The LM3940 is a 1-A low-dropout regulator designed to provide 3.3 V from a 5-V supply.
The LM3940 is ideally suited for systems which contain both 5-V and 3.3-V logic, with prime power provided from a 5-V bus.
Because the LM3940 is a true low dropout regulator, it can hold its 3.3-V output in regulation with input voltages as low as 4.5 V.
The TO-220 package of the LM3940 means that in most applications the full 1 A of load current can be delivered without using an additional heat sink.
The surface mount DDPAK/TO-263 package uses minimum board space, and gives excellent power dissipation capability when soldered to a copper plane on the PC board.
- Input Voltage Range: 4.5 V to 5.5 V
- Output Voltage Specified over Temperature
- Excellent Load Regulation
- Specified 1-A Output Current
- Requires only One External Component
- Built-in Protection against Excess Temperature
- Short-Circuit Protected
|Output options||Fixed Output|
|Iout (Max) (A)||1|
|Vin (Max) (V)||5.5|
|Vin (Min) (V)||4.5|
|Vout (Max) (V)||3.3|
|Vout (Min) (V)||3.3|
|Fixed output options (V)||3.3|
|Package Group||DDPAK/TO-263 | 3, TO-220 | 3, SOT-223 | 4|
|Regulated outputs (#)||1|
|Operating temperature range ( C )||-40 to 125|
|Thermal resistance θJA (°C/W)||23|
|Rating||See Data Sheet|
|PSRR @ 100 KHz (dB)||32|
|Dropout voltage (Vdo) (Typ) (mV)||310|
|Iq (Typ) (mA)||0.11|
|Package size: mm2:W x L (PKG)||3DDPAK/TO-263: 155 mm2: 15.24 x 10.16 (DDPAK/TO-263 | 3)|
|3TO-220: 47 mm2: 4.58 x 10.16 (TO-220 | 3)|
|4SOT-223: 46 mm2: 7 x 6.5 (SOT-223 | 4)|
* product image for illustration purposes only. actual product may vary.