LTC2927

4

2927fb

PIN FUNCTIONS

0

0.0

0.2

0.4

0.6

0.8

1.0

1234

2927 G0

5

2.5

3.0

3.5

4.0

4.5

6.0

5.5

5.0

10

20

30

40

50

60

2927 G07

1

0

1

2

3

4

5

234

2927 G0

5

ERROR =

•

0.8V

–1

is from 2.9V to 5.5V. An undervoltage lockout asserts SDO

0.1μF capacitor.

SDO (Pin 2/Pin 7): Slave Supply Shutdown Output. SDO

is an open-drain output that holds the shutdown (RUN/SS)

2.5V, and the ON pin is pulled above 1.23V, or RAMP is

above 200mV. SDO is pulled low again when both RAMP

< 200mV and ON < 1.23V. If the slave supply is capable

of operating with an input supply that is lower than the

LTC2927’s minimum operating voltage of 2.9V, the SDO

pin can be used to hold off the slave supply. Tie the SDO

pin to GND if unused.

FB (Pin 3/Pin 6): Feedback Control Output. FB pulls up

on the feedback node of the slave supply. Tracking is

achieved by mirroring the current from TRACK into FB.

A resistive divider connecting RAMPBUF and TRACK will

force the output voltage of the slave supply to track RAMP.

To prevent damage to the slave supply, the FB pin will not

force the slave’s feedback node above 2.3V. In addition,

the LTC2927 will not actively sink current from this node,

even when it is unpowered.

TSOT/DFN Packages

TYPICAL PERFOR A CE CHARACTERISTICS

TEMPERATURE (°C)

–50

10

18

16

14

12

20

22

24

26

28

–25

0

25

50

2927 G05

75

100

TEMPERATURE (°C)

–50

1.210

1.215

1.220

1.225

1.230

1.235

1.240

–25

0

25

50

2927 G04

75

100

TEMPERATURE (°C)

–50

40

45

50

55

60

65

70

–25

0

25

50

2927 G06

75

100