MAX4944, MAX4944L：Overvoltage-Protection Controllers with Internal FET

Provide Input Voltage Protection Up to +28V without Requiring an External nFET

The MAX4943–MAX4946/MAX4949 family of overvoltage-protection devices feature a low 80mΩ (typ) RON internal FET and protect low-voltage systems against voltage faults up to +28V. These devices also drive an optional external pFET to protect down to -28V when connected to a load with reverse current protection. When the input voltage exceeds the overvoltage threshold, the internal FET is turned off to prevent damage to the protected components. All switches feature a minimum 1.2A current-limit protection. During a short-circuit occurrence, the MAX4944B and MAX4945B place the switch in a latchoff state where the switch turns off and remains off. For the autoretry devices, the switch turns off and continuously checks after a 15ms (typ) retry time. The overvoltage thresholds (OVLO) are preset to 7.4V, 6.35V, 5.8V, 4.56V, or 8.9V. The undervoltage-lockout (UVLO) thresholds are preset to 2.45V and 4.15V. When the input voltage drops below the undervoltagelockout (UVLO) threshold, the devices enter a lowcurrent standby mode. (See the Ordering Information/Selector Guide in the full data sheet for more details on UVLO/OVLO). All devices are offered in a small, 8-pin µDFN (2mm x 2mm) package and are specified for operation over the -40°C to +85°C temperature range.

Key Features

Input Voltage Protection Up to +28V
Integrated nFET Switch
Preset Overvoltage Protection Trip Level
- 7.40V (MAX4943)
- 6.35V (MAX4944_)
- 5.80V (MAX4945_)
- 4.56V (MAX4946)
- 8.90V (MAX4949)
Low-Current Undervoltage-Lockout Mode
Short-Circuit Protection (Latchoff/Autoretry)
Internal 15ms (typ) Startup Delay and Retry Times
Input Voltage Power-Good Logic Output
Thermal-Shutdown Protection
Small, 8-Pin (2mm x 2mm) µDFN Package

MAX4943, MAX4944, MAX4944L, MAX4945, MAX4946, MAX4949: Typical Operating Circuit

Applications/Uses

Cell Phones
Digital Still Cameras
MP3 Players
PDAs and Palmtop Devices

DataSheet

title	Download file
MAX4943-MAX4949 Data Sheet	MAX4943-MAX4949.pdf

Parametrics

Part Number	Channels	V_IN (V)	V_IN (V)	Over Voltage Trip Level (V)	Under Voltage Lockout (V)	Over Volt. Flag	t_GATE (On) (ms)	t_GATE (Off) (µs)	Package/Pins	Budgetary Price
Part Number	Channels	min	max	Over Voltage Trip Level (V)	Under Voltage Lockout (V)	Over Volt. Flag	t_GATE (On) (ms)	t_GATE (Off) (µs)	Package/Pins	See Notes
MAX4944	1	2.2	28	6.35	4.15	Open-Drain	30.2	2	µDFN/8	$2.75 @1k
MAX4945				5.8	4.15				µDFN/8	$2.76 @1k
MAX4946				4.56	2.45				µDFN/8	-
MAX4949				8.9	2.45				µDFN/8	-

Ordering Information

Part Number	Status	Package	Temp	RoHS
MAX4944BELA+T	No Longer Available	uDFN;	-40°C to +85°C	See data sheet
MAX4944ELA+	Active	µDFN,;8 pin;4.2 mm²	-40°C to +85°C	Lead Free
MAX4944ELA+T	Active	µDFN,;8 pin;4.2 mm²	-40°C to +85°C	Lead Free
MAX4944LELA+	Active	µDFN,;8 pin;4.2 mm²	-40°C to +85°C	Lead Free
MAX4944LELA+T	No Longer Available	µDFN,;8 pin;4.2 mm²	-40°C to +85°C	Lead Free

MAX4943-MAX4949.pdf MAX4949

MAX4943-MAX4949_cn.pdf MAX4949

MAX4943-MAX4949_cn.pdf MAX4943