LTC1624_15 Datasheet, PDF (1/28 Pages) Linear Technology – High Efficiency SO-8 N-Channel Switching Regulator Controller

FEATURES
s _{N-Channel MOSFET Drive}
s _{Implements Boost, Step-Down, SEPIC}
and Inverting Regulators
s _{Wide VIN Range: 3.5V to 36V Operation}
s _{Wide VOUT Range: 1.19V to 30V in Step-Down}
Configuration
s _{±1% 1.19V Reference}
s _{Low Dropout Operation: 95% Duty Cycle}
s _{200kHz Fixed Frequency}
s _{Low Standby Current}
s _{Very High Efficiency}
s _{Remote Output Voltage Sense}
s _{Logic-Controlled Micropower Shutdown}
s _{Internal Diode for Bootstrapped Gate Drive}
s _{Current Mode Operation for Excellent Line and}
Load Transient Response
s _{Available in an 8-Lead SO Package}
U
APPLICATIONS
s _{Notebook and Palmtop Computers, PDAs}
s _{Cellular Telephones and Wireless Modems}
s _{Battery-Operated Digital Devices}
s _{DC Power Distribution Systems}
s _{Battery Chargers}
LTC1624
High Efficiency SO-8
N-Channel Switching
Regulator Controller
DESCRIPTION
The LTC^®1624 is a current mode switching regulator
controller that drives an external N-channel power MOSFET
using a fixed frequency architecture. It can be operated in
all standard switching configurations including boost,
step-down, inverting and SEPIC. Burst Mode^TM operation
provides high efficiency at low load currents. A maximum
high duty cycle limit of 95% provides low dropout operation
which extends operating time in battery-operated systems.
The operating frequency is internally set to 200kHz, allowing
small inductor values and minimizing PC board space. The
operating current level is user-programmable via an external
current sense resistor. Wide input supply range allows
operation from 3.5V to 36V (absolute maximum).
A multifunction pin (I_TH/RUN) allows external
compensation for optimum load step response plus
shutdown. Soft start can also be implemented with the
I_TH/RUN pin to properly sequence supplies.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode is a trademark of Linear Technology Corporation.
TYPICAL APPLICATION
C_C
470pF
R_C
6.8k
SENSE^–
V_IN
I_TH/RUN BOOST
LTC1624
V_FB
TG
100pF
GND
SW
V_IN
4.8V TO 28V
1000pF
M1
Si4412DY
R_SENSE
0.05Ω
+ ^CIN
22µF
35V
×2
C_B
0.1µF
D1
MBRS340T3
L1
10µH
V_OUT
3.3V
2A
R2
35.7k
+ ^COUT
100µF
R1
10V
20k
×2
Figure 1. High Efficiency Step-Down Converter
1624 F01
1