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19-3492; Rev 0; 1/05
Silicon Oscillator with Low-Power Frequency Switching
General Description
The MAX7383 dual-speed silicon oscillator replaces ceramic resonators, crystals, and crystal-oscillator modules as the primary and secondary clock source for microcontrollers in 3V, 3.3V, and 5V applications. The MAX7383 features a factory-programmed high-speed oscillator, a 32.768kHz oscillator, and a clock-selector input. The clock output can be switched at any time between the high-speed clock and the 32.768kHz clock for low-power operation. Switchover is synchronized internally to provide glitch-free clock switching. Unlike typical crystal and ceramic-resonator oscillator circuits, the MAX7383 is resistant to vibration and EMI. The high-output-drive current and absence of highimpedance nodes makes the oscillator less susceptible to dirty or humid operating conditions. With a wide operating temperature range as standard, the MAX7383 is a good choice for demanding home appliance and automotive environments. The MAX7383 is available with factory-programmed frequencies ranging from 10MHz to 32MHz. See Table 1 for standard frequencies and contact the factory for custom frequencies. Refer to the MAX7377 data sheet for frequencies less than 10MHz. The MAX7383 is available in a 5-pin SOT23 package. The MAX7383 standard operating temperature range is -40C to +125C. See the Applications Information section for extended operating temperature range. 2.7V to 5.5V Operation High-Speed Oscillator from 10MHz to 32MHz Low-Speed 32kHz Oscillator Glitch-Free Clock-Speed Switching 10mA Clock-Output Drive Capability 2.5% Initial Accuracy 50ppm/C (typ) Frequency Drift 50% Duty Cycle 5ns Output Rise and Fall Time Low Jitter: 80psP-P at 16MHz 4mA Operating Current at 16MHz 13A, 32kHz Operating Current -40C to +125C Temperature Range Small 5-Pin SOT23 Package
Features
MAX7383
Ordering Information
PART* TEMP RANGE PINPACKAGE RESET OUTPUT Active high push-pull
MAX7383AX _ _-T -40C to +125C 5 SOT23-5
Applications
White Goods Automotive Consumer Products Appliances and Controls Handheld Products Portable Equipment Microcontroller Systems
*The first two letters are AX. Insert the two-letter code from Table 2 in the remaining two positions for the desired frequency range. Insert the two-letter code from Table 1 in the remaining two positions for the desired frequency range. Table 1 is located at the end of the data sheet.
Typical Operating Circuit
VCC 2.7V TO 5.5V
0.1F
VCC CLOCK
OSC1
OSC2
MAX7383
E.C. I/O PORT SPEED GND C
Pin Configuration appears at end of data sheet. ________________________________________________________________ Maxim Integrated Products 1
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.
Silicon Oscillator with Low-Power Frequency Switching MAX7383
ABSOLUTE MAXIMUM RATINGS
VCC to GND ...........................................................-0.3V to +6.0V All Other Pins to GND...................................-0.3V to (V+ + 0.3V) CLOCK Current ...............................................................50mA Input Current (SPEED)......................................................50mA Continuous Power Dissipation (TA = +70C) 5-Pin SOT23 (derate 7.1mW/C above +70C)....571mW (U5-2) Operating Temperature Range .........................-55C to +135C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
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
(Typical Operating Circuit, VCC = 2.7V to 5.5V, VL = VCC, TA = -40C to +125C. Typical values are at VCC = 5.0V, TA = +25C, unless otherwise noted.) (Note 1)
PARAMETER Operating Supply Voltage SYMBOL VCC fCLOCK = 16MHz, TA = -40C to +125C, no load fCLOCK = 14.7456MHz, TA = -40C to +125C, no load fCLOCK = 12MHz, TA = -40C to +125C, no load Operating Supply Current ICC fCLOCK = 11.0592MHz, TA = -40C to +125C, no load fCLOCK = 10MHz, TA = -40C to +125C, no load fCLOCK = 32.768kHz, TA = -40C to +125C, no load LOGIC INPUTS (SPEED) Input High Voltage Input Low Voltage Input Current CLOCK OUTPUT Output High Voltage Output Low Voltage VOH VOL VL = 4.5V, ISOURCE = 7.0mA VL = 2.7V, ISOURCE = 2.0mA VL = 4.5V, ISINK = 20mA VL = 2.7V, ISINK = 10mA VCC = 5V, TA = +25C, deviation from selected frequency Fast Clock Frequency Accuracy fCLOCK VCC = 2.7V to 5.5V, TA = +25C, deviation from selected frequency TA = -40C to +125C -2.5 -5.0 50 VL - 0.4 0.4 +2.5 % +3.5 350 ppm/C V V VIH VIL IIN VCC SPEED = 5.5V 0.7 x VCC 0.3 x VCC 2 V V A 13 CONDITIONS MIN 2.7 TYP MAX 5.5 8.7 8.0 6.5 6.0 5.4 25 A mA UNITS V
Fast Clock Temperature Coefficient
2
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Silicon Oscillator with Low-Power Frequency Switching
ELECTRICAL CHARACTERISTICS (continued)
(Typical Operating Circuit, VCC = 2.7V to 5.5V, VL = VCC, TA = -40C to +125C. Typical values are at VCC = 5.0V, TA = +25C, unless otherwise noted.) (Note 1)
PARAMETER Slow Clock Frequency Slow Clock Temperature Coefficient Duty Cycle Output Jitter Output Rise Time Output Fall Time Undervoltage Lockout Threshold Undervoltage Lockout Hysteresis tR tF VTH SYMBOL fCLOCK CONDITIONS VCC = 5V, TA = +25C VCC = 2.7V to 5.5V, TA = +25C TA = -40C to +125C (Note 2) Observation of 16MHz for 20s using a 500MHz oscilloscope 10% to 90% 90% to 10% VCC rising, deviation from nominal threshold TA = +25C TA = -40C to +125C 2.45 2.37 1 40 MIN 32.268 31.768 TYP 32.768 32.768 50 50 80 5 5 2.55 2.63 % MAX 33.268 33.768 325 60 UNITS kHz ppm/C % psP-P ns ns
MAX7383
HYST
Difference between rising and falling thresholds
%
Note 1: All parameters tested at TA = +25C. Specifications over temperature are guaranteed by design. Note 2: Guaranteed by design. Not production tested.
Typical Operating Characteristics
(VCC = VL = 5V, TA = +25C, frequency = 10MHz, unless otherwise noted.)
DUTY CYCLE vs. TEMPERATURE
MAX7383 toc01
DUTY CYCLE vs. SUPPLY VOLTAGE
FREQUENCY = 11.0592MHz 50 DUTY CYCLE (%) 49 48 47 46 45
MAX7383 toc02
SUPPLY CURRENT vs. TEMPERATURE
MAX7383 toc03
50.5
51
3.25 3.20 SUPPLY CURRENT (mA) 3.15 3.10 FREQUENCY = 10MHz 3.05 3.00 2.95 2.90
50.0 DUTY CYCLE (%)
49.5
FREQUENCY = 10MHz
49.0
48.5
48.0 -55 -17 21 59 97 135 TEMPERATURE (C)
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
-55
-17
21
59
97
135
SUPPLY VOLTAGE (V)
TEMPERATURE (C)
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3
Silicon Oscillator with Low-Power Frequency Switching MAX7383
Typical Operating Characteristics (continued)
(VCC = VL = 5V, TA = +25C, frequency = 10MHz, unless otherwise noted.)
FREQUENCY DEVIATION vs. SUPPLY VOLTAGE
FREQUENCY = 11.0592MHz 1.5 FREQUENCY DEVIATION (%) 1.0 0.5 0 -0.5 -1.0 -1.5 1.5 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 SUPPLY VOLTAGE (V) -2.0 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 SUPPLY VOLTAGE (V)
MAX7383 toc05
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX7383 toc04
FREQUENCY DEVIATION vs. TEMPERATURE
FREQUENCY = 10MHz 3 FREQUENCY DEVIATION (%) 2 1 0 -1 -2 -3 -4 -55 -17 21 59 97 135 TEMPERATURE (C)
MAX7383 toc06 MAX7383 toc09 MAX7383 toc12 MAX7383 toc11
4.0 FREQUENCY = 11.0592MHz 3.5 SUPPLY CURRENT (mA)
2.0
4
3.0
2.5
2.0
SETTLING TIME FROM START
MAX7383 toc07
CLOCK OUTPUT WAVEFORM (CL = 10pF)
MAX7383 toc08
CLOCK OUTPUT WAVEFORM (CL = 10pF)
CH1 FREQ 9.992MHz LOW RESOLUTION
10s/div CHANNEL 1 = CLOCK, CHANNEL 2 = VCC
20ns/div
20ns/div
CLOCK OUTPUT WAVEFORM (CL = 100pF)
SUPPLY CURRENT vs. FREQUENCY
5
HIGH-SPEED TO LOW-SPEED TRANSITION
MAX7383 toc10
SUPPLY CURRENT (mA)
4
3
2
1 20ns/div 10 11 12 13 14 15 16 10s/div CHANNEL 1 = CLOCK, CHANNEL 2 = SPEED FREQUENCY (MHz)
4
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Silicon Oscillator with Low-Power Frequency Switching
Typical Operating Characteristics (continued)
(VCC = VL = 5V, TA = +25C, frequency = 10MHz, unless otherwise noted.)
HIGH-SPEED TO LOW-SPEED TRANSITION (DETAIL ZOOM)
MAX7383 toc13
MAX7383
LOW-SPEED TO HIGH-SPEED TRANSITION
MAX7383 toc14
LOW-SPEED TO HIGH-SPEED TRANSITION (DETAIL ZOOM)
MAX7383 toc15
40ns/div CHANNEL 1 = CLOCK, CHANNEL 2 = SPEED
10s/div CHANNEL 1 = CLOCK, CHANNEL 2 = SPEED
100ns/div CHANNEL 1 = CLOCK, CHANNEL 2 = SPEED
Pin Description
PIN 1 2 3 4 5 NAME CLOCK GND SPEED VCC E.C. Push-Pull Clock Output Ground Clock Speed Select Input. Drive SPEED low to select the 32kHz fixed frequency. Drive SPEED high to select the factory-trimmed frequency. Positive Supply Voltage. Bypass VCC to GND with a 0.1F capacitor. Externally Connected. Connect to Vcc. FUNCTION
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5
Silicon Oscillator with Low-Power Frequency Switching MAX7383
Detailed Description
The MAX7383 is a dual-speed clock generator for microcontrollers (Cs) and UARTs in 3V, 3.3V, and 5V applications. The MAX7383 is a replacement for two crystal-oscillator modules, crystals, or ceramic resonators. The high-speed clock frequency is factory trimmed to specific values. A variety of popular standard frequencies are available. The low-speed clock frequency is fixed at 32.768kHz. See Table 1. No external components are required for setting or adjusting the frequency.
Table 1. Standard Frequencies
SUFFIX UK UT VB VT WB YN STANDARD FREQUENCY (MHz) 10 11.0592 12 14.7456 16 32
For all other frequency options, contact factory.
Oscillator
The push-pull clock output drives a load to within 400mV of either supply rail. The clock output remains stable over the full operating voltage range and does not generate short output cycles during either power-on or changing of the frequency. A typical oscillating startup is shown in the Typical Operating Characteristics.
Table 2. Standard Part Numbers
PART MAX7383AXUK MAX7383AXUT MAX7383AXVB MAX7383AXVT MAX7383AXWB MAX7383AXYN* FREQUENCY (MHz) 10 11.0592 12 14.7456 16 32 TOP MARK AEVN AEVO AEVP AEVQ AEVT AEVS
Clock-Speed Selection
Drive SPEED low to select slow clock speed (nominally 32.768kHz) or high to select full clock speed. SPEED can be connected to VCC or to GND to select fast or slow clock speed, or connected to a logic output (such as a P GPIO port) used to change clock speed on the fly. If SPEED is connected to a P GPIO port, connect a pullup or pulldown resistor to set the clock to the preferred speed on power-up. SPEED input bias current is 2A max, so a resistor value as high as 500k can be used.
*Contact factory for availability.
Applications Information
Interfacing to a Microcontroller Clock Input
The MAX7383 clock output is a push-pull, CMOS, logic output that directly drives a P or C clock input. There are no impedance-matching issues when using the MAX7383. Refer to the microcontroller data sheet for clock input compatibility with external clock signals. The MAX7383 requires no biasing components or load capacitance. When using the MAX7383 to retrofit a crystal oscillator, remove all biasing components from the oscillator input.
VCC
MAX7383
32kHz (LF OSCILLATOR) SPEED
UVLO
Output Jitter
LOGIC 10MHz TO 32MHz (HF OSCILLATOR) MUX CLOCK
GND
Figure 1. Functional Diagram
The MAX7383's jitter performance is given in the Electrical Characteristics table as a peak-to-peak value obtained by observing the output of the MAX7383 for 20s with a 12GHz oscilloscope. Jitter measurements are approximately proportional to the period of the output of the device. Thus, a 10MHz device has approximately twice the jitter value of a 20MHz device. The jitter performance of all clock sources degrades in the presence of mechanical and electrical interference. The MAX7383 is relatively immune to vibration, shock, and EMI influences and thus provides a considerably
6
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Silicon Oscillator with Low-Power Frequency Switching
more robust clock source than crystal or ceramic resonator-based oscillator circuits.
Pin Configuration
TOP VIEW
CLOCK 1 5 E.C.
MAX7383
Initial Power-Up and Operation
An internal-undervoltage lockout function holds the clock output low until the supply voltage has risen above 2.5V. The clock output then starts at the frequency selected by SPEED.
Extended Temperature Operation
The MAX7383 was tested to +135C during product characterization and shown to function normally at this temperature (see the Typical Operating Characteristics). However, production test and qualification is only performed from -40C to +125C at this time. Contact the factory if operation outside this range is required.
GND 2
MAX7383
SPEED 3
4
VCC
SOT23
Power-Supply Considerations
The MAX7383 operates with power-supply voltages from 2.7V and 5.5V. Good power-supply decoupling is needed to maintain the power-supply rejection performance of the MAX7383. Bypass VCC to GND with a 0.1F surface-mount ceramic capacitor. Mount the bypassing capacitor as close to the device as possible. Use a larger value of bypass capacitor recommended if the MAX7383 is to operate with a large capacitive load. Use a bypass capacitor value of at least 1000 times that of the output load capacitance.
Chip Information
TRANSISTOR COUNT: 2937 PROCESS: BiCMOS
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Silicon Oscillator with Low-Power Frequency Switching
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.)
MAX7383
PACKAGE OUTLINE, SOT-23, 5L
21-0057
E
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.
8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.
SOT-23 5L .EPS

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