MAX890LESA [MAXIM]
1A, Current-Limited, High-Side P-Channel Switch with Thermal Shutdown; 1A ，限流型，高边P沟道开关，带有热关断
| 型号： | MAX890LESA |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | 1A, Current-Limited, High-Side P-Channel Switch with Thermal Shutdown |
| 文件： | 总8页 (文件大小：137K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-1146; Rev 2; 11/98
1 A, Cu rre n t -Lim it e d , Hig h -S id e
P -Ch a n n e l S w it c h w it h Th e rm a l S h u t d o w n
MAX890L
Ge n e ra l De s c rip t io n
____________________________Fe a t u re s
♦ 2.7V to 5.5V Input Range
The MAX890L smart, low-voltage, P-channel, MOSFET
power switch is intended for high-side load-switching
applications. This switch operates with inputs from 2.7V
to 5.5V, making it ideal for both 3V and 5V systems.
Internal current-limiting circuitry protects the input sup-
ply against overload. Thermal-overload protection limits
power dissipation and junction temperatures.
♦ Programmable Current Limit
♦ Low Quiescent Current
10µA (typ) at V = 3.3V
IN
0.1µA (typ) with Switch Off
♦ Thermal Shutdown
The MAX890L’s maximum current limit is 1A. The cur-
re nt limit throug h the switc h is progra mme d with a
resistor from SET to ground. The quiescent supply cur-
rent is a low 10µA. When the switch is off, the supply
current decreases to 0.1µA.
♦ FAULT Indicator Output
♦ 0.09Ω (typ) On-Resistance
The MAX890L is available in an 8-pin SO package.
________________________Ap p lic a t io n s
Ord e rin g In fo rm a t io n
PCMCIA Slots
TEMP.
RANGE
PIN-
PACKAGE
CURRENT
LIMIT
PART*
Access Bus Slots
Portable Equipment
MAX890LC/D
0°C to +70°C
Dice**
8 SO
1A
1A
MAX890LESA -40°C to +85°C
* To order this unit in tape and reel, add (-T) to the end of the part
number.
** Dice are tested at T = +25°C.
A
Typ ic a l Op e ra t in g Circ u it
P in Co n fig u ra t io n
TOP VIEW
INPUT
IN
OUT
OUT
ON
OUTPUT
0.1µF
FAULT
8
IN
IN
1
2
3
4
IN
MAX890L
OUT
7
100kΩ
MAX890L
FAULT
GND
ON/OFF
OUT
SET
ON
6
5
1µF
SET
GND
R
SET
SO
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
1 A, Cu rre n t -Lim it e d , Hig h -S id e
P -Ch a n n e l S w it c h w it h Th e rm a l S h u t d o w n
ABSOLUTE MAXIMUM RATINGS
IN to GND ..................................................................-0.3V to 6V
Operating Temperature Range
ON, FAULT to GND ....................................................-0.3V to 6V
MAX890LESA ....................................................-40°C to +85°C
Storage Temperature Range ........................... -65°C to +150°C
Lead Temperature (soldering, 10sec) . ...........................+300°C
SET, OUT to GND ...................................... -0.3V to (V + 0.3V)
IN
Maximum Continuous Switch Current ..................................1.5A
Continuous Power Dissipation (T = +70°C)
A
SO (derate 5.88mW/°C above +70°C) ..........................471mW
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.
MAX890L
ELECTRICAL CHARACTERISTICS
(V = 3V, T = 0°C to +85°C, unless otherwise noted. Typical values are at T = +25°C.)
IN
A
A
PARAMETER
CONDITIONS
MIN
TYP
MAX
5.5
UNITS
V
Operating Voltage
Quiescent Current
Off-Supply Current
Off-Switch Current
Undervoltage Lockout
2.7
13
0.03
0.04
2.4
20
µA
µA
µA
V
V
IN
= 5V, ON = GND, I
= 0
OUT
1
ON = IN, V = V
= 5.5V
IN
OUT
15
ON = IN, V = 5.5V, V
= 0
IN
OUT
Rising edge, 1% hysteresis
2.0
2.6
V
= 4.5V
= 3.0V
75
130
150
1.302
IN
On-Resistance
mΩ
V
IN
90
Current-Limit-Amplifier Threshold
Maximum Output Current Limit
V
SET
required to turn the switch off (Note 1)
1.178
970
1.240
1
V
A
I
to I
Current Ratio
I
= 500mA, V > 1.6V
OUT
1110
1300
0.8
A/A
V
OUT
SET
OUT
V
IN
= 2.7V to 5.5V
= 2.7V to 3.6V
= 4.5V to 5.5V
= 5.5V
ON Input Low Voltage
ON Input High Voltage
ON Input Leakage
V
IN
2.0
2.4
V
V
IN
V
ON
0.01
0.5
1
3
µA
µA
V
I
Bias Current
V
SET
= 1.24V, I
= 0; V = V
OUT IN OUT
SET
I
= 1mA, V
= 1.4V
SET
0.4
1
FAULT Logic Output Low Voltage
FAULT Logic Output High Leakage Current
Slow-Current-Loop Response Time
Fast-Current-Loop Response Time
SINK
V
FAULT
= 5.5V, V
= 1V
0.05
5
µA
µs
SET
20% current overdrive, V = 5V
CC
2
µs
V
= 5V, I
= 3V, I
= 5V
= 500mA
= 500mA
120
185
5
200
IN
OUT
Turn-On Time
Turn-Off Time
µs
µs
V
IN
OUT
V
IN
2
Note 1: Tested with I
= 100mA and V
raised until V - V
≥ 0.8V.
OUT
SET
IN
OUT
2
_______________________________________________________________________________________
1 A, Cu rre n t -Lim it e d , Hig h -S id e
P -Ch a n n e l S w it c h w it h Th e rm a l S h u t d o w n
MAX890L
ELECTRICAL CHARACTERISTICS
(V = 3V, T = -40°C to +85°C, unless otherwise noted.) (Note 2)
IN
A
PARAMETER
CONDITIONS
MIN
TYP
MAX
5.5
UNITS
V
Operating Voltage
Quiescent Current
Off-Supply Current
Off-Switch Current
Undervoltage Lockout
2.9
50
µA
µA
µA
V
V
IN
= 5V, ON = GND, I
= 0
OUT
2.2
ON = IN, V = V
= 5.5V
IN
OUT
15
ON = IN, V = 5.5V, V
= 0
IN
OUT
Rising edge, 1% hysteresis
2.0
2.9
V
= 4.5V
= 3.0V
130
150
1.34
1390
0.4
IN
On-Resistance
mΩ
V
IN
Current-Limit-Amplifier Threshold
V
SET
required to turn the switch off (Note 1)
1.14
925
V
A/A
V
I
to I
Current Ratio
I
= 500mA, V
> 1.6V
OUT
SET
OUT
OUT
I
= 1mA, V
= 1V
FAULT Logic Output Low Voltage
Turn-On Time
SINK
SET
V
IN
= 5V
200
20
µs
Turn-Off Time
V
IN
= 5V
1
µs
Note 2: Specifications to -40°C are guaranteed by design, not production tested.
_______________________________________________________________________________________
3
1 A, Cu rre n t -Lim it e d , Hig h -S id e
P -Ch a n n e l S w it c h w it h Th e rm a l S h u t d o w n
__________________________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s
(T = +25°C, unless otherwise noted.)
A
OFF-SUPPLY CURRENT
vs. TEMPERATURE
QUIESCENT CURRENT
vs. INPUT VOLTAGE
QUIESCENT CURRENT
vs. TEMPERATURE
14
100
10
1
14
ON = GND
12
13
12
11
I
= 0
OUT
V = 5V
IN
MAX890L
10
8
V = 3V
IN
6
10
4
9
8
7
0.1
2
0
0.01
-40 -20
0
20
40
60
80 100
0
1
2
3
4
5
6
-40 -20
0
20
40
60
80 100
INPUT VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
NORMALIZED ON-RESISTANCE
vs. TEMPERATURE
I
/I RATIO
OFF-SWITCH CURRENT
vs. TEMPERATURE
OUT SET
vs. I
LIMIT
1000
100
10
1.3
1400
I
= 1/2I
LIMIT
OUT
1.2
1.1
1.0
1200
1000
800
0.9
600
1
0.8
0.7
0.6
400
200
0
0.1
0.01
-40 -20
0
20
40
60
80 100
-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
TURN-OFF TIME
vs. TEMPERATURE
TURN-ON TIME
vs. TEMPERATURE
1.2
1.0
0.8
0.6
0.4
0.2
0
8
260
240
220
I
= I
I
= I
LOAD LIMIT
LOAD LIMIT
I
7
6
5
4
3
LIMIT
V = 3V
IN
200
180
V = 5V
IN
160
140
120
100
80
V = 3V
IN
V = 5V
IN
2
1
V = 5V
IN
0
60
0
1
2
3
4
5
6
-40 -20
0
20
40
60
80 100
-40 -20
0
20
40
60
80 100
OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
4
_______________________________________________________________________________________
1 A, Cu rre n t -Lim it e d , Hig h -S id e
P -Ch a n n e l S w it c h w it h Th e rm a l S h u t d o w n
MAX890L
____________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s (c o n t in u e d )
(T = +25°C, unless otherwise noted.)
A
CURRENT-LIMIT RESPONSE
CURRENT-LIMIT RESPONSE
(R = 0.6Ω)
L
(R = 0.3Ω)
L
A
B
5V
A
B
5V
0A
0V
C
C
0V, 0A
2µs/div
= 100µF, C = 0.1µF
2µs/div
= 100µF, C = 0.1µF
OUT
B: I , 1A/div
OUT
B: I , 5A/div
OUT
C
IN
C
IN
OUT
C: V , 2V/div
OUT
C: V , 2V/div
A: V , 1V/div, AC COUPLED
IN
A: V , 1V/div, AC COUPLED
IN
OUT
LOAD-TRANSIENT RESPONSE
A
0A
0V
B
5ms/div
V
IN
= 5V
B: V RIPPLE,
OUT
A: I = 0mA TO 750mA,
OUT
200mV/div, AC COUPLED
0.5A/div
SWITCH TURN-OFF TIME
SWITCH TURN-ON TIME
A
A
B
0V
B
0V
2µs/div
20µs/div
V
= 5V, I = I
OUT LIMIT
IN
V
= 5V, I = I
OUT LIMIT
IN
A: V , 2V/div
B: V , 2V/div
ON
A: V , 2V/div
B: V , 2V/div
ON
OUT
OUT
_______________________________________________________________________________________
5
1 A, Cu rre n t -Lim it e d , Hig h -S id e
P -Ch a n n e l S w it c h w it h Th e rm a l S h u t d o w n
P in De s c rip t io n
PIN
1, 2
3
NAME
IN
FUNCTION
Input. P-channel MOSFET source. Bypass IN with a 1µF capacitor to ground.
Active-Low Switch On Input. A logic low turns the switch on.
Ground
ON
4
GND
Set Current-Limit Input. A resistor from SET to ground sets the current limit for the switch.
= 1.38 x 103 / I
where I is the desired current limit in amperes.
5
6, 7
8
SET
OUT
R
SET
LIMIT,
LIMIT
MAX890L
Switch Output. P-channel MOSFET drain. Bypass OUT with a 0.1µF capacitor to ground.
Fault-Indicator Output. This open-drain output goes low when in current limit or when the die temperature
exceeds +135°C.
FAULT
De t a ile d De s c rip t io n
The MAX890L P-channel MOSFET power switch limits
output current to a programmed level. When the output
current is increased beyond the programmed current
P
OUT
IN
limit, or 1A (I
the re p lic a s witc h (I
), the current also increases through
MAX890L
MAX
FAULT
P
/1110) a nd throug h R
OUT
SET
(Figure 1). The current-limit error amplifier compares
the voltage across R to the internal 1.24V reference,
SET
N
REPLICA
AMPLIFIER
and regulates the current back to the lesser of the pro-
grammed limit (I ) or 1A.
ON
LIMIT
This switch is not bidirectional; therefore, the input volt-
age must be higher than the output voltage.
P
SET
S e t t in g t h e Cu rre n t Lim it
The MAX890L features internal current-limiting circuitry
ON
CURRENT-LIMIT
AMPLIFIER
with a maximum programmable value (I ) of 1A. For
MAX
R
SET
1.24V
best performance, set the current limit (I ) between
LIMIT
0.2 I
≤ I
≤ I . This current limit remains in
MAX
MAX
LIMIT
effect throughout the input supply-voltage range.
HOT
Program the current limit with a resistor (R
SET to ground (Figure 2) as follows:
) from
SET
GND
CONTROL
CIRCUITRY
ON
I
= I
/ 1110
SET
LIMIT
3
R
= 1.24V / I = 1.38 x 10 / I
8 LIMIT
SET
where I
is the desired current limit.
LIMIT
Figure 1. Functional Diagram
S h o rt -Circ u it P ro t e c t io n
The MAX890L is a short-circuit-protected switch. In the
event of an output short circuit or current-overload con-
dition, the current through the switch is limited by the
from the output. The current-limiting amplifier then slow-
ly turns the switch on with the output current limited to
internal current-limiting error amplifier to 1.5 x I
.
LIMIT
1.5 x I . When the fault condition is removed, the
LIMIT
When the fault condition is removed, the replica error
amplifier will set the current limit back to I
current limit is set back to I . Refer to Output Short-
LIMIT
.
LIMIT
Circuit Fast-Loop Response and Output Short-Circuit
Slow-Loop Re s p ons e in the Typ ic a l Op e ra ting
Characteristics.
For a high dV /dt during an output short-circuit condi-
DS
tion, the switch turns off and disconnects the input supply
6
_______________________________________________________________________________________
1 A, Cu rre n t -Lim it e d , Hig h -S id e
P -Ch a n n e l S w it c h w it h Th e rm a l S h u t d o w n
MAX890L
Ou t p u t Ca p a c it o r
Connect a 0.1µF capacitor from OUT to GND. One
function of this capacitor is to prevent inductive para-
sitics from pulling OUT negative during turn-off.
MAX890L
La yo u t a n d Th e rm a l-Dis s ip a t io n
Co n s id e ra t io n
SET
To take full advantage of the switch-response time to
R
SET
output short-circuit conditions, it is very important to
keep all traces as short as possible to reduce the effect
of undesirable parasitic inductance. Place input and
output capacitors as close as possible to the device
(no more than 5mm).
GND
Under normal operating conditions, the package can
dissipate and channel heat away. Calculate the maxi-
mum power as follows:
Figure 2. Setting the Current Limit
P = I2
x R
ON
LIMIT
where R
is the on-resistance of the switch.
ON
Th e rm a l S h u t d o w n
When the output is short circuited, the voltage drop
across the switch equals the input supply. Hence, the
power dissipated across the switch increases, as does
the d ie te mp e ra ture . If the fa ult c ond ition is not
removed, the thermal-overload-protection circuitry turns
the switch off until the die temperature falls by 10°C. A
ground plane in contact with the device will help dissi-
pate additional heat.
The MAX890L features thermal shutdown. The switch
turns off whe n the junc tion te mp e ra ture e xc e e d s
+135°C. Once the device cools by 10°C, the switch
turns back on. If the fault short-circuit condition is not
removed, the switch will cycle on and off, resulting in a
pulsed output.
Fa u lt In d ic a t o r
The MAX890L provides a fault output (FAULT). This
open-drain output goes low when in current limit or
when the die temperature exceeds +135°C. A 100kΩ
pull-up resistor from FAULT to IN provides a logic-
control signal.
Ch ip In fo rm a t io n
TRANSISTOR COUNT: 396
Ap p lic a t io n s In fo rm a t io n
In p u t Ca p a c it o r
To limit the input voltage drop during momentary output
short-circuit conditions, connect a capacitor from IN to
GND. A 1µF ceramic capacitor will be adequate for
most applications; however, higher capacitor values
will further reduce the voltage drop at the input.
_______________________________________________________________________________________
7
1 A, Cu rre n t -Lim it e d , Hig h -S id e
P -Ch a n n e l S w it c h w it h Th e rm a l S h u t d o w n
________________________________________________________P a c k a g e In fo rm a t io n
MAX890L
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
8 _____________________Ma x im In t e g ra t e d P ro d u c t s , 1 2 0 S a n Ga b rie l Drive , S u n n yva le , CA 9 4 0 8 6 4 0 8 -7 3 7 -7 6 0 0
© 1998 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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