19-1903; Rev 3; 10/03
Dual USB Switch with Fault
Blanking and Autoreset
General Description
The MAX1823 is a dual, current-limited switch with
autoreset specifically made for USB applications. The
autoreset feature latches the switch off if the output is
shorted, saving system power. The switch reactivates
when the short circuit is removed. Each channel is guar-
anteed to supply 720mA and meet USB specifications.
Low quiescent supply current (50µA) and standby current
(3µA) conserve battery power in portable applications.
The MAX1823 has multiple safety features to ensure
that the USB port is protected. Built-in thermal-overload
protection limits power dissipation and junction temper-
ature. Accurate internal current-limiting circuitry pro-
tects the input supply against both overload and
short-circuit conditions. Independent fault signals
(FAULTA and
FAULTB)
notify the microprocessor (µP)
when a thermal-overload, current-limit, undervoltage-
lockout (UVLO), or short-circuit fault occurs. A 20ms
fault-blanking feature ignores momentary faults, such
as those caused when hot swapping a capacitive load,
preventing false alarms to the host system. The
MAX1823A/MAX1823B also block reverse current (cur-
rent from OUT_ to IN_) while in shutdown.
The MAX1823 is available in a space-saving 10-pin
µMAX package. The MAX1823/MAX1823A are enabled
with an active-low signal, and the MAX1823B/MAX1823H
are enabled with an active-high signal. For a single ver-
sion of this device, refer to the MAX1946 data sheet. For
a triple version, refer to the MAX1940 data sheet.
o
Autoreset Feature Saves Power
o
Guaranteed 720mA Load per Channel
o
Built-In 20ms Fault Blanking
o
Compliant to USB Specification
o
Blocks Reverse Current in Shutdown
(MAX1823A/MAX1823B)
o
4V to 5.5V Input Voltage Range
o
Independent Shutdown Control
(MAX1823/MAX1823A—Active Low)
(MAX1823B/MAX1823H—Active High)
o
Independent
FAULT
Indicator Outputs
o
Thermal-Overload Protection
o
50µA Quiescent Current (Both Switches On)
o
3µA Standby Current
o
UL Recognized
Features
o
Dual USB Switch in Tiny 10-Pin µMAX Package
MAX1823/MAX1823A/MAX1823B/MAX1823H
Ordering Information
PART
MAX1823EUB
MAX1823AEUB
MAX1823BEUB
MAX1823HEUB
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
10 µMAX
10 µMAX
10 µMAX
10 µMAX
Applications
USB Ports and Hubs
Notebook and Desktop Computers
PDAs and Palmtop Computers
Docking Stations
Typical Operating Circuit
INA
IN
OUTA
USB
PORT A
Pin Configuration
TOP VIEW
*(ONA) ONA
1
INA
2
IN
3
INB
4
*(ONB) ONB
5
10
FAULTA
INPUT
4V TO 5.5V
INB
MAX1823
MAX1823A
FAULTA
FAULTB
ONA
ONB
ONA
ONB
GND
OUTB
9
8
7
6
OUTA
GND
OUTB
FAULTB
USB
PORT B
MAX1823
MAX1823A
MAX1823B
MAX1823H
µMAX
*( ) ARE FOR MAX1823B/MAX1823H.
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Dual USB Switch with Fault
Blanking and Autoreset
MAX1823/MAX1823A/MAX1823B/MAX1823H
ABSOLUTE MAXIMUM RATINGS
IN, INA, INB,
ONA, ONB,
ONA, ONB
OUTA, OUTB to GND ...........................................-0.3V to +6V
FAULTA, FAULTB
to GND..........................-0.3V to (V
IN_
+ 0.3V)
MAX1823/MAX1823H, INA, IN to OUTA;
INB, IN to OUTB ...................................................-0.3V to +6V
MAX1823A/MAX1823B, INA, IN to OUTA;
INB, IN to OUTB (when disabled, Note 3)...............-6V to +6V
INA, IN to OUTA; INB, IN to OUTB
(when enabled, Note 4)..............................-1.5A to +1.5A
RMS
FAULTA, FAULTB
Current .................................................20mA
Continuous Power Dissipation (T
A
= +70°C)
10-Pin µMAX (derate 5.6mW/°C above +70°C) ...........444mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+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
(Circuit of Figure 1, V
IN
= V
INA
= V
INB
= 5V,
ONA
=
ONB
= GND (MAX1823/MAX1823A), ONA = ONB = IN (MAX1823B/MAX1823H),
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Supply Voltage Range
T
A
= +25°C, each switch,
MAX1823/MAX1823H
T
A
= +25°C, each switch,
MAX1823A/MAX1823B
Switch On-Resistance
R
ON
T
A
= 0°C to +85°C, each switch,
MAX1823/MAX1823H
T
A
= 0°C to +85°C, each switch,
MAX1823A/MAX1823B
Standby Supply Current
ON_
= IN_ (MAX1823/MAX1823A), ON_ =
GND (MAX1823B/MAX1823H)
I
OUTA
= I
OUTB
= 0A, one channel on
I
OUTA
= I
OUTB
= 0A, both channels on
ON_
= IN_ (MAX1823/MAX1823A), ON_ = GND
(MAX1823B/MAX1823H), V
OUTA
= V
OUTB
= 0V,
T
A
= +25
o
C
OUT_ Off-Leakage Current
ON_
= IN_ (MAX1823/MAX1823A), ON_ =
GND (MAX1823B/MAX1823H),
V
OUTA
= V
OUTB
= 0V, T
A
= 0
o
C to +85
o
C
Undervoltage-Lockout Threshold
Continuous Load Current
Continuous Current Limit
Short-Circuit Current Limit
I
LIM
I
SHORT
V
IN
- V
OUT_
= 0.5V
V
OUT_
= 0V (I
OUT
pulsing)
V
OUT_
= 0V (I
OUT
pulsing)
V
UVLO
Rising edge, 3% hysteresis
3.0
720
0.72
0.8
0.90
1.2
0.35
1.20
1.6
0.02
3.4
10.00
3.8
V
mA
A
A
PEAK
A
RMS
3
SYMBOL
CONDITIONS
MIN
4.0
75
90
TYP
MAX
5.5
105
120
mΩ
135
165
10
µA
UNITS
V
Quiescent Supply Current
40
50
0.02
80
100
1.00
µA
µA
2
_______________________________________________________________________________________
Dual USB Switch with Fault
Blanking and Autoreset
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V
IN
= V
INA
= V
INB
= 5V,
ONA
=
ONB
= GND (MAX1823/MAX1823A), ONA = ONB = IN (MAX1823B/MAX1823H),
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Short-Circuit Detect Threshold
Continuous Current-Limit
Blanking Timeout Period
Short-Circuit Blanking Timeout
Period
Turn-On Delay
Output Rise Time
t
ON
t
RISE
SYMBOL
(Note 1)
From continuous current-limit condition to
FAULT_
assertion
From short-circuit current-limit condition to
FAULT_
assertion
R
OUT_
= 10kΩ,
does not include
rise time
MAX1823/MAX1823H
MAX1823A/MAX1823B
10
7.5
0.5
0.3
CONDITIONS
MIN
TYP
1
20
18
1.2
0.8
2.5
0.8
3.0
ms
R
OUT
_ = 10Ω, does not include fall time (from
ON_
(MAX1823A) or ON_ (MAX1823B)
deasserted to V
OUT
= 90% of V
IN_
)
R
OUT_
= 10Ω, from 90% to 10% of V
OUT_
(MAX1823/MAX1823H)
Output Fall Time
t
FALL
R
OUT_
= 10Ω, from 90% to 10% of V
OUT_
(MAX1823A/MAX1823B)
15
o
C hysteresis
V
IN_
= 4V to 5.5V
V
IN_
= 4V to 5.5V
ON_
= GND or IN_ (MAX1823/MAX1823A),
ON_ = GND or IN_ (MAX1823B/MAX1823H)
I
SINK
= 1mA, V
IN
_ = 4V
V
IN
_ = V
FAULT_
= 5.5V
In latched-off state, V
OUT_
= 0V
In latched-off state, rising
In latched-off state, V
OUT_
> 0.5V
10
0.4
10
30
0.5
20
-1
2
0.8
+1
0.4
1
45
0.6
35
0.1
3.0
35
35.0
4.0
ms
3.0
ms
MAX
UNITS
V
ms
ms
MAX1823/MAX1823A/MAX1823B/MAX1823H
R
OUT_
= 10Ω, from 10% to 90% of V
OUT_
R
OUT
_ = 10Ω, does not include fall time (from
ON_
(MAX1823) or ON_ (MAX1823H)
deasserted to V
OUT
= 90% of V
IN_
)
Turn-Off Delay from ON
t
OFF
2.5
ms
2.8
+160
o
Thermal-Shutdown Threshold
Logic Input High Voltage
Logic Input Low Voltage
Logic Input Current
FAULT_
Output Low Voltage
FAULT_
Output High Leakage
Current
Autoreset OUT_ Current
Autoreset Threshold
Autoreset Blanking Time
C
V
V
µA
V
µA
mA
V
ms
_______________________________________________________________________________________
3
Dual USB Switch with Fault
Blanking and Autoreset
MAX1823/MAX1823A/MAX1823B/MAX1823H
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, V
IN
= V
IN
_ = V
ON
_ = 5V (MAX1823B/MAX1823H); V
IN
= V
IN
_ = 5V, ON_ = GND (MAX1823/MAX1823A),
T
A
= -40°C
to +85°C,
unless otherwise noted.) (Note 2)
PARAMETER
Supply Voltage Range
Switch On-Resistance
Standby Supply Current
R
ON
Each switch, MAX1823/MAX1823H
Each switch, MAX1823A/MAX1823B
ON_
= IN_ (MAX1823/MAX1823A),
ON_ = GND (MAX1823B/MAX1823H)
I
OUTA
= I
OUTB
= 0A, one channel on
Quiescent Supply Current
I
OUTA
= I
OUTB
= 0A, both channels on
ON_
= IN_ (MAX1823/MAX1823A),
ON_ = GND (MAX1823B/MAX1823H),
V
OUTA
= V
OUTB
= 0V
V
UVLO
I
LIM
I
SHORT
Rising edge, 3% hysteresis
V
IN_
- V
OUT_
= 0.5V
V
OUT_
= 0V (I
OUT
pulsing)
From continuous current-limit condition to
FAULT_
assertion
From short-circuit current-limit condition to
FAULT_
assertion
t
ON
R
OUT_
= 10kΩ,
does not include
rise time
MAX1823/MAX1823H
MAX1823A/MAX1823B
3.0
720
0.72
0.8
10
7.5
0.5
0.3
1.20
1.6
35
35.0
4.0
ms
3.0
100
SYMBOL
CONDITIONS
MIN
4.0
TYP
MAX
5.5
135
165
10
UNITS
V
mΩ
µA
80
µA
OUT_ Off-Leakage Current
Undervoltage-Lockout Threshold
Continuous Load Current
Continuous Current Limit
Current Limit into Short Circuit
Continuous Current-Limit
Blanking Timeout Period
Short-Circuit Blanking Timeout
Period
Turn-On Delay
10
3.8
µA
V
mA
A
A
PEAK
ms
ms
Turn-Off Delay from ON
t
OFF
R
OUT_
= 10Ω, does not include fall time
(from
ON_
(MAX1823/MAX1823A) or ON_
(MAX1823B/MAX1823H) deasserted to
V
OUT_
= 90% V
IN_
)
3
ms
4
_______________________________________________________________________________________
Dual USB Switch with Fault
Blanking and Autoreset
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V
IN
= V
IN
_ = V
ON
_ = 5V (MAX1823B/MAX1823H); V
IN
= V
IN
_ = 5V, ON_ = GND (MAX1823/MAX1823A),
T
A
= -40°C
to +85°C,
unless otherwise noted.) (Note 2)
PARAMETER
Logic Input High Voltage
Logic Input Low Voltage
Logic Input Current
FAULT_
Output Low Voltage
FAULT_
Output High Leakage
Current
Autoreset OUT_Current
Autoreset Threshold
Autoreset Blanking Time
SYMBOL
CONDITIONS
V
IN_
= 4V to 5.5V
V
IN_
= 4V to 5.5V
V
ON_
= 0V or V
IN_
I
SINK
= 1mA, V
IN_
= 4V
V
IN_
= V
FAULT_
= 5.5V
In latched-off state, V
OUT_
= 0V
In latched-off state, rising
In latched-off state, V
OUT_
> 0.5V
10
0.4
10
-1
MIN
2
0.8
+1
0.4
1
50
0.6
35
TYP
MAX
UNITS
V
V
µA
V
µA
mA
V
ms
MAX1823/MAX1823A/MAX1823B/MAX1823H
Note 1:
The output voltage at which the device transitions from short-circuit current limit to continuous current limit.
Note 2:
Specifications to -40°C are guaranteed by design, not production tested.
Note 3:
Reverse current (current from OUT_ to IN_) is blocked when disabled.
Note 4:
Forward current (current from IN_ to OUT_) is internally limited. Reverse current, from OUT_ to IN_, is not limited when the
device is enabled and must be kept below 1.5A
RMS
to prevent permanent device damage. When the MAX1823A/MAX1823B
are disabled, the switch turns off and reverse current is internally blocked.
Typical Operating Characteristics
(Circuit of Figure 1, V
IN
= V
INA
= V
INB
= 5V,
ON_ =
GND (MAX1823/MAX1823A), ON_ = IN_ (MAX1823B/MAX1823H), T
A
= +25°C,
unless otherwise noted.)
QUIESCENT CURRENT
vs. INPUT VOLTAGE
MAX1823 toc01
QUIESCENT CURRENT
vs. TEMPERATURE
MAX1823 toc02
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
ON_ = IN_ (MAX1823/MAX1823A)
ON_ = GND (MAX1823B/MAX1823H)
3.3
MAX1823 toc03
60
54
QUIESCENT CURRENT (µA)
48
42
36
30
24
18
12
6
0
0
1
2
3
4
5
6
INPUT VOLTAGE (V)
55
V
IN
_ = 5.5V
3.5
SHUTDOWN SUPPLY CURRENT (µA)
QUIESCENT CURRENT (µA)
53
51
V
IN
_ = 5V
3.1
49
V
IN
_ = 4.5V
47
2.9
2.7
45
-40
-15
10
35
60
85
TEMPERATURE (°C)
2.5
-40
-15
10
35
60
85
TEMPERATURE (°C)
_______________________________________________________________________________________
5
嵌入式系统
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