when used in diode-OR and high current diode applica-
tions. The LTC4358 reduces power consumption, heat
dissipation, and PC board area.
The LTC4358 easily ORs power supplies together to in-
crease total system reliability. In diode-OR applications,
the LTC4358 regulates the forward voltage drop across
the internal MOSFET to ensure smooth current transfer
from one path to the other without oscillation. If the power
source fails or is shorted, a fast turnoff minimizes reverse
current transients.
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Replaces a Power Schottky Diode
Internal 20mΩ N-Channel MOSFET
0.5μs Turn-Off Time Limits Peak Fault Current
Operating Voltage Range: 9V to 26.5V
Smooth Switchover without Oscillation
No Reverse DC Current
Available in 14-Pin (4mm
×
3mm) DFN and
16-Lead TSSOP Packages
APPLICATIONS
n
n
n
n
N+1 Redundant Power Supplies
High Availability Systems
Telecom Infrastructure
Automotive Systems
TYPICAL APPLICATION
12V, 5A Diode-OR
3.0
V
INA
= 12V
IN
DRAIN
POWER DISSIPATION (W)
OUT
LTC4358
GND
V
DD
V
OUT
TO
5A LOAD
2.5
DIODE (B530C)
2.0
1.5
POWER SAVED
1.0
0.5
V
INB
= 12V
IN
DRAIN
0
OUT
LTC4358
GND
4358 TA01
Power Dissipation vs Load Current
FET (LTC4358)
0
2
4
CURRENT (A)
6
8
4358 TA01b
V
DD
4358fa
1
LTC4358
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
Supply Voltages
IN, OUT, V
DD
, DRAIN Voltage ................. –0.3V to 28V
Output Voltage
GATE (Note 3) .......................... V
IN
– 0.2V to V
IN
+ 6V
Operating Ambient Temperature Range
LTC4358C ................................................ 0°C to 70°C
LTC4358I.............................................. –40°C to 85°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
FE Package ....................................................... 300°C
PIN CONFIGURATION
TOP VIEW
TOP VIEW
IN
IN
IN
IN
GATE
NC
GND
1
2
3
4
5
6
7
15
DRAIN
14 IN
13 IN
12 IN
11 IN
10 NC
9 OUT
8 V
DD
IN
IN
IN
IN
NC
GATE
NC
GND
DE PACKAGE
14-LEAD (4mm 3mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JC
= 4°C/W,
θ
JA
= 43°C/W
1
2
3
4
5
6
7
8
17
DRAIN
16 IN
15 IN
14 IN
13 IN
12 IN
11 NC
10 OUT
9
V
DD
FE PACKAGE
16-LEAD PLASTIC TSSOP
T
JMAX
= 125°C,
θ
JC
= 10°C/W,
θ
JA
= 38°C/W
ORDER INFORMATION
LEAD FREE FINISH
LTC4358CDE#PBF
LTC4358IDE#PBF
LTC4358CFE#PBF
LTC4358IFE#PBF
TAPE AND REEL
LTC4358CDE#TRPBF
LTC4358IDE#TRPBF
LTC4358CFE#TRPBF
LTC4358IFE#TRPBF
PART MARKING*
4358
4358
4358FE
4358FE
PACKAGE DESCRIPTION
14-Lead (4mm × 3mm) Plastic DFN
14-Lead (4mm × 3mm) Plastic DFN
16-Lead Plastic TSSOP
16-Lead Plastic TSSOP
TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *Temperature grades are 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/
4358fa
2
LTC4358
ELECTRICAL CHARACTERISTICS
SYMBOL
V
DD
I
DD
I
IN
I
OUT
I
DRAIN
ΔV
GATE
I
GATE(UP)
I
GATE(DOWN)
t
ON
t
OFF
ΔV
SD
ΔV
SD
R
DS(ON)
PARAMETER
Operating Supply Range
Operating Supply Current
IN Pin Current
OUT Pin Current
DRAIN Pin Current
N-Channel Gate Drive (V
GATE
– V
IN
)
N-Channel Gate Pull Up Current
N-Channel Gate Pull Down
Current in Fault Condition
Turn-On Time
Turn-Off Time
Source-Drain Regulation Voltage
(V
IN
– V
OUT
)
Body Diode Forward Voltage Drop
Internal N-Channel MOSFET On
Resistance
V
IN
= V
OUT
± 1V, No Load
V
IN
= V
OUT
± 1V, No Load
V
IN
= 0V, V
OUT
= V
DD
= V
DRAIN
= 26.5V
V
DD,
V
OUT
= 9V to 26.5V
V
GATE
= V
IN,
V
IN
– V
OUT
= 0.1V
V
GATE
= V
IN
+ 5V
–
V
IN
– V
OUT
= –1V
–
| 0.1V, V
DRAIN
= V
IN
,
V
OUT
= V
DD,
V
GATE
– V
IN
> 4.5V
–
V
IN
– V
OUT
= 55mV |
–
–1V, V
DRAIN
= V
IN
,
V
OUT
= V
DD,
V
GATE
– V
IN
< 1V
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
OUT
= V
DD
, V
DD
= 9V to 26.5V, unless otherwise noted.
CONDITIONS
l
l
l
l
l
l
l
l
l
l
l
l
l
MIN
9
150
TYP
MAX
26.5
0.6
UNITS
V
mA
μA
μA
μA
μA
V
μA
A
350
80
450
160
5
150
4.5
–14
1
–20
2
200
300
10
0.6
25
0.8
20
15
–26
500
500
55
1
40
μs
ns
mV
V
mΩ
1mA < I
IN
< 100mA
I
IN
= 5A, MOSFET Off
I
IN
= 5A
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 pins are positive, all voltages are referenced to
GND unless otherwise specified.
Note 3:
An internal clamp limits the GATE pin to a minimum of 6V above
IN. Driving this pin to voltages beyond this clamp may damage the device.
4358fa
3
LTC4358
TYPICAL PERFORMANCE CHARACTERISTICS
V
DD
Current (I
DD
vs V
DD
)
500
V
IN
= V
OUT
= V
DD
400
300
I
OUT
(μA)
400
IN Current (I
IN
vs V
IN
)
100
V
IN
= V
OUT
= V
DD
80
OUT Current (I
OUT
vs V
OUT
)
V
IN
= V
OUT
= V
DD
I
DD
(μA)
I
IN
(μA)
300
60
200
200
100
100
40
20
0
0
0
10
V
DD
(V)
4358 G01
20
30
0
10
V
IN
(V)
20
30
4358 G02
0
0
10
V
OUT
(V)
20
30
4358 G03
MOSFET R
DS(ON)
vs Temperature
30
I
IN
= 5A
25
V
OUT
= V
DD
= 9V
R
DS(ON)
(mΩ)
20
15
V
OUT
= V
DD
= 26.5V
10
100
5
0
-50
0
t
PD
(ns)
300
400
FET Turn-Off Time
vs Initial Overdrive
2000
FET Turn-Off Time
vs Final Overdrive
V
IN
= 12V
V
SD
= 55mV
1500
V
FINAL
t
PD
(ns)
-1V
200
V
IN
= 12V
V
SD
= V
INITIAL
1000
500
-25
0
25
50
75
100
125
0
0
0.2
0.4
0.6
0.8
1
4358 G05
0
-0.2
-0.4
-0.6
-0.8
-1
4358 G06
TEMPERATURE (˚C)
4358 G04
V
INITIAL
(V)
V
FINAL
(V)
4358fa
4
LTC4358
PIN FUNCTIONS
(DE/FE PACKAGES)
DRAIN:
The exposed pad is the drain of the internal
N-channel MOSFET. This pin must be connected to OUT
(Pin 9/Pin 10).
GATE:
Gate Drive Output. If reverse current flows, a fast
pulldown circuit quickly connects the GATE pin to the IN
pin, turning off the MOSFET. Leave open if unused.
GND:
Device Ground.
IN:
Input Voltage and Fast Pulldown Return. IN is the
anode of the ideal diode. The voltage sensed at this pin is
used to control the source-drain voltage drop across the
internal MOSFET. If reverse current starts to flow, a fast
pulldown circuit quickly turns off the internal MOSFET. The
fast pulldown current is returned through this pin.
NC:
No Connection. Not internally connected.
OUT:
Output Voltage. The OUT pin is the cathode of the ideal
diode and the common output when multiple LTC4358s
are configured as an ideal diode-OR. The voltage sensed
at this pin is used to control the source-drain voltage drop
across the MOSFET. Connect this pin to the drain of the
internal N-channel MOSFET (Pin 15/Pin 17).
V
DD
:
Positive Supply Input. The LTC4358 is powered from
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