Clock Crystal Oscillators Surface Mount Type K53-1C Series CMOS / 1.8V / 7.0×5.0A Features How to Order • Miniature ceramic package • Highly reliable with seam welding • CMOS output • Supply voltage VDD=1.8V • ±25ppm, ±20ppm available K53-1C 0 - S E 25.0000 q Table 1 Stability TOPR (°C) Code (ppm) 0 ± 50 S ± 30 −10 to +70 (STD) U ± 25 W ± 20 F ±100 −40 to +85 G ± 50 (Extend) RoHS Conforming Pb Free w er t qType(7×5 SMD, 1.8V) wFrequency Stability Code(See Table1) eDuty Ratio(S: 45% to 55% STD) rEnable/Disable Function(STD) tOscillation Frequency(Ex.: 25.0000MHz) Note Standard specifications Packaging(Tape & Reel 1Kpcs/reel) With only certain frequencies With only certain frequencies Specifications Item Output Frequency Range Symbol FOUT Frequency Stability FSBY Storage Temperature Range TSTG Operating Temperature Range TOPR Conditions Min. 1.8 −20 −25 −30 −50 −55 −10 −40 −0.5 1.75 1.71 ------------45 Max. 39.99 +20 +25 +30 +50 +125 +70 +85 3.6 1.85 1.89 3 4 10 55 Units MHz ----- 9 nS ----90% VDD ----0 ----70% VDD ------------- 10% VDD ----15 VDD 30% VDD ----150 5 10 Overall conditions: initial tolerance, operating temperature range, rated power supply voltage change, load change, aging(1year @25°C), shock and vibration Standard Extend(option) ----- Max. Supply Voltage Supply Voltage Stability: ±50ppm, ±30ppm, ±100ppm(Ext Temp) Stability: ±20ppm, ±25ppm, ± 50ppm(Ext Temp) 1.8≤FOUT≤25MHz 25<FOUT≤39.99MHz Standby Function @50% VDD VDD Current Consumption (Maximum Loaded) Standby Current Duty Ratio(Symmetry) Rise/Fall Time (10% VDD to 90% VDD Maximum Loaded) Output Voltage-"L" Output Voltage-"H" Output Load Input Voltage Range Input Voltage-"L" Input Voltage-"H" Output Disable Time Output Enable Time Start-up Time IDD IST SYM Tr/Tf IOL=2.8mA IOH=−2.8mA CMOS VOL VOH CL VIN VIL VIH --------ST @Minimum operating Voltage to be 0sec. ppm °C Volt mA µA % Volt pF Volt Volt nS mS mS Note: Please contact us for inquires about extended operating temperature range, available frequencies and other conditions. All electrical characteristics are defined at the maximum load and operating temperature range. Dimensions 7.0 1.4 0.8 Recommended Land Pattern (Unit : mm) 0.1 (Unit : mm) 5.08 0.76 q 1.6 5.08 Pin Connections q Control w Case GND e Output r VDD Enable/Disable Function Pad1 Pad3(Output) Open Active "H" Level Active "L" Level High Z(No-Osillation) 4.2 w Plating: Ni+Au Tolerance: ±0.2 2.0 r 2.6 1.2 5.0 e 1.8 Note: A capacitor of value 0.01µF between VDD and GND is recommended. Clock Crystal Oscillators Surface Mount Type K53-2C Series CMOS / 2.5V / 7.0×5.0A Features How to Order • Miniature ceramic package • Highly reliable with seam welding • CMOS output • Supply voltage VDD=2.5V • ±25ppm, ±20ppm available K53-2C 0 - S E 25.0000 q RoHS Conforming Pb Free er t qType(7×5 SMD, 2.5V) wFrequency Stability Code(See Table1) eDuty Ratio(S: 45% to 55% STD) rEnable/Disable Function(STD) tOscillation Frequency(Ex.: 25.0000MHz) Table 1 Stability TOPR (°C) Code (ppm) 0 ± 50 S ± 30 −10 to +70 (STD) U ± 25 W ± 20 F ±100 −40 to +85 G ± 50 (Extend) w Note Standard specifications Packaging(Tape & Reel 1Kpcs/reel) With only certain frequencies With only certain frequencies Specifications Item Output Frequency Range Symbol FOUT Frequency Stability FSBY Storage Temperature Range TSTG Operating Temperature Range TOPR Conditions Overall conditions: initial tolerance, operating temperature range, rated power supply voltage change, load change, aging(1year @25°C), shock and vibration Standard Extend(option) ----- Max. Supply Voltage Supply Voltage VDD Current Consumption (Maximum Loaded) IDD Standby Current Duty Ratio(Symmetry) Rise/Fall Time (10% VDD to 90% VDD Maximum Loaded) Output Voltage-"L" Output Voltage-"H" Output Load Input Voltage Range Input Voltage-"L" Input Voltage-"H" Output Disable Time Output Enable Time Start-up Time Stability: ±50ppm, ±30ppm, ±100ppm(Ext Temp) Stability: ±20ppm, ±25ppm, ± 50ppm(Ext Temp) 1.8≤FOUT≤20MHz 20<FOUT≤40MHz 40<FOUT≤67MHz Standby Function @50% VDD 1.8≤FOUT≤40MHz 40<FOUT≤67MHz IOL=4mA(8mA:40MHz<FOUT) IOH=−4mA(−8mA:40MHz<FOUT) CMOS IST SYM Tr/Tf VOL VOH CL VIN VIL VIH --------ST @Minimum operating Voltage to be 0sec. Min. 1.8 −20 −25 −30 −50 −55 −10 −40 −0.5 2.38 2.43 ------------45 ---------90% VDD ---0 ---70% VDD ---------- Max. 67 +20 +25 +30 +50 +125 +70 +85 7.0 2.62 2.57 5 10 15 10 55 7 4 10% VDD ---15 VDD 30% VDD ---150 5 10 Units MHz ppm °C Volt mA µA % nS Volt pF Volt Volt nS mS mS Note: Please contact us for inquires about extended operating temperature range, available frequencies and other conditions. All electrical characteristics are defined at the maximum load and operating temperature range. Dimensions 7.0 1.4 0.8 Recommended Land Pattern (Unit : mm) 0.1 (Unit : mm) 5.08 0.76 q 1.6 5.08 Pin Connections q Control w Case GND e Output r VDD Enable/Disable Function Pad1 Pad3(Output) Open Active "H" Level Active "L" Level High Z(No-Osillation) 4.2 w Plating: Ni+Au Tolerance: ±0.2 2.0 r 2.6 1.2 5.0 e 1.8 Note: A capacitor of value 0.01µF between VDD and GND is recommended. Clock Crystal Oscillators Surface Mount Type K53-3C Series CMOS / 3.3V / 7.0×5.0A Features How to Order • Miniature ceramic package • Highly reliable with seam welding • CMOS output • Supply voltage VDD=3.3V • ±25ppm, ±20ppm available K53-3C 0 - S E 25.0000 q RoHS Conforming Pb Free er t qType(7×5 SMD, 3.3V) wFrequency Stability Code(See Table1) eDuty Ratio(S: 45% to 55% STD) rEnable/Disable Function(STD) tOscillation Frequency(Ex.: 25.0000MHz) Table 1 Stability TOPR (°C) Code (ppm) 0 ± 50 S ± 30 −10 to +70 (STD) U ± 25 W ± 20 F ±100 −40 to +85 (Extend) G ± 50 w Note Standard specifications Packaging(Tape & Reel 1,000pcs/reel) With only certain frequencies With only certain frequencies Specifications Item Output Frequency Range Symbol FOUT Frequency Stability FSBY Storage Temperature Range TSTG Operating Temperature Range TOPR Max. Supply Voltage Conditions Overall conditions: initial tolerance, operating temperature range, rated power supply voltage change, load change, aging(1year @25°C), shock and vibration Standard Extend(option) ----- Supply Voltage VDD Current Consumption (Maximum Loaded) IDD Standby Current Duty Ratio(Symmetry) IST SYM Rise/Fall Time (10% VDD to 90% VDD Maximum Loaded) Tr/Tf Output Voltage-"L" Output Voltage-"H" Output Load Input Voltage Range Input Voltage-"L" Input Voltage-"H" Output Disable Time Output Enable Time Start-up Time VOL VOH CL VIN VIL VIH --------ST Stability: ±50ppm, ±30ppm, ±100ppm(Ext Temp) Stability: ±20ppm, ±25ppm, ± 50ppm(Ext Temp) 1.8≤FOUT≤ 20MHz 20<FOUT≤ 40MHz 40<FOUT≤ 60MHz 60<FOUT≤ 80MHz 80<FOUT≤100MHz 100<FOUT≤135MHz 135<FOUT≤160MHz Standby Function @50% VDD 8≤FOUT≤ 26MHz 26<FOUT≤ 45MHz 45<FOUT≤100MHz 100≤FOUT≤160MHz IOL=8mA IOH=−8mA CMOS @Minimum operating Voltage to be 0sec. Min. 1.8 −20 −25 −30 −50 −55 −10 −40 −0.5 2.97 3.14 ------------------------45 ---------------90% VDD ---0 ---70% VDD ---------- Max. 160 +20 +25 +30 +50 +125 +70 +85 7.0 3.63 3.46 10 15 30 35 40 50 60 10 55 10 8 5 2.5 10% VDD ---15 VDD 30% VDD ---150 5 10 Units MHz ppm °C Volt mA µA % nS Volt pF Volt Volt nS mS mS Note: Please contact us for inquires about extended operating temperature range, available frequencies and other conditions. All electrical characteristics are defined at the maximum load and operating temperature range. Dimensions e r w q 1.6 5.08 5.08 Plating: Ni+Au Tolerance: ±0.2 Pin Connections q Control w Case GND e Output r VDD Enable/Disable Function Pad1 Pad3(Output) Open Active "H" Level Active "L" Level High Z(No-Oscillation) 2.0 0.8 2.6 5.0 0.76 1.2 1.4 (Unit : mm) 4.2 7.0 Recommended Land Pattern 0.1 (Unit : mm) 1.8 Note: A capacitor of value 0.01µF between VDD and GND is recommended. Clock Crystal Oscillators Surface Mount Type K53-HC Series CMOS / 5.0V / 7.0×5.0A Features How to Order • Miniature ceramic package • Highly reliable with seam welding • CMOS output • Supply voltage VDD=5.0V • ±25ppm available K53-HC 0 - C S E 25.0000 q RoHS Conforming Pb Free TOPR (°C) ert y qType(7×5 SMD, 5.0V) wFrequency Stability Code(See Table1) eCMOS Output rDuty Ratio(S: 45% to 55% STD) tEnable/Disable Function(STD) yOscillation Frequency(Ex.: 25.0000MHz) Table 1 Stability Code (ppm) 0 ± 50 S ± 30 U ± 25 F ±100 G ± 50 w Note Standard specifications −10 to +70 With only certain (STD) frequencies Packaging(Tape & Reel 1,000pcs/reel) −40 to +85 With only certain (Extend) frequencies Specifications Item Output Frequency Range Symbol FOUT Frequency Stability FSBY Storage Temperature Range TSTG Operating Temperature Range TOPR Max. Supply Voltage Conditions Overall conditions: initial tolerance, operating temperature range, rated power supply voltage change, load change, aging(1year @25°C), shock and vibration Standard Extend(option) ----- Supply Voltage VDD Current Consumption (Maximum Loaded) IDD Disable Current Duty Ratio(Symmetry) Rise/Fall Time (10% VDD to 90% VDD Maximum Loaded) Output Voltage-"L" Output Voltage-"H" Output Load Input Voltage Range Input Voltage-"L" Input Voltage-"H" Output Disable Time Output Enable Time Start-up Time Stability: ±50ppm, ±30ppm, ±100ppm(Ext Temp) Stability: ±25ppm, ±50ppm(Ext Temp) 1.8≤FOUT≤20MHz 20<FOUT≤40MHz 40<FOUT≤50MHz @50.0000MHz @50% VDD 8≤FOUT≤26MHz 26<FOUT≤50MHz IOL=16mA IOH=−16mA IDE SYM Tr/Tf VOL VOH CL VIN VIL VIH --------ST @Minimum operating Voltage to be 0sec. Min. 1.8 −25 −30 −50 −55 −10 −40 −0.5 4.5 4.75 ----------------45 ------------90% VDD ----0 ----2.2 ------------- Max. 50 +25 +30 +50 +125 +70 +85 7.0 5.5 5.25 25 35 50 30 55 10 8 10% VDD ----50 VDD 0.8 ----100 100 10 Units MHz ppm °C Volt mA mA % nS Volt pF Volt Volt nS nS mS Note: Please contact us for inquires about extended operating temperature range, available frequencies and other conditions. All electrical characteristics are defined at the maximum load and operating temperature range. Dimensions e r w q 5.08 1.6 5.08 Plating:Ni+Au Tolernce:±0.2 Pin Connections q Control w Case GND e Output r VDD Enable/Disable Function Pad1 Pad3(Output) Open Active "H" Level Active "L" Level High Z 2.0 0.8 2.6 5.0 0.76 1.2 1.4 (Unit : mm) 4.2 7.0 Recommended Land Pattern 0.1 (Unit : mm) 1.8 Note: A capacitor of value 0.01µF between VDD and GND is recommended. Handling Notes for Crystal Oscillators 1. Shock & Drop • Vibration 2. Cleaning Do not inflict excessive shock and mechanical vibration that exceeds the norm, such as hitting or mistakenly dropping, when transporting and mounting on a board. There are cases when pieces of crystal break, and pieces that are used become damaged, and become inoperable. When a shock or vibration that exceeds the norm has been inflicted, make sure to check the characteristics. Since a crystal piece can be broken by resonance when a crystal device is cleaned by ultrasonic cleaning. Be careful when carrying out ultrasonic cleaning. 3. Soldering conditions To maintain the product reliability, please follow recommended conditions. Standard soldering iron conditions Crystal Oscillators Soldering iron 280˚C ~ 340˚C Time 3+1/−0sec. max Reflow conditions (Example) +0 Peak:260 -10 ˚C Temperature(˚C) 10sec. max +0 180 -10 ˚C 200˚C min 40sec. max 120sec. max Time(sec.) Crystal Oscillators/TCXOs Recommended reflow Conditions vary depending upon products. Please check with the respective specification for details. 4. Mounting Precautions Leaded Devices The special glass, located where the lead of the retainer base comes out, is aligned with the coefficient of thermal expansion of the lead, If the glass is damaged and cracks appear, there may be cases in which performance deteriorates and it fails to operate. Consequently, when making the device adhere closely and applying solder, align the gap of the hole of the board with the gap of the lead and insert without excessive force. When making the device adhere closely to a through hole board and applying solder, be careful that the solder does not get into the metal part of the retainer base and cause a short. Putting in an insulation spacer is one more method of preventing a short circuit. When the lead is mounted floating, fix it as far as possible so that contact with other parts and the breakage due to the fatigue, and the mechanical resonance of the lead will not occur. When the lead is bent and used, do not bend the lead directly from the base, separate it 0.5mm or more and then bend it. When bending, before attaching to the board, fix the place where the lead comes out in advance and attach it after bending so that a crack does not occur in the glass part. Surface Mount Devices The lead of the device and the pattern of the board is soldered on the surface. Since extreme deformation of the board tears off the pattern, tears off the lead metal, cracks the solder and damages the sealed part of the device and there are cases in which performance deteriorates and operation fails, use it within the stipulated bending conditions. Due to the small cracks in the board resulting from mounting, please pay sufficient attention when attaching a device at the position where the warping of the board is great. When using an automatic loading machine, as far as possible, select a type that has a small impact and use it while confirming that there is no damage. Surface mount devices are NOT flow soldering compatible. 5. Storage Condition Since the long hour high temperature and low temperature storage, as well as the storage at high humidity are causes of deterioration in frequency accuracy and solderability. Parts should be stored in temperature range of -5 to +40C˚, humidity 40 to 60% RH, and avoid direct sunlight. Then use within 6 months. Handling Notes for Crystal Oscillators 6. In order to use crystal oscillators (1)The minlature crystal oscillator for the clock utillzes a C-MOS IC and incorporates a protective circuit against static electricity However, exerclse care in the same manner as for a normal C−MOS IC. (2)Internal capacitor is not provided in the power supply section (+DC−GNC). To serve as overimpressed voltage and overcurrent protective device, place a bypass capacitor (0.01 µF) as near as possible to the (+DC−GND) terminal. However, the capacity value is meant as a guideline. Depending on the capacitor type, frequency characteristics vary. Accordingly, use a capacitor that matches the frequency characteristics. (3)Applying reverse voltage could result in damage to internal parts. Take care not to connect terminals incorrectly. (4)Please do not use oscillators under unfavorable condition such as beyond specified range in catalog or specification sheet. (5)Please keep oscillators away from water, salt water or harmful gas. (6)K50H-3C / FSO series should be stored in humidity-controlled area after the package is unsealed, in temperature +25±5˚C under humidity of 65%RH, and should be mounted on PCB within 7 days. (7)K50H-3C / FSO series has Bypass Capacitior between VDD and GND. Test Circuits and Clock Timing Chart CMOS Output Test Circuits Clock Timing chart(C-MOS Output) Note) Maximum load(Includes capacitances of fixture and probe) LV-PECL Output Test Circuits Clock Timing chart (LV-PECL Output) Tape & Reel Specifications Tape & Reel Specifications ICrystal Oscillators KC2520 K25 K30 FXO-61F FXO-64F VC-FXO-65F A 2.0±0.1 2.0±0.1 2.0±0.1 2.0±0.1 B 4.0±0.1 4.0±0.1 4.0±0.1 4.0±0.1 φ1.5+0.1/−0 φ1.55±0.1 8.0±0.1 C T A P E R E E L D 4.0±0.1 8.0±0.1 8.0±0.1 E 3.5±0.05 3.5±0.05 5.5±0.1 5.5±0.1 F 1.75±0.1 1.75±0.1 1.75±0.1 1.75±0.1 G 8.0±0.2 8.0±0.2 12.0±0.2 12.0±0.3 H φ1.1±0.1 φ1.55±0.1 φ1.55±0.1 φ1.55±0.1 J 2.7±0.1 3.5±0.05 5.5±0.1 5.4±0.1 L 2.2±0.1 2.8±0.05 3.7±0.1 3.6±0.1 N 1.25±0.1 1.1±0.05 1.4±0.1 1.7±0.1 O 0.2±0.05 0.3±0.05 0.3±0.05 0.3±0.05 P φ180+0/−3 φ180+0/−3 φ180+0/−3 φ254±2 Q φ60+1/−0 φ60+1/−0 φ60+1/−0 φ100±1 R φ13±0.2 φ13±0.2 φ13±0.2 φ13±0.5 φ21±0.8 S φ21±0.8 φ21±0.8 φ21±0.8 U 2.0±0.5 2.0±0.5 2.0±0.5 2.0±0.5 W 9.0±0.3 9.0±0.3 13.0±0.3 13.4+2/-0 2000 2000 1000 1000 FSO-1C/1D FSO-2B/2C/2D VC-FSO-1D FXO-31F FXO-34F FXO-37F VC-FXO-35F VCXO-7050 K50H K50 K53 K50V-3P KT21 2.0±0.1 2.0±0.1 2.0±0.1 2.0±0.1 Qty A T A P E (VC)TCXO-214C (VC)TCXO-212C 2.0±0.1 2.0±0.1 (VC)TCXO-208C MFO-208F KT18B KT20A (VC)TCXO-204C 2.0±0.1 2.0±0.1 2.0±0.1 2.0±0.1 B 4.0±0.1 4.0±0.1 4.0±0.1 4.0±0.1 4.0±0.1 4.0±0.1 4.0±0.1 4.0±0.1 4.0±0.1 4.0±0.1 C φ1.55±0.1 φ1.55±0.1 φ1.5±0.1 φ1.5+0.1/−0 φ1.5+0.1/−0 φ1.5+0.1/−0 φ1.5+0.1/−0 φ1.5+0.1/−0 φ1.5+0.1/−0 φ1.5+0.1/−0 D 8.0±0.1 8.0±0.1 8.0±0.1 4.0±0.1 4.0±0.1 4.0±0.1 8.0±0.1 4.0±0.1 E 7.5±0.1 7.5±0.1 7.5±0.1 3.5±0.1 3.5±0.05 5.5±0.1 5.5±0.1 5.5±0.1 5.5±0.1 7.5±0.1 1.75±0.1 8.0±0.1/4.0±0.1 8.0±0.1/4.0±0.1 F 1.75±0.1 1.75±0.1 1.75±0.1 1.75±0.1 1.75±0.1 1.75±0.1 1.75±0.1 1.75±0.1 1.75±0.1 G 16.0±0.3 16.0±0.3 16.0±0.2 8.0±0.3 8.0±0.2 8.0±0.3/12.0±0.3 12.0±0.3 12.0±0.3 12.0±0.3 16.0±0.3 H φ1.55 φ1.55 φ1.55±0.1 φ1.5+0.1/−0 φ1.0+0.2/−0 φ1.5+0.1/−0 φ1.5+0.1/−0 φ1.5+0.1/−0 φ1.5+0.1/−0 φ1.5+0.1/−0 J 8.18 8.18 7.4±0.1 3.5±0.1 3.6±0.1 4.4±0.1 5.5±0.1 5.5±0.1 5.5±0.1 7.4±0.1 3.7±0.1 3.7±0.1 3.7±0.1 5.4±0.1 L 5.56 5.56 5.4±0.1 2.8±0.1 2.9±0.1 2.9±0.1 N 2.16±0.1 2.16±0.1 2.0±0.1 1.1±0.1 1.3±0.1 1.1±0.1/1.3±0.1 O 0.3±0.05 0.3±0.05 0.3±0.05 0.25±0.05 0.3±0.05 0.2±0.05/0.3±0.05 0.3±0.05 φ180+0/-3 φ180±2 φ180+1/−1.5 φ254±1/φ180+1/−1.5 P R E E L φ1.5+0.1/−0 φ1.5+0.1/−0 Feed direction φ330±2φ254±2 φ330±2φ254±2 1.8±0.1 2.1±0.1 0.3±0.05 0.3±0.05 0.3±0.05 φ330±1 φ330±1 φ330±1 φ254±2 1.6±0.1/1.5±0.1 1.6±0.1/1.5±0.1 Q φ100±1 φ100±1 φ60+1/−0 φ60 φ60+1/−0 φ100±1/φ60+1/−0 φ100±1/φ60 φ100±1φ60 φ100±1 φ100±1 R φ13±0.3 φ13±0.3 φ13±0.2 φ13±0.2 φ13±0.2 φ13±0.2 φ13±0.2 φ13±0.2 φ13±0.2 φ13±0.2 S φ21±0.8 φ21±0.8 φ21±0.8 φ21±0.8 φ21±0.8 φ21±0.8 φ21±0.8 φ21±0.8 φ21±0.8 φ21±0.8 U 2.0±0.5 2.0±0.5 2.0±0.5 2.0±0.5 2.0±0.5 2.0±0.5 2.0±0.5 2.0±0.5 2.0±0.2 2.0±0.5 16.4 17.5±0.5/16.4 17±0.2 9.0±0.1 9.0+0.3/−0 9.0±0.3/13.0+0.3−0 13.5±1 13.5±1 13.5±1 17.5±0.5 3000/1000 3000/1000 1000 2000 2000 4000/2000 2000 4000 4000 1000 W Qty Ordering Format for Crystal Oscillatiors ORDERING FORMAT FOR CRYSTAL OSCILLATORS Please specify the following items when ordering crystal oscillators. I. Standard products shown in the catalogue: Please specify package type and nominal frequency. II. Special-order products: Please specify the following items in specification. 1 . Frequency (1)Oscillation Frequency ____________ Hz 2 . Frequency Stability (1)Temperature ______ ×10-6 MAX. ______ ~ ______˚C (On the basis of +25˚C frequency) (2)Supply Voltage ______ ×10-6 MAX. ______ VDC ± ______ % (3)Load. ______ ×10-6 MAX. ______ Ω// ______ pF ± ______ % ± ______ % (4)Aging ______ ×10-6 MAX./year 3 . Frequency Tuning Range ± ______ ×10-6 MIN 4 . Frequency Control Range ± ______ ~± ______ ×10-6 /+ ______ V± ______ V 5 . Output (1)Voltage ______ Vrms ______ VP-P MIN. (2)Wave Form Sine, Half sine wave, Harmonics 2nd ______ dB, 3rd ______ dB, Others ______ dB (3)Load Resistance ______ Ω//Capacitance ______ pF 6 . Supply Voltage (1)For circuit ______ VDC± ______ %, ______ mA MAX. 7 . Environmental Condition (1)Operating Temperature Range ______ ~ ______ ˚C (2)Vibration Total Amplitude ______ mm, Vibration Frequency ______ Hz~ ______ Hz (3)Shock ______________________________________________________ 8 . Dimensions, Pin Connection _______________________________________________ 9 . Application ______________________________________________________________