LTC3588-1
1
35881fc
For more information www.linear.com/LTC3588-1
TYPICAL APPLICATION
DESCRIPTION
Nanopower Energy
Harvesting Power Supply
The LT C
®
3588-1 integrates a low-loss full-wave bridge
rectifier with a high efficiency buck converter to form a
complete energy harvesting solution optimized for high
output impedance energy sources such as piezoelectric,
solar, or magnetic transducers. An ultralow quiescent
current undervoltage lockout (UVLO) mode with a wide
hysteresis window allows charge to accumulate on an input
capacitor until the buck converter can efficiently transfer a
portion of the stored charge to the output. In regulation,
the LTC3588-1 enters a sleep state in which both input and
output quiescent currents are minimal. The buck converter
turns on and off as needed to maintain regulation.
Four output voltages, 1.8V, 2.5V, 3.3V and 3.6V, are pin
selectable with up to 100mA of continuous output current;
however, the output capacitor may be sized to service a
higher output current burst. An input protective shunt set
at 20V enables greater energy storage for a given amount
of input capacitance.
L, LT , LT C , LT M , Linear Technology, the Linear logo and Burst Mode are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
100mA Piezoelectric Energy Harvesting Power Supply
FEATURES
APPLICATIONS
n 950nA Input Quiescent Current (Output in
Regulation – No Load)
n 450nA Input Quiescent Current in UVLO
n 2.7V to 20V Input Operating Range
n Integrated Low-Loss Full-Wave Bridge Rectifier
n Up to 100mA of Output Current
n Selectable Output Voltages of 1.8V, 2.5V, 3.3V, 3.6V
n High Efficiency Integrated Hysteretic Buck DC/DC
n Input Protective Shunt – Up to 25mA Pull-Down at
VIN ≥ 20V
n Wide Input Undervoltage Lockout (UVLO) Range
n Available in 10-Lead MSE and 3mm × 3mm DFN
Packages
n Piezoelectric Energy Harvesting
n Electro-Mechanical Energy Harvesting
n Wireless HVAC Sensors
n Mobile Asset Tracking
n Tire Pressure Sensors
n Battery Replacement for Industrial Sensors
n Remote Light Switches
n Standalone Nanopower Buck Regulator
35881 TA01
PZ1
VIN
CAP
VIN2
PZ2
SW
VOUT
PGOOD
D0, D1
LTC3588-1
MIDE V21BL
GND
1µF
6V
4.7µF
6V
CSTORAGE
25V
47µF
6V
OUTPUT
VOLTAGE
SELECT
VOUT
10µH
2
LTC3588-1 3.3V Regulator Start-Up Profile
TIME (s)
0
VOLTAGE (V)
22
20
18
8
4
10
12
14
16
6
2
0200
35881 TA01b
600400
VIN
VOUT
PGOOD = LOGIC 1
CSTORAGE = 22µF, COUT = 47µF
NO LOAD, IVIN = 2µA
LTC3588-1
2
35881fc
For more information www.linear.com/LTC3588-1
ABSOLUTE MAXIMUM RATINGS
VIN
Low Impedance Source ....................... –0.3V to 18V*
Current Fed, ISW = 0A ...................................... 25mA†
PZ1, PZ2 ...........................................................0V to VIN
D0, D1 ..............–0.3V to [Lesser of (VIN2 + 0.3V) or 6V]
CAP ......................[Higher of –0.3V or (VIN – 6V)] to VIN
VIN2 ................... –0.3V to [Lesser of (VIN + 0.3V) or 6V]
(Note 1)
TOP VIEW
11
GND
DD PACKAGE
10-LEAD (3mm × 3mm) PLASTIC DFN
10
9
6
7
8
4
5
3
2
1PGOOD
D0
D1
VIN2
VOUT
PZ1
PZ2
CAP
VIN
SW
TJMAX = 125°C, θJA = 43°C/W, θJC = 7.5°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
1
2
3
4
5
PZ1
PZ2
CAP
VIN
SW
10
9
8
7
6
PGOOD
D0
D1
VIN2
VOUT
TOP VIEW
MSE PACKAGE
10-LEAD PLASTIC eMSOP
11
GND
TJMAX = 125°C, θJA = 45°C/W, θJC = 10°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
PIN CONFIGURATION
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3588EDD-1#PBF LTC3588EDD-1#TRPBF LFKY 10-Lead (3mm × 3mm) Plastic DFN –40°C to 125°C
LTC3588IDD-1#PBF LTC3588IDD-1#TRPBF LFKY 10-Lead (3mm × 3mm) Plastic DFN –40°C to 125°C
LTC3588EMSE-1#PBF LTC3588EMSE-1#TRPBF LTFKX 10-Lead Plastic eMSOP –40°C to 125°C
LTC3588IMSE-1#PBF LTC3588IMSE-1#TRPBF LTFKX 10-Lead Plastic eMSOP –40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping
container.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
This product is only offered in trays. For more information go to: http://www.linear.com/packaging/
VOUT ....................–0.3V to Lesser of (VIN2 + 0.3V) or 6V
PGOOD .............. –0.3V to Lesser of (VOUT + 0.3V) or 6V
IPZ1, IPZ2 ............................................................. ±50mA
ISW ...................................................................... 350mA
Operating Junction Temperature Range
(Notes 2, 3) ................................................ –40 to 125°C
Storage Temperature Range ......................–65 to 150°C
Lead Temperature (Soldering, 10 sec)
MSE Only ..........................................................300°C
* VIN has an internal 20V clamp
† For t < 1ms and Duty Cycle < 1%,
Absolute Maximum Continuous Current = 5mA
LTC3588-1
3
35881fc
For more information www.linear.com/LTC3588-1
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are for TA = 25°C. (Note 2) VIN = 5.5V unless otherwise specified.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN Input Voltage Range Low Impedance Source on VIN l18.0 V
IVIN VIN Quiescent Current
UVLO
Buck Enabled, Sleeping
Buck Enabled, Sleeping
Buck Enabled, Not Sleeping
VIN = 2.5V, Not PGOOD
VIN = 4.5V
VIN = 18V
ISW = 0A (Note 4)
450
950
1.7
150
700
1500
2.5
250
nA
nA
µA
µA
VUVLO VIN Undervoltage Lockout Threshold VIN Rising
1.8V Output Selected; D1 = 0, D0 = 0
2.5V Output Selected; D1 = 0, D0 = 1
3.3V Output Selected; D1 = 1, D0 = 0
3.6V Output Selected; D1 = 1, D0 = 1
l
l
l
l
3.77
3.77
4.73
4.73
4.04
4.04
5.05
5.05
4.30
4.30
5.37
5.37
V
V
V
V
VIN Falling
1.8V Output Selected; D1 = 0, D0 = 0
2.5V Output Selected; D1 = 0, D0 = 1
3.3V Output Selected; D1 = 1, D0 = 0
3.6V Output Selected; D1 = 1, D0 = 1
l
l
l
l
2.66
2.66
3.42
3.75
2.87
2.87
3.67
4.02
3.08
3.08
3.91
4.28
V
V
V
V
VSHUNT VIN Shunt Regulator Voltage IVIN = 1mA 19.0 20.0 21.0 V
ISHUNT Maximum Protective Shunt Current 1ms Duration 25 mA
Internal Bridge Rectifier Loss
(|VPZ1 – VPZ2| – VIN)
IBRIDGE = 10µA 350 400 450 mV
Internal Bridge Rectifier Reverse
Leakage Current
VREVERSE = 18V 20 nA
Internal Bridge Rectifier Reverse
Breakdown Voltage
IREVERSE = 1µA VSHUNT 30 V
VOUT Regulated Output Voltage 1.8V Output Selected
Sleep Threshold
Wake-Up Threshold
2.5V Output Selected
Sleep Threshold
Wake-Up Threshold
3.3V Output Selected
Sleep Threshold
Wake-Up Threshold
3.6V Output Selected
Sleep Threshold
Wake-Up Threshold
l
l
l
l
l
l
l
l
1.710
2.425
3.201
3.492
1.812
1.788
2.512
2.488
3.312
3.288
3.612
3.588
1.890
2.575
3.399
3.708
V
V
V
V
V
V
V
V
PGOOD Falling Threshold As a Percentage of the Selected VOUT 83 92 %
IVOUT Output Quiescent Current VOUT = 3.6V 89 150 nA
IPEAK Buck Peak Switch Current 200 260 350 mA
IBUCK Available Buck Output Current 100 mA
RPBuck PMOS Switch On-Resistance 1.1 Ω
RNBuck NMOS Switch On-Resistance 1.3 Ω
Max Buck Duty Cycle l100 %
VIH(D0, D1) D0/D1 Input High Voltage l1.2 V
VIL(D0, D1) D0/D1 Input Low Voltage l0.4 V
IIH(D0, D1) D0/D1 Input High Current 10 nA
IIL(D0, D1) D0/D1 Input Low Current 10 nA
LTC3588-1
4
35881fc
For more information www.linear.com/LTC3588-1
TYPICAL PERFORMANCE CHARACTERISTICS
IVIN in UVLO vs VIN IVIN in Sleep vs VIN UVLO Rising vs Temperature
UVLO Falling vs Temperature VSHUNT vs Temperature
Total Bridge Rectifier Drop
vs Bridge Current
TEMPERATURE (°C)
–55
UVLO RISING (V)
5.2
5.0
4.6
4.2
4.8
4.4
4.0
3.8 25 105–15 65
35881 G03
1255 85–35 45
D1 = D0 = 1
D1 = D0 = 0
TEMPERATURE (°C)
–55
UVLO FALLING (V)
4.2
4.0
3.6
3.2
3.8
3.4
3.0
2.8 25 105–15 65
35881 G04
1255 85–35 45
D1 = D0 = 1
D1 = D0 = 0
D1 = 1, D0 = 0
BRIDGE CURRENT (A)
V
BRIDGE
(mV)
35881 G06
1800
1600
1400
1200
1000
800
600
400
200
01µ 10µ 10m1m100µ
85°C
25°C
–40°C
|VPZ1 – VPZ2| – VIN
VIN (V)
0
IVIN (nA)
1000
900
700
500
800
600
400
300
200
100
04 52
35881 G01
631
D1 = D0 = 1
85°C
25°C
–40°C
VIN (V)
2
I
VIN
(nA)
2400
2200
1800
1400
2000
1600
1200
1000
800
600
400 148 10 16
35881 G02
181264
D1 = D0 = 0
85°C
25°C
–40°C
TEMPERATURE (°C)
–55
V
SHUNT
(V)
21.0
20.8
20.4
20.0
20.6
20.2
19.6
19.8
19.4
19.2
19.0 655 25 85 105
35881 G05
12545–15–35
ISHUNT = 25mA
ISHUNT = 1mA
ELECTRICAL CHARACTERISTICS
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTC3588-1 is tested under pulsed load conditions such
that TJ ≈ TA. The LTC3588E-1 is guaranteed to meet specifications
from 0°C to 85°C junction temperature. Specifications over the –40°C
to 125°C operating junction temperature range are assured by design,
characterization, and correlation with statistical process controls.
The LTC3588I-1 is guaranteed over the full –40°C to 125°C operating
junction temperature range. Note that the maximum ambient temperature
consistent with these specifications is determined by specific operating
conditions in conjunction with board layout, the rated package thermal
impedance and other environmental factors.
Note 3: The junction temperature (TJ, in °C) is calculated from the ambient
temperature (TA, in °C) and power dissipation (PD, in Watts) according
to the formula: TJ = TA + (PD • θJA), where θJA (in °C/W) is the package
thermal impedance.
Note 4: Dynamic supply current is higher due to gate charge being
delivered at the switching frequency.
LTC3588-1
5
35881fc
For more information www.linear.com/LTC3588-1
TYPICAL PERFORMANCE CHARACTERISTICS
3.6V Output vs Temperature
VOUT Load Regulation VOUT Line Regulation
1.8V Output vs Temperature
2.5V Output vs Temperature 3.3V Output vs Temperature
TEMPERATURE (°C)
–55
V
OUT
(V)
1.85
1.80
1.70
1.75
1.65
1.60 25 105–15 65
35881 G09
1255 85–35 45
SLEEP THRESHOLD
WAKE-UP THRESHOLD
PGOOD FALLING
TEMPERATURE (°C)
–55
VOUT (V)
2.55
2.50
2.35
2.45
2.30
2.40
2.25 25 105–15 65
35881 G10
1255 85–35 45
SLEEP THRESHOLD
WAKE-UP THRESHOLD
PGOOD FALLING
TEMPERATURE (°C)
–55
VOUT (V)
3.35
3.30
3.15
3.05
3.25
3.10
3.20
3.00 25 105–15 65
35881 G11
1255 85–35 45
SLEEP THRESHOLD
WAKE-UP THRESHOLD
PGOOD FALLING
TEMPERATURE (°C)
–55
V
OUT
(V)
3.65
3.55
3.40
3.30
3.50
3.60
3.35
3.45
3.25 25 105–15 65
35881 G12
1255 85–35 45
SLEEP THRESHOLD
WAKE-UP THRESHOLD
PGOOD FALLING
LOAD CURRENT (A)
V
OUT
(V)
35881 G13
2.56
2.54
2.46
2.48
2.50
2.52
2.441µ 10µ 10m 100m1m100µ
VIN = 5V, L = 10µH, D1 = 0, D0 = 1
VIN (V)
V
OUT
(V)
35881 G14
2.56
2.54
2.46
2.48
2.50
2.52
2.44 4 6 16 18148 10 12
L = 10µH, ILOAD = 100mA, D1 = 0, D0 = 1
IVOUT vs Temperature
TEMPERATURE (°C)
–55
I
VOUT
(nA)
120
100
70
60
50
30
90
110
40
80
20 25 105–15 65
35881 G15
1255 85–35 45
VOUT = 3.6V
VOUT = 3.3V
VOUT = 2.5V
VOUT = 1.8V
TEMPERATURE (°C)
–55
BRIDGE LEAKAGE (nA)
20
18
14
10
16
12
6
8
4
2
08035 125
35881 G07
170–10
VIN = 18V, LEAKAGE AT PZ1 OR PZ2
Bridge Leakage vs Temperature Bridge Frequency Response
FREQUENCY (Hz)
VIN (V)
35881 G08
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
010 100 100M10M1M10k1k 100k
4VP-P APPLIED TO PZ1/PZ2 INPUT
MEASURED IN UVLO
LTC3588-1
6
35881fc
For more information www.linear.com/LTC3588-1
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs VIN for
ILOAD = 100mA, L = 100µH
Efficiency vs VIN for
VOUT = 3.3V, L = 100µH
Efficiency vs VIN for
ILOAD = 100mA, L = 10µH
Efficiency vs VIN for
VOUT = 3.3V, L = 10µH
VIN (V)
EFFICIENCY (%)
35881 G20
100
90
50
60
70
80
40 2 10864 16 181412
VOUT = 1.8V
VOUT = 2.5V
VOUT = 3.3V
VOUT = 3.6V
VIN (V)
EFFICIENCY (%)
35881 G21
95
85
45
55
65
75
35 4 1086 16 181412
ILOAD = 10µA
ILOAD = 30µA
ILOAD = 50µA
ILOAD = 100µA
ILOAD = 100mA
Efficiency vs ILOAD, L = 100µH
LOAD CURRENT (A)
EFFICIENCY (%)
35881 G22
100
90
10
20
30
80
70
60
50
40
0
VIN = 5V
VOUT = 1.8V
VOUT = 2.5V
VOUT = 3.3V
VOUT = 3.6V
1µ 10µ 10m 100m1m100µ
VIN (V)
EFFICIENCY (%)
35881 G23
100
90
80
70
60
50
40 2 864 1810 12 14 16
VOUT = 1.8V
VOUT = 2.5V
VOUT = 3.3V
VOUT = 3.6V
VIN (V)
EFFICIENCY (%)
35881 G24
95
85
45
55
65
75
35 4 1086 16 181412
ILOAD = 10µA
ILOAD = 30µA
ILOAD = 50µA
ILOAD = 100µA
ILOAD = 100mA
Efficiency vs ILOAD, L = 10µH
LOAD CURRENT (A)
EFFICIENCY (%)
35881 G19
100
90
30
40
50
60
70
80
20
10
01µ 10µ 10m 100m1m100µ
VIN = 5V
VOUT = 1.8V
VOUT = 2.5V
VOUT = 3.3V
VOUT = 3.6V
IPEAK vs Temperature
RDS(ON) of PMOS/NMOS
vs Temperature
TEMPERATURE (°C)
–55
IPEAK (mA)
300
280
250
240
230
210
270
290
220
260
200 25 105–15 65
35881 G16
1255 85–35 45
TEMPERATURE (°C)
–55
R
DS(ON)
(Ω)
2.0
1.6
1.0
1.4
1.8
1.2
0.8 25 105–15 65
35881 G17
1255 85–35 45
PMOS
NMOS
Operating Waveforms
5µs/DIV
OUTPUT
VOLTAGE
50mV/DIV
AC-COUPLED
INDUCTOR
CURRENT
200mA/DIV
VIN = 5V, VOUT = 3.3V
ILOAD = 1mA
L = 10µH, C
OUT
= 47µF
SWITCH
VOLTAGE
2V/DIV
0mA
0V
35881 G18
LTC3588-1
7
35881fc
For more information www.linear.com/LTC3588-1
PIN FUNCTIONS
PZ1 (Pin 1): Input connection for piezoelectric element or
other AC source (used in conjunction with PZ2).
PZ2 (Pin 2): Input connection for piezoelectric element or
other AC source (used in conjunction with PZ1).
CAP (Pin 3): Internal rail referenced to VIN to serve as gate
drive for buck PMOS switch. A 1µF capacitor should be
connected between CAP and VIN. This pin is not intended
for use as an external system rail.
VIN (Pin 4): Rectified Input Voltage. A capacitor on this
pin serves as an energy reservoir and input supply for the
buck regulator. The VIN voltage is internally clamped to a
maximum of 20V (typical).
SW (Pin 5): Switch Pin for the Buck Switching Regulator.
A 10µH or larger inductor should be connected from SW
to VOUT.
VOUT (Pin 6): Sense pin used to monitor the output volt-
age and adjust it through internal feedback.
VIN2 (Pin 7): Internal low voltage rail to serve as gate drive
for buck NMOS switch. Also serves as a logic high rail for
output voltage select bits D0 and D1. A 4.7µF capacitor
should be connected from VIN2 to GND. This pin is not
intended for use as an external system rail.
D1 (Pin 8): Output Voltage Select Bit. D1 should be tied
high to VIN2 or low to GND to select desired VOUT (see
Table 1).
D0 (Pin 9): Output Voltage Select Bit. D0 should be tied
high to VIN2 or low to GND to select desired VOUT (see
Table 1).
PGOOD (Pin 10): Power good output is logic high when
VOUT is above 92% of the target value. The logic high is
referenced to the VOUT rail.
GND (Exposed Pad Pin 11): Ground. The Exposed Pad
should be connected to a continuous ground plane on the
second layer of the printed circuit board by several vias
directly under the LTC3588-1.
BLOCK DIAGRAM
35881 BD
D1, D0
PZ2
PZ1
VIN
UVLO BUCK
CONTROL
INTERNAL RAIL
GENERATION
2
BANDGAP
REFERENCE
SLEEP
PGOOD
COMPARATOR
CAP
SW
GND
PGOOD
VIN2
VOUT
20V
5
3
7
11
10
6
8, 9
2
1
4
LTC3588-1
8
35881fc
For more information www.linear.com/LTC3588-1
The LTC3588-1 is an ultralow quiescent current power
supply designed specifically for energy harvesting and/or
low current step-down applications. The part is designed to
interface directly to a piezoelectric or alternative A/C power
source, rectify a voltage waveform and store harvested
energy on an external capacitor, bleed off any excess power
via an internal shunt regulator, and maintain a regulated
output voltage by means of a nanopower high efficiency
synchronous buck regulator.
Internal Bridge Rectifier
The LTC3588-1 has an internal full-wave bridge rectifier
accessible via the differential PZ1 and PZ2 inputs that
rectifies AC inputs such as those from a piezoelectric
element. The rectified output is stored on a capacitor at
the VIN pin and can be used as an energy reservoir for the
buck converter. The low-loss bridge rectifier has a total
drop of about 400mV with typical piezo generated currents
(~10µA). The bridge is capable of carrying up to 50mA.
One side of the bridge can be operated as a single-ended
DC input. PZ1 and PZ2 should never be shorted together
when the bridge is in use.
Undervoltage Lockout (UVLO)
When the voltage on VIN rises above the UVLO rising
threshold the buck converter is enabled and charge is
transferred from the input capacitor to the output capaci-
tor. A wide (~1V) UVLO hysteresis window is employed
with a lower threshold approximately 300mV above the
selected regulated output voltage to prevent short cycling
during buck power-up. When the input capacitor voltage
is depleted below the UVLO falling threshold the buck
converter is disabled. Extremely low quiescent current
(450nA typical) in UVLO allows energy to accumulate on
the input capacitor in situations where energy must be
harvested from low power sources.
Internal Rail Generation
Two internal rails, CAP and VIN2, are generated from VIN and
are used to drive the high side PMOS and low side NMOS
of the buck converter, respectively. Additionally the VIN2
rail serves as logic high for output voltage select bits D0
and D1. The VIN2 rail is regulated at 4.8V above GND while
the CAP rail is regulated at 4.8V below VIN. These are not
intended to be used as external rails. Bypass capacitors
are connected to the CAP and VIN2 pins to serve as energy
reservoirs for driving the buck switches. When VIN is below
4.8V, VIN2 is equal to VIN and CAP is held at GND. Figure 1
shows the ideal VIN, VIN2 and CAP relationship.
Figure 1. Ideal VIN, VIN2 and CAP Relationship
OPERATION
Buck Operation
The buck regulator uses a hysteretic voltage algorithm to
control the output through internal feedback from the VOUT
sense pin. The buck converter charges an output capaci-
tor through an inductor to a value slightly higher than the
regulation point. It does this by ramping the inductor current
up to 260mA through an internal PMOS switch and then
ramping it down to 0mA through an internal NMOS switch.
This efficiently delivers energy to the output capacitor. The
ramp rate is determined by VIN, VOUT, and the inductor value.
If the input voltage falls below the UVLO falling threshold
VIN (V)
0
VOLTAGE (V)
18
12
14
16
10
2
4
8
6
0105
35881 F01
15
VIN
VIN2
CAP
LTC3588-1
9
35881fc
For more information www.linear.com/LTC3588-1
OPERATION
before the output voltage reaches regulation, the buck
converter will shut off and will not be turned on until the
input voltage again rises above the UVLO rising threshold.
During this time the output voltage will be loaded by less
than 100nA. When the buck brings the output voltage into
regulation the converter enters a low quiescent current
sleep state that monitors the output voltage with a sleep
comparator. During this operating mode load current is
provided by the buck output capacitor. When the output
voltage falls below the regulation point the buck regulator
wakes up and the cycle repeats. This hysteretic method
of providing a regulated output reduces losses associated
with FET switching and maintains an output at light loads.
The buck delivers a minimum of 100mA of average load
current when it is switching.
When the sleep comparator signals that the output has
reached the sleep threshold the buck converter may be
in the middle of a cycle with current still flowing through
the inductor. Normally both synchronous switches would
turn off and the current in the inductor would freewheel
to zero through the NMOS body diode. The LTC3588-1
keeps the NMOS switch on during this time to prevent the
conduction loss that would occur in the diode if the NMOS
were off. If the PMOS is on when the sleep comparator
trips the NMOS will turn on immediately in order to ramp
down the current. If the NMOS is on it will be kept on until
the current reaches zero.
Though the quiescent current when the buck is switching
is much greater than the sleep quiescent current, it is still
a small percentage of the average inductor current which
results in high efficiency over most load conditions. The
buck operates only when sufficient energy has been ac-
cumulated in the input capacitor and the length of time the
converter needs to transfer energy to the output is much
less than the time it takes to accumulate energy. Thus, the
buck operating quiescent current is averaged over a long
period of time so that the total average quiescent current
is low. This feature accommodates sources that harvest
small amounts of ambient energy.
Four selectable voltages are available by tying the output
select bits, D0 and D1, to GND or VIN2. Table 1 shows the
four D0/D1 codes and their corresponding output voltages.
Table 1. Output Voltage Selection
D1 D0 VOUT VOUT QUIESCENT CURRENT (IVOUT)
0 0 1.8V 44nA
0 1 2.5V 62nA
1 0 3.3V 81nA
1 1 3.6V 89nA
The internal feedback network draws a small amount of
current from VOUT as listed in Table 1.
Power Good Comparator
A power good comparator produces a logic high referenced
to VOUT on the PGOOD pin the first time the converter
reaches the sleep threshold of the programmed VOUT,
signaling that the output is in regulation. The PGOOD pin
will remain high until VOUT falls to 92% of the desired
regulation voltage. Several sleep cycles may occur during
this time. Additionally, if PGOOD is high and VIN falls below
the UVLO falling threshold, PGOOD will remain high until
VOUT falls to 92% of the desired regulation point. This
allows output energy to be used even if the input is lost.
Figure 2 shows the behavior for VOUT = 3.6V and no load.
At t = 75s VIN becomes high impedance and is discharged
by the quiescent current of the LTC3588-1 and through
servicing VOUT which is discharged by its own leakage
current. VIN crosses UVLO falling but PGOOD remains high
until VOUT decreases to 92% of the desired regulation point.
The PGOOD pin is designed to drive a microprocessor or
other chip I/O and is not intended to drive higher current
loads such as an LED.
TIME (s)
0
VOLTAGE (V)
6
3
4
5
2
1
0200100
35881 F02
300
VIN
VIN = UVLO FALLING
VOUT
PGOOD
CVIN = CVOUT = 100µF
Figure 2. PGOOD Operation During Transition to UVLO
LTC3588-1
10
35881fc
For more information www.linear.com/LTC3588-1
OPERATION
The D0/D1 inputs can be switched while in regulation as
shown in Figure 3. If VOUT is programmed to a voltage with
a PGOOD falling threshold above the old VOUT, PGOOD will
transition low until the new regulation point is reached.
When VOUT is programmed to a lower voltage, PGOOD
will remain high through the transition.
Energy Storage
Harvested energy can be stored on the input capacitor
or the output capacitor. The wide input range takes ad-
vantage of the fact that energy storage on a capacitor is
proportional to the square of the capacitor voltage. After
the output voltage is brought into regulation any excess
energy is stored on the input capacitor and its voltage
increases. When a load exists at the output the buck can
efficiently transfer energy stored at a high voltage to the
regulated output. While energy storage at the input utilizes
the high voltage at the input, the load current is limited
to what the buck converter can supply. If larger loads
need to be serviced the output capacitor can be sized to
support a larger current for some duration. For example,
a current burst could begin when PGOOD goes high and
would continuously deplete the output capacitor until
PGOOD went low.
Figure 3. PGOOD Operation During D0/D1 Transition
TIME (ms)
0
VOUT VOLTAGE (V)
5
4
3
2
1
018161412108642
35881 F03
20
COUT = 100µF, ILOAD = 100mA
VOUT
D1=D0=0
PGOOD = LOGIC1
D1=D0=1 D1=D0=0
LTC3588-1
11
35881fc
For more information www.linear.com/LTC3588-1
Introduction
The LTC3588-1 harvests ambient vibrational energy
through a piezoelectric element in its primary application.
Common piezoelectric elements are PZT (lead zirconate
titanate) ceramics, PVDF (polyvinylidene fluoride) poly-
mers, or other composites. Ceramic piezoelectric elements
exhibit a piezoelectric effect when the crystal structure
of the ceramic is compressed and internal dipole move-
ment produces a voltage. Polymer elements comprised
of long-chain molecules produce a voltage when flexed
as molecules repel each other. Ceramics are often used
under direct pressure while a polymer can be flexed more
readily. A wide range of piezoelectric elements are avail-
able and produce a variety of open-circuit voltages and
short-circuit currents. Typically the open-circuit voltage
and short-circuit currents increase with available vibra-
tional energy as shown in Figure 4. Piezoelectric elements
can be placed in series or in parallel to achieve desired
open-circuit voltages.
APPLICATIONS INFORMATION
The LTC3588-1 is well-suited to a piezoelectric energy
harvesting application. The 20V input protective shunt
can accommodate a variety of piezoelectric elements. The
low quiescent current of the LTC3588-1 enables efficient
energy accumulation from piezoelectric elements which
can have short-circuit currents on the order of tens of
microamps. Piezoelectric elements can be obtained from
manufacturers listed in Table 2.
Table 2. Piezoelectric Element Manufacturers
Advanced Cerametrics www.advancedcerametrics.com
Piezo Systems www.piezo.com
Measurement Specialties www.meas-spec.com
PI (Physik Instrumente) www.pi-usa.us
MIDE Technology Corporation www.mide.com
Morgan Technical Ceramics www.morganelectroceramics.com
The LTC3588-1 will gather energy and convert it to a use-
able output voltage to power microprocessors, wireless
sensors, and wireless transmission components. Such a
wireless sensor application may require much more peak
power than a piezoelectric element can produce. However,
the LTC3588-1 accumulates energy over a long period of
time to enable efficient use for short power bursts. For
continuous operation, these bursts must occur with a low
duty cycle such that the total output energy during the burst
does not exceed the average source power integrated over
an energy accumulation cycle. For piezoelectric inputs the
time between cycles could be minutes, hours, or longer
depending on the selected capacitor values and the nature
of the vibration source.
Figure 4. Typical Piezoelectric Load Lines
for Piezo Systems T220-A4-503X
PIEZO CURRENT (µA)
0
PIEZO VOLTAGE (V)
12
9
6
3
02010
35881 F04
30
INCREASING
VIBRATION ENERGY
LTC3588-1
12
35881fc
For more information www.linear.com/LTC3588-1
APPLICATIONS INFORMATION
PGOOD Signal
The PGOOD signal can be used to enable a sleeping
microprocessor or other circuitry when VOUT reaches
regulation, as shown in Figure 5. Typically VIN will be
somewhere between the UVLO thresholds at this time
and a load could only be supported by the output capaci-
tor. Alternatively, waiting a period of time after PGOOD
goes high would let the input capacitor accumulate more
energy allowing load current to be maintained longer as
the buck efficiently transfers that energy to the output.
While active, a microprocessor may draw a small load
when operating sensors, and then draw a large load to
transmit data. Figure 5 shows the LTC3588-1 responding
smoothly to such a load step.
Input and Output Capacitor Selection
The input and output capacitors should be selected based
on the energy needs and load requirements of the ap-
plication. In every case the VIN capacitor should be rated
to withstand the highest voltage ever present at VIN.
For 100mA or smaller loads, storing energy at the input
takes advantage of the high voltage input since the buck
can deliver 100mA average load current efficiently to the
output. The input capacitor should then be sized to store
enough energy to provide output power for the length of
time required. This may involve using a large capacitor,
letting VIN charge to a high voltage, or both. Enough energy
should be stored on the input so that the buck does not
reach the UVLO falling threshold which would halt energy
transfer to the output. In general:
PLOADtLOAD =
1
2ηCIN VIN2−VUVLOFALLING2
()
V
UVLOFALLING
≤V
IN
≤V
SHUNT
The above equation can be used to size the input capaci-
tor to meet the power requirements of the output for the
desired duration. Here η is the average efficiency of the
buck converter over the input range and VIN is the input
voltage when the buck begins to switch. This equation
may overestimate the input capacitor necessary since load
current can deplete the output capacitor all the way to the
lower PGOOD threshold. It also assumes that the input
source charging has a negligible effect during this time.
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 ±12mV around the programmed output volt-
age. Ideally this means that the sleep time is determined
by the following equation:
tSLEEP =COUT
24mV
I
LOAD
35881 F05a 35881 F05b
PZ1
VIN
CAP
VIN2
D1
D0
PZ2
PGOOD
SW
VOUT
LTC3588-1
MICROPROCESSOR
GND
1µF
6V
4.7µF
6V
10µF
25V
47µF
6V
10µH 3.3V
EN
CORE GND
TX
250µs/DIV
VIN = 5V
L = 10µH, COUT = 47µF
LOAD STEP BETWEEN 5mA and 55mA
OUTPUT
VOLTAGE
20mV/DIV
AC-COUPLED
LOAD
CURRENT
25mA/DIV
5mA
MIDE V21BL
Figure 5. 3.3V Piezoelectric Energy Harvester Powering a Microprocessor
with a Wireless Transmitter and 50mA Load Step Response
LTC3588-1
13
35881fc
For more information www.linear.com/LTC3588-1
APPLICATIONS INFORMATION
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 VOUT voltage slewing
past the ±12mV thresholds. This will lengthen the sleep
time and increase VOUT ripple. A capacitor less than 10µF
is not recommended as VOUT ripple could increase to an
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 VOUT:
COUT = (ILOAD – IBUCK )
t
LOAD
V
OUT
+– V
OUT
–
Here VOUT+ is the value of VOUT when PGOOD goes high
and VOUT– is the desired lower limit of VOUT. IBUCK is the
average current being delivered from the buck converter,
typically IPEAK/2.
A standard surface mount ceramic capacitor can be used
for COUT, though some applications may be better suited
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.
Inductor
The buck is optimized to work with an inductor in the
range of 10µH to 22µH, although inductor values outside
this range may yield benefits in some applications. For
typical applications, a value of 10µH is recommended. A
larger inductor will benefit high voltage applications by
increasing the on-time of the PMOS switch and improv-
ing efficiency 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 efficiency 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 LTC3588-1.
Table 3. Recommended Inductors for LTC3588-1
INDUCTOR
TYPE
L
(µH)
MAX
IDC
(mA)
MAX
DCR
(Ω)
SIZE in mm
(L × W × H)
MANU-
FACTURER
CDRH2D18/LDNP 10 430 0.180 3 × 3 × 2 Sumida
107AS-100M 10 650 0.145 2.8 × 3 × 1.8 Toko
EPL3015-103ML 10 350 0.301 2.8 × 3 × 1.5 Coilcraft
MLP3225s100L 10 1000 0.130 3.2 × 2.5 × 1.0 TDK
XLP2010-163ML 10 490 0.611 2.0 × 1.9 × 1.0 Coilcraft
SLF7045T 100 500 0.250 7.0 × 7.0 × 4.5 TDK
VIN2 and CAP Capacitors
A 1μF capacitor should be connected between VIN and
CAP and a 4.7µF capacitor should be connected between
VIN2 and GND. These capacitors hold up the internal rails
during buck switching and compensate the internal rail
generation circuits. In applications where the input source
is limited to less than 6V, the CAP pin can be tied to GND
and the VIN2 pin can be tied to VIN as shown in Figure 6.
An optional 5.6V Zener diode can be connected to VIN to
clamp VIN in this scenario. The leakage of the Zener diode
below its Zener voltage should be considered as it may be
comparable to the quiescent current of the LTC3588-1.
This circuit does not require the capacitors on VIN2 and
CAP, saving components and allowing a lower voltage
rating for the single VIN capacitor.
Figure 6. Smallest Solution Size 1.8V Low Voltage Input
Piezoelectric Power Supply
35881 F06
PZ1
VIN
VIN2
CAP
D1
D0
PZ2
PGOOD
SW
VOUT
LTC3588-1
GND
10µF
6V
10µH VOUT
1.8V
PGOOD
10µF
6V
5.6V
(OPTIONAL)
MIDE V21BL
LTC3588-1
14
35881fc
For more information www.linear.com/LTC3588-1
APPLICATIONS INFORMATION
Figure 8. Piezo Energy Harvester with Battery Backup
Additional Applications with Piezo Inputs
The versatile LTC3588-1 can be used in a variety of con-
figurations. Figure 7 shows a single piezo source powering
two LTC3588-1s simultaneously, providing capability for
multiple rail systems. This setup features automatic sup-
ply sequencing as the LTC3588-1 with the lower voltage
output (i.e. lower UVLO rising threshold) will come up first.
As the piezo provides input power both VIN rails will initially
come up together, but when one output starts drawing
power, only its corresponding VIN will fall as the bridges
of each LTC3588-1 provide isolation. Input piezo energy
will then be directed to this lower voltage capacitor until
both VIN rails are again equal. This configuration is expand-
able to any number of LTC3588-1s powered by a single
piezo as long as the piezo can support the sum total of
the quiescent currents from each LTC3588-1.
A piezo powered LTC3588-1 can also be used in concert
with a battery connected to VIN to supplement the system
if ambient vibrational energy ceases as shown in Figure 8.
A blocking diode placed in series with the battery to
VIN prevents reverse current in the battery if the piezo
source charges VIN past the battery voltage. A 9V battery
is shown, but any stack of batteries of a given chemistry
can be used as long as the battery stack voltage does not
exceed 18V. In this setup the presence of the piezo energy
harvester can greatly increase the life of the battery. If the
piezo source is removed the LTC3588-1 can serve as a
standalone nanopower buck converter. In this case the
bridge is unused and the blocking diode is unnecessary.
Figure 7. Dual Rail Power Supply with Single Piezo and
Automatic Supply Sequencing
35881 F07
PZ1
VIN
CAP
VIN2
D1
D0
PZ2
PGOOD
SW
VOUT
LTC3588-1
GND
10µF
6V
10µF
6V
10µH10µH
1.8V
3.6V
PGOOD2PGOOD1
1µF
6V
PZ2
VIN
CAP
VIN2
D1
D0
PZ1
PGOOD
SW
VOUT
LTC3588-1
GND
4.7µF
6V
1µF
6V
4.7µF
6V
10µF
25V
10µF
25V
MIDE V25W
35881 F08
PZ1
VIN
CAP
VIN2
D1
D0
PZ2
PGOOD
SW
VOUT
LTC3588-1
PIEZO SYSTEMS T220-A4-503X
IR05H40CSPTR
GND
47µF
6V
10µH VOUT
3.3V
PGOOD
100µF
16V
9V
BATTERY
1µF
6V
4.7µF
6V
LTC3588-1
15
35881fc
For more information www.linear.com/LTC3588-1
Figure 9. AC Line Powered 3.6V Buck Regulator with
Large Output Capacitor to Support Heavy Loads
35881 F09
PZ1
VIN
CAP
VIN2
D1
D0
PZ2
PGOOD
SW
VOUT
LTC3588-1
DANGER! HIGH VOLTAGE!
GND
150k
100µF
6V
10µH VOUT
3.6V
PGOOD
10µF
25V
120VAC
60Hz
1µF
6V
4.7µF
6V
150k
150k
150k
DANGEROUS AND LETHAL POTENTIALS ARE PRESENT IN OFFLINE CIRCUITS!
BEFORE PROCEEDING ANY FURTHER, THE READER IS WARNED THAT
CAUTION MUST BE USED IN THE CONSTRUCTION, TESTING AND USE OF
OFFLINE CIRCUITS. EXTREME CAUTION MUST BE USED IN WORKING WITH
AND MAKING CONNECTIONS TO THESE CIRCUITS. REPEAT: OFFLINE
CIRCUITS CONTAIN DANGEROUS, AC LINE-CONNECTED HIGH VOLTAGE
POTENTIALS. USE CAUTION. ALL TESTING PERFORMED ON AN OFFLINE
CIRCUIT MUST BE DONE WITH AN ISOLATION TRANSFORMER CONNECTED
BETWEEN THE OFFLINE CIRCUIT’S INPUT AND THE AC LINE. USERS AND
CONSTRUCTORS OF OFFLINE CIRCUITS MUST OBSERVE THIS PRECAUTION
WHEN CONNECTING TEST EQUIPMENT TO THE CIRCUIT TO AVOID ELECTRIC
SHOCK. REPEAT: AN ISOLATION TRANSFORMER MUST BE CONNECTED
BETWEEN THE CIRCUIT INPUT AND THE AC LINE IF ANY TEST EQUIPMENT IS
TO BE CONNECTED.
APPLICATIONS INFORMATION
Alternate Power Sources
The LTC3588-1 is not limited to use with piezoelectric ele-
ments but can accommodate a wide variety of input sources
depending on the type of ambient energy available. Figure 9
shows the LTC3588-1 internal bridge rectifier connected
to the AC line in series with four 150k current limiting
resistors. This is a high voltage application and minimum
spacing between the line, neutral, and any high voltage
components should be maintained per the applicable UL
specification. For general off-line applications refer to UL
regulation 1012.
Figure 10 shows an application where copper panels are
placed near a standard fluorescent room light to capacitively
Figure 10. Electric Field Energy Harvester
35881 F10
PZ1
VIN
CAP
VIN2
D1
D0
PZ2
PGOOD
SW
VOUT
LTC3588-1
GND
10µF
6V
10µH
3.3V
PGOOD
10µF
25V
1µF
6V
4.7µF
6V
COPPER PANEL
(12" × 24")
COPPER PANEL
(12" × 24")
PANELS ARE PLACED 6"
FROM 2' × 4' FLUORESCENT
LIGHT FIXTURES
harvest energy from the electric field around the light. The
frequency of the emission will be 120Hz for magnetic bal-
lasts but could be higher if the light uses electronic ballast.
The LTC3588-1 bridge rectifier can handle a wide range
of input frequencies.
The LTC3588-1 can also be configured for use with DC
sources such as a solar panel or thermal couple as shown
in Figures 11 and 12 by connecting them to one of the
PZ1/PZ2 inputs. Connecting the two sources in this way
prevents reverse current from flowing in each element.
Current limiting resistors should be used to protect the
PZ1 or PZ2 pins. This can be combined with a battery
backup connected to VIN with a blocking diode.
LTC3588-1
16
35881fc
For more information www.linear.com/LTC3588-1
APPLICATIONS INFORMATION
Figure 11. 5V to 16V Solar-Powered 2.5V Supply with Supercapacitor for
Increased Output Energy Storage and Battery Backup
35881 F11
PZ1
VIN
CAP
VIN2
D0
D1
PZ2
PGOOD
SW
VOUT
LTC3588-1
GND
300Ω
IR05H4OCSPTR
3F
2.7V
10µF
6V NESS SUPER CAPACITOR
ESHSR-0003CO-002R7
10µH VOUT
2.5V
PGOOD
100µF
25V
9V
BATTERY
1µF
6V
4.7µF
6V
5V TO 16V
SOLAR PANEL
+
–
+
35881 F12
PZ1
VIN
CAP
VIN2
D0
D1
PZ2
PGOOD
SW
VOUT
LTC3588-1
GND
47µF
6V
10µH VOUT
2.5V
PGOOD
1µF
16V
1µF
6V
4.7µF
6V
RS, 5.2Ω 100Ω
5.4V
PG-1 THERMAL
GENERATOR
P/N G1-1.0-127-1.27
(TELLUREX)
∆T = 100°C
Figure 12. Thermoelectric Energy Harvester
33881 TA03
PZ1
VIN
CAP
VIN2
D1
D0
PZ2
PGOOD
SW
VOUT
LTC3588-1
GND
10µF
25V 47µF
6V
22µH
1µF
6V
4.7µF
6V
2.2µF
10V
1µF
6V
4.7µF
6V
VIN
CAP
VIN2
EN
D1
D0
PGOOD
SW
VOUT
STBY
LTC3388-3
*
GND
47µF
6V
–3.3V
3.3V
22µH
* EXPOSED PAD MUST BE ELECTRICALLY ISOLATED FROM
SYSTEM GROUND AND CONNECTED TO THE –3.3V RAIL.
Figure 13. Piezoelectric Energy Harvester with ±3.3V Outputs
LTC3588-1
17
35881fc
For more information www.linear.com/LTC3588-1
3.00 ±0.10
(4 SIDES)
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-2).
CHECK THE LTC WEBSITE DATA SHEET FOR CURRENT STATUS OF VARIATION ASSIGNMENT
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE
TOP AND BOTTOM OF PACKAGE
0.40 ± 0.10
BOTTOM VIEW—EXPOSED PAD
1.65 ± 0.10
(2 SIDES)
0.75 ±0.05
R = 0.125
TYP
2.38 ±0.10
(2 SIDES)
15
106
PIN 1
TOP MARK
(SEE NOTE 6)
0.200 REF
0.00 – 0.05
(DD) DFN REV C 0310
0.25 ± 0.05
2.38 ±0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
1.65 ±0.05
(2 SIDES)2.15 ±0.05
0.50
BSC
0.70 ±0.05
3.55 ±0.05
PACKAGE
OUTLINE
0.25 ± 0.05
0.50 BSC
PIN 1 NOTCH
R = 0.20 OR
0.35 × 45°
CHAMFER
DD Package
10-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1699 Rev C)
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
LTC3588-1
18
35881fc
For more information www.linear.com/LTC3588-1
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
MSOP (MSE) 0213 REV I
0.53 ±0.152
(.021 ±.006)
SEATING
PLANE
0.18
(.007)
1.10
(.043)
MAX
0.17 –0.27
(.007 – .011)
TYP
0.86
(.034)
REF
0.50
(.0197)
BSC
1234 5
4.90 ±0.152
(.193 ±.006)
0.497 ±0.076
(.0196 ±.003)
REF
8910
10
1
76
3.00 ±0.102
(.118 ±.004)
(NOTE 3)
3.00 ±0.102
(.118 ±.004)
(NOTE 4)
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
6. EXPOSED PAD DIMENSION DOES INCLUDE MOLD FLASH. MOLD FLASH ON E-PAD
SHALL NOT EXCEED 0.254mm (.010") PER SIDE.
0.254
(.010) 0° – 6° TYP
DETAIL “A”
DETAIL “A”
GAUGE PLANE
5.10
(.201)
MIN
3.20 – 3.45
(.126 – .136)
0.889 ±0.127
(.035 ±.005)
RECOMMENDED SOLDER PAD LAYOUT
1.68 ±0.102
(.066 ±.004)
1.88 ±0.102
(.074 ±.004)
0.50
(.0197)
BSC
0.305 ± 0.038
(.0120 ±.0015)
TYP
BOTTOM VIEW OF
EXPOSED PAD OPTION
1.68
(.066)
1.88
(.074)
0.1016 ±0.0508
(.004 ±.002)
DETAIL “B”
DETAIL “B”
CORNER TAIL IS PART OF
THE LEADFRAME FEATURE.
FOR REFERENCE ONLY
NO MEASUREMENT PURPOSE
0.05 REF
0.29
REF
MSE Package
10-Lead Plastic MSOP, Exposed Die Pad
(Reference LTC DWG # 05-08-1664 Rev I)
LTC3588-1
19
35881fc
For more information www.linear.com/LTC3588-1
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
REVISION HISTORY
REV DATE DESCRIPTION PAGE NUMBER
A 9/10 Updated/added part number on the Piezoelectric Transducer on the front and back page applications, and Figures 5,
6 and 7
Updated Temperature Range in Order Information
Changed TJ = 25°C to TA = 25°C and ILOAD to IBUCK in Electrical Characteristics
Updated Notes 2, 3 and 4
Updated G21 in Typical Performance Characteristics
Added Figure 13
Updated Related Parts
1, 12, 13,
14, 20
2
3
4
6
16
20
B 7/14 Clarified title and Description
Clarified x-axis label on Figure 1
Clarified Figure 8
Clarified Related Parts list
1
8
14
20
C 8/15 Modified COUT Equation 13
LTC3588-1
20
35881fc
For more information www.linear.com/LTC3588-1
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
LINEAR TECHNOLOGY CORPORATION 2010
LT 0815 REV C • PRINTED IN USA
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com/LTC3588-1
RELATED PARTS
TYPICAL APPLICATION
PART NUMBER DESCRIPTION COMMENTS
LT1389 Nanopower Precision Shunt Voltage Reference 800nA Operating Current, 1.25V/2.5V/4.096V
LTC1540 Nanopower Comparator with Reference 0.3µA IQ, Drives 0.01µF, Adjustable Hysteresis, 2V to 11V Input Range
LT3009 3µA IQ, 20mA Low Dropout Linear Regulator Low 3µA IQ, 1.6V to 20V Range, 20mA Output Current
LTC3388-1/
LTC3388-3
20V High Efficiency Nanopower Step-Down Regulator 860nA IQ in Sleep, 2.7V to 20V Input, VOUT: 1.2V to 5.0V, Enable and
Standby Pins
LTC3588-2 Nanopower Energy Harvesting Power Supply <1µA IQ in Regulation, UVLO Rising = 16V, UVLO Falling = 14V,
VOUT = 3.45V, 4.1V, 4.5V 5.0V
LT3652 Power Tracking 2A Battery Charger for Solar Power MPPT for Solar, 4.95V to 32V, Up to 2A Charge Current
LT3970 40V, 350mA Step-Down Regulator with 2.5µA IQIntegrated Boost and Catch Diodes, 4.2V to 40V Operating Range
LT3971 38V, 1.2A, 2MHz Step-Down Regulator with 2.8µA IQ4.3V to 38V Operating Range, Low Ripple Burst Mode
®
Operation
LT3991 55V, 1.2A 2MHz Step-Down Regulator with 2.8µA IQ4.3V to 55V Operating Range, Low Ripple Burst Mode Operation
LTC3631 45V, 100mA, Synchronous Step-Down Regulator with 12µA IQ4.5V to 45V Operating Range, Overvoltage Lockout Up to 60V
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LTC3330 Nanopower Buck-Boost DC/DC with Energy Harvesting Battery
Life Extender
VIN: 2.7V to 20V, BAT: 1.8V to 5.5V, 750nA IQ, 5mm × 5mm
QFN-32 Package
LTC3331 Nanopower Buck-Boost DC/DC with Energy Harvesting Battery
Charger
VIN: 2.7V to 20V, BAT: Up to 4.2V, Shunt Charger, Low Battery
Disconnect, 950nA IQ, 5mm × 5mm QFN-32 Package
Piezoelectric 3.3V Power Supply with LDO
Post Regulator for Reduced Output Ripple
35881 TA02a
PZ1
VIN
CAP
VIN2
D1
D0
PZ2
PGOOD
SW
VOUT
LTC3588-1
LT3009-3.3
GND
1µF
6V
4.7µF
6V
47µF
25V
COUT1
10µF
6V
COUT2
1µF
6V
10µH VOUT1
3.6V
SHDN
IN OUT
GND
VOUT2
3.3V
20mA
ADVANCED CERAMETRICS PFCB-W14
Peak-to-Peak Output Ripple vs COUT1
COUT1 (µF)
COUT2 = 1µF
VOUT RIPPLE PEAK-TO-PEAK (mV)
35881 TA02b
120
60
0
40
20
80
100
10 100
VOUT1 (LTC3588-1)
VOUT2 (LT3009-3.3)
