LTC1154CN8#TRPBF [Linear]
IC BUF OR INV BASED MOSFET DRIVER, PDIP8, 0.300 INCH, LEAD FREE, PLASTIC, DIP-8, MOSFET Driver;型号: | LTC1154CN8#TRPBF |
厂家: | Linear |
描述: | IC BUF OR INV BASED MOSFET DRIVER, PDIP8, 0.300 INCH, LEAD FREE, PLASTIC, DIP-8, MOSFET Driver 驱动 光电二极管 接口集成电路 驱动器 |
文件: | 总18页 (文件大小:189K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
LTC1154
High Side Micropower
MOSFET Driver
FEATURES
DESCRIPTION
TheLTC®1154singlehighsidegatedriverallowsusinglow
costN-channelFETsforhighsideswitchingapplications.An
internal charge pump boosts the gate drive voltage above
thepositiverail, fullyenhancinganN-channelMOSswitch
withnoexternalcomponents. Micropoweroperation, with
8μA standby current and 85μA operating current, allows
use in virtually all systems with maximum efficiency.
n
Fully Enhances N-Channel Power MOSFETs
n
8μA I Standby Current
Q
n
85μA I ON Current
Q
n
No External Charge Pump Capacitors
n
4.5V to 18V Supply Range
Short-Circuit Protection
n
n
Thermal Shutdown via PTC Thermistor
n
Status Output Indicates Shutdown
Included on chip is programmable overcurrent sensing.
A time delay can be added to prevent false triggering on
high inrush current loads. An active high shutdown input
is also provided and interfaces directly to a standard PTC
thermistor for thermal shutdown. An open-drain output
is provided to report switch status to the μP. An active
low enable input is provided to control multiple switches
in banks.
n
Available in 8-Pin SOIC and PDIP Packages
APPLICATIONS
n
Laptop Computer Power Switching
n
SCSI Termination Power Switching
n
Cellular Telephone Power Management
Battery Charging and Management
High Side Industrial and Automotive Switching
Stepper Motor and DC Motor Control
n
n
The LTC1154 is available in both 8-pin DIP and 8-pin SOIC
packages.
n
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Ultralow Voltage Drop High Side Switch with
Short-Circuit Protection
Standby Supply Current
50
V
J
= 0V
= 25°C
IN
5V
45
40
35
30
25
20
15
10
5
T
51k
0.036Ω*
2.7A MAX
IN
V
S
0.1μF**
200k**
μP
EN
DS
G
LTC1154
STATUS
GND
IRLR024
SD
5V
LOAD
0
0
5
10
15
20
LTC1154 • TA01
ALL COMPONENTS SHOWN ARE SURFACE MOUNT.
* IMS026 INTERNATIONAL MANUFACTURING SERVICE, INC. (401) 683-9700
** NOT REQUIRED IF LOAD IS RESISTIVE OR INDUCTIVE.
SUPPLY VOLTAGE (V)
LTC1153 • TA02
1154fb
1
LTC1154
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Supply Voltage..........................................................22V
Operating Temperature
Input Voltage.......................(V + 0.3V) to (GND – 0.3V)
LTC1154C ................................................ 0°C to 70°C
LTC1154H .......................................... –40°C to 150°C
Storage Temperature Range....................–65°c to 150°C
Lead Temperature (Soldering, 10 sec.) ................. 300°C
S
Enable Input Voltage ...........(V + 0.3V) to (GND – 0.3V)
S
Gate Voltage.........................(V + 24V) to (GND – 0.3V)
S
Status Output Voltage ...............................................15V
Current (Any Pin)...................................................50mA
PIN CONFIGURATION
TOP VIEW
TOP VIEW
IN
ENABLE
STATUS
GND
1
2
3
4
8
7
6
5
V
IN
ENABLE
STATUS
GND
1
2
3
4
V
S
8
7
6
5
S
DRAIN SENSE
GATE
DRAIN SENSE
GATE
SHUTDOWN
SHUTDOWN
S8 PACKAGE
8-LEAD PLASTIC SOIC
= 100°C, θ = 150°C/W
N8 PACKAGE
8-LEAD PLASTIC DIP
= 100°C, θ = 130°C/W
T
JMAX
T
JA
JMAX
JA
ORDER INFORMATION
LEAD FREE FINISH
LTC1154CN8#PBF
LTC1154CS8#PBF
LTC1154HS8#PBF
LEAD BASED FINISH
LTC1154CN8
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
8-Lead Plastic DIP
TEMPERATURE RANGE
0°C to 70°C
LTC1154CN8#TRPBF
LTC1154CS8#TRPBF
LTC1154HS8#TRPBF
TAPE AND REEL
1154
8-Lead Plastic SIOC
8-Lead Plastic SIOC
PACKAGE DESCRIPTION
8-Lead Plastic DIP
0°C to 70°C
1154H
–40°C to 150°C
TEMPERATURE RANGE
0°C to 70°C
PART MARKING
LTC1154CN8#TR
LTC1154CS8#TR
LTC1154HS8#TR
LTC1154CS8
1154
8-Lead Plastic SIOC
8-Lead Plastic SIOC
0°C to 70°C
LTC1154HS8
1154H
–40°C to 150°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
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/
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = 4.5V to 18V, TA = 25°C, VEN = 0V, VSD = 0V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
18
UNITS
V
l
V
S
Supply Voltage
4.5
I
Quiescent Current OFF
Quiescent Current ON
Quiescent Current ON
Input High Voltage
V = 5V, V = 0V
8
20
μA
μA
μA
V
Q
S
IN
V = 5V, V = 5V
85
120
400
S
IN
V = 12V, V = 5V
180
S
IN
l
V
2
INH
1154fb
2
LTC1154
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = 4.5V to 18V, TA = 25°C, VEN = 0V, VSD = 0V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
0.8
1
UNITS
V
l
l
V
Input Low Voltage
INL
I
IN
Input Current
0V < V < V
μA
pF
V
IN
S
C
V
V
Input Capacitance
5
2.6
1
IN
l
l
l
l
l
l
ENABLE Input High Voltage
ENABLE Input Low Voltage
ENABLE Input Current
Shutdown Input High Voltage
Shutdown Input Low Voltage
Shutdown Input Current
Drain Sense Threshold Voltage
3.5
2
ENH
ENL
0.6
1
V
I
EN
0V < V < V
μA
V
IN
S
S
V
V
SDH
0.8
1
V
SDL
I
SD
0V < V < V
μA
IN
V
SEN
80
75
100
100
120
125
mV
mV
l
l
I
Drain Sense Input Current
Gate Voltage Above Supply
0V < V
< V
0.1
μA
SEN
SEN
S
l
l
l
V
GATE
– V
V = 5V
6
7.5
15
7
8.3
18
9
15
25
V
V
V
S
S
V = 6V
S
V = 12V
S
l
l
V
Status Output Low Voltage
Status Output Leakage Current
Turn-ON Time
I
= 400μA
= 12V
0.05
0.4
1
V
STAT
STAT
ON
STAT
I
t
V
μA
STAT
V = 5V, C
= 1000pF
GATE
Time for V
Time for V
S
> V + 2V
30
100
110
450
300
1000
μs
μs
GATE
GATE
S
> V + 5V
S
V = 12V, C
= 1000pF
GATE
S
Time for V
Time for V
> V + 5V
20
50
80
160
200
500
μs
μs
GATE
GATE
S
S
> V + 10V
t
t
t
Turn-OFF Time
V = 5V, C
= 1000pF, Time for V < 1V
GATE
10
10
5
36
28
25
23
17
13
60
60
40
40
40
35
μs
μs
μs
μs
μs
μs
OFF
S
GATE
V = 12V, C
S
= 1000pF, Time for V
< 1V
GATE
GATE
Short-Circuit Turn-OFF Time
Shutdown Turn-OFF Time
V = 5V, C
S
= 1000pF, Time for V
< 1V
SC
GATE
GATE
V = 12V, C
S
= 1000pF, Time for V < 1V
GATE
5
GATE
V = 5V, C
S
= 1000pF, Time for V
< 1V
SD
GATE
GATE
V = 12V, C
S
= 1000pF, Time for V
< 1V
GATE
GATE
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.
1154fb
3
LTC1154
TYPICAL PERFORMANCE CHARACTERISTICS
Standby Supply Current
Supply Current ON
High Side Gate Voltage
24
22
20
18
16
14
12
10
8
50
45
40
35
30
25
20
15
10
5
1000
900
800
700
600
500
400
300
200
100
0
T
= 25°C
V
A
= 0V
A
IN
T
= 25°C
6
0
0
0
5
10
15
20
0
5
10
15
15
15
20
0
5
10
15
20
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
LTC1154 • TPC01
LTC1154 • TPC02
LTC1154 • TPC03
Input Threshold Voltage
Drain Sense Threshold Voltage
Low Side Gate Voltage
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
150
140
130
120
110
100
90
30
27
24
21
V
ON
18
15
V
OFF
12
9
80
70
6
3
0
60
50
0
5
10
SUPPLY VOLTAGE (V)
20
0
2
4
6
8
10
0
5
10
15
20
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
LTC1154 • TPC04
LTC1154 • TPC06
-5$ꢀꢀꢁꢂꢃtꢃ51$ꢄꢁ
Short-Circuit Turn-OFF Delay
Time
Turn-ON Time
Turn-OFF Time
1000
900
800
700
600
500
400
300
200
100
0
50
45
40
35
30
25
20
15
10
5
50
45
40
35
30
25
20
15
10
5
C
GATE
= 1000pF
C
GATE
= 1000pF
C
= 1000pF
GATE
TIME FOR V
< 1V
TIME FOR V
< 1V
GATE
GATE
V
SEN
= V – 1V
S
NO EXTERNAL DELAY
V
GS
= 5V
V
= 2V
GS
0
0
0
5
10
SUPPLY VOLTAGE (V)
20
0
5
10
15
20
0
5
10
15
20
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
LTC1153 • TPC07
LTC1154 • TPC08
LTC1154 • TPC09
1154fb
4
LTC1154
TYPICAL PERFORMANCE CHARACTERISTICS
Standby Supply Current
Supply Current ON
Input ON Threshold Voltage
50
45
40
35
30
25
20
15
10
5
1000
900
800
700
600
500
400
300
200
100
0
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
V
V
= 0V
= 0V
V
V
= 5V
= 0V
IN
EN
IN
EN
V
S
= 5V
V
S
= 18V
V
= 12V
= 5V
S
V
S
= 18V
V
S
V
S
= 5V
0
–50
0
25
50
75 100 125
–25
–50 –25
0
25
50
75 100 125
–50 –25
0
25
50
75 100 125
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
LTC1154 • TPC10
LTC1154 • TPC11
LTC1154 • TPC12
Shutdown Threshold Voltage
ENABLE Threshold Voltage
Gate Drive Current
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
1000
100
10
V
S
= 12V
T
= 25°C
A
V
= 18V
S
DISABLE
V
S
= 12V
V
V
= 5V
S
S
= 18V
V
S
= 5V
1
ENABLE
0.1
–50 –25
0
25
50
75 100 125
–50 –25
0
25
50
75 100 125
0
4
8
12
16
20
TEMPERATURE (°C)
TEMPERATURE (°C)
GATE VOLTAGE ABOVE SUPPLY (V)
LTC1154 • TPC13
LTC1154 • TPC14
LTC1154 • TPC15
PIN FUNCTIONS
Input and Shutdown Pins
ENABLE Input Pin
TheLTC1154inputpinisactivehighandactivatesallofthe
protection and charge pump circuitry when switched ON.
The shutdown pin is designed to immediately disable the
switch if a secondary fault condition (over temperature,
etc.) is detected. The LTC1154 logic and shutdown inputs
are high impedance CMOS gates with ESD protection
diodes to ground and supply and therefore should not be
forced beyond the power supply rails. The shutdown pin
should be connected to ground when not in use.
The ENABLE input can be used to enable a number of
LTC1154 high side switches in banks or to provide a sec-
ondary means of control. It can also act as an inverting
input. The ENABLE input is a high impedance CMOS gate
withESDclampdiodestogroundandsupplyandtherefore
should not be forced beyond the power supply rails. This
pin should be grounded when not in use.
1154fb
5
LTC1154
PIN FUNCTIONS
Gate Drive Pin
Drain Sense Pin
Thegatedrivepiniseitherdriventogroundwhentheswitch
isturnedOFFordrivenabovethesupplyrailwhentheswitch
is turned ON. This pin is a relatively high impedance when
driven above the rail (the equivalent of a few hundred kΩ).
Care should be taken to minimize any loading of this pin
by parasitic resistance to ground or supply.
The drain sense pin is compared against the supply pin
voltage. If the voltage at this pin is more than 100mV
below the supply pin, the input latch will be reset and the
MOSFET gate will be quickly discharged. Cycle the input,
or ENABLE input, to reset the short-circuit latch and turn
the MOSFET back on.
This pin is also a high impedance CMOS gate with ESD
protection and therefore should not be forced beyond the
power supply rails. To defeat the overcurrent protection,
short the drain sense to supply.
Supply Pin
The supply pin of the LTC1154 serves two vital purposes.
The first is obvious: it powers the input, gate drive, regula-
tion and protection circuitry. The second purpose is less
obvious: it provides a Kelvin connection to the top of the
drain sense resistor for the internal 100mV reference.
Some loads, such as large supply capacitors, lamps, or
motors require high inrush currents. An RC time delay
can be added between the sense resistor and the drain
sense pin to ensure that the drain sense circuitry does not
false-trigger during start-up. This time constant can be
set from a few microseconds to many seconds. However,
very long delays may put the MOSFET in risk of being
destroyed by a short-circuit condition. (see Applications
Information Section).
The LTC1154 is designed to be continuously powered so
that the gate of the MOSFET is actively driven at all times.
If it is necessary to remove power from the supply pin
and then re-apply it, the input pin (or enable pin) should
be cycled a few milliseconds after the power is re-applied
to reset the input latch and protection circuitry. Also, the
inputandenablepinsshouldbeisolatedwith10kresistors
to limit the current flowing through the ESD protection
diodes to the supply pin.
Status Pin
The status pin is an open-drain output which is driven
low whenever a fault condition is detected. A 51k pull-up
resistor should be connected between this output and a
logic supply. The status pins of multiple LTC1154s can be
OR’d together if independent fault sensing is not required.
No connection is required to this pin when not in use.
The supply pin of the LTC1154 should never be forced
below ground as this may result in permanent damage to
the device. A 300Ω resistor should be inserted in series
with the ground pin if negative supply voltage transients
are anticipated.
BLOCK DIAGRAM
DRAIN
SENSE
ANALOG SECTION
V
S
SHUTDOWN
TTL-TO-CMOS
CONVERTER
SHUTDOWN
10μs
DELAY
COMP
LOW STANDBY
CURRENT
REGULATOR
100mV
REFERENCE
GATE CHARGE
AND DISCHARGE
CONTROL LOGIC
GATE
ANALOG DIGITAL
R
INPUT
LATCH
TTL-TO-CMOS
CONVERTER
VOLTAGE
REGULATORS
INPUT
OSCILLATOR
AND CHARGE
PUMP
FAST/SLOW
GATE CHARGE
LOGIC
ONE
SHOT
S
ENABLE
GND
FAULT DETECTION
AND STATUS
OUTPUT DRIVER
STATUS
LTC1154 • BD01
1154fb
6
LTC1154
TRUTH TABLE
The Truth Table demonstrates how the LTC1154 receives
inputs and returns status information to the μP. The
ENABLE and input signal from the μP controls the switch
in its normal operating mode, where the rise and fall
time of the gate drive are controlled to limit EMI and RFI
emissions. The shutdown and overcurrent detection cir-
cuitry however, switch the gate off at a much higher rate
to limit the exposure of the MOSFET switch and the load
to dangerous conditions. The status pin remains high as
long as the switch is operating normally, and is driven
low only when a fault condition is detected. Note that the
shutdown pin is edge-sensitive and latches the output off
even if the shutdown pin returns to a low state.
INPUTS
OUTPUTS
SD GATE STATUS
SWITCH
CONDITION
IN
X
EN
H
X
X
X
L
L
L
L
H
L
H
H
H
L
SWITCH OFF
SWITCH OFF
SWITCH ON
L
H
H
L
L
SWITCH LATCHED OFF
(OVER CURRENT)
H
L
L
L
SWITCH LATCHED OFF
(SHUTDOWN)
L = LOGIC LOW
H = LOGIC HIGH
X = IRRELEVANT
= EDGE TRIGGERED
OPERATION
The LTC1154 is a single micropower MOSFET driver
with built-in protection, status feedback and gate charge
pump. The LTC1154 consists of the following functional
blocks:
from each other so that the noise generated by the charge
pump logic is not coupled into the 100mV reference or
the analog comparator.
Gate Charge Pump
TTL and CMOS Compatible Inputs
Gate drive for the MOSFET switch is produced by an adap-
tive charge pump circuit which generates a gate voltage
substantially higher than the power supply voltage. The
charge pump capacitors are included on chip and there-
fore no external components are required to generate the
gate drive.
TheLTC1154inputandshutdowninputhavebeendesigned
to accommodate a wide range of logic families. Both in-
put thresholds are set at about 1.3V with approximately
100mV of hysteresis.
A low standby current voltage regulator provides continu-
ousbiasfortheTTL-to-CMOSconverter.TheTTL-to-CMOS
converter output enables the rest of the circuitry. In this
way the power consumption is kept to a minimum in the
standby mode.
Drain Current Sense
The LTC1154 is configured to sense the current flowing
into the drain of the power MOSFET in a high side ap-
plication. An internal 100mV reference is compared to
the drop across a sense resistor (typically 0.002Ω to
0.10Ω) in series with the drain lead. If the drop across
this resistor exceeds the internal 100mV threshold, the
input latch is reset and the gate is quickly discharged via
a large N-channel transistor.
ENABLE Input
The ENABLE input is CMOS compatible and inhibits the
input signal whenever it is held logic high. This input
should be grounded when not in use.
Internal Voltage Regulation
Controlled Gate Rise and Fall Times
The output of the TTL-to-CMOS converter drives two
regulated supplies which power the low voltage CMOS
logicandanalogblocks.Theregulatoroutputsareisolated
WhentheinputisswitchedONandOFF, thegateischarged
bytheinternalchargepumpanddischargedinacontrolled
1154fb
7
LTC1154
OPERATION
manner. The charge and discharge rates have been set to
minimize RFI and EMI emissions in normal operation. If
a short-circuit or current overload condition is encoun-
tered, the gate is discharged very quickly (typically a few
microseconds) by a large N-channel transistor.
Status Output Driver
The status circuitry continuously monitors the fault de-
tection logic. This open-drain output is driven low when
the gate of the MOSFET is driven low by the protection
circuitry. The status circuitry is reset along with the input
latch when the input, or ENABLE input, is cycled.
APPLICATIONS INFORMATION
MOSFET and Load Protection
stored energy to ground. Many inductive loads have these
diodes included. If not, a diode of the proper current rating
should be connected across the load, as shown in Figure
2, to safely divert the stored energy.
TheLTC1154protectsthepowerMOSFETswitchbyremov-
ingdrivefromthegateassoonasanovercurrentcondition
isdetected. Resistiveandinductiveloadscanbeprotected
with no external time delay in series with the drain sense
pin. Lamp loads, however, require that the overcurrent
protection be delayed long enough to start the lamp but
short enough to ensure the safety of the MOSFET.
12V
+
100μF
IN
V
S
0.036Ω
IRFZ24
EN
DS
G
LTC1154
Resistive Loads
STATUS
GND
15V
Loads that are primarily resistive should be protected with
asshortadelayaspossibletominimizetheamountoftime
thattheMOSFETissubjectedtoanoverloadcondition.The
drain sense circuitry has a built-in delay of approximately
10μs to eliminate false triggering by power supply or load
transient conditions. This delay is sufficient to “mask”
short load current transients and the starting of a small
capacitor (<1μF) in parallel with the load. The drain sense
pincanthereforebeconnecteddirectlytothedraincurrent
sense resistor as shown in Figure 1.
SD
R
LOAD
C
≤ 1μF
LOAD
12Ω
LTC1154 • F01
Figure 1. Protecting Resistive Loads
12V
+
100μF
IN
V
S
0.036Ω
IRFZ24
Inductive Loads
EN
DS
G
Loadsthatareprimarilyinductive,suchasrelays,solenoids
and stepper motor windings should be protected with as
short a delay as possible to minimize the amount of time
that the MOSFET is subjected to an overload condition.
The built-in 10μs delay will ensure that the overcurrent
protection is not false-triggered by a supply or load
transient. No external delay components are required as
shown in Figure 2.
LTC1154
STATUS
15V
GND
SD
12V, 1A
SOLENOID
1N5400
LTC1154 • F02
Large inductive loads (>0.1mH) may require diodes con-
nected directly across the inductor to safely divert the
Figure 2. Protecting Inductive Loads
1154fb
8
LTC1154
APPLICATIONS INFORMATION
Capacitive Loads
Lamp Loads
Largecapacitiveloads,suchascomplexelectricalsystems
with large bypass capacitors, should be powered using
the circuit shown in Figure 3. The gate drive to the power
MOSFET is passed through an RC delay network, R1 and
C1, which greatly reduces the turn-on ramp rate of the
switch. And since the MOSFET source voltage follows the
gatevoltage,theloadispoweredsmoothlyandslowlyfrom
ground. This dramatically reduces the start-up current
flowingintothesupplycapacitor(s)which,inturn,reduces
supplytransientsandallowsforsloweractivationofsensi-
tive electrical loads. (Diode, D1, provides a direct path for
the LTC1154 protection circuitry to quickly discharge the
gate in the event of an overcurrent condition).
Theinrushcurrentcreatedbyalampduringturn-oncanbe
10to20timesgreaterthantheratedoperatingcurrent.The
circuit shown in Figure 4 shifts the current limit threshold
up by a factor of 11:1 (to 30A) for 100ms when the bulb
is first turned on. The current limit then drops down to
2.7A after the inrush current has subsided.
12V
+
470μF
10k
0.036Ω
IN
V
S
100k
EN
DS
G
VN2222LL
0.1μF
LTC1154
STATUS
GND
1M
SD
MTP3055EL
12V
+
9.1V
470μF
IN
V
S
0.036Ω
C
R
D
100k
D
12V/1A
BULB
0.01μF
EN
DS
G
D1
1N4148
LTC1154
LTC1154 • F04
STATUS
GND
R1
100k
R2
Figure 4. Lamp Driver with Delayed Protection
100k
MTP3055E
OUT
SD
C1
0.33μF
Selecting R and C
D
D
15V
Figure 5 is a graph of normalized overcurrent shutdown
time versus normalized MOSFET current. This graph is
+
C
LOAD
100μF
used to select the two delay components, R and C ,
D
D
LTC1154 • F03
which make up a simple RC delay between the drain sense
resistor and the drain sense input.
Figure 3. Powering Large Capacitive Loads
The RC network, R and C , in series with the drain sense
10
1
D
D
inputshouldbesettotripbasedontheexpectedcharacter-
isticsoftheloadafter start-up.Withthiscircuit,itispossible
to power a large capacitive load and still react quickly to
an overcurrent condition. The ramp rate at the output of
the switch as it lifts off ground is approximately:
0.1
0.01
dV/dt = (V
– V )/(R1 • C1)
TH
GATE
Andthereforethecurrentflowingintothecapacitorduring
start-up is approximately:
1
10
100
I
= C
• dV/dt
START-UP
LOAD
MOSFET CURRENT (1 = SET CURRENT)
LTC1154 • F05
Using the values shown in Figure 3, the start-up current
is less than 100mA and does not false-trigger the drain
sense circuitry which is set at 2.7A with a 1ms delay.
Figure 5. Overcurrent Shutdown Time vs MOSFET Current
1154fb
9
LTC1154
APPLICATIONS INFORMATION
12V
The Y axis of the graph is normalized to one RC time
constant. The X axis is normalized to the current. (The
set current is defined as the current required to develop
100mV across the drain sense resistor).
5V
+
10μF
120k
10k
10k
10k
IN
V
S
0.05Ω
5V
μP OR
CONTROL
LOGIC
EN
DS
G
Notethattheshutdowntimeisshorterforincreasinglevels
of MOSFET current. This ensures that the total energy
dissipated by the MOSFET is always within the bounds
established by the manufacturer for safe operation. (See
MOSFET data sheet for further information).
LTC1154
STATUS
GND
MTP12N06
15V
SD
LOAD
10k
300Ω
Using a Speed-Up Diode
LTC1154 • F07
To reduce the amount of time that the power MOSFET is
in a short-circuit condition, “bypass” the delay resistor
with a small signal diode as shown in Figure 6. The diode
will engage when the drop across the drain sense resistor
exceedsabout0.7V,providingadirectpathtothesensepin
anddramaticallyreducingtheamountoftimetheMOSFET
is in an overload condition. The drain sense resistor value
Figure 7. Reverse Battery Protection
SincetheLTC1154drawsverylittlecurrentwhileinnormal
operation, the drop across the ground resistor is minimal.
The 5V μP (or control logic) is protected by the 10k resis-
tors in series with the input and status pins.
Current Limited Power Supplies
12V
The LTC1154 requires at least 3.5V at the supply pin to
ensure proper operation. It is therefore necessary that the
supplytotheLTC1154beheldhigherthan3.5Vatalltimes,
even when the output of the switch is short circuited to
ground. The output voltage of a current limited regulator
may drop very quickly during short-circuit and pull the
supplypinoftheLTC1154below3.5Vbeforetheshutdown
circuitry has had time to respond and remove drive from
the gate of the power MOSFET. A supply filter should be
+
100μF
1N4148
IN
V
S
0.036Ω
IRF530
0.01μF
100k
EN
DS
G
LTC1154
STATUS
GND
15V
SD
LOAD
LTC1154 • F06
5V/2A
REGULATOR
>7V
+
+
Figure 6. Using a Speed-Up Diode
*20Ω
10μF
0.1Ω
100μF
is selected to limit the maximum DC current to 2.8A. The
diode conducts when the drain current exceeds 20A and
reduces the turn-off time to 15μs.
+
1N4148
100k
47μF*
IN
V
S
0.1μF
EN
DS
G
LTC1154
Reverse Battery Protection
IRLR024
STATUS
GND
The LTC1154 can be protected against reverse battery
conditions by connecting a resistor in series with the
ground lead as shown in Figure 7. The resistor limits the
supply current to less than 50mA with –12V applied.
SHORT-
CIRCUIT
SD
LTC1154 • F08
*SUPPLY FILTER COMPONENTS
Figure 8. Supply Filter for Current Limited Supplies
1154fb
10
LTC1154
APPLICATIONS INFORMATION
added as shown in Figure 8 which holds the supply pin of
theLTC1154highlongenoughfortheovercurrentshutdown
circuitry to respond and fully discharge the gate.
be able to hold the supply pin of the LTC1154 above 3.5V
sufficiently long that this extra filtering is not required.
Because the LTC1154 is micropower in both the standby
and ON state, the voltage drop across the supply filter is
lessthan2mV,anddoesnotsignificantlyaltertheaccuracy
of the 100mV drain sense threshold voltage.
Five volt linear regulators with small output capacitors are
the most difficult to protect as they can “switch” from a
voltage mode to a current limited mode very quickly. The
largeoutputcapacitorsonmanyswitchingregulatorsmay
TYPICAL APPLICATIONS
High Side Driver with Thermal Shutdown
High Side Driver with Overvoltage Shutdown
6V
4.75V TO 5.25V
5V
5V
+
+
100μF
10μF
IN
V
IN
V
S
S
100Ω
5.6V
μP OR
CONTROL
LOGIC
μP OR
CONTROL
LOGIC
EN
DS
G
EN
DS
G
LTC1154
LTC1154
STATUS†
IRLZ24
STATUS†
IRLD024
30k
GND
SD
GND
SD
6V
LOAD
5V
LOAD
PTC
THERMISTOR
(100°C)*
*RL3006-50-100-25-PT0 KEYSTONE
SWITCH IS SHUTDOWN WHEN V > 5.7V
S
LTC1154 • TA03
LTC1154 • TA05
†
A 51k pullup resistor should be connected between Status Output and 5V Logic Supply.
High Side Driver with Undervoltage Shutdown
24V to 28V High Side Switch with Thermal Shutdown
5V
24V TO 28V
+
+
10k
3k
100μF
100μF
1N4148*
+
+
1μF**
5V
5V
18V
10μF
2N2907
IN
V
IN
V
S
S
μP OR
CONTROL
LOGIC
μP OR
CONTROL
LOGIC
EN
DS
G
EN
DS
G
LTC1154
LTC1154
STATUS†
IRLZ24
STATUS†
MTP12N06
200k
GND
SD
GND
SD
PTC
THERMISTOR
(100°C)*
6V
LOAD
24V TO 28V
LOAD
10k
*OPTIONAL IF SUPPLY VOLTAGE LESS THAN 6V.
*KEYSTONE RL2006-100-100-30-PT.
MOUNT ON MOSFET OR LOAD HEAT SINK
**CAPACITOR CHARGED TO SUPPLY VOLTAGE.
SHUTDOWN OCCURS WHEN SUPPLY VOLTAGE
DROPS BY 0.6V.
LTC1154 • TA06
LTC1154 • TA04
1154fb
11
LTC1154
TYPICAL APPLICATIONS
24V to 28V Switch with Bootstrapped Supply
High Side Relay Driver with Overcurrent
Protection and Status Feedback
24V TO 28V
12V
+
+
100k
100μF
100μF
2Ω
0.02Ω
+
5V
5V
18V
10μF
10k
6.2k
IN
V
IN
V
S
S
0.01μF
1N4148
μP OR
CONTROL
LOGIC
μP OR
CONTROL
LOGIC
1N4148
EN
DS
G
EN
DS
G
MTD3055E
15V
LTC1154
LTC1154
STATUS†
MTP15N06E
STATUS†
TO 12V
LOAD
200k
GND
SD
GND
SD
PTC
THERMISTOR
(100°C)*
1N4001
24V TO 28V
LOAD
*KEYSTONE RL2006-100-100-30-PT.
COIL CURRENT LIMITED TO 350mA.
CONTACT CURRENT LIMITED TO 5A.
MOUNT ON MOSFET OR LOAD HEAT SINK.
LTC1154 • TA07
LTC1154 • TA08
I
= 60MA, I
= 1mA.
Q(OFF)
Q(ON)
†
A 51k pullup resistor should be connected between Status Output and 5V Logic Supply.
“4-Cell-to-5V” Extremely Low Voltage Drop Regulator with
Overcurrent Shutdown, Status Feedback, Ramped Turn-ON
and 8μA Standby Current
4-CELL
BATTERY
PACK
+
100μF
0.036Ω
5V
IN
V
S
μP OR
CONTROL
LOGIC
IRLR024
1N4148
100k 100k
0.22μF
EN
DS
G
200pF
10k
LTC1154
STATUS†
1
8
3
4
5V/2A
470μF
LT1431
7
GND
SD
+
ESR < 0.5Ω
6
5
LTC1154 • TA09
1154fb
12
LTC1154
TYPICAL APPLICATIONS
Bank Controlled High Side Switches with “Global” Thermal
and Overvoltage Shutdown
12V
IN
V
S
+
100Ω
470μF
EN
DS
G
LTC1154
STATUS
GND
IRLR024
IRLR024
IRLR024
IRLR024
15V
15V
15V
15V
SD
OUTPUT 1
OUTPUT 2
OUTPUT 3
IN
V
S
5V
EN
DS
G
LTC1154
51k
STATUS
GND
SD
μP OR
CONTROL
LOGIC
IN
V
S
EN
DS
G
LTC1154
STATUS
GND
SD
IN
V
S
120k
EN
DS
G
LTC1154
STATUS
GND
SD
OUTPUT 4
PTC
THERMISTOR
(100°C)*
15V
*KEYSTONE RL2006-100-100-30-PT.
MOUNT ON COMMON HEAT SINK.
LTC1154 • TA10
1154fb
13
LTC1154
TYPICAL APPLICATIONS
12V Step-Up Regulator with Ultralow Standby Current,
Overcurrent Protection and Status Feedback
1N5820
50μH
0.02Ω
IRLZ24
12V/1A
330μF
5V
+
+
20Ω
470μF
5
+
10.72k
1%
+
10k
1N4148
V
47μF
IN
150μF
4
2
V
SW
ON/OFF
STATUS
IN
V
S
LT1070
0.22μF
FB
1N4148
100k 100k
V
GND
C
1
51k
EN
DS
G
3
1.24k
1%
LTC1154
STATUS
GND
1k
0.1μF
SD
1μF
LTC1154 • TA11
12V Step-Up Regulator with 1A Overcurrent Protection,
Switch Status Feedback and Ramped Output
1N5820
50μH
5V
+
+
150μF
330μF
0.1Ω
5
1N4148
10k
V
IN
10.72k
1%
4
V
SW
FB
ON/OFF
STATUS
IN
V
S
LT1070
2
0.1μF
1N4148
V
C
1
GND
51k
EN
DS
G
1.24k
1%
3
LTC1154
100k
100k
STATUS
GND
IRF530
1k
1μF
12V
SD
12V/1A
47μF
+
0.22μF
LTC1154 • TA12
1154fb
14
LTC1154
PACKAGE DESCRIPTION
N8 Package
8-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510)
.400*
(10.160)
MAX
8
7
6
5
4
.255 .015*
(6.477 0.381)
1
2
3
.130 .005
.300 – .325
.045 – .065
(3.302 0.127)
(1.143 – 1.651)
(7.620 – 8.255)
.065
(1.651)
TYP
.008 – .015
(0.203 – 0.381)
.120
.020
(0.508)
MIN
(3.048)
MIN
+.035
.325
–.015
.018 .003
(0.457 0.076)
.100
(2.54)
BSC
+0.889
8.255
(
)
N8 1002
–0.381
NOTE:
INCHES
1. DIMENSIONS ARE
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
1154fb
15
LTC1154
PACKAGE DESCRIPTION
S8 Package
8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610)
.189 – .197
(4.801 – 5.004)
.045 .005
NOTE 3
.050 BSC
7
5
8
6
.245
MIN
.160 .005
.150 – .157
(3.810 – 3.988)
NOTE 3
.228 – .244
(5.791 – 6.197)
.030 .005
TYP
1
3
4
2
RECOMMENDED SOLDER PAD LAYOUT
.010 – .020
(0.254 – 0.508)
× 45°
.053 – .069
(1.346 – 1.752)
.004 – .010
(0.101 – 0.254)
.008 – .010
(0.203 – 0.254)
0°– 8° TYP
.016 – .050
(0.406 – 1.270)
.050
(1.270)
BSC
.014 – .019
(0.355 – 0.483)
TYP
NOTE:
INCHES
1. DIMENSIONS IN
(MILLIMETERS)
2. DRAWING NOT TO SCALE
3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
SO8 0303
1154fb
16
LTC1154
REVISION HISTORY (Revision history begins at Rev B)
REV
DATE
DESCRIPTION
PAGE NUMBER
B
4/11
Updated Graph TPC05
4
Updated SCSI Termination Typical Application
Updated Related Parts
18
18
1154fb
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
17
LTC1154
TYPICAL APPLICATIONS
Auto-Reset High Side Switch with Overcurrent and Overcurrent Temperature Shutdown
12V
+
100μF
R
T
1M
1M**
0.036Ω
ON/OFF
IN
V
S
EN
DS
G
LTC1154
+
C
T
STATUS
GND
MTP12N06
100μF**
18V
VN2222LL
200k
PTC
SD
12V
LOAD
THERMISTOR
(100°C)*
*KEYSTONE RL2006-100-100-30-PT.
**AUTO-RESET PERIOD ≈ 800ms WITH COMPONENTS SHOWN
LTC1154 • TA13
SCSI Termination Power Switch with 1A Overcurrent Shutdown, Auto-Reset and Load Soft-Start
1N5817
0.1Ω
MTD3055EL
ꢂꢅꢆꢁ7ꢇꢀ"
5V
+
+
100μF
10μF
1M
1M
20Ω
10k
1N4148
+
ON/OFF
IN
V
S
47μF
0.1μF
1N4148
100k 100k
EN
DS
G
LTC1154
+
45"564
1μF
VN2222LL
0.22μF
GND
SD
-5$ꢀꢀꢁꢂꢃtꢃ5"ꢀꢂ
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC4440/LTC4440-5
High Speed, High Voltage High Side Gate Driver
Up to 80V Supply Voltage, 8V ≤ V ≤ 15V, 2.4A Peak Pull-Up/1.5Ω
CC
Peak Pull-Down
LTC4441/LTC4441-1
LT1910
N-Channel MOSFET Gate Driver
Protected High Side Gate Driver
Up to 25V Supply Voltage, 5V ≤ V ≤ 25V, 6A Peak Output Current
CC
Up to 48V Supply Voltage, Short Circuit Protected
LTC4446
High Voltage Synchronous N-Channel MOSFET
Driver without Shoot Thru Protection
Up to 100V Supply Voltage, 7.2V ≤ V ≤ 13.5V, 3A Peak Pull-Up/0.55Ω
CC
Peak Pull-Down
LTC4444/LTC4444-5
LTC4442/LTC4449
High Voltage Synchronous N-Channel MOSFET
Driver with Shoot Thru Protection
Up to 100V Supply Voltage, 4.5V/7.2V ≤ V ≤ 13.5V, 3A Peak Pull-Up/
CC
0.55Ω Peak Pull-Down
High Speed Synchronous N-Channel MOSFET
Driver
Up to 38V Supply Voltage, 4.5V/6V ≤ V ≤ 9.5V, 3.2A Peak Pull-Up/
CC
4.5A Peak Pull-Down
1154fb
LT 0411 REV B • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
18
●
●
© LINEAR TECHNOLOGY CORPORATION 1992
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
相关型号:
LTC1154CS8#PBF
LTC1154 - High-Side Micropower MOSFET Driver; Package: SO; Pins: 8; Temperature Range: 0°C to 70°C
Linear
LTC1154CS8#TR
LTC1154 - High-Side Micropower MOSFET Driver; Package: SO; Pins: 8; Temperature Range: 0°C to 70°C
Linear
LTC1154CS8#TRPBF
LTC1154 - High-Side Micropower MOSFET Driver; Package: SO; Pins: 8; Temperature Range: 0°C to 70°C
Linear
LTC1154HS8
LTC1154 - High-Side Micropower MOSFET Driver; Package: SO; Pins: 8; Temperature Range: -40°C to 125°C
Linear
LTC1154HS8#PBF
LTC1154 - High-Side Micropower MOSFET Driver; Package: SO; Pins: 8; Temperature Range: -40°C to 125°C
Linear
LTC1155CN8#PBF
LTC1155 - Dual High Side Micropower MOSFET Driver; Package: PDIP; Pins: 8; Temperature Range: 0°C to 70°C
Linear
©2020 ICPDF网 联系我们和版权申明