meter, Flow meter, Intelligent sensor,
Measurement equipment, Blood pressure meter,
Blood-sugar monitor, Security systems
DSC, Consumer equipment, Radio equipment, Blood pressure meter,
Blood-sugar monitor, Security systems
PMP, DSC, Portable equipment
Oscillation Circuit and Selection Guidance of Crystal Unit (for each MSP430 Family)
For MSP430 FR5xx series
MSP430 FR5xxx crystal oscillator setting and equivalent crystal CL values
Crystal unit
equivalent CL values
(pF)
32.768 kHz Crystal Product Code
Pin number of LFXIN/ LFXOUT for MSP430 FR58xx,FR59xx
(in RHA and DA: MSP430FR594x and MSP430FR584x devices only)
For MSP430 F5xx series
Pin number of XIN/ XOUT for MSP430F5310,F5309,F5308,F5304
Oscillation Circuit and Selection Guidance of Crystal Unit for MSP430 F5xx/F6xx
Customer can use the crystal unit CG and CD due a result of evaluation of circuit board.
MSP430 F5xx/F6xx crystal oscillator setting and equivalent crystal CL values
XCAPx value
(integrated effective load)
Crystal unit
equivalent CL valuesCL
(pF)
32.768 kHz Crystal Product Code
External capacitors are required
Customer can select crystal products
with external capacitor combination
XCAPx=3
default(12pF typ.)
* Product Code: encoded numbers of crystal specifications
Remarks:
By tuning MSP430F5xx/F6xx XT1DRIVE, oscillation allowance and current consumption will be controlled.
Notes:
Please refer to Texas Instruments MSP430 manual for setting XCAPx and other parameters.
For MSP430 F2xx/F4xx/G2xx/AFE series
Customer can use the crystal unit CG and due to a result of evaluation of circuit board.
MSP430 F2xx/F4xx/G2xx/AFE series crystal oscillator setting and equivalent crystal CL values
XCAPx value
(integrated effective load)
Crystal unit
equivalent CL values
(pF)
32.768 kHz Crystal Product Code
External capacitors are required
Customer can select crystal products
with external capacitor combination.
XCAPx=3
default
(11pF typ.)
* Product Code: encoded numbers of crystal specifications
Recommended Crystal CL values and MSP430 F2xx/F4xx/G2xx/AFE XCAPx setting
XCAP value
(integrated effective load typ.)
Higher current consumption,
slower oscillation startup.
Lower stability due to load capacitance variation of
external components and the layout.
For customer required to follow XOSC8 Guidance, crystal products with high ESR are available. here
Texas Instruments Application Report XOSC8 Guidance
Notes:
Please refer to Texas Instruments MSP430 manual for setting XCAPx and other parameters.
* Product Code: encoded numbers of crystal specifications
For MSP430 F1xx series
Recommendation for MSP430 F1xx series
Crystal unit equivalent CL values
(pF)
32.768 kHz Crystal Product Code
Notes
1. Above recommendations are based on actual evaluation results and intended to support users in picking the right components. And the results are only according to the sample set that received from our customers, so it is not including the dispersion trend of IC and the external parts.
2. As the actual board layout and choice of external components influences the best suitable crystal load capacitance, We do not assume any responsibility and grant warranty for above recommendations.
3. Users design must be verified and decided by own and individual evaluation.
Precautions for designing of PCB Board
Layout of XIN, XOUT, Crystal unit, Capacitor and Resistor
-Please lay out crystal unit, capacitor and resistor near MSP430 as far as possible.
-Please connect XIN and XOUT within 20 mm length, and do not cross other signal lines.
For 32kHz crystal unit
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 multi-layered PCB board, do not lay out other signal lines under crystal unit.
Crystal Products for Texas Instruments Application Report XOSC8 Guidance
Customer can select 32.768 kHz Crystal Products from table below.
Crystal unit equivalent CL values
(pF)
32.768 kHz Crystal Product Code
* Product Code: encoded numbers of crystal specifications