CC2420 Datasheet, PDF (51/87 Pages) List of Unclassifed Manufacturers – 2.4 GHz IEEE 802.15.4 / ZigBee-ready RF Transceiver

SmartRF ^® CC2420
1.6 V. CC2420 should then be reset before
the voltage regulator is disabled.
In applications where the internal voltage
regulator is not used, connect VREG_EN
and VREG_IN to ground. VREG_OUT shall
be left open. Note that the battery monitor
will not work when the voltage regulator is
not used.
VREG_EN
VREG_IN
Regulator
Enable / disable
Internal
bandgap
voltage
reference
1.25 V
VREG_OUT
Figure 27. Voltage regulator, simplified schematic
Battery Monitor
The on-chip battery monitor enables
monitoring the unregulated voltage on the
VREG_IN pin. It gives status information
on the voltage being above or below a
programmable threshold. A simplified
schematic of the battery monitor is shown
in Figure 28.
Chipcon AS SmartRF^® CC2420 Preliminary Datasheet (rev 1.2), 2004-06-09
Page 51 of 87