SENSOR is a PNP comparator input which accepts either a sine

wave or a square wave input. This input is protected from excur-

rent is limited to 1.5mA. It has an active clamp set to zero volts to

prevent negative input voltages from disrupting normal opera-

current is limited to 1.5mA max. using a series resistor of 100k½.

Simultaneously energizing the source and sink on either leg is

not permitted, i.e. Q1 & Q2 or Q3 & Q4 cannot be energized

simultaneously.

Circuit function is not affected by inductive transients due to coil

loads as specified in the Transition States section.

The transition states occur as indicated in Table 1 without any

intermediate states permitted.

Table 1: Transition States

The polarity definition for the coil driver outputs is as follows:

Connect

Connect

Polarity

Coil +

Coil -

Positive (+)

Gnd

Negative (-)

Gnd

The speed sensor input frequency is either divided by one or divid-

ed by two depending on the state of the SELECT input as follows:

Logic 0 = divide by 2

Logic 1 = divide by 1

Divider Select Input

Output State Table

State

Coil A

Coil B

0+

+

1

OFF

+

2-

+

3

-

OFF

4-

-

5

OFF

-

6+

-

7

+

OFF

Coil Driver Outputs

Speed Sensor Input

3

Circuit Operation

Short

Circuit

Sense

Resistor

Coil

Short

Circuit

Sense

Resistor

Gnd

Q3

Q4

Q1

Q2

Overvoltage

and

Short

Circuit

Protection

Figure 1: Coil Driver Output

Figure 3: Divide by 2 SELECT Mode

DIVIDE BY TWO MODE SELECT = Gnd

COILA+

COILAÐ

COILB+

COILBÐ

SELECT

Gnd

SENSOR

CS4161

IGN

D1

R1

R3

Z1

C1

C2

R2

C3

Buffered Speed Signal

(Open Collector Drive)

COIL A

COIL B

Odometer Application Diagram

C1 - 10µF

C2 - 0.1µF

C3 - 0.01µF

R1 - 3.9½, 500mW

R2 - 100k½

R3 - 15k½

D1 - 1A, 600PIV

Z1 - 50V, 500mW

COIL A - 210 ±12½, 80mH

COIL B - 210 ±12½, 80mH

Figure 2: Divide by 1 SELECT Mode