LS6525 Datasheet, PDF (1/5 Pages) LSI Computer Systems – BATTERY POWERED LOW-POWER PIR SENSOR INTERFACE

LS6525
LS6526
Mar 2013
BATTERY POWERED LOW-POWER PIR SENSOR INTERFACE
FEATURES:
• Power derived from 3.0V Lithium battery
• VDD operating range 2.3V to 3.6V
• 25μA maximum quiescent current (LS6525)
• 30μA 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
be pulled to a voltage higher than VDD (pin 13).
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.
PIN ASSIGNMENT
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.
6525-030713-1