mode boost and SEPIC controller that drives N-channel
power MOSFETs. Two phase operation reduces system
filtering capacitance and inductance requirements. The 10V
gate drive is optimized for most automotive and industrial
grade power MOSFETs.
Adjustable slope compensation gain allows the user to fine-
tune the current loop gain, improving noise immunity.
The operating frequency can be set with an external resistor
over a 75kHz to 500kHz range and can be synchronized
to an external clock using the internal PLL. Multi-phase
operation is possible using the SYNC input, the CLKOUT
output and the PHASEMODE control pin allowing 2-, 3-,
4-, 6- or 12-phase operation.
Other features include an internal 10V LDO with
undervoltage lockout protection for the gate drivers, a
precision RUN pin threshold with programmable hyster-
esis, soft-start and programmable leading edge blanking
and maximum duty cycle. The LTC3862 is a 5V gate drive
version of the LTC3862-1.
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Protected by U.S. Patents,
including 6144194, 6498466, 6611131.
Wide V
IN
Range: 8.5V to 36V Operation
2-Phase Operation Reduces Input and Output
Capacitance
Fixed Frequency, Peak Current Mode Control
10V Gate Drive for High Voltage MOSFETs
Adjustable Slope Compensation Gain
Adjustable Max Duty Cycle (Up to 96%)
Adjustable Leading Edge Blanking
±1% Internal Voltage Reference
Programmable Operating Frequency with One
External Resistor (75kHz to 500kHz)
Phase-Lockable Fixed Frequency 50kHz to 650kHz
SYNC Input and CLKOUT for 2-, 3-, 4-, 6- or
12-Phase Operation (PHASEMODE Programmable)
Internal 10V LDO Regulator
24-Lead Narrow SSOP Package
5mm
×
5mm QFN Package with 0.65mm Lead Pitch
24-Lead Thermally Enhanced TSSOP Package
APPLICATIONS
n
Automotive, Telecom and Industrial Power Supplies
TYPICAL APPLICATION
150k
24.9k
RUN
INTV
CC
4.7μF
45.3k
V
IN
GATE1
SENSE1
+
EFFICIENCY (%)
110μF
0.020Ω 100V
56μH
56μH
22μF
50V
V
IN
8.5V TO 36V
Efficiency vs Output Current
V
OUT
72V
2A (MAX)
100
98
96
94
92
90
88
86
84
82
80
100
1000
LOAD CURRENT (mA)
10000
38621 TA01b
V
OUT
= 72V
V
IN
= 32V
V
IN
= 24V
LTC3862-1
BLANK
SENSE1
–
FREQ
GATE2
SYNC
SENSE2
+
PLLFLTR
V
IN
= 9V
0.1μF
1nF
0.020Ω
SS
3V8
FB
ITH
SENSE2
–
PGND
CLKOUT
SLOPE
D
MAX
PHASEMODE
SGND
38621 TA01a
1.5nF
324k
5.62k
45.3k
100pF
38621f
1
LTC3862-1
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
Input Supply Voltage (V
IN
) ......................... –0.3V to 40V
INTV
CC
Voltage .......................................... –0.3V to 11V
INTV
CC
LDO RMS Output Current .........................50mA
RUN Voltage ................................................ –0.3V to 8V
SYNC Voltage ............................................... –0.3V to 6V
SLOPE, PHASEMODE, D
MAX
,
BLANK Voltage ........................................... –0.3V to 3V8
SENSE1
+
, SENSE1
–
, SENSE2
+
,
SENSE2
–
Voltage ....................................... –0.3V to 3V8
SS, PLLFLTR Voltage ................................. –0.3V to 3V8
ITH Voltage ............................................... –0.3V to 2.7V
FB Voltage .................................................. –0.3V to 3V8
FREQ Voltage ............................................ –0.3V to 1.5V
Operating Junction Temperature Range (Notes 3, 4)
LTC3862-1E ......................................... –40°C to 85°C
LTC3862-1I ........................................ –40°C to 125°C
LTC3862-1H ....................................... –40°C to 150°C
Storage Temperature Range................... –65°C to 150°C
Reflow Peak Body Temperature ........................... 260°C
PIN CONFIGURATION
TOP VIEW
D
MAX
SLOPE
BLANK
PHASEMODE
FREQ
SS
ITH
FB
SGND
1
2
3
4
5
6
7
8
9
25
24 3V8
23 SENSE1
+
22
SENSE1
–
D
MAX
SLOPE
BLANK
PHASEMODE
FREQ
SS
ITH
FB
SGND
1
2
3
4
5
6
7
8
9
TOP VIEW
SLOPE
24 3V8
23 SENSE1
+
22 SENSE1
–
21 RUN
20 V
IN
19 INTV
CC
18 GATE1
17 PGND
16 GATE2
15 NC
14 SENSE2
–
13 SENSE2
+
BLANK 1
PHASEMODE 2
FREQ 3
SS 4
ITH 5
FB 6
7
SGND
8
CLKOUT
9 10 11 12
SYNC
PLLFLTR
SENSE2
+
SENSE2
–
25
TOP VIEW
SENSE1
+
SENSE1
–
DMAX
RUN
18 V
IN
17 INTV
CC
16 GATE1
15 PGND
14 GATE2
13 NC
3V8
24 23 22 21 20 19
21 RUN
20 V
IN
19 INTV
CC
18 GATE1
17 PGND
16 GATE2
15 NC
14
13
SENSE2
–
SENSE2
+
CLKOUT 10
SYNC 11
PLLFLTR 12
CLKOUT 10
SYNC 11
PLLFLTR 12
FE PACKAGE
24-LEAD PLASTIC TSSOP
T
JMAX
= 150°C,
θ
JA
= 38°C/W
EXPOSED PAD (PIN 25) IS PGND, MUST BE SOLDERED TO PCB
GN PACKAGE
24-LEAD NARROW PLASTIC SSOP
T
JMAX
= 150°C,
θ
JA
= 85°C/W
UH PACKAGE
24-LEAD (5mm 5mm) PLASTIC QFN
T
JMAX
= 150°C,
θ
JA
= 34°C/W
EXPOSED PAD (PIN 25) IS PGND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC3862EFE-1#PBF
LTC3862IFE-1#PBF
LTC3862HFE-1#PBF
LTC3862EGN-1#PBF
LTC3862IGN-1#PBF
LTC3862HGN-1#PBF
TAPE AND REEL
LTC3862EFE-1#TRPBF
LTC3862IFE-1#TRPBF
LTC3862HFE-1#TRPBF
LTC3862EGN-1#TRPBF
LTC3862IGN-1#TRPBF
LTC3862HGN-1#TRPBF
PART MARKING*
LTC3862FE-1
LTC3862FE-1
LTC3862FE-1
LTC3862GN-1
LTC3862GN-1
LTC3862GN-1
PACKAGE DESCRIPTION
24-Lead Plastic TSSOP
24-Lead Plastic TSSOP
24-Lead Plastic TSSOP
24-Lead Plastic SSOP
24-Lead Plastic SSOP
24-Lead Plastic SSOP
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 125°C
–40°C to 150°C
–40°C to 85°C
–40°C to 125°C
–40°C to 150°C
38621f
2
LTC3862-1
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC3862EUH-1#PBF
LTC3862EUH-1#TRPBF
38621
24-Lead (5mm
×
5mm) Plastic QFN
–40°C to 85°C
LTC3862IUH-1#PBF
LTC3862IUH-1#TRPBF
38621
24-Lead (5mm
×
5mm) Plastic QFN
–40°C to 125°C
LTC3862HUH-1#PBF
LTC3862HUH-1#TRPBF
38621
24-Lead (5mm
×
5mm) Plastic QFN
–40°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.
Consult LTC Marketing for information on non-standard lead based finish parts.
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/
ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
Supply Input and INTV
CC
Linear Regulator
V
IN
Supply Voltage Range
V
IN
V
IN
Supply Current
I
VIN
Normal Mode, No Switching
Shutdown
LDO Regulator Output Voltage
INTV
CC
dV
INTVCC(LINE)
Line Regulation
dV
INTVCC(LOAD)
Load Regulation
INTV
CC
UVLO Voltage
V
UVLO
3V8
LDO Regulator Output Voltage
Switcher Control Loop
Reference Voltage
V
FB
dV
FB
/dV
IN
dV
FB
/dV
ITH
g
m
f
0dB
V
ITH
Feedback Voltage V
IN
Line Regulation
Feedback Voltage Load Regulation
Transconductance Amplifier Gain
Error Amplifier Unity-Gain Crossover
Frequency
Error Amplifier Maximum Output Voltage
(Internally Clamped)
Error Amplifier Minimum Output Voltage
Error Amplifier Output Source Current
Error Amplifier Output Sink Current
Error Amplifier Input Bias Currents
Pulse Skip Mode Operation ITH Pin Voltage
SENSE Pin Current
Maximum Current Sense Input Threshold
CH1 to CH2 Maximum Current Sense
Threshold Matching
(Notes 2, 3) The
l
denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, RUN = 2V and SS = open, unless otherwise noted.
CONDITIONS
l
MIN
8.5
TYP
MAX
36
UNITS
V
mA
μA
V
%/V
%
V
V
V
V
V
%/V
%
μMho
MHz
V
mV
μA
μA
nA
V
mV
μA
mV
mV
mV
(Note 5)
V
RUN
= 0V
12V < V
IN
< 36V
Load = 0mA to 20mA
Rising INTV
CC
Falling INTV
CC
l
l
9.5
–2
1.8
30
10.0
0.002
7.5
7.0
3.8
3.0
80
10.5
0.02
V
ITH
= 0.8V (Note 6)
E-Grade (Note 3)
I-Grade and H-Grade (Note 3)
V
IN
= 8.5V to 36V (Note 6)
V
ITH
= 0.5V to 1.2V (Note 6)
V
ITH
= 0.8V (Note 6), ITH Pin Load = ±5μA
(Note 7)
V
FB
= 1V, No Load
V
FB
= 1.5V, No Load
l
l
1.210
1.199
1.223
1.223
±0.002
0.01
660
1.8
2.7
50
–30
30
–50
0.275
25
0.01
75
75
1.235
1.248
0.01
0.1
I
ITH
I
FB
V
ITH(PSKIP)
I
SENSE(ON)
V
SENSE(MAX)
V
SENSE(MATCH)
(Note 6)
Rising ITH Voltage (Note 6)
Hysteresis
V
SLOPE
= Float, Low Duty Cycle
(Note 3)
V
SLOPE
= Float, Low Duty Cycle (Note 3)
(V
SENSE1
– V
SENSE2
)
65
60
–10
–200
l
l
2
85
90
10
38621f
3
LTC3862-1
ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
RUN/Soft-Start
RUN Source Current
I
RUN
V
RUN
V
RUNHYS
I
SS
R
SS
Oscillator
f
OSC
High Level RUN Channel Enable Threshold
RUN Threshold Hysteresis
SS Pull-Up Current
SS Pull-Down Resistance
Oscillator Frequency
Oscillator Frequency Range
Nominal FREQ Pin Voltage
SYNC Minimum Input Frequency
SYNC Maximum Input Frequency
SYNC Input Threshold
Phase Detector Sourcing Output Current
Phase Detector Sinking Output Current
Channel 1 to Channel 2 Phase Relationship
(Notes 2, 3) The
l
denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, RUN = 2V and SS = open, unless otherwise noted.
CONDITIONS
V
RUN
= 0V
V
RUN
= 1.5V
MIN
TYP
–0.5
–5
1.22
80
–5
10
280
260
75
300
300
1.223
l
l
MAX
UNITS
μA
μA
V
mV
μA
kΩ
V
SS
= 0V
V
RUN
= 0V
R
FREQ
= 45.6k
R
FREQ
= 45.6k
R
FREQ
= 45.6k
V
SYNC
= External Clock
V
SYNC
= External Clock
Rising Threshold
f
SYNC
> f
OSC
f
SYNC
< f
OSC
V
PHASEMODE
= 0V
V
PHASEMODE
= Float
V
PHASEMODE
= 3V8
V
PHASEMODE
= 0V
V
PHASEMODE
= Float
V
PHASEMODE
= 3V8
V
DMAX
= 0V
V
DMAX
= Float
V
DMAX
= 3V8
V
BLANK
= 0V (Note 8)
V
BLANK
= Float (Note 8)
V
BLANK
= 3V8 (Note 8)
l
l
320
340
500
50
V
FREQ
f
SYNC
V
SYNC
I
PLLFLTR
CH1-CH2
650
1.5
–15
15
180
180
120
90
60
240
96
84
75
210
290
375
3
0.9
CH1-CLKOUT
Channel 1 to CLKOUT Phase Relationship
D
MAX
Maximum Duty Cycle
t
ON(MIN)1
t
ON(MIN)2
t
ON(MIN)3
Gate Driver
R
DS(ON)
Overvoltage
V
FB(OV)
Minimum On-Time
Minimum On-Time
Minimum On-Time
Driver Pull-Up R
DS(ON)
Driver Pull-Down R
DS(ON)
V
FB
, Overvoltage Lockout Threshold
kHz
kHz
kHz
V
kHz
kHz
V
μA
μA
Deg
Deg
Deg
Deg
Deg
Deg
%
%
%
ns
ns
ns
Ω
Ω
V
FB(OV)
– V
FB(NOM)
in Percent
8
10
12
%
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:
All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to ground unless otherwise
specified.
Note 3:
The LTC3862E-1 is guaranted to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls. The LTC3862I-1 is guaranteed over the
full –40°C to 125°C operating temperature range and the LTC3862H-1 is
guaranteed over the full –40°C to 150°C operating temperature range.
High junction temperatures degrade operating lifetimes. Operating lifetime
is derated at junction temperatures greater than 125°C.
Note 4:
This IC includes overtemperature protection that is intended to
protect the device during momentary overload conditions. Continuous
operation above the specified maximum operating junction temperature
may impair device reliability.
Note 5:
Supply current in normal operation is dominated by the current
needed to charge the external MOSFET gates. This current will vary with
supply voltage and the external MOSFETs used.
Note 6:
The IC is tested in a feedback loop that adjusts V
FB
to achieve a
specified error amplifier output voltage.
Note 7:
Guaranteed by design, not subject to test.
Note 8:
The minimum on-time condition is specified for an inductor peak-
to-peak ripple current = 30% (see Minimum On-Time Considerations in the
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