MK3715 LOW COST 3.3 VOLT VCXO Description Features The MK3715 is a low cost, low jitter, high-performance 3.3 volt VCXO designed to replace expensive VCXO modules. The on-chip Voltage Controlled Crystal Oscillator accepts a 0 to 3.3 V input voltage to cause the output clocks to vary by ±100 ppm. Using ICS’ patented VCXO techniques, the device uses an inexpensive external 13.5 MHz pullable crystal to produce two fixed clock outputs of 54.0 MHz and 108.0 MHz. • Packaged in 8 pin SOIC • 3.3 V only operating voltage • Provides two fixed clock outputs of 54.0 MHzand ICS manufactures a large variety of Set-Top Box and multimedia clock synthesizers for all applications. If more clock outputs are needed, see the MK2731 or MK377x family of parts. Consult ICS to eliminate VCXOs, crystals and oscillators from your board. • VCXO tuning voltage of 0 to 3.3 V • 12mA output drive capability at TTL levels • Advanced, low power, sub-micron CMOS process 108.0 MHz • Uses an inexpensive pullable 13.5 MHz externalcrystal • On-chip VCXO (patented) with pull range of200ppm (minimum) Block Diagram VIN 13.5 MHz Pullable Crystal X1 Voltage Controlled Crystal Oscillator X2 108.0 MHz 1 MDS 3715 B I n t e gra te d C i r c u i t S y s t e m s 54.0 MHz PLL and Multiplier ● 525 Race Stre et, San Jo se, CA 9 5126 Revision 021804 ● te l (40 8) 2 97-12 01 ● w w w. i c st . c o m MK3715 LOW COST 3.3 VOLT VCXO Pin Assignment X1 1 8 X2 VDD 2 7 108M VI N 3 6 54M GND 4 5 VDD 8 - P i n ( 1 5 0 mi l ) S OI C Pin Descriptions Pin Number Pin Name Pin Type 1 XI Input Crystal connection. Connect to a pullable 13.5 MHz crystal. 2 VDD Power Connect to +3.3 V. 3 VIN Input Voltage input to VCXO. Zero to 3.3 V analog input which controls the VCXO frequency. 4 GND Power Connect to ground. 5 VDD Power Connect to +3.3 V. 6 54M Output Fixed clock output of 54.0 MHz. 7 108M Output Fixed clock output of 108.0 MHz. 8 X2 Input Crystal connection. Connect to a pullable 13.5 MHz crystal. 2 MDS 3715 B In te grated Circuit Systems Pin Description ● 525 Ra ce Street, San Jose, CA 9512 6 Revision 021804 ● tel (4 08) 297-1 201 ● w w w. i c s t . c o m MK3715 LOW COST 3.3 VOLT VCXO External Component Selection The MK3715 requires a minimum number of external components for proper operation. Decoupling Capacitors A decoupling capacitor of 0.01µF should be connected between VDD and GND on pins 2 and 4 as close to the MK3715 as possible. For optimum device performance, the decoupling capacitor should be mounted on the component side of the PCB. Avoid the use of vias in the decoupling circuit. Recommended Crystal Parameters: Initial Accuracy at 25°C Drift Over Temperature and Aging Load Capacitance C0/C1 Ratio Equivalent Series Resistance ±20 ppm ±50 ppm 14 pf 240 Max 35 Ω Max The external crystal must be connected as close to the chip as possible and should be on the same side of the PCB as the MK3715. There should be no via’s between the crystal pins and the X1 and X2 device pins. There should be no signal traces underneath or close to the crystal. See application note MAN05. Series Termination Resistor When the PCB trace between the clock output and the load is over 1 inch, series termination should be used. To series terminate a 50Ω trace (a commonly used trace impedance), place a 33Ω resistor in series with the clock line, as close to the clock output pin as possible. The nominal impedance of the clock output is 20Ω. Quartz Crystal The MK3715 VCXO function consists of the external crystal and the integrated VCXO oscillator circuit. To assure the best system performance (frequency pull range) and reliability, a crystal device with the recommended parameters (shown below) must be used, and the layout guidelines discussed in the following section shown must be followed. Crystal Tuning Load Capacitors The crystal traces should include pads for small fixed capacitors, one between X1 and ground, and another between X2 and ground. Stuffing of these capacitors on the PCB is optional. The need for these capacitors is determined at system prototype evaluation, and is influenced by the particular crystal used (manufacture and frequency) and by PCB layout. The typical required capacitor value is 1 to 4 pF. The procedure for determining the value of these capacitors can be found in application note MAN05. The oscillation frequency of a quartz crystal is determined by its “cut” and by the load capacitors connected to it. The MK3715 incorporates on-chip variable load capacitors that “pull” (change) the frequency of the crystal. The crystal specified for use with the MK3715 is designed to have zero frequency error when the total of on-chip + stray capacitance is 14 pF. 3 MDS 3715 B In te grated Circuit Systems ● 525 Ra ce Street, San Jose, CA 9512 6 Revision 021804 ● tel (4 08) 297-1 201 ● w w w. i c s t . c o m MK3715 LOW COST 3.3 VOLT VCXO Absolute Maximum Ratings Stresses above the ratings listed below can cause permanent damage to the MK3715. These ratings, which are standard values for ICS commercially rated parts, are stress ratings only. Functional operation of the device at these or any other conditions above those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods can affect product reliability. Electrical parameters are guaranteed only over the recommended operating temperature range. Item Rating Supply Voltage, VDD 7V All Inputs and Outputs -0.5 V to VDD+0.5 V Ambient Operating Temperature 0 to +70°C Storage Temperature -65 to +150°C Soldering Temperature 260°C Recommended Operation Conditions Parameter Ambient Operating Temperature Power Supply Voltage (measured in respect to GND) Min. Typ. Max. Units 0 – +70 °C +3.45 V +3.15 Reference crystal parameters Refer to page 3 Thermal Characteristics Parameter Thermal Resistance Junction to Ambient Thermal Resistance Junction to Case Conditions Min. Typ. Max. Units θJA Still air 150 °C/W θJA 1 m/s air flow 140 °C/W θJA 3 m/s air flow 120 °C/W 40 °C/W θJC 4 MDS 3715 B In te grated Circuit Systems Symbol ● 525 Ra ce Street, San Jose, CA 9512 6 Revision 021804 ● tel (4 08) 297-1 201 ● w w w. i c s t . c o m MK3715 LOW COST 3.3 VOLT VCXO DC Electrical Characteristics VDD=3.3 V ±5% , Ambient temperature 0 to +70°C, unless stated otherwise Parameter Symbol Conditions Operating Voltage VDD Output High Voltage VOH IOH = -12 mA Output Low Voltage VOL IOL = 12 mA Output High Voltage (CMOS Level) VOH IOH = -4 mA Operating Supply Current IDD No load Short Circuit Current IOS VIN, VCXO Control Voltage VIA Min. Typ. Max. Units 3.45 V 3.15 2.4 V 0.4 VDD-0.4 V V 6 mA ±50 mA 0 3.3 V AC Electrical Characteristics VDD = 3.3 V ±5%, Ambient Temperature 0 to +70° C, unless stated otherwise Parameter Symbol Conditions Min. Input Crystal Frequency Typ. Max. Units 13.500000 Input Crystal Accuracy MHz Note 1 Output Frequency Pullability FP 0V< VIN < 3.3 V, Note 1 Output Clock Rise Time tOR 0.8 to 2.0 V 1.5 ns Output Clock Fall Time tOF 2.0 to 0.8 V 1.5 ns Output Clock Duty Cycle tD At VDD/2 60 % Maximum Absolute Jitter, short term tJ +100 40 ppm 50 110 ps Note 1: External crystal device must conform with Pullable Crystal Specifications listed on page 3. 5 MDS 3715 B In te grated Circuit Systems ● 525 Ra ce Street, San Jose, CA 9512 6 Revision 021804 ● tel (4 08) 297-1 201 ● w w w. i c s t . c o m MK3715 LOW COST 3.3 VOLT VCXO Package Outline and Package Dimensions (8-pin SOIC) Package dimensions are kept current with JEDEC Publication No. 95 Index Area E H Pin 1 h x 45 0 D Symbol Millimeters Min Max Inches Min Max A A1 B C D E e H h L a 1.35 1.75 0.10 0.25 0.33 0.51 0.19 0.25 4.80 5.00 3.80 4.00 1.27 Basic 5.80 6.20 0.25 0.50 0.40 1.27 0° 8° 0.0532 0.0688 0.0040 0.0098 0.013 0.020 0.0075 0.0098 .1890 .1968 0.1497 0.1574 0.050 Basic 0.2284 0.2440 0.010 0.020 0.016 0.050 0° 8° A Q c e b Ordering Information Part / Order Number Marking Shipping packaging Package Temperature MK3715S MK3715STR 3715S 3715S Tubes Tape and Reel 8-pin SOIC 8-pin SOIC 0 to +70° C 0 to +70° C While the information presented herein has been checked for both accuracy and reliability, Integrated Circuit Systems (ICS) assumes no responsibility for either its use or for the infringement of any patents or other rights of third parties, which would result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in normal commercial applications. Any other applications such as those requiring extended temperature range, high reliability, or other extraordinary environmental requirements are not recommended without additional processing by ICS. ICS reserves the right to change any circuitry or specifications without notice. ICS does not authorize or warrant any ICS product for use in life support devices or critical medical instruments. 6 MDS 3715 B In te grated Circuit Systems ● 525 Ra ce Street, San Jose, CA 9512 6 Revision 021804 ● tel (4 08) 297-1 201 ● w w w. i c s t . c o m