19-3697; Rev 0; 4/05 3-Pin Silicon Oscillator The MAX7381 is a silicon oscillator intended as a low-cost improvement to ceramic resonators, crystals, and crystal oscillator modules as the clock source for microcontrollers and UARTs in 3V, 3.3V, and 5V applications. The MAX7381 is an integrated oscillator, supplied at specific frequencies, just like crystals and resonators, and with a rail-to-rail, 50%, duty-cycle square-wave output. The oscillator frequency is generated directly without the use of a phase-locked loop (PLL). No additional components are required for setting or adjusting the frequency. Unlike typical crystal and ceramic resonator oscillator circuits, the MAX7381 is resistant to vibration and EMI. The high output-drive current and absence of high-impedance nodes make the oscillator invulnerable to dirty or humid operating conditions. With a wide operating temperature range as standard, the oscillator is a good choice for demanding appliance and automotive environments. The MAX7381 is available with frequencies in the 10MHz to 16MHz range. The MAX7381 is offered in a space-saving 3-pin SC70 package. All ICs are guaranteed to operate over the -55°C to +135°C temperature range and specified from the -40°C to +125°C temperature range. Features ♦ 2.7V to 5.5V Operation ♦ Factory-Trimmed Oscillator (10MHz to 16MHz) ♦ No External Components Required ♦ ±10mA Output-Drive Current ♦ 2% Initial Accuracy ♦ ±100ppm/°C Temperature Drift ♦ Fast Startup Time: 5µs ♦ 40% to 60% Maximum Duty Cycle ♦ 5ns Output Rise/Fall Time ♦ Very-Low-EMI Susceptibility (No High-Impedance Nodes) ♦ No PLL ♦ Low Jitter: 180psP-P at 16MHz ♦ -40°C to +125°C Temperature Range Ordering Information Applications PART TEMP RANGE PIN-PACKAGE White Goods Automotive MAX7381AXR106-T -40°C to +125°C 3 SC70-3 Appliances and Controls Handheld Products MAX7381AXR126-T -40°C to +125°C 3 SC70-3 MAX7381AXR146-T -40°C to +125°C 3 SC70-3 MAX7381AXR166-T -40°C to +125°C 3 SC70-3 Portable Equipment Microcontroller Systems Typical Operating Circuit 2.7V TO 5.5V The MAX7381 is available in factory-set frequencies from 10MHz to 16MHz. There are four standard versions 10MHz, 12MHz, 14MHz, and 16MHz, shown in the Selector Guide) with a required order increment of 2.5K. Nonstandard frequencies are also available with a required order increment of 10K. For nonstandard versions, contact factory for availability and ordering information. All versions are available in tape and reel only. Refer to the MAX7375 data sheet for output frequencies below 10MHz. V+ OSC1 CLOCK MAX7381 µC GND OSC2 Selector Guide appears at end of data sheet. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX7381 General Description MAX7381 3-Pin Silicon Oscillator ABSOLUTE MAXIMUM RATINGS V+ to GND .............................................................-0.3V to +6.0V CLK to GND..................................................-0.3V to (V+ + 0.3V) CLK Current .....................................................................±50mA Continuous Power Dissipation (TA = + 70°C) 3-Pin SC70 (derate 2.9mW/°C over +70°C) ..............235.3mW Functional Temperature Range .........................-55°C to +135°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (V+ = 2.7V to 5.5V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at V+ = 5V, TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL Operating Supply Voltage V+ Operating Supply Current I+ Output High Voltage Output Low Voltage VOL fCLOCK MIN TYP 2.7 MAX UNITS 5.5 V MAX7381AXR126 3.7 4.75 MAX7381AXR166 4.8 6.50 V+ ≥ 2.7V, ISOURCE = 2.5mA V+ 0.4 V+ ≥ 4.5V, ISOURCE = 9mA V+ 0.4 VOH On-Resistance Initial CLOCK Frequency (Note 2) CONDITIONS mA V V+ ≥ 2.7V, ISINK = 10mA 0.4 V+ ≥ 4.5V, ISINK = 20mA 0.4 VIN = 3V (typ value at TA = +25°C) 0.11 0.17 VIN = 5V (typ value at TA = +25°C) 0.095 0.15 V+ = 5.0V, TA = +25°C MAX7381AXR_ _ _ -2% +2% V+ = 2.7V to 5.5V, TA = +25°C MAX7381AXR_ _ _ -5% +3% V Ω MHz CLOCK Frequency Temperature Sensitivity TA = -40°C to +125°C, (Note 3) Duty Cycle (Note 3) Output Jitter Observation for 20s using a 12GHz oscilloscope (MAX7381AXR166) -350 100 +300 ppm/°C 40 50 60 % 180 psP-P Output Rise Time tR 5 ns Output Fall Time tF 5 ns 5 µs Startup Time Note 1: All parameters tested at TA = +25°C. Specifications over temperature are guaranteed by design and characterization. Note 2: Typical frequencies are nominal values. Note 3: Guaranteed by design and characterization. Not production tested. 2 _______________________________________________________________________________________ 3-Pin Silicon Oscillator DUTY CYCLE (%) 52 53 51 50 49 51 49 48 47 V+ = 5V 5 SUPPLY CURRENT (mA) 53 SUPPLY CURRENT vs. TEMPERATURE 6 MAX7381 toc02 MAX7381 toc01 54 DUTY CYCLE (%) DUTY CYCLE vs. SUPPLY VOLTAGE 55 MAX7381 toc03 DUTY CYCLE vs. TEMPERATURE 55 V+ = 3.3V 4 MAX7381 Typical Operating Characteristics (V+ = 5V, CL = 10pF, 16MHz output, TA = +25°C, unless otherwise noted.) 3 V+ = 2.7V 2 47 1 46 45 0 2.5 -40 -25 -10 5 20 35 50 65 80 95 110 125 3.0 TEMPERATURE (°C) SUPPLY CURRENT vs. SUPPLY VOLTAGE 4.5 5.0 5.5 -40 -25 -10 5 20 35 50 65 80 95 110 125 FREQUENCY vs. SUPPLY VOLTAGE 2 1 MAX7381 toc05 1.035 1.025 NORMALIZED FREQUENCY 3 FREQUENCY vs. TEMPERATURE 1.005 NORMALIZED FREQUENCY 4 TEMPERATURE (°C) 1.010 MAX7381 toc04 5 SUPPLY CURRENT (mA) 4.0 SUPPLY VOLTAGE (V) 6 1.000 0.995 0.990 0.985 0 3.0 3.5 4.0 4.5 5.0 5.5 1.015 1.005 0.995 0.985 0.975 0.980 2.5 2.5 3.0 3.5 4.0 4.5 5.0 5.5 -40 -25 -10 5 20 35 50 65 80 95 110 125 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) TEMPERATURE (°C) SUPPLY CURRENT vs. FREQUENCY SETTLING TIME FROM START CLOCK OUTPUT WAVEFORM WITH CL = 10pF MAX7381 toc09 MAX7381 toc08 MAX7381 toc07 6 5 SUPPLY CURRENT (mA) 3.5 MAX7381 toc06 45 4 CLOCK 1V/div CLOCK 2V/div 3 V+ 2V/div 2 1 V+ = 3.3V V+ = 3.3V V+ = 5V 0 10 11 12 13 14 15 16 100ns/div 20ns/div FREQUENCY (MHz) _______________________________________________________________________________________ 3 MAX7381 3-Pin Silicon Oscillator Typical Operating Characteristics (continued) (V+ = 5V, CL = 10pF, 16MHz output, TA = +25°C, unless otherwise noted.) CLOCK OUTPUT WAVEFORM WITH CL = 50pF CLOCK OUTPUT WAVEFORM WITH CL = 100pF MAX7381 toc10 MAX7381 toc11 CLOCK 1V/div CLOCK 1V/div V+ = 3.3V V+ = 3.3V 20ns/div 20ns/div Detailed Description The MAX7381 is a replacement for ceramic resonators, crystals, and crystal-oscillator modules as the clock source for microcontrollers and UARTs in 3V, 3.3V, and 5V applications. The MAX7381 is an integrated oscillator, supplied at specific frequencies just like crystals and resonators. A variety of popular standard frequencies are available. No external components are required for setting or adjusting the frequency. Supply Voltages The MAX7381 has been designed for use in systems with nominal supply voltages of 3V, 3.3V, or 5V and is specified for operation with supply voltages in the 2.7V to 5.5V range. Operation outside this range is not guaranteed. See the Absolute Maximum Ratings for limit values of power-supply and pin voltages. Oscillator The clock output is a push-pull configuration and is capable of driving a ground-connected 1kΩ load or a positive-supply-connected 500Ω load to within 400mV of either supply rail. The clock output remains stable over the full operating voltage range. A typical startup characteristic is shown in the Typical Operating Characteristics section. Output Jitter The MAX7381’s jitter performance is given in the Electrical Characteristics table as a peak-to-peak value obtained by observing the output of the MAX7381 for 20s with a 500MHz oscilloscope. Jitter measurements 4 Pin Description PIN NAME FUNCTION 1 V+ Positive Supply Voltage. Bypass V+ to GND with a 0.1µF surface-mount ceramic capacitor. 2 CLOCK 3 GND Clock Output. CLOCK is a pushpull output. Ground are approximately proportional to the period of the output frequency of the device. The jitter performance of all clock sources degrades in the presence of mechanical and electrical interference. The MAX7381 is relatively immune to vibration, shock, and EMI influences, and thus provides a considerably more robust clock source than crystal- or ceramicresonator-based oscillator circuits. Applications Information Interfacing to a Microcontroller Clock Input The MAX7381 clock output is a push-pull, CMOS, logic output, which directly drives any microprocessor (µP) or microcontroller (µC) clock input. There are no impedance-matching issues when using the MAX7381. Operate the MAX7381 and microcontroller (or other clock-input device) from the same supply voltage. Refer to the microcontroller data sheet for clock-input compatibility with external clock signals. _______________________________________________________________________________________ 3-Pin Silicon Oscillator Chip Information PROCESS: BiCMOS Startup Performance The MAX7381 oscillator output stabilizes within a few cycles of operation after V+ rises to a sufficient voltage to start the oscillator, typically 1.65V at +25°C. Use a reset or similar voltage-detection circuit to disable devices connected to the MAX7381 until 20µs after the voltage on V+ has risen above 2.7V. Power-Supply Considerations The MAX7381 operates with power-supply voltages in the 2.7V to 5.5V range. Power-supply decoupling is needed to maintain the power-supply rejection performance of the MAX7381. Use a 0.1µF surface-mount ceramic capacitor connected between V+ and GND and mounted as close to the device as possible. If possible, mount the MAX7381 close to the microcontroller’s decoupling capacitor so that additional decoupling is not required. A larger value bypass capacitor is recommended if the MAX7381 is driving a large capacitive load. Use a bypass capacitor value of at least 1000 times the output-load capacitance. Selector Guide PART FREQUENCY (MHz) TOP MARK MAX7381AXR106 10 APE MAX7381AXR126 12 APG MAX7381AXR146 14 ARC MAX7381AXR166 16 APH Pin Configuration TOP VIEW V+ 1 MAX7381 3 GND CLOCK 2 SC70 _______________________________________________________________________________________ 5 MAX7381 The MAX7381 requires no biasing components or load capacitance. When using the MAX7381 to retrofit a crystal oscillator, remove all biasing components from the oscillator input. Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) SC70, 3L.EPS MAX7381 3-Pin Silicon Oscillator PACKAGE OUTLINE, 3L SC70 21-0075 C 1 1 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 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