MAX5943 Datasheet, PDF (1/20 Pages) Maxim Integrated Products – FireWire Current Limiter and Low-Drop ORing Switch Controller

19-3378; Rev 0; 8/04
FireWire Current Limiter and Low-Drop
ORing Switch Controller
General Description
The MAX5943 is a fully integrated power-management
IC for FireWire^® applications. This device controls two
external power n-channel MOSFETs to regulate current
from the input power supply to the load and performs
low-voltage-drop, power-supply ORing. The MAX5943
operates over a 7.5V to 37V input range and provides
inrush and output current limit in addition to a diode
ORing function suitable for FireWire applications.
The MAX5943 allows the safe insertion and removal of
FireWire peripherals into a live FireWire port by providing
inrush current control and an output current-limiting func-
tion. The ORing feature provides a very efficient way to
protect the FireWire port when connected to another
FireWire peripheral that sources a higher voltage. By turn-
ing off both external MOSFETS, the MAX5943 provides a
true bidirectional load disconnect. A low-current shut-
down mode disables the MAX5943, resulting in less than
10µA supply current. A pin-selectable input allows
latched or autoretry fault management after a fault.
The MAX5943A features a current-limit function that
actively limits the current drawn by the load with a pro-
grammable timeout. The MAX5943B–MAX5943E do not
actively limit the load current but provide a circuit-breaker
function. See the Selector Guide for the default and pro-
grammable circuit-breaker timeouts.
The MAX5943 operates over the -40°C to +85°C extended
temperature range and is available in a 16-pin QSOP
package.
Applications
FireWire Desktop/Notebook Port
FireWire Peripheral Device Current Limit
FireWire Hub
Hot Swap
Features
♦ Provides Safe Hot Swap for 7.5V to 37V Power
Supplies
♦ Low-Drop Power ORing with Ultra-Fast Turn-Off
♦ Programmable Active Current Limit (MAX5943A)
♦ Programmable Circuit Breaker
(MAX5943B–MAX5943E)
♦ ±5% Current-Limit Sensing Accuracy
♦ Programmable Current-Limit/Circuit-Breaker
Timeout
♦ Fast Current-Limit Response to Output Short-
Circuit Conditions (MAX5943A)
♦ Drives External N-Channel Power MOSFETs
♦ Overcurrent Fault Status Output
♦ Latched or Autoretry Overcurrent Fault
Management
♦ 10µA Shutdown Current
♦ ON/OFF Control Allows Undervoltage Lockout
Programming
♦ Fast Load Disconnect Control Through ON Input
Ordering Information
PART
MAX5943AEEE
MAX5943BEEE
MAX5943CEEE
MAX5943DEEE
MAX5943EEEE
TEMP RANGE PIN-PACKAGE
-40°C to +85°C 16 QSOP
-40°C to +85°C 16 QSOP
-40°C to +85°C 16 QSOP
-40°C to +85°C 16 QSOP
-40°C to +85°C 16 QSOP
Pin Configuration
Typical Operating Circuit and Selector Guide appear at end
of data sheet.
FireWire is a registered trademark of Apple Computers, Inc.
TOP VIEW
ON ₁
FAULT 2
TIM 3
ILIM 4
LATCH 5
OR_ADJ 6
N.C. 7
ONQ1 8
MAX5943
QSOP
16 IN
15 SENSE
14 GATE1
13 N.C.
12 GATE2
11 OUT
10 N.C.
9 GND
________________________________________________________________ Maxim Integrated Products 1
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