MAX5943 FireWire Current Limiter and Low-Drop ORing Switch Controller

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 of the full data sheet) 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 function. 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 turning off both external MOSFETS, the MAX5943 provides a true bidirectional load disconnect. A low-current shutdown 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 programmable timeout. The MAX5943B–MAX5943E do not actively limit the load current but provide a circuit-breaker function. See the Selector Guide in the full data sheet for the default and programmable 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.

Key Features

Applications/Uses

Provides Safe Hot Swap for 7.5V to 37V Power Supplies
UL-Recognized FireWire/IEEE 1394 Protective Circuit
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

	FireWire® Desktop/Notebook Port
	FireWire® Hub
	FireWire® Peripheral Device Current Limit
	Hot Swap

Key Specifications: Hot Swap Controllers

Part Number

Min. V_IN (V)

Max. V_IN (V)

Low Voltage

High Voltage

Voltage Polarity

Type

Fault Condition Control

Number of Channels

Features

RoHS Available

Package

Smallest Available Package (max w/pins) (mm²)

Operating Temp. Range (°C)

Price^**

MAX5943

7.5

Yes

Positive

Positive, Low-Voltage

Latched Off or Periodic Retry

•	1A Peak Short-Circuit Gate Pulldown Current

•	Adjustable auto-retry duty cycle and over-current timeout

•	Drives external Dual MOSFET for ORing Function

•	Fault Status Output Active Low

•	In-Rush Current and Short Circuit Protection

•	Single Firewire Controller

Yes

QSOP/16

-40 to +85

$1.06 @ 1k

See All Hot Swap Controllers (44)

Key Specifications: ORing MOSFET Controllers

Part Number

Reverse Current Protection

Under-Voltage Protection

Charge-Pump Capacitor

Soft Start

Enable

Fault Indicator

EV-Kit

RoHS Available

Package

Smallest Available Package (max w/pins) (mm²)

Operating Temp. Range (°C)

Price^**

MAX5943

Yes

QSOP/16

-40 to +85

$1.06 @ 1k

See All ORing MOSFET Controllers (5)

Notes:
^**This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

Ordering Information

Notes:

Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.
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Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt. More: SeeFull Data Sheet or Part Naming Conventions.
* Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.

Devices: 1-20 of 20

MAX5943

Free
Sample

Buy

Package:	TYPE PINS FOOTPRINT
	DRAWING CODE/VAR *

Temp

RoHS/Lead-Free?
Materials Analysis

MAX5943AEEE

QSOP;16 pin;31 mm²
Dwg: 21-0055G (PDF)
Use pkgcode/variation: E16-5*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX5943AEEE+T

QSOP;16 pin;31 mm²
Dwg: 21-0055G (PDF)
Use pkgcode/variation: E16+5*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX5943BEEE+

QSOP;16 pin;31 mm²
Dwg: 21-0055G (PDF)
Use pkgcode/variation: E16+5*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX5943BEEE+T

-40°C to +85°C

See data sheet

MAX5943CEEE+

QSOP;16 pin;31 mm²
Dwg: 21-0055G (PDF)
Use pkgcode/variation: E16+5*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX5943CEEE+T

-40°C to +85°C

See data sheet

MAX5943DEEE+

QSOP;16 pin;31 mm²
Dwg: 21-0055G (PDF)
Use pkgcode/variation: E16+5*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX5943DEEE+T

-40°C to +85°C

See data sheet

MAX5943EEEE+

QSOP;16 pin;31 mm²
Dwg: 21-0055G (PDF)
Use pkgcode/variation: E16+5*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX5943AEEE+

QSOP;16 pin;31 mm²
Dwg: 21-0055G (PDF)
Use pkgcode/variation: E16+5*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX5943EEEE-T

-40°C to +85°C

See data sheet

MAX5943AEEE-T

QSOP;16 pin;31 mm²
Dwg: 21-0055G (PDF)
Use pkgcode/variation: E16-5*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX5943BEEE

QSOP;16 pin;31 mm²
Dwg: 21-0055G (PDF)
Use pkgcode/variation: E16-5*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX5943BEEE-T

-40°C to +85°C

See data sheet

MAX5943CEEE

QSOP;16 pin;31 mm²
Dwg: 21-0055G (PDF)
Use pkgcode/variation: E16-5*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX5943CEEE-T

-40°C to +85°C

See data sheet

MAX5943DEEE

QSOP;16 pin;31 mm²
Dwg: 21-0055G (PDF)
Use pkgcode/variation: E16-5*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX5943DEEE-T

-40°C to +85°C

See data sheet

MAX5943EEEE

QSOP;16 pin;31 mm²
Dwg: 21-0055G (PDF)
Use pkgcode/variation: E16-5*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX5943EEEE+T

-40°C to +85°C

See data sheet