LTC1266-33 Datasheet, PDF (1/20 Pages) Linear Technology – Synchronous Regulator Controller for N- or P-Channel MOSFETs

LTC1266
LTC1266-3.3/LTC1266-5
Synchronous Regulator
Controller for
N- or P-Channel MOSFETs
FEATURES
DESCRIPTIO
s _{Ultra-High Efficiency: Over 95% Possible}
The LTC^®1266 series is a family of synchronous switching
s _{Drives N-Channel MOSFET for High Current or}
regulator controllers featuring automatic Burst Mode^TM
P-Channel MOSFET for Low Dropout
operation to maintain high efficiencies at low output
s _{Pin Selectable Burst Mode Operation}
currents. These devices drive external power MOSFETs at
s _{1% Output Accuracy (LTC1266A)}
switching frequencies up to 400kHz using a constant off-
s _{Pin Selectable Phase of Topside Driver for Boost}
time current mode architecture providing constant ripple
or Step-Down Operation
current in the inductor. They can drive either an N-channel
s _{Wide VIN Range: 3.5V to 20V}
or a P-channel topside MOSFET.
s _{On-Chip Low-Battery Detector}
The operating current level is user-programmable via an
s _{High Efficiency Maintained over Large Current Range external current sense resistor. Wide input supply range}
s _{Low 170µA Standby Current at Light Loads}
allows operation from 3.5V to 18V (20V maximum).
s _{Current Mode Operation for Excellent Line and Load Constant off-time architecture provides low dropout regu-}
Transient Response
s _{Logic Controlled Micropower Shutdown: IQ < 40µA}
lation limited only by the R_DS(ON) of the topside MOSFET
(when using the P-channel) and the resistance of the
s _{Short Circuit Protection}
inductor and current sense resistor.
s _{Synchronous Switching with Nonoverlaping Gate Drives}
s _{Available in 16-Pin Narrow SO Package}
The LTC1266 series combines synchronous switching for
APPLICATI S
maximum efficiency at high currents with an automatic
low current operating mode, called Burst Mode operation,
s _{Notebook and Palmtop Computers}
s _{Portable Instruments}
s _{Cellular Telephones}
which reduces switching losses. Standby power is re-
duced to only 1mW at V_IN = 5V (at I_OUT = 0). Load currents
in Burst Mode operation are typically 0mA to 500mA.
s _{DC Power Distribution Systems}
s _{GPS Systems}
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode is a trademark of Linear Technology Corporation.
TYPICAL APPLICATI
V_IN
4V TO 9V ₊
C_IN
100µF
×2
LOW BAT IN
0V = NORMAL
>1.5V = SHUTDOWN
R_C
470Ω
C_C
3300pF
C_T
180pF
V_IN
LB_IN
PWR V_IN
LB_OUT
PINV
TDRIVE
LTC1266-3.3
SHDN SENSE⁺
I_TH
C_T
BINH
SENSE ^–
BDRIVE
SGND PGND
D2
MBR0530T1
C_B
0.1µF
LOW BAT OUT
100k
N-CHANNEL
Si9410
1000pF
N-CHANNEL
Si9410
L*
R_SENSE
5µH _0.02Ω
V_OUT
3.3V
5A
+
D1
MBRS130LT3
C_OUT
330µF
×2
LTC1266 • TA01
*COILTRONICS CTXO212801
Figure 1. High Efficiency Step-Down Converter
LTC1266-3.3 Efficiency
100
V_IN = 5V
95
90
85
80
0.01
0.1
1
5
LOAD CURRENT (A)
LTC1266 • TA02
1