RF Quadrature Transceiver / RF Quadrature Receiver
CMX991/CMX992
5.5
VBIAS
The VBIAS pin provides a 1.6V bandgap reference-derived bias voltage (VBIAS) that may be used as a
reference voltage for differential amplifier stages (e.g. in the receiver output). The VBIAS pin can be
decoupled to ground but a capacitor greater than 200nF should be used to ensure stability.
5.6
Data Interface
The CMX991/CMX992 is controlled via a three wire C-BUS. A fourth pin (RDATA) is required if register
read-back is to be used. A further pin (RESETN) is provided which, when ‘low’, generates a reset signal
(see section for 6.1 further details). The pin should be pulled to the VDDIO supply with a suitable resistor if
not used.
The data interface can run at a lower voltage than the rest of the IC by setting the VDDIO supply to the
required interface voltage, in the range 1.6V to 3.6V.
Full details of the control register structure are given in section 6.
2012 CML Microsystems Plc
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CMLMICRO [ CML MICROCIRCUITS ]
