19-1223; Rev 0; 4/97
Current-Limited, High-Side
P-Channel Switches with Thermal Shutdown
_______________General Description
The MAX891L/MAX892L smart, low-voltage, P-channel,
MOSFET power switches are intended for high-side
load-switching applications. These switches operate
with inputs from 2.7V to 5.5V, making them ideal for
both 3V and 5V systems. Internal current-limiting circuitry
protects the input supply against overload. Thermal-
overload protection limits power dissipation and junc-
tion temperatures.
The MAX891L/MAX892L’s maximum current limits are
500mA and 250mA, respectively. The current limit
through the switch is programmed with a resistor from
SET to ground. When the switch is on, the quiescent
supply current is a low 13µA. When the switch is off, the
quiescent current decreases to 0.1µA.
The MAX891L/MAX892L are available in 8-pin µMAX
packages.
____________________________Features
o
Ultra-Small µMAX Package—Only 1.11mm High
o
2.7V to 5.5V Input Range
o
Programmable Current Limit
o
Low 13µA Quiescent Current at V
IN
= 3.3V,
0.1µA Switch Off
o
Thermal Shutdown
o
FAULT
Indicator Output
o
On-Resistances:
0.12Ω (MAX891L)
0.25Ω (MAX892L)
MAX891L/MAX892L
________________________Applications
PCMCIA Slots
Access Bus Slots
Portable Equipment
______________Ordering Information
PART
MAX891LC/D
MAX891LEUA*
MAX892LC/D
MAX892LEUA*
TEMP.
RANGE
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
PIN-
CURRENT
PACKAGE
LIMIT
Dice**
8 µMAX
Dice**
8 µMAX
500mA
500mA
250mA
250mA
* To order these units in tape and reel, add (-T) to the end of the
part number.
** Dice are tested at T
A
= +25°C.
__________Typical Operating Circuit
__________________Pin Configuration
TOP VIEW
INPUT
IN
IN
FAULT
1µF
GND
OUT
OUTPUT
0.1µF
100k
IN
1
ON/OFF
IN
2
ON
3
SET
GND
4
5
SET
8
OUT
MAX891L
MAX892L
OUT
ON
MAX891L
MAX892L
7
OUT
6
FAULT
µMAX
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
Current-Limited, High-Side
P-Channel Switches with Thermal Shutdown
MAX891L/MAX892L
ABSOLUTE MAXIMUM RATINGS
IN to GND ..................................................................-0.3V to 6V
ON, FAULT
to GND.................................................... -0.3V to 6V
SET, OUT to GND ........................................-0.3V to (V
IN
+ 0.3V)
Maximum Continuous Switch Current
MAX891L ..........................................................................0.75A
MAX892L ........................................................................0.375A
Continuous Power Dissipation (T
A
= +70°C)
µMAX (derate 4.1mW/°C above +70°C) .......................330mW
Operating Temperature Range
MAX891LEUA/MAX892LEUA ............................-40°C to +85°C
Storage Temperature Range ............................-65°C to +150°C
Lead Temperature (soldering, 10sec) ........................... +300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
IN
= 3V,
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Operating Voltage
Quiescent Current
Off-Supply Current
Off-Switch Current
Undervoltage Lockout
V
IN
= 5V,
ON
= GND, I
OUT
= 0mA
ON
= IN, V
IN
= V
OUT
= 5.5V
ON
= IN, V
IN
= 5.5V, V
OUT
= 0V
Rising edge, 1% hysteresis
V
IN
= 4.5V
On-Resistance
V
IN
= 3.0V
Current-Limit-Amplifier Accuracy
Maximum Output Current
I
OUT
to I
SET
Current Ratio
ON
Input Low Voltage
ON
Input High Voltage
ON
Input Leakage
I
SET
Bias Current
FAULT
Logic Output Low Voltage
Slow-Current-Loop Response Time
Fast-Current-Loop Response Time
Turn-On Time
Turn-Off Time
I
OUT
= 250mA (MAX891L), or 125mA
(MAX892L)
V
IN
= 5V
V
IN
= 5V
V
IN
= 3V
0.8
MAX891L
MAX892L
MAX891L
MAX892L
1.178
2.0
CONDITIONS
MIN
2.7
13
0.02
0.02
2.3
120
250
150
300
1.240
500
250
MAX891L, I
OUT
= 250mA
MAX892L, I
OUT
= 125mA
840
840
2.0
2.4
-1
0.01
0.5
0.05
5
2
100
150
2
20
200
1
3
0.4
1
965
965
1130
1130
0.8
TYP
MAX
5.5
20
1
3
2.6
225
420
300
500
1.302
UNITS
V
µA
µA
µA
V
mΩ
mΩ
V
mA
A/A
V
V
µA
µA
V
µA
µs
µs
µs
µs
V
SET
required to turn the switch off (Note 1)
MAX891L
MAX892L
V
OUT
= 1.6V to 2.8V
V
IN
= 2.7V to 5.5V
V
IN
= 2.7V to 3.6V
V
IN
= 4.5V to 5.5V
V
ON
= 5.5V
V
SET
= 1.24V, I
OUT
= 0mA
I
SINK
= 1mA, V
SET
= 1.4V
20% current overdrive, V
IN
= 5V
FAULT
Logic Output High Leakage V
FAULT
= 5.5V, V
SET
= 1V
2
_______________________________________________________________________________________
Current-Limited, High-Side
P-Channel Switches with Thermal Shutdown
ELECTRICAL CHARACTERISTICS
(V
IN
= 3V,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 2)
PARAMETER
Operating Voltage
Quiescent Current
Off-Supply Current
Off-Switch Current
Undervoltage Lockout
V
IN
= 5V,
ON
= GND, I
OUT
= 0mA
ON
= IN, V
IN
= V
OUT
= 5.5V
ON
= IN, V
IN
= 5.5V, V
OUT
= 0V
Rising edge, 1% hysteresis
V
IN
= 4.5V
On-Resistance
On-Resistance
Current-Limit-Amplifier Accuracy
I
OUT
to I
SET
Current Ratio
FAULT
Logic Output Low Voltage
Turn-On Time
Turn-Off Time
V
IN
= 3.0V
MAX891L
MAX892L
MAX891L
MAX892L
1.14
805
805
MAX891L, I
OUT
= 250mA
MAX892L, I
OUT
= 125mA
2.0
CONDITIONS
MIN
3.0
TYP
MAX
5.5
50
2.2
8
2.9
225
420
300
500
1.34
1210
1210
0.4
200
0.25
20
UNITS
V
µA
µA
µA
V
mΩ
mΩ
V
A/A
V
µs
µs
MAX891L/MAX892L
V
SET
required to turn the switch off (Note 1)
V
OUT
= 1.6V to 2.8V
I
SINK
= 1mA, V
SET
= 1.4V
V
IN
= 5V
V
IN
= 5V
Note 1:
Tested with I
OUT
= 50mA for the MAX891L, 25mA for the MAX892L, and V
SET
raised until V
IN
- V
OUT
≥
0.8V.
Note 2:
Parameters to -40°C are guaranteed by design, not production tested.
_______________________________________________________________________________________
3
Current-Limited, High-Side
P-Channel Switches with Thermal Shutdown
MAX891L/MAX892L
__________________________________________Typical Operating Characteristics
(Typical Operating Circuit, T
A
= +25°C, unless otherwise noted.)
QUIESCENT CURRENT
vs. INPUT VOLTAGE
MAX981/2/3-01
QUIESCENT CURRENT
vs. TEMPERATURE
MAX981/2/3-02
OFF-SUPPLY CURRENT
vs. TEMPERATURE
MAX980-03
14
12
QUIESCENT
CURRENT
(µA)
10
8
6
4
2
0
0
1
2
3
4
5
6
INPUT VOLTAGE (V)
14
13
QUIESCENT CURRENT (µA)
12
11
10
9
8
7
-40
-20
0
20
40
60
80
V
IN
= 3V
V
IN
= 5V
0.06
OFF-SUPPLY CURRENT (µA)
0.05
0.04
0.03
0.02
0.01
0
100
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
TEMPERATURE (°C)
OFF-SWITCH LEAKAGE CURRENT
vs. TEMPERATURE
MAX980-04
NORMALIZED ON-RESISTANCE
vs. TEMPERATURE
I
LOAD
= 1/2I
LIM
1.2
NORMALIZED R
ON
I
OUT
/I
SET
RATIO
1.1
1.0
0.9
0.8
0.7
0.6
MAX980-05
I
OUT
/I
SET
RATIO
vs. I
LIMIT
MAX981/2/3-06
0.06
0.05
LEAKAGE CURRENT (µA)
0.04
0.03
0.02
0.01
0
-40
-20
0
20
40
60
80
1.3
1400
1200
1000
800
600
400
200
0
100
-40
-20
0
20
40
60
80
100
0
20
40
60
80
100
120
140
TEMPERATURE (°C)
TEMPERATURE (°C)
I
LIMIT
(%)
NORMALIZED OUTPUT CURRENT
vs. OUTPUT VOLTAGE
MAX890-06A
TURN-ON TIME
vs. TEMPERATURE
MAX981/2/3-07
TURN-OFF TIME
vs. TEMPERATURE
I
LOAD
= I
LIM
V
IN
= 5V
3
V
IN
= 3V
t
OFF
(µs)
2
MAX981/2/3-08
1.2
NORMALIZED OUTPUT CURRENT
1.0
0.8
0.6
0.4
0.2
V
IN
= 5V
0
0
1
2
3
4
5
6
OUTPUT VOLTAGE (V)
I
LIMIT
260
240
220
200
t
ON
(µs)
180
160
140
120
100
80
60
-40
-20
0
20
40
60
80
V
IN
= 5V
V
IN
= 3V
I
LOAD
= I
LIM
4
1
0
100
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
TEMPERATURE (°C)
4
_______________________________________________________________________________________
Current-Limited, High-Side
P-Channel Switches with Thermal Shutdown
____________________________Typical Operating Characteristics (continued)
(Typical Operating Circuit, T
A
= +25°C, unless otherwise noted.)
CURRENT-LIMIT RESPONSE
(MAX891L, R
L
= 0.8Ω)
A
5V
MAX891L/MAX892L
CURRENT-LIMIT RESPONSE
(MAX891L, R
L
= 0.5Ω)
5V
A
B
B
C
0A
0V
0A
C
0V
2µs/div
C
IN
= 47µF, C
OUT
= 0.1µF
A: V
IN
, 500mV/div, AC COUPLED
B: I
OUT
, 2A/div
C: V
OUT
, 5V/div
1µs/div
C
IN
= 47µF, C
OUT
= 0.1µF
A: V
IN
, 500mV/div, AC COUPLED
B: I
OUT
, 2A/div
C: V
OUT
, 5V/div
SWITCH TURN-ON TIME
A
B
20µs/div
V
IN
= 5V, I
OUT
= I
LIM
A: V
ON
, 2V/div
B: V
OUT
, 2V/div
SWITCH TURN-OFF TIME
SWITCH TIMING CHARACTERISTICS
A
A
0V
B
0A
0V
C
0V
B
0V
2µs/div
V
IN
= 5V, I
OUT
= I
LIM
A: V
ON
, 2V/div
B: V
OUT
, 2V/div
D
0V
50µs/div
V
IN
= 5V
A: I
LOAD
, 0.1A/div
B: V
ON
, 5V/div
C: V
OUT
, 5V/div
D: V
FAULT
, 5V/div
_______________________________________________________________________________________
5
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