19-1518; Rev 0; 9/99
USB Current-Limited Switches
with Fault Blanking
General Description
The MAX1693/MAX1694 are current-limited, 60mΩ
switches with built-in fault blanking. Their accurate pre-
set current limit of 0.7A to 1.0A makes them ideally suit-
ed for USB applications. Their low quiescent supply
current (14µA) and shutdown current (1µA) conserve
battery power in portable applications. The MAX1693/
MAX1694 operate with inputs from +2.7V to +5.5V,
making them ideal for both +3V and +5V systems.
A fault signal notifies the microprocessor that the inter-
nal current limit has been reached. A 10ms fault-blank-
ing feature allows momentary faults (such as those
caused when hot-swapping into a capacitive load) to
be ignored, thus preventing false alarms to the host
system. This fault blanking also prevents a fault signal
from being issued when the device is powering up.
In the MAX1693, an output overcurrent condition caus-
es the switch to current limit at 0.7A to 1.0A and
FAULT
to go low after the 10ms blanking period. When the
overcurrent condition is removed,
FAULT
returns to its
high-impedance state. In the MAX1694, any overcur-
rent longer than 10ms will latch the switch open and set
FAULT
low. The latch is cleared by cycling the
ON
input or by powering up the device again. This feature
saves power by preventing the device from thermally
cycling on and off in case of a persistent short-circuit
condition.
The MAX1693/MAX1694 have several safety features to
ensure that the USB port is protected. Built-in thermal-
overload protection limits power dissipation and junc-
tion temperatures. Both devices have accurate internal
current-limiting circuitry to protect the input supply
against overload. They are available in space-saving
10-pin µMAX packages.
Features
o
Accurate Current Limit (0.7A min, 1.0A max)
o
Guaranteed 0.75A Short-Circuit Protection
o
10ms Internal Fault-Blanking Timeout
o
No Fault Signal During Power-Up
o
Latched
FAULT
Output Turns Off Power Switch
(MAX1694)
o
Thermal Shutdown Protection
o
+2.7V to +5.5V Supply Range
o
14µA Supply Current
o
Small 10-Pin µMAX Package
o
UL Recognition Pending
MAX1693/MAX1694
Applications
USB Ports and Hubs
Notebook Computers
Portable Equipment
Docking Stations
Hot Plug-In Power Supplies
Battery-Charger Circuits
Ordering Information
PART
MAX1693EUB
MAX1694EUB
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
10 µMAX
10 µMAX
Typical Operating Circuit
Pin Configuration
INPUT
+2.7V TO +5.5V
IN
OUT
OUTPUT
TOP VIEW
IN
1
OUT
IN
OUT
ON
2
3
4
5
10
OUT
9
IN
OUT
FAULT
GND
ON
OFF
ON
GND
FAULT
MAX1693
MAX1694
MAX1693
MAX1694
8
7
6
µMAX
________________________________________________________________
Maxim Integrated Products
1
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