Peak Output Current ................................150mA
Operating Junction Temperature Range (Note 3)
E-Grade, I-Grade ................................ –40°C to 125°C
H-Grade ............................................. –40°C to 150°C
MP-Grade .......................................... –55°C to 150°C
Storage Temperature Range .................. –65°C to 150°C
(Note 1)
PIN CONFIGURATION
TOP VIEW
FREQ/PLLFLTR
MODE/PLLIN
BOOST1
TK/SS1
RUN1
RUN2
RUN3
40 39 38 37 36 35 34 33 32 31
TK/SS2 1
TK/SS3 2
SENSE1
+
SW1
30 BG1
29 DRV
CC12
28 BG2
27 SW2
26 TG2
25 BOOST2
24 V
IN
23 EXTV
CC
22 INTV
CC
21 BG3
SW3
I
LIM
3
4
5
6
7
8
41
SENSE1
–
SENSE2
+
SENSE2
–
SENSE3
+
SENSE3
–
V
FB1
9
I
TH1
10
11 12 13 14 15 16 17 18 19 20
SGND
PGOOD3
PGOOD12
BOOST3
V
FB2
V
FB3
I
TH2
I
TH3
TG3
UJ PACKAGE
40-LEAD (6mm
×
6mm) PLASTIC QFN
T
JMAX
= 150°C,
θ
JA
= 33°C/W
EXPOSED PAD (PIN 41) IS PGND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC3853EUJ#PBF
LTC3853IUJ#PBF
LTC3853HUJ#PBF
LTC3853MPUJ#PBF
TAPE AND REEL
LTC3853EUJ#TRPBF
LTC3853IUJ#TRPBF
LTC3853HUJ#TRPBF
LTC3853MPUJ#TRPBF
PART MARKING*
LTC3853UJ
LTC3853UJ
LTC3853UJ
LTC3853UJ
PACKAGE DESCRIPTION
40-Lead (6mm × 6mm) Plastic QFN
40-Lead (6mm × 6mm) Plastic QFN
40-Lead (6mm × 6mm) Plastic QFN
40-Lead (6mm × 6mm) Plastic QFN
TEMPERATURE RANGE
–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/
TG1
3853fc
2
For more information
www.linear.com/LTC3853
LTC3853
ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
Output Voltage Range
V
FB1,2,3
Regulated Feedback Voltage
Main Control Loops
Channels 1, 2
Channel 3
I
TH1,2,3
Voltage = 1.2V, –55°C to 150°C (Note 4)
I
TH1,2,3
Voltage = 1.2V, –40°C to 125°C (Note 4)
I
TH1,2,3
Voltage = 1.2V, 0°C to 85°C (Note 4)
(Note 4)
V
IN
= 6V to 24V (Note 4)
(Note 4)
Measured in Servo Loop;
DI
TH
Voltage = 1.2V to 0.7V
Measured in Servo Loop;
DI
TH
Voltage = 1.2V to 1.6V
Transconductance Amplifier g
m
I
Q
UVLO
Input DC Supply Current
Normal Mode
Shutdown
Undervoltage Lockout on INTV
CC
UVLO Hysteresis
Feedback Overvoltage Lockout
I
SENSE
V
RUN1,2,3
Sense Pin Current
Soft-Start Charge Current
RUN Pin ON Threshold
RUN Pin Hysteresis
Maximum Current Sense Threshold
I
TH1,2,3
= 1.85V, V
SENSE1,2,3
= 3.3V, I
LIM
= 0V
I
TH1,2,3
= 1.85V, V
SENSE1,2,3
= 3.3V, I
LIM
= 0V (H-, MP-
Grade)
I
TH1,2,3
= 1.85V, V
SENSE1,2,3
= 3.3V, I
LIM
= Float
I
TH1,2,3
= 1.85V, V
SENSE1,2,3
= 3.3V, I
LIM
= Float (H-, MP-
Grade)
I
TH1,2,3
= 1.85V, V
SENSE1,2,3
= 3.3V, I
LIM
= INTV
CC
I
TH1,2,3
= 1.85V, V
SENSE1,2,3
= 3.3V, I
LIM
= INTV
CC
(H-,
MP-Grade)
Maximum Duty Factor
TG Driver Pull-Up On-Resistance
TG Driver Pull-Down On-Resistance
BG Driver Pull-Up On-Resistance
BG Driver Pull-Down On-Resistance
TG Transition Time:
Rise Time
Fall Time
BG Transition Time:
Rise Time
Fall Time
In Dropout
TG High
TG Low
BG High
BG Low
(Note 6)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
(Note 6)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
l
l
l
l
l
l
l
l
The
l
denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 3), V
IN
= 15V, V
RUN1,2,3
= 5V, unless otherwise noted.
CONDITIONS
MIN
0.8
0.8
0.790
0.792
0.794
0.800
0.800
0.800
–10
0.002
TYP
MAX
5.5
13.5
0.810
0.808
0.806
–50
0.02
UNITS
V
V
V
V
V
nA
%/V
Feedback Current
Reference Voltage Line Regulation
Output Voltage Load Regulation
l
l
0.01
–0.01
2.2
4.1
42
3.35
0.5
0.1
–0.1
%
%
mmho
mA
µA
V
V
I
TH1,2,3
= 1.2V, Sink/Source 5µA (Note 4)
(Note 5)
V
IN
= 15V
V
RUN1,2,3
= 0V
V
INTVCC
Ramping Down
Measured at V
FB1,2,3
(H-Grade, MP-Grade)
Measured at V
FB1,2,3
V
SENSE
= 3.3V
V
TK/SS1,2,3
= 0V
V
RUN1
, V
RUN2
, V
RUN3
Rising
l
l
l
70
0.84
0.84
0.9
1.1
22
21
42
41
65
64
97
0.86
0.86
±1
1.3
1.2
80
30
30
50
50
75
75
98
2.6
1.5
2.4
1.1
25
25
25
25
30
0.89
0.88
±2
1.7
1.35
38
39
58
59
85
86
V
V
µA
µA
V
mV
mV
mV
mV
mV
mV
mV
%
Ω
Ω
Ω
Ω
ns
ns
ns
ns
ns
3853fc
Top Gate Off to Bottom Gate On Delay (Note 6)
Synchronous Switch-On Delay Time C
LOAD
= 3300pF Each Driver
For more information
www.linear.com/LTC3853
3
LTC3853
ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
The
l
denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 3), V
IN
= 15V, V
RUN1,2,3
= 5V, unless otherwise noted.
CONDITIONS
MIN
TYP
30
90
4.8
l
MAX
UNITS
ns
ns
Bottom Gate Off to Top Gate On Delay (Note 6)
Top Switch-On Delay Time
C
LOAD
= 3300pF Each Driver
t
ON(MIN)
V
INTVCC
V
EXTVCC
Minimum On-Time
Internal V
CC
Voltage
INTV
CC
Load Regulation
EXTV
CC
Switchover Voltage
EXTV
CC
Voltage Drop
EXTV
CC
Hysteresis
Oscillator and Phase-Locked Loop
Nominal Frequency
Lowest Frequency
Highest Frequency
Channel 2-Channel 1 Phase
Channel 3-Channel 2 Phase
Channel 1-Channel 3 Phase
Channel 2-Channel 1 Phase
Channel 3-Channel 2 Phase
Channel 1-Channel 3 Phase
MODE/PLLIN Input Resistance
I
FREQ
PGOOD Outputs
PGOOD Voltage Low
I
PGOOD
PGOOD Leakage Current
PGOOD Trip Level
I
PGOOD
= 2mA
V
PGOOD
= 5V
V
FB
with Respect to Set Regulated Voltage
V
FB
Ramping Negative
V
FB
Ramping Positive
–5
5
Phase Detector Output Current
Sinking Capability
Sourcing Capability
f
MODE
< f
OSC
f
MODE
> f
OSC
V
FB2
Tied to V
IN
Through 200kΩ
V
FREQ
= 1.2V
V
FREQ
= 0V
V
FREQ
≥ 2.4V
450
210
670
(Note 7)
7V < V
IN
< 24V
I
CC
= 0mA to 50mA
EXTV
CC
Ramping Positive
I
CC
= 20mA, V
EXTVCC
= 5V
4.5
INTV
CC
Linear Regulator
5
0.5
4.7
30
200
500
250
750
120
120
120
180
60
120
250
–13
13
0.1
5.2
2
75
V
%
V
mV
mV
550
290
830
kHz
kHz
kHz
Deg
Deg
Deg
Deg
Deg
Deg
kΩ
µA
µA
0.3
±2
V
µA
%
%
– 7.5
7.5
–10
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 junction temperature, T
J
, is calculated from the ambient
temperature T
A
and power dissipation P
D
according to the following
formulas:
LTC3853UJ: T
J
= T
A
+ (P
D
• 33°C/W)
Note 3:
The LTC3853 is tested under pulsed load conditions such that
T
J
≈
T
A
.
The LTC3853E 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
LTC3853I is guaranteed over the –40°C to 125°C operating junction
temperature range. The LTC3853H is guaranteed over the –40°C to 150°C
operating junction temperature range and the LTC3853MP is tested and
guaranteed over the –55°C to 150°C operating junction temperature range.
High junction temperatures degrade operating lifetimes; operating lifetime
is derated for junction temperatures greater than 125°C. The maximum
ambient temperature consistent with these specifications is determined by
specific operating conditions in conjunction with board layout, the rated
package thermal resistance and other environmental factors.
Note 4:
The LTC3853 is tested in a feedback loop that servos V
ITH1,2,3
to a
specified voltage and measures the resultant V
FB1,2,3
.
Note 5:
Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See the Applications Information
section.
Note 6:
Rise and fall times are measured using 10% and 90% levels.
Delay times are measured using 50% levels.
Note 7:
The minimum on-time condition is specified for an inductor
peak-to-peak ripple current ≥40% of I
MAX
(see Minimum On-Time
Considerations in the Applications Information section).
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