LINER LTC1981 Single and dual micropower high side switch controllers in sot-23 Datasheet

LTC1981/LTC1982
Single and Dual Micropower
High Side Switch Controllers
in SOT-23
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FEATURES
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DESCRIPTIO
No External Components Required
Internal Voltage Triplers Produce High Side
Gate Drive for Logic Level FETs
Ultralow Power:
10µA Per Driver ON Current (LTC1982)
20µA ON Current (LTC1981)
<1µA Shutdown Current
VCC Range: 1.8V to 5V
Gate Drive Outputs Driven to Ground During
Shutdown
Gate Drive Outputs Internally Clamped to 7.5V Max
“Gate Drive Ready” Output (LTC1981)
Ultrasmall Application Circuit
5-Pin SOT-23 Package (LTC1981)
6-Pin SOT-23 Package (LTC1982)
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APPLICATIO S
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Cellular Telephones
Portable POS Terminal
Handheld Battery Powered Equipment
The LTC®1981/LTC1982 are low-power, self-contained
N-channel MOSFET drivers. An internal voltage tripler
allows gates to be driven without the use of any external
components. Internal regulation circuitry allows quiescent current to drop to 10µA per driver (20µA for LTC1981)
once the gates are charged.
Low quiescent current and low shutdown current (under
1µA) make these parts ideal for battery and other power
constrained systems. The wide input voltage range accommodates a variety of battery/input configurations.
Gate drive is internally clamped to 7.5V providing protection to the external MOSFET gate. The MOSFETs can be
driven in either high side or low side mode.
The LTC1981 single driver version also includes a gate
drive ready pin and twice the drive current capacity of the
dual driver LTC1982.
The LTC1981 is available in a 5-pin SOT-23. The LTC1982
is available in a 6-pin SOT-23.
, LTC and LT are registered trademarks of Linear Technology Corporation.
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TYPICAL APPLICATIONS
Single High Side Switch Controller
Dual High Side Switch Controller
VCC
1.8V TO 5.0V
VCC
1.8V TO 5.0V
+
Q1
Si3442DV
10µF
Q1
1/2 Si6925DQ
+
10µF
Q2
1/2 Si6925DQ
5
4
6
VCC
GATE
VCC
LTC1981
100k
GATE
DRIVE
READY
SHDN
GND
SHDN
1
2
3
4
LTC1982
LOAD
GDR
5
GATE 1 GATE 2
SHDN 1
1
GND
2
LOAD 1
LOAD 2
SHDN 2
3
SHDN 1
1981/82 TA01
SHDN 2
1981/82 TA02
1
LTC1981/LTC1982
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ABSOLUTE
AXI U RATI GS
(Notes 1, 2)
Terminal Voltage
LTC1981: VCC, GATE, SHDN, GDR ........ –0.3V to 7.5V
LTC1982: VCC, GATE 1, GATE 2,
SHDN 1, SHDN 2 ................... –0.3V to 7.5V
Operating Temperature Range
LTC1981E/LTC1982E (Note 3) ............ – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
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PACKAGE/ORDER I FOR ATIO
ORDER PART
NUMBER
TOP VIEW
5 VCC
GDR 1
GND 2
4 GATE
SHDN 3
S5 PACKAGE
5-LEAD PLASTIC SOT-23
LTC1981ES5
S5 PART
MARKING
ORDER PART
NUMBER
TOP VIEW
SHDN 1 1
6 VCC
GND 2
5 GATE 1
SHDN 2 3
4 GATE 2
TJMAX = 150°C, θJA = 250°C/W
LTC1982ES6
S6 PART
MARKING
S6 PACKAGE
6-LEAD PLASTIC SOT-23
TJMAX = 150°C, θJA = 230°C/W
LTSF
LTPF
Consult factory for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V unless otherwise specified. CGATE 1 = CGATE 2 = CGATE = 1000pF.
SYMBOL
PARAMETER
VCC
Operating Supply Voltage
ICC
Supply Current
GATE 1 and GATE 2 Outputs High
GATE 1 or GATE 2 Outputs High
GATE Output High (LTC1981)
●
●
●
ISHDN
SHDN Supply Current
SHDN 1 and SHDN 2 Inputs Low
SHDN Input Low (LTC1981)
●
●
VGATE
GATE Drive Output Voltage
VCC = 1.8V
VCC = 2.7V
VCC = 3.3V
VCC = 5V
●
●
●
●
fOSC
Charge Pump Oscillator Frequency
Measured with 10k Resistor from Output to GND
600
kHz
tON
Turn-on Time into 1000pF
From SHDN 1, SHDN 2 Going High to
GATE 1, GATE 2 = VCC + 1V
110
µs
From SHDN Going High to GATE = VCC +1V (LTC1981)
85
µs
From SHDN 1, SHDN 2 Going Low to
GATE 1, GATE 2, GATE = 100mV
12
µs
tOFF
Turn-off Time into 1000pF
VIL
SHDN Input Low Voltage
VIH
CIN
IIN
SHDN Input Leakage Current
2
CONDITIONS
MIN
●
VCC = 1.8V to 5.5V
●
SHDN Input High Voltage
VCC = 1.8V to 5.5V
●
SHDN Input Capacitance
(Note 4)
TYP
1.8
17
10
17
4.27
6.40
6.90
6.90
4.50
6.75
7.25
7.25
MAX
UNITS
5.5
V
30
20
30
µA
µA
µA
1
1
µA
µA
4.75
7.10
7.50
7.50
V
V
V
V
0.4
V
1.6
5
V
pF
±1
µA
LTC1981/LTC1982
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V unless otherwise specified. CGATE 1 = CGATE 2 = CGATE = 1000pF.
(LTC1981 only)
SYMBOL
PARAMETER
CONDITIONS
MIN
VOL
GDR Output Voltage Low
ISINK = 100µA, VCC = 1.8V
●
GATE Drive Ready Trip Point
GATE Voltage Rising
VCC = 1.8V
VCC = 2.7V
VCC = 3.3V
VCC = 5V
●
●
●
●
3.85
5.78
6.17
6.17
TYP
MAX
UNITS
0.05
0.4
V
4.05
6.08
6.5
6.5
4.25
6.38
6.82
6.82
V
V
V
V
GDR Hysteresis
GATE Voltage Falling
2
%
GDR Delay
After GATE is Above the GDR Trip Threshold
10k Pull-Up to VCC
2
µs
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: All voltage values are with respect to GND.
Note 3: the LTC1982E is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 4: Guaranteed by design not subject to test.
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TYPICAL PERFOR A CE CHARACTERISTICS
100
25
VCC = 3.3V
VCC = 2.7V
TA = 25°C
GATE DRIVE CURRENT (µA)
SUPPLY CURRENT (µA)
20
LTC1981 OR
BOTH CHANNELS ON
LTC1982
15
10
EITHER CHANNEL ON
LTC1982
5
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
SUPPLY VOLTAGE (V)
VCC = 5V
VCC = 1.8V
10
1
TA = 25°C
0.1
0
5.5
0
1
2
3
4
5
6
GATE DRIVE VOLTAGE (V)
7
8
1982 G03
1982 G02
1982 G01
ISUPPLY
ISUPPLY
300
60
TA = 25°C
VCC = 3V
SHDN1 TIED
TO SHDN2
TA = 25°C
VCC = 5V
SHDN1 TIED
TO SHDN2
250
SUPPLY CURRENT (µA)
50
40
30
20
10
0
GATE Drive Current (LTC1982)
Supply Current vs Supply Voltage
8.0
7.5 TA = 25°C
7.0
GATE DRIVE VOLTAGE
6.5
(VGS COMMON SOURCE)
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
GATE DRIVE –VCC
2.0
(VGS SOURCE FOLLOWER)
1.5
1.0
0.5
0
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
SUPPLY VOLTAGE, VCC (V)
SUPPLY CURRENT (µA)
GATE DRIVE VOLTAGE (V)
GATE Drive Voltage vs Supply
Voltage
200
150
100
50
0
1
SHDN LOGIC INPUT VOLTAGE (V)
2
1981/82 G04
0
0
1
SHDN LOGIC INPUT VOLTAGE (V)
2
1981/82 G05
3
LTC1981/LTC1982
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TYPICAL PERFOR A CE CHARACTERISTICS
Turn-On Time (LTC1982)
400
7.50
40
CGATE = 1000pF
TA = 25°C
35
TURN-OFF TIME (µs)
300
250
VGS = 2V
200
CGATE = 1000pF
TA = 25°C
TIME FOR VGATE < 0.1V
150
100
30
25
20
15
10
VGS = 1V
50
0
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
SUPPLY VOLTAGE (V)
7.10
1
0.1
8
CGATE =1000pF
TA = 25°C
TIME FOR VGATE < 0.1
20
VGS = 2V
200
150
100
0
100
Turn-Off Time (LTC1981)
25
CGATE = 1000pF
TA = 25°C
VGS = 1V
50
80
1982 G08
TURN-OFF TIME (µs)
TURN-ON TIME (µs)
GATE DRIVE CURRENT (µA)
7.15
7.00
– 60 – 40 – 20 0 20 40 60
TEMPERATURE (°C)
250
7
7.20
Turn-On Time (LTC1981)
VCC = 5V
VCC = 3.3V
2
3
4
5
6
GATE DRIVE VOLTAGE (V)
7.25
7.05
300
10
1
7.30
1982 G07
VCC = 2.7V
0
7.35
0
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
SUPPLY VOLTAGE (V)
GATE Drive Current (LTC1981)
VCC = 1.8V
7.40
5
1982 G06
100
VCC = 3.3V
7.45
GATE DRIVE VOLTAGE (V)
350
TURN-ON TIME (µs)
GATE Drive Voltage vs
Temperature
Turn-Off Time (LTC1982)
15
10
5
0
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
SUPPLY VOLTAGE (V)
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
SUPPLY VOLTAGE (V)
1981/82 G09
1981/82 G10
1981/82 G11
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PIN FUNCTIONS
LTC1981:
GDR (Pin 1): Gate Drive Ready Active High Open Drain
Output. Used to indicate when the gate drive output is
greater than 90% of its final value.
VCC (Pin 5): Input Supply Voltage. Range from 1.8V to
5.5V.
GND (Pin 2): Ground.
SHDN 1 (Pin 1): SHDN 1 Active Low Input. Used to shut
down the GATE 1 charge pump and force the GATE 1
output pin to ground.
SHDN (Pin 3): SHDN Active Low Input. Used to shut down
the part and force the GATE output pin to ground.
GATE (Pin 4): Gate Drive Output to an External High Side
Switch. Fully enhanced by internal charge pump. Controlled by the SHDN input pin. Output voltage on this pin
will be approximately 2.5 times VCC or 7.25V, whichever is
less.
4
LTC1982:
GND (Pin 2): Ground.
SHDN 2 (Pin 3): SHDN 2 Active Low Input. Used to shut
down the GATE 2 charge pump and force the GATE 2
output pin to ground.
LTC1981/LTC1982
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PIN FUNCTIONS
GATE 2(Pin 4): Gate Drive Output to an External High Side
Switch. Fully enhanced by internal charge pump. Controlled by the SHDN 2 input pin. Output voltage on this pin
will be approximately 2.5 times VCC or 7.25V, whichever is
less.
GATE 1 (Pin 5): Gate Drive Output to an External High Side
Switch. Fully enhanced by internal charge pump. Controlled by the SHDN 1 input pin. Output voltage on this pin
will be approximately 2.5 times VCC or 7.25V, whichever is
less.
VCC (Pin 6): Input Supply Voltage. Range from 1.8V to␣ 5.5V.
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BLOCK DIAGRA SM
LTC1981 Single High Side Switch Driver
REGULATING
EN CHARGE PUMP
SHDN
+
15k
LTC1982 Dual High Side Switch Driver
GATE
EN
REGULATING
CHARGE
PUMP 1
30k
SHDN 1
EN
REGULATING
CHARGE
PUMP 2
30k
SHDN 2
GATE 1
GDR
–
VCC
+
–
REF
GATE 2
1981/82 BD02
1981/82 BD01
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OPERATIO
Charge Pump
To fully enhance the external N-channel switches, internal
charge pumps are used to boost the output gate drive to
approximately 2.5 times the supply voltage, or 7.25V,
whichever is less. A feedback network is used to regulate
the output gate drive. This keeps the supply current low in
addition to providing a maximum output voltage limit. The
reason for the maximum output voltage limit is to avoid
switch gate source breakdown due to excessive gate
overdrive.
The gate drive outputs (GATE 1, GATE 2, or GATE) are
controlled by the shutdown input pins (SHDN 1, SHDN 2
or SHDN). A logic high input on one of the shutdown input
pins enables the corresponding charge pump and drives
the related gate drive output pin high. A logic low input on
one of the shutdown input pins disables the corresponding charge pump and drives the related gate drive output
pin low. If shutdown input on the LTC1981 is low or both
of the shutdown input pins on the LTC1982 are low, the
part will be placed into a low current shutdown mode
(<1µA).
Gate Drive Ready (LTC1981 Only)
The gate drive ready pin (GDR) is used to indicate when the
gate drive output (GATE) is greater than 90% of its final
value. This can be useful in applications that require
knowledge of the state of the gate drive for initialization
purposes or as fault detection should something be loading the gate drive down.
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LTC1981/LTC1982
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APPLICATIONS INFORMATION
Logic-Level MOSFET Switches
The LTC1981/LTC1982 are designed to operate with logiclevel N-channel MOSFET switches. Although there is some
variation among manufacturers, logic-level MOSFET
switches are typically rated with VGS = 4V with a maximum
continuous VGS rating of ±8V. RDS (ON) and maximum
VDS ratings are similar to standard MOSFETs and there is
generally little price differential. When operating at supply
voltages of 5V or greater, care must be taken when
selecting the MOSFET. The LTC1981/LTC1982 limit the
output voltage to between 6.9V and 7.5V. The VGS developed for the MOSFET may be too low to sufficiently turn on
the MOSFET. MOSFETs rated at 2.5V, or less, will be better
suited for applications where the supply voltages approach 5V.
Powering Large Capacitive Loads
Electrical subsystems in portable battery-powered equipment are typically bypassed with large filter capacitors to
reduce supply transients and supply induced glitching. If
not properly powered however, these capacitors may
themselves become the source of supply glitching. For
example, if a 100µF capacitor is powered through a switch
with a slew rate of 0.1V/µs, the current during start-up is:
ISTART = C(∆V/∆t)
managed by the system regulator. R1 is required to
eliminate the possibility of parasitic MOSFET oscillations
during switch transitions. It is a good practice to isolate the
gates of paralleled MOSFETs with 1k resistors to decrease
the possibility of interaction between switches.
VIN
VCC
6
R1
1k
ON/OFF
Si3442DV
GATE 1
1/2 LTC1982
C1
0.1µF
SHDN 1 GND
+
CL
100µF
3.3V
LOAD
1981/82 F01
Figure 1. Powering a Large Capactive Load
Mixed 5V/3V Systems
Because the input ESD protection diodes are referenced to
the GND pin instead of the supply pin, it is possible to drive
the LTC1981/LTC1982 inputs from 5V CMOS or TTL logic
even though the LTC1981/LTC1982 is powered from a
3.3V supply as shown in Figure 2. Likewise, because the
input threshold voltage high is never greater than 1.6V, the
reverse situation is true. The LTC1981/LTC1982 can be
driven with 3V CMOS or TTL even when the supply to the
device is as high as 5V as shown in Figure 3.
3.3V
= 10A
The start up current can be substantially reduced by
limiting the slew rate at the gate of an N-channel as shown
in Figure 1. The gate drive output of the LTC1981/LTC1982
have an internal 30k resistor (15k LTC1981) in series with
each of the output gate drive pins (see Functional Block
Diagram). Therefore, it only needs an external 0.1µF
capacitor (0.22µF for the LTC1981) to create enough RC
delay to substantially slow the slew rate of the MOSFET
gate to approximately 0.6V/ms. Since the MOSFET is
operating as a source follower, the slew rate at the source
is essentially the same as that at the gate, reducing the
startup current to approximately 60mA which is easily
+
3.3µF
= (100 • 10–6)(1 • 105)
Obviously, this is too much current for the regulator (or
output capacitor) to supply and the output will glitch by as
much as a few volts.
3.3V
LT1129-3.3
VCC
5V
GATE 1
Si3442DV
1/2 LTC1982
3.3V
LOAD
SHDN 1 GND
1981/82 F02
Figure 2. Direct Interface to 5V Logic
5V
VCC
3.3V
GATE 1
Si3442DV
1/2 LTC1982
SHDN 1 GND
5V
LOAD
1981/82 F03
Figure 3. Direct Interface to 3.3V Logic
LTC1981/LTC1982
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APPLICATIONS INFORMATION
Reverse Battery Protection
The LTC1981/LTC1982 can be protected against reverse
battery conditions by connecting a 150Ω resistor in series
with the supply pin as shown in Figure 4. The resistor
limits the supply current to less than 24mA with –3.6V
applied. Because the LTC1981/LTC1982 draw very little
current while in normal operation, the drop across the
resistor is minimal. Control logic can be protected by
adding 10k resistors in series with the input pins.
VBAT
(1.8V TO 5V)
10k
0.1µF
GATE
DRIVE
READY
1
2
3
3V
GDR
GND
VCC
5
150Ω
LTC1981
SHDN
GATE
4
Si3442DV
10k
LOAD
1981/82 F04
Figure 4. Reverse Battery Protection
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PACKAGE DESCRIPTIO
Dimensions in inches (millimeters) unless otherwise noted.
S5 Package
5-Lead Plastic SOT-23
(LTC DWG # 05-08-1633)
2.60 – 3.00
(0.102 – 0.118)
1.50 – 1.75
(0.059 – 0.069)
0.35 – 0.55
(0.014 – 0.022)
0.00 – 0.15
(0.00 – 0.006)
0.09 – 0.20
(0.004 – 0.008)
(NOTE 2)
2.80 – 3.00
(0.110 – 0.118)
(NOTE 3)
0.90 – 1.45
(0.035 – 0.057)
0.35 – 0.50
0.90 – 1.30
(0.014 – 0.020)
(0.035 – 0.051)
FIVE PLACES (NOTE 2)
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DIMENSIONS ARE INCLUSIVE OF PLATING
3. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
4. MOLD FLASH SHALL NOT EXCEED 0.254mm
5. PACKAGE EIAJ REFERENCE IS SC-74A (EIAJ)
1.90
(0.074)
REF
0.95
(0.037)
REF
S5 SOT-23 0599
S6 Package
6-Lead Plastic SOT-23
(LTC DWG # 05-08-1634)
2.6 – 3.0
(0.110 – 0.118)
1.50 – 1.75
(0.059 – 0.069)
0.35 – 0.55
(0.014 – 0.022)
0.00 – 0.15
(0.00 – 0.006)
0.09 – 0.20
(0.004 – 0.008)
(NOTE 2)
0.90 – 1.45
(0.035 – 0.057)
0.35 – 0.50
0.90 – 1.30
(0.014 – 0.020)
(0.035 – 0.051) 1.90
(0.074)
SIX PLACES (NOTE 2)
REF
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DIMENSIONS ARE INCLUSIVE OF PLATING
3. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
4. MOLD FLASH SHALL NOT EXCEED 0.254mm
5. PACKAGE EIAJ REFERENCE IS SC-74A (EIAJ)
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
2.80 – 3.00
(0.110 – 0.118)
(NOTE 3)
0.95
(0.037)
REF
S6 SOT-23 0898
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LTC1981/LTC1982
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TYPICAL APPLICATIO
Driving Both High Side and Low Side Switches
VEXT
(30V MAX)
VCC
1.8 to 5.0V
10µF
LOW SIDE
LOAD
SHDN 1
1
VCC
SHDN 1
6
LTC1982
2
SHDN 2
3
GND
GATE 1
SHDN 2
GATE 2
5
4
1k
Q1
Si6954DQ
0.1µF
1k
Q2
Si6954DQ
0.1µF
HIGH SIDE
LOAD
1981/82 • TA03
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC1153/LTC1154
Single High Side Micropower MOSFET Drivers
Circuit Breaker with Auto Reset
LTC1155/LTC1255
Dual High Side Micropower MOSFET Drivers
Latchoff Current Limit
LTC1163/LTC1165
Triple 1.8V to 6V High Side MOSFET Driver
Three MOSFET Drivers in 8-Lead SO Package
LTC1623
SMBus Dual High Side Switch Controller
Uses External Switches, Two Three-State Address Pins
LTC1710
SMBus Dual Monolithic High Side Switch
Uses Internal Switches, One Three-State Address Pin
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Linear Technology Corporation
sn19812 19812fs LT/LCG 1200 4K • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com
 LINEAR TECHNOLOGY CORPORATION 2000
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