POWER LOSS (W)
LTC3409A
600mA Low V Buck
IN
Regulator in 3mm 3mm DFN
FEATURES DESCRIPTION
n
1.6V to 5.5V Input Voltage Range The LTC 3409A is a high ef ciency, monolithic synchronous
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0.62V to 5.5V Output Voltage Range buck regulator using a constant frequency, current mode
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Internal Soft-Start architecture. The LTC3409A improves upon the LTC3409s
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Selectable 1.7MHz or 2.6MHz Constant Frequency light load regulation in Burst Mode operation. The output
Operation voltage is adjusted via an external resistor divider.
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Internal Oscillator Can Be Synchronized to an
Fixed switching frequencies of 1.7MHz and 2.6MHz are
External Clock, 1MHz to 3MHz Range
supported. Alternatively, an internal PLL will synchronize
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High Ef ciency: Up to 95%
to an external clock in the frequency range of 1MHz to
n
65A Quiescent Current, Burst Mode Operation
3MHz. This range of switching frequencies allows the
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600mA Output Current (V = 1.8V, V = 1.2V)
IN OUT
use of small surface mount inductors and capacitors,
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750mA Peak Inductor Current
including ceramics.
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No Schottky Diode Required
n Supply current during Burst Mode operation is only
Low Dropout Operation: 100% Duty Cycle
n 65A dropping to <1A in shutdown. The 1.6V to 5.5V
0.612V Reference Voltage
n input voltage range makes the LTC3409A ideally suited
Stable with Ceramic Capacitors
n for single cell Li-Ion, Li-Metal and 2-cell alkaline, NiCd
Shutdown Mode Draws <1A Supply Current
n or NiMH battery-powered applications. 100% duty cycle
Current Mode Operation for Excellent Line and Load
capability provides low dropout operation, extending bat-
Transient Response
n tery life in portable systems. Burst Mode operation can be
Overtemperature Protection
n user-enabled, increasing ef ciency at light loads, further
Available in a Low Pro le (0.75mm)
extending battery life.
8-Lead (3mm 3mm) DFN Package
The internal synchronous switch increases ef ciency and
eliminates the need for an external Schottky diode. Internal
APPLICATIONS
soft-start offers controlled output voltage rise time at start-
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Cellular Phones
up without the need for external components.
n
Digital Cameras
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
n
MP3 Players
Technology Corporation. All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131.
TYPICAL APPLICATION
Burst Mode Ef ciency, 1.8V
OUT
High Ef ciency Step-Down Converter 100 1
2.5V , BURST
IN
90
LTC3409A 2.2H* 80
V V 0.1
IN
OUT
V SW
IN
70
1.8V TO 5.5V 1.8V
10pF
4.7F
22F
RUN 3.6V , BURST
IN
60
267k
s 2
MODE V
FB
50 0.01
4.2V , BURST
137k IN
SYNC GND
40
POWER LOST
30 3.6V , BURST
IN
*SUMIDA CDRH2D18/LD 0.001
3409A TA01
20
10
0 0.0001
0 1 10 100 1000
LOAD CURRENT (mA)
3409A TA01b
3409af
1
EFFICIENCY (%)LTC3409A
ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION
(Note 1)
TOP VIEW
Input Supply Voltage ................................... 0.3V to 6V
RUN, V , MODE, SYNC Voltages . 0.3V to (V + 0.3V)
FB IN
V 1 8 SYNC
FB
SW Voltage ................................... 0.3V to (V + 0.3V)
IN GND 2 7 RUN
9
Operating Temperature Range (Note 2) ..40C to 85C
V 3 6 SW
IN
V 4 5 MODE
Junction Temperature (Note 3) ........................... 125C
IN
Storage Temperature Range .................. 65C to 125C
DD PACKAGE
8-LEAD (3mm 3mms ) PLASTIC DFN
T = 125C, = 43C/W
JMAX JA
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3409AEDD#PBF LTC3409AEDD#TRPBF LFGY 8-Lead (3mm 3mm) Plastic DFN 40C to 85C
LTC3409AIDD#PBF LTC3409AIDD#TRPBF LFGY 40C to 85C
8-Lead (3mm 3mm) Plastic DFN
Consult LTC Marketing for parts speci ed with wider operating temperature ranges. *Temperature grades are identi ed by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based nish parts.
For more information on lead free part marking, go to: