CC2420 Chipcon AS, CC2420 Datasheet - Page 49

• Manufacturer Part Number: CC2420
• Description: 2.4 GHz RF Transceiver for IEEE 802.15.4 and ZigBee
• Manufacturer: Chipcon AS

Voltage Regulator
CC2420
regulator. This is used to provide a 1.8 V
power supply to the
supplies. The voltage regulator should not
be used to provide power to other circuits
because
capability and noise considerations.
The voltage regulator input pin VREG_IN
is connected to the unregulated 2.1 to 3.6
V power supply. The voltage regulator is
enabled / disabled using the active high
voltage regulator enable pin VREG_EN.
The regulated 1.8 V voltage output is
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
Chipcon AS SmartRF ® CC2420 Preliminary Datasheet (rev 1.0), 2003-11-17
includes a low drop-out voltage
of
limited
Figure 26. Voltage regulator, simplified schematic
power
reference
bandgap
Internal
voltage
CC2420
sourcing
Enable / disable
1.25 V
power
Regulator
VREG_EN
SmartRF
available
simplified
regulator is shown in Figure 26.
The voltage regulator requires external
components
Application Circuit section on page 17.
When disabling the voltage regulator, note
that register and RAM programming will
be lost as leakage current reduces the
output voltage on the VREG_OUT pin below
1.6 V.
the voltage regulator is disabled.
programmable
schematic of the battery monitor is shown
in Figure 27.
VREG_IN
CC2420
VREG_OUT
on
schematic
should then be reset before
as
the
threshold.
®
described
VREG_OUT
CC2420
of
A
the
Page 49 of 85
simplified
in
pin.
voltage
the
A