Pump. LTC3255MPDD Datasheet

LTC3255MPDD Datasheet PDF

Part LTC3255MPDD
Description Step-Down Charge Pump
Feature LTC3255MPDD; LTC3255 Wide VIN Range Fault Protected 50mA Step-Down Charge Pump FEATURES DESCRIPTION n Input V.
Manufacture Linear
Datasheet
Download LTC3255MPDD Datasheet




LTC3255MPDD
LTC3255
Wide VIN Range
Fault Protected 50mA
Step-Down Charge Pump
FEATURES
DESCRIPTION
n Input Voltage Range: 4V to 48V
n Adjustable Regulated Output: 2.4V to 12.5V
n Output Current: 50mA Maximum
n 16μA Quiescent Current in Regulation at No Load
n Input Fault Protection from –52V to 60V
n Multimode Charge Pump (2:1, 1:1) with Automatic
Mode Switching Maintains Regulation Over Wide
VIN Range
n Input Voltage Shunt Mode for Current-Fed Applications
n Power Good Output
n Overtemperature and Short-Circuit Protection
n Operating Junction Temperature: 150°C Maximum
n Thermally Enhanced 10-Lead MSOP and 10-Lead
(3mm × 3mm) DFN packages
APPLICATIONS
n Industrial Control, Factory Automation, Sensors, and
SCADA Systems
n Housekeeping Power Supplies
n Current-Boosting Voltage Regulators for 4mA to
20mA Current Loops
The LTC®3255 is a switched-capacitor step-down DC/DC
converter that produces a regulated output (2.4V to 12.5V
adjustable) from a 4V to 48V input. In applications where
the input voltage exceeds twice the output voltage, 2:1
capacitive charge pumping extends output current capabil-
ity beyond input supply current limits. At no load, Burst
Mode® operation cuts VIN quiescent current to 16µA.
With its integrated VIN shunt regulator, the LTC3255
excels in 4mA to 20mA current loop applications. The
device enables current multiplication; a 4mA input current
can power a 7.4mA load continuously. Alternatively, the
LTC3255 serves as a higher efficiency replacement for
linear regulators and provides a space-saving inductor-
free alternative to buck DC/DC converters.
The LTC3255 withstands reverse-polarity input supplies
and output short-circuits without damage. Safety features
including current limit and overtemperature protection
further enhance robustness. The LTC3255 is available in
thermally enhanced 10-lead MSOP and low profile 3mm
× 3mm 10-lead DFN packages.
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
TYPICAL APPLICATION
7.4mA DC Supply from 4mA to 20mA Current Loop
1µF
+
4mA TO 20mA INPUT
>10V COMPLIANCE
VIN C+
CVOUT
EN LTC3255
1µF
SHUNT
PGOOD
BIAS GND
FB
0.1µF
220k
PGOOD
2.15M
OUTPUT
3.3V
7.4mA
10µF
1.21M
3255 TA01a
For more information www.linear.com/LTC3255
Available Output Current
vs Input Current
40
37
34
31
28
25
22
AVAILABLE
IOUT
INCREASED
IOUT CAPABILITY
19
16
13
10
INPUT
CURRENT
7
4
4 6 8 10 12 14 16 18 20
INPUT CURRENT (mA)
3255 TA01b
3255f
1



LTC3255MPDD
LTC3255
ABSOLUTE MAXIMUM RATINGS (Notes 1, 2)
VIN, EN......................................................... –52V to 60V
VOUT........................................................................... 15V
VOUT Short-Circuit Duration (Note 6)................ Indefinite
IVOUT When VOUT < 0V (Note 4)..............................50mA
FB ..............................................................................±6V
PGOOD....................................................................... 15V
IPGOOD When VPGOOD < 0V (Note 5)......................100µA
Operating Junction Temperature
Range (Notes 3, 6).................................. –55°C to 150°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
MSE Only........................................................... 300°C
PIN CONFIGURATION
C+ 1
VOUT 2
FB 3
SHUNT 4
PGOOD 5
TOP VIEW
10 VIN
9 C
11
GND
8 GND
7 BIAS
6 EN
DD PACKAGE
10-LEAD (3mm × 3mm) PLASTIC DFN
TJMAX = 150°C, θJA = 43°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
C+ 1
VOUT 2
FB 3
SHUNT 4
PGOOD 5
TOP VIEW
11
GND
10
9
VCI–N
8 GND
7 BIAS
6 EN
MSE PACKAGE
10-LEAD PLASTIC MSOP
TJMAX = 150°C, θJA = 40°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC3255EDD#PBF
LTC3255EDD#TRPBF LGHD
10-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LTC3255IDD#PBF
LTC3255IDD#TRPBF
LGHD
10-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LTC3255HDD#PBF
LTC3255HDD#TRPBF LGHD
10-Lead (3mm × 3mm) Plastic DFN
–40°C to 150°C
LTC3255MPDD#PBF
LTC3255MPDD#TRPBF LGHD
10-Lead (3mm × 3mm) Plastic DFN
–55°C to 150°C
LTC3255EMSE#PBF
LTC3255EMSE#TRPBF LTGHF
10-Lead Plastic MSOP
–40°C to 125°C
LTC3255IMSE#PBF
LTC3255IMSE#TRPBF LTGHF
10-Lead Plastic MSOP
–40°C to 125°C
LTC3255HMSE#PBF
LTC3255HMSE#TRPBF LTGHF
10-Lead Plastic MSOP
–40°C to 150°C
LTC3255MPMSE#PBF
LTC3255MPMSE#TRPBF LTGHF
10-Lead Plastic MSOP
–55°C to 150°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on nonstandard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
3255f
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For more information www.linear.com/LTC3255



LTC3255MPDD
LTC3255
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at TA = 25°C. VIN = 12V unless otherwise noted. (Notes 2, 3)
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX
UNITS
VIN
VOUT
VUVLO_BK
Input Voltage Range (Note 7)
Output Voltage Range
VIN Undervoltage Lockout Threshold
with Shunt Disabled
VIN Rising, SHUNT = GND
Hysteresis, SHUNT = GND
l4
48
V
l 2.4
12.5
V
2.4
2.7
V
50
mV
VUVLO_SH
VIN Undervoltage Lockout Threshold
with Shunt Enabled
VIN Rising, SHUNT= BIAS
Hysteresis, SHUNT= BIAS
5
5.7
V
200
mV
IVIN
VIN Quiescent Current
EN Low
EN High, SHUNT = GND
EN High, SHUNT = BIAS
Shutdown
Enabled, Output in Regulation
Enabled, Output in Regulation
3
6
µA
16
35
µA
30
45
µA
IVOUT
Available Output Current
Shunt Disabled
SHUNT = GND
l 50
mA
Shunt Enabled
SHUNT = BIAS, IVIN = 4mA, VOUT = 3.3V
l 7.4
7.8
mA
VFB
Regulated Feedback Voltage
l 1.176 1.200 1.224
V
IFB
FB Pin Leakage
VFB = 1.3V
±10
nA
VEN_VIH
EN High Level Input Voltage
l 1.4
V
VEN_VIL
EN Low Level Input Voltage
l
0.4
V
IEN
EN Pin Input Current
VEN = 12V
VEN = 0V
0
±1
µA
0
±1
µA
ILIM
VOUT Current Limit
120
mA
fOSC
Oscillator Frequency
500
kHz
VPGTHRESH
PGOOD Rising Threshold
% of Final Regulation Voltage
l 90
94
98
%
VPG(LOW)
PGOOD Output Low Voltage
IPGOOD = 200µA
0.1
0.4
V
PGOOD High Impedance Leakage
VPGOOD = 12V
l
1
µA
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: All voltages are referenced to GND unless otherwise specified.
Note 3: The LTC3255E is guaranteed to meet performance specifications
from 0°C to 85°C operating 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 LTC3255I is guaranteed over the –40°C to 125°C operating junction
temperature range. The LTC3255H is guaranteed over the –40°C to 150°C
operating junction temperature range. The LTC3255MP is guaranteed over
the –55°C to 150°C operating junction temperature range. High junction
temperatures degrade operating lifetimes; operating lifetime is derated
for junction temperatures greater than 125°C. 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 resistance and other environmental factors.
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: The LTC3255 has an internal diode that conducts whenever VOUT
is pulled below GND. When so pulled, absolute maximum current out of
VOUT is 50mA.
Note 5: The LTC3255 has an internal diode that conducts whenever
PGOOD is pulled below GND. When so pulled, absolute maximum current
out of PGOOD is 100µA.
Note 6: This IC has overtemperature protection that is intended to protect
the device during momentary overload conditions. Junction temperatures
will exceed 150°C when overtemperature protection is active. Continuous
operation above the specified maximum operating junction temperature
may impair device reliability.
Note 7: This IC has input overvoltage protection that shuts down the
device whenever VIN exceeds the specified input voltage range. Shutdown
typically occurs when VIN exceeds 52V. VIN subsequently must fall below
50V (typical) for the IC to re-enable.
3255f
For more information www.linear.com/LTC3255
3







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