The
ADF7901 is a
low power OOK/FSK UHF transmitter designed for use in RF remote control devices.
The device is capable of Frequency Shift Keying (FSK) modulation on eight different channels, selectable
by three external control lines. OOK modulation is performed by modulating the PA control line.
The on-chip VCO operates at 2x the output frequency. The divide by 2 at the output of the VCO reduces
the amount of PA feedthrough. As a result of this, OOK modulation depths of greater than 50dB are
easily achievable.
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The FSK_ADJ and ASK_ADJ resistors can be adjusted in the system to optimize output power for each
modulation scheme. An additional 1.5dB of output power is provided for the lower bank of channels
to adjust for antenna performance.
The CE line allows the transmitter to be powered down completely. In this mode the leakage current
is typically 0.1µA.
