Touch Control Halogen Light Dimmer
(8 Pins)

LS7634-S, LS7634, LS7634FO-S, LS7634FO, LS7635-S, LS7635, LS7635FO-S, LS7635FO

Category: Lighting Controls

Status: In Production

Stock Availability: DIP, SOIC

All of our Standard Products are RoHS Compliant

For pricing and availability you may contact us, or request a quote. Most of our standard parts are available for purchase on Digi-Key, and through our Distributors.

Features:

• LS7634 functionally similar to LS7631
• LS7635 functionally similar to LS7632
• Compatible with virtually all electronic transformers.
• “FO” versions power up Full On.

Description:

A typical electronic dimmer may not operate properly with the inductive load encountered when driving a transformer-coupled low voltage halogen lamp. The inductive load can cause a phenomenon called half-waving, wherein the triac fires in alternate half-cycles only, which may lead to the thermal destruction of the load transformer. The problems encountered in driving an inductive load are addressed by the LS7634/LS7635 family of CMOS ICs as follows:

1. Delayed triac cut-off
When a trigger pulse is due to occur at a conduction angle which coincides with the on-state of the triac, the trigger pulse is delayed until the triac has turned off. This eliminates the underlying cause of half-waving.

2. Delayed triac turn-on and safety shutdown
With inductive loads, the holding current needed to maintain the triac on-state may seriously lag behind the gate trigger signal causing the triac to turn off prematurely. If the frequency of occurrences of the delayed turn-on exceeds a preset threshold, a shutdown is initiated by turning off the triac trigger pulses. The safety shutdown threshold value is accumulated in a 4-bit Up/Down counter. The count increments for every occurrence of delayed turn-on and decrements once every 8 SYNC pulses (AC line cycles). The counter will not decrement below zero. If the count reaches 15, the safety shutdown is effected.

Ordering Info

Code
Package
Notes

P/N

RoHS Compliant Standard plastic DIP

1, 2, 3

P/N – S

RoHS Compliant Standard SOIC

1, 2, 3, 4

P/N – SW

RoHS Compliant Widebody SOIC option

1, 2, 3, 4

P/N – S14

RoHS Compliant 14-pin SOIC version of 8-pin part

1, 2, 3, 4

P/N – TS

RoHS Compliant TSSOP

1, 2, 3, 4

P/N – TS24

RoHS Compliant 24-pin TSSOP version of 20-pin part

1, 2, 3, 4

Example: LSxxxx-TS = the LSxxxx in the RoHS Compliant TSSOP package-type

Note 1: See Table for package body widths

Note 2: Package outline drawings conform to JEDEC standards

Note 3: Packages shipped in anti-static tubes

Note 4: Tape and Reel option available. Contact factory for details

ADDITIONAL ORDERING OPTIONS:

Probed Wafers (P/N-PW), Waffle Packed Die (P/N-WP)

Package Body Widths
# of Pins
P/N, -C, -CM
-S
-SW
-TS

8

300

150

14

300

150

173

16

300

150

300

18

300

300

20

300

300

173

24

600

300

173

28

600

300

173

38

173

40

600

44

240

LSI/CSI