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LT3514IUFD#PBF

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P26
LT3514
1
3514fa
For more information www.linear.com/LT3514
TYPICAL APPLICATION
FEATURES
APPLICATIONS
DESCRIPTION
Triple Step-Down Switching
Regulator with 100%
Duty Cycle Operation
The LT
®
3514 consists of three buck regulators (2A, 1A,
1A output current). The device has a wide operating input
range of 3.2V to 36V. An on-chip boost regulator allows
each channel to operate up to 100% duty cycle. The LT3514
is designed to minimize external component count and
results in a simple and small application circuit.
The LT3514 operates robustly in fault conditions. Cycle-
by-cycle peak current limit and catch diode current limit
sensing protect the IC during overload conditions. Ther
-
mal shutdown protects the power switches at elevated
temperatures. Soft-start helps control the peak inductor
current during startup.
The LT3514 also features output voltage tracking and
sequencing, programmable frequency, programmable
undervoltage lockout, and a power good pin to indicate
when all outputs are in regulation.
The LT3514 has one fewer channel (CH2) than the LT3504,
and has one channel (CH3) that outputs 2A instead of 1A.
The LT3514 in QFN is pin compatible with the LT3504. The
LT3504 provides four 1A outputs.
L, LT, LTC, LTM, 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.
Triple Buck Regulator
LT3514 Start-Up and Shutdown
Waveform. V
IN
(Top Trace) Is Ramped
from OV Up to 8V and Then Back Down
to 0V. The Other Three Traces Are the
Output Voltages of All Three Channels
n
Wide Input Voltage Range: 3.2V to 36V
(40V Transient)
n
Three Outputs: 2A, 1A, 1A
n
100% Duty Cycle Operation
n
Resistor-Programmed Constant Frequency
n
Short-Circuit Robust
n
Wide SYNC Range: 350kHz to 2.2MHz
n
Anti-Phase Switching Reduces Ripple
n
Feedback Voltage: 800mV
n
Independent Run/Soft-Start Pins
n
Shutdown with UVLO
n
Internal Compensation
n
Thermal Shutdown
n
Tiny 28-Lead (4mm × 5mm) Thermally Enhanced
QFN Package
n
24-Lead Exposed Pad TSSOP
n
Automotive Battery Regulation
n
Industrial Control Supplies
n
Wall Transformer Regulation
n
Distributed Supply Regulation
3514 TA01a
8.2µH
1µF
PG
1µF
×2
10µH
V
IN
5.4V TO 20V
TRANSIENT TO 40V
47nF
18.2k
1MHz
GND
LT3514
SKY
SW5
V
IN
V
IN
EN/UVLO
PG
RUN/SS1
RUN/SS3
RUN/SS4
RT/SYNC
SW1
DA1
FB1
1.8V/1A
100pF
12.7k
10.2k
22µF
SW3
DA3
FB3
3.3V/2A
47pF
31.6k
10.2k
47µF
SW4
DA4
FB4
5V/1A
22pF
53.6k
10.2k
22µF
3.3µH
4.7µH
100ms/DIV
3514 TA01b
5V CHANNEL BEGINS
100% DC OPERATION
UVLO = ~2.9V
PARTS SHUTS
OFF
3.3V CHANNEL BEGINS
100% DC OPERATION
V
IN
1V/DIV
CH4 1V/DIV
CH3 1V/DIV
CH1 1V/DIV
LT3514
2
3514fa
For more information www.linear.com/LT3514
PIN CONFIGURATION
ABSOLUTE MAXIMUM RATINGS
EN/UVLO ................................................................... 40V
EN/UVLO Pin Above V
IN
.............................................. 5V
V
IN
............................................................................40V
SKY ........................................................................... 46V
SW5 ..........................................................................47V
RUN/SS .......................................................................6V
FB ...............................................................................6V
RT/SYNC .....................................................................6V
(Note 1)
9 10
TOP VIEW
UFD PACKAGE
28-LEAD (4mm × 5mm) PLASTIC QFN
29
GND
11 12 13
28 27 26 25 24
14
23
6
5
4
3
2
1
NC
NC
DA3
SW3
SW1
DA1
SW4
DA4
NC
FB3
FB1
FB4
GND
RT/SYNC
EN/UVLO
RUN/SS3
V
IN
GND
V
IN
SKY
SW5
PG
V
IN
GND
V
IN
RUN/SS4
RUN/SS1
NC
7
17
18
19
20
21
22
16
8
15
θ
JA
= 43°C/W
EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB
1
2
3
4
5
6
7
8
9
10
11
12
TOP VIEW
FE PACKAGE
24-LEAD PLASTIC TSSOP
24
23
22
21
20
19
18
17
16
15
14
13
V
IN
NC
DA3
SW3
SW3
SW1
DA1
SW4
DA4
NC
V
IN
V
IN
SKY
SW5
GND
PG
FB3
FB1
FB4
RT/SYNC
EN/UVLO
RUN/SS3
RUN/SS1
RUN/SS4
25
GND
θ
JA
= 33°C/W
EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LT3514EUFD#PBF LT3514EUFD#TRPBF 3514
28-Lead (4mm × 5mm) Plastic QFN
–40°C to 125°C
LT3514IUFD#PBF LT3514IUFD#TRPBF 3514
28-Lead (4mm × 5mm) Plastic QFN
–40°C to 125°C
LT3514EFE#PBF LT3514EFE#TRPBF LT3514FE 24-Lead Plastic TSSOP –40°C to 125°C
LT3514IFE#PBF LT3514IFE#TRPBF LT3514FE 24-Lead Plastic TSSOP –40°C to 125°C
LT3514HFE#PBF LT3514HFE#TRPBF LT3514FE 24-Lead Plastic TSSOP –40°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 non-standard 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/
PG .............................................................................25V
Operating Junction Temperature Range (Notes 2, 7)
LT3514EUFD ...................................... –40°C to 125°C
LT3514IUFD ....................................... –40°C to 125°C
LT3514EFE ......................................... –40°C to 125°C
LT3514IFE .......................................... –40°C to 125°C
LT3514HFE ......................................... –40°C to 150°C
Storage Temperature Range .................. –65°C to 150°C
LT3514
3
3514fa
For more information www.linear.com/LT3514
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V unless otherwise noted.
SYMBOL CONDITIONS MIN TYP MAX UNITS
EN/UVLO Threshold Voltage Rising
l
1.2 1.44 1.6 V
EN/UVLO Threshold Voltage Hysteresis 110 mV
EN/UVLO Threshold Current Hysteresis V
EN/UVLO
= Measured Rising Threshold – 50mV
(Note 3)
1.3 µA
Internal V
IN
Undervoltage Lockout 2.4 2.9 3.2 V
Quiescent Current (V
IN
) in Shutdown V
EN/UVLO
= 0V 0.01 2 µA
Quiescent Current (V
IN
) V
EN/UVLO
= 1V 4 10 µA
Quiescent Current (V
IN
) V
EN/UVLO
= 1.5V, V
RUN/SS(1,3,4)
= Open,
V
FB(1,3,4)
= 0.9V, V
SKY
= 17V (Note 4)
2.7 mA
Quiescent Current (SKY) V
EN/UVLO
= 1.5V, V
RUN/SS(1,3,4)
= Open,
V
FB(1,3,4)
= 0.9V, V
SKY
= 17V (Note 4)
4.4 mA
RUN/SS Pin Source Current V
RUN/SS
= 0V 1.3 µA
RUN/SS Pin Threshold for Switching V
FB
= 0V 50 100 mV
Feedback Voltage
l
790
784
800
800
810
816
mV
mV
FB Pin Current V
FB
= Measured V
FB
(Note 5)
l
15 150 nA
Reference Line Regulation V
IN
= 5V to 40V –0.015 %/V
SKY Pin Current I
SW1
= 1A or I
SW4
= 1A 27 40 mA
SKY Pin Current I
SW3
= 2A 54 80 mA
SKY Voltage above V
IN
Voltage V
SKY
– V
IN
4.85 V
Switching Frequency R
T
= 6.34k
R
T
= 18.2k
R
T
= 100k
l
l
l
1.8
0.85
220
2.1
1
270
2.4
1.15
320
MHz
MHz
kHz
Switching Phase R
T
= 18.2k 150 180 210 Deg
SYNC Threshold Voltage 1.25 V
SYNC Input Frequency 0.35 2.2 MHz
Switch Current Limit (SW1,4) (Note 6) 1.45 1.75 2.1 A
Switch V
CESAT
(SW1,4) I
SW1, SW4
= 1A 400 mV
Switch Leakage Current (SW1,4) 0.1 2 µA
Catch Diode Current Limit (SW1,4) FB = 0V
FB = 0.7V
0.75
1.0
1.15
1.45
1.33
1.67
A
A
Switch Current Limit (SW3) (Note 6) 3 3.5 4.2 A
Switch V
CESAT
(SW3) I
SW3
= 2A 400 mV
Switch Leakage Current (SW3) 0.1 4 µA
Catch Diode Current Limit (SW3) FB = 0V
FB = 0.7V
1.5
2.0
2
2.5
2.4
3.0
A
A
Switch Current Limit (SW5) (Note 6) 220 320 mA
Switch V
CESAT
(SW5) I
SW
= 200mA 230 mV
Switch Leakage Current (SW5) 0.1 2 µA
Boost Diode Current Limit (SW5) V
IN
= 5V 350 450 mA
PG Threshold Offset V
FB
Rising 65 90 125 mV
PG Hysteresis V
FB
Rising – V
FB
Falling 35 mV
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LT3514IUFD#PBF

Mfr. #:
Buy LT3514IUFD#PBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators Triple Step-Down Switching Regulator with 100% Duty Cycle Operation
Lifecycle:
New from this manufacturer.
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