MAX7381
3-Pin Silicon Oscillator
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Typical Operating Characteristics (continued)
(V+ = 5V, CL= 10pF, 16MHz output, TA= +25°C, unless otherwise noted.)
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 oscilla-
tor, supplied at specific frequencies just like crystals
and resonators. A variety of popular standard frequen-
cies 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 guar-
anteed. 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 1kΩload or a
positive-supply-connected 500Ωload 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
are approximately proportional to the period of the out-
put 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 ceramic-
resonator-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 imped-
ance-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.
Pin Description