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 imped-
ance-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 per-
formed 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 per-
formance 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 pos-
sible, 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
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