We are pleased to introduce you to our crystal unit
· Items to Confirm (designing of oscillation circuit)
· Selection Guidance for crystal unit
· Crystal Products Lineup
· Oscillation Circuit and Selection Guidance of Crystal Unit.
· Precautions for designing of PCB Board
Crystal Recommendations for NXP Semiconductors “i.MX 6 Families”.
· Recommendations i.MX 6 Family.
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.
* frequency stability: frequency deviation out of circuit conditions.
When Customer selects crystal unit, ｌload 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
SM146
7×1.5×1.4t
DSC, Consumer equipment, Radio equipment, Blood pressure meter, Blood-sugar monitor, Security systems
S3215
3.2×1.5×0.8t
PMP, DSC, Portable equipment
S3215
3.2×1.5×0.9t
Automotive accessories and ECU sub clock
S3225
3.2×2.5×0.7t
-Mobile phone,Bluetooth,W-LAN
-ISM band,Clock for MPU
i.MX 6Quad, 6Dual, 6DualLite, 6Solo
Pin number of RTC_XTALI/RTC_XTALO
21x21mm BGA
RTC_XTALI
RTC_XTALO
All Families
D9
C9
IC
name
Product
name
Freq.
[kHz]
CL*1
[pF]
f_tol *2
[ppm]
Product
Code*3
External
parts *4
Package
size[mm]
WxDxH
Cg
[pF]
Cd
[pF]
Rf
[Ω]
MCIMX6U5DVM10x
S3215
32.768
7.0
20
S3215-32.768K-7-20-E
10
10
-
3.2x1.5x0.8
MCIMX6D5EYM10x
SM146
12.5
20
SM146-32.768K-12.5-20-E
22
22
10M
7.0x1.5x1.4
MCIMX6S6AVM08x
S3215
9.0
20
S3215-32.768K-9-20-E
18
18
10M
3.2x1.5x0.9
Pin number of XTALI/XTALO
21x21mm BGA
XTALI
XTALO
All Families
A7
B7
IC
name
Product
name
Freq.
[MHz]
CL*1
[pF]
f_tol *2
[ppm]
Product
Code
External
parts *3
Package
size[mm]
WxDxH
Cg
[pF]
Cd
[pF]
Rf
[Ω]
MCIMX6S6AVM08x
S3225
24
10.0
20
S3225-24.000M-10-20-30-E
5
5
-
3.2x2.5x0.7
MCIMX6Q6AVT10x
30
S3225-24.000M-10-30-30-A
7
7
-
MCIMX6D6AVT10x
7
7
-
MCIMX6S6AVM08x
7
7
1M
Notes:*
1. Load capacitance.
2. Frequency tolerance (standard)
3. 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.
4. Please evaluate a crystal oscillator without an external feedback resistor Rf if you need. It is possible that a crystal oscillator works without it because i.MX 6 series has an internal feedback resistor Rf in the MHz oscillator.
-Please lay out crystal unit, capacitor and resistor near i.MX 6 as far as possible.
-The length of signal patterns in oscillation circuit should be as short as possible, and do not cross other signal lines.
For 32kHZ Crystal Unit
-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.
