MAX5944 Datasheet, PDF (1/15 Pages) Maxim Integrated Products – Dual FireWire Current Limiter and Low-Drop ORing

19-3426; Rev 0; 10/04
Dual FireWire Current Limiter and Low-Drop
ORing Switch Controller
General Description
The MAX5944 is a dual, current limiter/low-drop ORing,
switch controller power-management IC for FireWire^®
applications. Each independent channel controls two
external power MOSFETs to regulate current from the
input power supply to the load and performs low-voltage-
drop power-supply ORing. The MAX5944 operates over
the 7.5V to 37V input range and provides inrush and out-
put current limit in addition to diode ORing functions suit-
able for FireWire applications.
The MAX5944 allows the safe insertion and removal of
FireWire peripherals into a live FireWire port by providing
inrush current control and output current-limiting func-
tions. The MAX5944 features a current-limit function that
actively limits the current drawn by the load with a 2ms
timeout. Its autoretry function then automatically restarts
after the 259ms autoretry delay time.
The ORing feature provides a very efficient way to pro-
tect the FireWire port when connected to another
FireWire peripheral that sources a higher voltage. By
turning off the external MOSFETS, the MAX5944 provides
a true bidirectional load disconnect. Each channel has
an independent ON/OFF control that results in less than
10µA supply current per channel.
The MAX5944 operates over the -40°C to +85°C
extended temperature range and is available in a
16-pin SO package.
Features
♦ Provides Safe Hot-Swap for 7.5V to 37V Power
Supplies
♦ Dual-Channel Hot-Swap
♦ Low-Drop Power ORing with Ultra-Fast Turn-Off
♦ Active Current Limit
♦ ±5% Current-Limit Sensing Accuracy
♦ 2ms Current-Limit Timeout
♦ Fast Current-Limit Response to Output
Short-Circuit Conditions
♦ Drives External n-Channel Power MOSFETs
♦ Independent Overcurrent Fault Status Outputs
♦ 259ms Autoretry Period
♦ 10µA (Per Channel) Shutdown Current
♦ Independent ON/OFF Control Allows
Undervoltage Lockout Programming
♦ Fast Load Disconnect Control Through
ON/OFF Inputs
♦ Bidirectional Load Disconnect
♦ Power Routing from One Port to Another
Applications
FireWire Desktop/Notebook Port
FireWire Peripheral Device Current Limit
FireWire Hub
Hot Swap
PART
MAX5944ESE
Ordering Information
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
16 SO
Pin Configuration
Typical Operating Circuit appears at end of data sheet.
FireWire is a registered trademark of Apple Computer, Inc.
TOP VIEW
INA ₁
ONA 2
FAULTA 3
ONQ1 4
OUTB 5
GATE2B 6
GATE1B 7
SENSEB 8
MAX5944
SO
16 SENSEA
15 GATE1A
14 GATE2A
13 OUTA
12 GND
11 FAULTB
10 ONB
9 INB
________________________________________________________________ Maxim Integrated Products 1
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