LTC3769_15 Datasheet, PDF (1/32 Pages) Linear Technology – 60V Low IQ Synchronous Boost Controller

Features
n _{Synchronous Operation for Highest Efficiency and}
Reduced Heat Dissipation
n _{Wide VIN Range: 4.5V to 60V (65V Abs Max);}
Operates Down to 2.3V After Start-Up
n _{Output Voltage Up to 60V}
n _{±1% 1.200V Reference Voltage}
n _{RSENSE or Inductor DCR Current Sensing}
n _{100% Duty Cycle Capability for Synchronous MOSFET}
n _{Low Quiescent Current: 28μA}
n _{Phase-Lockable Frequency (75kHz to 850kHz)}
n _{Programmable Fixed Frequency (50kHz to 900kHz)}
n _{Power Good Output Voltage Monitor}
n _{Low Shutdown Current: 4µA}
n _{Internal LDO Powers Gate Drive from VBIAS or EXTVCC}
n _{Thermally Enhanced Low Profile 24-Pin 4mm × 4mm}
QFN Package and 20-Lead TSSOP Package
Applications
n _Industrial
n _Automotive
n _Medical
n _Military
LTC3769
60V Low I_Q Synchronous
Boost Controller
Description
The LTC^®3769 is a high performance single output syn-
chronous boost converter controller that drives an all
N-channel power MOSFET stage. Synchronous rectifica-
tion increases efficiency, reduces power losses and eases
thermal requirements, simplifying high power boost ap-
plications. The 28µA no-load quiescent current extends
operating run time in battery-powered systems.
A 4.5V to 60V input supply range encompasses a wide
range of system architectures and battery chemistries.
When biased from the output of the boost converter or
another auxiliary supply, the LTC3769 can operate from an
input supply as low as 2.3V after start-up. The operating
frequency can be set within a 50kHz to 900kHz range or
synchronized to an external clock using the internal PLL.
The SS pin ramps the output voltage during start-up. The
PLLIN/MODE pin selects Burst Mode^® operation, pulse-
skipping mode or forced continuous mode at light loads.
L, LT, LTC, LTM, Burst Mode, OPTI-LOOP, Linear Technology and the Linear logo are registered
trademarks of Linear Technology Corporation. All other trademarks are the property of their
respective owners. Protected by U. S. Patents, including 5408150, 5481178, 5705919,
5929620, 6177787, 6498466, 6580258, 6611131.
Typical Application
120W, 12V to 24V/5A Synchronous Boost Converter
V_IN
4.5V TO 60V
DOWN TO 2.3V
AFTER START-UP IF
VBIAS IS POWERED
FROM V_OUT
22µF
10nF
15nF ^8.66K
100pF
4mΩ
3.3µH
VBIAS
RUN
SENSE⁺
SS
SENSE^–
LTC3769 BG
ITH
PLLIN/MODE
FREQ
OVMODE
TG
SW
BOOST
ILIM
INTV_CC
PGOOD
GND
VFB
EXTV_CC
3769 TA01a
0.1µF
4.7µF
220µF
V_OUT
24V/5A
V_OUT FOLLOWS V_IN FOR V_IN > 24V
232k
12.1k
For more information www.linear.com/LTC3769
Efficiency and Power Loss
vs Output Current
100
10
90
EFFICIENCY
1
80
70
POWER
0.1
LOSS
60
0.01
50
40
0.0001
0.001
0.001 0.01 0.1
1
10
OUTPUT CURRENT (A)
3769 TA01b
3769f
1