Voltage................................................ 2.7V to –0.3V
RUN, PGOOD Voltage ................................. 6V to –0.3V
Operating Junction Temperature Range
(Notes 2, 3) ............................................ –40°C to 125°C
Storage Temperature Range................... –65°C to 125°C
INTV
CC
Peak Output Current ................................100mA
Lead Temperature (Soldering, 10 sec.)
GN Package...................................................... 300°C
pin conFiguraTion
TOP VIEW
SENSE
+
V
FB
SS
SENSE
+
SENSE
–
TOP VIEW
PGOOD
28 PGOOD
27 SW1
26 TG1
25 BOOST1
24 PGND
23 BG1
22 V
IN
21 INTV
CC
20 EXTV
CC
19 BG2
18 BOOST2
17 TG2
16 SW2
15 TRIM
SENSE
–
1
I
TH
2
SGND 3
MODE/PLLIN 4
FREQ 5
RUN 6
V
INSNS
7
V
OUTSNS
8
9 10 11 12 13 14
I
OSENSE+
I
LIM
–
1
2
3
4
5
6
7
8
9
SW1
SW2
28 27 26 25 24 23
22 BOOST1
21 PGND
20 BG1
29
SGND
19 V
IN
18 INTV
CC
17 EXTV
CC
16 BG2
15 BOOST2
TRIM
TG2
I
TH
SGND
MODE/PLLIN
FREQ
RUN
V
INSNS
10
V
OUTSNS
11
I
LIM
12
I
OSENSE+
13
I
OSENSE
–
14
GN PACKAGE
28-LEAD NARROW PLASTIC SSOP
T
JMAX
= 125°C,
θ
JA
= 80°C/W
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
orDer inForMaTion
LEAD FREE FINISH
LTC3789EGN#PBF
LTC3789IGN#PBF
LTC3789EUFD#PBF
LTC3789IUFD#PBF
TAPE AND REEL
LTC3789EGN#TRPBF
LTC3789IGN#TRPBF
LTC3789EUFD#TRPBF
LTC3789IUFD#TRPBF
PART MARKING*
LTC3789
LTC3789
3789
3789
PACKAGE DESCRIPTION
28-Lead Narrow Plastic SSOP
28-Lead Narrow Plastic SSOP
28-Lead (4mm × 5mm) Plastic QFN
28-Lead (4mm × 5mm) 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.
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/
3789f
2
I
OSENSE
TG1
V
FB
SS
LTC3789
elecTrical characTerisTics
SYMBOL
V
IN
V
OUT
V
FB
I
FB
V
REFLNREG
V
LOADREG
g
m
I
Q
UVLO
UVLO Hyst
I
SENSE+
I
SENSE–
I
IOSENSE+
I
IOSENSE–
I
SS
V
RUN(ON)
V
RUN(HYS)
I
RUN
I
RUN(HYS)
V
SENSE(MAX)
V
SENSE(IAVG)
R
DSPFET(ON)
R
DSNFET(ON)
TG t
r
TG t
f
BG t
r
BG t
f
TG/BG t
1D
BG/TG t
1D
DF
MAX,BOOST
D
ON(MIN,BOOST)
D
ON(MIN,BUCK)
PARAMETER
Input Supply Voltage
Output Voltage
Regulated Feedback Voltage
Feedback Current
Reference Voltage Line Regulation
Output Voltage Load Regulation
I
TH
Voltage = 1.2V (Note 4), T
A
= –40°C to 85°C
I
TH
= 1.2V, T
A
= 125°C, T
A
= –40°C to 125°C
(Note 4)
V
IN
= 4V to 38V (Note 4)
(Note 4)
Measured in Servo Loop, ∆I
TH
Voltage = 1.4V to 2V
Measured in Servo Loop, ∆I
TH
Voltage = 2V to 2.6V
I
TH
= 1.2V, Sink/Source 5µA (Note 4)
(Note 5)
V
RUN
= 0V
INTV
CC
Ramping Down
V
SENSE–
= V
SENSE+
= 0V
V
IOSENSE–
= V
IOSENSE+
= 10V
V
SS
= 0V
V
RUN
Rising
2
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 2). V
IN
= 15V, V
RUN
= 5V, unless otherwise noted.
CONDITIONS
MIN
4
0.8
0.792
0.788
0.800
0.800
–15
0.002
0.01
–0.01
1.5
3
40
3.4
0.4
0.2
10
3
1.22
150
1.2
5
l
l
TYP
MAX
38
38
0.808
0.812
–50
0.02
0.1
–0.1
UNITS
V
V
V
V
nA
%/V
%
%
mmho
mA
µA
V
V
µA
µA
µA
V
mV
µA
µA
Transconductance Amplifier g
m
Input DC Supply Current
Normal Mode
Shutdown
Undervoltage Lockout
Undervoltage Hysteresis
SENSE Pins Current
I
OSENSE
Pins Current
Soft-Start Charge Current
RUN Pin On-Threshold
RUN Pin On-Hysteresis
RUN Pin Source Current
RUN Pin Hysteresis Current
60
3.6
±1
14
4
Maximum Current Sense Threshold
V
FB
= 0.7V
Buck Region
Boost Region
V
FB
= 0.7V
Maximum Input/Output Average
Current Sense Threshold
Driver Pull-Up On-Resistance
Driver Pull-Down On-Resistance
Top Gate Rise Time
Top Gate Fall Time
Bottom Gate Rise Time
Bottom Gate Fall Time
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
Maximum Duty Factor
Minimum Duty Factor for Main
Switch in Boost Operation
Minimum Duty Factor for Main
Switch in Buck Operation
C
LOAD
= 3300pF Each Driver (Note 6)
C
LOAD
= 3300pF Each Driver (Note 6)
% Switch C On
% Switch C On
% Switch B On
I
LIM
= 0V
I
LIM
Floating
I
LIM
= INTV
CC
60
110
47
90
130
90
140
50
100
145
2.6
1.5
25
25
25
25
60
110
165
53
106
160
mV
mV
mV
mV
mV
Ω
Ω
ns
ns
ns
ns
ns
60
90
9
9
ns
%
%
%
3789f
3
LTC3789
elecTrical characTerisTics
SYMBOL
V
INTVCCVIN
V
LDOVIN
V
INTVCCEXT
V
LDOEXT
V
EXTVCC
V
LDOHYS
f
NOM
f
LOW
f
HIGH
f
SYNC
R
MODE/PLLIN
I
FREQ
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 Output Voltage
V
FB
Ramping Negative
V
FB
Ramping Positive
–10
10
0.1
0.3
±1
V
µA
%
%
PARAMETER
Internal V
CC
Voltage
INTV
CC
Load Regulation
Internal V
CC
Voltage
INTV
CC
Load Regulation
EXTV
CC
Switchover Voltage
EXTV
CC
Hysteresis
Nominal Frequency
Low Fixed Frequency
High Fixed Frequency
Synchronizable Frequency
MODE/PLLIN Input Resistance
Frequency Setting Current
8
V
FREQ
= 1.2V, R
FREQ
= 1.22k
V
FREQ
= 0V
V
FREQ
= 2.4V
MODE/PLLIN = External Clock
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
RUN
= 5V, unless otherwise noted.
CONDITIONS
6.5V < V
IN
< 40V, V
EXTVCC
= 0V
I
CC
= 0mA to 20mA, V
EXTVCC
= 0V
6.5V < V
EXTVCC
< 14V
I
CC
= 0mA to 20mA, V
EXTVCC
= 12V
I
CC
= 0mA to 20mA, EXTV
CC
Ramping Positive
4.7
5.2
MIN
5.2
TYP
5.5
0.2
5.5
0.2
4.8
0.25
350
175
570
200
220
10
12
400
200
640
440
225
710
600
MAX
5.8
1.0
5.8
1.0
UNITS
V
%
V
%
V
V
kHz
kHz
kHz
kHz
kΩ
µA
INTV
CC
Linear Regulator
Oscillator and Phase-Locked Loop
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 LTC3789 is tested under pulse load conditions such that
T
J
≈
T
A
. The LTC3789E is guaranteed to meet performance specifications
from 0°C to 85°C operating 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 LTC3789I is guaranteed to meet performance specifications over the
full –40°C to 125°C operating junction temperature range.
Note 3:
T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
LTC3789GN: T
J
= T
A
+ (P
D
• 80°C/W)
LTC3789UFD: T
J
= T
A
+ (P
D
• 34°C/W)
Note 4:
The LTC3789 is tested in a feedback loop that servos V
ITH
to a
specified voltage and measures the resultant V
FB
.
Note 5:
Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See the Applications Information
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