
SAM4CP [DATASHEET]
43051E–ATPL–08/14
16
5.1.5.2 Single Supply with Backup Battery
Figure 5-3
shows a typical single power supply scheme for VDDIO, VDDIN, VDDIN AN, VDDIN PLC, VDDCORE,
VDDPLL and VDDPLL PLC. VDDBU is supplied with a separate backup battery. In this supply scheme, the internal LCD
voltage regulator can be used. Note that if anti-tamper pins (TMP1 to TMP3) and the RTCOUT0 output have to be used
in backup mode, VDDIO must be kept. The reference voltage of the TMP1 to TMP3 and RTCOUT0 pins is VDDIO.
Note that PLC transceiver is not functional when working in backup mode.
Figure 5-3.
Single Supply with Backup Battery
Notes: 1.
Example with the SHDN pin used to control the main regulator enable pin. SHDN defaults to VDDBU at
startup and when the device wakes up from a wake-up event (external pin, RTC alarm, etc.). When the
device is in backup mode, SHDN defaults to 0.
- 10-bit ADC
- Temp. Sensor
- Voltage Ref.
Automatic
Power Switch
Backup Region
RTC, RTT
and
Backup Registers
VDDIN
Core Voltage
Regulator
VDDOUT
Main Supply
(3.0V-3.6V)
VDDCORE
VDDBU
VDDPLL
LCD Voltage
Regulator
VDDLCD
VDDIO
Main Supply
Voltage
Regulator
IN
OUT
PRIME PLC
Transceiver
LCD Buffers
+
LCD Switch Array
VDDIN AN
PLC Analog
Voltage
Regulator
PLC Digital
Voltage
Regulator
VDDOUT AN
ADC PLC
VDDIN PLC
VDDOUT PLC
VDDPLL PLC
Backup
Battery
+
-
Backup Power Supply
(1.6V-3.6V)
Shutdown (SHDN)
(1)
Force Wake-Up (FWUP)
External Wake-Up Signal
ON / OFF