MK3711 LOW COST 8 - 16 MHZ 3.3 VOLT VCXO Description The MK3711 series of devices include the original MK3711S, MK3711A, and the new MK3711B and MK3711D. The MK3711D and MK3711B are drop-in replacements for the MK3711S and MK3711A devices. Compared to these earlier devices the MK3711D and MK3711B offer a wider operating frequency range and improved power supply noise rejection. an PWM RC integrator circuit. Frequency output increases with VIN voltage input. The usable range of VIN is 0 to 3V. Features • MK3711D and MK3711B are drop-in replacements for the earlier MK3711S and MK3711A devices The MK3711 series combines the functions of a VCXO (Voltage Controlled Crystal Oscillator) and PLL (Phase Locked Loop) frequency doubler onto a single chip. Used in conjunction with an external pullable quartz crystal, this monolithic integrated circuit replaces more costly hybrid (canned) VCXO devices. The MK3711 is designed primarily for data and clock recovery applications within end products such as ADSL modems, set-top box receivers, and telecom systems. • MK3711D and MK3711B offer 24-36 MHz output The MK3711D exhibits a moderate VCXO gain of 120ppm/V typical, when used with a high quality external pullable quartz crystal. The MK3711B offers a higher VCXO gain of 150ppm/V, similar to the earlier MK3711A. The higher intrinsic VCXO gain of the MK3711C may help compensate for the reduced pullability of a low quality crystal used in some applications. However, higher VCXO gain may also increase clock output phase noise. external pullable crystal to generate lock 27 MHz clock transport video clock The frequency of the on-chip VCXO is adjusted by an external control voltage input into pin VIN. Since VIN is a high impedance input, it can be driven directly from frequency range (output frequency = 2x crystal frequency) and improved power supply noise rejection • Uses an inexpensive 12 to 18 MHz external crystal • Ideal for ADSL applications using 17.664 MHz external pullable crystal to generate locked 35.328 MHz clock physical layer clock • Ideal for set-top box applications using 13.5 MHz • On-chip VCXO with guaranteed pull range of ±115 ppm minimum (MK3711D) • VCXO tuning voltage 0 to 3.3 V • Packaged in 8 pin SOIC (150 mil wide) MK3711D is Recommended for New Designs Block Diagram V D D V IN X 1 8 -1 6 M H z P u lla b le C ry s ta l X 2 V o lta g e C o n tro lle d C ry s ta l O s c illa to r 8 -1 6 M H z G N D 1 MDS 3711 F In tegr ated C ir cu it S yst ems ● 5 25 Ra ce Str eet, San Jose, C A 95 126 Revision 070301 ● tel ( 408) 2 95-9 800 ● www. i c s t. c om MK3711 LOW COST 8 - 16 MHZ 3.3 VOLT VCXO Pin Assignment X1 1 8 X2 VDD VIN 2 3 DC REF GND 4 7 6 5 DC MK3711S MK3711A MK3711B MK3711D 8 Pin (150 mil) SOIC Pin Descriptions Pin Number Pin Name Pin Type 1 XI Input 2 VDD Power 3 VIN Input 4 GND Power 5 DC -- 6 REF Output 7 DC -- 8 X2 Input Crystal connection. Connect to the external pullable crystal. Connect to +3.3 V (0.01uf decoupling capacitor recommended). Voltage input to VCXO -- 0 to 3.3 V analog input which controls the oscillation frequency of the VCXO. Connect to ground. Do not connect anything to this pin. VCXO CMOS level clock output matches the nominal frequency of the crystal. Do not connect anything to this pin. Crystal connection. Connect to the external pullable crystal. 2 MDS 3711 F Int egrat ed C ircuit Syste ms Pin Description ● 525 R ace S tr eet, San Jose, CA 95126 Revision 070301 ● t el (40 8) 295 -9800 ● w ww. ic s t .c o m MK3711 LOW COST 8 - 16 MHZ 3.3 VOLT VCXO External Component Selection The MK3711 requires a minimum number of external components for proper operation. Decoupling Capacitor A decoupling capacitor of 0.01µF must be connected between VDD (pin 2) and GND (pin 4), as close to these pins 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. Series Termination Resistor When the PCB trace between the clock output (CLK, pin 5) 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 MK3711 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. The frequency of oscillation of a quartz crystal is determined by its “cut” and by the load capacitors connected to it. The MK3711 incorporates on-chip variable load capacitors that “pull” (change) the frequency of the crystal. The crystal specified for use with the MK3711 is designed to have zero frequency error when the total of on-chip + stray capacitance is 14pF. Recommended Crystal Parameters: Initial Accuracy at 25°C Temperature Stability Aging Load Capacitance Shunt Capacitance, C0 C0/C1 Ratio Equivalent Series Resistance ±20 ppm ±30 ppm ±20 ppm 14 pf 7 pF Max 250 Max 35 Ω Max For crystal frequencies between 13.5MHz and 16MHz, the nominal crystal load capacitance specification should be 14pF. Contact ICS MicroClock applications regarding the use of a crystal below 13.5MHz. 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 MK3711. 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. 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. To determine the need for and value of the crystal adjustment capacitors, you will need a PC board of your final layout, a frequency counter capable of about 1 ppm resolution and accuracy, two power supplies, and some samples of the crystals which you plan to use in production, along with measured initial accuracy for each crystal at the specified crystal load capacitance, CL. To determine the value of the crystal capacitors: 1. Connect VDD of the MK3711 to 3.3V. Connect pin 3 of the MK3711 to the second power supply. Adjust the voltage on pin 3 to 0V. Measure and record the frequency of the CLK output. 2. Adjust the voltage on pin 3 to 3.3V. Measure and record the frequency of the same output. To calculate the centering error: 6 ( f 3.0V – f t arg et ) + ( f 0V – f t arg et ) Error = 10 x ------------------------------------------------------------------------------ – errorxtal ft arg et Where: 3 MDS 3711 F Int egrat ed C ircuit Syste ms ● 525 R ace S tr eet, San Jose, CA 95126 Revision 070301 ● t el (40 8) 295 -9800 ● w ww. ic s t .c o m MK3711 LOW COST 8 - 16 MHZ 3.3 VOLT VCXO ftarget = nominal crystal frequency errorxtal =actual initial accuracy (in ppm) of the crystal being measured If the centering error is less than ±25 ppm, no adjustment is needed. If the centering error is more than 25ppm negative, the PC board has excessive stray capacitance and a new PCB layout should be considered to reduce stray capacitance. (Alternately, the crystal may be re-specified to a higher load capacitance. Contact ICS MicroClock for details.) If the centering error is more than 25ppm positive, add identical fixed centering capacitors from each crystal pin to ground. The value for each of these caps (in pF) is given by: External Capacitor = 2 x (centering error)/(trim sensitivity) Trim sensitivity is a parameter which can be supplied by your crystal vendor. If you do not know the value, assume it is 30 ppm/pF. After any changes, repeat the measurement to verify that the remaining error is acceptably low (typically less than ±25ppm). Absolute Maximum Ratings Stresses above the ratings listed below can cause permanent damage to the MK3711. 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 -0.5V to VDD+0.5V 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 4 MDS 3711 F Int egrat ed C ircuit Syste ms Refer to page 3 ● 525 R ace S tr eet, San Jose, CA 95126 Revision 070301 ● t el (40 8) 295 -9800 ● w ww. ic s t .c o m MK3711 LOW COST 8 - 16 MHZ 3.3 VOLT VCXO DC Electrical Characteristics VDD=3.3V ±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 Output = 12 MHz, no load Short Circuit Current IOS VIN, VCXO Control Voltage VIA Min. Typ. 3.15 Max. Units 3.45 V 2.4 V 0.4 V VDD-0.4 V 7 mA ±50 mA 0 3.3 V AC Electrical Characteristics VDD = 3.3V ±5%, Ambient Temperature 0 to +70° C, unless stated otherwise Parameter Symbol Conditions Min. Typ. Max. Units Output Frequency 8 16 MHz MK3711D and MK3711B FO MK3711A and MK3711S FO VCXO Crystal frequency = 12 MHz MK3711D and MK3711B FP 0V< VIN < 3.3V, Note 1 + 115 ppm MK3711A and MK3711S FP 0V< VIN < 3.3V, Note 1 + 100 ppm 12 MHz Crystal Pullability VCXO Gain MK3711D VIN = VDD/2 + 1V, Note 1 120 ppm/V MK3711B VIN = VDD/2 + 1V, Note 1 150 ppm/V MK3711A VIN = VDD/2 + 1V, Note 1 170 ppm/V MK3711S VIN = VDD/2 + 1V, Note 1 100 ppm/V Output Rise Time tOR 0.8 to 2.0V, CL=15pF 1.5 ns Output Fall Time tOF 2.0 to 0.8V, CL=15pF 1.5 ns Output Clock Duty Cycle tD Measured at 1.4V, CL=15pF 60 % Maximum Output Jitter, short term tJ CL=15pF 40 50 100 ps Note 1: External crystal device must conform with Pullable Crystal Specifications listed on page 3. 5 MDS 3711 F Int egrat ed C ircuit Syste ms ● 525 R ace S tr eet, San Jose, CA 95126 Revision 070301 ● t el (40 8) 295 -9800 ● w ww. ic s t .c o m MK3711 LOW COST 8 - 16 MHZ 3.3 VOLT VCXO Package Outline and Package Dimensions (8 pin SOIC, 150 Mil. Narrow Body) Package dimensions are kept current with JEDEC Publication No. 95 Index Area E H Pin 1 h x 450 D Symbol Millimeters Min Max Inches Min Max A A1 B C D E e H h L a 1.35 1.75 1.10 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 (Note 1) Marking Shipping packaging Package Temperature MK3711D MK3711DTR MK3711B MK3711BTR MK3711A MK3711ATR MK3711S MK3711STR MK3711D MK3711D MK3711B MK3711B MK3711A MK3711A MK3711S MK3711S Tubes Tape and Reel Tubes Tape and Reel Tubes Tape and Reel Tubes Tape and Reel 8 pin SOIC 8 pin SOIC 8 pin SOIC 8 pin SOIC 8 pin SOIC 8 pin SOIC 8 pin SOIC 8 pin SOIC 0 to +70° C 0 to +70° C 0 to +70° C 0 to +70° C 0 to +70° C 0 to +70° C 0 to +70° C 0 to +70° C Note 1: MK3711D is recommended for new designs. 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 3711 F Int egrat ed C ircuit Syste ms ● 525 R ace S tr eet, San Jose, CA 95126 Revision 070301 ● t el (40 8) 295 -9800 ● w ww. ic s t .c o m