NC38LF-327

## **Thru-Hole Tuning Fork** 

**Model: NC15LF/NC26LF/NC38LF** 

**RoHS Compliant / pB Free** 

**Rev. 1/13/2012** 

http://www.foxonline.com/need_a_sample.htm 

## **FEATURES** 

- Miniature Packages 

- Low Cost 

- Cold Weld Design 

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•  Long Term Stability N C 1 5 L F<br>•  Tight Tolerance<br>Click to view mounting precautions<br>• PART NUMBER SELECTION Learn More - Internet Required - Internet Required<br>Model  Frequency  Operating<br>Part Number Frequency<br>Number Stability Temperature<br>298LF-Frequency-xxxxx  NC15LF  -0.04 PPM / (∆ºC) [2] -20 ºC~ +60 ºC  32.768 kHz<br>299LF-Frequency-xxxxx  NC26LF  -0.04 PPM / (∆ºC) [2] -20 ºC~ +60 ºC  32.768 kHz<br>300LF-Frequency-xxxxx NC38LF -0.04 PPM / (∆ºC) [2] -20 ºC~ +60 ºC 32.768 kHz<br>• STANDARD SPECIFICATIONS<br>PARAMETERS MAX (unless otherwise noted)<br>Frequency 32.768 kHz<br>Frequency Tolerance @ 25ºC ± 20 PPM<br>Frequency Stability N C 2 6 L F<br>   Temperature Coefficient -0.04 PPM / (∆ºC) [2]<br>Temperature Range<br>Turnover  (TO) +20ºC ~ +30ºC<br>Operating (TOPR) -20ºC ~ +60ºC<br>Storage  (TSTG) -30ºC ~ +70ºC<br>Equivalent Series Resistance (RS)<br>   NC15 / NC26 50 kΩ<br>   NC38 35 kΩ<br>Load Capacitance (Cl) 12.5 pF (Standard)<br>6 pF (Optional)<br>Insulation Resistance @ 100VDC 500 MΩ Min<br>Drive Level 1.0 µW<br>Aging per year ±3 PPM<br>All specifications subject to change without notice.<br>Note: Can should not be soldered to the circuit board or grounded. If securing the can to the board<br>is desired, a rubber adhesive is recommended. N C 3 8 L F<br>Parabolic Temperature Curve<br>T(C)<br>-20 -10 0 10 20 30 40 50 60 70<br>-10<br>-20<br>-30<br>-40<br>-50<br>-60<br>A fif (PPM)<br>To determine frequency stability, use parabolic curvature (K).<br>For example: What is stability at 45C?<br>1) Change in T (°C) = 45-25 = 20<br>2) Change in frequency = -0.04 PPM * (acy<br>= -0.04 PPM * (20)<br>= -16.0 PPM<br>All dimensions are in millimeters.<br>1.5 Max<br>5.0 Max<br>0.22 ±0.05<br>4.5 Min<br>0.45<br>2.0 Max<br>6.0 Max<br>0.2 ±0.07<br>4.0 Min<br>0.7 ±0.15<br>3.2 Max<br>8.3 Max<br>0.38±0.05<br>9.0 Min<br>0.8 ±0.1<br>**----- End of picture text -----**<br>


- Long Term Stability 

- Tight Tolerance 

- **PART NUMBER SELECTION** Learn More - Internet Required - Internet Required 

All specifications subject to change without notice. 

Note: Can should not be soldered to the circuit board or grounded. If securing the can to the board is desired, a rubber adhesive is recommended. 

**FOX** Electronics  5570 Enterprise Parkway   Fort Myers, Florida  33905  USA   +1.239.693.0099   FAX +1.239.693.1554 www.foxonline.com **EMEA** Tel: +44 .1283.568153 | **Canada** +1.888.438.2369 | **Asia** Hong Kong Tel: +852.2854.4285 | **Japan** Tel: +81.3.3374.2079 © 2012  FOX ELECTRONICS | ISO9001:2008 Certified 

## **1. Mounting Precautions** 

## **1.1 Lead Type Crystal Units** 

## 1.1.1. Structure 

Tubular crystal units are hermetically sealed using glass (see Figures 1 and 2). 

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Case<br>~~<br>Hermetic<br>Glass<br>+_ Lead<br>Figure 1<br>**----- End of picture text -----**<br>


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Case<br>Lead  \ ™ Hermetic<br>Glass<br>Figure 2<br>**----- End of picture text -----**<br>


## 1.1.2 Unbending the lead 

- (1) DO NOT pull the lead excessively if unbending a lead or removing a crystal unit. The excessive force may crack the glass and reduce the degree of vacuum. This may eventually result in deterioration of the characteristics and may also break the crystal chip see Figure 3). 

- (2) Unbend the lead by pressing on the bent part from both the upper and lower sides with fixing the bottom of lead tightly. (see Figure 4). 

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Breakage<br>Pull out<br>/ _».<br>Figure 3<br>**----- End of picture text -----**<br>


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Tweezers or<br>Z needle-nose pliers<br>Case<br>Vv<br>Lead<br>Figure 4<br>**----- End of picture text -----**<br>


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## 1.1.3 Bending the lead 

- (1) Bend the lead so that the lead will remain straight for more than 0.5mm from the case when soldering a crystal unit after bending. If not, the glass may be cracked (see Figures 5 and 6). 

- (2) Always leave a length greater than the case diameter when bending a lead after soldering (see Figure 7). 

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D<br>0.5mm<br>0.5mm<br>L > D<br>Solder<br>Printed circuit<br>board  Solder<br>L<br>Solder<br>Figure 5  Figure 6  Figure 7<br>Soldering directly to the case will reduce the degree of vacuum and may result in  Make the length from the<br>deterioration of the characteristics and may break the crystal chip. case to the printed circuit<br>board (L) longer than the<br>case diameter (D) so that<br>the lead wire will not be<br>pulled in case the crystal<br>unit falls over.<br>**----- End of picture text -----**<br>


## 1.1.4 Soldering 

When mounting or removing a quartz crystal unit, heat the lead part at 300°C or lower for 5 seconds or less (in the case of a lead-type conventional product). A long period of time of heating may result in deterioration of the characteristics and may break the crystal unit. Be sure to keep the case at or below 150°C. 

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