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MAX5943DEEE+

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P20
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 FireWire/IEEE 1394™ protective circuit
(Figure 12) is UL
®
recognized.
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
o Provides Safe Hot Swap for 7.5V to 37V Power
Supplies
o UL-Recognized FireWire/IEEE 1394 Protective
Circuit
o Low-Drop Power ORing with Ultra-Fast Turn-Off
o Programmable Active Current Limit (MAX5943A)
o Programmable Circuit Breaker
(MAX5943B–MAX5943E)
o ±5% Current-Limit Sensing Accuracy
o Programmable Current-Limit/Circuit-Breaker
Timeout
o Fast Current-Limit Response to Output Short-
Circuit Conditions (MAX5943A)
o Drives External N-Channel Power MOSFETs
o Overcurrent Fault Status Output
o Latched or Autoretry Overcurrent Fault
Management
o 10µA Shutdown Current
o ON/OFF Control Allows Undervoltage Lockout
Programming
o 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 2; 10/07
For pricing, delivery, and ordering information, please contact Maxim 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.
IEEE 1394 is a trademark of the Institute of Electrical and
Electronics Engineers trademark.
UL is a registered trademark of Underwriters Laboratories, 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
MAX5943
FireWire Current Limiter and Low-Drop
ORing Switch Controller
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
IN
= 7.5V to 37V, GND = 0V, and T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
IN
= 12V, T
A
= +25°C.)
(Note 1)
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.
(Voltages referenced to GND, unless otherwise noted.)
IN ............................................................................-0.3V to +80V
OUT ........................................................................-0.3V to +80V
SENSE to IN..............................................................-1V to +0.3V
GATE1 to SENSE......................................................-0.3V to +8V
GATE2 to OUT (internally clamped).........................-0.3V to +8V
FAULT.....................................................................-0.3V to +85V
ON, TIM, ILIM, LATCH, OR_ADJ, ONQ1 ..........-0.3V to (IN + 0.3V)
Continuous Power Dissipation (T
A
= +70°C)
16-Pin QSOP (derate 8.3mW/°C above +70°C)...........667mW
Operating Temperature Range ...........................-40°C to +85°C
Maximum Junction Temperature .....................................+150°C
Storage Temperature Range .............................-60°C to +150°C
ESD Rating (Human Body Model)......................................2000V
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
SUPPLIES
Supply Voltage Range V
IN
7.5 37 V
Supply Current I
IN
V
ON
= 3V, no load 1.3 2.3 mA
Shutdown Current I
SD
V
ON
= 0.4V 5 10 µA
IN Default Undervoltage Lockout V
UVLO
V
IN
rising, ON = IN 6.2 6.5 6.8 V
IN Default Undervoltage Lockout
Hysteresis
0.35 V
ON Undervoltage Lockout
Threshold
V
ON_REF
V
ON
rising 1.20 1.24 1.275 V
ON Undervoltage Lockout
Threshold Hysteresis
70 mV
ON Input Bias Current I
ON
1µA
GATE2 (current-limit/circuit-breaker control)
GATE2 Pullup Current I
G2U
(Note 2) 36 45 54 µA
7.5V ≤ V
IN
≤ 8V 4.25 5.5 6.5
GATE2 High Voltage V
G2
V
GATE2
- V
OUT
8V ≤ V
IN
≤ 37V 4.5 5.5 6.5
V
ILIM = GND 47.5 50 52.5
ILIM = floating 37 39 41
Current-Limit/Circuit-Breaker
Threshold Voltage
V
TH
V
IN
- V
SENSE
ILIM = IN 55 58.5 61
mV
ILIM = GND 70 75 80
ILIM = floating 54 59 64
Fast Pulldown Current-Limit
Threshold Voltage (MAX5943A)
V
THF
V
IN
- V
SENSE
(Note 3)
ILIM = IN 83 88 93
mV
GATE2 Pulldown Current
(MAX5943A)
I
G2D
V
TH
< (V
IN
- V
SENSE)
< V
THF
,
t < t
ILIM
335 435 535 µA
GATE2 Fast Pulldown Current
(MAX5943A)
I
G2DF
(V
IN
- V
SENSE)
> V
THF
, V
GATE2
= V
OUT
+
4.5V
80 125 200 mA
GATE2 Peak Pulldown Current
(MAX5943A)
I
G2DP
(V
IN
- V
SENSE)
= 1V 1.0 A
MAX5943
FireWire Current Limiter and Low-Drop
ORing Switch Controller
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= 7.5V to 37V, GND = 0V, and T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
IN
= 12V, T
A
= +25°C.)
(Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
GATE2 Pulldown Current During
Any GATE2 Turn-Off Condition
I
G2OFF
V
GATE2
= V
OUT
+ 4.5V (Note 4) 80 125 200 mA
GATE1 (ORing control)
OR_ADJ = GND 3 5 7
OR_ADJ = floating 5.5 7.5 9.5
ORing Switch Turn-On Current
Threshold Voltage
V
OR
(V
IN
- V
SENSE
) rising
OR_ADJ = IN 8.5 10.5 12.8
mV
ORing Switch Turn-On Current
Threshold Voltage Hysteresis
(V
IN
-
V
SENSE
) falling 0.5 mV
GATE1 Pullup Current I
G1U
(Note 5) 36 45 54 µA
7.5V ≤ V
IN
≤ 8V 4.25 5.5 6.5
GATE1 High Voltage V
G1
V
GATE1
- V
SENSE
8V ≤ V
IN
≤ 37V 4.5 5.5 6.5
V
GATE1 Turn-Off Switch On-
Resistance
R
G1
Measured between GATE1 and SENSE
when (V
IN
- V
SENSE
) < V
OR
23Ω
LOGIC INPUTS
I
IX
Current into or out of input for tri-state logic
condition
-3 +3
I
IXL
Current out of input for logic low 20
ILIM, OR_ADJ Input-Logic
Tristate Current Tolerance
(Note 6)
I
IH
Current into input for logic high 20
µA
V
IL
V
ON
> V
ON_REF
0.7 V
LATCH, ONQ1 Input-Logic Low
Voltage
I
IL
LATCH, ONQ1 = GND, V
ON
> V
ON_REF
1µA
LATCH, ONQ1 Input-Logic High
Voltage
V
IH
V
ON
> V
ON_REF
1.8 V
LATCH, ONQ1 Input Current I
IH
All voltages = V
IN
, V
ON
> V
ON_REF
1µA
TIM, ILIM, LATCH, OR_ADJ,
OUT, ONQ1 Shutdown Mode
Input Current
I
IH_SD
All voltages = V
IN
, V
ON
≤ 0.4V 1 µA
FAULT Output Low Voltage V
OL
Low-impedance state, I
FAULT
= 5mA 0.12 0.25 V
FAULT Output High Leakage
Current
I
OH
High-impedance state, V
FAULT
= 37V 1 µA
TIMING
TIM = IN 1.78 2.02 2.26 ms
R
TIM
= 4kΩ 0.87 1.04 1.21 ms
R
TIM
= 50kΩ 9.2 11.05 12.9 ms
Current-Limit Timeout
(MAX5943A)
t
ILIM
Current-limit mode
(Note 7)
TIM = floating 120 175 225 ms
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P20

MAX5943DEEE+

Mfr. #:
Buy MAX5943DEEE+
Manufacturer:
Maxim Integrated
Description:
Hot Swap Voltage Controllers FireWire Current Limite
Lifecycle:
New from this manufacturer.
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