MAX892LEUA+T [MAXIM]
Switching Regulator, Current-mode, PDSO8, 1.11 MM HEIGHT, ULTRA SMALL, UMAX-8;
| 型号： | MAX892LEUA+T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Switching Regulator, Current-mode, PDSO8, 1.11 MM HEIGHT, ULTRA SMALL, UMAX-8 开关 光电二极管 |
| 文件： | 总8页 (文件大小：111K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-1223; Rev 0; 4/97
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 e s w it h Th e rm a l S h u t d o w n
1/MAX892L
_______________Ge n e ra l De s c rip t io n
____________________________Fe a t u re s
♦ Ultra-Small µMAX Package—Only 1.11mm High
♦ 2.7V to 5.5V Input Range
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.
♦ Programmable Current Limit
♦ Low 13µA Quiescent Current at V = 3.3V,
IN
0.1µA Switch Off
♦ Thermal Shutdown
The MAX891L/MAX892L’s maximum current limits are
500mA a nd 250mA, re s p e c tive ly. The c urre nt 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.
♦ FAULT Indicator Output
♦ On-Resistances:
0.12Ω (MAX891L)
0.25Ω (MAX892L)
The MAX891L/MAX892L are available in 8-pin µMAX
packages.
______________Ord e rin g In fo rm a t io n
________________________Ap p lic a t io n s
PCMCIA Slots
TEMP.
RANGE
PIN-
PACKAGE
CURRENT
LIMIT
PART
Access Bus Slots
Portable Equipment
MAX891LC/D
0°C to +70°C
Dice**
500mA
500mA
250mA
250mA
MAX891LEUA* -40°C to +85°C
MAX892LC/D 0°C to +70°C
MAX892LEUA* -40°C to +85°C
8 µMAX
Dice**
8 µMAX
* To order these units 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
OUT
OUT
FAULT
SET
IN
IN
1
2
3
4
8
7
6
5
IN
MAX891L
MAX892L
100k
FAULT
GND
ON/OFF
MAX891L
MAX892L
ON
1µF
SET
GND
µMAX
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
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 e s 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
Continuous Power Dissipation (T = +70°C)
A
ON, FAULT to GND.................................................... -0.3V to 6V
µMAX (derate 4.1mW/°C above +70°C) .......................330mW
Operating Temperature Range
SET, OUT to GND ........................................-0.3V to (V + 0.3V)
IN
Maximum Continuous Switch Current
MAX891L ..........................................................................0.75A
MAX892L ........................................................................0.375A
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 = 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
20
UNITS
V
Operating Voltage
Quiescent Current
Off-Supply Current
Off-Switch Current
Undervoltage Lockout
2.7
13
0.02
0.02
2.3
µA
µA
µA
V
V
= 5V, ON = GND, I
= 0mA
IN
OUT
1
ON = IN, V = V
= 5.5V
IN
OUT
1/MAX892L
3
ON = IN, V = 5.5V, V
= 0V
IN
OUT
Rising edge, 1% hysteresis
2.0
2.6
225
420
300
500
1.302
MAX891L
MAX892L
MAX891L
MAX892L
120
250
150
300
1.240
500
250
965
965
V
IN
= 4.5V
= 3.0V
mΩ
On-Resistance
V
IN
mΩ
V
Current-Limit-Amplifier Accuracy
Maximum Output Current
V
SET
required to turn the switch off (Note 1)
1.178
MAX891L
MAX892L
mA
MAX891L, I
MAX892L, I
= 250mA
= 125mA
840
840
1130
1130
0.8
OUT
I
to I
Current Ratio
V = 1.6V to 2.8V
OUT
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
-1
V
V
IN
V
0.01
0.5
1
3
µA
µA
V
ON
I
Bias Current
V
SET
= 1.24V, I
= 1mA, V
= 0mA
= 1.4V
= 1V
SET
OUT
I
0.4
1
FAULT Logic Output Low Voltage
FAULT Logic Output High Leakage
SINK
SET
V
= 5.5V, V
0.05
5
µA
µs
FAULT
SET
Slow-Current-Loop Response Time 20% current overdrive, V = 5V
IN
Fast-Current-Loop Response Time
2
µs
V
= 5V
= 3V
100
150
2
200
20
IN
I
= 250mA (MAX891L), or 125mA
OUT
Turn-On Time
Turn-Off Time
µs
µs
(MAX892L)
V
IN
V
= 5V
0.8
IN
2
_______________________________________________________________________________________
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 e s w it h Th e rm a l S h u t d o w n
1/MAX892L
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
3.0
50
µA
µA
µA
V
V
= 5V, ON = GND, I
= 0mA
IN
OUT
2.2
ON = IN, V = V
= 5.5V
IN
OUT
8
ON = IN, V = 5.5V, V
= 0V
IN
OUT
Rising edge, 1% hysteresis
2.0
2.9
MAX891L
MAX892L
MAX891L
MAX892L
225
420
300
500
1.34
1210
1210
0.4
V
= 4.5V
= 3.0V
mΩ
IN
On-Resistance
V
IN
mΩ
V
Current-Limit-Amplifier Accuracy
V
SET
required to turn the switch off (Note 1)
1.14
805
805
MAX891L, I
MAX892L, I
= 250mA
= 125mA
OUT
OUT
I
to I
Current Ratio
V = 1.6V to 2.8V
OUT
A/A
OUT
SET
I
= 1mA, V
= 1.4V
V
µs
µs
FAULT Logic Output Low Voltage
Turn-On Time
SINK
SET
V
IN
= 5V
200
20
Turn-Off Time
V
IN
= 5V
0.25
Note 1: Tested with I
= 50mA for the MAX891L, 25mA for the MAX892L, and V
raised until V - V
≥ 0.8V.
OUT
SET
IN
OUT
Note 2: Parameters to -40°C are guaranteed by design, not production tested.
_______________________________________________________________________________________
3
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 e s 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
(Typical Operating Circuit, T = +25°C, unless otherwise noted.)
A
QUIESCENT CURRENT
vs. INPUT VOLTAGE
QUIESCENT CURRENT
vs. TEMPERATURE
OFF-SUPPLY CURRENT
vs. TEMPERATURE
14
12
10
8
14
0.06
0.05
0.04
0.03
0.02
13
12
11
V = 5V
IN
V = 3V
IN
6
10
4
9
8
7
0.01
0
2
0
1/MAX892L
0
1
2
3
4
5
6
-40 -20
0
20
40
60
80 100
-40 -20
0
20
40
60
80 100
INPUT VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
OFF-SWITCH LEAKAGE CURRENT
vs. TEMPERATURE
NORMALIZED ON-RESISTANCE
vs. TEMPERATURE
I
/I RATIO
OUT SET
vs. I
LIMIT
1.3
1400
0.06
0.05
0.04
0.03
0.02
I
= 1/2I
LIM
LOAD
1.2
1.1
1.0
1200
1000
800
0.9
600
0.8
0.7
0.6
400
200
0
0.01
0
-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-ON TIME
vs. TEMPERATURE
TURN-OFF TIME
vs. TEMPERATURE
1.2
1.0
0.8
0.6
0.4
0.2
0
260
240
220
4
3
2
1
0
I
= I
I
= I
LOAD LIM
LOAD LIM
I
LIMIT
V = 5V
IN
200
180
V = 3V
IN
V = 3V
IN
160
140
120
100
80
V = 5V
IN
V = 5V
IN
60
-40 -20
0
20
40
60
80 100
0
1
2
3
4
5
6
-40 -20
0
20
40
60
80 100
OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
4
_______________________________________________________________________________________
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 e s w it h Th e rm a l S h u t d o w n
1/MAX892L
____________________________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 )
(Typical Operating Circuit, T = +25°C, unless otherwise noted.)
A
CURRENT-LIMIT RESPONSE
CURRENT-LIMIT RESPONSE
(MAX891L, R = 0.8Ω)
(MAX891L, R = 0.5Ω)
L
L
A
5V
5V
A
B
C
B
C
0A
0V
0A
0V
2µs/div
1µs/div
B: I , 2A/div
OUT
C
IN
= 47µF, C = 0.1µF
OUT
C
IN
= 47µF, C = 0.1µF
B: I , 2A/div
OUT
OUT
C: V , 5V/div
OUT
A: V , 500mV/div, AC COUPLED
IN
A: V , 500mV/div, AC COUPLED
IN
C: V , 5V/div
OUT
SWITCH TURN-ON TIME
A
B
20µs/div
V
IN
= 5V, I = I
OUT LIM
A: V , 2V/div
ON
B: V , 2V/div
OUT
SWITCH TIMING CHARACTERISTICS
SWITCH TURN-OFF TIME
A
B
C
D
0A
A
B
0V
0V
0V
0V
0V
2µs/div
50µs/div
V = 5V
IN
V
IN
= 5V, I = I
OUT LIM
A: I , 0.1A/div
LOAD
C: V , 5V/div
OUT
A: V , 2V/div
ON
B: V , 5V/div
ON
D: V
, 5V/div
B: V , 2V/div
OUT
FAULT
_______________________________________________________________________________________
5
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 e s 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. See Setting the
Current Limit section.
5
SET
Fault-Indicator Output. This open-drain output goes low when in current limit or when the die temperature
exceeds +135°C.
6
FAULT
7, 8
OUT
Switch Output. P-channel MOSFET drain. Bypass OUT with a 0.1µF capacitor to ground.
_______________De t a ile d De s c rip t io n
The MAX891L/MAX892L P-channel MOSFET power
switches limit output current to a user-programmed
le ve l. When the output current is increased beyond
the s e t c urre nt le ve l, the c urre nt is a ls o inc re a s e d
MAX891L
MAX892L
P
1/MAX892L
IN
throug h the re p lic a s witc h (I
/965) a nd throug h
OUT
OUT
R
(Figure 1). The current-limit error amplifier com-
SET
FAULT
P
pares the voltage across R
to the internal 1.24V ref-
SET
erence and regulates the current back to the lesser of
the programmed current limit (I ) or the maximum
N
REPLICA
AMPLIFIER
LIMIT
current limit (I ).
MAX
ON
These switches are not bidirectional; therefore, the
input voltage 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 MAX891L/MAX892L feature internal current-limit-
ing c irc uitry with ma ximum p rog ra mma b le va lue s
ON
CURRENT-LIMIT
AMPLIFIER
R
SET
(I ) of 500mA and 250mA, respectively. For best
MAX
1.24V
p e rforma nc e , s e t the c urre nt limit (I ) b e twe e n
LIMIT
0.2I
≤ I
≤ I
. This current limit remains in
MAX
LIMIT
MAX
HOT
effect throughout the input supply-voltage range.
GND
Program the current limit with a resistor (R
SET to ground (Figure 2) as follows:
) from
SET
CONTROL
CIRCUITRY
ON
I
= I
/ I
SET
RSET = 1.240 / ISET
is the desired current limit, and I
LIMIT RATIO
Figure 1. Functional Diagram
where I
is
RATIO
LIMIT
the I
to I
current ratio (965).
OUT
SET
S h o rt -Circ u it P ro t e c t io n
For a high ∆V /∆t during an output short-circuit condi-
DS
The MAX891L/MAX892L a re s hort-c irc uit-p rote c te d
switches. In the event of an output short circuit or cur-
rent-overload condition, the current through the switch is
limited by the internal current-limiting error amplifier to
tion, the switch turns off and disconnects the input sup-
ply from the output. The current-limiting amplifier then
slowly turns the switch on with the output current limited
to 1.5 x I . When the fault condition is removed, the
LIMIT
1.5 x I . When the fault condition is removed, the
LIMIT
current limit is set back to I . Refer to the Current-
LIMIT
replica error amplifier sets the current limit back to
Limit Re s p ons e g ra p hs in the Typ ic a l Op e ra ting
Characteristics.
I
.
LIMIT
6
_______________________________________________________________________________________
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 e s w it h Th e rm a l S h u t d o w n
1/MAX892L
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.
MAX891L
MAX892L
La yo u t a n d Th e rm a l-Dis s ip a t io n
SET
Co n s id e ra t io n
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 dissi-
pates and channels heat away. Calculate maximum
power as follows:
Figure 2. Setting the Current Limit
P = I2
x R
ON
LIM
Th e rm a l S h u t d o w n
where R
is the on-resistance of the switch.
ON
The MAX891L/MAX892L feature thermal shutdown. The
switch turns off when the junction temperature exceeds
+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.
When the output is short circuited, voltage drop across
the switch equals the input supply. Hence, the power
dissipated across the switch increases, as does the die
temperature. If the fault condition 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 helps dissipate additional
heat.
Fa u lt In d ic a t o r
The MAX891L/MAX892L provide a fault output (FAULT).
This open-drain output goes low when in current limit or
when the die temperature exceeds +135°C. During
start-up, FAULT is low until the switch is fully on and no
over-current condition exists. 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
SUBSTRATE CONNECTED TO GND
__________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 input voltage drop during momentary output
short-circuit conditions, connect a capacitor from IN to
GND. A 1µF ceramic capacitor is adequate for most
applications; however, higher capacitor values further
reduce voltage drop at the input.
_______________________________________________________________________________________
7
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 e s w it h Th e rm a l S h u t d o w n
__________________________________________________Ta p e -a n d -Re e l In fo rm a t io n
4.0 ±0.1
1.0 ±0.1
1.75 ±0.1
2.0 ±0.05
1.5 +0.1/-0.0 DIAMETER
A
3.5 ±0.05
8.0 ±0.3
2.2 ±0.1
0.5 RADIUS
TYPICAL
A0
1.0 MINIMUM
4.0 ±0.1
A
Bo
Ao = 3.1mm ±0.1
Bo = 2.7mm ±0.1
Ko = 1.2mm ±0.1
NOTE: DIMENSIONS ARE IN MM.
AND FOLLOW EIA481-1 STANDARD.
Ko
1/MAX892L
0.30 ±0.05
0.8 ±0.05
0.30R MAX.
________________________________________________________P a c k a g e In fo rm a t io n
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
© 1997 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
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