4 POWER SUPPLY
4-2
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
Operating Voltage (LV
4.2
DD
)
The CPU core and internal logic circuits operate with a voltage supplied between the LV
DD
and V
SS
pins.
The following operating voltage can be used:
LV
DD
= 1.65 to 1.95 V (V
SS
= GND)
or 1.7 to 1.9 V when a ceramic resonator is used
Note: The S1C33L26 packages have more than one LV
DD
and V
SS
pins. Be sure to supply the operating
voltage to all the pins. Do not open any of them.
Power Supply for PLL (PLLV
4.3
DD
, PLLV
SS
)
The PLL power supply pins (PLLV
DD
and PLLV
SS
) are provided separately from the LV
DD
and V
SS
pins so that the
digital circuits will not affect the PLL circuit. Supply the same voltage level as the LV
DD
to the PLLV
DD
.
PLLV
DD
= LV
DD
, PLLV
SS
= V
SS
Noise on the PLL power lines decrease the PLL output precision, so use a stabilized power supply and make the
board pattern with consideration given to that.
Power Supply for RTC (RTCV
4.4
DD
)
The RTC power supply pin (RTCV
DD
) is provided separately from the LV
DD
pin in order to run the RTC and OSC1
oscillator at system power down. Supply the same voltage level as the LV
DD
to the RTCV
DD
pin.
RTCV
DD
= LV
DD
(V
SS
= GND)
The RTCV
DD
is also used for the battery-backup RAM (BBRAM).
I/O Interface Voltage (HV
4.5
DD
)
The HV
DD
voltage is used for interfacing with external I/O signals. For the output interface of the S1C33L26, the
HV
DD
voltage is used as high level and the V
SS
voltage as low level. The V
SS
pin is used for the ground common
with LV
DD
. The effective HV
DD
voltage range is as follows:
HV
DD
= 2.7 to 3.6 V (V
SS
= GND)
or 3.0 to 3.6 V when the USB module is used
Note: The S1C33L26 packages have more than one HV
DD
pins. Be sure to supply the operating voltage
to all the pins. Do not open any of them.
Power Supply for Analog Circuits (AV
4.6
DD
)
The analog power supply pin (AV
DD
) is provided separately from other power supply pins so that the digital circuits
will not affect the analog circuits (A/D converter). The AV
DD
pin is used to supply an analog power voltage and the
V
SS
pin is used as the analog ground. The effective AV
DD
voltage range is as follows:
AV
DD
= 2.7 to 3.6 V (V
SS
= GND)
Note: Be sure to supply a voltage within the range from 2.7 to 3.6 V to the AV
DD
pin even if the analog
circuit is not used.
Noise on the analog power lines decrease the A/D converting precision, so use a stabilized power supply and make
the board pattern with consideration given to that.