MAX5944：Dual FireWire Current Limiter and Low-Drop ORing Switch Controller

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-voltagedrop power-supply ORing. The MAX5944 operates over the 7.5V to 37V input range and provides inrush and output current limit in addition to diode ORing functions suitable 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 functions. 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 protect 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.

Key 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

MAX5944: Typical Operating Circuit

Applications/Uses

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

DataSheet

title	Download file
MAX5944 Data Sheet	MAX5944.pdf

Parametrics

Part Number	V_IN (V)	V_IN (V)	Circuit Breaker/ Current Limit	Fault Condition Control	Channels	Positive/Negative Rail	Features	Package/Pins	Budgetary Price
Part Number	min	max	Circuit Breaker/ Current Limit	Fault Condition Control	Channels	Positive/Negative Rail	Features	Package/Pins	See Notes
MAX5944	7.5	37	Current Limit	Periodic Retry	2	Positive	Dual Firewire Controller	SOIC(N)/16	$3.38 @1k

Part Number	Reverse Current Protect.	Under Voltage Protect	Charge Pump Cap.	Soft Start	Enable	Fault Indicator	Package/Pins	Oper. Temp. (°C)	Budgetary Price
Part Number	Reverse Current Protect.	Under Voltage Protect	Charge Pump Cap.	Soft Start	Enable	Fault Indicator	Package/Pins	Oper. Temp. (°C)	See Notes
MAX5944	Yes	Yes	No	Yes	Yes	Yes	SOIC(N)/16	-40 to +85	$3.38 @1k

Design kits & evaluation modules

MAX5944EVKIT

Quality and Environmental Data

MAX5944.pdf

Ordering Information

Part Number	Status	Recommended Replacement	Package	Temp	RoHS
MAX5944ESE	No Longer Available	MAX5944ESE+	SOIC(N),;16 pin;62 mm²	-40°C to +85°C	No
MAX5944ESE+	Active		SOIC(N),;16 pin;62 mm²	-40°C to +85°C	Lead Free
MAX5944ESE+T	Active		SOIC(N),;16 pin;62 mm²	-40°C to +85°C	Lead Free
MAX5944ESE-T	No Longer Available	MAX5944ESE+T	N.SO;16 pin	-40°C to +85°C	See data sheet