2
dc2048af
DEMO MANUAL DC2048A
performance summary
Specifications are at T
A
= 25°C
SYMBOL
PARAMETER
CONDITIONS
MIN
MAX
UNITS
V
IN
Input Voltage Range
3.0
18.0
V
V
BAT
Battery Voltage Range
1.8
5.5
V
V
OUT
1.8V
Output Voltage Range
OUT0 = 0, OUT1 = 0, OUT2 = 0
1.728
1.872
V
V
OUT
2.5V
Output Voltage Range
OUT0 = 1, OUT1 = 0, OUT2 = 0
2.425
2.575
V
V
OUT
2.8V
Output Voltage Range
OUT0 = 0, OUT1 = 1, OUT2 = 0
2.716
2.884
V
V
OUT
3.0V
Output Voltage Range
OUT0 = 1, OUT1 = 0, OUT2 = 0
2.910
3.090
V
V
OUT
3.3V
Output Voltage Range
OUT0 = 0, OUT1 = 0, OUT2 = 1
3.200
3.400
V
V
OUT
3.6V
Output Voltage Range
OUT0 = 1, OUT1 = 0, OUT2 = 1
3.492
3.708
V
V
OUT
4.5V
Output Voltage Range
OUT0 = 0, OUT1 = 1, OUT2 = 1
4.365
4.635
V
V
OUT
5.0V
Output Voltage Range
OUT0 = 1, OUT1 = 1, OUT2 = 1
4.850
5.150
V
LDO 1.2V
LDO Voltage Range
LDO0 = 0, LDO1 = 0, LDO2 = 0
1.176
1.224
V
LDO 1.5V
LDO Voltage Range
LDO0 = 1, LDO1 = 0, LDO2 = 0
1.470
1.530
V
LDO 1.8V
LDO Voltage Range
LDO0 = 0, LDO1 = 1, LDO2 = 0
1.764
1.836
V
LDO 2.0V
LDO Voltage Range
LDO0 = 1, LDO1 = 1, LDO2 = 0
1.960
2.040
V
LDO 2.5V
LDO Voltage Range
LDO0 = 0, LDO1 = 0, LDO2 = 1
2.450
2.550
V
LDO 3.0V
LDO Voltage Range
LDO0 = 1, LDO1 = 0 ,LDO2 = 1
2.940
3.060
V
LDO 3.3V
LDO Voltage Range
LDO0 = 0, LDO1 = 1, LDO2 = 1
3.234
3.366
V
LDO LD0_IN
LDO Voltage Range
LDO0 = 1, LDO1 = 1, LDO2 = 1
LDO_IN
V
Refer to the block diagram within the LTC3330 data sheet
for its operating principle.
The LTC3330 combines a buck switching regulator and
a buck-boost switching regulator to produce an energy
harvesting solution with battery backup. The converters are
controlled by a prioritizer that selects which converter to
use based on the availability of a battery and/or harvestable
energy. If harvested energy is available, the buck regula-
tor is active and the buck-boost is off. With an optional
LDO and supercapacitor balancer and an array of different
configurations, the LTC3330 suits many applications.
The synchronous buck converter is an ultralow quiescent
current power supply tailored to energy harvesting applica-
tions. It is designed to interface directly to a piezoelectric
or alternative A/C energy source, rectify and store the har-
vested energy on an external capacitor while maintaining a
regulated output voltage. It can also bleed off any excess
input power via an internal protective shunt regulator.
An internal full-wave bridge rectifier accessible via AC1
and AC2 inputs, rectifies AC sources such as those from
a piezoelectric element. The rectified output is stored on
a capacitor at the V
IN
pin and can be used as an energy
reservoir for the buck converter. The bridge rectifier has
a total drop of about 800mV at typical piezo-generated
currents, but is capable of carrying up to 50mA.
When the voltage on V
IN
rises above the UVLO rising
threshold the buck converter is enabled and charge is
transferred from the input capacitor to the output capaci-
tor. When the input capacitor voltage is depleted below
the UVLO falling threshold the buck converter is disabled.
These thresholds can be set according to Table 4 of the
data sheet which offers UVLO rising thresholds from 4V
to 18V with large or small hysteresis windows.
Two internal rails, CAP and V
IN2
, are generated from V
IN
and
are used to drive the high side PMOS and low side NMOS
of the buck converter, respectively. Additionally the V
IN2
operating principle
