LTC3588EDD-2#TRPBF Linear Technology, LTC3588EDD-2#TRPBF Datasheet - Page 12

• Manufacturer Part Number: LTC3588EDD-2#TRPBF
• Description: IC ENERGY HARVESTING PSU 10DFN
• Manufacturer: Linear Technology

Specifications of LTC3588EDD-2#TRPBF

• Applications: Energy Harvesting
• Current - Supply: 950nA
• Voltage - Supply: 2.7 V ~ 20 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

APPLICATIONS INFORMATION
LTC3588-2
effect during this time. For applications where the output
must reach regulation on a single UVLO cycle, the energy
required to charge the output capacitor must be taken into
account when sizing C
The duration for which the regulator sleeps depends on
the load current and the size of the output capacitor. The
sleep time decreases as the load current increases and/or
as the output capacitor decreases. The DC sleep hysteresis
window is ±16mV around the programmed output volt-
age. Ideally this means that the sleep time is determined
by the following equation:
This is true for output capacitors on the order of 100μF
or larger, but as the output capacitor decreases towards
10μF delays in the internal sleep comparator along with
the load current may result in the V
past the ±16mV thresholds. This will lengthen the sleep
time and increase V
is not recommended as V
undesirable level.
If transient load currents above 100mA are required then a
larger capacitor can be used at the output. This capacitor
will be continuously discharged during a load condition
and the capacitor can be sized for an acceptable drop in
V
Here V
and V
average current being delivered from the buck converter,
typically I
A standard surface mount ceramic capacitor can be used
for C
to a low leakage aluminum electrolytic capacitor or a
supercapacitor. These capacitors can be obtained from
manufacturers such as Vishay, Illinois Capacitor, AVX,
or CAP-XX.
12
OUT
C
t
SLEEP
OUT
OUT
:
OUT–
OUT+
, though some applications may be better suited
= V
PEAK
= C
(
is the desired lower limit of V
is the value of V
OUT+
OUT
/2.
32mV
I
− V
LOAD
OUT
OUT–
IN
ripple. A capacitor less than 10μF
.
OUT
)
I
OUT
LOAD
ripple could increase to an
t
when PGOOD goes high
LOAD
−I
BUCK
OUT
OUT
voltage slewing
. I
BUCK
is the
Inductor
The buck is optimized to work with a 22μH inductor. Induc-
tor values greater than 22μH may yield benefi ts in some
applications. For example, a larger inductor will benefi t high
voltage applications by increasing the on-time of the PMOS
switch and improving effi ciency by reducing gate charge
loss. Choose an inductor with a DC current rating greater
than 350mA. The DCR of the inductor can have an impact
on effi ciency as it is a source of loss. Trade-offs between
price, size, and DCR should be evaluated. Table 3 lists
several inductors that work well with the LTC3588-2.
Table 3. Recommended Inductors for LTC3588-2
INDUCTOR
TYPE
A997AS-220M
LPS5030-223MLC
LPS4012-473MLC
SLF7045T
V
A 1μF capacitor should be connected between V
CAP and a 4.7μF capacitor should be connected between
V
during buck switching and compensate the internal rail
generation circuits.
Additional Applications with Piezo Inputs
The versatile LTC3588-2 can be used in a variety of con-
fi gurations. Figure 6 shows a single piezo source powering
two LTC3588-2s simultaneously, providing capability for
multiple rail systems. As the piezo provides input power
both V
output starts drawing power, only its corresponding V
will fall as the bridges of each LTC3588-2 provide isola-
tion. Input piezo energy will then be directed to this lower
voltage capacitor until both V
confi guration is expandable to any number of LTC3588-2s
powered by a single piezo as long as the piezo can sup-
port the sum total of the quiescent currents from each
LTC3588-2.
IN2
IN2
and CAP Capacitors
and GND. These capacitors hold up the internal rails
IN
rails will initially come up together, but when one
(μH)
100
22
22
47
L
(mA)
MAX
390
700
350
500
I
DC
0.440 4.0 × 4.0 × 1.8
0.190 4.9 × 4.9 × 3.0
1.400 4.0 × 4.0 × 1.2
0.250 7.0 × 7.0 × 4.8
MAX
DCR
(Ω)
IN
rails are again equal. This
(L × W × H)
SIZE in mm
FACTURER
Coilcraft
Coilcraft
MANU-
Toko
TDK
IN
35882f
and
IN