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 heatsink.
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.
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|Part number||Order||Output options||Iout (Max) (A)||Vin (Max) (V)||Vin (Min) (V)||Vout (Max) (V)||Vout (Min) (V)||Fixed output options (V)||Package Group||Features||Regulated outputs (#)||Operating temperature range (C)||Thermal resistance θJA (°C/W)||Noise (uVrms)||Approx. price (US$)||Rating||PSRR @ 100 KHz (dB)||Accuracy (%)||Dropout voltage (Vdo) (Typ) (mV)||Iq (Typ) (mA)||Package size: mm2:W x L (PKG)|
DDPAK/TO-263 | 3
SOT-223 | 4
TO-220 | 3
|1||-40 to 125||23||150||0.55 | 1ku||Catalog||32||2.5||310||0.11||
3DDPAK/TO-263: 155 mm2: 15.24 x 10.16 (DDPAK/TO-263 | 3)
4SOT-223: 46 mm2: 7 x 6.5 (SOT-223 | 4)
3TO-220: 47 mm2: 4.58 x 10.16 (TO-220 | 3)
DDPAK/TO-263 | 5
SOT-223 | 5
|1||-40 to 125||40||100||1.41 | 1ku||Catalog||2||380||6||
5DDPAK/TO-263: 155 mm2: 15.24 x 10.16 (DDPAK/TO-263 | 5)
5SOT-223: 45 mm2: 6.96 x 6.5 (SOT-223 | 5)