Peak Output Current ................................100mA
Operating Junction Temperature Range
(Note 2)..................................................–40°C to 125°C
Junction Temperature (Note 3) ............................. 125°C
Storage Temperature Range...................–65°C to 150°C
Lead Temperature (Soldering, 10 sec)
GN Package ...................................................... 300°C
PIN CONFIGURATION
TOP VIEW
MODE/PLLIN
SENSE1
+
TOP VIEW
RUN1
SW1
TG1
1
2
3
4
5
6
7
8
9
28 FREQ
27 MODE/PLLIN
26 SW1
25 TG1
24 BOOST1
23 BG1
22 V
IN
21 INTV
CC
20 BG2
19 PGND
18 BOOST2
17 TG2
16 SW2
15 PGOOD
RUN1
FREQ
SENSE1
+
SENSE1
–
V
FB1
TK/SS1
I
TH1
SGND
I
TH2
TK/SS2
28 27 26 25 24 23
SENSE1
–
1
TK/SS1 2
I
TH1
3
V
FB1
4
V
FB2
5
I
TH2
6
TK/SS2 7
SENSE2
–
8
9 10 11 12 13 14
RUN2
SENSE2
+
EXTV
CC
PGOOD
SW2
I
LIM
SGND
29
22 BOOST1
21 BG1
20 V
IN
19 INTV
CC
18 BG2
17 PGND
16 BOOST2
15 TG2
V
FB2
10
SENSE2
–
11
SENSE2
+
12
RUN2 13
EXTV
CC
14
UFD PACKAGE
28-LEAD (4mm
×
5mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 34°C/W,
EXPOSED PAD (PIN 29) IS SGND, MUST BE SOLDERED TO PCB
GN PACKAGE
28-LEAD PLASTIC SSOP
T
JMAX
= 125°C,
θ
JA
= 80°C/W
ORDER INFORMATION
LEAD FREE FINISH
LTC3869EUFD#PBF
LTC3869IUFD#PBF
LTC3869IGN-2#PBF
TAPE AND REEL
LTC3869EUFD#TRPBF
LTC3869IUFD#TRPBF
LTC3869IGN-2#TRPBF
PART MARKING*
3869
3869
LTC3869GN-2
PACKAGE DESCRIPTION
28-Lead (4mm
×
5mm) Plastic QFN
28-Lead (4mm
×
5mm) Plastic QFN
28-Lead Narrow Plastic SSOP
TEMPERATURE RANGE
–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/
3869f
2
LTC3869/LTC3869-2
ELECTRICAL CHARACTERISTICS
SYMBOL
V
IN
V
OUT
V
FB1,2
I
FB1,2
V
REFLNREG
V
LOADREG
g
m1,2
I
Q
DF
MAX
UVLO
UVLO
HYS
V
OVL
I
SENSE
I
TK/SS1,2
V
RUN1,2
PARAMETER
Input Voltage Range
Output Voltage Range
Regulated Feedback Voltage
(Notes 2, 4)
Feedback Current
Reference Voltage Line Regulation
Output Voltage Load Regulation
I
TH1,2
Voltage = 1.2V, 0°C to 85°C
I
TH1,2
Voltage = 1.2V, –40°C to 125°C
(Note 4)
V
IN
= 4.0V to 38V (Note 4)
(Note 4)
Measured in Servo Loop; ∆I
TH
Voltage = 1.2V to 0.7V
l
Measured in Servo Loop; ∆I
TH
Voltage = 1.2V to 1.6V
l
I
TH1,2
= 1.2V; Sink/Source 5µA; (Note 4)
(Note 5)
V
IN
= 15V
V
RUN1,2
= 0V
In Dropout
V
INTVCC
Ramping Down
Measured at V
FB1,2
(Each Channel); V
SENSE1,2
= 3.3V
V
TK/SS1,2
= 0V
V
RUN1
, V
RUN2
Rising
V
FB1,2
= 0.5V, V
SENSE1,2
= 3.3V, I
LIM
= 0V
V
FB1,2
= 0.5V, V
SENSE1,2
= 3.3V, I
LIM
= Float
V
FB1,2
= 0.5V, V
SENSE1,2
= 3.3V, I
LIM
= INTV
CC
V
FB1,2
= 0.5V, V
SENSE1,2
= 3.3V, I
LIM
= 0V
V
FB1,2
= 0.5V, V
SENSE1,2
= 3.3V, I
LIM
= Float
V
FB1,2
= 0.5V, V
SENSE1,2
= 3.3V, I
LIM
= INTV
CC
V
FB1,2
= 0.5V, V
SENSE1,2
= 3.3V, LTC3869IGN-2
I
LIM
= Float
(Note 8)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
(Note 8)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
25
25
25
25
30
30
90
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 2). V
IN
= 15V, V
RUN1,2
= 5V unless otherwise noted.
CONDITIONS
MIN
4
0.6
0.5955
0.5940
0.600
0.600
–15
0.002
0.01
–0.01
2
3
30
94
3.0
0.64
1.0
1.1
25
45
68
23
43
68
40
95
3.2
0.6
l
l
l
l
TYP
MAX
38
12.5
0.6045
0.6060
–50
0.01
0.1
–0.1
UNITS
V
V
V
V
nA
%/V
%
%
mmho
mA
µA
%
V
V
V
µA
µA
V
mV
mV
mV
mV
mV
mV
mV
mV
mV
Main Control Loops
Transconductance Amplifier g
m
Input DC Supply Current
Normal Mode
Shutdown
Maximum Duty Factor
Undervoltage Lockout
UVLO Hysteresis
Feedback Overvoltage Lockout
Sense Pins Bias Current
Soft-Start Charge Current
RUN Pin On Threshold
50
3.4
0.68
±2
1.5
1.35
35
55
82
37
57
82
60
2
0.66
±1
1.25
1.22
80
30
50
75
30
50
75
50
V
RUN1,2(HYS)
RUN Pin On Hysteresis
V
SENSE(MAX)
Maximum Current Sense Threshold,
0°C to 85°C (Note 2)
Maximum Current Sense Threshold,
–40°C to 125°C (Note 2)
l
l
l
l
l
l
l
V
MISMATCH
TG1, 2 t
r
TG1, 2 t
f
BG1, 2 t
r
BG1, 2 t
f
TG/BG t
1D
BG/TG t
2D
t
ON(MIN)
Channel to Channel Current Sense
Mismatch Voltage of V
SENSE(MAX)
TG Transition Time:
Rise Time
Fall Time
BG Transition Time:
Rise Time
Fall Time
ns
ns
ns
ns
ns
ns
ns
Top Gate Off to Bottom Gate On Delay C
LOAD
= 3300pF Each Driver (Note 6)
Synchronous Switch-On Delay Time
Bottom Gate Off to Top Gate On Delay C
LOAD
= 3300pF Each Driver (Note 6)
Top Switch-On Delay Time
Minimum On-Time
(Note 7)
3869f
3
LTC3869/LTC3869-2
ELECTRICAL CHARACTERISTICS
SYMBOL
V
INTVCC
V
LDO
INT
V
EXTVCC
V
LDOHYS
V
LDO
EXT
V
PGL
I
PGOOD
V
PG
PARAMETER
Internal V
CC
Voltage
INTV
CC
Load Regulation
EXTV
CC
Switchover Voltage
EXTV
CC
Hysteresis
EXTV
CC
Voltage Drop
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level
I
CC
= 20mA, V
EXTVCC
= 5V
I
PGOOD
= 2mA
V
PGOOD
= 5V
V
FB
with Respect to Set Output Voltage
V
FB
Ramping Negative
V
FB
Ramping Positive
V
FREQ
= 1.2V
V
FREQ
= 0V
V
FREQ
≥ 2.4V
450
210
700
9
TG High
TG Low
BG High
BG Low
–10
10
500
250
780
250
10
2.6
1.5
2.4
1.1
Note 3:
T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formulas:
LTC3869UFD: T
J
= T
A
+ (P
D
• 34°C/W)
LTC3869GN-2: T
J
= T
A
+ (P
D
• 80°C/W)
Note 4:
The LTC3869 is tested in a feedback loop that servos V
ITH1,2
to a
specified voltage and measures the resultant V
FB1,2
.
Note 5:
Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications Information.
Note 6:
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).
Note 8:
Guaranteed by design.
11
550
290
850
INTV
CC
Linear Regulator
6V < V
IN
< 38V
I
CC
= 0mA to 20mA
EXTV
CC
Ramping Positive
l
The
l
denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 15V, V
RUN1,2
= 5V unless otherwise noted.
CONDITIONS
MIN
4.8
4.5
TYP
5
0.5
4.7
200
50
0.1
100
0.3
±2
MAX
5.2
2
UNITS
V
%
V
mV
mV
V
µA
%
%
kHz
kHz
kHz
kΩ
µA
Ω
Ω
Ω
Ω
PGOOD Output
Oscillator and Phase-Locked Loop
f
NOM
f
LOW
f
HIGH
I
FREQ
TG R
UP
TG R
DOWN
BG R
UP
BG R
DOWN
Nominal Frequency
Lowest Frequency
Highest Frequency
Frequency Setting Current
TG Pull-Up R
DS(ON)
TG Pull-Down R
DS(ON)
BG Pull-Up R
DS(ON)
BG Pull-Down R
DS(ON)
R
MODE/PLLIN
MODE/PLLIN Input Resistance
On Chip Driver
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 LTC3869 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3869E is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 125°C operating
junction temperature range are assured by design, characterization
and correlation with statistical process controls. The LTC3869I is
guaranteed to meet performance specifications over the full –40°C to
125°C operating junction temperature range. The maximum ambient
temperature consistent with these specifications is determined by specific
operating conditions in conjunction with board layout, the package thermal
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