LTC3108EDE-1#PBF Linear Technology, LTC3108EDE-1#PBF Datasheet - Page 10

• Manufacturer Part Number: LTC3108EDE-1#PBF
• Description: IC VOLTAGE CONVERTER 12-DFN
• Manufacturer: Linear Technology

Specifications of LTC3108EDE-1#PBF

• Applications: Energy Harvesting
• Current - Supply: 3mA
• Voltage - Supply: 20mV ~ 500mV
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 12-DFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

LTC3108-1
operaTion
In a typical application, a storage capacitor (typically a few
hundred microfarads) is connected to V
VAUX exceeds 2.5V, the V
charge up to its regulated voltage. The current available
to charge the capacitor will depend on the input voltage
and transformer turns ratio, but is limited to about 4.5mA
typical.
PGOOD
A power good comparator monitors the V
The PGD pin is an open-drain output with a weak pull-up
(1MΩ) to the LDO voltage. Once V
7.5% of its regulated voltage, the PGD output will go high.
If V
PGD will go low. The PGD output is designed to drive a
microprocessor or other chip I/O and is not intended to
drive a higher current load such as an LED. Pulling PGD
up externally to a voltage greater than VLDO will cause a
small current to be sourced into VLDO. PGD can be pulled
low in a wire-OR configuration with other circuitry.
V
V
host, using the V
connected to V
switch. This output, controlled by a host processor, can
be used to power external circuits such as sensors and
amplifiers, that do not have a low power sleep or shutdown
capability. V
when they are needed.
Minimizing the amount of decoupling capacitance on
V
shorter burst times and, therefore, smaller duty cycles in
pulsed applications such as a wireless sensor/transmit-
ter. A small V
that will be wasted in charging the capacitor every time
V
V
charging current and minimize glitching of the main output
when V
that limits the peak current to 0.3A typical.
0
OUT2
OUT2
OUT2
OUT2
OUT2
OUT
will allow it to be switched on and off faster, allowing
has a soft-start time of about 5µs to limit capacitor
is enabled.
is an output that can be turned on and off by the
OUT2
drops more than 9% from its regulated voltage,
OUT2
is enabled. It also has a current limiting circuit
OUT2
OUT
can be used to power these circuits only
capacitor will also minimize the energy
OUT2_EN
through a 1.3Ω P-channel MOSFET
OUT
pin. When enabled, V
capacitor will be allowed to
OUT
has charged to within
OUT
. As soon as
OUT
voltage.
OUT2
is
The V
with 100mV of hysteresis, making it logic-compatible. If
V
low, V
the V
Note that while V
cuitry for V
from V
on the application and capacitor sizing, since the load on
the V
magnitude higher than 8µA.
VSTORE
The VSTORE output can be used to charge a large storage
capacitor or rechargeable battery after V
regulation. Once V
output will be allowed to charge up to the VAUX voltage.
The storage element on VSTORE can be used to power
the system in the event that the input source is lost, or
is unable to provide the current demanded by the V
V
the LTC3108-1 will automatically draw current from the
storage element. Note that it may take a long time to charge
a large capacitor, depending on the input energy available
and the loading on V
Since the maximum current from VSTORE is limited to a
few milliamps, it can safely be used to trickle-charge NiCd
or NiMH rechargeable batteries for energy storage when
the input voltage is lost. Note that the VSTORE capacitor
cannot supply large pulse currents to V
on V
Short-Circuit Protection
All outputs of the LTC3108-1 are current limited to protect
against short-circuits to ground.
Output Voltage Sequencing
A timing diagram showing the typical charging and
voltage sequencing of the outputs is shown in Figure 1.
Note: time not to scale.
OUT2_EN
OUT2
OUT
OUT2
OUT2
OUT2
OUT2
OUT
and LDO outputs. If VAUX drops below VSTORE,
must be handled by the V
(which has an internal pull-down resistor) is
. This added current draw has a negligible effect
output.
output, when enabled, is likely to be orders of
will be off. Driving V
OUT2
enable input has a typical threshold of 1V
draws an extra 8µA of quiescent current
OUT2_EN
OUT
OUT
has reached regulation, the VSTORE
and VLDO.
is high, the current limiting cir-
OUT2_EN
OUT
OUT
capacitor.
high will turn on
OUT
. Any pulse load
has reached
OUT
31081f
,