FEATURES:

• Low Quiescent Current

• Direct Interface with PIR Sensor

• Two-Stage Differential Amplifier

• Amplifier Gain and Bandwidth externally controlled

• Window Comparator and Digital Filter limit Noise

• Triac or Relay Output Drive

• Programmable Output Duration Timer

• Ambient Light Level Inhibit input

• Selectable Dead Time

• Single or Dual Pulse Detection

• Timing derived from RC Oscillator or 50Hz/60Hz AC

• Regulated 5V Output for PIR Sensor

• Motion Detection LED Indicator

• Triac can drive Incandescent or Fluorescent Lamps

• LS6501LP (DIP), LS6501LP-S (SOIC-NB)

LS6501LP-SW (SOIC-WB) - See Figure 1

APPLICATIONS:

• Automatic Light Control

• Intrusion Alarm

DESCRIPTION: (See Figure 2)

The LS6501LP is a monolithic, CMOS Silicon Gate in-

tegrated circuit, designed for detecting motion from a PIR

Sensor and initiating appropriate responses. The detailed

description of the functional blocks is as follows:

DIFFERENTIAL AMPLIFIER

Each stage of the two stage Differential Amplifier can be set

to have its own amplification and bandwidth. The two inputs

to the first stage allow for single ended or differential con-

nection to PIR Sensors. This stage can be biased anywhere

in its dynamic range. The second stage is internally biased

so that the Window Comparator’s lower and higher thresh-

olds can be fixed relative to this bias.

WINDOW COMPARATOR

The Window Comparator provides noise filtering by enabling

only those signals equal to or greater than a fixed threshold

at the output of the Differential Amplifier to appear at the

output of the Window Comparator.

COMPARATOR DIGITAL FILTER

The output of the Window Comparator is filtered so that

motion must be present for a certain duration before it can

be recognized and appear as pulses at the Digital Filter

output.

OUTPUT DURATION TIMER

The voltage level at the TIMER CONTROL input can

select 16 different timeouts for this Timer (See Table 1).

The selection can be made by varying the setting of a

potentiometer. The Timer is retriggerable and controls

the ON duration of the TRIAC/RELAY output. The trigger

for the Timer is generated from pulses appearing at the

Digital Filter output.

SINGLE PULSE/DUAL PULSE MODES

A Single Pulse or Dual Pulse (two pulses occurring within

a specified time period) at the Digital Filter output can be

selected as the trigger for the Output Duration Timer.

This selection is made by the logic level at the PULSE

MODE SELECT input. Logic 0 = Single Pulse Mode,

logic 1 = Dual Pulse Mode.

LED OUTPUT

This is an open drain output which is turned on by pulses

generated by a retriggerable one-shot. The one-shot is

triggered by the leading edge of pulses appearing at the

Digital Filter output. When turned on, this output can sink

current from a series Resistor-LED network returned to a

the LED lighting whenever motion is detected.

PIR MOTION DETECTOR

July 2001

6501LP-071201-1

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

DIFF. AMP. 2 INPUT (-)

DIFF. AMP. 2 OUTPUT

AC INPUT

OSCILLATOR INPUT

TRIAC/RELAY OUTPUT

DIFF. AMP 1 INPUT (-)

DIFF. AMP 1 INPUT (+)

5V REGULATOR OUTPUT

TIMER CONTROL INPUT

DEAD TIME SELECT INPUT

INHIBIT INPUT

PULSE MODE

SELECT INPUT

LED OUTPUT

PIN ASSIGNMENT - TOP VIEW

FIGURE 1

DIFF. AMP. 1 OUTPUT

LSI/CSI

LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747

(631) 271-0400 FAX (631) 271-0405

LS6501LP

UL

®

A3800