LTC3443

5

sn3443 3443fs

TYPICAL PERFOR A CE CHARACTERISTICS

Minimum Start Voltage

TEMPERATURE (°C)

–50

0.05

0.07

0.09

0.11

–25

5

35

65

3443 G16

95

0.13

0.15

125

SWITCHES A AND D

TEMPERATURE (°C)

–55

2.10

2.15

2.20

2.25

2.30

–25

5

35

65

3443 G17

95

125

PI FU CTIO S

SHDN/SS (Pin 1): Combined Soft-Start and Shutdown.

Applied voltage < 0.4V shuts down the IC. Tie to >1.4V to

enable the IC and >2.4V to ensure the error amp is not

clamped from soft-start. An RC from the shutdown com-

mand signal to this pin will provide a soft-start function by

GND (Pin 2): Signal Ground for the IC.

PGND (Pins 3, 6, 13 Exposed Pad): Power Ground for the

Internal NMOS Power Switches. The exposed pad must be

soldered to PCB ground for optimal thermal performance.

SW1 (Pin 4): Switch pin where the internal switches A and

B are connected. Connect inductor from SW1 to SW2. An

optional Schottky diode can be connected from this SW1

to ground. Minimize trace length to keep EMI down.

SW2 (Pin 5): Switch pin where the internal switches C

and D are connected. An optional Schottky diode can be

MODE/SYNC (Pin 7): Burst Mode Select and Oscillator

Synchronization.

MODE/SYNC = High: Enable Burst Mode Operation.

During the period where the IC is supplying energy to

the output, the inductor peak inductor current will reach

0.8A and return to zero current on each cycle. In Burst

Mode operation the operation is variable frequency,

which provides a significant efficiency improvement at

light loads. The Burst Mode operation will continue until

the pin is driven low.

TEMPERATURE (°C)

–55

0.05

0.07

0.09

0.11

0.13

0.15

–25

535

65

3443 G15

95

125

SWITCHES B AND C

Error Amp Sink Current

TEMPERATURE (°C)

–55

200

250

300

350

400

–25

5

35

65

3443 G12

95

125

Output Frequency

Current Limit

TEMPERATURE (°C)

–55

0.50

0.55

0.60

0.65

0.70

–25

5

35

65

3443 G13

95

125

TEMPERATURE (°C)

–55

2.8

3.0

3.2

3.4

–25

5

35

65

3443 G14

95

125