FEATURES
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LTC3777
150V V
IN
and V
OUT
Synchronous
4-Switch Buck-Boost Controller +
Switching Bias Supply
DESCRIPTION
The
LTC
®
3777
is a high performance buck-boost switching
regulator controller that operates from input voltages
above, below or equal to the output voltage. The constant
frequency current mode architecture allows a phase-lockable
frequency of up to 600kHz, while an input/output constant
current loop provides support for battery charging. The
150V integrated switching bias supply is a high efficiency
step-down regulator that draws only 12µA typical DC supply
current with a regulated output voltage at no load.
With a wide 4.5V to 150V input and output range and
seamless transfers between operating regions, the
LTC3777 is ideal for industrial, telecom and battery-
powered systems.
The LTC3777 features a power good output indicator
and a MODE pin to select between pulse-skipping mode
or forced continuous mode of operation. The PLLIN pin
allows the IC to be synchronized to an external clock. The
SS pin ramps the output voltage during start-up. Current
foldback limits MOSFET heat dissipation during short-
circuit conditions.
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4-Switch Current Mode Single Inductor Architecture
Allows V
IN
Above, Below or Equal to V
OUT
Wide V
IN
Range: 4.5V to 150V
Wide Output Voltage Range: 1.2V ≤ V
OUT
≤ 150V
Synchronous Rectification: Up to 99% Efficiency
±1% 1.2V Voltage Reference
Input or Output Average Current Limit
Integrated 12µA I
Q
, 150V, 85mA, Switching Bias
for Optimal Thermal Performance
Programmable 6V to 10V DRV
CC
Optimizes Efficiency
No Top FET Refresh Noise in Boost or Buck Mode
V
OUT
Disconnected from V
IN
During Shutdown
Phase-Lockable Fixed Frequency (50kHz to 600kHz)
No Reverse Current During Start-Up
150V Rated RUN Pin with Accurate Turn-On Threshold
Thermally Enhanced 48-Lead e-LQFP Package
APPLICATIONS
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Industrial, Transportation, Medical, Military, Avionics
All registered trademarks and trademarks are the property of their respective owners.
TYPICAL APPLICATION
V
IN
16V TO 120V
20µF
1k
5µF
5
0.1µF
133k
10µF
V
INOV
1.21k
BV
IN
BOV
BRUN
220µH
715k
BSW
BV
FB
BGND
EXTV
CC
RUN
PGOOD
V5
SS
FREQ
SENSEP
SENSEN
SGND
PGND
BG2
BOOST2
0.22µF
SW2
TG2
I
AVGSNSP
I
AVGSNSN
V
OUTSNS
V
FB
ITH
MODE
PLLIN
1k
100pF
4.7µF
100
100
92
V
OUT
= 48V
I
OUT
= 10A
0
POWER LOSS
6
4m
30µF
V
INSNS
V
IN
DRV
CC
LTC3777
BOOST1
SW1
TG1
BG1
100
15µH
0.22µF
V
OUT
48V, 10A
56µF
Efficiency and Power Loss
vs Input Voltage
100
30
98
EFFICIENCY (%)
24
POWER LOSS (W)
1µF
BV
OUT
12V
85mA
44µF
220pF
100
4m
475k
EFFICIENCY
96
18
94
12
51.1k
10k
2.2µF
1µF
90
0
12 24 36 48 60 72 84 96 108 120
VIN VOLTAGE (V)
3777 TA01b
100k
0.1µF
56.2k
12.1k
10k
10nF
3777 TA01a
3777f
For more information
www.linear.com/LTC3777
1
LTC3777
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
V
FB
SS
V5
DRV
CC
EXTV
CC
DRVSET
VINOV
BG1
NC
SW1
TG1
BOOST1
BRUN 1
NC 2
BSW 3
NC 4
BV
IN
5
NC 6
BOV 7
BFBO 8
NC 9
BGND 10
BI
SET
11
BV
FB
12
48
47
46
45
44
43
42
41
40
39
38
37
Input Supply Voltage (V
IN
), BV
IN
.............. 150V to –0.3V
Topside Driver Voltage
BOOST1, BOOST2 .....................................161V to –0.3V
Switch Voltage SW1, SW2 .......................... 150V to –5V
RUN, BRUN .............................................. 150V to –0.3V
I
AVGSNSP
, I
AVGSNSN
....................................150V to –10V
V
INSNS
, V
OUTSNS
...................................... 150V to –0.3V
EXTV
CC
Voltage ........................................ 36V to –0.3V
DRV
CC
Voltage ............................................11V to –0.3V
BOOST1-SW1, BOOST2-SW2......................11V to –0.3V
TG1-SW1, TG2-SW2, BG1, BG2.......................... (Note 8)
V5, BOV, BFBO, BV
FB
, BI
SET
Voltage ............ 6V to –0.3V
MODE, PLLIN, SS, PGOOD .......................... V5 to –0.3V
ITH, FREQ, DRVSET ..................................... V5 to –0.3V
SENSEP, SENSEN, VINOV ............................ V5 to –0.3V
V
FB
Voltage ............................................... 2.7V to –0.3V
Operating Junction Temperature
Range (Notes 2, 3) ................................. –40°C to 150°C
Storage Temperature Range .................. –65°C to 150°C
EXTV
CC
/DRV
CC
Peak Current ..............................100mA
49
PGND
36
35
34
33
32
31
30
29
28
27
26
25
V
IN
NC
V
INSNS
NC
V
OUTSNS
NC
I
AVGSNSN
I
AVGSNSP
NC
RUN
NC
BOOST2
LXE PACKAGE
48-LEAD (7mm
×
7mm) PLASTIC e-LQFP
T
JMAX
= 150°C,
θ
JA
= 36°C/W
EXPOSED PAD (PIN 49) IS PGND, MUST BE SOLDERED TO PCB
FOR RATED ELECTRICAL AND THERMAL CHARACTERISTICS
ORDER INFORMATION
LEAD FREE FINISH
LTC3777ELXE#PBF
LTC3777ILXE#PBF
LTC3777 LXE
LTC3777 LXE
http://www.linear.com/product/LTC3777#orderinfo
PACKAGE DESCRIPTION
48-Lead (7mm × 7mm) Plastic e-LQFP
48-Lead (7mm × 7mm) Plastic e-LQFP
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
PART MARKING
Consult ADI Marketing for parts specified with wider operating temperature ranges.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
LXE package and tray drawings:
http://www.linear.com/packaging
SENSEP 13
SENSEN 14
ITH 15
SGND 16
MODE 17
PLLIN 18
FREQ 19
PGOOD 20
BG2 21
NC 22
SW2 23
TG2 24
3777f
2
For more information
www.linear.com/LTC3777
LTC3777
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2), V
IN
= 15V, V
RUN
= 5V, V
EXTVCC
= 0V, V
DRVSET
= 0V,
V
VINOV
= 0V unless otherwise noted.
SYMBOL
V
IN
V
OUT
PARAMETER
Input Supply Operating Voltage Range
Output Supply Operating Voltage Range
Regulated Feedback Voltage
Feedback Current
Reference Voltage Line Regulation
Output Voltage Load Regulation
Transconductance Amplifier gm
I
Q
Input DC Supply Current
Shutdown
Undervoltage Lockout
RUN Pin ON Threshold
RUN Pin Hysteresis
RUN Pin Source Current
RUN Pin Hysteresis Current
V
IN
Overvoltage Lockout Threshold
(Rising)
V
IN
Overvoltage Hysteresis
SENSE Pins Current
I
AVGSNSP
I
AVGSNSN
V
SENSE(MAX)
I
AVGSNS
Pins Current
Soft-Start Charge Current
Maximum Current Sense Threshold
(Buck Region Valley Current Mode)
Maximum Current Sense Threshold
(Boost Region Peak Current Mode)
Maximum Input / Output Average
Current Sense Threshold
DC
(MAX, BOOST)
DC
(MIN, BOOST)
DC
(MIN, BUCK)
Gate Driver
TG Pull-Up On Resistance
TG Pull-Down On Resistance
BG Pull-Up On Resistance
BG Pull-Down On Resistance
TG Transition Time:
Rise Time
Fall Time
BG Transition Time:
Rise Time
Fall Time
V
DRVCC
= 6V
V
DRVCC
= 6V
V
DRVCC
= 6V (Note 7)
C
LOAD
= 3300pF
V
DRVCC
= 6V (Note 7)
C
LOAD
= 3300pF
3.1
1.5
5.5
3
60
Ω
Ω
Maximum Duty Factor
V
SENSEP
= V
SENSEN
= 0
V
IAVGSNSP
= V
IAVGSNSN
= 10V
V
SS
= 0V
V
FB
= 1V
V
FB
= 1V
V
IAVGSNSP
= V
IAVGSNSN
= 10V, V
FB
= 1V
% Switch C On
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ELECTRICAL CHARACTERISTICS
CONDITIONS
(Note 4)
(Note 5); ITH Voltage = 1.4V
(Note 5)
(Note 5); V
IN
= 7V to 100V
(Note 5); Measured in Servo Loop; ∆ITH
Voltage = 1.5V to 2V
(Note 5); ITH = 1.4V; Sink/Source 5µA
(Note 6)
RUN = 0V
V5 Ramping Up
V5 Ramping Down
V
RUN
Rising
V
RUN
< 1.2V
V
RUN
> 1.2V
V
VINOV
Rising
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MIN
4.5
1.2
1.188
TYP
MAX
150
150
UNITS
V
V
V
nA
%
%
mmho
1.2
–15
0.02
0.01
1.5
3.6
40
1.212
-50
0.2
0.2
5.5
75
4.6
4.1
1.3
mA
µA
V
V
V
mV
µA
µA
4.1
3.6
1.1
4.35
3.85
1.2
100
2.5
6.5
1.18
1.28
50
1.38
V
mV
±2
15
4
70
120
47.5
5
90
140
50
90
9
9
6
110
160
52.5
µA
µA
µA
mV
mV
mV
%
%
%
Minimum Duty Factor for Main Switch in % Switch C On
Boost Operation
Minimum Duty Factor for Main Switch in % Switch B On
Buck Operation
ns
60
ns
3777f
For more information
www.linear.com/LTC3777
3
LTC3777
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2), V
IN
= 15V, V
RUN
= 5V, V
EXTVCC
= 0V, V
DRVSET
= 0V,
V
VINOV
= 0V unless otherwise noted.
SYMBOL
PARAMETER
Top Gate Off to Bottom Gate On Delay
Synchronous Switch-On Delay Time
Bottom Gate Off to Top Gate On Delay
Top Switch-On Delay Time
DRV
CC
LDO Regulator
V
DRVCC
DRV
CC
Regulation Voltage from Internal
V
IN
LDO
V
EXTVCC
= 0V
7V < V
IN
< 150V, V
DRVSET
= 0V
8V < V
IN
< 150V, V
DRVSET
= 1/4 V
V5
9V < V
IN
< 150V, V
DRVSET
= Float
10V < V
IN
< 150V, V
DRVSET
= 3/4 V
V5
11V < V
IN
< 150V, V
DRVSET
= V
V5
I
CC
= 0mA to 50mA, V
EXTVCC
= 0V
7V < V
EXTVCC
< 30V, V
DRVSET
= 0V
8V < V
EXTVCC
< 30V, V
DRVSET
= 1/4 V
V5
9V < V
EXTVCC
< 30V, V
DRVSET
= Float
10V < V
EXTVCC
< 30V, V
DRVSET
= 3/4 V
V5
11V < V
EXTVCC
< 30V, V
DRVSET
= V
V5
I
CC
= 0mA to 50mA, V
EXTVCC
= 12V
V
DRVSET
= 0V
EXTV
CC
Ramping Positive
% of DRV
CC
Regulation Voltage
6V < V
DRVCC
< 10V
I
V5
= 0mA to 20mA, V
DRVCC
= 7V
R
FREQ
= 68.5kΩ
R
FREQ
≤ 20kΩ
R
FREQ
= 135kΩ
V
PLLIN
Rising
V
PLLIN
Falling
PLLIN = External Clock
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ELECTRICAL CHARACTERISTICS
CONDITIONS
C
LOAD
= 3300pF Each Driver, V
DRVCC
= 6V
C
LOAD
= 3300pF Each Driver, V
DRVCC
= 6V
MIN
TYP
60
60
MAX
UNITS
ns
ns
5.5
6.5
7.5
8.45
9.15
5.8
6.8
7.8
8.75
9.65
5.8
6.8
7.8
8.8
9.5
0.5
6.1
7.1
8.1
9.1
10
0.5
DRV
CC
– 0.5
10
6.1
7.1
8.1
9.15
9.85
2
6.4
7.4
8.4
9.45
10.35
2
V
V
V
V
V
%
V
V
V
V
V
%
V
%
V
EXTVCC
DRV
CC
Load Regulation from V
IN
LDO
DRV
CC
Regulation Voltage from Internal
EXTV
CC
LDO
DRV
CC
Load Regulation from Internal
EXTV
CC
LDO
EXTV
CC
LDO Switchover Voltage
EXTV
CC
Hysteresis
V5 Linear Regulator
V5 Regulation Voltage
V5 Load Regulation
Oscillator and Phase-Locked Loop
Nominal Frequency
Low Fixed Frequency
High Fixed Frequency
PLLIN Input Threshold
PLLIN Input Resistance
Synchronizable Oscillator Frequency
I
FREQ
PGOOD Output
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level
Frequency Setting Current
5.3
5.5
0.5
5.7
1
275
50
550
1.2
V
%
kHz
kHz
kHz
V
V
kΩ
kHz
µA
V
µA
%
%
µs
225
30
450
2
250
40
500
200
50
18
20
0.1
600
22
0.3
±1
–10
10
125
I
PGOOD
= 2mA
V
PGOOD
= 5.5V
V
FB
with Respect to Set Regulated Voltage
V
FB
Ramping Negative
V
FB
Ramping Positive
PGOOD delay
V
PGOOD
High to Low
3777f
4
For more information
www.linear.com/LTC3777
LTC3777
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 12V, unless otherwise noted.
SYMBOL
V
BVIN
V
BVOUT
BUVLO
PARAMETER
Input Voltage Operating Range
Output Voltage Operating Range
BV
IN
Undervoltage Lockout
DC Supply Current (Note 6)
Active Mode
Sleep Mode
Shutdown Mode
BRUN Pin Threshold
BV
IN
Rising
BV
IN
Falling
Hysteresis
CONDITIONS
MIN
4
0.8
3.5
3.3
3.8
3.6
250
150
12
1.4
1.1
0.99
–10
1.1
0.99
1.2
1.09
110
0
1.2
1.09
110
0.800
5
0
240
25
0.1
1
TYP
MAX
150
V
IN
4.15
3.95
UNITS
V
V
V
V
mV
µA
µA
µA
V
V
mV
nA
V
V
mV
V
mV
nA
mA
mA
μA
ms
Switching Bias Supply
ELECTRICAL CHARACTERISTICS
I
QB
No Load
BV
RUN
= 0V
BRUN Rising
BRUN Falling
Hysteresis
BRUN = 1.3V (Note 9)
BOV Rising
BOV Falling
Hysteresis
BV
FB
Rising
BV
FB
Falling
BV
FB
= 1V (Note 9)
BI
SET
Floating
BI
SET
Shorted to GND
BV
IN
= 150V, BSW = 0V
(Note 9)
350
22
6
1.3
1.19
10
1.3
1.19
V
BRUN
I
BRUN
V
BOV
BRUN Pin Leakage Current
BOV Pin Threshold
Output Supply (BV
FB
)
V
BVFB
V
BVFBH
I
BVFB
Operation
I
PEAKB
I
LBSWB
t
INT(SS)B
Peak Current Comparator Threshold
Switch Pin Leakage Current
Internal Soft-Start Time
170
17
310
33
1
Feedback Comparator Threshold
Feedback Comparator Hysteresis
Feedback Pin Current
0.786
3
–10
0.814
9
10
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
The LTC3777 is tested under pulsed load conditions such that T
J
≈ T
A
. The LTC3777E is guaranteed to meet performance specifications
from 0°C to 85°C junction temperature. Specifications over the –40°C
to 125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LTC3777I is guaranteed over the full –40°C to 125°C operating junction
temperature range. Note that the maximum ambient temperature
consistent with these specifications is determined by specific operating
conditions in conjunction with board layout, the rated package thermal
impedance and other environmental factors. The junction temperature T
J
is calculated from the ambient temperature T
A
and power dissipation P
D
according to the formula:
T
J
= T
A
+ (P
D
•
θ
JA
),
where
θ
JA
= 36°C/W for the e-LQFP package.
Note 3:
This IC includes over temperature protection that is intended to
protect the device during momentary overload conditions. The maximum
rated junction temperature will be exceeded when this protection is active.
Continuous operation above the specified absolute maximum operating
junction temperature may impair device reliability or permanently damage
the device.
Note 4:
When biased from an auxiliary supply through the EXTV
CC
pin, the
LTC3777 can operate from a V
IN
voltage lower than 4.5V. Otherwise the
minimum V
IN
operational voltage is 4.5V after startup.
Note 5:
The LTC3777 is tested in a feedback loop that servos V
ITH
to a
specified voltage and measures the resultant V
FB
.
Note 6:
Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications information.
Note 7:
Rise and fall times are measured using 10% and 90% levels.
Delay times are measured using 50% levels.
Note 8:
Do not apply a voltage or current source to these pins. They must
be connected to capacitive loads only, otherwise permanent damage may
occur. These pins are rated for an absolute maximum voltage of –0.3V
to 11V.
Note 9:
Guaranteed by design and wafer level measurements.
3777f
For more information
www.linear.com/LTC3777
5
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