R1 = 20k

Ω, 1W

R2 = 470k

Ω, 1/4W

R3 = 1k

Ω, 1/4W

R4 = 350k

Ω, 1/4W,1%

R5 = 10M

Ω, 1/4W

R6 = 100

Ω, 1/4W

R7 = See Note 1

C1 = 47µF, 16V

C2 = 1000pF, 16V

C3 = 1000pF, 1kV

R1 = 39k

Ω, 2W

R2 = 910k

Ω, 1/4W

R4 = 420k

Ω, 1/4W, 1%

D1 = 1N4005

T1 = Q4004L4 (Typical Triac)

or Q4004F41 (Typical Triac)

All other values remain the same.

C4 = 1000pF, 1kV

C5 = 0.03µF, 16V (only for Figure 5)

C6 = 1µF, 16V

C7 = See Note 1

Z1 =

5.1V, 1/4W Zener

D1 = 1N4004

D2 = 1N4148

D3 = 1N4148

T1 =

Q2004L4 (Typical Triac)

or Q2004F41 (Typical Triac)

220VAC APPLICATION

115VAC APPLICATION

(1) Resistor should be placed adjacent to Pin 1.

(1)

(1

)

NOTE 1: See RAMP input description for determining values for R7 and C7.

NOTE 2: A good PCB layout using through-hole components will provide protection for ESD introduced at the Touch Plate in the range

of 25kV. Using surface mount components and/or a poor PCB layout can reduce the ESD protection. The OEM can increase

the ESD protection provided by the product with any combination of the following steps:

Step 1: The most effective and least costly way to increase ESD protection is to create a spark gap around the Touch Plate input on

the PCB. This will increase ESD protection on a good PCB layout to abut 35kV. The gap should be made with a split metal ring

with each side of the metal ring connected back to opposite sides of the AC line. This ensures that a path for the spark back to

house ground through AC Neutral exists independent of line plug polarity. The split ring and the center conduction plate should

be constructed so that the spacing between them conforms to UL requirements. The spark gap will absorb most of the ESD

leaving a remnant of about 10kV for the rest of the circuit to absorb.

Step 2: Increase R3 from 1k

(A minimal loss in touch sensitivity may be experienced.)

Step 3: Replace diodes D2 and D3 (1N4148) with Schottky diodes (1N5819 or similar)

7540-060906-4

AC

MAINS

LOAD

R1

R3

R4

D1

FIGURE 5. TOUCH LAMP APPLICATION SCHEMATIC

C3

C4

D2

8

7

6

5

CONT

D3

R2

TOUCH

PLATE

(LAMP BODY)

C2

T1

G

MT2

MT1

Z1

C5

R5

C1

+

-

+V

-V

LS7540

C6

+

-

C7

R6

1

2

3

4

TRIG/

R7

#1