Rainbow Electronics MAX5943 - Manual

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
MAX5943
FireWire Current Limiter and Low-Drop
ORing Switch Controller
________________________________________________________________ Maxim Integrated Products 1
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
ON IN
SENSE
GATE1
N.C.
GATE2
OUT
N.C.
GND
TOP VIEW
MAX5943
QSOP
FAULT
TIM
OR_ADJ
ILIM
LATCH
N.C.
ONQ1
Pin Configuration
Ordering Information
19-3378; Rev 0; 8/04
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.
Typical Operating Circuit and Selector Guide appear at end
of data sheet.
FireWire is a registered trademark of Apple Computers, Inc.
PART TEMP RANGE PIN-PACKAGE
MAX5943AEEE -40
°
C to +85
°
C 16 QSOP
MAX5943BEEE -40
°
C to +85
°
C 16 QSOP
MAX5943CEEE -40
°
C to +85
°
C 16 QSOP
MAX5943DEEE -40
°
C to +85
°
C 16 QSOP
MAX5943EEEE -40
°
C to +85
°
C 16 QSOP