LT1246/LT1247

6

CC

HARA TERISTICS

A

TYPICALPERFOR

CE

Timing Resistor vs

Oscillator Frequency

current sense comparator. The trip point of the compara-

tor is set by, and is proportional to, the output voltage of

the Error Amplifier.

The rise time of the oscillator waveform is set by the RC

the output deadtime, is set by a combination of the RC time

constant and the oscillator sink current (8.2mA typ.).

COMP (Pin 1): Compensation Pin. This pin is the output of

the Error Amplifier and is made available for loop compen-

sation. It can also be used to adjust the maximum value of

the current sense clamp voltage to less than 1V. This pin

can source a minimum of 0.5mA (0.8mA typ.) and sink a

minimum of 2mA (4mA typ.)

FB (Pin 2): Voltage Feedback. This pin is the inverting

input of the Error Amplifier. The output voltage is normally

fed back to this pin through a resistive divider. The

noninverting input of the Error Amplifier is internally

committed to a 2.5V reference point.

PI

FU C

S

TI

OSCILLATOR FREQUENCY (Hz)

10k

1

10

100

100k

1M

LT1246 • TPC19

5nF

2nF

100pF

1nF

500pF

200pF

TIME 50ns/DIV

1246/7 G20

TIME 50ns/DIV

1246/7 G21

Output Rise and Fall Time

Current Sense Delay

Output Cross-Conduction

TIME 50ns/DIV

1246/7 G22

Output Deadtime vs

Oscillator Frequency

OSCILLATOR FREQUENCY (kHz)

0

0

10

20

30

40

50

60

100

1000

LT1246 • TPC18*

5nF

2nF

1nF

100pF

500pF