For customers designing Renesas "RL78/G1D module: RY7011"

We are pleased to introduce you to our crystal unit for RL78/G1D module: RY7011.
Please refer to RL78/G1D Module (RY7011) User’s Manual: Hardware.

Items to Confirm (designing of oscillation circuit)

Please note: to design oscillation circuit, 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.
Please refer to our web site:
http://www5.epsondevice.com/en/information/precaution/design.html

* 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.

Selection Guidance for crystal unit

Epson Crystal Product Lineups

Product Size [mm] Applications Images
FC-12M 2.05 x 1.2 x 0.6t DSC, Consumer equipment,
Radio equipment, Blood pressure meter,
Blood-sugar monitor, Security systems
MC146

Oscillation Circuit and Selection Guidance of Crystal Unit for RL78/G1D module: RY7011

RY7011


Epson Crystal unit External parts *3
Product Frequency
[Hz]
CL *1
[pF]
Part number*2 Cg
[pF]
Cd
[pF]
FC-12M 32.768k 7 X1A000061000600 10 12

Please refer to RL78/G1D Module (RY7011) User’s Manual: Hardware.

Notes:

  • *1 Load Capacitance
  • *2 Two digits of the product code is packing specification, please click here for more detail.
  • *3 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.
    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. Users design must be verified and decided by own and individual evaluation.

Precautions for designing of PCB Board

Layout of pins, Crystal unit, Capacitor and Resistor

-Please lay out crystal unit, capacitor and resistor near RL78/G1D module: RY7011 as far as possible.
-Please connect pins within 20mm length, and do not cross other signal lines.


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