LTC3606B Datasheet, PDF (1/20 Pages) Linear Technology – 800mA Synchronous Step-Down DC/DC with Average Input Current Limit

LTC3606B
800mA Synchronous
Step-Down DC/DC with
Average Input Current Limit
FEATURES
DESCRIPTION
n _{Programmable Average Input Current Limit:}
±5% Accuracy
n _{Step-Down Output: Up to 96% Efficiency}
n _{Low Noise Pulse-Skipping Operation at Light Loads}
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}
n _{Low Dropout Operation: 100% Duty Cycle}
n _{Internal Soft-Start}
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 8-Lead}
3mm × 3mm DFN Package
APPLICATIONS
n _{High Peak Load Current Applications}
n _{USB Powered Devices}
n _{Supercapacitor Charging}
n _{Radio Transmitters and Other Handheld Devices}
The LTC^®3606B is an 800mA 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, extending
the run time in battery-operated systems. Low output
voltages are supported with the 0.6V feedback reference
voltage. The LTC3606B can supply 800mA output current.
The LTC3606B’s programmable average input current
limit is ideal for USB applications and for point-of-load
power supplies because the LTC3606B’s limited input
current will still allow its output to deliver high peak load
currents without collapsing the input supply. 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 LTC3606B is available
in an 8-Lead 3mm × 3mm DFN package.
L, LT, LTC, LTM, 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.
TYPICAL APPLICATION
Monolithic Buck Regulator with Input Current Limit
V_IN 3.4V
TO 5.5V
PGOOD
C_IN
10μF
499k
V_IN
SW
LTC3606B
RUN
PGOOD
RLIM
V_FB
GND
1000pF ^116k
I_LIM = 475mA
1.5μH
1210k
255k
V_OUT
3.4V AT
800mA
+ 2.2mF
s2
SuperCap
3606B TA01
GSM Pulse Load
V_OUT
200mV/DIV
V_IN
AC-COUPLED
1V/DIV
I_OUT
500mA/DIV
I_IN
500mA/DIV
1ms/DIV
V_IN = 5V, 500mA COMPLIANT
I_LOAD = 0A to 2.2A
3606B TA01b
3606bfa
1