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LTC3619IDD#PBF

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P22
LTC3619
1
3619fa
Typical applicaTion
DescripTion
400mA/800mA Synchronous
Step-Down DC/DC with
Average Input Current Limit
The LT C
®
3619 is a dual monolithic synchronous buck
regulator using a constant frequency, current mode
architecture.
The input supply voltage range is 2.5V to 5.5V, making it
ideal for Li-Ion and USB powered applications. 100% duty
cycle capability provides low dropout operation, extend-
ing the run time in battery-operated systems. Low output
voltages are supported with the 0.6V feedback reference
voltage. Channel 1 and channel 2 can supply 400mA and
800mA output current, respectively.
The LTC3619’s programmable average input current limit
is ideal for USB applications and for point-of-load power
supplies because the LTC3619’s limited input current will
still allow its output to deliver high peak load currents
without collapsing the input supply. When the sum of both
channels’ currents exceeds the input current limit, channel 2
is current limited while channel 1 remains regulated. The
operating frequency is internally set at 2.25MHz allowing
the use of small surface mount inductors. Internal soft-start
reduces in-rush current during start-up. The LTC3619 is
available in small MSOP and 3mm × 3mm DFN packages
and is also available in a
low noise
, high efficiency pulse-
skipping version, LTC3619B.
Dual Monolithic Buck Regulator in 10-Lead 3mm × 3mm DFN
L, LT , LT C , LT M , Linear Technology, the Linear logo and Burst Mode are registered trademarks
and Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners. Protected by U.S.Patents, including 5481178, 6127815,
6304066, 6498466, 6580258, 6611131.
FeaTures
applicaTions
n
Programmable Average Input Current Limit:
±5% Accuracy
n
Dual Step-Down Outputs: Up to 96% Efficiency
n
Low Ripple (<25mV
P-P
) Burst Mode
®
Operation:
I
Q
= 50µA
n
Input Voltage Range: 2.5V to 5.5V
n
Output Voltage Range: 0.6V to 5V
n
2.25MHz Constant-Frequency Operation
n
Power Good Output Voltage Monitor for Each Channel
n
Low Dropout Operation: 100% Duty Cycle
n
Independent Internal Soft-Start for Each Channel
n
Current Mode Operation for Excellent Line and Load
Transient Response
n
±2% Output Voltage Accuracy
n
Short-Circuit Protected
n
Shutdown Current ≤ 1μA
n
Available in Small Thermally Enhanced 10-Lead MSE
and 3mm × 3mm DFN Packages
n
High Peak Load Current Applications
n
USB Powered Devices
n
Supercapacitor Charging
n
Radio Transmitters and Other Handheld Devices
GSM Pulse Load
1ms/DIV
V
OUT2
200mV/DIV
I
IN
500mA/DIV
I
OUT
500mA/DIV
V
IN
1V/DIV
AC-COUPLED
3619 TA01b
V
IN
= 5V, 500mA COMPLIANT,
I
LOAD
= 0A TO 2.2A, CHANNEL 1 UNLOADED
V
IN
RUN2 RUN1
LTC3619
V
FB2
SW2
SW1
PGOOD1PGOOD2
V
FB1
22pF
RLIM GND
V
IN
3.4V TO 5.5V
V
OUT2
3.4V AT
800mA
V
OUT1
1.8V AT
400mA
3619 TA01a
1190k
511k
255k
255k
1.5µH 3.3µH
2.2mF
×2
SuperCap
10µF
10µF
+
1000pF 116k
I
LIM
= 475mA
LTC3619
2
3619fa
absoluTe MaxiMuM raTings
Input Supply Voltage (V
IN
) ............................. –0.3 to 6V
V
FB1
, V
FB2
........................................ –0.3V to V
IN
+ 0.3V
RUN1, RUN2, RLIM .......................... –0.3V to V
IN
+ 0.3V
SW1, SW2 ........................................ –0.3V to V
IN
+ 0.3V
PGOOD1, PGOOD2 ........................... –0.3V to V
IN
+ 0.3V
P-Channel SW Source Current (DC) (Note 2)
Channel 1 ........................................................ 600mA
Channel 2 ................................................................1A
N-Channel SW Source Current (DC) (Note 2)
Channel 1 ........................................................ 600mA
Channel 2 ................................................................1A
(Note 1)
TOP VIEW
DD PACKAGE
10-LEAD (3mm × 3mm) PLASTIC DFN
10
9
6
7
8
4
5
3
2
1
V
FB2
RUN2
PGOOD2
SW2
V
IN
V
FB1
RUN1
RLIM
PGOOD1
SW1
11
T
JMAX
= 125°C, θ
JA
= 40°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
1
2
3
4
5
V
FB1
RUN1
RLIM
PGOOD1
SW1
10
9
8
7
6
V
FB2
RUN2
PGOOD2
SW2
V
IN
TOP VIEW
MSE PACKAGE
10-LEAD PLASTIC MSOP
11
T
JMAX
= 125°C, θ
JA
= 45°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
pin conFiguraTion
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
V
IN
Operating Voltage Range
l
2.5 5.5 V
V
UV
V
IN
Undervoltage Lockout V
IN
Low to High
l
2.1 2.5 V
orDer inForMaTion
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3619EDD#PBF LTC3619EDD#TRPBF LFKM
10-Lead (3mm × 3mm) Plastic DFN
–40°C to 85°C
LTC3619IDD#PBF LTC3619IDD#TRPBF LFKM
10-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LTC3619EMSE#PBF LTC3619EMSE#TRPBF LTFKN 10-Lead Plastic MSOP –40°C to 85°C
LTC3619IMSE#PBF LTC3619IMSE#TRPBF LTFKN 10-Lead Plastic MSOP –40°C to 125°C
Consult LT C 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/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
Peak SW Source and Sink Current (Note 2)
Channel 1 ........................................................ 900mA
Channel 2 ................................................................ 2A
Operating Junction Temperature Range
(Notes 3, 6, 8) .................................... –40°C to 125°C
Storage Temperature Range .................. –65°C to 125°C
Lead Temperature (Soldering, 10 sec)
MSOP Package .................................................300°C
Reflow Peak Body Temperature ............................ 260°C
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C, V
IN
= 5V, unless otherwise noted. (Note 3)
LTC3619
3
3619fa
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: Guaranteed by long term current density limitations.
Note 3: The LTC3619 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3619E is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 85°C operating
junction temperature range are assured by design, characterization and
correlation with statistical process controls. The LTC3619I is guaranteed
to meet specified performance over the full –40°C to 125°C operating
junction temperature range.
Note 4: Dynamic supply current is higher due to the internal gate charge
being delivered at the switching frequency.
The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C, V
IN
= 5V, unless otherwise noted. (Note 3)
Note 5: The switch on-resistance is guaranteed by correlation to wafer
level measurements.
Note 6: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation
above the specified maximum operating junction
temperature may impair device reliability.
Note 7:
The converter is tested in a proprietary test mode that connects
the output of the error amplifier to the SW pin, which is connected to an
external servo loop.
Note 8: T
J
is calculated from the ambient temperature T
A
and the power
dissipation as follows: T
J
= T
A
+ (P
D
)(θ
JA
°C/W).
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
FB
Feedback Pin Input Current
l
±30 nA
V
FBREG
Feedback Voltage (Channels 1, 2) LTC3619E, –40°C ≤ T
J
≤ 85°C
LTC3619I, –40°C ≤ T
J
≤ 125°C
l
l
0.588
0.582
0.600
0.600
0.612
0.618
V
V
ΔV
LINEREG
V
FB
Line Regulation V
IN
= 2.5V to 5.5V (Note 7) 0.01 0.25 %/V
ΔV
LOADREG
V
FB
Load Regulation (Channel 1)
V
FB
Load Regulation (Channel 2)
I
LOAD
= 0mA to 400mA (Note 7)
I
LOAD
= 0mA to 800mA (Note 7)
0.5
0.5
%
%
I
S
Supply Current
Active Mode (Note 4)
Sleep Mode
Shutdown
V
FB1
= V
FB2
= 0.95 × V
FBREG
V
FB
= 1.05 × V
FBREG
,
V
IN
= 5.5V
V
RUN1
= V
RUN2
= 0V, V
IN
= 5.5V
600
50
875
100
1
µA
µA
µA
f
OSC
Oscillator Frequency V
FB
= 0.6V
l
1.8 2.25 2.7 MHz
I
LIM(PEAK)
Peak Switch Current Limit
Channel 1 (400mA)
Channel 2 (800mA)
V
IN
= 5V, V
FB
< V
FBREG
, Duty Cycle <35%
550
1200
800
1600
mA
mA
I
INLIM (PEAK)
Input Average Current Limit RLIM = 116k
RLIM = 116k, LTC3619E
RLIM = 116k, LTC3619I
l
l
450
437
427
475
475
475
500
513
523
mA
mA
mA
R
DS(ON)
Channel 1 (Note 5)
Top Switch On-Resistance
Bottom Switch On-Resistance
Channel 2 (Note 5)
Top Switch On-Resistance
Bottom Switch On-Resistance
V
IN
= 5V, I
SW
= 100mA
V
IN
= 5V, I
SW
= 100mA
V
IN
= 5V, I
SW
= 100mA
V
IN
= 5V, I
SW
= 100mA
0.45
0.35
0.27
0.25
Ω
Ω
Ω
Ω
I
SW(LKG)
Switch Leakage Current V
IN
= 5V, V
RUN
= 0V 0.01 1 µA
t
SOFTSTART
Soft-Start Time V
FB
from 0.06V to 0.54V 0.3 0.95 1.3 ms
V
RUN
RUN Threshold High
l
0.4 1 1.2 V
I
RUN
RUN Leakage Current
l
0.01 1 µA
PGOOD Power Good Threshold Entering Window
V
FB
Ramping Up
V
FB
Ramping Down
Leaving Window
V
FB
Ramping Up
V
FB
Ramping Down
–5
5
–7
7
9
–9
11
–11
%
%
%
%
PGOOD Blanking Power Good Blanking Time PGOOD Rising and Falling, V
IN
= 5V 90 µs
R
PGOOD
Power Good Pull-Down On-Resistance 8 15 30 Ω
I
PGOOD
PGOOD Leakage Current V
PGOOD
= 5V ±1 µA
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LTC3619IDD#PBF

Mfr. #:
Buy LTC3619IDD#PBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators 400mA/800mA Synchronous Step-Down DC/DC Converter with Average Input Current Limit
Lifecycle:
New from this manufacturer.
Delivery:
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