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) PIN ASSIGNMENT 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). Figure 1 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. 6525-030713-1 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. PIN7 – V1P1 – Internally biased to 1.1V and applied to non-inverting input of AMP2. Requires an external bypass capacitor. PIN8 – AMP2N – Inverting input of AMP2 amplifier. PIN9 – AMP2O – Output of the AMP2 amplifier. PIN10 – NC – For LS6525. PIN10 – LOBAT Output – For LS6526 only. Open drain output requiring an external pull-up resistor to a power-supply that can be higher than VDD. An active low at the output signifies that a low battery condition exists. PIN11 – TEST – This pin is not used and must be tied to ground. PIN12 – INT Output – Open drain output requiring an external pull-up resistor to a power supply that can be higher than VDD. A recognized Interrupt signal will be an active low at this output. PIN13 – VDD – Power Supply Voltage PIN14 – VSS – Power Supply Ground 6525-030713-2 ABSOLUTE MAXIMUM RATINGS: PARAMETER DC Supply Voltage Input Voltage Operating Temperature Storage Temperature SYMBOL VDD VIN TA TSTG VALUE +7 VSS - 0.3 to VDD + 0.3 -40 to +70 -65 to +150 ELECTRICAL CHARACTERISTICS: (All voltages referenced to VSS, TA = 25°C, VDD = 2.3V - 3.6V, unless otherwise specified.) PARAMETER SYMBOL MIN TYP MAX SUPPLY CURRENT: VDD = 2.3V – 3.6V IDD 25 IDD 30 REGULATOR: Voltage VR 2.13 2.175 2.22 Source Current Capability IR 25 UNIT V V °C °C UNIT CONDITIONS μA μA LS6525, No Load@VREG LS6526, No Load@VREG V μA AMPLIFIERS: PIR Amplifier Gain GP Input Impedance MCU amplifier / AMP2 RP Open Loop Gain GM 70 MCO Output Quiescent Voltage AMP2 Internal Reference Window -Comparator amplifier Input Sensitivity to INT Output VQ VIR 0.48 VS 120 Comparator VLO, THRESHOLD VHI, THRESHOLD INT Output VOL, INT VPULL-UP Lobat Trip Voltage Hysteresis VTRIP Hys VOL, LOBAT VPULL-UP 6525-030713-3 28 29.5 32 V/V Vi/p 1mVP-P, 10Hz RL = No Load to 3MΩ MΩ 2 dB 0.5 1.1 0.52 V V μVP 1.02 1.18 AMP1 and AMP2 cascaded for net gain = 675V/V V V 0.1 5.5 V V 0.1 5.5 V V V V 2.45 0.1 RPULL-UP = 2MΩ, VPULL-UP = 3.6V RPULL-UP = 2MΩ, VPULL-UP = 3.6V Figure 2 Block Diagram 6525-030713-4 L1 68nH R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 2MΩ 10kΩ 4.7MΩ 442kΩ 1MΩ 10MΩ 100kΩ 2MΩ 10MΩ 100kΩ C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 1μF 1μF 1μF 47pF 47pF 3.3μF 1μF 3.3nF 0.16μF 10μF B1 Typical battery used: 3V CR123A Lithium PIR Excelitas LHI968 Pyro (Typical) Figure 3 Application schematic for LS6526. For the LS6525, pin 10 has no connection. The gain of AMP2 is set using R6 and R4 to a nominal gain of 22V/V. The MCU amplifier gain is set to 10V/V using R9 and R5. R10-C9 and R7-C8 are additional filter stages for the MCO and INT outputs when applied to the microcontroller. 6525-030713-5