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.
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Synchronous Operation for Highest Efficiency and
Reduced Heat Dissipation
Wide V
IN
Range: 4.5V to 60V (65V Abs Max);
Operates Down to 2.3V After Start-Up
Output Voltage Up to 60V
±1% 1.200V Reference Voltage
R
SENSE
or Inductor DCR Current Sensing
100% Duty Cycle Capability for Synchronous MOSFET
Low Quiescent Current: 28μA
Phase-Lockable Frequency (75kHz to 850kHz)
Programmable Fixed Frequency (50kHz to 900kHz)
Power Good Output Voltage Monitor
Low Shutdown Current: 4µA
Internal LDO Powers Gate Drive from VBIAS or EXTV
CC
Thermally Enhanced Low Profile 24-Pin 4mm × 4mm
QFN Package and 20-Lead TSSOP Package
APPLICATIONS
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Industrial
Automotive
Medical
Military
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
PLLIN/MODE
FREQ
OVMODE
ILIM
PGOOD
GND
INTV
CC
VFB
EXTV
CC
3769 TA01a
Efficiency and Power Loss
vs Output Current
220µF
V
OUT
24V/5A
100
90
EFFICIENCY
EFFICIENCY (%)
V
OUT
FOLLOWS V
IN
FOR V
IN
> 24V
80
70
60
0.01
50
40
0.0001
0.001
POWER
LOSS
0.1
1
POWER LOSS (W)
10
4m
3.3µH
VBIAS
RUN
SS
LTC3769
ITH
SENSE
+
SENSE
–
BG
TG
SW
0.1µF
BOOST
0.1
1
0.001
0.01
OUTPUT CURRENT (A)
10
3769 TA01b
4.7µF
232k
12.1k
3769fa
For more information
www.linear.com/LTC3769
1
LTC3769
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 3)
VBIAS ........................................................ –0.3V to 65V
BOOST ........................................................–0.3V to 71V
SW ................................................................ –5V to 65V
RUN ............................................................. –0.3V to 8V
Maximum Current Sourced into Pin
From Source >8V ..............................................100µA
PGOOD, PLLIN/MODE ................................. –0.3V to 6V
INTV
CC
, (BOOST - SW) ..................................–0.3V to 6V
EXTV
CC
...................................................... –0.3V to 14V
SENSE
+
, SENSE
–
........................................ –0.3V to 65V
(SENSE
+
- SENSE
–
) ............................................–0.3V to 0.3V
ILIM, SS, ITH, FREQ, PHASMD, VFB ..... –0.3V to INTV
CC
Operating Junction Temperature
Range (Note 2)........................................–55°C to 150°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec) SSOP ........ 300°C
PIN CONFIGURATION
TOP VIEW
INTV
CC
BOOST
GND
TOP VIEW
ILIM
INTV
CC
FREQ
GND
PLLIN/MODE
RUN
SS
SENSE
–
SENSE
+
1
2
3
4
5
6
7
8
9
21
GND
20 PGOOD
19 VBIAS
18 EXTV
CC
17 INTV
CC
16 BG
15 BOOST
14 TG
13 SW
12 OVMODE
11 ITH
VBIAS 1
PGOOD 2
ILIM 3
NC 4
INTV
CC
5
NC 6
7
FREQ
8
GND
9 10 11 12
PLLIN/MODE
GND
RUN
SS
25
GND
EXTV
CC
BG
24 23 22 21 20 19
18 SW
17 OVMODE
16 ITH
15 VFB
14 SENSE
+
13 SENSE
–
VFB 10
FE PACKAGE
20-LEAD PLASTIC TSSOP
T
JMAX
= 150°C,
θ
JA
= 38°C/W
EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB
UF PACKAGE
24-LEAD (4mm
×
4mm) PLASTIC QFN
T
JMAX
= 150°C,
θ
JA
= 47°C/W
EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC3769EUF#PBF
LTC3769IUF#PBF
LTC3769HUF#PBF
LTC3769MPUF#PBF
LTC3769EFE#PBF
LTC3769IFE#PBF
LTC3769HFE#PBF
LTC3769MPFE#PBF
TAPE AND REEL
LTC3769EUF#TRPBF
LTC3769IUF#TRPBF
LTC3769HUF#TRPBF
LTC3769MPUF#TRPBF
LTC3769EFE#TRPBF
LTC3769IFE#TRPBF
LTC3769HFE#TRPBF
LTC3769MPFE#TRPBF
PART MARKING*
3769
3769
3769
3769
LTC3769FE
LTC3769FE
LTC3769FE
LTC3769FE
PACKAGE DESCRIPTION
24-Lead (4mm
×
4mm) Plastic QFN
24-Lead (4mm
×
4mm) Plastic QFN
24-Lead (4mm
×
4mm) Plastic QFN
24-Lead (4mm
×
4mm) Plastic QFN
20-Lead Plastic SSOP
20-Lead Plastic SSOP
20-Lead Plastic SSOP
20-Lead Plastic SSOP
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 150°C
–55°C to 150°C
–40°C to 125°C
–40°C to 125°C
–40°C to 150°C
–55°C to 150°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
3769fa
2
For more information
www.linear.com/LTC3769
TG
LTC3769
ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
Main Control Loop
VBIAS
Chip Bias Voltage Operating Range
SENSE Pins Common Mode Range (BOOST
V
IN
Converter Input Supply Voltage)
Regulated Output Voltage Range
V
OUT
Regulated Feedback Voltage
V
FB
Feedback Current
Reference Line Voltage Regulation
Output Voltage Load Regulation
(Note 4)
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
