19-2385; Rev 2; 11/02
Current-Limited Switch for Two USB Ports
General Description
The MAX1930 current-limited 70mΩ switch with built-in
fault blanking provides an accurate, preset 1.2A to 2.3A
current limit, making it ideal for dual USB applications.
Its low quiescent supply current (16µA) and standby
current (1µA) conserve battery power in portable appli-
cations. The MAX1930 operates with inputs from 2.7V to
5.5V, making it ideal for both 3V and 5V systems.
The MAX1930 has several safety features to ensure that
the USB port is protected. Built-in thermal-overload
protection limits power dissipation and junction tempera-
ture. The device also has accurate internal current-limiting
circuitry to protect the input supply against overload.
The MAX1930 is offered in a space-saving 8-pin SO
package and operates over the extended (-40°C to
+85°C) temperature range.
Features
o
Pin Compatible with TPS2010–TPS2013
o
Accurate Current Limit (1.2A min, 2.3A max)
o
125mΩ (max) High-Side MOSFET
o
Short-Circuit and Thermal Protection
o
Undervoltage Lockout
o
16µA Quiescent Supply Current
o
1µA (max) Standby Supply Current
o
2.7V to 5.5V Supply Range
o
UL Recognized: UL# E211395
MAX1930
Applications
Notebook Computers
USB Ports and Hubs
Docking Stations
PART
MAX1930ESA
Ordering Information
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
8 SO
Pin Configuration
TOP VIEW
INPUT
2.7V TO 5.5V
Typical Operating Circuit
IN
GND
IN
IN
1
2
8
7
OUT
OUT
OUT
OUTNC
ON
OFF
EN
GND
OUT
OUTPUT
MAX1930
MAX1930
3
6
5
EN
4
SO
________________________________________________________________
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.
Current-Limited Switch for Two USB Ports
MAX1930
ABSOLUTE MAXIMUM RATINGS
IN,
EN
to GND ..........................................................-0.3V to +6V
OUT to GND ................................................-0.3V to (V
IN
+ 0.3V)
Maximum Switch Current.........................2.3A (internally limited)
OUT Short Circuit to GND ..........................................Continuous
Continuous Power Dissipation (T
A
= +70°C)
8-Pin SO (derate 5.88mW/°C above +70°C)................471mW
Operating Temperature Range (extended) .........-40°C to +85°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
(V
IN
= 5V,
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
OPERATING CONDITION
Input Voltage
POWER SWITCH
Switch Static Drain-Source
On-Resistance
Switch Turn-On Time
Switch Turn-Off Time
ENABLE INPUT (EN)
EN
High-Level Input Voltage
EN
Low-Level Input Voltage
EN
Input Current
Startup Time
CURRENT LIMIT
Overload Output Current
Short-Circuit Output Current
SUPPLY CURRENT
Supply Current, Low-Level Input
Supply Current, High-Level Input
Supply Leakage Current
UNDERVOLTAGE LOCKOUT
Undervoltage Lockout
THERMAL SHUTDOWN
Thermal-Shutdown Threshold
165
°C
UVLO
Rising edge, 100mV hysteresis
2.0
2.4
2.6
V
I
Q
V
EN
= V
IN
= V
OUT
= 5.5V
V
EN
= 0, I
OUT
= 0
V
EN
= V
IN
= 5.5V,
V
OUT
= 0
Timer not running
Timer running
T
A
= +25°C
T
A
= 0°C to +85°C
0.002
16
35
0.01
2
15
1
25
µA
µA
µA
I
LIMIT
I
SC
Force V
OUT
to 4.5V
OUT shorted to GND
1.2
1.75
1
2.3
1.5
A
A
V
IH
V
IL
V
IN
= 2.7V to 3.6V
V
IN
= 3.7V to 5.5V
V
IN
= 2.7V to 5.5V
V
EN
= V
IN
or GND
V
IN
= 5V, C
OUT
= 150µF from
EN
driven low
to 50% full V
OUT
-1
1
2.0
2.4
0.8
+1
V
V
µA
ms
T
A
= +25°C
R
DS(ON)
t
ON
t
OFF
T
A
= 0°C to +85°C
I
LOAD
= 400mA
I
LOAD
= 400mA
3
V
IN
= 4.4V to 5.5V
V
IN
= 4.4V to 5.5V
V
IN
= 3V
72
80
6
70
100
125
150
200
20
µs
µs
mΩ
V
IN
2.7
5.5
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
Current-Limited Switch for Two USB Ports
ELECTRICAL CHARACTERISTICS
(V
IN
= 5V,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 1)
PARAMETER
OPERATING CONDITION
Input Voltage
POWER SWITCH
Switch Static Drain-Source
On-Resistance
Switch Turn-On Time
Switch Turn-Off Time
ENABLE INPUT (EN)
EN
High-Level Input Voltage
EN
Low-Level Input Voltage
EN
Input Current
CURRENT LIMIT
Overload Output Current
Short-Circuit Output Current
SUPPLY CURRENT
Supply Current, Low-Level Input
Supply Current, High-Level Input
Supply Leakage Current
UNDERVOLTAGE LOCKOUT
Undervoltage Lockout
UVLO
Rising edge, 100mV hysteresis
2.0
2.9
V
I
Q
V
EN
= V
IN
= V
OUT
= 5.5V
V
EN
= GND, I
OUT
= 0, timer not running
V
EN
= V
IN
= 5.5V, V
OUT
= GND
2
25
15
µA
µA
µA
I
LIMIT
I
SC
Force V
OUT
to 4.5V
OUT shorted to GND
1.2
2.3
1.5
A
A
V
IH
V
IL
V
IN
= 3V to 3.6V
V
IN
= 3.7V to 5.5V
V
IN
= 3V to 5.5V
V
EN
= V
IN
or GND
-1
2.0
2.4
0.8
+1
V
V
µA
R
DS(ON)
t
ON
t
OFF
V
IN
= 4.4V to 5.5V
V
IN
= 3V
I
LOAD
= 400mA
I
LOAD
= 400mA
1
125
150
200
20
mΩ
µs
µs
V
IN
3.0
5.5
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX1930
Note 1:
Specifications to -40°C are guaranteed by design, not production tested.
Typical Operating Characteristics
(Circuit of Figure 2, V
IN
= 5V, T
A
= +25°C, unless otherwise noted.)
QUIESCENT CURRENT vs. INPUT VOLTAGE
MAX1930 toc01
QUIESCENT CURRENT vs. TEMPERATURE
MAX1930 toc02
OFF SUPPLY CURRENT
vs. TEMPERATURE
EN = IN
OUT = OPEN
OFF SUPPLY CURRENT (nA)
10
MAX1930 toc03
20
18
QUIESCENT CURRENT (µA)
16
14
12
10
8
6
4
2
0
V
EN
= 0
I
OUT
= 0
18.0
I
OUT
= 0
17.5
QUIESCENT CURRENT (µA)
17.0
16.5
16.0
15.5
15.0
14.5
14.0
V
IN
= 3V
V
IN
= 5V
100
1
0.1
0.01
-40
-15
10
35
60
85
-40
-15
TEMPERATURE (°C)
10
35
TEMPERATURE (°C)
60
85
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
INPUT VOLTAGE (V)
_______________________________________________________________________________________
3
Current-Limited Switch for Two USB Ports
MAX1930
Typical Operating Characteristics (continued)
(Circuit of Figure 2, V
IN
= 5V, T
A
= +25°C, unless otherwise noted.)
OFF SWITCH CURRENT
vs. TEMPERATURE
MAX1930 toc04
NORMALIZED ON-RESISTANCE
vs. TEMPERATURE
MAX1930 toc05
NORMALIZED OUTPUT CURRENT
vs. OUTPUT VOLTAGE
I
LIMIT
(1.75A)
MAX1930 toc06
1000
EN = IN
V
OUT
= 0
OFF SWITCH CURRENT (nA)
100
1.4
1.3
1.2
NORMALIZED R
ON
1.1
1.0
0.9
0.8
0.7
I
OUT
= 850mA
1.2
NORMALIZED OUTPUT CURRENT
1.0
0.8
0.6
10
1
SHORT-CIRCUIT CURRENT
0.4
0.2
0
0.1
0.6
0.5
0.01
-40
-15
10
35
TEMPERATURE (°C)
60
85
0.4
-40
-15
10
35
60
85
TEMPERATURE (°C)
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
OUTPUT VOLTAGE (V)
TURN-ON TIME vs. TEMPERATURE
140
120
TURN-ON TIME (µs)
V
IN
= 3V
100
80
60
40
20
0
-40
-15
10
35
60
85
TEMPERATURE (°C)
V
IN
= 5V
I
OUT
= 850mA
C
OUT
= 0.1µF
MAX1930 toc07
TURN-OFF TIME vs. TEMPERATURE
8.5
8.0
TURN-OFF TIME (µs)
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
-40
-15
10
35
60
85
TEMPERATURE (°C)
0
V
IN
= 3V
V
IN
= 5V
0
I
OUT
= 850mA
C
OUT
= 0.1µF
MAX1930 toc08
CURRENT-LIMIT RESPONSE
MAX1930 toc09
160
9.0
5V
V
IN
AC-COUPLED
500mV/div
V
OUT
, 5V/div
I
OUT
, 2A/div
4µs/div
SWITCH TURN-ON TIME
MAX1930 toc10
SWITCH TURN-OFF TIME
MAX1930 toc11
STARTUP TIME
(TYPICAL USB APPLICATION)
MAX1930 toc12
V
OUT
, 5V/div
0
V
EN
, 5V/div
0
0
V
OUT
, 5V/div
0
FULL CURRENT LIMIT CHARGES CAPACITOR
V
OUT
5V/div
V
EN
, 5V/div
0
V
EN
5V/div
0
RESISTOR LOAD CURRENT
0
SHORT-CIRCUIT
CURRENT LIMIT
I
OUT
,
500mA/div
0
20µs/div
0
1µs/div
I
OUT
,
500mA/div
I
IN
1A/div
1ms/div
4
_______________________________________________________________________________________
Current-Limited Switch for Two USB Ports
Pin Description
PIN
1
2, 3
4
5
6, 7, 8
NAME
GND
IN
EN
OUTNC
OUT
Ground
Input. P-channel MOSFET source—connect all IN pins together and bypass with a 1µF capacitor to ground.
Active-Low Switch Enable Input. A logic low turns on the switch.
No Connection. This pin is not internally connected and can be connected to OUT.
Switch Output. P-channel MOSFET drain—connect all OUT pins together and bypass with a 0.1µF capacitor
to ground.
FUNCTION
MAX1930
Thermal Shutdown
IN
P
OUT
MAX1930
P
The MAX1930 has a thermal shutdown feature. The
switch turns off when the junction temperature exceeds
+165°C. When the MAX1930 cools 20°C, the switch
turns back on. If the fault short-circuit condition is not
removed, the switch cycles on and off, resulting in a
pulsed output.
REPLICA
AMPLIFIER
ON
P
Applications Information
Input Capacitor
To limit the 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 the voltage drop at the input (Figure 2).
ON
CURRENT-LIMIT
AMPLIFIER
1.24V
Output Capacitor
GND
EN
Connect a 0.1µF capacitor from OUT to GND. This
capacitor helps to prevent inductive parasitics from
pulling OUT negative during turn-off.
Layout and Thermal Dissipation
Figure 1. Functional Diagram
Detailed Description
The MAX1930 P-channel MOSFET power switch limits
output current to 1.2A (min) and 2.3A (max). When the
output current increases beyond the current limit
(I
LIMIT
), the current also increases through the replica
switch (I
OUT
/ 13,000). The current-limit error amplifier
compares the voltage to the internal 1.24V reference
and regulates the current back to the I
LIMIT
(Figure 1).
These switches are not bidirectional. As a result, the
input voltage must be higher than the output voltage.
Continuous Short-Circuit Protection
The MAX1930 is a short-circuit protected switch. In the
event of an output short-circuit condition, the current
through the switch is foldback-current-limited to 1A
continuous.
It is important to optimize the switch response time to
output short-circuit conditions by keeping 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
away). All IN and OUT pins must be connected with
short traces to the power bus. Wide power-bus planes
provide superior heat dissipation through the
MAX1930’s IN and OUT pins.
Under normal operating conditions, the package can
dissipate and channel heat away. Calculate the maxi-
mum power dissipation as follows:
P = (I
LIMIT
)
2
✕
R
ON
where I
LIMIT
is the preset current limit (2.3A max) and
R
ON
is the on-resistance of the switch (125mΩ max).
When the output is short circuited, foldback-current-lim-
iting activates and the voltage drop across the switch
equals the input supply voltage. The power dissipated
across the switch increases, as does the die tempera-
5
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