MAXIM MAX7375 User Manual

Page 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
General Description
The MAX7375 is a silicon oscillator, intended as a low­cost improvement replacing ceramic resonators, crys­tals, and crystal oscillator modules used as the clock source for microcontrollers and UARTs in 3V, 3.3V, and 5V applications.
The MAX7375 is a fully integrated oscillator, supplied at specific factory-trimmed frequencies 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 used to set or adjust the frequency.
Unlike typical crystal and ceramic resonator oscillator circuits, the MAX7375 is highly resistant to vibration and EMI. The high output drive current and absence of high-impedance nodes also makes the oscillator less susceptible to dirty or humid operating conditions. With a wide operating temperature range, the oscillator is a good choice for demanding home appliance and auto­motive environments.
Available in 3-pin space-saving SC70 package, the MAX7375 is offered in standard and nonstandard fac­tory-set frequencies ranging from 600kHz to 9.99MHz. See the MAX7381 data sheet for frequencies 10MHz. The MAX7375’s standard operating temperature range is -40°C to +125°C. See the Applications Information section for extended operating temperature range.
Applications
White Goods Portable Equipment
Automotive Microcontroller Systems
Appliances and Controls
Hand-Held Products
Features
2.7V to 5.5V OperationFactory-Trimmed Oscillator (600kHz to 9.99MHz)No External Components Required±10mA Output Drive Current2% Initial Accuracy±50ppm/°C Temp DriftFast Startup Time: 5µs40% to 60% Maximum Duty Cycle5ns Output Rise and Fall Time-Low EMIVery Low EMI Susceptibility-No High-Impedance
Nodes
Very Low Jitter: 160ps
P-P
at 8MHz
Tiny Surface-Mount Package (SC70)-40°C to +125°C Temperature Range
MAX7375
3-Pin Silicon Oscillator
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-3060; Rev 3; 12/07
Typical Application Circuit
Pin Configuration and Selector Guide appear at end of data sheet.
Note: The MAX7375 is available in factory-set frequencies from
600kHz to 9.99MHz. There are seven standard versions (1MHz,
1.84MHz, 3.58MHz, 3.69MHz, 4MHz, 4.19MHz, and 8MHz, as shown in the Selector Guide) with a required 2.5k order incre­ment. Nonstandard frequencies are also available with a required 10k order increment. For nonstandard versions, contact factory for availability and ordering information. All versions available in tape-and-reel only.
2.7V TO 5.5V
V+
CLOCK
OSC1
µC
PART TEMP RANGE PIN-PACKAGE
MAX7375AXR105-T -40°C to +125°C 3 SC70-3
MAX7375AXR185-T -40°C to +125°C 3 SC70-3
MAX7375AXR365-T -40°C to +125°C 3 SC70-3
MAX7375AXR375-T -40°C to +125°C 3 SC70-3
MAX7375AXR405-T -40°C to +125°C 3 SC70-3
MAX7375AXR425-T -40°C to +125°C 3 SC70-3
MAX7375AXR805-T -40°C to +125°C 3 SC70-3
MAX7375
GND
OSC2
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MAX7375
3-Pin Silicon Oscillator
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
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)
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.
Note 1: All parameters are 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.
V+ to GND ................................................................-0.3V to +6V
CLOCK to GND ............................................-0.3V to (V+ + 0.3V)
Continuous Power Dissipation (T
A
= +70°C)
3-Pin SC70 (derate 2.9mW/°C over +70°C).................235mW
Operating 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
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Operating Supply Voltage V+ 2.7 5.5 V
MAX7375A_R105 0.55 1.1
Operating Supply Current I+
Output High Voltage V
Output Low Voltage V
Initial CLOCK Frequency Accuracy
CLOCK Frequency Temperature Sensitivity
Duty Cycle (Note 3) 45 52 57 %
Output Jitter
Output Rise Time t
Output Fall Time t
OH
f
CLOCK
MAX7375A_R185 0.8 1.25
MAX7375A_R405 1.7 4.2
MAX7375A_R805 3.2 6.4
V+ 2.7V, I
V+ 4.5V, I
V+ 2.7, I
OL
V+ 4.5V, I
V+ = 3.0V, T
A
V+ = 2.7V to 5.5V, T
A
(Note 3) ±50 ±325 ppm/°C
Observation for 20s using a 500MHz oscilloscope (MAX7375A_R805)
(Note 3) 5.0 ns
R
(Note 3) 2.5 ns
F
SINK
= +25°C (Note 2)
= +25°C (Note 2)
= 2.5mA V+ - 0.4
SOURCE
= 9mA V+ - 0.4
SOURCE
= 10mA 0.4
= 20mA 0.4
SINK
MAX7375A_R_
MAX7375A_R_
_ _-2 +2
_ _-4 +4
160 ps
mA
V
V
%
P-P
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MAX7375
3-Pin Silicon Oscillator
_______________________________________________________________________________________ 3
Typical Operating Characteristics
(V+ = 5V, TA= +25°C, CL= 10pF, 8MHz output, unless otherwise noted.)
SUPPLY CURRENT vs. FREQUENCY
MAX7375 toc07
FREQUENCY (MHz)
SUPPLY CURRENT (mA)
6.54.52.5
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0
0.5 8.5
V+ = 5.5V
V+ = 5V
V+ = 3.3V
V+ = 2.7V
DUTY CYCLE vs. TEMPERATURE
55
54
53
52
51
50
49
DUTY CYCLE (%)
48
47
46
45
-40 125 TEMPERATURE (°C)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
4.0
3.5
3.0
2.5
2.0
SUPPLY CURRENT (mA)
1.5
1.0
2.7 5.5
SUPPLY VOLTAGE (V)
MAX7375 toc01
1109565 80-10 5 20 35 50-25
MAX7375 toc04
4.84.13.4
DUTY CYCLE vs. SUPPLY VOLTAGE
55
53
51
49
DUTY CYCLE (%)
47
45
2.7 5.5 SUPPLY VOLTAGE (V)
FREQUENCY vs. SUPPLY VOLTAGE
1.002
1.000
0.998
0.996
0.994
NORMALIZED FREQUENCY
0.992
0.990
2.7 5.5 SUPPLY VOLTAGE (V)
SUPPLY CURRENT vs. TEMPERATURE
4.0
3.5
MAX7375 toc02
3.0
2.5
2.0
1.5
SUPPLY CURRENT (mA)
1.0
0.5
4.84.13.4
0
-40 125
V+ = 2.7V
TEMPERATURE (°C)
FREQUENCY vs. TEMPERATURE
1.020
1.015
MAX7375 toc05
1.010
1.005
1.000
0.995
NORMALIZED FREQUENCY
0.990
0.985
4.84.13.4
0.980
-40 10-15 35 60 85 110 135 TEMPERATURE (°C)
V+ = 5V
MAX7375 toc03
V+ = 3.3V
1109565 80-10 5 20 35 50-25
MAX7375 toc06
CLOCK OUTPUT WAVEFORM
= 10pF
WITH C
L
V+ = 3.3V
40ns/div
MAX7375 toc09
SETTLING TIME FROM START
1µs/div
MAX7375 toc08
V+ = 3.3V
CLOCK 2V/div
V+ 2V/div
CLOCK 1V/div
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MAX7375
Detailed Description
The MAX7375 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 MAX7375 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 MAX7375 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 table 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 1kload or a
positive supply connected 500load to within 300mV 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 power off. A typical startup characteristic is shown in the Typical Operating Characteristics section.
Output Jitter
The MAX7375’s jitter performance is given in the Electrical Characteristics table as a peak-to-peak value obtained by observing the output of the MAX7375 for 20s with a 500MHz oscilloscope. Jitter measurements are approximately proportional to the period of the out­put frequency of the device. Thus, a 4MHz part has approximately twice the jitter value of an 8MHz part.
The jitter performance of all clock sources degrades in the presence of mechanical and electrical interference. The MAX7375 is relatively immune to vibration, shock, and EMI influences and thus provides a considerably more robust clock source than crystal- or ceramic-res­onator-based oscillator circuits.
3-Pin Silicon Oscillator
4 _______________________________________________________________________________________
Pin Description
Typical Operating Characteristics (continued)
(V+ = 5V, TA= +25°C, CL= 10pF, 8MHz output, unless otherwise noted.)
CLOCK OUTPUT WAVEFORM
WITH C
L
= 50pF
MAX7375 toc10
40ns/div
CLOCK 1V/div
V+ = 3.3V
CLOCK OUTPUT WAVEFORM
WITH C
L
= 100pF
MAX7375 toc11
40ns/div
CLOCK 1V/div
V+ = 3.3V
PIN
SC70
1 V+ Positive Supply Voltage
2 CLOCK Clock output. Output is push-pull.
3 GND Ground
NAME FUNCTION
Page 5
Applications Information
Interfacing to a Microcontroller Clock
Input
The MAX7375 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 MAX7375. Operate the MAX7375 and microcontroller (or other clock input device) from the same supply voltage level. Refer to the microcontroller data sheet for clock input compatibility with external clock signals.
The MAX7375 requires no biasing components or load capacitance. When using the MAX7375 to retrofit a crystal oscillator, remove all biasing components from the oscillator input.
Startup Performance
The MAX7375 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 MAX7375 until 5µs after the voltage on V+ has risen above 2.7V.
Extended Temperature Operation
The MAX7375 was tested to +135°C during product characterization and shown to function normally at this temperature (see Typical Operating Characteristics). However production test and qualification is only per­formed from -40°C to +125°C at this time. Contact the factory if operation outside this range is required.
Power-Supply Considerations
The MAX7375 operates with power-supply voltages in the 2.7V to 5.5V range. Good power-supply decoupling is needed to maintain the power-supply rejection per­formance of the MAX7375. 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 MAX7375 close to the microcontroller’s decoupling capacitor so that additional decoupling is not required.
A larger value of bypass capacitor is recommended if the MAX7375 is to operate with a large capacitive load. Use a bypass capacitor value of at least 1000 times that of the output load capacitance.
MAX7375
3-Pin Silicon Oscillator
_______________________________________________________________________________________ 5
Selector Guide
Pin Configuration
Chip Information
TRANSISTOR COUNT: 432
PROCESS: BiCMOS
PART FREQUENCY (MHz) TOP MARK
MAX7375AXR105 1.00 AOV
MAX7375AXR185 1.84 AOU
MAX7375AXR365 3.58 AOT
MAX7375AXR375 3.69 AOS
MAX7375AXR405 4.00 AOR
MAX7375AXR425 4.19 AOQ
MAX7375AXR805 8.00 AOP
TOP VIEW
1
V+
3 GND
CLOCK
MAX7375AXR
2
SC70
Page 6
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
.)
MAX7375
3-Pin Silicon Oscillator
6 _______________________________________________________________________________________
SC70, 3L.EPS
PACKAGE OUTLINE, 3L SC70
21-0075
1
C
1
Page 7
MAX7375
3-Pin Silicon Oscillator
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 7
© 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
Revision History
REVISION
NUMBER
0 10/03 Initial release
1—
2—
3 12/07 Removed all references to MAX7375AUR_ and SOT23 package. 1, 2, 4, 5
REVISION
DATE
DESCRIPTION
PAGES
CHANGED
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