EM2420 ETC [List of Unclassifed Manufacturers], EM2420 Datasheet - Page 53

• Manufacturer Part Number: EM2420
• Description: 2.4 GHz IEEE 802.15.4 / ZigBee RF Transceiver
• Manufacturer: ETC [List of Unclassifed Manufacturers]

Voltage Regulator
The EM2420 includes a low drop-out
voltage regulator. This is used to provide a
1.8 V power supply to the EM2420 power
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
Figure 26. 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
Ember Part Number: 120-0049-000C
of
limited
power
reference
bandgap
Internal
voltage
sourcing
Enable / disable
1.25 V
Regulator
VREG_EN
EM2420 Datasheet
available
simplified
regulator is shown in Figure 26.
The voltage regulator requires external
components
Application Circuit section on page 18.
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 EM2420 should then be reset
before the voltage regulator is disabled.
programmable
schematic of the battery monitor is shown
in Figure 27.
VREG_IN
VREG_OUT
on
schematic
as
the
threshold.
described
VREG_OUT
EM2420
of
A
the
Page 53 of 89
simplified
in
pin.
voltage
the
A