ABSOLUTE MAXIMUM RATINGS:

PARAMETER

SYMBOL

VALUE

UNIT

DC Supply Voltage

+20

V

Any Input Voltage

V

Operating Temperature

0 to +80

˚C

Storage Temperature

-65 to +150

˚C

DC ELECTRICAL CHARACTERISTICS:

PARAMETER

SYMBOL

MIN

TYPE

MAX

UNIT

CONDITION

Supply Voltage

+12

–

+18

V

-

Supply Current

–

1.0

1.4

mA

output off

Input Voltages:

MODE LO

0

–

V

-

MODE HI

–

V

-

SYNC LO

0

–

V

-

SYNC HI

–

V

-

SENS LO

0

–

V

-

SENS HI

–

V

-

EXT LO

0

–

V

-

EXT HI

–

V

-

Input Current:

SYNC, SENS, EXT HI

–

–

110

µA

With Series 1.5M

Ω

Resistor to

115VAC Line

SYNC, SENS, EXT LO

–

–

100

nA

-

TRIG HI Voltage

–

–

V

-

TRIG LO Voltage

–

–

V

TRIG Sink Current

25

–

–

mA

TIMING CHARACTERISTICS (See Figures 2 and 3):

All timings are based on fs = 60Hz, unless otherwise specified. 50Hz timings are 1.2 times 60Hz timings.

PARAMETER

SYMBOL

MIN

TYPE

MAX

UNIT

SYNC Frequency

fs

40

-

70

Hz

SENS/EXT Duration

50

-

Infinite

ms

TRIG Pulse Width

-

33

-

µs

7237-041395-3

OUTPUT

DRIVER

DIGITAL

COMPARATOR

Ø

MEMORY

PHASE

LOCK

LOOP

CONTROL

LOGIC

BUF

BUF

BUF

BUF

SYNC

CAP

MODE

EXT

SENS

FIGURE 4

LS7237 BLOCK DIAGRAM

4

3

2

6

5

1

7

(+V)

(-V)

8

TRIG

Ø

POINTER