LT3436 Datasheet, PDF (1/16 Pages) Linear Technology – 3A, 800kHz Step-Up Switching Regulator

LT3436
3A, 800kHz Step-Up
Switching Regulator
FEATURES
■ _{Constant 800kHz Switching Frequency}
■ _{Wide Operating Voltage Range: 3V to 25V}
■ _{High Efficiency 0.1Ω/3A Switch}
■ _{1.2V Feedback Reference Voltage}
■ _{±2% Overall Output Voltage Tolerance}
■ _{Uses Low Profile Surface Mount External}
Components
■ _{Low Shutdown Current: 11µA}
■ _{Synchronizable from 1MHz to 1.4MHz}
■ _{Current-Mode Control}
■ _{Constant Maximum Switch Current Rating}
at All Duty Cycles*
■ _{Available in a Small Thermally Enhanced}
TSSOP-16 Package
U
APPLICATIO S
■ _{DSL Modems}
■ _{Portable Computers}
■ _{Battery-Powered Systems}
■ _{Distributed Power}
DESCRIPTIO
The LT^®3436 is an 800kHz monolithic boost switching
regulator. A high efficiency 3A, 0.1Ω switch is included on
the die together with all the control circuitry required to
complete a high frequency, current-mode switching regu-
lator. Current-mode control provides fast transient re-
sponse and excellent loop stability.
New design techniques achieve high efficiency at high
switching frequencies over a wide operating range. A low
dropout internal regulator maintains consistent perfor-
mance over a wide range of inputs from 24V systems to Li-
Ion batteries. An operating supply current of 1mA main-
tains high efficiency, especially at lower output currents.
Shutdown reduces quiescent current to 11µA. Maximum
switch current remains constant at all duty cycles. Syn-
chronization capability allows an external logic level signal
to increase the internal oscillator from 1MHz to 1.4MHz.
Full cycle-by-cycle switch current limit protection and ther-
mal shutdown are provided. High frequency operation al-
lows the reduction of input and output filtering components
and permits the use of tiny chip inductors. The LT3436 is
available in an exposed pad, 16-pin TSSOP package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
*Protectd by U.S. Patents including 6535042, 6611131, 6498466
TYPICAL APPLICATIO
5V to 12V Boost Converter
3.9µH
INPUT
5V
4.7µF
CERAMIC
OPEN
OR
HIGH
= ON
V_IN
V_SW
LT3436
SHDN
FB
SYNC GND ^VC
10nF
4.7k
B220A
90.9k
10k
470pF ^1%
†_{MAXIMUM OUTPUT CURRENT IS SUBJECT TO THERMAL DERATING.}
OUTPUT
12V
0.9A^†
22µF
CERAMIC
3436 TA01
Efficiency vs Load Current
90 _{VIN = 5V}
V_OUT = 12V
85
80
75
70
65
60
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
LOAD CURRENT (A)
3436 TA01b
3436fa
1