3

LT1776

ELECTRICAL CHARACTERISTICS

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Timing

f

Switching Frequency

180

200

220

kHz

q

170

230

kHz

Maximum Switch Duty Cycle

q

85

90

%

Minimum Switch On Time

300

ns

Boost Operation

1.35

V

dV/dt Below Threshold

0.2

V/ns

dV/dt Above Threshold

1.6

V/ns

Sync Function

Minimum Sync Amplitude

q

1.5

2.2

V

Synchronization Range

(Note 6)

q

250

400

kHz

SYNC Pin Input R

40

k

Ω

SHDN Pin Function

Shutdown Mode Threshold

0.5

V

q

0.2

0.8

V

Upper Lockout Threshold

Switching Action On

1.260

V

Lower Lockout Threshold

Switching Action Off

1.245

V

Shutdown Pin Current

12

20

µA

2.5

10

µA

Note 1: Absolute Maximum Ratings are those values beyond which the life

of a device may be impaired.

Note 3: Switch current limit is DC trimmed and tested in production.

Inductor dl/dt rate will cause a somewhat higher current limit in actual

application.

Note 4: Minimum switch on time is production tested with a 39

Ω resistive

load to ground.

on maximum output current and switching frequency. See Applications

section for more information.

Note 6: Internal oscillator is guaranteed to sync up to 400kHz. However,

thermal constraints and/or controllability issues may place a lower limit on

switching frequency in actual usage. See Applications section for more

information.