UCC2941-3, UCC2941-5, UCC2941-ADJ, UCC3941-3, UCC3941-5, UCC3941-ADJ

1V SYNCHRONOUS BOOST CONVERTER

SLUS242B – JANUARY 1999 – REVISED JUNE 2001

4

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detailed description (continued)

needs a name (SW)

The SW pin inductor is connected between this node and VIN. The VGD (gate drive supply) flyback diode is

also connected to this pin. When servicing the 3.3-V supply, this pin goes low charging the inductor, then shut

off, dumping the energy through the synchronous rectifier to the output. When servicing the VGD supply, the

internal synchronous rectifier stays off, and the energy is diverted to VGD through the flyback diode. During

discontinuous portions of the inductor current a MOSFET resistively connects VIN to SW damping excess

circulating energy to eliminate undesired high frequency ringing.

gate drive supply (VGD)

The VGD pin is coarsely regulated around 9 V, and is primarily used for the gate drive supply for the power

switches in the IC. This pin can be loaded with up to 10 mA as long as it does not present a load at voltages

below 2 V. This ensures proper startup of the IC. The VGD supply can go as low as 7.5 V without interfering

with the servicing of the 3.3-V output. Below 7.5 V, VGD has the highest priority, although in practice the voltage

should not decay to that level if the output capacitor is sized properly.

output voltage (VOUT)

Main output voltage (3.3 V, 5 V, or adjustable) which has highest priority in the multiplexing scheme, as long

as VGD is above the critical level of 7.5 V. Loads over 150 mA are achievable at an input voltage of 1-V. This

output starts up with 1-V input at full load.

Input voltage VIN, PLIM

–0.3 V to 10 V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Voltage range, VGD, SW

–0.3 V to 15 V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Voltage range, SD

–0.3 V to VIN

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Output voltage range, VOUT

–0.3 V to 10 V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

–55

_C to 150_C

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

–65

_C to 150_C

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Lead temperature soldering 1,6 mm (1/16 inch) from case for 10 seconds

300

_C

. . . . . . . . . . . . . . . . . . . . . . .

CDM 1 kV

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

† Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and

functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not

implied. Exposure to absolute–maximum–rated conditions for extended periods may affect device reliability. Currents are positive into, negative

out of the specified terminal.

DISSIPATION RATING TABLE

PACKAGE

TA ≤ 25_C

POWER RATING

DERATING FACTOR

ABOVE TA = 25_C

TA = 85_C

POWER RATING

D

760 mW

6.1 mW/

_C

390 mW

N

980 mW

7.9 mW/

_C

510 mW

recommended operating conditions

MIN

MAX

UNIT

Input voltage

0.8

5.0

V

Output voltage

1.8

5.5

V

Output current

0

200

mA