6525-030713-1

FEATURES:

•

Power derived from 3.0V Lithium battery

•

•

25

μA maximum quiescent current (LS6525)

•

30

μA maximum quiescent current (LS6526)

•

Direct interface with PIR sensor

•

Analog signal and digital interrupt signal outputs for interfacing

with a MCU

•

2.175V regulated output

•

Low battery indicator output (LS6526)

•

LS6525 (DIP), LS6525-S (SOIC)

LS6526 (DIP), LS6526-S (SOIC)

APPLICATIONS:

The low operating voltage and low current drain make the LS6525 /

LS6526 ideal for microcontroller based portable applications such as

battery operated motion detectors and photographic equipment,

automatic doors, intrusion detection, and anywhere electric outlets

are not available.

DESCRIPTION:

The LS6525 / LS6526 is a CMOS integrated circuit designed for

detecting motion from a PIR sensor and is microcontroller interface

ready. It uses a 3.0V Li battery as a source of energy for its

operation. The detailed description of the functional blocks is as

follows (refer to Figure 2).

AMPLIFIERS

The input PIR preamplifier, AMP1, has a nominal gain set at 29V/V

using internal resistors. An internal bias is used so that AMP1O

output has a quiescent voltage of 1.1V. The output of the PIR

amplifier is AC coupled to a second amplifier (AMP2) which uses

external components to set the gain. This second stage is internally

biased and applied to a window comparator which has lower and

higher trip levels set with respect to that bias. External components

are used to set a typical gain of 22V/V. Amplified signals greater in

magnitude than the trip levels will cause an interrupt signal to be

generated at the INT open drain output, pin 12. The INT output can

The output of the PIR amplifier is also AC coupled to an additional

amplifier (MCU amplifier) which uses external components to set the

gain. An internal bias set the MCO output at 0.5V and external

resistors set a typical gain = 10V/V, the MCO output signal can be

applied to a microcontroller input for processing.

Figure 1

INPUT / OUTPUT DESCRIPTION

PIN1 – PYRO Input – Non-inverting input of PIR amplifier AC

coupled to source of PIR signal.

PIN2 – VREG Output – This output provides power to the PIR

Sensor circuit and for all the internal amplifier circuitry.

PIN3 – AMP1O Output – Output terminal of the PIR amplifier

PIN4 – MCP – 0.5V internal bias. (Internal use only. No external

components.)

PIN5 – MCN Input – Inverting input to the MCU amplifier.

PIN6 – MCO Output – Output of the MCU amplifier.

BATTERY POWERED LOW-POWER PIR SENSOR INTERFACE

Mar 2013

LS6525

LS6526

PIN ASSIGNMENT