VBIAS ........................................................ –0.3V to 40V
BOOST ........................................................–0.3V to 71V
SW ............................................................. –0.3V 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
SENSE
+
, SENSE
–
........................................ –0.3V to 40V
SENSE
+
– SENSE
–
..................................... –0.3V to 0.3V
SS, ITH, FREQ, VFB............................... –0.3V to INTV
CC
Operating Junction Temperature Range...–40°C to 125°C
Storage Temperature Range .................. –65°C to 125°C
Lead Temperature (Soldering, 10 sec)
MSE Package Only ............................................ 300°C
pin conFiguraTion
TOP VIEW
VFB
SENSE
+
SENSE
–
ITH
SS
PLLIN/MODE
FREQ
RUN
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
PGOOD
SW
TG
BOOST
VBIAS
INTV
CC
BG
GND
SW 1
PGOOD 2
VFB 3
SENSE
+
16 15 14 13
12 BG
17
GND
11 GND
10 RUN
9
5
SENSE
–
6
ITH
7
SS
8
PLLIN/
MODE
FREQ
17
GND
4
MSE PACKAGE
16-LEAD PLASTIC MSOP
T
JMAX
= 125°C,
θ
JA
= 40°C/W,
θ
JC
= 10°C/W
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
UD PACKAGE
16-LEAD (3mm
×
3mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 68°C/W,
θ
JC
= 4.2°C/W
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
orDer inForMaTion
LEAD FREE FINISH
LTC3786EMSE#PBF
LTC3786IMSE#PBF
LTC3786EUD#PBF
LTC3786IUD#PBF
TAPE AND REEL
LTC3786EMSE#TRPBF
LTC3786IMSE#TRPBF
LTC3786EUD#TRPBF
LTC3786IUD#TRPBF
PART MARKING*
3786
3786
LFXW
LFXW
PACKAGE DESCRIPTION
16-Lead Plastic MSOP
16-Lead Plastic MSOP
16-Lead (3mm
×
3mm) Plastic QFN
16-Lead (3mm
×
3mm) Plastic QFN
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°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/
INTV
CC
TOP VIEW
BOOST
VBIAS
TG
3786fa
2
LTC3786
elecTrical characTerisTics
SYMBOL
VBIAS
V
FB
I
FB
V
REFLNREG
V
LOADREG
PARAMETER
Chip Bias Voltage Operating Range
Regulated Feedback Voltage
Feedback Current
Reference Line Voltage Regulation
Output Voltage Load Regulation
I
TH
= 1.2V (Note 4)
(Note 4)
V
BIAS
= 6V to 38V
(Note 4)
Measured in Servo Loop;
∆I
TH
Voltage = 1.2V to 0.7V
Measured in Servo Loop;
∆I
TH
Voltage = 1.2V to 2V
I
TH
= 1.2V
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. V
BIAS
= 12V, unless otherwise noted (Note 2).
CONDITIONS
MIN
4.5
1.188
1.200
±5
0.002
0.01
–0.01
2
0.8
55
8
l
l
l
TYP
MAX
38
1.212
±50
0.02
0.1
–0.1
UNITS
V
V
nA
%/V
%
%
mmho
mA
µA
µA
V
V
V
mV
µA
µA
Main Control Loop
g
m
I
Q
Error Amplifier Transconductance
Input DC Supply Current
(Note 5)
Pulse-Skipping or Forced Continuous Mode
RUN = 5V; V
FB
= 1.25V (No Load)
Sleep Mode
RUN = 5V; V
FB
= 1.25V (No Load)
Shutdown
RUN = 0V
INTV
CC
Undervoltage Lockout Thresholds
RUN Pin On Threshold
RUN Pin Hysteresis
RUN Pin Hysteresis Current
RUN Pin Current
Soft-Start Charge Current
Maximum Current Sense Threshold
SENSE Pins Common Mode Range (BOOST
Converter Input Supply Voltage V
IN
)
SENSE
+
Pin Current
SENSE
–
Pin Current
Top Gate Rise Time
Top Gate Fall Time
Bottom Gate Rise Time
Bottom Gate Fall Time
Top Gate Pull-Up Resistance
Top Gate Pull-Down Resistance
Bottom Gate Pull-Up Resistance
Bottom Gate Pull-Down Resistance
Top Gate Off to Bottom Gate On Switch-On
Delay Time
Bottom Gate Off to Top Gate On Switch-On
Delay Time
Maximum BG Duty Factor
Minimum BG On-Time
(Note 7)
C
LOAD
= 3300pF (Each Driver)
C
LOAD
= 3300pF (Each Driver)
V
FB
= 1.1V
V
FB
= 1.1V
C
LOAD
= 3300pF (Note 6)
C
LOAD
= 3300pF (Note 6)
C
LOAD
= 3300pF (Note 6)
C
LOAD
= 3300pF (Note 6)
V
RUN
> 1.28V
V
RUN
< 1.28V
V
SS
= 0V
V
FB
= 1.1V
l
80
20
4.3
1.38
UVLO
V
RUN
V
RUNHYS
I
RUNHYS
I
RUN
I
SS
V
SENSE(MAX)
V
SENSE(CM)
I
SENSE+
I
SENSE–
t
r(TG)
t
f(TG)
t
r(BG)
t
f(BG)
R
UP(TG)
R
DN(TG)
R
UP(BG)
R
DN(BG)
t
D(TG/BG)
t
D(BG/TG)
DF
MAXBG
t
ON(MIN)
V
INTVCC
Ramping Up
V
INTVCC
Ramping Down
V
RUN
Rising
3.6
1.18
4.1
3.8
1.28
100
4.5
0.5
7
68
2.5
10
75
13
82
38
µA
mV
V
µA
µA
ns
ns
ns
ns
Ω
Ω
Ω
Ω
ns
ns
%
ns
200
20
20
20
20
1.2
1.2
1.2
1.2
80
80
96
110
300
±1
3786fa
3
LTC3786
elecTrical characTerisTics
SYMBOL
V
INTVCC(VIN)
V
LDO
INT
f
PROG
f
LOW
f
HIGH
f
SYNC
PGOOD Output
V
PGL
I
PGOOD
V
PG
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level
I
PGOOD
= 2mA
V
PGOOD
= 5V
V
FB
with Respect to Set Regulated Voltage
V
FB
Ramping Negative
Hysteresis
V
FB
Ramping Positive
Hysteresis
PGOOD Going High to Low
V
SW
= 12V; V
BOOST
– V
SW
= 4.5V;
FREQ = 0V, Forced Continuous or
Pulse-Skipping Mode
–12
8
–10
2.5
10
2.5
25
85
0.2
0.4
±1
–8
12
V
µA
%
%
%
%
µs
µA
PARAMETER
Internal V
CC
Voltage
INTV
CC
Load Regulation
Programmable Frequency
INTV
CC
Linear Regulator
6V < VBIAS < 38V
I
CC
= 0mA to 50mA
R
FREQ
= 25k
R
FREQ
= 60k
R
FREQ
= 100k
V
FREQ
= 0V
V
FREQ
= INTV
CC
PLLIN/MODE = External Clock
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
BIAS
= 12V, unless otherwise noted (Note 2).
CONDITIONS
MIN
5.2
TYP
5.4
0.5
105
400
760
350
535
MAX
5.6
2
UNITS
V
%
kHz
kHz
kHz
kHz
kHz
kHz
Oscillator and Phase-Locked Loop
335
320
485
75
465
380
585
850
Lowest Fixed Frequency
Highest Fixed Frequency
Synchronizable Frequency
t
PGOOD(DELAY)
I
BOOST
PGOOD Delay
BOOST Charge Pump Available
Output Current
BOOST Charge Pump
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 LTC3786 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3786E is guaranteed to meet 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
LTC3786I is guaranteed over the –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
in °C) is calculated from the ambient temperature (T
A
in °C) and power
dissipation (P
D
in Watts) according to the formula:
T
J
= T
A
+ (P
D
•
θ
JA
)
where
θ
JA
= 68°C for the QFN package and
θ
JA
= 40°C for the MSOP
package.
Note 3:
This IC includes overtemperature 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:
The LTC3786 is tested in a feedback loop that servos V
FB
to the
output of the error amplifier while maintaining I
TH
at the midpoint of the
current limit range.
Note 5:
Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency.
Note 6:
Rise and fall times are measured using 10% and 90% levels. Delay
times are measured using 50% levels.
Note 7:
see Minimum On-Time Considerations in the Applications
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